Provided by: ffmpeg_7.1-3ubuntu1_amd64 
NAME
ffprobe - ffprobe media prober
SYNOPSIS
ffprobe [options] input_url
DESCRIPTION
ffprobe gathers information from multimedia streams and prints it in human- and machine-
readable fashion.
For example it can be used to check the format of the container used by a multimedia
stream and the format and type of each media stream contained in it.
If a url is specified in input, ffprobe will try to open and probe the url content. If the
url cannot be opened or recognized as a multimedia file, a positive exit code is returned.
If no output is specified as output with o ffprobe will write to stdout.
ffprobe may be employed both as a standalone application or in combination with a textual
filter, which may perform more sophisticated processing, e.g. statistical processing or
plotting.
Options are used to list some of the formats supported by ffprobe or for specifying which
information to display, and for setting how ffprobe will show it.
ffprobe output is designed to be easily parsable by a textual filter, and consists of one
or more sections of a form defined by the selected writer, which is specified by the
output_format option.
Sections may contain other nested sections, and are identified by a name (which may be
shared by other sections), and an unique name. See the output of sections.
Metadata tags stored in the container or in the streams are recognized and printed in the
corresponding "FORMAT", "STREAM", "STREAM_GROUP_STREAM" or "PROGRAM_STREAM" section.
OPTIONS
All the numerical options, if not specified otherwise, accept a string representing a
number as input, which may be followed by one of the SI unit prefixes, for example: 'K',
'M', or 'G'.
If 'i' is appended to the SI unit prefix, the complete prefix will be interpreted as a
unit prefix for binary multiples, which are based on powers of 1024 instead of powers of
1000. Appending 'B' to the SI unit prefix multiplies the value by 8. This allows using,
for example: 'KB', 'MiB', 'G' and 'B' as number suffixes.
Options which do not take arguments are boolean options, and set the corresponding value
to true. They can be set to false by prefixing the option name with "no". For example
using "-nofoo" will set the boolean option with name "foo" to false.
Options that take arguments support a special syntax where the argument given on the
command line is interpreted as a path to the file from which the actual argument value is
loaded. To use this feature, add a forward slash '/' immediately before the option name
(after the leading dash). E.g.
ffmpeg -i INPUT -/filter:v filter.script OUTPUT
will load a filtergraph description from the file named filter.script.
Stream specifiers
Some options are applied per-stream, e.g. bitrate or codec. Stream specifiers are used to
precisely specify which stream(s) a given option belongs to.
A stream specifier is a string generally appended to the option name and separated from it
by a colon. E.g. "-codec:a:1 ac3" contains the "a:1" stream specifier, which matches the
second audio stream. Therefore, it would select the ac3 codec for the second audio stream.
A stream specifier can match several streams, so that the option is applied to all of
them. E.g. the stream specifier in "-b:a 128k" matches all audio streams.
An empty stream specifier matches all streams. For example, "-codec copy" or "-codec:
copy" would copy all the streams without reencoding.
Possible forms of stream specifiers are:
stream_index
Matches the stream with this index. E.g. "-threads:1 4" would set the thread count for
the second stream to 4. If stream_index is used as an additional stream specifier (see
below), then it selects stream number stream_index from the matching streams. Stream
numbering is based on the order of the streams as detected by libavformat except when
a stream group specifier or program ID is also specified. In this case it is based on
the ordering of the streams in the group or program.
stream_type[:additional_stream_specifier]
stream_type is one of following: 'v' or 'V' for video, 'a' for audio, 's' for
subtitle, 'd' for data, and 't' for attachments. 'v' matches all video streams, 'V'
only matches video streams which are not attached pictures, video thumbnails or cover
arts. If additional_stream_specifier is used, then it matches streams which both have
this type and match the additional_stream_specifier. Otherwise, it matches all streams
of the specified type.
g:group_specifier[:additional_stream_specifier]
Matches streams which are in the group with the specifier group_specifier. if
additional_stream_specifier is used, then it matches streams which both are part of
the group and match the additional_stream_specifier. group_specifier may be one of
the following:
group_index
Match the stream with this group index.
#group_id or i:group_id
Match the stream with this group id.
p:program_id[:additional_stream_specifier]
Matches streams which are in the program with the id program_id. If
additional_stream_specifier is used, then it matches streams which both are part of
the program and match the additional_stream_specifier.
#stream_id or i:stream_id
Match the stream by stream id (e.g. PID in MPEG-TS container).
m:key[:value]
Matches streams with the metadata tag key having the specified value. If value is not
given, matches streams that contain the given tag with any value.
disp:dispositions[:additional_stream_specifier]
Matches streams with the given disposition(s). dispositions is a list of one or more
dispositions (as printed by the -dispositions option) joined with '+'.
u Matches streams with usable configuration, the codec must be defined and the essential
information such as video dimension or audio sample rate must be present.
Note that in ffmpeg, matching by metadata will only work properly for input files.
Generic options
These options are shared amongst the ff* tools.
-L Show license.
-h, -?, -help, --help [arg]
Show help. An optional parameter may be specified to print help about a specific item.
If no argument is specified, only basic (non advanced) tool options are shown.
Possible values of arg are:
long
Print advanced tool options in addition to the basic tool options.
full
Print complete list of options, including shared and private options for encoders,
decoders, demuxers, muxers, filters, etc.
decoder=decoder_name
Print detailed information about the decoder named decoder_name. Use the -decoders
option to get a list of all decoders.
encoder=encoder_name
Print detailed information about the encoder named encoder_name. Use the -encoders
option to get a list of all encoders.
demuxer=demuxer_name
Print detailed information about the demuxer named demuxer_name. Use the -formats
option to get a list of all demuxers and muxers.
muxer=muxer_name
Print detailed information about the muxer named muxer_name. Use the -formats
option to get a list of all muxers and demuxers.
filter=filter_name
Print detailed information about the filter named filter_name. Use the -filters
option to get a list of all filters.
bsf=bitstream_filter_name
Print detailed information about the bitstream filter named bitstream_filter_name.
Use the -bsfs option to get a list of all bitstream filters.
protocol=protocol_name
Print detailed information about the protocol named protocol_name. Use the
-protocols option to get a list of all protocols.
-version
Show version.
-buildconf
Show the build configuration, one option per line.
-formats
Show available formats (including devices).
-demuxers
Show available demuxers.
-muxers
Show available muxers.
-devices
Show available devices.
-codecs
Show all codecs known to libavcodec.
Note that the term 'codec' is used throughout this documentation as a shortcut for
what is more correctly called a media bitstream format.
-decoders
Show available decoders.
-encoders
Show all available encoders.
-bsfs
Show available bitstream filters.
-protocols
Show available protocols.
-filters
Show available libavfilter filters.
-pix_fmts
Show available pixel formats.
-sample_fmts
Show available sample formats.
-layouts
Show channel names and standard channel layouts.
-dispositions
Show stream dispositions.
-colors
Show recognized color names.
-sources device[,opt1=val1[,opt2=val2]...]
Show autodetected sources of the input device. Some devices may provide system-
dependent source names that cannot be autodetected. The returned list cannot be
assumed to be always complete.
ffmpeg -sources pulse,server=192.168.0.4
-sinks device[,opt1=val1[,opt2=val2]...]
Show autodetected sinks of the output device. Some devices may provide system-
dependent sink names that cannot be autodetected. The returned list cannot be assumed
to be always complete.
ffmpeg -sinks pulse,server=192.168.0.4
-loglevel [flags+]loglevel | -v [flags+]loglevel
Set logging level and flags used by the library.
The optional flags prefix can consist of the following values:
repeat
Indicates that repeated log output should not be compressed to the first line and
the "Last message repeated n times" line will be omitted.
level
Indicates that log output should add a "[level]" prefix to each message line. This
can be used as an alternative to log coloring, e.g. when dumping the log to file.
Flags can also be used alone by adding a '+'/'-' prefix to set/reset a single flag
without affecting other flags or changing loglevel. When setting both flags and
loglevel, a '+' separator is expected between the last flags value and before
loglevel.
loglevel is a string or a number containing one of the following values:
quiet, -8
Show nothing at all; be silent.
panic, 0
Only show fatal errors which could lead the process to crash, such as an assertion
failure. This is not currently used for anything.
fatal, 8
Only show fatal errors. These are errors after which the process absolutely cannot
continue.
error, 16
Show all errors, including ones which can be recovered from.
warning, 24
Show all warnings and errors. Any message related to possibly incorrect or
unexpected events will be shown.
info, 32
Show informative messages during processing. This is in addition to warnings and
errors. This is the default value.
verbose, 40
Same as "info", except more verbose.
debug, 48
Show everything, including debugging information.
trace, 56
For example to enable repeated log output, add the "level" prefix, and set loglevel to
"verbose":
ffmpeg -loglevel repeat+level+verbose -i input output
Another example that enables repeated log output without affecting current state of
"level" prefix flag or loglevel:
ffmpeg [...] -loglevel +repeat
By default the program logs to stderr. If coloring is supported by the terminal,
colors are used to mark errors and warnings. Log coloring can be disabled setting the
environment variable AV_LOG_FORCE_NOCOLOR, or can be forced setting the environment
variable AV_LOG_FORCE_COLOR.
-report
Dump full command line and log output to a file named "program-YYYYMMDD-HHMMSS.log" in
the current directory. This file can be useful for bug reports. It also implies
"-loglevel debug".
Setting the environment variable FFREPORT to any value has the same effect. If the
value is a ':'-separated key=value sequence, these options will affect the report;
option values must be escaped if they contain special characters or the options
delimiter ':' (see the ``Quoting and escaping'' section in the ffmpeg-utils manual).
The following options are recognized:
file
set the file name to use for the report; %p is expanded to the name of the
program, %t is expanded to a timestamp, "%%" is expanded to a plain "%"
level
set the log verbosity level using a numerical value (see "-loglevel").
For example, to output a report to a file named ffreport.log using a log level of 32
(alias for log level "info"):
FFREPORT=file=ffreport.log:level=32 ffmpeg -i input output
Errors in parsing the environment variable are not fatal, and will not appear in the
report.
-hide_banner
Suppress printing banner.
All FFmpeg tools will normally show a copyright notice, build options and library
versions. This option can be used to suppress printing this information.
-cpuflags flags (global)
Allows setting and clearing cpu flags. This option is intended for testing. Do not use
it unless you know what you're doing.
ffmpeg -cpuflags -sse+mmx ...
ffmpeg -cpuflags mmx ...
ffmpeg -cpuflags 0 ...
Possible flags for this option are:
x86
mmx
mmxext
sse
sse2
sse2slow
sse3
sse3slow
ssse3
atom
sse4.1
sse4.2
avx
avx2
xop
fma3
fma4
3dnow
3dnowext
bmi1
bmi2
cmov
ARM
armv5te
armv6
armv6t2
vfp
vfpv3
neon
setend
AArch64
armv8
vfp
neon
PowerPC
altivec
Specific Processors
pentium2
pentium3
pentium4
k6
k62
athlon
athlonxp
k8
-cpucount count (global)
Override detection of CPU count. This option is intended for testing. Do not use it
unless you know what you're doing.
ffmpeg -cpucount 2
-max_alloc bytes
Set the maximum size limit for allocating a block on the heap by ffmpeg's family of
malloc functions. Exercise extreme caution when using this option. Don't use if you do
not understand the full consequence of doing so. Default is INT_MAX.
AVOptions
These options are provided directly by the libavformat, libavdevice and libavcodec
libraries. To see the list of available AVOptions, use the -help option. They are
separated into two categories:
generic
These options can be set for any container, codec or device. Generic options are
listed under AVFormatContext options for containers/devices and under AVCodecContext
options for codecs.
private
These options are specific to the given container, device or codec. Private options
are listed under their corresponding containers/devices/codecs.
For example to write an ID3v2.3 header instead of a default ID3v2.4 to an MP3 file, use
the id3v2_version private option of the MP3 muxer:
ffmpeg -i input.flac -id3v2_version 3 out.mp3
All codec AVOptions are per-stream, and thus a stream specifier should be attached to
them:
ffmpeg -i multichannel.mxf -map 0:v:0 -map 0:a:0 -map 0:a:0 -c:a:0 ac3 -b:a:0 640k -ac:a:1 2 -c:a:1 aac -b:2 128k out.mp4
In the above example, a multichannel audio stream is mapped twice for output. The first
instance is encoded with codec ac3 and bitrate 640k. The second instance is downmixed to
2 channels and encoded with codec aac. A bitrate of 128k is specified for it using
absolute index of the output stream.
Note: the -nooption syntax cannot be used for boolean AVOptions, use -option 0/-option 1.
Note: the old undocumented way of specifying per-stream AVOptions by prepending v/a/s to
the options name is now obsolete and will be removed soon.
Main options
-f format
Force format to use.
-unit
Show the unit of the displayed values.
-prefix
Use SI prefixes for the displayed values. Unless the "-byte_binary_prefix" option is
used all the prefixes are decimal.
-byte_binary_prefix
Force the use of binary prefixes for byte values.
-sexagesimal
Use sexagesimal format HH:MM:SS.MICROSECONDS for time values.
-pretty
Prettify the format of the displayed values, it corresponds to the options "-unit
-prefix -byte_binary_prefix -sexagesimal".
-output_format, -of, -print_format writer_name[=writer_options]
Set the output printing format.
writer_name specifies the name of the writer, and writer_options specifies the options
to be passed to the writer.
For example for printing the output in JSON format, specify:
-output_format json
For more details on the available output printing formats, see the Writers section
below.
-sections
Print sections structure and section information, and exit. The output is not meant to
be parsed by a machine.
-select_streams stream_specifier
Select only the streams specified by stream_specifier. This option affects only the
options related to streams (e.g. "show_streams", "show_packets", etc.).
For example to show only audio streams, you can use the command:
ffprobe -show_streams -select_streams a INPUT
To show only video packets belonging to the video stream with index 1:
ffprobe -show_packets -select_streams v:1 INPUT
-show_data
Show payload data, as a hexadecimal and ASCII dump. Coupled with -show_packets, it
will dump the packets' data. Coupled with -show_streams, it will dump the codec
extradata.
The dump is printed as the "data" field. It may contain newlines.
-show_data_hash algorithm
Show a hash of payload data, for packets with -show_packets and for codec extradata
with -show_streams.
-show_error
Show information about the error found when trying to probe the input.
The error information is printed within a section with name "ERROR".
-show_format
Show information about the container format of the input multimedia stream.
All the container format information is printed within a section with name "FORMAT".
-show_format_entry name
Like -show_format, but only prints the specified entry of the container format
information, rather than all. This option may be given more than once, then all
specified entries will be shown.
This option is deprecated, use "show_entries" instead.
-show_entries section_entries
Set list of entries to show.
Entries are specified according to the following syntax. section_entries contains a
list of section entries separated by ":". Each section entry is composed by a section
name (or unique name), optionally followed by a list of entries local to that section,
separated by ",".
If section name is specified but is followed by no "=", all entries are printed to
output, together with all the contained sections. Otherwise only the entries specified
in the local section entries list are printed. In particular, if "=" is specified but
the list of local entries is empty, then no entries will be shown for that section.
Note that the order of specification of the local section entries is not honored in
the output, and the usual display order will be retained.
The formal syntax is given by:
<LOCAL_SECTION_ENTRIES> ::= <SECTION_ENTRY_NAME>[,<LOCAL_SECTION_ENTRIES>]
<SECTION_ENTRY> ::= <SECTION_NAME>[=[<LOCAL_SECTION_ENTRIES>]]
<SECTION_ENTRIES> ::= <SECTION_ENTRY>[:<SECTION_ENTRIES>]
For example, to show only the index and type of each stream, and the PTS time,
duration time, and stream index of the packets, you can specify the argument:
packet=pts_time,duration_time,stream_index : stream=index,codec_type
To show all the entries in the section "format", but only the codec type in the
section "stream", specify the argument:
format : stream=codec_type
To show all the tags in the stream and format sections:
stream_tags : format_tags
To show only the "title" tag (if available) in the stream sections:
stream_tags=title
-show_packets
Show information about each packet contained in the input multimedia stream.
The information for each single packet is printed within a dedicated section with name
"PACKET".
-show_frames
Show information about each frame and subtitle contained in the input multimedia
stream.
The information for each single frame is printed within a dedicated section with name
"FRAME" or "SUBTITLE".
-show_log loglevel
Show logging information from the decoder about each frame according to the value set
in loglevel, (see "-loglevel"). This option requires "-show_frames".
The information for each log message is printed within a dedicated section with name
"LOG".
-show_streams
Show information about each media stream contained in the input multimedia stream.
Each media stream information is printed within a dedicated section with name
"STREAM".
-show_programs
Show information about programs and their streams contained in the input multimedia
stream.
Each media stream information is printed within a dedicated section with name
"PROGRAM_STREAM".
-show_stream_groups
Show information about stream groups and their streams contained in the input
multimedia stream.
Each media stream information is printed within a dedicated section with name
"STREAM_GROUP_STREAM".
-show_chapters
Show information about chapters stored in the format.
Each chapter is printed within a dedicated section with name "CHAPTER".
-count_frames
Count the number of frames per stream and report it in the corresponding stream
section.
-count_packets
Count the number of packets per stream and report it in the corresponding stream
section.
-read_intervals read_intervals
Read only the specified intervals. read_intervals must be a sequence of interval
specifications separated by ",". ffprobe will seek to the interval starting point,
and will continue reading from that.
Each interval is specified by two optional parts, separated by "%".
The first part specifies the interval start position. It is interpreted as an absolute
position, or as a relative offset from the current position if it is preceded by the
"+" character. If this first part is not specified, no seeking will be performed when
reading this interval.
The second part specifies the interval end position. It is interpreted as an absolute
position, or as a relative offset from the current position if it is preceded by the
"+" character. If the offset specification starts with "#", it is interpreted as the
number of packets to read (not including the flushing packets) from the interval
start. If no second part is specified, the program will read until the end of the
input.
Note that seeking is not accurate, thus the actual interval start point may be
different from the specified position. Also, when an interval duration is specified,
the absolute end time will be computed by adding the duration to the interval start
point found by seeking the file, rather than to the specified start value.
The formal syntax is given by:
<INTERVAL> ::= [<START>|+<START_OFFSET>][%[<END>|+<END_OFFSET>]]
<INTERVALS> ::= <INTERVAL>[,<INTERVALS>]
A few examples follow.
• Seek to time 10, read packets until 20 seconds after the found seek point, then
seek to position "01:30" (1 minute and thirty seconds) and read packets until
position "01:45".
10%+20,01:30%01:45
• Read only 42 packets after seeking to position "01:23":
01:23%+#42
• Read only the first 20 seconds from the start:
%+20
• Read from the start until position "02:30":
%02:30
-show_private_data, -private
Show private data, that is data depending on the format of the particular shown
element. This option is enabled by default, but you may need to disable it for
specific uses, for example when creating XSD-compliant XML output.
-show_program_version
Show information related to program version.
Version information is printed within a section with name "PROGRAM_VERSION".
-show_library_versions
Show information related to library versions.
Version information for each library is printed within a section with name
"LIBRARY_VERSION".
-show_versions
Show information related to program and library versions. This is the equivalent of
setting both -show_program_version and -show_library_versions options.
-show_pixel_formats
Show information about all pixel formats supported by FFmpeg.
Pixel format information for each format is printed within a section with name
"PIXEL_FORMAT".
-show_optional_fields value
Some writers viz. JSON and XML, omit the printing of fields with invalid or non-
applicable values, while other writers always print them. This option enables one to
control this behaviour. Valid values are "always"/1, "never"/0 and "auto"/-1.
Default is auto.
-bitexact
Force bitexact output, useful to produce output which is not dependent on the specific
build.
-i input_url
Read input_url.
-o output_url
Write output to output_url. If not specified, the output is sent to stdout.
WRITERS
A writer defines the output format adopted by ffprobe, and will be used for printing all
the parts of the output.
A writer may accept one or more arguments, which specify the options to adopt. The options
are specified as a list of key=value pairs, separated by ":".
All writers support the following options:
string_validation, sv
Set string validation mode.
The following values are accepted.
fail
The writer will fail immediately in case an invalid string (UTF-8) sequence or
code point is found in the input. This is especially useful to validate input
metadata.
ignore
Any validation error will be ignored. This will result in possibly broken output,
especially with the json or xml writer.
replace
The writer will substitute invalid UTF-8 sequences or code points with the string
specified with the string_validation_replacement.
Default value is replace.
string_validation_replacement, svr
Set replacement string to use in case string_validation is set to replace.
In case the option is not specified, the writer will assume the empty string, that is
it will remove the invalid sequences from the input strings.
A description of the currently available writers follows.
default
Default format.
Print each section in the form:
[SECTION]
key1=val1
...
keyN=valN
[/SECTION]
Metadata tags are printed as a line in the corresponding FORMAT, STREAM,
STREAM_GROUP_STREAM or PROGRAM_STREAM section, and are prefixed by the string "TAG:".
A description of the accepted options follows.
nokey, nk
If set to 1 specify not to print the key of each field. Default value is 0.
noprint_wrappers, nw
If set to 1 specify not to print the section header and footer. Default value is 0.
compact, csv
Compact and CSV format.
The "csv" writer is equivalent to "compact", but supports different defaults.
Each section is printed on a single line. If no option is specified, the output has the
form:
section|key1=val1| ... |keyN=valN
Metadata tags are printed in the corresponding "format" or "stream" section. A metadata
tag key, if printed, is prefixed by the string "tag:".
The description of the accepted options follows.
item_sep, s
Specify the character to use for separating fields in the output line. It must be a
single printable character, it is "|" by default ("," for the "csv" writer).
nokey, nk
If set to 1 specify not to print the key of each field. Its default value is 0 (1 for
the "csv" writer).
escape, e
Set the escape mode to use, default to "c" ("csv" for the "csv" writer).
It can assume one of the following values:
c Perform C-like escaping. Strings containing a newline (\n), carriage return (\r),
a tab (\t), a form feed (\f), the escaping character (\) or the item separator
character SEP are escaped using C-like fashioned escaping, so that a newline is
converted to the sequence \n, a carriage return to \r, \ to \\ and the separator
SEP is converted to \SEP.
csv Perform CSV-like escaping, as described in RFC4180. Strings containing a newline
(\n), a carriage return (\r), a double quote ("), or SEP are enclosed in double-
quotes.
none
Perform no escaping.
print_section, p
Print the section name at the beginning of each line if the value is 1, disable it
with value set to 0. Default value is 1.
flat
Flat format.
A free-form output where each line contains an explicit key=value, such as
"streams.stream.3.tags.foo=bar". The output is shell escaped, so it can be directly
embedded in sh scripts as long as the separator character is an alphanumeric character or
an underscore (see sep_char option).
The description of the accepted options follows.
sep_char, s
Separator character used to separate the chapter, the section name, IDs and potential
tags in the printed field key.
Default value is ..
hierarchical, h
Specify if the section name specification should be hierarchical. If set to 1, and if
there is more than one section in the current chapter, the section name will be
prefixed by the name of the chapter. A value of 0 will disable this behavior.
Default value is 1.
ini
INI format output.
Print output in an INI based format.
The following conventions are adopted:
• all key and values are UTF-8
• . is the subgroup separator
• newline, \t, \f, \b and the following characters are escaped
• \ is the escape character
• # is the comment indicator
• = is the key/value separator
• : is not used but usually parsed as key/value separator
This writer accepts options as a list of key=value pairs, separated by :.
The description of the accepted options follows.
hierarchical, h
Specify if the section name specification should be hierarchical. If set to 1, and if
there is more than one section in the current chapter, the section name will be
prefixed by the name of the chapter. A value of 0 will disable this behavior.
Default value is 1.
json
JSON based format.
Each section is printed using JSON notation.
The description of the accepted options follows.
compact, c
If set to 1 enable compact output, that is each section will be printed on a single
line. Default value is 0.
For more information about JSON, see <http://www.json.org/>.
xml
XML based format.
The XML output is described in the XML schema description file ffprobe.xsd installed in
the FFmpeg datadir.
An updated version of the schema can be retrieved at the url
<http://www.ffmpeg.org/schema/ffprobe.xsd>, which redirects to the latest schema committed
into the FFmpeg development source code tree.
Note that the output issued will be compliant to the ffprobe.xsd schema only when no
special global output options (unit, prefix, byte_binary_prefix, sexagesimal etc.) are
specified.
The description of the accepted options follows.
fully_qualified, q
If set to 1 specify if the output should be fully qualified. Default value is 0. This
is required for generating an XML file which can be validated through an XSD file.
xsd_strict, x
If set to 1 perform more checks for ensuring that the output is XSD compliant. Default
value is 0. This option automatically sets fully_qualified to 1.
For more information about the XML format, see <https://www.w3.org/XML/>.
TIMECODE
ffprobe supports Timecode extraction:
• MPEG1/2 timecode is extracted from the GOP, and is available in the video stream
details (-show_streams, see timecode).
• MOV timecode is extracted from tmcd track, so is available in the tmcd stream metadata
(-show_streams, see TAG:timecode).
• DV, GXF and AVI timecodes are available in format metadata (-show_format, see
TAG:timecode).
SYNTAX
This section documents the syntax and formats employed by the FFmpeg libraries and tools.
Quoting and escaping
FFmpeg adopts the following quoting and escaping mechanism, unless explicitly specified.
The following rules are applied:
• ' and \ are special characters (respectively used for quoting and escaping). In
addition to them, there might be other special characters depending on the specific
syntax where the escaping and quoting are employed.
• A special character is escaped by prefixing it with a \.
• All characters enclosed between '' are included literally in the parsed string. The
quote character ' itself cannot be quoted, so you may need to close the quote and
escape it.
• Leading and trailing whitespaces, unless escaped or quoted, are removed from the
parsed string.
Note that you may need to add a second level of escaping when using the command line or a
script, which depends on the syntax of the adopted shell language.
The function "av_get_token" defined in libavutil/avstring.h can be used to parse a token
quoted or escaped according to the rules defined above.
The tool tools/ffescape in the FFmpeg source tree can be used to automatically quote or
escape a string in a script.
Examples
• Escape the string "Crime d'Amour" containing the "'" special character:
Crime d\'Amour
• The string above contains a quote, so the "'" needs to be escaped when quoting it:
'Crime d'\''Amour'
• Include leading or trailing whitespaces using quoting:
' this string starts and ends with whitespaces '
• Escaping and quoting can be mixed together:
' The string '\'string\'' is a string '
• To include a literal \ you can use either escaping or quoting:
'c:\foo' can be written as c:\\foo
Date
The accepted syntax is:
[(YYYY-MM-DD|YYYYMMDD)[T|t| ]]((HH:MM:SS[.m...]]])|(HHMMSS[.m...]]]))[Z]
now
If the value is "now" it takes the current time.
Time is local time unless Z is appended, in which case it is interpreted as UTC. If the
year-month-day part is not specified it takes the current year-month-day.
Time duration
There are two accepted syntaxes for expressing time duration.
[-][<HH>:]<MM>:<SS>[.<m>...]
HH expresses the number of hours, MM the number of minutes for a maximum of 2 digits, and
SS the number of seconds for a maximum of 2 digits. The m at the end expresses decimal
value for SS.
or
[-]<S>+[.<m>...][s|ms|us]
S expresses the number of seconds, with the optional decimal part m. The optional literal
suffixes s, ms or us indicate to interpret the value as seconds, milliseconds or
microseconds, respectively.
In both expressions, the optional - indicates negative duration.
Examples
The following examples are all valid time duration:
55 55 seconds
0.2 0.2 seconds
200ms
200 milliseconds, that's 0.2s
200000us
200000 microseconds, that's 0.2s
12:03:45
12 hours, 03 minutes and 45 seconds
23.189
23.189 seconds
Video size
Specify the size of the sourced video, it may be a string of the form widthxheight, or the
name of a size abbreviation.
The following abbreviations are recognized:
ntsc
720x480
pal 720x576
qntsc
352x240
qpal
352x288
sntsc
640x480
spal
768x576
film
352x240
ntsc-film
352x240
sqcif
128x96
qcif
176x144
cif 352x288
4cif
704x576
16cif
1408x1152
qqvga
160x120
qvga
320x240
vga 640x480
svga
800x600
xga 1024x768
uxga
1600x1200
qxga
2048x1536
sxga
1280x1024
qsxga
2560x2048
hsxga
5120x4096
wvga
852x480
wxga
1366x768
wsxga
1600x1024
wuxga
1920x1200
woxga
2560x1600
wqsxga
3200x2048
wquxga
3840x2400
whsxga
6400x4096
whuxga
7680x4800
cga 320x200
ega 640x350
hd480
852x480
hd720
1280x720
hd1080
1920x1080
2k 2048x1080
2kflat
1998x1080
2kscope
2048x858
4k 4096x2160
4kflat
3996x2160
4kscope
4096x1716
nhd 640x360
hqvga
240x160
wqvga
400x240
fwqvga
432x240
hvga
480x320
qhd 960x540
2kdci
2048x1080
4kdci
4096x2160
uhd2160
3840x2160
uhd4320
7680x4320
Video rate
Specify the frame rate of a video, expressed as the number of frames generated per second.
It has to be a string in the format frame_rate_num/frame_rate_den, an integer number, a
float number or a valid video frame rate abbreviation.
The following abbreviations are recognized:
ntsc
30000/1001
pal 25/1
qntsc
30000/1001
qpal
25/1
sntsc
30000/1001
spal
25/1
film
24/1
ntsc-film
24000/1001
Ratio
A ratio can be expressed as an expression, or in the form numerator:denominator.
Note that a ratio with infinite (1/0) or negative value is considered valid, so you should
check on the returned value if you want to exclude those values.
The undefined value can be expressed using the "0:0" string.
Color
It can be the name of a color as defined below (case insensitive match) or a
"[0x|#]RRGGBB[AA]" sequence, possibly followed by @ and a string representing the alpha
component.
The alpha component may be a string composed by "0x" followed by an hexadecimal number or
a decimal number between 0.0 and 1.0, which represents the opacity value (0x00 or 0.0
means completely transparent, 0xff or 1.0 completely opaque). If the alpha component is
not specified then 0xff is assumed.
The string random will result in a random color.
The following names of colors are recognized:
AliceBlue
0xF0F8FF
AntiqueWhite
0xFAEBD7
Aqua
0x00FFFF
Aquamarine
0x7FFFD4
Azure
0xF0FFFF
Beige
0xF5F5DC
Bisque
0xFFE4C4
Black
0x000000
BlanchedAlmond
0xFFEBCD
Blue
0x0000FF
BlueViolet
0x8A2BE2
Brown
0xA52A2A
BurlyWood
0xDEB887
CadetBlue
0x5F9EA0
Chartreuse
0x7FFF00
Chocolate
0xD2691E
Coral
0xFF7F50
CornflowerBlue
0x6495ED
Cornsilk
0xFFF8DC
Crimson
0xDC143C
Cyan
0x00FFFF
DarkBlue
0x00008B
DarkCyan
0x008B8B
DarkGoldenRod
0xB8860B
DarkGray
0xA9A9A9
DarkGreen
0x006400
DarkKhaki
0xBDB76B
DarkMagenta
0x8B008B
DarkOliveGreen
0x556B2F
Darkorange
0xFF8C00
DarkOrchid
0x9932CC
DarkRed
0x8B0000
DarkSalmon
0xE9967A
DarkSeaGreen
0x8FBC8F
DarkSlateBlue
0x483D8B
DarkSlateGray
0x2F4F4F
DarkTurquoise
0x00CED1
DarkViolet
0x9400D3
DeepPink
0xFF1493
DeepSkyBlue
0x00BFFF
DimGray
0x696969
DodgerBlue
0x1E90FF
FireBrick
0xB22222
FloralWhite
0xFFFAF0
ForestGreen
0x228B22
Fuchsia
0xFF00FF
Gainsboro
0xDCDCDC
GhostWhite
0xF8F8FF
Gold
0xFFD700
GoldenRod
0xDAA520
Gray
0x808080
Green
0x008000
GreenYellow
0xADFF2F
HoneyDew
0xF0FFF0
HotPink
0xFF69B4
IndianRed
0xCD5C5C
Indigo
0x4B0082
Ivory
0xFFFFF0
Khaki
0xF0E68C
Lavender
0xE6E6FA
LavenderBlush
0xFFF0F5
LawnGreen
0x7CFC00
LemonChiffon
0xFFFACD
LightBlue
0xADD8E6
LightCoral
0xF08080
LightCyan
0xE0FFFF
LightGoldenRodYellow
0xFAFAD2
LightGreen
0x90EE90
LightGrey
0xD3D3D3
LightPink
0xFFB6C1
LightSalmon
0xFFA07A
LightSeaGreen
0x20B2AA
LightSkyBlue
0x87CEFA
LightSlateGray
0x778899
LightSteelBlue
0xB0C4DE
LightYellow
0xFFFFE0
Lime
0x00FF00
LimeGreen
0x32CD32
Linen
0xFAF0E6
Magenta
0xFF00FF
Maroon
0x800000
MediumAquaMarine
0x66CDAA
MediumBlue
0x0000CD
MediumOrchid
0xBA55D3
MediumPurple
0x9370D8
MediumSeaGreen
0x3CB371
MediumSlateBlue
0x7B68EE
MediumSpringGreen
0x00FA9A
MediumTurquoise
0x48D1CC
MediumVioletRed
0xC71585
MidnightBlue
0x191970
MintCream
0xF5FFFA
MistyRose
0xFFE4E1
Moccasin
0xFFE4B5
NavajoWhite
0xFFDEAD
Navy
0x000080
OldLace
0xFDF5E6
Olive
0x808000
OliveDrab
0x6B8E23
Orange
0xFFA500
OrangeRed
0xFF4500
Orchid
0xDA70D6
PaleGoldenRod
0xEEE8AA
PaleGreen
0x98FB98
PaleTurquoise
0xAFEEEE
PaleVioletRed
0xD87093
PapayaWhip
0xFFEFD5
PeachPuff
0xFFDAB9
Peru
0xCD853F
Pink
0xFFC0CB
Plum
0xDDA0DD
PowderBlue
0xB0E0E6
Purple
0x800080
Red 0xFF0000
RosyBrown
0xBC8F8F
RoyalBlue
0x4169E1
SaddleBrown
0x8B4513
Salmon
0xFA8072
SandyBrown
0xF4A460
SeaGreen
0x2E8B57
SeaShell
0xFFF5EE
Sienna
0xA0522D
Silver
0xC0C0C0
SkyBlue
0x87CEEB
SlateBlue
0x6A5ACD
SlateGray
0x708090
Snow
0xFFFAFA
SpringGreen
0x00FF7F
SteelBlue
0x4682B4
Tan 0xD2B48C
Teal
0x008080
Thistle
0xD8BFD8
Tomato
0xFF6347
Turquoise
0x40E0D0
Violet
0xEE82EE
Wheat
0xF5DEB3
White
0xFFFFFF
WhiteSmoke
0xF5F5F5
Yellow
0xFFFF00
YellowGreen
0x9ACD32
Channel Layout
A channel layout specifies the spatial disposition of the channels in a multi-channel
audio stream. To specify a channel layout, FFmpeg makes use of a special syntax.
Individual channels are identified by an id, as given by the table below:
FL front left
FR front right
FC front center
LFE low frequency
BL back left
BR back right
FLC front left-of-center
FRC front right-of-center
BC back center
SL side left
SR side right
TC top center
TFL top front left
TFC top front center
TFR top front right
TBL top back left
TBC top back center
TBR top back right
DL downmix left
DR downmix right
WL wide left
WR wide right
SDL surround direct left
SDR surround direct right
LFE2
low frequency 2
Standard channel layout compositions can be specified by using the following identifiers:
mono
FC
stereo
FL+FR
2.1 FL+FR+LFE
3.0 FL+FR+FC
3.0(back)
FL+FR+BC
4.0 FL+FR+FC+BC
quad
FL+FR+BL+BR
quad(side)
FL+FR+SL+SR
3.1 FL+FR+FC+LFE
5.0 FL+FR+FC+BL+BR
5.0(side)
FL+FR+FC+SL+SR
4.1 FL+FR+FC+LFE+BC
5.1 FL+FR+FC+LFE+BL+BR
5.1(side)
FL+FR+FC+LFE+SL+SR
6.0 FL+FR+FC+BC+SL+SR
6.0(front)
FL+FR+FLC+FRC+SL+SR
3.1.2
FL+FR+FC+LFE+TFL+TFR
hexagonal
FL+FR+FC+BL+BR+BC
6.1 FL+FR+FC+LFE+BC+SL+SR
6.1 FL+FR+FC+LFE+BL+BR+BC
6.1(front)
FL+FR+LFE+FLC+FRC+SL+SR
7.0 FL+FR+FC+BL+BR+SL+SR
7.0(front)
FL+FR+FC+FLC+FRC+SL+SR
7.1 FL+FR+FC+LFE+BL+BR+SL+SR
7.1(wide)
FL+FR+FC+LFE+BL+BR+FLC+FRC
7.1(wide-side)
FL+FR+FC+LFE+FLC+FRC+SL+SR
5.1.2
FL+FR+FC+LFE+BL+BR+TFL+TFR
octagonal
FL+FR+FC+BL+BR+BC+SL+SR
cube
FL+FR+BL+BR+TFL+TFR+TBL+TBR
5.1.4
FL+FR+FC+LFE+BL+BR+TFL+TFR+TBL+TBR
7.1.2
FL+FR+FC+LFE+BL+BR+SL+SR+TFL+TFR
7.1.4
FL+FR+FC+LFE+BL+BR+SL+SR+TFL+TFR+TBL+TBR
7.2.3
FL+FR+FC+LFE+BL+BR+SL+SR+TFL+TFR+TBC+LFE2
9.1.4
FL+FR+FC+LFE+BL+BR+FLC+FRC+SL+SR+TFL+TFR+TBL+TBR
hexadecagonal
FL+FR+FC+BL+BR+BC+SL+SR+WL+WR+TBL+TBR+TBC+TFC+TFL+TFR
downmix
DL+DR
22.2
FL+FR+FC+LFE+BL+BR+FLC+FRC+BC+SL+SR+TC+TFL+TFC+TFR+TBL+TBC+TBR+LFE2+TSL+TSR+BFC+BFL+BFR
A custom channel layout can be specified as a sequence of terms, separated by '+'. Each
term can be:
• the name of a single channel (e.g. FL, FR, FC, LFE, etc.), each optionally containing
a custom name after a '@', (e.g. FL@Left, FR@Right, FC@Center, LFE@Low_Frequency,
etc.)
A standard channel layout can be specified by the following:
• the name of a single channel (e.g. FL, FR, FC, LFE, etc.)
• the name of a standard channel layout (e.g. mono, stereo, 4.0, quad, 5.0, etc.)
• a number of channels, in decimal, followed by 'c', yielding the default channel layout
for that number of channels (see the function "av_channel_layout_default"). Note that
not all channel counts have a default layout.
• a number of channels, in decimal, followed by 'C', yielding an unknown channel layout
with the specified number of channels. Note that not all channel layout specification
strings support unknown channel layouts.
• a channel layout mask, in hexadecimal starting with "0x" (see the "AV_CH_*" macros in
libavutil/channel_layout.h.
Before libavutil version 53 the trailing character "c" to specify a number of channels was
optional, but now it is required, while a channel layout mask can also be specified as a
decimal number (if and only if not followed by "c" or "C").
See also the function "av_channel_layout_from_string" defined in
libavutil/channel_layout.h.
EXPRESSION EVALUATION
When evaluating an arithmetic expression, FFmpeg uses an internal formula evaluator,
implemented through the libavutil/eval.h interface.
An expression may contain unary, binary operators, constants, and functions.
Two expressions expr1 and expr2 can be combined to form another expression "expr1;expr2".
expr1 and expr2 are evaluated in turn, and the new expression evaluates to the value of
expr2.
The following binary operators are available: "+", "-", "*", "/", "^".
The following unary operators are available: "+", "-".
Some internal variables can be used to store and load intermediary results. They can be
accessed using the "ld" and "st" functions with an index argument varying from 0 to 9 to
specify which internal variable to access.
The following functions are available:
abs(x)
Compute absolute value of x.
acos(x)
Compute arccosine of x.
asin(x)
Compute arcsine of x.
atan(x)
Compute arctangent of x.
atan2(y, x)
Compute principal value of the arc tangent of y/x.
between(x, min, max)
Return 1 if x is greater than or equal to min and lesser than or equal to max, 0
otherwise.
bitand(x, y)
bitor(x, y)
Compute bitwise and/or operation on x and y.
The results of the evaluation of x and y are converted to integers before executing
the bitwise operation.
Note that both the conversion to integer and the conversion back to floating point can
lose precision. Beware of unexpected results for large numbers (usually 2^53 and
larger).
ceil(expr)
Round the value of expression expr upwards to the nearest integer. For example,
"ceil(1.5)" is "2.0".
clip(x, min, max)
Return the value of x clipped between min and max.
cos(x)
Compute cosine of x.
cosh(x)
Compute hyperbolic cosine of x.
eq(x, y)
Return 1 if x and y are equivalent, 0 otherwise.
exp(x)
Compute exponential of x (with base "e", the Euler's number).
floor(expr)
Round the value of expression expr downwards to the nearest integer. For example,
"floor(-1.5)" is "-2.0".
gauss(x)
Compute Gauss function of x, corresponding to "exp(-x*x/2) / sqrt(2*PI)".
gcd(x, y)
Return the greatest common divisor of x and y. If both x and y are 0 or either or both
are less than zero then behavior is undefined.
gt(x, y)
Return 1 if x is greater than y, 0 otherwise.
gte(x, y)
Return 1 if x is greater than or equal to y, 0 otherwise.
hypot(x, y)
This function is similar to the C function with the same name; it returns "sqrt(x*x +
y*y)", the length of the hypotenuse of a right triangle with sides of length x and y,
or the distance of the point (x, y) from the origin.
if(x, y)
Evaluate x, and if the result is non-zero return the result of the evaluation of y,
return 0 otherwise.
if(x, y, z)
Evaluate x, and if the result is non-zero return the evaluation result of y, otherwise
the evaluation result of z.
ifnot(x, y)
Evaluate x, and if the result is zero return the result of the evaluation of y, return
0 otherwise.
ifnot(x, y, z)
Evaluate x, and if the result is zero return the evaluation result of y, otherwise the
evaluation result of z.
isinf(x)
Return 1.0 if x is +/-INFINITY, 0.0 otherwise.
isnan(x)
Return 1.0 if x is NAN, 0.0 otherwise.
ld(idx)
Load the value of the internal variable with index idx, which was previously stored
with st(idx, expr). The function returns the loaded value.
lerp(x, y, z)
Return linear interpolation between x and y by amount of z.
log(x)
Compute natural logarithm of x.
lt(x, y)
Return 1 if x is lesser than y, 0 otherwise.
lte(x, y)
Return 1 if x is lesser than or equal to y, 0 otherwise.
max(x, y)
Return the maximum between x and y.
min(x, y)
Return the minimum between x and y.
mod(x, y)
Compute the remainder of division of x by y.
not(expr)
Return 1.0 if expr is zero, 0.0 otherwise.
pow(x, y)
Compute the power of x elevated y, it is equivalent to "(x)^(y)".
print(t)
print(t, l)
Print the value of expression t with loglevel l. If l is not specified then a default
log level is used. Return the value of the expression printed.
random(idx)
Return a pseudo random value between 0.0 and 1.0. idx is the index of the internal
variable used to save the seed/state, which can be previously stored with st(idx).
To initialize the seed, you need to store the seed value as a 64-bit unsigned integer
in the internal variable with index idx.
For example, to store the seed with value 42 in the internal variable with index 0 and
print a few random values:
st(0,42); print(random(0)); print(random(0)); print(random(0))
randomi(idx, min, max)
Return a pseudo random value in the interval between min and max. idx is the index of
the internal variable which will be used to save the seed/state, which can be
previously stored with st(idx).
To initialize the seed, you need to store the seed value as a 64-bit unsigned integer
in the internal variable with index idx.
root(expr, max)
Find an input value for which the function represented by expr with argument ld(0) is
0 in the interval 0..max.
The expression in expr must denote a continuous function or the result is undefined.
ld(0) is used to represent the function input value, which means that the given
expression will be evaluated multiple times with various input values that the
expression can access through ld(0). When the expression evaluates to 0 then the
corresponding input value will be returned.
round(expr)
Round the value of expression expr to the nearest integer. For example, "round(1.5)"
is "2.0".
sgn(x)
Compute sign of x.
sin(x)
Compute sine of x.
sinh(x)
Compute hyperbolic sine of x.
sqrt(expr)
Compute the square root of expr. This is equivalent to "(expr)^.5".
squish(x)
Compute expression "1/(1 + exp(4*x))".
st(idx, expr)
Store the value of the expression expr in an internal variable. idx specifies the
index of the variable where to store the value, and it is a value ranging from 0 to 9.
The function returns the value stored in the internal variable.
The stored value can be retrieved with ld(var).
Note: variables are currently not shared between expressions.
tan(x)
Compute tangent of x.
tanh(x)
Compute hyperbolic tangent of x.
taylor(expr, x)
taylor(expr, x, idx)
Evaluate a Taylor series at x, given an expression representing the ld(idx)-th
derivative of a function at 0.
When the series does not converge the result is undefined.
ld(idx) is used to represent the derivative order in expr, which means that the given
expression will be evaluated multiple times with various input values that the
expression can access through ld(idx). If idx is not specified then 0 is assumed.
Note, when you have the derivatives at y instead of 0, "taylor(expr, x-y)" can be
used.
time(0)
Return the current (wallclock) time in seconds.
trunc(expr)
Round the value of expression expr towards zero to the nearest integer. For example,
"trunc(-1.5)" is "-1.0".
while(cond, expr)
Evaluate expression expr while the expression cond is non-zero, and returns the value
of the last expr evaluation, or NAN if cond was always false.
The following constants are available:
PI area of the unit disc, approximately 3.14
E exp(1) (Euler's number), approximately 2.718
PHI golden ratio (1+sqrt(5))/2, approximately 1.618
Assuming that an expression is considered "true" if it has a non-zero value, note that:
"*" works like AND
"+" works like OR
For example the construct:
if (A AND B) then C
is equivalent to:
if(A*B, C)
In your C code, you can extend the list of unary and binary functions, and define
recognized constants, so that they are available for your expressions.
The evaluator also recognizes the International System unit prefixes. If 'i' is appended
after the prefix, binary prefixes are used, which are based on powers of 1024 instead of
powers of 1000. The 'B' postfix multiplies the value by 8, and can be appended after a
unit prefix or used alone. This allows using for example 'KB', 'MiB', 'G' and 'B' as
number postfix.
The list of available International System prefixes follows, with indication of the
corresponding powers of 10 and of 2.
y 10^-24 / 2^-80
z 10^-21 / 2^-70
a 10^-18 / 2^-60
f 10^-15 / 2^-50
p 10^-12 / 2^-40
n 10^-9 / 2^-30
u 10^-6 / 2^-20
m 10^-3 / 2^-10
c 10^-2
d 10^-1
h 10^2
k 10^3 / 2^10
K 10^3 / 2^10
M 10^6 / 2^20
G 10^9 / 2^30
T 10^12 / 2^40
P 10^15 / 2^50
E 10^18 / 2^60
Z 10^21 / 2^70
Y 10^24 / 2^80
CODEC OPTIONS
libavcodec provides some generic global options, which can be set on all the encoders and
decoders. In addition, each codec may support so-called private options, which are
specific for a given codec.
Sometimes, a global option may only affect a specific kind of codec, and may be
nonsensical or ignored by another, so you need to be aware of the meaning of the specified
options. Also some options are meant only for decoding or encoding.
Options may be set by specifying -option value in the FFmpeg tools, or by setting the
value explicitly in the "AVCodecContext" options or using the libavutil/opt.h API for
programmatic use.
The list of supported options follow:
b integer (encoding,audio,video)
Set bitrate in bits/s. Default value is 200K.
ab integer (encoding,audio)
Set audio bitrate (in bits/s). Default value is 128K.
bt integer (encoding,video)
Set video bitrate tolerance (in bits/s). In 1-pass mode, bitrate tolerance specifies
how far ratecontrol is willing to deviate from the target average bitrate value. This
is not related to min/max bitrate. Lowering tolerance too much has an adverse effect
on quality.
flags flags (decoding/encoding,audio,video,subtitles)
Set generic flags.
Possible values:
mv4 Use four motion vector by macroblock (mpeg4).
qpel
Use 1/4 pel motion compensation.
loop
Use loop filter.
qscale
Use fixed qscale.
pass1
Use internal 2pass ratecontrol in first pass mode.
pass2
Use internal 2pass ratecontrol in second pass mode.
gray
Only decode/encode grayscale.
psnr
Set error[?] variables during encoding.
truncated
Input bitstream might be randomly truncated.
drop_changed
Don't output frames whose parameters differ from first decoded frame in stream.
Error AVERROR_INPUT_CHANGED is returned when a frame is dropped.
ildct
Use interlaced DCT.
low_delay
Force low delay.
global_header
Place global headers in extradata instead of every keyframe.
bitexact
Only write platform-, build- and time-independent data. (except (I)DCT). This
ensures that file and data checksums are reproducible and match between platforms.
Its primary use is for regression testing.
aic Apply H263 advanced intra coding / mpeg4 ac prediction.
ilme
Apply interlaced motion estimation.
cgop
Use closed gop.
output_corrupt
Output even potentially corrupted frames.
time_base rational number
Set codec time base.
It is the fundamental unit of time (in seconds) in terms of which frame timestamps are
represented. For fixed-fps content, timebase should be "1 / frame_rate" and timestamp
increments should be identically 1.
g integer (encoding,video)
Set the group of picture (GOP) size. Default value is 12.
ar integer (decoding/encoding,audio)
Set audio sampling rate (in Hz).
ac integer (decoding/encoding,audio)
Set number of audio channels.
cutoff integer (encoding,audio)
Set cutoff bandwidth. (Supported only by selected encoders, see their respective
documentation sections.)
frame_size integer (encoding,audio)
Set audio frame size.
Each submitted frame except the last must contain exactly frame_size samples per
channel. May be 0 when the codec has CODEC_CAP_VARIABLE_FRAME_SIZE set, in that case
the frame size is not restricted. It is set by some decoders to indicate constant
frame size.
frame_number integer
Set the frame number.
delay integer
qcomp float (encoding,video)
Set video quantizer scale compression (VBR). It is used as a constant in the
ratecontrol equation. Recommended range for default rc_eq: 0.0-1.0.
qblur float (encoding,video)
Set video quantizer scale blur (VBR).
qmin integer (encoding,video)
Set min video quantizer scale (VBR). Must be included between -1 and 69, default value
is 2.
qmax integer (encoding,video)
Set max video quantizer scale (VBR). Must be included between -1 and 1024, default
value is 31.
qdiff integer (encoding,video)
Set max difference between the quantizer scale (VBR).
bf integer (encoding,video)
Set max number of B frames between non-B-frames.
Must be an integer between -1 and 16. 0 means that B-frames are disabled. If a value
of -1 is used, it will choose an automatic value depending on the encoder.
Default value is 0.
b_qfactor float (encoding,video)
Set qp factor between P and B frames.
codec_tag integer
bug flags (decoding,video)
Workaround not auto detected encoder bugs.
Possible values:
autodetect
xvid_ilace
Xvid interlacing bug (autodetected if fourcc==XVIX)
ump4
(autodetected if fourcc==UMP4)
no_padding
padding bug (autodetected)
amv
qpel_chroma
std_qpel
old standard qpel (autodetected per fourcc/version)
qpel_chroma2
direct_blocksize
direct-qpel-blocksize bug (autodetected per fourcc/version)
edge
edge padding bug (autodetected per fourcc/version)
hpel_chroma
dc_clip
ms Workaround various bugs in microsoft broken decoders.
trunc
trancated frames
strict integer (decoding/encoding,audio,video)
Specify how strictly to follow the standards.
Possible values:
very
strictly conform to an older more strict version of the spec or reference software
strict
strictly conform to all the things in the spec no matter what consequences
normal
unofficial
allow unofficial extensions
experimental
allow non standardized experimental things, experimental (unfinished/work in
progress/not well tested) decoders and encoders. Note: experimental decoders can
pose a security risk, do not use this for decoding untrusted input.
b_qoffset float (encoding,video)
Set QP offset between P and B frames.
err_detect flags (decoding,audio,video)
Set error detection flags.
Possible values:
crccheck
verify embedded CRCs
bitstream
detect bitstream specification deviations
buffer
detect improper bitstream length
explode
abort decoding on minor error detection
ignore_err
ignore decoding errors, and continue decoding. This is useful if you want to
analyze the content of a video and thus want everything to be decoded no matter
what. This option will not result in a video that is pleasing to watch in case of
errors.
careful
consider things that violate the spec and have not been seen in the wild as errors
compliant
consider all spec non compliancies as errors
aggressive
consider things that a sane encoder should not do as an error
has_b_frames integer
block_align integer
rc_override_count integer
maxrate integer (encoding,audio,video)
Set max bitrate tolerance (in bits/s). Requires bufsize to be set.
minrate integer (encoding,audio,video)
Set min bitrate tolerance (in bits/s). Most useful in setting up a CBR encode. It is
of little use elsewise.
bufsize integer (encoding,audio,video)
Set ratecontrol buffer size (in bits).
i_qfactor float (encoding,video)
Set QP factor between P and I frames.
i_qoffset float (encoding,video)
Set QP offset between P and I frames.
dct integer (encoding,video)
Set DCT algorithm.
Possible values:
auto
autoselect a good one (default)
fastint
fast integer
int accurate integer
mmx
altivec
faan
floating point AAN DCT
lumi_mask float (encoding,video)
Compress bright areas stronger than medium ones.
tcplx_mask float (encoding,video)
Set temporal complexity masking.
scplx_mask float (encoding,video)
Set spatial complexity masking.
p_mask float (encoding,video)
Set inter masking.
dark_mask float (encoding,video)
Compress dark areas stronger than medium ones.
idct integer (decoding/encoding,video)
Select IDCT implementation.
Possible values:
auto
int
simple
simplemmx
simpleauto
Automatically pick a IDCT compatible with the simple one
arm
altivec
sh4
simplearm
simplearmv5te
simplearmv6
simpleneon
xvid
faani
floating point AAN IDCT
slice_count integer
ec flags (decoding,video)
Set error concealment strategy.
Possible values:
guess_mvs
iterative motion vector (MV) search (slow)
deblock
use strong deblock filter for damaged MBs
favor_inter
favor predicting from the previous frame instead of the current
bits_per_coded_sample integer
aspect rational number (encoding,video)
Set sample aspect ratio.
sar rational number (encoding,video)
Set sample aspect ratio. Alias to aspect.
debug flags (decoding/encoding,audio,video,subtitles)
Print specific debug info.
Possible values:
pict
picture info
rc rate control
bitstream
mb_type
macroblock (MB) type
qp per-block quantization parameter (QP)
dct_coeff
green_metadata
display complexity metadata for the upcoming frame, GoP or for a given duration.
skip
startcode
er error recognition
mmco
memory management control operations (H.264)
bugs
buffers
picture buffer allocations
thread_ops
threading operations
nomc
skip motion compensation
cmp integer (encoding,video)
Set full pel me compare function.
Possible values:
sad sum of absolute differences, fast (default)
sse sum of squared errors
satd
sum of absolute Hadamard transformed differences
dct sum of absolute DCT transformed differences
psnr
sum of squared quantization errors (avoid, low quality)
bit number of bits needed for the block
rd rate distortion optimal, slow
zero
0
vsad
sum of absolute vertical differences
vsse
sum of squared vertical differences
nsse
noise preserving sum of squared differences
w53 5/3 wavelet, only used in snow
w97 9/7 wavelet, only used in snow
dctmax
chroma
subcmp integer (encoding,video)
Set sub pel me compare function.
Possible values:
sad sum of absolute differences, fast (default)
sse sum of squared errors
satd
sum of absolute Hadamard transformed differences
dct sum of absolute DCT transformed differences
psnr
sum of squared quantization errors (avoid, low quality)
bit number of bits needed for the block
rd rate distortion optimal, slow
zero
0
vsad
sum of absolute vertical differences
vsse
sum of squared vertical differences
nsse
noise preserving sum of squared differences
w53 5/3 wavelet, only used in snow
w97 9/7 wavelet, only used in snow
dctmax
chroma
mbcmp integer (encoding,video)
Set macroblock compare function.
Possible values:
sad sum of absolute differences, fast (default)
sse sum of squared errors
satd
sum of absolute Hadamard transformed differences
dct sum of absolute DCT transformed differences
psnr
sum of squared quantization errors (avoid, low quality)
bit number of bits needed for the block
rd rate distortion optimal, slow
zero
0
vsad
sum of absolute vertical differences
vsse
sum of squared vertical differences
nsse
noise preserving sum of squared differences
w53 5/3 wavelet, only used in snow
w97 9/7 wavelet, only used in snow
dctmax
chroma
ildctcmp integer (encoding,video)
Set interlaced dct compare function.
Possible values:
sad sum of absolute differences, fast (default)
sse sum of squared errors
satd
sum of absolute Hadamard transformed differences
dct sum of absolute DCT transformed differences
psnr
sum of squared quantization errors (avoid, low quality)
bit number of bits needed for the block
rd rate distortion optimal, slow
zero
0
vsad
sum of absolute vertical differences
vsse
sum of squared vertical differences
nsse
noise preserving sum of squared differences
w53 5/3 wavelet, only used in snow
w97 9/7 wavelet, only used in snow
dctmax
chroma
dia_size integer (encoding,video)
Set diamond type & size for motion estimation.
(1024, INT_MAX)
full motion estimation(slowest)
(768, 1024]
umh motion estimation
(512, 768]
hex motion estimation
(256, 512]
l2s diamond motion estimation
[2,256]
var diamond motion estimation
(-1, 2)
small diamond motion estimation
-1 funny diamond motion estimation
(INT_MIN, -1)
sab diamond motion estimation
last_pred integer (encoding,video)
Set amount of motion predictors from the previous frame.
precmp integer (encoding,video)
Set pre motion estimation compare function.
Possible values:
sad sum of absolute differences, fast (default)
sse sum of squared errors
satd
sum of absolute Hadamard transformed differences
dct sum of absolute DCT transformed differences
psnr
sum of squared quantization errors (avoid, low quality)
bit number of bits needed for the block
rd rate distortion optimal, slow
zero
0
vsad
sum of absolute vertical differences
vsse
sum of squared vertical differences
nsse
noise preserving sum of squared differences
w53 5/3 wavelet, only used in snow
w97 9/7 wavelet, only used in snow
dctmax
chroma
pre_dia_size integer (encoding,video)
Set diamond type & size for motion estimation pre-pass.
subq integer (encoding,video)
Set sub pel motion estimation quality.
me_range integer (encoding,video)
Set limit motion vectors range (1023 for DivX player).
global_quality integer (encoding,audio,video)
slice_flags integer
mbd integer (encoding,video)
Set macroblock decision algorithm (high quality mode).
Possible values:
simple
use mbcmp (default)
bits
use fewest bits
rd use best rate distortion
rc_init_occupancy integer (encoding,video)
Set number of bits which should be loaded into the rc buffer before decoding starts.
flags2 flags (decoding/encoding,audio,video,subtitles)
Possible values:
fast
Allow non spec compliant speedup tricks.
noout
Skip bitstream encoding.
ignorecrop
Ignore cropping information from sps.
local_header
Place global headers at every keyframe instead of in extradata.
chunks
Frame data might be split into multiple chunks.
showall
Show all frames before the first keyframe.
export_mvs
Export motion vectors into frame side-data (see "AV_FRAME_DATA_MOTION_VECTORS")
for codecs that support it. See also doc/examples/export_mvs.c.
skip_manual
Do not skip samples and export skip information as frame side data.
ass_ro_flush_noop
Do not reset ASS ReadOrder field on flush.
icc_profiles
Generate/parse embedded ICC profiles from/to colorimetry tags.
export_side_data flags (decoding/encoding,audio,video,subtitles)
Possible values:
mvs Export motion vectors into frame side-data (see "AV_FRAME_DATA_MOTION_VECTORS")
for codecs that support it. See also doc/examples/export_mvs.c.
prft
Export encoder Producer Reference Time into packet side-data (see
"AV_PKT_DATA_PRFT") for codecs that support it.
venc_params
Export video encoding parameters through frame side data (see
"AV_FRAME_DATA_VIDEO_ENC_PARAMS") for codecs that support it. At present, those
are H.264 and VP9.
film_grain
Export film grain parameters through frame side data (see
"AV_FRAME_DATA_FILM_GRAIN_PARAMS"). Supported at present by AV1 decoders.
threads integer (decoding/encoding,video)
Set the number of threads to be used, in case the selected codec implementation
supports multi-threading.
Possible values:
auto, 0
automatically select the number of threads to set
Default value is auto.
dc integer (encoding,video)
Set intra_dc_precision.
nssew integer (encoding,video)
Set nsse weight.
skip_top integer (decoding,video)
Set number of macroblock rows at the top which are skipped.
skip_bottom integer (decoding,video)
Set number of macroblock rows at the bottom which are skipped.
profile integer (encoding,audio,video)
Set encoder codec profile. Default value is unknown. Encoder specific profiles are
documented in the relevant encoder documentation.
level integer (encoding,audio,video)
Set the encoder level. This level depends on the specific codec, and might correspond
to the profile level. It is set by default to unknown.
Possible values:
unknown
lowres integer (decoding,audio,video)
Decode at 1= 1/2, 2=1/4, 3=1/8 resolutions.
mblmin integer (encoding,video)
Set min macroblock lagrange factor (VBR).
mblmax integer (encoding,video)
Set max macroblock lagrange factor (VBR).
skip_loop_filter integer (decoding,video)
skip_idct integer (decoding,video)
skip_frame integer (decoding,video)
Make decoder discard processing depending on the frame type selected by the option
value.
skip_loop_filter skips frame loop filtering, skip_idct skips frame
IDCT/dequantization, skip_frame skips decoding.
Possible values:
none
Discard no frame.
default
Discard useless frames like 0-sized frames.
noref
Discard all non-reference frames.
bidir
Discard all bidirectional frames.
nokey
Discard all frames excepts keyframes.
nointra
Discard all frames except I frames.
all Discard all frames.
Default value is default.
bidir_refine integer (encoding,video)
Refine the two motion vectors used in bidirectional macroblocks.
keyint_min integer (encoding,video)
Set minimum interval between IDR-frames.
refs integer (encoding,video)
Set reference frames to consider for motion compensation.
trellis integer (encoding,audio,video)
Set rate-distortion optimal quantization.
mv0_threshold integer (encoding,video)
compression_level integer (encoding,audio,video)
bits_per_raw_sample integer
channel_layout integer (decoding/encoding,audio)
See the Channel Layout section in the ffmpeg-utils(1) manual for the required syntax.
rc_max_vbv_use float (encoding,video)
rc_min_vbv_use float (encoding,video)
color_primaries integer (decoding/encoding,video)
Possible values:
bt709
BT.709
bt470m
BT.470 M
bt470bg
BT.470 BG
smpte170m
SMPTE 170 M
smpte240m
SMPTE 240 M
film
Film
bt2020
BT.2020
smpte428
smpte428_1
SMPTE ST 428-1
smpte431
SMPTE 431-2
smpte432
SMPTE 432-1
jedec-p22
JEDEC P22
color_trc integer (decoding/encoding,video)
Possible values:
bt709
BT.709
gamma22
BT.470 M
gamma28
BT.470 BG
smpte170m
SMPTE 170 M
smpte240m
SMPTE 240 M
linear
Linear
log
log100
Log
log_sqrt
log316
Log square root
iec61966_2_4
iec61966-2-4
IEC 61966-2-4
bt1361
bt1361e
BT.1361
iec61966_2_1
iec61966-2-1
IEC 61966-2-1
bt2020_10
bt2020_10bit
BT.2020 - 10 bit
bt2020_12
bt2020_12bit
BT.2020 - 12 bit
smpte2084
SMPTE ST 2084
smpte428
smpte428_1
SMPTE ST 428-1
arib-std-b67
ARIB STD-B67
colorspace integer (decoding/encoding,video)
Possible values:
rgb RGB
bt709
BT.709
fcc FCC
bt470bg
BT.470 BG
smpte170m
SMPTE 170 M
smpte240m
SMPTE 240 M
ycocg
YCOCG
bt2020nc
bt2020_ncl
BT.2020 NCL
bt2020c
bt2020_cl
BT.2020 CL
smpte2085
SMPTE 2085
chroma-derived-nc
Chroma-derived NCL
chroma-derived-c
Chroma-derived CL
ictcp
ICtCp
color_range integer (decoding/encoding,video)
If used as input parameter, it serves as a hint to the decoder, which color_range the
input has. Possible values:
tv
mpeg
limited
MPEG (219*2^(n-8))
pc
jpeg
full
JPEG (2^n-1)
chroma_sample_location integer (decoding/encoding,video)
Possible values:
left
center
topleft
top
bottomleft
bottom
log_level_offset integer
Set the log level offset.
slices integer (encoding,video)
Number of slices, used in parallelized encoding.
thread_type flags (decoding/encoding,video)
Select which multithreading methods to use.
Use of frame will increase decoding delay by one frame per thread, so clients which
cannot provide future frames should not use it.
Possible values:
slice
Decode more than one part of a single frame at once.
Multithreading using slices works only when the video was encoded with slices.
frame
Decode more than one frame at once.
Default value is slice+frame.
audio_service_type integer (encoding,audio)
Set audio service type.
Possible values:
ma Main Audio Service
ef Effects
vi Visually Impaired
hi Hearing Impaired
di Dialogue
co Commentary
em Emergency
vo Voice Over
ka Karaoke
request_sample_fmt sample_fmt (decoding,audio)
Set sample format audio decoders should prefer. Default value is "none".
pkt_timebase rational number
sub_charenc encoding (decoding,subtitles)
Set the input subtitles character encoding.
field_order field_order (video)
Set/override the field order of the video. Possible values:
progressive
Progressive video
tt Interlaced video, top field coded and displayed first
bb Interlaced video, bottom field coded and displayed first
tb Interlaced video, top coded first, bottom displayed first
bt Interlaced video, bottom coded first, top displayed first
skip_alpha bool (decoding,video)
Set to 1 to disable processing alpha (transparency). This works like the gray flag in
the flags option which skips chroma information instead of alpha. Default is 0.
codec_whitelist list (input)
"," separated list of allowed decoders. By default all are allowed.
dump_separator string (input)
Separator used to separate the fields printed on the command line about the Stream
parameters. For example, to separate the fields with newlines and indentation:
ffprobe -dump_separator "
" -i ~/videos/matrixbench_mpeg2.mpg
max_pixels integer (decoding/encoding,video)
Maximum number of pixels per image. This value can be used to avoid out of memory
failures due to large images.
apply_cropping bool (decoding,video)
Enable cropping if cropping parameters are multiples of the required alignment for the
left and top parameters. If the alignment is not met the cropping will be partially
applied to maintain alignment. Default is 1 (enabled). Note: The required alignment
depends on if "AV_CODEC_FLAG_UNALIGNED" is set and the CPU. "AV_CODEC_FLAG_UNALIGNED"
cannot be changed from the command line. Also hardware decoders will not apply
left/top Cropping.
DECODERS
Decoders are configured elements in FFmpeg which allow the decoding of multimedia streams.
When you configure your FFmpeg build, all the supported native decoders are enabled by
default. Decoders requiring an external library must be enabled manually via the
corresponding "--enable-lib" option. You can list all available decoders using the
configure option "--list-decoders".
You can disable all the decoders with the configure option "--disable-decoders" and
selectively enable / disable single decoders with the options "--enable-decoder=DECODER" /
"--disable-decoder=DECODER".
The option "-decoders" of the ff* tools will display the list of enabled decoders.
VIDEO DECODERS
A description of some of the currently available video decoders follows.
av1
AOMedia Video 1 (AV1) decoder.
Options
operating_point
Select an operating point of a scalable AV1 bitstream (0 - 31). Default is 0.
hevc
HEVC (AKA ITU-T H.265 or ISO/IEC 23008-2) decoder.
The decoder supports MV-HEVC multiview streams with at most two views. Views to be output
are selected by supplying a list of view IDs to the decoder (the view_ids option). This
option may be set either statically before decoder init, or from the get_format() callback
- useful for the case when the view count or IDs change dynamically during decoding.
Only the base layer is decoded by default.
Note that if you are using the "ffmpeg" CLI tool, you should be using view specifiers as
documented in its manual, rather than the options documented here.
Options
view_ids (MV-HEVC)
Specify a list of view IDs that should be output. This option can also be set to a
single '-1', which will cause all views defined in the VPS to be decoded and output.
view_ids_available (MV-HEVC)
This option may be read by the caller to retrieve an array of view IDs available in
the active VPS. The array is empty for single-layer video.
The value of this option is guaranteed to be accurate when read from the get_format()
callback. It may also be set at other times (e.g. after opening the decoder), but the
value is informational only and may be incorrect (e.g. when the stream contains
multiple distinct VPS NALUs).
view_pos_available (MV-HEVC)
This option may be read by the caller to retrieve an array of view positions (left,
right, or unspecified) available in the active VPS, as "AVStereo3DView" values. When
the array is available, its elements apply to the corresponding elements of
view_ids_available, i.e. "view_pos_available[i]" contains the position of view with
ID "view_ids_available[i]".
Same validity restrictions as for view_ids_available apply to this option.
rawvideo
Raw video decoder.
This decoder decodes rawvideo streams.
Options
top top_field_first
Specify the assumed field type of the input video.
-1 the video is assumed to be progressive (default)
0 bottom-field-first is assumed
1 top-field-first is assumed
libdav1d
dav1d AV1 decoder.
libdav1d allows libavcodec to decode the AOMedia Video 1 (AV1) codec. Requires the
presence of the libdav1d headers and library during configuration. You need to explicitly
configure the build with "--enable-libdav1d".
Options
The following options are supported by the libdav1d wrapper.
framethreads
Set amount of frame threads to use during decoding. The default value is 0
(autodetect). This option is deprecated for libdav1d >= 1.0 and will be removed in
the future. Use the option "max_frame_delay" and the global option "threads" instead.
tilethreads
Set amount of tile threads to use during decoding. The default value is 0
(autodetect). This option is deprecated for libdav1d >= 1.0 and will be removed in
the future. Use the global option "threads" instead.
max_frame_delay
Set max amount of frames the decoder may buffer internally. The default value is 0
(autodetect).
filmgrain
Apply film grain to the decoded video if present in the bitstream. Defaults to the
internal default of the library. This option is deprecated and will be removed in the
future. See the global option "export_side_data" to export Film Grain parameters
instead of applying it.
oppoint
Select an operating point of a scalable AV1 bitstream (0 - 31). Defaults to the
internal default of the library.
alllayers
Output all spatial layers of a scalable AV1 bitstream. The default value is false.
libdavs2
AVS2-P2/IEEE1857.4 video decoder wrapper.
This decoder allows libavcodec to decode AVS2 streams with davs2 library.
libuavs3d
AVS3-P2/IEEE1857.10 video decoder.
libuavs3d allows libavcodec to decode AVS3 streams. Requires the presence of the
libuavs3d headers and library during configuration. You need to explicitly configure the
build with "--enable-libuavs3d".
Options
The following option is supported by the libuavs3d wrapper.
frame_threads
Set amount of frame threads to use during decoding. The default value is 0
(autodetect).
libxevd
eXtra-fast Essential Video Decoder (XEVD) MPEG-5 EVC decoder wrapper.
This decoder requires the presence of the libxevd headers and library during
configuration. You need to explicitly configure the build with --enable-libxevd.
The xevd project website is at <https://github.com/mpeg5/xevd>.
Options
The following options are supported by the libxevd wrapper. The xevd-equivalent options
or values are listed in parentheses for easy migration.
To get a more accurate and extensive documentation of the libxevd options, invoke the
command "xevd_app --help" or consult the libxevd documentation.
threads (threads)
Force to use a specific number of threads
QSV Decoders
The family of Intel QuickSync Video decoders (VC1, MPEG-2, H.264, HEVC, JPEG/MJPEG, VP8,
VP9, AV1, VVC).
Common Options
The following options are supported by all qsv decoders.
async_depth
Internal parallelization depth, the higher the value the higher the latency.
gpu_copy
A GPU-accelerated copy between video and system memory
default
on
off
HEVC Options
Extra options for hevc_qsv.
load_plugin
A user plugin to load in an internal session
none
hevc_sw
hevc_hw
load_plugins
A :-separate list of hexadecimal plugin UIDs to load in an internal session
v210
Uncompressed 4:2:2 10-bit decoder.
Options
custom_stride
Set the line size of the v210 data in bytes. The default value is 0 (autodetect). You
can use the special -1 value for a strideless v210 as seen in BOXX files.
AUDIO DECODERS
A description of some of the currently available audio decoders follows.
ac3
AC-3 audio decoder.
This decoder implements part of ATSC A/52:2010 and ETSI TS 102 366, as well as the
undocumented RealAudio 3 (a.k.a. dnet).
AC-3 Decoder Options
-drc_scale value
Dynamic Range Scale Factor. The factor to apply to dynamic range values from the AC-3
stream. This factor is applied exponentially. The default value is 1. There are 3
notable scale factor ranges:
drc_scale == 0
DRC disabled. Produces full range audio.
0 < drc_scale <= 1
DRC enabled. Applies a fraction of the stream DRC value. Audio reproduction is
between full range and full compression.
drc_scale > 1
DRC enabled. Applies drc_scale asymmetrically. Loud sounds are fully compressed.
Soft sounds are enhanced.
flac
FLAC audio decoder.
This decoder aims to implement the complete FLAC specification from Xiph.
FLAC Decoder options
-use_buggy_lpc
The lavc FLAC encoder used to produce buggy streams with high lpc values (like the
default value). This option makes it possible to decode such streams correctly by
using lavc's old buggy lpc logic for decoding.
ffwavesynth
Internal wave synthesizer.
This decoder generates wave patterns according to predefined sequences. Its use is purely
internal and the format of the data it accepts is not publicly documented.
libcelt
libcelt decoder wrapper.
libcelt allows libavcodec to decode the Xiph CELT ultra-low delay audio codec. Requires
the presence of the libcelt headers and library during configuration. You need to
explicitly configure the build with "--enable-libcelt".
libgsm
libgsm decoder wrapper.
libgsm allows libavcodec to decode the GSM full rate audio codec. Requires the presence of
the libgsm headers and library during configuration. You need to explicitly configure the
build with "--enable-libgsm".
This decoder supports both the ordinary GSM and the Microsoft variant.
libilbc
libilbc decoder wrapper.
libilbc allows libavcodec to decode the Internet Low Bitrate Codec (iLBC) audio codec.
Requires the presence of the libilbc headers and library during configuration. You need to
explicitly configure the build with "--enable-libilbc".
Options
The following option is supported by the libilbc wrapper.
enhance
Enable the enhancement of the decoded audio when set to 1. The default value is 0
(disabled).
libopencore-amrnb
libopencore-amrnb decoder wrapper.
libopencore-amrnb allows libavcodec to decode the Adaptive Multi-Rate Narrowband audio
codec. Using it requires the presence of the libopencore-amrnb headers and library during
configuration. You need to explicitly configure the build with
"--enable-libopencore-amrnb".
An FFmpeg native decoder for AMR-NB exists, so users can decode AMR-NB without this
library.
libopencore-amrwb
libopencore-amrwb decoder wrapper.
libopencore-amrwb allows libavcodec to decode the Adaptive Multi-Rate Wideband audio
codec. Using it requires the presence of the libopencore-amrwb headers and library during
configuration. You need to explicitly configure the build with
"--enable-libopencore-amrwb".
An FFmpeg native decoder for AMR-WB exists, so users can decode AMR-WB without this
library.
libopus
libopus decoder wrapper.
libopus allows libavcodec to decode the Opus Interactive Audio Codec. Requires the
presence of the libopus headers and library during configuration. You need to explicitly
configure the build with "--enable-libopus".
An FFmpeg native decoder for Opus exists, so users can decode Opus without this library.
SUBTITLES DECODERS
libaribb24
ARIB STD-B24 caption decoder.
Implements profiles A and C of the ARIB STD-B24 standard.
libaribb24 Decoder Options
-aribb24-base-path path
Sets the base path for the libaribb24 library. This is utilized for reading of
configuration files (for custom unicode conversions), and for dumping of non-text
symbols as images under that location.
Unset by default.
-aribb24-skip-ruby-text boolean
Tells the decoder wrapper to skip text blocks that contain half-height ruby text.
Enabled by default.
libaribcaption
Yet another ARIB STD-B24 caption decoder using external libaribcaption library.
Implements profiles A and C of the Japanse ARIB STD-B24 standard, Brazilian ABNT NBR
15606-1, and Philippines version of ISDB-T.
Requires the presence of the libaribcaption headers and library
(<https://github.com/xqq/libaribcaption>) during configuration. You need to explicitly
configure the build with "--enable-libaribcaption". If both libaribb24 and libaribcaption
are enabled, libaribcaption decoder precedes.
libaribcaption Decoder Options
-sub_type subtitle_type
Specifies the format of the decoded subtitles.
bitmap
Graphical image.
ass ASS formatted text.
text
Simple text based output without formatting.
The default is ass as same as libaribb24 decoder. Some present players (e.g., mpv)
expect ASS format for ARIB caption.
-caption_encoding encoding_scheme
Specifies the encoding scheme of input subtitle text.
auto
Automatically detect text encoding (default).
jis 8bit-char JIS encoding defined in ARIB STD B24. This encoding used in Japan for
ISDB captions.
utf8
UTF-8 encoding defined in ARIB STD B24. This encoding is used in Philippines for
ISDB-T captions.
latin
Latin character encoding defined in ABNT NBR 15606-1. This encoding is used in
South America for SBTVD / ISDB-Tb captions.
-font font_name[,font_name2,...]
Specify comma-separated list of font family names to be used for bitmap or ass type
subtitle rendering. Only first font name is used for ass type subtitle.
If not specified, use internaly defined default font family.
-ass_single_rect boolean
ARIB STD-B24 specifies that some captions may be displayed at different positions at a
time (multi-rectangle subtitle). Since some players (e.g., old mpv) can't handle
multiple ASS rectangles in a single AVSubtitle, or multiple ASS rectangles of
indeterminate duration with the same start timestamp, this option can change the
behavior so that all the texts are displayed in a single ASS rectangle.
The default is false.
If your player cannot handle AVSubtitles with multiple ASS rectangles properly, set
this option to true or define ASS_SINGLE_RECT=1 to change default behavior at
compilation.
-force_outline_text boolean
Specify whether always render outline text for all characters regardless of the
indication by charactor style.
The default is false.
-outline_width number (0.0 - 3.0)
Specify width for outline text, in dots (relative).
The default is 1.5.
-ignore_background boolean
Specify whether to ignore background color rendering.
The default is false.
-ignore_ruby boolean
Specify whether to ignore rendering for ruby-like (furigana) characters.
The default is false.
-replace_drcs boolean
Specify whether to render replaced DRCS characters as Unicode characters.
The default is true.
-replace_msz_ascii boolean
Specify whether to replace MSZ (Middle Size; half width) fullwidth alphanumerics with
halfwidth alphanumerics.
The default is true.
-replace_msz_japanese boolean
Specify whether to replace some MSZ (Middle Size; half width) fullwidth japanese
special characters with halfwidth ones.
The default is true.
-replace_msz_glyph boolean
Specify whether to replace MSZ (Middle Size; half width) characters with halfwidth
glyphs if the fonts supports it. This option works under FreeType or DirectWrite
renderer with Adobe-Japan1 compliant fonts. e.g., IBM Plex Sans JP, Morisawa BIZ
UDGothic, Morisawa BIZ UDMincho, Yu Gothic, Yu Mincho, and Meiryo.
The default is true.
-canvas_size image_size
Specify the resolution of the canvas to render subtitles to; usually, this should be
frame size of input video. This only applies when "-subtitle_type" is set to bitmap.
The libaribcaption decoder assumes input frame size for bitmap rendering as below:
1. PROFILE_A : 1440 x 1080 with SAR (PAR) 4:3
2. PROFILE_C : 320 x 180 with SAR (PAR) 1:1
If actual frame size of input video does not match above assumption, the rendered
captions may be distorted. To make the captions undistorted, add "-canvas_size"
option to specify actual input video size.
Note that the "-canvas_size" option is not required for video with different size but
same aspect ratio. In such cases, the caption will be stretched or shrunk to actual
video size if "-canvas_size" option is not specified. If "-canvas_size" option is
specified with different size, the caption will be stretched or shrunk as specified
size with calculated SAR.
libaribcaption decoder usage examples
Display MPEG-TS file with ARIB subtitle by "ffplay" tool:
ffplay -sub_type bitmap MPEG.TS
Display MPEG-TS file with input frame size 1920x1080 by "ffplay" tool:
ffplay -sub_type bitmap -canvas_size 1920x1080 MPEG.TS
Embed ARIB subtitle in transcoded video:
ffmpeg -sub_type bitmap -i src.m2t -filter_complex "[0:v][0:s]overlay" -vcodec h264 dest.mp4
dvbsub
Options
compute_clut
-2 Compute clut once if no matching CLUT is in the stream.
-1 Compute clut if no matching CLUT is in the stream.
0 Never compute CLUT
1 Always compute CLUT and override the one provided in the stream.
dvb_substream
Selects the dvb substream, or all substreams if -1 which is default.
dvdsub
This codec decodes the bitmap subtitles used in DVDs; the same subtitles can also be found
in VobSub file pairs and in some Matroska files.
Options
palette
Specify the global palette used by the bitmaps. When stored in VobSub, the palette is
normally specified in the index file; in Matroska, the palette is stored in the codec
extra-data in the same format as in VobSub. In DVDs, the palette is stored in the IFO
file, and therefore not available when reading from dumped VOB files.
The format for this option is a string containing 16 24-bits hexadecimal numbers
(without 0x prefix) separated by commas, for example "0d00ee, ee450d, 101010, eaeaea,
0ce60b, ec14ed, ebff0b, 0d617a, 7b7b7b, d1d1d1, 7b2a0e, 0d950c, 0f007b, cf0dec,
cfa80c, 7c127b".
ifo_palette
Specify the IFO file from which the global palette is obtained. (experimental)
forced_subs_only
Only decode subtitle entries marked as forced. Some titles have forced and non-forced
subtitles in the same track. Setting this flag to 1 will only keep the forced
subtitles. Default value is 0.
libzvbi-teletext
Libzvbi allows libavcodec to decode DVB teletext pages and DVB teletext subtitles.
Requires the presence of the libzvbi headers and library during configuration. You need to
explicitly configure the build with "--enable-libzvbi".
Options
txt_page
List of teletext page numbers to decode. Pages that do not match the specified list
are dropped. You may use the special "*" string to match all pages, or "subtitle" to
match all subtitle pages. Default value is *.
txt_default_region
Set default character set used for decoding, a value between 0 and 87 (see ETS 300
706, Section 15, Table 32). Default value is -1, which does not override the libzvbi
default. This option is needed for some legacy level 1.0 transmissions which cannot
signal the proper charset.
txt_chop_top
Discards the top teletext line. Default value is 1.
txt_format
Specifies the format of the decoded subtitles.
bitmap
The default format, you should use this for teletext pages, because certain
graphics and colors cannot be expressed in simple text or even ASS.
text
Simple text based output without formatting.
ass Formatted ASS output, subtitle pages and teletext pages are returned in different
styles, subtitle pages are stripped down to text, but an effort is made to keep
the text alignment and the formatting.
txt_left
X offset of generated bitmaps, default is 0.
txt_top
Y offset of generated bitmaps, default is 0.
txt_chop_spaces
Chops leading and trailing spaces and removes empty lines from the generated text.
This option is useful for teletext based subtitles where empty spaces may be present
at the start or at the end of the lines or empty lines may be present between the
subtitle lines because of double-sized teletext characters. Default value is 1.
txt_duration
Sets the display duration of the decoded teletext pages or subtitles in milliseconds.
Default value is -1 which means infinity or until the next subtitle event comes.
txt_transparent
Force transparent background of the generated teletext bitmaps. Default value is 0
which means an opaque background.
txt_opacity
Sets the opacity (0-255) of the teletext background. If txt_transparent is not set, it
only affects characters between a start box and an end box, typically subtitles.
Default value is 0 if txt_transparent is set, 255 otherwise.
BITSTREAM FILTERS
When you configure your FFmpeg build, all the supported bitstream filters are enabled by
default. You can list all available ones using the configure option "--list-bsfs".
You can disable all the bitstream filters using the configure option "--disable-bsfs", and
selectively enable any bitstream filter using the option "--enable-bsf=BSF", or you can
disable a particular bitstream filter using the option "--disable-bsf=BSF".
The option "-bsfs" of the ff* tools will display the list of all the supported bitstream
filters included in your build.
The ff* tools have a -bsf option applied per stream, taking a comma-separated list of
filters, whose parameters follow the filter name after a '='.
ffmpeg -i INPUT -c:v copy -bsf:v filter1[=opt1=str1:opt2=str2][,filter2] OUTPUT
Below is a description of the currently available bitstream filters, with their
parameters, if any.
aac_adtstoasc
Convert MPEG-2/4 AAC ADTS to an MPEG-4 Audio Specific Configuration bitstream.
This filter creates an MPEG-4 AudioSpecificConfig from an MPEG-2/4 ADTS header and removes
the ADTS header.
This filter is required for example when copying an AAC stream from a raw ADTS AAC or an
MPEG-TS container to MP4A-LATM, to an FLV file, or to MOV/MP4 files and related formats
such as 3GP or M4A. Please note that it is auto-inserted for MP4A-LATM and MOV/MP4 and
related formats.
av1_metadata
Modify metadata embedded in an AV1 stream.
td Insert or remove temporal delimiter OBUs in all temporal units of the stream.
insert
Insert a TD at the beginning of every TU which does not already have one.
remove
Remove the TD from the beginning of every TU which has one.
color_primaries
transfer_characteristics
matrix_coefficients
Set the color description fields in the stream (see AV1 section 6.4.2).
color_range
Set the color range in the stream (see AV1 section 6.4.2; note that this cannot be set
for streams using BT.709 primaries, sRGB transfer characteristic and identity (RGB)
matrix coefficients).
tv Limited range.
pc Full range.
chroma_sample_position
Set the chroma sample location in the stream (see AV1 section 6.4.2). This can only
be set for 4:2:0 streams.
vertical
Left position (matching the default in MPEG-2 and H.264).
colocated
Top-left position.
tick_rate
Set the tick rate (time_scale / num_units_in_display_tick) in the timing info in the
sequence header.
num_ticks_per_picture
Set the number of ticks in each picture, to indicate that the stream has a fixed
framerate. Ignored if tick_rate is not also set.
delete_padding
Deletes Padding OBUs.
chomp
Remove zero padding at the end of a packet.
dca_core
Extract the core from a DCA/DTS stream, dropping extensions such as DTS-HD.
dovi_rpu
Manipulate Dolby Vision metadata in a HEVC/AV1 bitstream, optionally enabling metadata
compression.
strip
If enabled, strip all Dolby Vision metadata (configuration record + RPU data blocks)
from the stream.
compression
Which compression level to enable.
none
No metadata compression.
limited
Limited metadata compression scheme. Should be compatible with most devices. This
is the default.
extended
Extended metadata compression. Devices are not required to support this. Note that
this level currently behaves the same as limited in libavcodec.
dump_extra
Add extradata to the beginning of the filtered packets except when said packets already
exactly begin with the extradata that is intended to be added.
freq
The additional argument specifies which packets should be filtered. It accepts the
values:
k
keyframe
add extradata to all key packets
e
all add extradata to all packets
If not specified it is assumed k.
For example the following ffmpeg command forces a global header (thus disabling individual
packet headers) in the H.264 packets generated by the "libx264" encoder, but corrects them
by adding the header stored in extradata to the key packets:
ffmpeg -i INPUT -map 0 -flags:v +global_header -c:v libx264 -bsf:v dump_extra out.ts
dv_error_marker
Blocks in DV which are marked as damaged are replaced by blocks of the specified color.
color
The color to replace damaged blocks by
sta A 16 bit mask which specifies which of the 16 possible error status values are to be
replaced by colored blocks. 0xFFFE is the default which replaces all non 0 error
status values.
ok No error, no concealment
err Error, No concealment
res Reserved
notok
Error or concealment
notres
Not reserved
Aa, Ba, Ca, Ab, Bb, Cb, A, B, C, a, b, erri, erru
The specific error status code
see page 44-46 or section 5.5 of
<http://web.archive.org/web/20060927044735/http://www.smpte.org/smpte_store/standards/pdf/s314m.pdf>
eac3_core
Extract the core from a E-AC-3 stream, dropping extra channels.
extract_extradata
Extract the in-band extradata.
Certain codecs allow the long-term headers (e.g. MPEG-2 sequence headers, or H.264/HEVC
(VPS/)SPS/PPS) to be transmitted either "in-band" (i.e. as a part of the bitstream
containing the coded frames) or "out of band" (e.g. on the container level). This latter
form is called "extradata" in FFmpeg terminology.
This bitstream filter detects the in-band headers and makes them available as extradata.
remove
When this option is enabled, the long-term headers are removed from the bitstream
after extraction.
filter_units
Remove units with types in or not in a given set from the stream.
pass_types
List of unit types or ranges of unit types to pass through while removing all others.
This is specified as a '|'-separated list of unit type values or ranges of values with
'-'.
remove_types
Identical to pass_types, except the units in the given set removed and all others
passed through.
The types used by pass_types and remove_types correspond to NAL unit types (nal_unit_type)
in H.264, HEVC and H.266 (see Table 7-1 in the H.264 and HEVC specifications or Table 5 in
the H.266 specification), to marker values for JPEG (without 0xFF prefix) and to start
codes without start code prefix (i.e. the byte following the 0x000001) for MPEG-2. For
VP8 and VP9, every unit has type zero.
Extradata is unchanged by this transformation, but note that if the stream contains inline
parameter sets then the output may be unusable if they are removed.
For example, to remove all non-VCL NAL units from an H.264 stream:
ffmpeg -i INPUT -c:v copy -bsf:v 'filter_units=pass_types=1-5' OUTPUT
To remove all AUDs, SEI and filler from an H.265 stream:
ffmpeg -i INPUT -c:v copy -bsf:v 'filter_units=remove_types=35|38-40' OUTPUT
To remove all user data from a MPEG-2 stream, including Closed Captions:
ffmpeg -i INPUT -c:v copy -bsf:v 'filter_units=remove_types=178' OUTPUT
To remove all SEI from a H264 stream, including Closed Captions:
ffmpeg -i INPUT -c:v copy -bsf:v 'filter_units=remove_types=6' OUTPUT
To remove all prefix and suffix SEI from a HEVC stream, including Closed Captions and
dynamic HDR:
ffmpeg -i INPUT -c:v copy -bsf:v 'filter_units=remove_types=39|40' OUTPUT
hapqa_extract
Extract Rgb or Alpha part of an HAPQA file, without recompression, in order to create an
HAPQ or an HAPAlphaOnly file.
texture
Specifies the texture to keep.
color
alpha
Convert HAPQA to HAPQ
ffmpeg -i hapqa_inputfile.mov -c copy -bsf:v hapqa_extract=texture=color -tag:v HapY -metadata:s:v:0 encoder="HAPQ" hapq_file.mov
Convert HAPQA to HAPAlphaOnly
ffmpeg -i hapqa_inputfile.mov -c copy -bsf:v hapqa_extract=texture=alpha -tag:v HapA -metadata:s:v:0 encoder="HAPAlpha Only" hapalphaonly_file.mov
h264_metadata
Modify metadata embedded in an H.264 stream.
aud Insert or remove AUD NAL units in all access units of the stream.
pass
insert
remove
Default is pass.
sample_aspect_ratio
Set the sample aspect ratio of the stream in the VUI parameters. See H.264 table E-1.
overscan_appropriate_flag
Set whether the stream is suitable for display using overscan or not (see H.264
section E.2.1).
video_format
video_full_range_flag
Set the video format in the stream (see H.264 section E.2.1 and table E-2).
colour_primaries
transfer_characteristics
matrix_coefficients
Set the colour description in the stream (see H.264 section E.2.1 and tables E-3, E-4
and E-5).
chroma_sample_loc_type
Set the chroma sample location in the stream (see H.264 section E.2.1 and figure E-1).
tick_rate
Set the tick rate (time_scale / num_units_in_tick) in the VUI parameters. This is the
smallest time unit representable in the stream, and in many cases represents the field
rate of the stream (double the frame rate).
fixed_frame_rate_flag
Set whether the stream has fixed framerate - typically this indicates that the
framerate is exactly half the tick rate, but the exact meaning is dependent on
interlacing and the picture structure (see H.264 section E.2.1 and table E-6).
zero_new_constraint_set_flags
Zero constraint_set4_flag and constraint_set5_flag in the SPS. These bits were
reserved in a previous version of the H.264 spec, and thus some hardware decoders
require these to be zero. The result of zeroing this is still a valid bitstream.
crop_left
crop_right
crop_top
crop_bottom
Set the frame cropping offsets in the SPS. These values will replace the current ones
if the stream is already cropped.
These fields are set in pixels. Note that some sizes may not be representable if the
chroma is subsampled or the stream is interlaced (see H.264 section 7.4.2.1.1).
sei_user_data
Insert a string as SEI unregistered user data. The argument must be of the form
UUID+string, where the UUID is as hex digits possibly separated by hyphens, and the
string can be anything.
For example, 086f3693-b7b3-4f2c-9653-21492feee5b8+hello will insert the string
``hello'' associated with the given UUID.
delete_filler
Deletes both filler NAL units and filler SEI messages.
display_orientation
Insert, extract or remove Display orientation SEI messages. See H.264 section D.1.27
and D.2.27 for syntax and semantics.
pass
insert
remove
extract
Default is pass.
Insert mode works in conjunction with "rotate" and "flip" options. Any pre-existing
Display orientation messages will be removed in insert or remove mode. Extract mode
attaches the display matrix to the packet as side data.
rotate
Set rotation in display orientation SEI (anticlockwise angle in degrees). Range is
-360 to +360. Default is NaN.
flip
Set flip in display orientation SEI.
horizontal
vertical
Default is unset.
level
Set the level in the SPS. Refer to H.264 section A.3 and tables A-1 to A-5.
The argument must be the name of a level (for example, 4.2), a level_idc value (for
example, 42), or the special name auto indicating that the filter should attempt to
guess the level from the input stream properties.
h264_mp4toannexb
Convert an H.264 bitstream from length prefixed mode to start code prefixed mode (as
defined in the Annex B of the ITU-T H.264 specification).
This is required by some streaming formats, typically the MPEG-2 transport stream format
(muxer "mpegts").
For example to remux an MP4 file containing an H.264 stream to mpegts format with ffmpeg,
you can use the command:
ffmpeg -i INPUT.mp4 -codec copy -bsf:v h264_mp4toannexb OUTPUT.ts
Please note that this filter is auto-inserted for MPEG-TS (muxer "mpegts") and raw H.264
(muxer "h264") output formats.
h264_redundant_pps
This applies a specific fixup to some Blu-ray streams which contain redundant PPSs
modifying irrelevant parameters of the stream which confuse other transformations which
require correct extradata.
hevc_metadata
Modify metadata embedded in an HEVC stream.
aud Insert or remove AUD NAL units in all access units of the stream.
insert
remove
sample_aspect_ratio
Set the sample aspect ratio in the stream in the VUI parameters.
video_format
video_full_range_flag
Set the video format in the stream (see H.265 section E.3.1 and table E.2).
colour_primaries
transfer_characteristics
matrix_coefficients
Set the colour description in the stream (see H.265 section E.3.1 and tables E.3, E.4
and E.5).
chroma_sample_loc_type
Set the chroma sample location in the stream (see H.265 section E.3.1 and figure E.1).
tick_rate
Set the tick rate in the VPS and VUI parameters (time_scale / num_units_in_tick).
Combined with num_ticks_poc_diff_one, this can set a constant framerate in the stream.
Note that it is likely to be overridden by container parameters when the stream is in
a container.
num_ticks_poc_diff_one
Set poc_proportional_to_timing_flag in VPS and VUI and use this value to set
num_ticks_poc_diff_one_minus1 (see H.265 sections 7.4.3.1 and E.3.1). Ignored if
tick_rate is not also set.
crop_left
crop_right
crop_top
crop_bottom
Set the conformance window cropping offsets in the SPS. These values will replace the
current ones if the stream is already cropped.
These fields are set in pixels. Note that some sizes may not be representable if the
chroma is subsampled (H.265 section 7.4.3.2.1).
width
height
Set width and height after crop.
level
Set the level in the VPS and SPS. See H.265 section A.4 and tables A.6 and A.7.
The argument must be the name of a level (for example, 5.1), a general_level_idc value
(for example, 153 for level 5.1), or the special name auto indicating that the filter
should attempt to guess the level from the input stream properties.
hevc_mp4toannexb
Convert an HEVC/H.265 bitstream from length prefixed mode to start code prefixed mode (as
defined in the Annex B of the ITU-T H.265 specification).
This is required by some streaming formats, typically the MPEG-2 transport stream format
(muxer "mpegts").
For example to remux an MP4 file containing an HEVC stream to mpegts format with ffmpeg,
you can use the command:
ffmpeg -i INPUT.mp4 -codec copy -bsf:v hevc_mp4toannexb OUTPUT.ts
Please note that this filter is auto-inserted for MPEG-TS (muxer "mpegts") and raw
HEVC/H.265 (muxer "h265" or "hevc") output formats.
imxdump
Modifies the bitstream to fit in MOV and to be usable by the Final Cut Pro decoder. This
filter only applies to the mpeg2video codec, and is likely not needed for Final Cut Pro 7
and newer with the appropriate -tag:v.
For example, to remux 30 MB/sec NTSC IMX to MOV:
ffmpeg -i input.mxf -c copy -bsf:v imxdump -tag:v mx3n output.mov
mjpeg2jpeg
Convert MJPEG/AVI1 packets to full JPEG/JFIF packets.
MJPEG is a video codec wherein each video frame is essentially a JPEG image. The
individual frames can be extracted without loss, e.g. by
ffmpeg -i ../some_mjpeg.avi -c:v copy frames_%d.jpg
Unfortunately, these chunks are incomplete JPEG images, because they lack the DHT segment
required for decoding. Quoting from
<http://www.digitalpreservation.gov/formats/fdd/fdd000063.shtml>:
Avery Lee, writing in the rec.video.desktop newsgroup in 2001, commented that "MJPEG, or
at least the MJPEG in AVIs having the MJPG fourcc, is restricted JPEG with a fixed -- and
*omitted* -- Huffman table. The JPEG must be YCbCr colorspace, it must be 4:2:2, and it
must use basic Huffman encoding, not arithmetic or progressive. . . . You can indeed
extract the MJPEG frames and decode them with a regular JPEG decoder, but you have to
prepend the DHT segment to them, or else the decoder won't have any idea how to decompress
the data. The exact table necessary is given in the OpenDML spec."
This bitstream filter patches the header of frames extracted from an MJPEG stream
(carrying the AVI1 header ID and lacking a DHT segment) to produce fully qualified JPEG
images.
ffmpeg -i mjpeg-movie.avi -c:v copy -bsf:v mjpeg2jpeg frame_%d.jpg
exiftran -i -9 frame*.jpg
ffmpeg -i frame_%d.jpg -c:v copy rotated.avi
mjpegadump
Add an MJPEG A header to the bitstream, to enable decoding by Quicktime.
mov2textsub
Extract a representable text file from MOV subtitles, stripping the metadata header from
each subtitle packet.
See also the text2movsub filter.
mpeg2_metadata
Modify metadata embedded in an MPEG-2 stream.
display_aspect_ratio
Set the display aspect ratio in the stream.
The following fixed values are supported:
4/3
16/9
221/100
Any other value will result in square pixels being signalled instead (see H.262
section 6.3.3 and table 6-3).
frame_rate
Set the frame rate in the stream. This is constructed from a table of known values
combined with a small multiplier and divisor - if the supplied value is not exactly
representable, the nearest representable value will be used instead (see H.262 section
6.3.3 and table 6-4).
video_format
Set the video format in the stream (see H.262 section 6.3.6 and table 6-6).
colour_primaries
transfer_characteristics
matrix_coefficients
Set the colour description in the stream (see H.262 section 6.3.6 and tables 6-7, 6-8
and 6-9).
mpeg4_unpack_bframes
Unpack DivX-style packed B-frames.
DivX-style packed B-frames are not valid MPEG-4 and were only a workaround for the broken
Video for Windows subsystem. They use more space, can cause minor AV sync issues, require
more CPU power to decode (unless the player has some decoded picture queue to compensate
the 2,0,2,0 frame per packet style) and cause trouble if copied into a standard container
like mp4 or mpeg-ps/ts, because MPEG-4 decoders may not be able to decode them, since they
are not valid MPEG-4.
For example to fix an AVI file containing an MPEG-4 stream with DivX-style packed B-frames
using ffmpeg, you can use the command:
ffmpeg -i INPUT.avi -codec copy -bsf:v mpeg4_unpack_bframes OUTPUT.avi
noise
Damages the contents of packets or simply drops them without damaging the container. Can
be used for fuzzing or testing error resilience/concealment.
Parameters:
amount
Accepts an expression whose evaluation per-packet determines how often bytes in that
packet will be modified. A value below 0 will result in a variable frequency. Default
is 0 which results in no modification. However, if neither amount nor drop is
specified, amount will be set to -1. See below for accepted variables.
drop
Accepts an expression evaluated per-packet whose value determines whether that packet
is dropped. Evaluation to a positive value results in the packet being dropped.
Evaluation to a negative value results in a variable chance of it being dropped,
roughly inverse in proportion to the magnitude of the value. Default is 0 which
results in no drops. See below for accepted variables.
dropamount
Accepts a non-negative integer, which assigns a variable chance of it being dropped,
roughly inverse in proportion to the value. Default is 0 which results in no drops.
This option is kept for backwards compatibility and is equivalent to setting drop to a
negative value with the same magnitude i.e. "dropamount=4" is the same as "drop=-4".
Ignored if drop is also specified.
Both "amount" and "drop" accept expressions containing the following variables:
n The index of the packet, starting from zero.
tb The timebase for packet timestamps.
pts Packet presentation timestamp.
dts Packet decoding timestamp.
nopts
Constant representing AV_NOPTS_VALUE.
startpts
First non-AV_NOPTS_VALUE PTS seen in the stream.
startdts
First non-AV_NOPTS_VALUE DTS seen in the stream.
duration
d Packet duration, in timebase units.
pos Packet position in input; may be -1 when unknown or not set.
size
Packet size, in bytes.
key Whether packet is marked as a keyframe.
state
A pseudo random integer, primarily derived from the content of packet payload.
Examples
Apply modification to every byte but don't drop any packets.
ffmpeg -i INPUT -c copy -bsf noise=1 output.mkv
Drop every video packet not marked as a keyframe after timestamp 30s but do not modify any
of the remaining packets.
ffmpeg -i INPUT -c copy -bsf:v noise=drop='gt(t\,30)*not(key)' output.mkv
Drop one second of audio every 10 seconds and add some random noise to the rest.
ffmpeg -i INPUT -c copy -bsf:a noise=amount=-1:drop='between(mod(t\,10)\,9\,10)' output.mkv
null
This bitstream filter passes the packets through unchanged.
pcm_rechunk
Repacketize PCM audio to a fixed number of samples per packet or a fixed packet rate per
second. This is similar to the asetnsamples audio filter but works on audio packets
instead of audio frames.
nb_out_samples, n
Set the number of samples per each output audio packet. The number is intended as the
number of samples per each channel. Default value is 1024.
pad, p
If set to 1, the filter will pad the last audio packet with silence, so that it will
contain the same number of samples (or roughly the same number of samples, see
frame_rate) as the previous ones. Default value is 1.
frame_rate, r
This option makes the filter output a fixed number of packets per second instead of a
fixed number of samples per packet. If the audio sample rate is not divisible by the
frame rate then the number of samples will not be constant but will vary slightly so
that each packet will start as close to the frame boundary as possible. Using this
option has precedence over nb_out_samples.
You can generate the well known 1602-1601-1602-1601-1602 pattern of 48kHz audio for NTSC
frame rate using the frame_rate option.
ffmpeg -f lavfi -i sine=r=48000:d=1 -c pcm_s16le -bsf pcm_rechunk=r=30000/1001 -f framecrc -
pgs_frame_merge
Merge a sequence of PGS Subtitle segments ending with an "end of display set" segment into
a single packet.
This is required by some containers that support PGS subtitles (muxer "matroska").
prores_metadata
Modify color property metadata embedded in prores stream.
color_primaries
Set the color primaries. Available values are:
auto
Keep the same color primaries property (default).
unknown
bt709
bt470bg
BT601 625
smpte170m
BT601 525
bt2020
smpte431
DCI P3
smpte432
P3 D65
transfer_characteristics
Set the color transfer. Available values are:
auto
Keep the same transfer characteristics property (default).
unknown
bt709
BT 601, BT 709, BT 2020
smpte2084
SMPTE ST 2084
arib-std-b67
ARIB STD-B67
matrix_coefficients
Set the matrix coefficient. Available values are:
auto
Keep the same colorspace property (default).
unknown
bt709
smpte170m
BT 601
bt2020nc
Set Rec709 colorspace for each frame of the file
ffmpeg -i INPUT -c copy -bsf:v prores_metadata=color_primaries=bt709:color_trc=bt709:colorspace=bt709 output.mov
Set Hybrid Log-Gamma parameters for each frame of the file
ffmpeg -i INPUT -c copy -bsf:v prores_metadata=color_primaries=bt2020:color_trc=arib-std-b67:colorspace=bt2020nc output.mov
remove_extra
Remove extradata from packets.
It accepts the following parameter:
freq
Set which frame types to remove extradata from.
k Remove extradata from non-keyframes only.
keyframe
Remove extradata from keyframes only.
e, all
Remove extradata from all frames.
setts
Set PTS and DTS in packets.
It accepts the following parameters:
ts
pts
dts Set expressions for PTS, DTS or both.
duration
Set expression for duration.
time_base
Set output time base.
The expressions are evaluated through the eval API and can contain the following
constants:
N The count of the input packet. Starting from 0.
TS The demux timestamp in input in case of "ts" or "dts" option or presentation timestamp
in case of "pts" option.
POS The original position in the file of the packet, or undefined if undefined for the
current packet
DTS The demux timestamp in input.
PTS The presentation timestamp in input.
DURATION
The duration in input.
STARTDTS
The DTS of the first packet.
STARTPTS
The PTS of the first packet.
PREV_INDTS
The previous input DTS.
PREV_INPTS
The previous input PTS.
PREV_INDURATION
The previous input duration.
PREV_OUTDTS
The previous output DTS.
PREV_OUTPTS
The previous output PTS.
PREV_OUTDURATION
The previous output duration.
NEXT_DTS
The next input DTS.
NEXT_PTS
The next input PTS.
NEXT_DURATION
The next input duration.
TB The timebase of stream packet belongs.
TB_OUT
The output timebase.
SR The sample rate of stream packet belongs.
NOPTS
The AV_NOPTS_VALUE constant.
For example, to set PTS equal to DTS (not recommended if B-frames are involved):
ffmpeg -i INPUT -c:a copy -bsf:a setts=pts=DTS out.mkv
showinfo
Log basic packet information. Mainly useful for testing, debugging, and development.
text2movsub
Convert text subtitles to MOV subtitles (as used by the "mov_text" codec) with metadata
headers.
See also the mov2textsub filter.
trace_headers
Log trace output containing all syntax elements in the coded stream headers (everything
above the level of individual coded blocks). This can be useful for debugging low-level
stream issues.
Supports AV1, H.264, H.265, (M)JPEG, MPEG-2 and VP9, but depending on the build only a
subset of these may be available.
truehd_core
Extract the core from a TrueHD stream, dropping ATMOS data.
vp9_metadata
Modify metadata embedded in a VP9 stream.
color_space
Set the color space value in the frame header. Note that any frame set to RGB will be
implicitly set to PC range and that RGB is incompatible with profiles 0 and 2.
unknown
bt601
bt709
smpte170
smpte240
bt2020
rgb
color_range
Set the color range value in the frame header. Note that any value imposed by the
color space will take precedence over this value.
tv
pc
vp9_superframe
Merge VP9 invisible (alt-ref) frames back into VP9 superframes. This fixes merging of
split/segmented VP9 streams where the alt-ref frame was split from its visible
counterpart.
vp9_superframe_split
Split VP9 superframes into single frames.
vp9_raw_reorder
Given a VP9 stream with correct timestamps but possibly out of order, insert additional
show-existing-frame packets to correct the ordering.
FORMAT OPTIONS
The libavformat library provides some generic global options, which can be set on all the
muxers and demuxers. In addition each muxer or demuxer may support so-called private
options, which are specific for that component.
Options may be set by specifying -option value in the FFmpeg tools, or by setting the
value explicitly in the "AVFormatContext" options or using the libavutil/opt.h API for
programmatic use.
The list of supported options follows:
avioflags flags (input/output)
Possible values:
direct
Reduce buffering.
probesize integer (input)
Set probing size in bytes, i.e. the size of the data to analyze to get stream
information. A higher value will enable detecting more information in case it is
dispersed into the stream, but will increase latency. Must be an integer not lesser
than 32. It is 5000000 by default.
max_probe_packets integer (input)
Set the maximum number of buffered packets when probing a codec. Default is 2500
packets.
packetsize integer (output)
Set packet size.
fflags flags
Set format flags. Some are implemented for a limited number of formats.
Possible values for input files:
discardcorrupt
Discard corrupted packets.
fastseek
Enable fast, but inaccurate seeks for some formats.
genpts
Generate missing PTS if DTS is present.
igndts
Ignore DTS if PTS is also set. In case the PTS is set, the DTS value is set to
NOPTS. This is ignored when the "nofillin" flag is set.
ignidx
Ignore index.
nobuffer
Reduce the latency introduced by buffering during initial input streams analysis.
nofillin
Do not fill in missing values in packet fields that can be exactly calculated.
noparse
Disable AVParsers, this needs "+nofillin" too.
sortdts
Try to interleave output packets by DTS. At present, available only for AVIs with
an index.
Possible values for output files:
autobsf
Automatically apply bitstream filters as required by the output format. Enabled by
default.
bitexact
Only write platform-, build- and time-independent data. This ensures that file
and data checksums are reproducible and match between platforms. Its primary use
is for regression testing.
flush_packets
Write out packets immediately.
shortest
Stop muxing at the end of the shortest stream. It may be needed to increase
max_interleave_delta to avoid flushing the longer streams before EOF.
seek2any integer (input)
Allow seeking to non-keyframes on demuxer level when supported if set to 1. Default
is 0.
analyzeduration integer (input)
Specify how many microseconds are analyzed to probe the input. A higher value will
enable detecting more accurate information, but will increase latency. It defaults to
5,000,000 microseconds = 5 seconds.
cryptokey hexadecimal string (input)
Set decryption key.
indexmem integer (input)
Set max memory used for timestamp index (per stream).
rtbufsize integer (input)
Set max memory used for buffering real-time frames.
fdebug flags (input/output)
Print specific debug info.
Possible values:
ts
max_delay integer (input/output)
Set maximum muxing or demuxing delay in microseconds.
fpsprobesize integer (input)
Set number of frames used to probe fps.
audio_preload integer (output)
Set microseconds by which audio packets should be interleaved earlier.
chunk_duration integer (output)
Set microseconds for each chunk.
chunk_size integer (output)
Set size in bytes for each chunk.
err_detect, f_err_detect flags (input)
Set error detection flags. "f_err_detect" is deprecated and should be used only via
the ffmpeg tool.
Possible values:
crccheck
Verify embedded CRCs.
bitstream
Detect bitstream specification deviations.
buffer
Detect improper bitstream length.
explode
Abort decoding on minor error detection.
careful
Consider things that violate the spec and have not been seen in the wild as
errors.
compliant
Consider all spec non compliancies as errors.
aggressive
Consider things that a sane encoder should not do as an error.
max_interleave_delta integer (output)
Set maximum buffering duration for interleaving. The duration is expressed in
microseconds, and defaults to 10000000 (10 seconds).
To ensure all the streams are interleaved correctly, libavformat will wait until it
has at least one packet for each stream before actually writing any packets to the
output file. When some streams are "sparse" (i.e. there are large gaps between
successive packets), this can result in excessive buffering.
This field specifies the maximum difference between the timestamps of the first and
the last packet in the muxing queue, above which libavformat will output a packet
regardless of whether it has queued a packet for all the streams.
If set to 0, libavformat will continue buffering packets until it has a packet for
each stream, regardless of the maximum timestamp difference between the buffered
packets.
use_wallclock_as_timestamps integer (input)
Use wallclock as timestamps if set to 1. Default is 0.
avoid_negative_ts integer (output)
Possible values:
make_non_negative
Shift timestamps to make them non-negative. Also note that this affects only
leading negative timestamps, and not non-monotonic negative timestamps.
make_zero
Shift timestamps so that the first timestamp is 0.
auto (default)
Enables shifting when required by the target format.
disabled
Disables shifting of timestamp.
When shifting is enabled, all output timestamps are shifted by the same amount. Audio,
video, and subtitles desynching and relative timestamp differences are preserved
compared to how they would have been without shifting.
skip_initial_bytes integer (input)
Set number of bytes to skip before reading header and frames if set to 1. Default is
0.
correct_ts_overflow integer (input)
Correct single timestamp overflows if set to 1. Default is 1.
flush_packets integer (output)
Flush the underlying I/O stream after each packet. Default is -1 (auto), which means
that the underlying protocol will decide, 1 enables it, and has the effect of reducing
the latency, 0 disables it and may increase IO throughput in some cases.
output_ts_offset offset (output)
Set the output time offset.
offset must be a time duration specification, see the Time duration section in the
ffmpeg-utils(1) manual.
The offset is added by the muxer to the output timestamps.
Specifying a positive offset means that the corresponding streams are delayed bt the
time duration specified in offset. Default value is 0 (meaning that no offset is
applied).
format_whitelist list (input)
"," separated list of allowed demuxers. By default all are allowed.
dump_separator string (input)
Separator used to separate the fields printed on the command line about the Stream
parameters. For example, to separate the fields with newlines and indentation:
ffprobe -dump_separator "
" -i ~/videos/matrixbench_mpeg2.mpg
max_streams integer (input)
Specifies the maximum number of streams. This can be used to reject files that would
require too many resources due to a large number of streams.
skip_estimate_duration_from_pts bool (input)
Skip estimation of input duration if it requires an additional probing for PTS at end
of file. At present, applicable for MPEG-PS and MPEG-TS.
duration_probesize integer (input)
Set probing size, in bytes, for input duration estimation when it actually requires an
additional probing for PTS at end of file (at present: MPEG-PS and MPEG-TS). It is
aimed at users interested in better durations probing for itself, or indirectly
because using the concat demuxer, for example. The typical use case is an MPEG-TS CBR
with a high bitrate, high video buffering and ending cleaning with similar PTS for
video and audio: in such a scenario, the large physical gap between the last video
packet and the last audio packet makes it necessary to read many bytes in order to get
the video stream duration. Another use case is where the default probing behaviour
only reaches a single video frame which is not the last one of the stream due to frame
reordering, so the duration is not accurate. Setting this option has a performance
impact even for small files because the probing size is fixed. Default behaviour is a
general purpose trade-off, largely adaptive, but the probing size will not be extended
to get streams durations at all costs. Must be an integer not lesser than 1, or 0 for
default behaviour.
strict, f_strict integer (input/output)
Specify how strictly to follow the standards. "f_strict" is deprecated and should be
used only via the ffmpeg tool.
Possible values:
very
strictly conform to an older more strict version of the spec or reference software
strict
strictly conform to all the things in the spec no matter what consequences
normal
unofficial
allow unofficial extensions
experimental
allow non standardized experimental things, experimental (unfinished/work in
progress/not well tested) decoders and encoders. Note: experimental decoders can
pose a security risk, do not use this for decoding untrusted input.
Format stream specifiers
Format stream specifiers allow selection of one or more streams that match specific
properties.
The exact semantics of stream specifiers is defined by the
avformat_match_stream_specifier() function declared in the libavformat/avformat.h header
and documented in the Stream specifiers section in the ffmpeg(1) manual.
DEMUXERS
Demuxers are configured elements in FFmpeg that can read the multimedia streams from a
particular type of file.
When you configure your FFmpeg build, all the supported demuxers are enabled by default.
You can list all available ones using the configure option "--list-demuxers".
You can disable all the demuxers using the configure option "--disable-demuxers", and
selectively enable a single demuxer with the option "--enable-demuxer=DEMUXER", or disable
it with the option "--disable-demuxer=DEMUXER".
The option "-demuxers" of the ff* tools will display the list of enabled demuxers. Use
"-formats" to view a combined list of enabled demuxers and muxers.
The description of some of the currently available demuxers follows.
aa
Audible Format 2, 3, and 4 demuxer.
This demuxer is used to demux Audible Format 2, 3, and 4 (.aa) files.
aac
Raw Audio Data Transport Stream AAC demuxer.
This demuxer is used to demux an ADTS input containing a single AAC stream alongwith any
ID3v1/2 or APE tags in it.
apng
Animated Portable Network Graphics demuxer.
This demuxer is used to demux APNG files. All headers, but the PNG signature, up to (but
not including) the first fcTL chunk are transmitted as extradata. Frames are then split
as being all the chunks between two fcTL ones, or between the last fcTL and IEND chunks.
-ignore_loop bool
Ignore the loop variable in the file if set. Default is enabled.
-max_fps int
Maximum framerate in frames per second. Default of 0 imposes no limit.
-default_fps int
Default framerate in frames per second when none is specified in the file (0 meaning
as fast as possible). Default is 15.
asf
Advanced Systems Format demuxer.
This demuxer is used to demux ASF files and MMS network streams.
-no_resync_search bool
Do not try to resynchronize by looking for a certain optional start code.
concat
Virtual concatenation script demuxer.
This demuxer reads a list of files and other directives from a text file and demuxes them
one after the other, as if all their packets had been muxed together.
The timestamps in the files are adjusted so that the first file starts at 0 and each next
file starts where the previous one finishes. Note that it is done globally and may cause
gaps if all streams do not have exactly the same length.
All files must have the same streams (same codecs, same time base, etc.).
The duration of each file is used to adjust the timestamps of the next file: if the
duration is incorrect (because it was computed using the bit-rate or because the file is
truncated, for example), it can cause artifacts. The "duration" directive can be used to
override the duration stored in each file.
Syntax
The script is a text file in extended-ASCII, with one directive per line. Empty lines,
leading spaces and lines starting with '#' are ignored. The following directive is
recognized:
"file path"
Path to a file to read; special characters and spaces must be escaped with backslash
or single quotes.
All subsequent file-related directives apply to that file.
"ffconcat version 1.0"
Identify the script type and version.
To make FFmpeg recognize the format automatically, this directive must appear exactly
as is (no extra space or byte-order-mark) on the very first line of the script.
"duration dur"
Duration of the file. This information can be specified from the file; specifying it
here may be more efficient or help if the information from the file is not available
or accurate.
If the duration is set for all files, then it is possible to seek in the whole
concatenated video.
"inpoint timestamp"
In point of the file. When the demuxer opens the file it instantly seeks to the
specified timestamp. Seeking is done so that all streams can be presented successfully
at In point.
This directive works best with intra frame codecs, because for non-intra frame ones
you will usually get extra packets before the actual In point and the decoded content
will most likely contain frames before In point too.
For each file, packets before the file In point will have timestamps less than the
calculated start timestamp of the file (negative in case of the first file), and the
duration of the files (if not specified by the "duration" directive) will be reduced
based on their specified In point.
Because of potential packets before the specified In point, packet timestamps may
overlap between two concatenated files.
"outpoint timestamp"
Out point of the file. When the demuxer reaches the specified decoding timestamp in
any of the streams, it handles it as an end of file condition and skips the current
and all the remaining packets from all streams.
Out point is exclusive, which means that the demuxer will not output packets with a
decoding timestamp greater or equal to Out point.
This directive works best with intra frame codecs and formats where all streams are
tightly interleaved. For non-intra frame codecs you will usually get additional
packets with presentation timestamp after Out point therefore the decoded content will
most likely contain frames after Out point too. If your streams are not tightly
interleaved you may not get all the packets from all streams before Out point and you
may only will be able to decode the earliest stream until Out point.
The duration of the files (if not specified by the "duration" directive) will be
reduced based on their specified Out point.
"file_packet_metadata key=value"
Metadata of the packets of the file. The specified metadata will be set for each file
packet. You can specify this directive multiple times to add multiple metadata
entries. This directive is deprecated, use "file_packet_meta" instead.
"file_packet_meta key value"
Metadata of the packets of the file. The specified metadata will be set for each file
packet. You can specify this directive multiple times to add multiple metadata
entries.
"option key value"
Option to access, open and probe the file. Can be present multiple times.
"stream"
Introduce a stream in the virtual file. All subsequent stream-related directives
apply to the last introduced stream. Some streams properties must be set in order to
allow identifying the matching streams in the subfiles. If no streams are defined in
the script, the streams from the first file are copied.
"exact_stream_id id"
Set the id of the stream. If this directive is given, the string with the
corresponding id in the subfiles will be used. This is especially useful for MPEG-PS
(VOB) files, where the order of the streams is not reliable.
"stream_meta key value"
Metadata for the stream. Can be present multiple times.
"stream_codec value"
Codec for the stream.
"stream_extradata hex_string"
Extradata for the string, encoded in hexadecimal.
"chapter id start end"
Add a chapter. id is an unique identifier, possibly small and consecutive.
Options
This demuxer accepts the following option:
safe
If set to 1, reject unsafe file paths and directives. A file path is considered safe
if it does not contain a protocol specification and is relative and all components
only contain characters from the portable character set (letters, digits, period,
underscore and hyphen) and have no period at the beginning of a component.
If set to 0, any file name is accepted.
The default is 1.
auto_convert
If set to 1, try to perform automatic conversions on packet data to make the streams
concatenable. The default is 1.
Currently, the only conversion is adding the h264_mp4toannexb bitstream filter to
H.264 streams in MP4 format. This is necessary in particular if there are resolution
changes.
segment_time_metadata
If set to 1, every packet will contain the lavf.concat.start_time and the
lavf.concat.duration packet metadata values which are the start_time and the duration
of the respective file segments in the concatenated output expressed in microseconds.
The duration metadata is only set if it is known based on the concat file. The
default is 0.
Examples
• Use absolute filenames and include some comments:
# my first filename
file /mnt/share/file-1.wav
# my second filename including whitespace
file '/mnt/share/file 2.wav'
# my third filename including whitespace plus single quote
file '/mnt/share/file 3'\''.wav'
• Allow for input format auto-probing, use safe filenames and set the duration of the
first file:
ffconcat version 1.0
file file-1.wav
duration 20.0
file subdir/file-2.wav
dash
Dynamic Adaptive Streaming over HTTP demuxer.
This demuxer presents all AVStreams found in the manifest. By setting the discard flags
on AVStreams the caller can decide which streams to actually receive. Each stream mirrors
the "id" and "bandwidth" properties from the "<Representation>" as metadata keys named
"id" and "variant_bitrate" respectively.
Options
This demuxer accepts the following option:
cenc_decryption_key
16-byte key, in hex, to decrypt files encrypted using ISO Common Encryption
(CENC/AES-128 CTR; ISO/IEC 23001-7).
dvdvideo
DVD-Video demuxer, powered by libdvdnav and libdvdread.
Can directly ingest DVD titles, specifically sequential PGCs, into a conversion pipeline.
Menu assets, such as background video or audio, can also be demuxed given the menu's
coordinates (at best effort). Seeking is not supported at this time.
Block devices (DVD drives), ISO files, and directory structures are accepted. Activate
with "-f dvdvideo" in front of one of these inputs.
This demuxer does NOT have decryption code of any kind. You are on your own working with
encrypted DVDs, and should not expect support on the matter.
Underlying playback is handled by libdvdnav, and structure parsing by libdvdread. FFmpeg
must be built with GPL library support available as well as the configure switches
"--enable-libdvdnav" and "--enable-libdvdread".
You will need to provide either the desired "title number" or exact PGC/PG coordinates.
Many open-source DVD players and tools can aid in providing this information. If not
specified, the demuxer will default to title 1 which works for many discs. However, due
to the flexibility of the format, it is recommended to check manually. There are many
discs that are authored strangely or with invalid headers.
If the input is a real DVD drive, please note that there are some drives which may
silently fail on reading bad sectors from the disc, returning random bits instead which is
effectively corrupt data. This is especially prominent on aging or rotting discs. A
second pass and integrity checks would be needed to detect the corruption. This is not an
FFmpeg issue.
Background
DVD-Video is not a directly accessible, linear container format in the traditional sense.
Instead, it allows for complex and programmatic playback of carefully muxed MPEG-PS
streams that are stored in headerless VOB files. To the end-user, these streams are known
simply as "titles", but the actual logical playback sequence is defined by one or more
"PGCs", or Program Group Chains, within the title. The PGC is in turn comprised of
multiple "PGs", or Programs", which are the actual video segments (and for a typical video
feature, sequentially ordered). The PGC structure, along with stream layout and metadata,
are stored in IFO files that need to be parsed. PGCs can be thought of as playlists in
easier terms.
An actual DVD player relies on user GUI interaction via menus and an internal VM to drive
the direction of demuxing. Generally, the user would either navigate (via menus) or
automatically be redirected to the PGC of their choice. During this process and the
subsequent playback, the DVD player's internal VM also maintains a state and executes
instructions that can create jumps to different sectors during playback. This is why
libdvdnav is involved, as a linear read of the MPEG-PS blobs on the disc (VOBs) is not
enough to produce the right sequence in many cases.
There are many other DVD structures (a long subject) that will not be discussed here. NAV
packets, in particular, are handled by this demuxer to build accurate timing but not
emitted as a stream. For a good high-level understanding, refer to:
<https://code.videolan.org/videolan/libdvdnav/-/blob/master/doc/dvd_structures>
Options
This demuxer accepts the following options:
title int
The title number to play. Must be set if pgc and pg are not set. Not applicable to
menus. Default is 0 (auto), which currently only selects the first available title
(title 1) and notifies the user about the implications.
chapter_start int
The chapter, or PTT (part-of-title), number to start at. Not applicable to menus.
Default is 1.
chapter_end int
The chapter, or PTT (part-of-title), number to end at. Not applicable to menus.
Default is 0, which is a special value to signal end at the last possible chapter.
angle int
The video angle number, referring to what is essentially an additional video stream
that is composed from alternate frames interleaved in the VOBs. Not applicable to
menus. Default is 1.
region int
The region code to use for playback. Some discs may use this to default playback at a
particular angle in different regions. This option will not affect the region code of
a real DVD drive, if used as an input. Not applicable to menus. Default is 0,
"world".
menu bool
Demux menu assets instead of navigating a title. Requires exact coordinates of the
menu (menu_lu, menu_vts, pgc, pg). Default is false.
menu_lu int
The menu language to demux. In DVD, menus are grouped by language. Default is 0, the
first language unit.
menu_vts int
The VTS where the menu lives, or 0 if it is a VMG menu (root-level). Default is 0,
VMG menu.
pgc int
The entry PGC to start playback, in conjunction with pg. Alternative to setting
title. Chapter markers are not supported at this time. Must be explicitly set for
menus. Default is 0, automatically resolve from value of title.
pg int
The entry PG to start playback, in conjunction with pgc. Alternative to setting
title. Chapter markers are not supported at this time. Default is 0, automatically
resolve from value of title, or start from the beginning (PG 1) of the menu.
preindex bool
Enable this to have accurate chapter (PTT) markers and duration measurement, which
requires a slow second pass read in order to index the chapter marker timestamps from
NAV packets. This is non-ideal extra work for real optical drives. It is recommended
and faster to use this option with a backup of the DVD structure stored on a hard
drive. Not compatible with pgc and pg. Not applicable to menus. Default is 0, false.
trim bool
Skip padding cells (i.e. cells shorter than 1 second) from the beginning. There exist
many discs with filler segments at the beginning of the PGC, often with junk data
intended for controlling a real DVD player's buffering speed and with no other
material data value. Not applicable to menus. Default is 1, true.
Examples
• Open title 3 from a given DVD structure:
ffmpeg -f dvdvideo -title 3 -i <path to DVD> ...
• Open chapters 3-6 from title 1 from a given DVD structure:
ffmpeg -f dvdvideo -chapter_start 3 -chapter_end 6 -title 1 -i <path to DVD> ...
• Open only chapter 5 from title 1 from a given DVD structure:
ffmpeg -f dvdvideo -chapter_start 5 -chapter_end 5 -title 1 -i <path to DVD> ...
• Demux menu with language 1 from VTS 1, PGC 1, starting at PG 1:
ffmpeg -f dvdvideo -menu 1 -menu_lu 1 -menu_vts 1 -pgc 1 -pg 1 -i <path to DVD> ...
ea
Electronic Arts Multimedia format demuxer.
This format is used by various Electronic Arts games.
Options
merge_alpha bool
Normally the VP6 alpha channel (if exists) is returned as a secondary video stream, by
setting this option you can make the demuxer return a single video stream which
contains the alpha channel in addition to the ordinary video.
imf
Interoperable Master Format demuxer.
This demuxer presents audio and video streams found in an IMF Composition, as specified in
<https://doi.org/10.5594/SMPTE.ST2067-2.2020>.
ffmpeg [-assetmaps <path of ASSETMAP1>,<path of ASSETMAP2>,...] -i <path of CPL> ...
If "-assetmaps" is not specified, the demuxer looks for a file called ASSETMAP.xml in the
same directory as the CPL.
flv, live_flv, kux
Adobe Flash Video Format demuxer.
This demuxer is used to demux FLV files and RTMP network streams. In case of live network
streams, if you force format, you may use live_flv option instead of flv to survive
timestamp discontinuities. KUX is a flv variant used on the Youku platform.
ffmpeg -f flv -i myfile.flv ...
ffmpeg -f live_flv -i rtmp://<any.server>/anything/key ....
-flv_metadata bool
Allocate the streams according to the onMetaData array content.
-flv_ignore_prevtag bool
Ignore the size of previous tag value.
-flv_full_metadata bool
Output all context of the onMetadata.
gif
Animated GIF demuxer.
It accepts the following options:
min_delay
Set the minimum valid delay between frames in hundredths of seconds. Range is 0 to
6000. Default value is 2.
max_gif_delay
Set the maximum valid delay between frames in hundredth of seconds. Range is 0 to
65535. Default value is 65535 (nearly eleven minutes), the maximum value allowed by
the specification.
default_delay
Set the default delay between frames in hundredths of seconds. Range is 0 to 6000.
Default value is 10.
ignore_loop
GIF files can contain information to loop a certain number of times (or infinitely).
If ignore_loop is set to 1, then the loop setting from the input will be ignored and
looping will not occur. If set to 0, then looping will occur and will cycle the number
of times according to the GIF. Default value is 1.
For example, with the overlay filter, place an infinitely looping GIF over another video:
ffmpeg -i input.mp4 -ignore_loop 0 -i input.gif -filter_complex overlay=shortest=1 out.mkv
Note that in the above example the shortest option for overlay filter is used to end the
output video at the length of the shortest input file, which in this case is input.mp4 as
the GIF in this example loops infinitely.
hls
HLS demuxer
Apple HTTP Live Streaming demuxer.
This demuxer presents all AVStreams from all variant streams. The id field is set to the
bitrate variant index number. By setting the discard flags on AVStreams (by pressing 'a'
or 'v' in ffplay), the caller can decide which variant streams to actually receive. The
total bitrate of the variant that the stream belongs to is available in a metadata key
named "variant_bitrate".
It accepts the following options:
live_start_index
segment index to start live streams at (negative values are from the end).
prefer_x_start
prefer to use #EXT-X-START if it's in playlist instead of live_start_index.
allowed_extensions
',' separated list of file extensions that hls is allowed to access.
max_reload
Maximum number of times a insufficient list is attempted to be reloaded. Default
value is 1000.
m3u8_hold_counters
The maximum number of times to load m3u8 when it refreshes without new segments.
Default value is 1000.
http_persistent
Use persistent HTTP connections. Applicable only for HTTP streams. Enabled by
default.
http_multiple
Use multiple HTTP connections for downloading HTTP segments. Enabled by default for
HTTP/1.1 servers.
http_seekable
Use HTTP partial requests for downloading HTTP segments. 0 = disable, 1 = enable, -1
= auto, Default is auto.
seg_format_options
Set options for the demuxer of media segments using a list of key=value pairs
separated by ":".
seg_max_retry
Maximum number of times to reload a segment on error, useful when segment skip on
network error is not desired. Default value is 0.
image2
Image file demuxer.
This demuxer reads from a list of image files specified by a pattern. The syntax and
meaning of the pattern is specified by the option pattern_type.
The pattern may contain a suffix which is used to automatically determine the format of
the images contained in the files.
The size, the pixel format, and the format of each image must be the same for all the
files in the sequence.
This demuxer accepts the following options:
framerate
Set the frame rate for the video stream. It defaults to 25.
loop
If set to 1, loop over the input. Default value is 0.
pattern_type
Select the pattern type used to interpret the provided filename.
pattern_type accepts one of the following values.
none
Disable pattern matching, therefore the video will only contain the specified
image. You should use this option if you do not want to create sequences from
multiple images and your filenames may contain special pattern characters.
sequence
Select a sequence pattern type, used to specify a sequence of files indexed by
sequential numbers.
A sequence pattern may contain the string "%d" or "%0Nd", which specifies the
position of the characters representing a sequential number in each filename
matched by the pattern. If the form "%d0Nd" is used, the string representing the
number in each filename is 0-padded and N is the total number of 0-padded digits
representing the number. The literal character '%' can be specified in the pattern
with the string "%%".
If the sequence pattern contains "%d" or "%0Nd", the first filename of the file
list specified by the pattern must contain a number inclusively contained between
start_number and start_number+start_number_range-1, and all the following numbers
must be sequential.
For example the pattern "img-%03d.bmp" will match a sequence of filenames of the
form img-001.bmp, img-002.bmp, ..., img-010.bmp, etc.; the pattern
"i%%m%%g-%d.jpg" will match a sequence of filenames of the form i%m%g-1.jpg,
i%m%g-2.jpg, ..., i%m%g-10.jpg, etc.
Note that the pattern must not necessarily contain "%d" or "%0Nd", for example to
convert a single image file img.jpeg you can employ the command:
ffmpeg -i img.jpeg img.png
glob
Select a glob wildcard pattern type.
The pattern is interpreted like a glob() pattern. This is only selectable if
libavformat was compiled with globbing support.
glob_sequence (deprecated, will be removed)
Select a mixed glob wildcard/sequence pattern.
If your version of libavformat was compiled with globbing support, and the
provided pattern contains at least one glob meta character among "%*?[]{}" that is
preceded by an unescaped "%", the pattern is interpreted like a glob() pattern,
otherwise it is interpreted like a sequence pattern.
All glob special characters "%*?[]{}" must be prefixed with "%". To escape a
literal "%" you shall use "%%".
For example the pattern "foo-%*.jpeg" will match all the filenames prefixed by
"foo-" and terminating with ".jpeg", and "foo-%?%?%?.jpeg" will match all the
filenames prefixed with "foo-", followed by a sequence of three characters, and
terminating with ".jpeg".
This pattern type is deprecated in favor of glob and sequence.
Default value is glob_sequence.
pixel_format
Set the pixel format of the images to read. If not specified the pixel format is
guessed from the first image file in the sequence.
start_number
Set the index of the file matched by the image file pattern to start to read from.
Default value is 0.
start_number_range
Set the index interval range to check when looking for the first image file in the
sequence, starting from start_number. Default value is 5.
ts_from_file
If set to 1, will set frame timestamp to modification time of image file. Note that
monotonity of timestamps is not provided: images go in the same order as without this
option. Default value is 0. If set to 2, will set frame timestamp to the modification
time of the image file in nanosecond precision.
video_size
Set the video size of the images to read. If not specified the video size is guessed
from the first image file in the sequence.
export_path_metadata
If set to 1, will add two extra fields to the metadata found in input, making them
also available for other filters (see drawtext filter for examples). Default value is
0. The extra fields are described below:
lavf.image2dec.source_path
Corresponds to the full path to the input file being read.
lavf.image2dec.source_basename
Corresponds to the name of the file being read.
Examples
• Use ffmpeg for creating a video from the images in the file sequence img-001.jpeg,
img-002.jpeg, ..., assuming an input frame rate of 10 frames per second:
ffmpeg -framerate 10 -i 'img-%03d.jpeg' out.mkv
• As above, but start by reading from a file with index 100 in the sequence:
ffmpeg -framerate 10 -start_number 100 -i 'img-%03d.jpeg' out.mkv
• Read images matching the "*.png" glob pattern , that is all the files terminating with
the ".png" suffix:
ffmpeg -framerate 10 -pattern_type glob -i "*.png" out.mkv
libgme
The Game Music Emu library is a collection of video game music file emulators.
See <https://bitbucket.org/mpyne/game-music-emu/overview> for more information.
It accepts the following options:
track_index
Set the index of which track to demux. The demuxer can only export one track. Track
indexes start at 0. Default is to pick the first track. Number of tracks is exported
as tracks metadata entry.
sample_rate
Set the sampling rate of the exported track. Range is 1000 to 999999. Default is
44100.
max_size (bytes)
The demuxer buffers the entire file into memory. Adjust this value to set the maximum
buffer size, which in turn, acts as a ceiling for the size of files that can be read.
Default is 50 MiB.
libmodplug
ModPlug based module demuxer
See <https://github.com/Konstanty/libmodplug>
It will export one 2-channel 16-bit 44.1 kHz audio stream. Optionally, a "pal8" 16-color
video stream can be exported with or without printed metadata.
It accepts the following options:
noise_reduction
Apply a simple low-pass filter. Can be 1 (on) or 0 (off). Default is 0.
reverb_depth
Set amount of reverb. Range 0-100. Default is 0.
reverb_delay
Set delay in ms, clamped to 40-250 ms. Default is 0.
bass_amount
Apply bass expansion a.k.a. XBass or megabass. Range is 0 (quiet) to 100 (loud).
Default is 0.
bass_range
Set cutoff i.e. upper-bound for bass frequencies. Range is 10-100 Hz. Default is 0.
surround_depth
Apply a Dolby Pro-Logic surround effect. Range is 0 (quiet) to 100 (heavy). Default is
0.
surround_delay
Set surround delay in ms, clamped to 5-40 ms. Default is 0.
max_size
The demuxer buffers the entire file into memory. Adjust this value to set the maximum
buffer size, which in turn, acts as a ceiling for the size of files that can be read.
Range is 0 to 100 MiB. 0 removes buffer size limit (not recommended). Default is 5
MiB.
video_stream_expr
String which is evaluated using the eval API to assign colors to the generated video
stream. Variables which can be used are "x", "y", "w", "h", "t", "speed", "tempo",
"order", "pattern" and "row".
video_stream
Generate video stream. Can be 1 (on) or 0 (off). Default is 0.
video_stream_w
Set video frame width in 'chars' where one char indicates 8 pixels. Range is 20-512.
Default is 30.
video_stream_h
Set video frame height in 'chars' where one char indicates 8 pixels. Range is 20-512.
Default is 30.
video_stream_ptxt
Print metadata on video stream. Includes "speed", "tempo", "order", "pattern", "row"
and "ts" (time in ms). Can be 1 (on) or 0 (off). Default is 1.
libopenmpt
libopenmpt based module demuxer
See <https://lib.openmpt.org/libopenmpt/> for more information.
Some files have multiple subsongs (tracks) this can be set with the subsong option.
It accepts the following options:
subsong
Set the subsong index. This can be either 'all', 'auto', or the index of the subsong.
Subsong indexes start at 0. The default is 'auto'.
The default value is to let libopenmpt choose.
layout
Set the channel layout. Valid values are 1, 2, and 4 channel layouts. The default
value is STEREO.
sample_rate
Set the sample rate for libopenmpt to output. Range is from 1000 to INT_MAX. The
value default is 48000.
mov/mp4/3gp
Demuxer for Quicktime File Format & ISO/IEC Base Media File Format (ISO/IEC 14496-12 or
MPEG-4 Part 12, ISO/IEC 15444-12 or JPEG 2000 Part 12).
Registered extensions: mov, mp4, m4a, 3gp, 3g2, mj2, psp, m4b, ism, ismv, isma, f4v
Options
This demuxer accepts the following options:
enable_drefs
Enable loading of external tracks, disabled by default. Enabling this can
theoretically leak information in some use cases.
use_absolute_path
Allows loading of external tracks via absolute paths, disabled by default. Enabling
this poses a security risk. It should only be enabled if the source is known to be
non-malicious.
seek_streams_individually
When seeking, identify the closest point in each stream individually and demux packets
in that stream from identified point. This can lead to a different sequence of packets
compared to demuxing linearly from the beginning. Default is true.
ignore_editlist
Ignore any edit list atoms. The demuxer, by default, modifies the stream index to
reflect the timeline described by the edit list. Default is false.
advanced_editlist
Modify the stream index to reflect the timeline described by the edit list.
"ignore_editlist" must be set to false for this option to be effective. If both
"ignore_editlist" and this option are set to false, then only the start of the stream
index is modified to reflect initial dwell time or starting timestamp described by the
edit list. Default is true.
ignore_chapters
Don't parse chapters. This includes GoPro 'HiLight' tags/moments. Note that chapters
are only parsed when input is seekable. Default is false.
use_mfra_for
For seekable fragmented input, set fragment's starting timestamp from media fragment
random access box, if present.
Following options are available:
auto
Auto-detect whether to set mfra timestamps as PTS or DTS (default)
dts Set mfra timestamps as DTS
pts Set mfra timestamps as PTS
0 Don't use mfra box to set timestamps
use_tfdt
For fragmented input, set fragment's starting timestamp to "baseMediaDecodeTime" from
the "tfdt" box. Default is enabled, which will prefer to use the "tfdt" box to set
DTS. Disable to use the "earliest_presentation_time" from the "sidx" box. In either
case, the timestamp from the "mfra" box will be used if it's available and
"use_mfra_for" is set to pts or dts.
export_all
Export unrecognized boxes within the udta box as metadata entries. The first four
characters of the box type are set as the key. Default is false.
export_xmp
Export entire contents of XMP_ box and uuid box as a string with key "xmp". Note that
if "export_all" is set and this option isn't, the contents of XMP_ box are still
exported but with key "XMP_". Default is false.
activation_bytes
4-byte key required to decrypt Audible AAX and AAX+ files. See Audible AAX subsection
below.
audible_fixed_key
Fixed key used for handling Audible AAX/AAX+ files. It has been pre-set so should not
be necessary to specify.
decryption_key
16-byte key, in hex, to decrypt files encrypted using ISO Common Encryption
(CENC/AES-128 CTR; ISO/IEC 23001-7).
max_stts_delta
Very high sample deltas written in a trak's stts box may occasionally be intended but
usually they are written in error or used to store a negative value for dts correction
when treated as signed 32-bit integers. This option lets the user set an upper limit,
beyond which the delta is clamped to 1. Values greater than the limit if negative when
cast to int32 are used to adjust onward dts.
Unit is the track time scale. Range is 0 to UINT_MAX. Default is "UINT_MAX - 48000*10"
which allows up to a 10 second dts correction for 48 kHz audio streams while
accommodating 99.9% of "uint32" range.
interleaved_read
Interleave packets from multiple tracks at demuxer level. For badly interleaved files,
this prevents playback issues caused by large gaps between packets in different
tracks, as MOV/MP4 do not have packet placement requirements. However, this can cause
excessive seeking on very badly interleaved files, due to seeking between tracks, so
disabling it may prevent I/O issues, at the expense of playback.
Audible AAX
Audible AAX files are encrypted M4B files, and they can be decrypted by specifying a 4
byte activation secret.
ffmpeg -activation_bytes 1CEB00DA -i test.aax -vn -c:a copy output.mp4
mpegts
MPEG-2 transport stream demuxer.
This demuxer accepts the following options:
resync_size
Set size limit for looking up a new synchronization. Default value is 65536.
skip_unknown_pmt
Skip PMTs for programs not defined in the PAT. Default value is 0.
fix_teletext_pts
Override teletext packet PTS and DTS values with the timestamps calculated from the
PCR of the first program which the teletext stream is part of and is not discarded.
Default value is 1, set this option to 0 if you want your teletext packet PTS and DTS
values untouched.
ts_packetsize
Output option carrying the raw packet size in bytes. Show the detected raw packet
size, cannot be set by the user.
scan_all_pmts
Scan and combine all PMTs. The value is an integer with value from -1 to 1 (-1 means
automatic setting, 1 means enabled, 0 means disabled). Default value is -1.
merge_pmt_versions
Re-use existing streams when a PMT's version is updated and elementary streams move to
different PIDs. Default value is 0.
max_packet_size
Set maximum size, in bytes, of packet emitted by the demuxer. Payloads above this size
are split across multiple packets. Range is 1 to INT_MAX/2. Default is 204800 bytes.
mpjpeg
MJPEG encapsulated in multi-part MIME demuxer.
This demuxer allows reading of MJPEG, where each frame is represented as a part of
multipart/x-mixed-replace stream.
strict_mime_boundary
Default implementation applies a relaxed standard to multi-part MIME boundary
detection, to prevent regression with numerous existing endpoints not generating a
proper MIME MJPEG stream. Turning this option on by setting it to 1 will result in a
stricter check of the boundary value.
rawvideo
Raw video demuxer.
This demuxer allows one to read raw video data. Since there is no header specifying the
assumed video parameters, the user must specify them in order to be able to decode the
data correctly.
This demuxer accepts the following options:
framerate
Set input video frame rate. Default value is 25.
pixel_format
Set the input video pixel format. Default value is "yuv420p".
video_size
Set the input video size. This value must be specified explicitly.
For example to read a rawvideo file input.raw with ffplay, assuming a pixel format of
"rgb24", a video size of "320x240", and a frame rate of 10 images per second, use the
command:
ffplay -f rawvideo -pixel_format rgb24 -video_size 320x240 -framerate 10 input.raw
rcwt
RCWT (Raw Captions With Time) is a format native to ccextractor, a commonly used open
source tool for processing 608/708 Closed Captions (CC) sources. For more information on
the format, see .
This demuxer implements the specification as of March 2024, which has been stable and
unchanged since April 2014.
Examples
• Render CC to ASS using the built-in decoder:
ffmpeg -i CC.rcwt.bin CC.ass
Note that if your output appears to be empty, you may have to manually set the
decoder's data_field option to pick the desired CC substream.
• Convert an RCWT backup to Scenarist (SCC) format:
ffmpeg -i CC.rcwt.bin -c:s copy CC.scc
Note that the SCC format does not support all of the possible CC extensions that can
be stored in RCWT (such as EIA-708).
sbg
SBaGen script demuxer.
This demuxer reads the script language used by SBaGen <http://uazu.net/sbagen/> to
generate binaural beats sessions. A SBG script looks like that:
-SE
a: 300-2.5/3 440+4.5/0
b: 300-2.5/0 440+4.5/3
off: -
NOW == a
+0:07:00 == b
+0:14:00 == a
+0:21:00 == b
+0:30:00 off
A SBG script can mix absolute and relative timestamps. If the script uses either only
absolute timestamps (including the script start time) or only relative ones, then its
layout is fixed, and the conversion is straightforward. On the other hand, if the script
mixes both kind of timestamps, then the NOW reference for relative timestamps will be
taken from the current time of day at the time the script is read, and the script layout
will be frozen according to that reference. That means that if the script is directly
played, the actual times will match the absolute timestamps up to the sound controller's
clock accuracy, but if the user somehow pauses the playback or seeks, all times will be
shifted accordingly.
tedcaptions
JSON captions used for <http://www.ted.com/>.
TED does not provide links to the captions, but they can be guessed from the page. The
file tools/bookmarklets.html from the FFmpeg source tree contains a bookmarklet to expose
them.
This demuxer accepts the following option:
start_time
Set the start time of the TED talk, in milliseconds. The default is 15000 (15s). It is
used to sync the captions with the downloadable videos, because they include a 15s
intro.
Example: convert the captions to a format most players understand:
ffmpeg -i http://www.ted.com/talks/subtitles/id/1/lang/en talk1-en.srt
vapoursynth
Vapoursynth wrapper.
Due to security concerns, Vapoursynth scripts will not be autodetected so the input format
has to be forced. For ff* CLI tools, add "-f vapoursynth" before the input "-i
yourscript.vpy".
This demuxer accepts the following option:
max_script_size
The demuxer buffers the entire script into memory. Adjust this value to set the
maximum buffer size, which in turn, acts as a ceiling for the size of scripts that can
be read. Default is 1 MiB.
w64
Sony Wave64 Audio demuxer.
This demuxer accepts the following options:
max_size
See the same option for the wav demuxer.
wav
RIFF Wave Audio demuxer.
This demuxer accepts the following options:
max_size
Specify the maximum packet size in bytes for the demuxed packets. By default this is
set to 0, which means that a sensible value is chosen based on the input format.
METADATA
FFmpeg is able to dump metadata from media files into a simple UTF-8-encoded INI-like text
file and then load it back using the metadata muxer/demuxer.
The file format is as follows:
1. A file consists of a header and a number of metadata tags divided into sections, each
on its own line.
2. The header is a ;FFMETADATA string, followed by a version number (now 1).
3. Metadata tags are of the form key=value
4. Immediately after header follows global metadata
5. After global metadata there may be sections with per-stream/per-chapter metadata.
6. A section starts with the section name in uppercase (i.e. STREAM or CHAPTER) in
brackets ([, ]) and ends with next section or end of file.
7. At the beginning of a chapter section there may be an optional timebase to be used for
start/end values. It must be in form TIMEBASE=num/den, where num and den are integers.
If the timebase is missing then start/end times are assumed to be in nanoseconds.
Next a chapter section must contain chapter start and end times in form START=num,
END=num, where num is a positive integer.
8. Empty lines and lines starting with ; or # are ignored.
9. Metadata keys or values containing special characters (=, ;, #, \ and a newline) must
be escaped with a backslash \.
10. Note that whitespace in metadata (e.g. foo = bar) is considered to be a part of the
tag (in the example above key is foo , value is
bar).
A ffmetadata file might look like this:
;FFMETADATA1
title=bike\\shed
;this is a comment
artist=FFmpeg troll team
[CHAPTER]
TIMEBASE=1/1000
START=0
#chapter ends at 0:01:00
END=60000
title=chapter \#1
[STREAM]
title=multi\
line
By using the ffmetadata muxer and demuxer it is possible to extract metadata from an input
file to an ffmetadata file, and then transcode the file into an output file with the
edited ffmetadata file.
Extracting an ffmetadata file with ffmpeg goes as follows:
ffmpeg -i INPUT -f ffmetadata FFMETADATAFILE
Reinserting edited metadata information from the FFMETADATAFILE file can be done as:
ffmpeg -i INPUT -i FFMETADATAFILE -map_metadata 1 -codec copy OUTPUT
PROTOCOL OPTIONS
The libavformat library provides some generic global options, which can be set on all the
protocols. In addition each protocol may support so-called private options, which are
specific for that component.
Options may be set by specifying -option value in the FFmpeg tools, or by setting the
value explicitly in the "AVFormatContext" options or using the libavutil/opt.h API for
programmatic use.
The list of supported options follows:
protocol_whitelist list (input)
Set a ","-separated list of allowed protocols. "ALL" matches all protocols. Protocols
prefixed by "-" are disabled. All protocols are allowed by default but protocols used
by an another protocol (nested protocols) are restricted to a per protocol subset.
PROTOCOLS
Protocols are configured elements in FFmpeg that enable access to resources that require
specific protocols.
When you configure your FFmpeg build, all the supported protocols are enabled by default.
You can list all available ones using the configure option "--list-protocols".
You can disable all the protocols using the configure option "--disable-protocols", and
selectively enable a protocol using the option "--enable-protocol=PROTOCOL", or you can
disable a particular protocol using the option "--disable-protocol=PROTOCOL".
The option "-protocols" of the ff* tools will display the list of supported protocols.
All protocols accept the following options:
rw_timeout
Maximum time to wait for (network) read/write operations to complete, in microseconds.
A description of the currently available protocols follows.
amqp
Advanced Message Queueing Protocol (AMQP) version 0-9-1 is a broker based publish-
subscribe communication protocol.
FFmpeg must be compiled with --enable-librabbitmq to support AMQP. A separate AMQP broker
must also be run. An example open-source AMQP broker is RabbitMQ.
After starting the broker, an FFmpeg client may stream data to the broker using the
command:
ffmpeg -re -i input -f mpegts amqp://[[user]:[password]@]hostname[:port][/vhost]
Where hostname and port (default is 5672) is the address of the broker. The client may
also set a user/password for authentication. The default for both fields is "guest". Name
of virtual host on broker can be set with vhost. The default value is "/".
Muliple subscribers may stream from the broker using the command:
ffplay amqp://[[user]:[password]@]hostname[:port][/vhost]
In RabbitMQ all data published to the broker flows through a specific exchange, and each
subscribing client has an assigned queue/buffer. When a packet arrives at an exchange, it
may be copied to a client's queue depending on the exchange and routing_key fields.
The following options are supported:
exchange
Sets the exchange to use on the broker. RabbitMQ has several predefined exchanges:
"amq.direct" is the default exchange, where the publisher and subscriber must have a
matching routing_key; "amq.fanout" is the same as a broadcast operation (i.e. the data
is forwarded to all queues on the fanout exchange independent of the routing_key); and
"amq.topic" is similar to "amq.direct", but allows for more complex pattern matching
(refer to the RabbitMQ documentation).
routing_key
Sets the routing key. The default value is "amqp". The routing key is used on the
"amq.direct" and "amq.topic" exchanges to decide whether packets are written to the
queue of a subscriber.
pkt_size
Maximum size of each packet sent/received to the broker. Default is 131072. Minimum
is 4096 and max is any large value (representable by an int). When receiving packets,
this sets an internal buffer size in FFmpeg. It should be equal to or greater than the
size of the published packets to the broker. Otherwise the received message may be
truncated causing decoding errors.
connection_timeout
The timeout in seconds during the initial connection to the broker. The default value
is rw_timeout, or 5 seconds if rw_timeout is not set.
delivery_mode mode
Sets the delivery mode of each message sent to broker. The following values are
accepted:
persistent
Delivery mode set to "persistent" (2). This is the default value. Messages may be
written to the broker's disk depending on its setup.
non-persistent
Delivery mode set to "non-persistent" (1). Messages will stay in broker's memory
unless the broker is under memory pressure.
async
Asynchronous data filling wrapper for input stream.
Fill data in a background thread, to decouple I/O operation from demux thread.
async:<URL>
async:http://host/resource
async:cache:http://host/resource
bluray
Read BluRay playlist.
The accepted options are:
angle
BluRay angle
chapter
Start chapter (1...N)
playlist
Playlist to read (BDMV/PLAYLIST/?????.mpls)
Examples:
Read longest playlist from BluRay mounted to /mnt/bluray:
bluray:/mnt/bluray
Read angle 2 of playlist 4 from BluRay mounted to /mnt/bluray, start from chapter 2:
-playlist 4 -angle 2 -chapter 2 bluray:/mnt/bluray
cache
Caching wrapper for input stream.
Cache the input stream to temporary file. It brings seeking capability to live streams.
The accepted options are:
read_ahead_limit
Amount in bytes that may be read ahead when seeking isn't supported. Range is -1 to
INT_MAX. -1 for unlimited. Default is 65536.
URL Syntax is
cache:<URL>
concat
Physical concatenation protocol.
Read and seek from many resources in sequence as if they were a unique resource.
A URL accepted by this protocol has the syntax:
concat:<URL1>|<URL2>|...|<URLN>
where URL1, URL2, ..., URLN are the urls of the resource to be concatenated, each one
possibly specifying a distinct protocol.
For example to read a sequence of files split1.mpeg, split2.mpeg, split3.mpeg with ffplay
use the command:
ffplay concat:split1.mpeg\|split2.mpeg\|split3.mpeg
Note that you may need to escape the character "|" which is special for many shells.
concatf
Physical concatenation protocol using a line break delimited list of resources.
Read and seek from many resources in sequence as if they were a unique resource.
A URL accepted by this protocol has the syntax:
concatf:<URL>
where URL is the url containing a line break delimited list of resources to be
concatenated, each one possibly specifying a distinct protocol. Special characters must be
escaped with backslash or single quotes. See the "Quoting and escaping" section in the
ffmpeg-utils(1) manual.
For example to read a sequence of files split1.mpeg, split2.mpeg, split3.mpeg listed in
separate lines within a file split.txt with ffplay use the command:
ffplay concatf:split.txt
Where split.txt contains the lines:
split1.mpeg
split2.mpeg
split3.mpeg
crypto
AES-encrypted stream reading protocol.
The accepted options are:
key Set the AES decryption key binary block from given hexadecimal representation.
iv Set the AES decryption initialization vector binary block from given hexadecimal
representation.
Accepted URL formats:
crypto:<URL>
crypto+<URL>
data
Data in-line in the URI. See <http://en.wikipedia.org/wiki/Data_URI_scheme>.
For example, to convert a GIF file given inline with ffmpeg:
ffmpeg -i "data:image/gif;base64,R0lGODdhCAAIAMIEAAAAAAAA//8AAP//AP///////////////ywAAAAACAAIAAADF0gEDLojDgdGiJdJqUX02iB4E8Q9jUMkADs=" smiley.png
fd
File descriptor access protocol.
The accepted syntax is:
fd: -fd <file_descriptor>
If fd is not specified, by default the stdout file descriptor will be used for writing,
stdin for reading. Unlike the pipe protocol, fd protocol has seek support if it
corresponding to a regular file. fd protocol doesn't support pass file descriptor via URL
for security.
This protocol accepts the following options:
blocksize
Set I/O operation maximum block size, in bytes. Default value is "INT_MAX", which
results in not limiting the requested block size. Setting this value reasonably low
improves user termination request reaction time, which is valuable if data
transmission is slow.
fd Set file descriptor.
file
File access protocol.
Read from or write to a file.
A file URL can have the form:
file:<filename>
where filename is the path of the file to read.
An URL that does not have a protocol prefix will be assumed to be a file URL. Depending on
the build, an URL that looks like a Windows path with the drive letter at the beginning
will also be assumed to be a file URL (usually not the case in builds for unix-like
systems).
For example to read from a file input.mpeg with ffmpeg use the command:
ffmpeg -i file:input.mpeg output.mpeg
This protocol accepts the following options:
truncate
Truncate existing files on write, if set to 1. A value of 0 prevents truncating.
Default value is 1.
blocksize
Set I/O operation maximum block size, in bytes. Default value is "INT_MAX", which
results in not limiting the requested block size. Setting this value reasonably low
improves user termination request reaction time, which is valuable for files on slow
medium.
follow
If set to 1, the protocol will retry reading at the end of the file, allowing reading
files that still are being written. In order for this to terminate, you either need to
use the rw_timeout option, or use the interrupt callback (for API users).
seekable
Controls if seekability is advertised on the file. 0 means non-seekable, -1 means auto
(seekable for normal files, non-seekable for named pipes).
Many demuxers handle seekable and non-seekable resources differently, overriding this
might speed up opening certain files at the cost of losing some features (e.g.
accurate seeking).
ftp
FTP (File Transfer Protocol).
Read from or write to remote resources using FTP protocol.
Following syntax is required.
ftp://[user[:password]@]server[:port]/path/to/remote/resource.mpeg
This protocol accepts the following options.
timeout
Set timeout in microseconds of socket I/O operations used by the underlying low level
operation. By default it is set to -1, which means that the timeout is not specified.
ftp-user
Set a user to be used for authenticating to the FTP server. This is overridden by the
user in the FTP URL.
ftp-password
Set a password to be used for authenticating to the FTP server. This is overridden by
the password in the FTP URL, or by ftp-anonymous-password if no user is set.
ftp-anonymous-password
Password used when login as anonymous user. Typically an e-mail address should be
used.
ftp-write-seekable
Control seekability of connection during encoding. If set to 1 the resource is
supposed to be seekable, if set to 0 it is assumed not to be seekable. Default value
is 0.
NOTE: Protocol can be used as output, but it is recommended to not do it, unless special
care is taken (tests, customized server configuration etc.). Different FTP servers behave
in different way during seek operation. ff* tools may produce incomplete content due to
server limitations.
gopher
Gopher protocol.
gophers
Gophers protocol.
The Gopher protocol with TLS encapsulation.
hls
Read Apple HTTP Live Streaming compliant segmented stream as a uniform one. The M3U8
playlists describing the segments can be remote HTTP resources or local files, accessed
using the standard file protocol. The nested protocol is declared by specifying "+proto"
after the hls URI scheme name, where proto is either "file" or "http".
hls+http://host/path/to/remote/resource.m3u8
hls+file://path/to/local/resource.m3u8
Using this protocol is discouraged - the hls demuxer should work just as well (if not,
please report the issues) and is more complete. To use the hls demuxer instead, simply
use the direct URLs to the m3u8 files.
http
HTTP (Hyper Text Transfer Protocol).
This protocol accepts the following options:
seekable
Control seekability of connection. If set to 1 the resource is supposed to be
seekable, if set to 0 it is assumed not to be seekable, if set to -1 it will try to
autodetect if it is seekable. Default value is -1.
chunked_post
If set to 1 use chunked Transfer-Encoding for posts, default is 1.
http_proxy
set HTTP proxy to tunnel through e.g. http://example.com:1234
headers
Set custom HTTP headers, can override built in default headers. The value must be a
string encoding the headers.
content_type
Set a specific content type for the POST messages or for listen mode.
user_agent
Override the User-Agent header. If not specified the protocol will use a string
describing the libavformat build. ("Lavf/<version>")
referer
Set the Referer header. Include 'Referer: URL' header in HTTP request.
multiple_requests
Use persistent connections if set to 1, default is 0.
post_data
Set custom HTTP post data.
mime_type
Export the MIME type.
http_version
Exports the HTTP response version number. Usually "1.0" or "1.1".
cookies
Set the cookies to be sent in future requests. The format of each cookie is the same
as the value of a Set-Cookie HTTP response field. Multiple cookies can be delimited by
a newline character.
icy If set to 1 request ICY (SHOUTcast) metadata from the server. If the server supports
this, the metadata has to be retrieved by the application by reading the
icy_metadata_headers and icy_metadata_packet options. The default is 1.
icy_metadata_headers
If the server supports ICY metadata, this contains the ICY-specific HTTP reply
headers, separated by newline characters.
icy_metadata_packet
If the server supports ICY metadata, and icy was set to 1, this contains the last non-
empty metadata packet sent by the server. It should be polled in regular intervals by
applications interested in mid-stream metadata updates.
metadata
Set an exported dictionary containing Icecast metadata from the bitstream, if present.
Only useful with the C API.
auth_type
Set HTTP authentication type. No option for Digest, since this method requires getting
nonce parameters from the server first and can't be used straight away like Basic.
none
Choose the HTTP authentication type automatically. This is the default.
basic
Choose the HTTP basic authentication.
Basic authentication sends a Base64-encoded string that contains a user name and
password for the client. Base64 is not a form of encryption and should be
considered the same as sending the user name and password in clear text (Base64 is
a reversible encoding). If a resource needs to be protected, strongly consider
using an authentication scheme other than basic authentication. HTTPS/TLS should
be used with basic authentication. Without these additional security
enhancements, basic authentication should not be used to protect sensitive or
valuable information.
send_expect_100
Send an Expect: 100-continue header for POST. If set to 1 it will send, if set to 0 it
won't, if set to -1 it will try to send if it is applicable. Default value is -1.
location
An exported dictionary containing the content location. Only useful with the C API.
offset
Set initial byte offset.
end_offset
Try to limit the request to bytes preceding this offset.
method
When used as a client option it sets the HTTP method for the request.
When used as a server option it sets the HTTP method that is going to be expected from
the client(s). If the expected and the received HTTP method do not match the client
will be given a Bad Request response. When unset the HTTP method is not checked for
now. This will be replaced by autodetection in the future.
reconnect
Reconnect automatically when disconnected before EOF is hit.
reconnect_at_eof
If set then eof is treated like an error and causes reconnection, this is useful for
live / endless streams.
reconnect_on_network_error
Reconnect automatically in case of TCP/TLS errors during connect.
reconnect_on_http_error
A comma separated list of HTTP status codes to reconnect on. The list can include
specific status codes (e.g. '503') or the strings '4xx' / '5xx'.
reconnect_streamed
If set then even streamed/non seekable streams will be reconnected on errors.
reconnect_delay_max
Set the maximum delay in seconds after which to give up reconnecting.
reconnect_max_retries
Set the maximum number of times to retry a connection. Default unset.
reconnect_delay_total_max
Set the maximum total delay in seconds after which to give up reconnecting.
respect_retry_after
If enabled, and a Retry-After header is encountered, its requested reconnection delay
will be honored, rather than using exponential backoff. Useful for 429 and 503 errors.
Default enabled.
listen
If set to 1 enables experimental HTTP server. This can be used to send data when used
as an output option, or read data from a client with HTTP POST when used as an input
option. If set to 2 enables experimental multi-client HTTP server. This is not yet
implemented in ffmpeg.c and thus must not be used as a command line option.
# Server side (sending):
ffmpeg -i somefile.ogg -c copy -listen 1 -f ogg http://<server>:<port>
# Client side (receiving):
ffmpeg -i http://<server>:<port> -c copy somefile.ogg
# Client can also be done with wget:
wget http://<server>:<port> -O somefile.ogg
# Server side (receiving):
ffmpeg -listen 1 -i http://<server>:<port> -c copy somefile.ogg
# Client side (sending):
ffmpeg -i somefile.ogg -chunked_post 0 -c copy -f ogg http://<server>:<port>
# Client can also be done with wget:
wget --post-file=somefile.ogg http://<server>:<port>
resource
The resource requested by a client, when the experimental HTTP server is in use.
reply_code
The HTTP code returned to the client, when the experimental HTTP server is in use.
short_seek_size
Set the threshold, in bytes, for when a readahead should be prefered over a seek and
new HTTP request. This is useful, for example, to make sure the same connection is
used for reading large video packets with small audio packets in between.
HTTP Cookies
Some HTTP requests will be denied unless cookie values are passed in with the request. The
cookies option allows these cookies to be specified. At the very least, each cookie must
specify a value along with a path and domain. HTTP requests that match both the domain
and path will automatically include the cookie value in the HTTP Cookie header field.
Multiple cookies can be delimited by a newline.
The required syntax to play a stream specifying a cookie is:
ffplay -cookies "nlqptid=nltid=tsn; path=/; domain=somedomain.com;" http://somedomain.com/somestream.m3u8
Icecast
Icecast protocol (stream to Icecast servers)
This protocol accepts the following options:
ice_genre
Set the stream genre.
ice_name
Set the stream name.
ice_description
Set the stream description.
ice_url
Set the stream website URL.
ice_public
Set if the stream should be public. The default is 0 (not public).
user_agent
Override the User-Agent header. If not specified a string of the form "Lavf/<version>"
will be used.
password
Set the Icecast mountpoint password.
content_type
Set the stream content type. This must be set if it is different from audio/mpeg.
legacy_icecast
This enables support for Icecast versions < 2.4.0, that do not support the HTTP PUT
method but the SOURCE method.
tls Establish a TLS (HTTPS) connection to Icecast.
icecast://[<username>[:<password>]@]<server>:<port>/<mountpoint>
ipfs
InterPlanetary File System (IPFS) protocol support. One can access files stored on the
IPFS network through so-called gateways. These are http(s) endpoints. This protocol wraps
the IPFS native protocols (ipfs:// and ipns://) to be sent to such a gateway. Users can
(and should) host their own node which means this protocol will use one's local gateway to
access files on the IPFS network.
This protocol accepts the following options:
gateway
Defines the gateway to use. When not set, the protocol will first try locating the
local gateway by looking at $IPFS_GATEWAY, $IPFS_PATH and "$HOME/.ipfs/", in that
order.
One can use this protocol in 2 ways. Using IPFS:
ffplay ipfs://<hash>
Or the IPNS protocol (IPNS is mutable IPFS):
ffplay ipns://<hash>
mmst
MMS (Microsoft Media Server) protocol over TCP.
mmsh
MMS (Microsoft Media Server) protocol over HTTP.
The required syntax is:
mmsh://<server>[:<port>][/<app>][/<playpath>]
md5
MD5 output protocol.
Computes the MD5 hash of the data to be written, and on close writes this to the
designated output or stdout if none is specified. It can be used to test muxers without
writing an actual file.
Some examples follow.
# Write the MD5 hash of the encoded AVI file to the file output.avi.md5.
ffmpeg -i input.flv -f avi -y md5:output.avi.md5
# Write the MD5 hash of the encoded AVI file to stdout.
ffmpeg -i input.flv -f avi -y md5:
Note that some formats (typically MOV) require the output protocol to be seekable, so they
will fail with the MD5 output protocol.
pipe
UNIX pipe access protocol.
Read and write from UNIX pipes.
The accepted syntax is:
pipe:[<number>]
If fd isn't specified, number is the number corresponding to the file descriptor of the
pipe (e.g. 0 for stdin, 1 for stdout, 2 for stderr). If number is not specified, by
default the stdout file descriptor will be used for writing, stdin for reading.
For example to read from stdin with ffmpeg:
cat test.wav | ffmpeg -i pipe:0
# ...this is the same as...
cat test.wav | ffmpeg -i pipe:
For writing to stdout with ffmpeg:
ffmpeg -i test.wav -f avi pipe:1 | cat > test.avi
# ...this is the same as...
ffmpeg -i test.wav -f avi pipe: | cat > test.avi
This protocol accepts the following options:
blocksize
Set I/O operation maximum block size, in bytes. Default value is "INT_MAX", which
results in not limiting the requested block size. Setting this value reasonably low
improves user termination request reaction time, which is valuable if data
transmission is slow.
fd Set file descriptor.
Note that some formats (typically MOV), require the output protocol to be seekable, so
they will fail with the pipe output protocol.
prompeg
Pro-MPEG Code of Practice #3 Release 2 FEC protocol.
The Pro-MPEG CoP#3 FEC is a 2D parity-check forward error correction mechanism for MPEG-2
Transport Streams sent over RTP.
This protocol must be used in conjunction with the "rtp_mpegts" muxer and the "rtp"
protocol.
The required syntax is:
-f rtp_mpegts -fec prompeg=<option>=<val>... rtp://<hostname>:<port>
The destination UDP ports are "port + 2" for the column FEC stream and "port + 4" for the
row FEC stream.
This protocol accepts the following options:
l=n The number of columns (4-20, LxD <= 100)
d=n The number of rows (4-20, LxD <= 100)
Example usage:
-f rtp_mpegts -fec prompeg=l=8:d=4 rtp://<hostname>:<port>
rist
Reliable Internet Streaming Transport protocol
The accepted options are:
rist_profile
Supported values:
simple
main
This one is default.
advanced
buffer_size
Set internal RIST buffer size in milliseconds for retransmission of data. Default
value is 0 which means the librist default (1 sec). Maximum value is 30 seconds.
fifo_size
Size of the librist receiver output fifo in number of packets. This must be a power of
2. Defaults to 8192 (vs the librist default of 1024).
overrun_nonfatal=1|0
Survive in case of librist fifo buffer overrun. Default value is 0.
pkt_size
Set maximum packet size for sending data. 1316 by default.
log_level
Set loglevel for RIST logging messages. You only need to set this if you explicitly
want to enable debug level messages or packet loss simulation, otherwise the regular
loglevel is respected.
secret
Set override of encryption secret, by default is unset.
encryption
Set encryption type, by default is disabled. Acceptable values are 128 and 256.
rtmp
Real-Time Messaging Protocol.
The Real-Time Messaging Protocol (RTMP) is used for streaming multimedia content across a
TCP/IP network.
The required syntax is:
rtmp://[<username>:<password>@]<server>[:<port>][/<app>][/<instance>][/<playpath>]
The accepted parameters are:
username
An optional username (mostly for publishing).
password
An optional password (mostly for publishing).
server
The address of the RTMP server.
port
The number of the TCP port to use (by default is 1935).
app It is the name of the application to access. It usually corresponds to the path where
the application is installed on the RTMP server (e.g. /ondemand/, /flash/live/, etc.).
You can override the value parsed from the URI through the "rtmp_app" option, too.
playpath
It is the path or name of the resource to play with reference to the application
specified in app, may be prefixed by "mp4:". You can override the value parsed from
the URI through the "rtmp_playpath" option, too.
listen
Act as a server, listening for an incoming connection.
timeout
Maximum time to wait for the incoming connection. Implies listen.
Additionally, the following parameters can be set via command line options (or in code via
"AVOption"s):
rtmp_app
Name of application to connect on the RTMP server. This option overrides the parameter
specified in the URI.
rtmp_buffer
Set the client buffer time in milliseconds. The default is 3000.
rtmp_conn
Extra arbitrary AMF connection parameters, parsed from a string, e.g. like "B:1
S:authMe O:1 NN:code:1.23 NS:flag:ok O:0". Each value is prefixed by a single
character denoting the type, B for Boolean, N for number, S for string, O for object,
or Z for null, followed by a colon. For Booleans the data must be either 0 or 1 for
FALSE or TRUE, respectively. Likewise for Objects the data must be 0 or 1 to end or
begin an object, respectively. Data items in subobjects may be named, by prefixing the
type with 'N' and specifying the name before the value (i.e. "NB:myFlag:1"). This
option may be used multiple times to construct arbitrary AMF sequences.
rtmp_enhanced_codecs
Specify the list of codecs the client advertises to support in an enhanced RTMP
stream. This option should be set to a comma separated list of fourcc values, like
"hvc1,av01,vp09" for multiple codecs or "hvc1" for only one codec. The specified list
will be presented in the "fourCcLive" property of the Connect Command Message.
rtmp_flashver
Version of the Flash plugin used to run the SWF player. The default is LNX 9,0,124,2.
(When publishing, the default is FMLE/3.0 (compatible; <libavformat version>).)
rtmp_flush_interval
Number of packets flushed in the same request (RTMPT only). The default is 10.
rtmp_live
Specify that the media is a live stream. No resuming or seeking in live streams is
possible. The default value is "any", which means the subscriber first tries to play
the live stream specified in the playpath. If a live stream of that name is not found,
it plays the recorded stream. The other possible values are "live" and "recorded".
rtmp_pageurl
URL of the web page in which the media was embedded. By default no value will be sent.
rtmp_playpath
Stream identifier to play or to publish. This option overrides the parameter specified
in the URI.
rtmp_subscribe
Name of live stream to subscribe to. By default no value will be sent. It is only
sent if the option is specified or if rtmp_live is set to live.
rtmp_swfhash
SHA256 hash of the decompressed SWF file (32 bytes).
rtmp_swfsize
Size of the decompressed SWF file, required for SWFVerification.
rtmp_swfurl
URL of the SWF player for the media. By default no value will be sent.
rtmp_swfverify
URL to player swf file, compute hash/size automatically.
rtmp_tcurl
URL of the target stream. Defaults to proto://host[:port]/app.
tcp_nodelay=1|0
Set TCP_NODELAY to disable Nagle's algorithm. Default value is 0.
Remark: Writing to the socket is currently not optimized to minimize system calls and
reduces the efficiency / effect of TCP_NODELAY.
For example to read with ffplay a multimedia resource named "sample" from the application
"vod" from an RTMP server "myserver":
ffplay rtmp://myserver/vod/sample
To publish to a password protected server, passing the playpath and app names separately:
ffmpeg -re -i <input> -f flv -rtmp_playpath some/long/path -rtmp_app long/app/name rtmp://username:password@myserver/
rtmpe
Encrypted Real-Time Messaging Protocol.
The Encrypted Real-Time Messaging Protocol (RTMPE) is used for streaming multimedia
content within standard cryptographic primitives, consisting of Diffie-Hellman key
exchange and HMACSHA256, generating a pair of RC4 keys.
rtmps
Real-Time Messaging Protocol over a secure SSL connection.
The Real-Time Messaging Protocol (RTMPS) is used for streaming multimedia content across
an encrypted connection.
rtmpt
Real-Time Messaging Protocol tunneled through HTTP.
The Real-Time Messaging Protocol tunneled through HTTP (RTMPT) is used for streaming
multimedia content within HTTP requests to traverse firewalls.
rtmpte
Encrypted Real-Time Messaging Protocol tunneled through HTTP.
The Encrypted Real-Time Messaging Protocol tunneled through HTTP (RTMPTE) is used for
streaming multimedia content within HTTP requests to traverse firewalls.
rtmpts
Real-Time Messaging Protocol tunneled through HTTPS.
The Real-Time Messaging Protocol tunneled through HTTPS (RTMPTS) is used for streaming
multimedia content within HTTPS requests to traverse firewalls.
libsmbclient
libsmbclient permits one to manipulate CIFS/SMB network resources.
Following syntax is required.
smb://[[domain:]user[:password@]]server[/share[/path[/file]]]
This protocol accepts the following options.
timeout
Set timeout in milliseconds of socket I/O operations used by the underlying low level
operation. By default it is set to -1, which means that the timeout is not specified.
truncate
Truncate existing files on write, if set to 1. A value of 0 prevents truncating.
Default value is 1.
workgroup
Set the workgroup used for making connections. By default workgroup is not specified.
For more information see: <http://www.samba.org/>.
libssh
Secure File Transfer Protocol via libssh
Read from or write to remote resources using SFTP protocol.
Following syntax is required.
sftp://[user[:password]@]server[:port]/path/to/remote/resource.mpeg
This protocol accepts the following options.
timeout
Set timeout of socket I/O operations used by the underlying low level operation. By
default it is set to -1, which means that the timeout is not specified.
truncate
Truncate existing files on write, if set to 1. A value of 0 prevents truncating.
Default value is 1.
private_key
Specify the path of the file containing private key to use during authorization. By
default libssh searches for keys in the ~/.ssh/ directory.
Example: Play a file stored on remote server.
ffplay sftp://user:password@server_address:22/home/user/resource.mpeg
librtmp rtmp, rtmpe, rtmps, rtmpt, rtmpte
Real-Time Messaging Protocol and its variants supported through librtmp.
Requires the presence of the librtmp headers and library during configuration. You need to
explicitly configure the build with "--enable-librtmp". If enabled this will replace the
native RTMP protocol.
This protocol provides most client functions and a few server functions needed to support
RTMP, RTMP tunneled in HTTP (RTMPT), encrypted RTMP (RTMPE), RTMP over SSL/TLS (RTMPS) and
tunneled variants of these encrypted types (RTMPTE, RTMPTS).
The required syntax is:
<rtmp_proto>://<server>[:<port>][/<app>][/<playpath>] <options>
where rtmp_proto is one of the strings "rtmp", "rtmpt", "rtmpe", "rtmps", "rtmpte",
"rtmpts" corresponding to each RTMP variant, and server, port, app and playpath have the
same meaning as specified for the RTMP native protocol. options contains a list of space-
separated options of the form key=val.
See the librtmp manual page (man 3 librtmp) for more information.
For example, to stream a file in real-time to an RTMP server using ffmpeg:
ffmpeg -re -i myfile -f flv rtmp://myserver/live/mystream
To play the same stream using ffplay:
ffplay "rtmp://myserver/live/mystream live=1"
rtp
Real-time Transport Protocol.
The required syntax for an RTP URL is: rtp://hostname[:port][?option=val...]
port specifies the RTP port to use.
The following URL options are supported:
ttl=n
Set the TTL (Time-To-Live) value (for multicast only).
rtcpport=n
Set the remote RTCP port to n.
localrtpport=n
Set the local RTP port to n.
localrtcpport=n'
Set the local RTCP port to n.
pkt_size=n
Set max packet size (in bytes) to n.
buffer_size=size
Set the maximum UDP socket buffer size in bytes.
connect=0|1
Do a connect() on the UDP socket (if set to 1) or not (if set to 0).
sources=ip[,ip]
List allowed source IP addresses.
block=ip[,ip]
List disallowed (blocked) source IP addresses.
write_to_source=0|1
Send packets to the source address of the latest received packet (if set to 1) or to a
default remote address (if set to 0).
localport=n
Set the local RTP port to n.
localaddr=addr
Local IP address of a network interface used for sending packets or joining multicast
groups.
timeout=n
Set timeout (in microseconds) of socket I/O operations to n.
This is a deprecated option. Instead, localrtpport should be used.
Important notes:
1. If rtcpport is not set the RTCP port will be set to the RTP port value plus 1.
2. If localrtpport (the local RTP port) is not set any available port will be used for
the local RTP and RTCP ports.
3. If localrtcpport (the local RTCP port) is not set it will be set to the local RTP port
value plus 1.
rtsp
Real-Time Streaming Protocol.
RTSP is not technically a protocol handler in libavformat, it is a demuxer and muxer. The
demuxer supports both normal RTSP (with data transferred over RTP; this is used by e.g.
Apple and Microsoft) and Real-RTSP (with data transferred over RDT).
The muxer can be used to send a stream using RTSP ANNOUNCE to a server supporting it
(currently Darwin Streaming Server and Mischa Spiegelmock's
<https://github.com/revmischa/rtsp-server>).
The required syntax for a RTSP url is:
rtsp://<hostname>[:<port>]/<path>
Options can be set on the ffmpeg/ffplay command line, or set in code via "AVOption"s or in
"avformat_open_input".
Muxer
The following options are supported.
rtsp_transport
Set RTSP transport protocols.
It accepts the following values:
udp Use UDP as lower transport protocol.
tcp Use TCP (interleaving within the RTSP control channel) as lower transport
protocol.
Default value is 0.
rtsp_flags
Set RTSP flags.
The following values are accepted:
latm
Use MP4A-LATM packetization instead of MPEG4-GENERIC for AAC.
rfc2190
Use RFC 2190 packetization instead of RFC 4629 for H.263.
skip_rtcp
Don't send RTCP sender reports.
h264_mode0
Use mode 0 for H.264 in RTP.
send_bye
Send RTCP BYE packets when finishing.
Default value is 0.
min_port
Set minimum local UDP port. Default value is 5000.
max_port
Set maximum local UDP port. Default value is 65000.
buffer_size
Set the maximum socket buffer size in bytes.
pkt_size
Set max send packet size (in bytes). Default value is 1472.
Demuxer
The following options are supported.
initial_pause
Do not start playing the stream immediately if set to 1. Default value is 0.
rtsp_transport
Set RTSP transport protocols.
It accepts the following values:
udp Use UDP as lower transport protocol.
tcp Use TCP (interleaving within the RTSP control channel) as lower transport
protocol.
udp_multicast
Use UDP multicast as lower transport protocol.
http
Use HTTP tunneling as lower transport protocol, which is useful for passing
proxies.
https
Use HTTPs tunneling as lower transport protocol, which is useful for passing
proxies and widely used for security consideration.
Multiple lower transport protocols may be specified, in that case they are tried one
at a time (if the setup of one fails, the next one is tried). For the muxer, only the
tcp and udp options are supported.
rtsp_flags
Set RTSP flags.
The following values are accepted:
filter_src
Accept packets only from negotiated peer address and port.
listen
Act as a server, listening for an incoming connection.
prefer_tcp
Try TCP for RTP transport first, if TCP is available as RTSP RTP transport.
satip_raw
Export raw MPEG-TS stream instead of demuxing. The flag will simply write out the
raw stream, with the original PAT/PMT/PIDs intact.
Default value is none.
allowed_media_types
Set media types to accept from the server.
The following flags are accepted:
video
audio
data
subtitle
By default it accepts all media types.
min_port
Set minimum local UDP port. Default value is 5000.
max_port
Set maximum local UDP port. Default value is 65000.
listen_timeout
Set maximum timeout (in seconds) to establish an initial connection. Setting
listen_timeout > 0 sets rtsp_flags to listen. Default is -1 which means an infinite
timeout when listen mode is set.
reorder_queue_size
Set number of packets to buffer for handling of reordered packets.
timeout
Set socket TCP I/O timeout in microseconds.
user_agent
Override User-Agent header. If not specified, it defaults to the libavformat
identifier string.
buffer_size
Set the maximum socket buffer size in bytes.
When receiving data over UDP, the demuxer tries to reorder received packets (since they
may arrive out of order, or packets may get lost totally). This can be disabled by setting
the maximum demuxing delay to zero (via the "max_delay" field of AVFormatContext).
When watching multi-bitrate Real-RTSP streams with ffplay, the streams to display can be
chosen with "-vst" n and "-ast" n for video and audio respectively, and can be switched on
the fly by pressing "v" and "a".
Examples
The following examples all make use of the ffplay and ffmpeg tools.
• Watch a stream over UDP, with a max reordering delay of 0.5 seconds:
ffplay -max_delay 500000 -rtsp_transport udp rtsp://server/video.mp4
• Watch a stream tunneled over HTTP:
ffplay -rtsp_transport http rtsp://server/video.mp4
• Send a stream in realtime to a RTSP server, for others to watch:
ffmpeg -re -i <input> -f rtsp -muxdelay 0.1 rtsp://server/live.sdp
• Receive a stream in realtime:
ffmpeg -rtsp_flags listen -i rtsp://ownaddress/live.sdp <output>
sap
Session Announcement Protocol (RFC 2974). This is not technically a protocol handler in
libavformat, it is a muxer and demuxer. It is used for signalling of RTP streams, by
announcing the SDP for the streams regularly on a separate port.
Muxer
The syntax for a SAP url given to the muxer is:
sap://<destination>[:<port>][?<options>]
The RTP packets are sent to destination on port port, or to port 5004 if no port is
specified. options is a "&"-separated list. The following options are supported:
announce_addr=address
Specify the destination IP address for sending the announcements to. If omitted, the
announcements are sent to the commonly used SAP announcement multicast address
224.2.127.254 (sap.mcast.net), or ff0e::2:7ffe if destination is an IPv6 address.
announce_port=port
Specify the port to send the announcements on, defaults to 9875 if not specified.
ttl=ttl
Specify the time to live value for the announcements and RTP packets, defaults to 255.
same_port=0|1
If set to 1, send all RTP streams on the same port pair. If zero (the default), all
streams are sent on unique ports, with each stream on a port 2 numbers higher than the
previous. VLC/Live555 requires this to be set to 1, to be able to receive the stream.
The RTP stack in libavformat for receiving requires all streams to be sent on unique
ports.
Example command lines follow.
To broadcast a stream on the local subnet, for watching in VLC:
ffmpeg -re -i <input> -f sap sap://224.0.0.255?same_port=1
Similarly, for watching in ffplay:
ffmpeg -re -i <input> -f sap sap://224.0.0.255
And for watching in ffplay, over IPv6:
ffmpeg -re -i <input> -f sap sap://[ff0e::1:2:3:4]
Demuxer
The syntax for a SAP url given to the demuxer is:
sap://[<address>][:<port>]
address is the multicast address to listen for announcements on, if omitted, the default
224.2.127.254 (sap.mcast.net) is used. port is the port that is listened on, 9875 if
omitted.
The demuxers listens for announcements on the given address and port. Once an
announcement is received, it tries to receive that particular stream.
Example command lines follow.
To play back the first stream announced on the normal SAP multicast address:
ffplay sap://
To play back the first stream announced on one the default IPv6 SAP multicast address:
ffplay sap://[ff0e::2:7ffe]
sctp
Stream Control Transmission Protocol.
The accepted URL syntax is:
sctp://<host>:<port>[?<options>]
The protocol accepts the following options:
listen
If set to any value, listen for an incoming connection. Outgoing connection is done by
default.
max_streams
Set the maximum number of streams. By default no limit is set.
srt
Haivision Secure Reliable Transport Protocol via libsrt.
The supported syntax for a SRT URL is:
srt://<hostname>:<port>[?<options>]
options contains a list of &-separated options of the form key=val.
or
<options> srt://<hostname>:<port>
options contains a list of '-key val' options.
This protocol accepts the following options.
connect_timeout=milliseconds
Connection timeout; SRT cannot connect for RTT > 1500 msec (2 handshake exchanges)
with the default connect timeout of 3 seconds. This option applies to the caller and
rendezvous connection modes. The connect timeout is 10 times the value set for the
rendezvous mode (which can be used as a workaround for this connection problem with
earlier versions).
ffs=bytes
Flight Flag Size (Window Size), in bytes. FFS is actually an internal parameter and
you should set it to not less than recv_buffer_size and mss. The default value is
relatively large, therefore unless you set a very large receiver buffer, you do not
need to change this option. Default value is 25600.
inputbw=bytes/seconds
Sender nominal input rate, in bytes per seconds. Used along with oheadbw, when maxbw
is set to relative (0), to calculate maximum sending rate when recovery packets are
sent along with the main media stream: inputbw * (100 + oheadbw) / 100 if inputbw is
not set while maxbw is set to relative (0), the actual input rate is evaluated inside
the library. Default value is 0.
iptos=tos
IP Type of Service. Applies to sender only. Default value is 0xB8.
ipttl=ttl
IP Time To Live. Applies to sender only. Default value is 64.
latency=microseconds
Timestamp-based Packet Delivery Delay. Used to absorb bursts of missed packet
retransmissions. This flag sets both rcvlatency and peerlatency to the same value.
Note that prior to version 1.3.0 this is the only flag to set the latency, however
this is effectively equivalent to setting peerlatency, when side is sender and
rcvlatency when side is receiver, and the bidirectional stream sending is not
supported.
listen_timeout=microseconds
Set socket listen timeout.
maxbw=bytes/seconds
Maximum sending bandwidth, in bytes per seconds. -1 infinite (CSRTCC limit is 30mbps)
0 relative to input rate (see inputbw) >0 absolute limit value Default value is 0
(relative)
mode=caller|listener|rendezvous
Connection mode. caller opens client connection. listener starts server to listen
for incoming connections. rendezvous use Rendez-Vous connection mode. Default value
is caller.
mss=bytes
Maximum Segment Size, in bytes. Used for buffer allocation and rate calculation using
a packet counter assuming fully filled packets. The smallest MSS between the peers is
used. This is 1500 by default in the overall internet. This is the maximum size of
the UDP packet and can be only decreased, unless you have some unusual dedicated
network settings. Default value is 1500.
nakreport=1|0
If set to 1, Receiver will send `UMSG_LOSSREPORT` messages periodically until a lost
packet is retransmitted or intentionally dropped. Default value is 1.
oheadbw=percents
Recovery bandwidth overhead above input rate, in percents. See inputbw. Default value
is 25%.
passphrase=string
HaiCrypt Encryption/Decryption Passphrase string, length from 10 to 79 characters. The
passphrase is the shared secret between the sender and the receiver. It is used to
generate the Key Encrypting Key using PBKDF2 (Password-Based Key Derivation Function).
It is used only if pbkeylen is non-zero. It is used on the receiver only if the
received data is encrypted. The configured passphrase cannot be recovered (write-
only).
enforced_encryption=1|0
If true, both connection parties must have the same password set (including empty,
that is, with no encryption). If the password doesn't match or only one side is
unencrypted, the connection is rejected. Default is true.
kmrefreshrate=packets
The number of packets to be transmitted after which the encryption key is switched to
a new key. Default is -1. -1 means auto (0x1000000 in srt library). The range for
this option is integers in the 0 - "INT_MAX".
kmpreannounce=packets
The interval between when a new encryption key is sent and when switchover occurs.
This value also applies to the subsequent interval between when switchover occurs and
when the old encryption key is decommissioned. Default is -1. -1 means auto (0x1000
in srt library). The range for this option is integers in the 0 - "INT_MAX".
snddropdelay=microseconds
The sender's extra delay before dropping packets. This delay is added to the default
drop delay time interval value.
Special value -1: Do not drop packets on the sender at all.
payload_size=bytes
Sets the maximum declared size of a packet transferred during the single call to the
sending function in Live mode. Use 0 if this value isn't used (which is default in
file mode). Default is -1 (automatic), which typically means MPEG-TS; if you are
going to use SRT to send any different kind of payload, such as, for example, wrapping
a live stream in very small frames, then you can use a bigger maximum frame size,
though not greater than 1456 bytes.
pkt_size=bytes
Alias for payload_size.
peerlatency=microseconds
The latency value (as described in rcvlatency) that is set by the sender side as a
minimum value for the receiver.
pbkeylen=bytes
Sender encryption key length, in bytes. Only can be set to 0, 16, 24 and 32. Enable
sender encryption if not 0. Not required on receiver (set to 0), key size obtained
from sender in HaiCrypt handshake. Default value is 0.
rcvlatency=microseconds
The time that should elapse since the moment when the packet was sent and the moment
when it's delivered to the receiver application in the receiving function. This time
should be a buffer time large enough to cover the time spent for sending, unexpectedly
extended RTT time, and the time needed to retransmit the lost UDP packet. The
effective latency value will be the maximum of this options' value and the value of
peerlatency set by the peer side. Before version 1.3.0 this option is only available
as latency.
recv_buffer_size=bytes
Set UDP receive buffer size, expressed in bytes.
send_buffer_size=bytes
Set UDP send buffer size, expressed in bytes.
timeout=microseconds
Set raise error timeouts for read, write and connect operations. Note that the SRT
library has internal timeouts which can be controlled separately, the value set here
is only a cap on those.
tlpktdrop=1|0
Too-late Packet Drop. When enabled on receiver, it skips missing packets that have not
been delivered in time and delivers the following packets to the application when
their time-to-play has come. It also sends a fake ACK to the sender. When enabled on
sender and enabled on the receiving peer, the sender drops the older packets that have
no chance of being delivered in time. It was automatically enabled in the sender if
the receiver supports it.
sndbuf=bytes
Set send buffer size, expressed in bytes.
rcvbuf=bytes
Set receive buffer size, expressed in bytes.
Receive buffer must not be greater than ffs.
lossmaxttl=packets
The value up to which the Reorder Tolerance may grow. When Reorder Tolerance is > 0,
then packet loss report is delayed until that number of packets come in. Reorder
Tolerance increases every time a "belated" packet has come, but it wasn't due to
retransmission (that is, when UDP packets tend to come out of order), with the
difference between the latest sequence and this packet's sequence, and not more than
the value of this option. By default it's 0, which means that this mechanism is turned
off, and the loss report is always sent immediately upon experiencing a "gap" in
sequences.
minversion
The minimum SRT version that is required from the peer. A connection to a peer that
does not satisfy the minimum version requirement will be rejected.
The version format in hex is 0xXXYYZZ for x.y.z in human readable form.
streamid=string
A string limited to 512 characters that can be set on the socket prior to connecting.
This stream ID will be able to be retrieved by the listener side from the socket that
is returned from srt_accept and was connected by a socket with that set stream ID. SRT
does not enforce any special interpretation of the contents of this string. This
option doesn’t make sense in Rendezvous connection; the result might be that simply
one side will override the value from the other side and it’s the matter of luck which
one would win
srt_streamid=string
Alias for streamid to avoid conflict with ffmpeg command line option.
smoother=live|file
The type of Smoother used for the transmission for that socket, which is responsible
for the transmission and congestion control. The Smoother type must be exactly the
same on both connecting parties, otherwise the connection is rejected.
messageapi=1|0
When set, this socket uses the Message API, otherwise it uses Buffer API. Note that in
live mode (see transtype) there’s only message API available. In File mode you can
chose to use one of two modes:
Stream API (default, when this option is false). In this mode you may send as many
data as you wish with one sending instruction, or even use dedicated functions that
read directly from a file. The internal facility will take care of any speed and
congestion control. When receiving, you can also receive as many data as desired, the
data not extracted will be waiting for the next call. There is no boundary between
data portions in the Stream mode.
Message API. In this mode your single sending instruction passes exactly one piece of
data that has boundaries (a message). Contrary to Live mode, this message may span
across multiple UDP packets and the only size limitation is that it shall fit as a
whole in the sending buffer. The receiver shall use as large buffer as necessary to
receive the message, otherwise the message will not be given up. When the message is
not complete (not all packets received or there was a packet loss) it will not be
given up.
transtype=live|file
Sets the transmission type for the socket, in particular, setting this option sets
multiple other parameters to their default values as required for a particular
transmission type.
live: Set options as for live transmission. In this mode, you should send by one
sending instruction only so many data that fit in one UDP packet, and limited to the
value defined first in payload_size (1316 is default in this mode). There is no speed
control in this mode, only the bandwidth control, if configured, in order to not
exceed the bandwidth with the overhead transmission (retransmitted and control
packets).
file: Set options as for non-live transmission. See messageapi for further
explanations
linger=seconds
The number of seconds that the socket waits for unsent data when closing. Default is
-1. -1 means auto (off with 0 seconds in live mode, on with 180 seconds in file mode).
The range for this option is integers in the 0 - "INT_MAX".
tsbpd=1|0
When true, use Timestamp-based Packet Delivery mode. The default behavior depends on
the transmission type: enabled in live mode, disabled in file mode.
For more information see: <https://github.com/Haivision/srt>.
srtp
Secure Real-time Transport Protocol.
The accepted options are:
srtp_in_suite
srtp_out_suite
Select input and output encoding suites.
Supported values:
AES_CM_128_HMAC_SHA1_80
SRTP_AES128_CM_HMAC_SHA1_80
AES_CM_128_HMAC_SHA1_32
SRTP_AES128_CM_HMAC_SHA1_32
srtp_in_params
srtp_out_params
Set input and output encoding parameters, which are expressed by a base64-encoded
representation of a binary block. The first 16 bytes of this binary block are used as
master key, the following 14 bytes are used as master salt.
subfile
Virtually extract a segment of a file or another stream. The underlying stream must be
seekable.
Accepted options:
start
Start offset of the extracted segment, in bytes.
end End offset of the extracted segment, in bytes. If set to 0, extract till end of file.
Examples:
Extract a chapter from a DVD VOB file (start and end sectors obtained externally and
multiplied by 2048):
subfile,,start,153391104,end,268142592,,:/media/dvd/VIDEO_TS/VTS_08_1.VOB
Play an AVI file directly from a TAR archive:
subfile,,start,183241728,end,366490624,,:archive.tar
Play a MPEG-TS file from start offset till end:
subfile,,start,32815239,end,0,,:video.ts
tee
Writes the output to multiple protocols. The individual outputs are separated by |
tee:file://path/to/local/this.avi|file://path/to/local/that.avi
tcp
Transmission Control Protocol.
The required syntax for a TCP url is:
tcp://<hostname>:<port>[?<options>]
options contains a list of &-separated options of the form key=val.
The list of supported options follows.
listen=2|1|0
Listen for an incoming connection. 0 disables listen, 1 enables listen in single
client mode, 2 enables listen in multi-client mode. Default value is 0.
local_addr=addr
Local IP address of a network interface used for tcp socket connect.
local_port=port
Local port used for tcp socket connect.
timeout=microseconds
Set raise error timeout, expressed in microseconds.
This option is only relevant in read mode: if no data arrived in more than this time
interval, raise error.
listen_timeout=milliseconds
Set listen timeout, expressed in milliseconds.
recv_buffer_size=bytes
Set receive buffer size, expressed bytes.
send_buffer_size=bytes
Set send buffer size, expressed bytes.
tcp_nodelay=1|0
Set TCP_NODELAY to disable Nagle's algorithm. Default value is 0.
Remark: Writing to the socket is currently not optimized to minimize system calls and
reduces the efficiency / effect of TCP_NODELAY.
tcp_mss=bytes
Set maximum segment size for outgoing TCP packets, expressed in bytes.
The following example shows how to setup a listening TCP connection with ffmpeg, which is
then accessed with ffplay:
ffmpeg -i <input> -f <format> tcp://<hostname>:<port>?listen
ffplay tcp://<hostname>:<port>
tls
Transport Layer Security (TLS) / Secure Sockets Layer (SSL)
The required syntax for a TLS/SSL url is:
tls://<hostname>:<port>[?<options>]
The following parameters can be set via command line options (or in code via "AVOption"s):
ca_file, cafile=filename
A file containing certificate authority (CA) root certificates to treat as trusted. If
the linked TLS library contains a default this might not need to be specified for
verification to work, but not all libraries and setups have defaults built in. The
file must be in OpenSSL PEM format.
tls_verify=1|0
If enabled, try to verify the peer that we are communicating with. Note, if using
OpenSSL, this currently only makes sure that the peer certificate is signed by one of
the root certificates in the CA database, but it does not validate that the
certificate actually matches the host name we are trying to connect to. (With other
backends, the host name is validated as well.)
This is disabled by default since it requires a CA database to be provided by the
caller in many cases.
cert_file, cert=filename
A file containing a certificate to use in the handshake with the peer. (When
operating as server, in listen mode, this is more often required by the peer, while
client certificates only are mandated in certain setups.)
key_file, key=filename
A file containing the private key for the certificate.
listen=1|0
If enabled, listen for connections on the provided port, and assume the server role in
the handshake instead of the client role.
http_proxy
The HTTP proxy to tunnel through, e.g. "http://example.com:1234". The proxy must
support the CONNECT method.
Example command lines:
To create a TLS/SSL server that serves an input stream.
ffmpeg -i <input> -f <format> tls://<hostname>:<port>?listen&cert=<server.crt>&key=<server.key>
To play back a stream from the TLS/SSL server using ffplay:
ffplay tls://<hostname>:<port>
udp
User Datagram Protocol.
The required syntax for an UDP URL is:
udp://<hostname>:<port>[?<options>]
options contains a list of &-separated options of the form key=val.
In case threading is enabled on the system, a circular buffer is used to store the
incoming data, which allows one to reduce loss of data due to UDP socket buffer overruns.
The fifo_size and overrun_nonfatal options are related to this buffer.
The list of supported options follows.
buffer_size=size
Set the UDP maximum socket buffer size in bytes. This is used to set either the
receive or send buffer size, depending on what the socket is used for. Default is 32
KB for output, 384 KB for input. See also fifo_size.
bitrate=bitrate
If set to nonzero, the output will have the specified constant bitrate if the input
has enough packets to sustain it.
burst_bits=bits
When using bitrate this specifies the maximum number of bits in packet bursts.
localport=port
Override the local UDP port to bind with.
localaddr=addr
Local IP address of a network interface used for sending packets or joining multicast
groups.
pkt_size=size
Set the size in bytes of UDP packets.
reuse=1|0
Explicitly allow or disallow reusing UDP sockets.
ttl=ttl
Set the time to live value (for multicast only).
connect=1|0
Initialize the UDP socket with connect(). In this case, the destination address can't
be changed with ff_udp_set_remote_url later. If the destination address isn't known
at the start, this option can be specified in ff_udp_set_remote_url, too. This allows
finding out the source address for the packets with getsockname, and makes writes
return with AVERROR(ECONNREFUSED) if "destination unreachable" is received. For
receiving, this gives the benefit of only receiving packets from the specified peer
address/port.
sources=address[,address]
Only receive packets sent from the specified addresses. In case of multicast, also
subscribe to multicast traffic coming from these addresses only.
block=address[,address]
Ignore packets sent from the specified addresses. In case of multicast, also exclude
the source addresses in the multicast subscription.
fifo_size=units
Set the UDP receiving circular buffer size, expressed as a number of packets with size
of 188 bytes. If not specified defaults to 7*4096.
overrun_nonfatal=1|0
Survive in case of UDP receiving circular buffer overrun. Default value is 0.
timeout=microseconds
Set raise error timeout, expressed in microseconds.
This option is only relevant in read mode: if no data arrived in more than this time
interval, raise error.
broadcast=1|0
Explicitly allow or disallow UDP broadcasting.
Note that broadcasting may not work properly on networks having a broadcast storm
protection.
Examples
• Use ffmpeg to stream over UDP to a remote endpoint:
ffmpeg -i <input> -f <format> udp://<hostname>:<port>
• Use ffmpeg to stream in mpegts format over UDP using 188 sized UDP packets, using a
large input buffer:
ffmpeg -i <input> -f mpegts udp://<hostname>:<port>?pkt_size=188&buffer_size=65535
• Use ffmpeg to receive over UDP from a remote endpoint:
ffmpeg -i udp://[<multicast-address>]:<port> ...
unix
Unix local socket
The required syntax for a Unix socket URL is:
unix://<filepath>
The following parameters can be set via command line options (or in code via "AVOption"s):
timeout
Timeout in ms.
listen
Create the Unix socket in listening mode.
zmq
ZeroMQ asynchronous messaging using the libzmq library.
This library supports unicast streaming to multiple clients without relying on an external
server.
The required syntax for streaming or connecting to a stream is:
zmq:tcp://ip-address:port
Example: Create a localhost stream on port 5555:
ffmpeg -re -i input -f mpegts zmq:tcp://127.0.0.1:5555
Multiple clients may connect to the stream using:
ffplay zmq:tcp://127.0.0.1:5555
Streaming to multiple clients is implemented using a ZeroMQ Pub-Sub pattern. The server
side binds to a port and publishes data. Clients connect to the server (via IP
address/port) and subscribe to the stream. The order in which the server and client start
generally does not matter.
ffmpeg must be compiled with the --enable-libzmq option to support this protocol.
Options can be set on the ffmpeg/ffplay command line. The following options are supported:
pkt_size
Forces the maximum packet size for sending/receiving data. The default value is
131,072 bytes. On the server side, this sets the maximum size of sent packets via
ZeroMQ. On the clients, it sets an internal buffer size for receiving packets. Note
that pkt_size on the clients should be equal to or greater than pkt_size on the
server. Otherwise the received message may be truncated causing decoding errors.
DEVICE OPTIONS
The libavdevice library provides the same interface as libavformat. Namely, an input
device is considered like a demuxer, and an output device like a muxer, and the interface
and generic device options are the same provided by libavformat (see the ffmpeg-formats
manual).
In addition each input or output device may support so-called private options, which are
specific for that component.
Options may be set by specifying -option value in the FFmpeg tools, or by setting the
value explicitly in the device "AVFormatContext" options or using the libavutil/opt.h API
for programmatic use.
INPUT DEVICES
Input devices are configured elements in FFmpeg which enable accessing the data coming
from a multimedia device attached to your system.
When you configure your FFmpeg build, all the supported input devices are enabled by
default. You can list all available ones using the configure option "--list-indevs".
You can disable all the input devices using the configure option "--disable-indevs", and
selectively enable an input device using the option "--enable-indev=INDEV", or you can
disable a particular input device using the option "--disable-indev=INDEV".
The option "-devices" of the ff* tools will display the list of supported input devices.
A description of the currently available input devices follows.
alsa
ALSA (Advanced Linux Sound Architecture) input device.
To enable this input device during configuration you need libasound installed on your
system.
This device allows capturing from an ALSA device. The name of the device to capture has to
be an ALSA card identifier.
An ALSA identifier has the syntax:
hw:<CARD>[,<DEV>[,<SUBDEV>]]
where the DEV and SUBDEV components are optional.
The three arguments (in order: CARD,DEV,SUBDEV) specify card number or identifier, device
number and subdevice number (-1 means any).
To see the list of cards currently recognized by your system check the files
/proc/asound/cards and /proc/asound/devices.
For example to capture with ffmpeg from an ALSA device with card id 0, you may run the
command:
ffmpeg -f alsa -i hw:0 alsaout.wav
For more information see: <http://www.alsa-project.org/alsa-doc/alsa-lib/pcm.html>
Options
sample_rate
Set the sample rate in Hz. Default is 48000.
channels
Set the number of channels. Default is 2.
android_camera
Android camera input device.
This input devices uses the Android Camera2 NDK API which is available on devices with API
level 24+. The availability of android_camera is autodetected during configuration.
This device allows capturing from all cameras on an Android device, which are integrated
into the Camera2 NDK API.
The available cameras are enumerated internally and can be selected with the camera_index
parameter. The input file string is discarded.
Generally the back facing camera has index 0 while the front facing camera has index 1.
Options
video_size
Set the video size given as a string such as 640x480 or hd720. Falls back to the
first available configuration reported by Android if requested video size is not
available or by default.
framerate
Set the video framerate. Falls back to the first available configuration reported by
Android if requested framerate is not available or by default (-1).
camera_index
Set the index of the camera to use. Default is 0.
input_queue_size
Set the maximum number of frames to buffer. Default is 5.
avfoundation
AVFoundation input device.
AVFoundation is the currently recommended framework by Apple for streamgrabbing on OSX >=
10.7 as well as on iOS.
The input filename has to be given in the following syntax:
-i "[[VIDEO]:[AUDIO]]"
The first entry selects the video input while the latter selects the audio input. The
stream has to be specified by the device name or the device index as shown by the device
list. Alternatively, the video and/or audio input device can be chosen by index using the
B<-video_device_index E<lt>INDEXE<gt>>
and/or
B<-audio_device_index E<lt>INDEXE<gt>>
, overriding any device name or index given in the input filename.
All available devices can be enumerated by using -list_devices true, listing all device
names and corresponding indices.
There are two device name aliases:
"default"
Select the AVFoundation default device of the corresponding type.
"none"
Do not record the corresponding media type. This is equivalent to specifying an empty
device name or index.
Options
AVFoundation supports the following options:
-list_devices <TRUE|FALSE>
If set to true, a list of all available input devices is given showing all device
names and indices.
-video_device_index <INDEX>
Specify the video device by its index. Overrides anything given in the input filename.
-audio_device_index <INDEX>
Specify the audio device by its index. Overrides anything given in the input filename.
-pixel_format <FORMAT>
Request the video device to use a specific pixel format. If the specified format is
not supported, a list of available formats is given and the first one in this list is
used instead. Available pixel formats are: "monob, rgb555be, rgb555le, rgb565be,
rgb565le, rgb24, bgr24, 0rgb, bgr0, 0bgr, rgb0,
bgr48be, uyvy422, yuva444p, yuva444p16le, yuv444p, yuv422p16, yuv422p10, yuv444p10,
yuv420p, nv12, yuyv422, gray"
-framerate
Set the grabbing frame rate. Default is "ntsc", corresponding to a frame rate of
"30000/1001".
-video_size
Set the video frame size.
-capture_cursor
Capture the mouse pointer. Default is 0.
-capture_mouse_clicks
Capture the screen mouse clicks. Default is 0.
-capture_raw_data
Capture the raw device data. Default is 0. Using this option may result in receiving
the underlying data delivered to the AVFoundation framework. E.g. for muxed devices
that sends raw DV data to the framework (like tape-based camcorders), setting this
option to false results in extracted video frames captured in the designated pixel
format only. Setting this option to true results in receiving the raw DV stream
untouched.
Examples
• Print the list of AVFoundation supported devices and exit:
$ ffmpeg -f avfoundation -list_devices true -i ""
• Record video from video device 0 and audio from audio device 0 into out.avi:
$ ffmpeg -f avfoundation -i "0:0" out.avi
• Record video from video device 2 and audio from audio device 1 into out.avi:
$ ffmpeg -f avfoundation -video_device_index 2 -i ":1" out.avi
• Record video from the system default video device using the pixel format bgr0 and do
not record any audio into out.avi:
$ ffmpeg -f avfoundation -pixel_format bgr0 -i "default:none" out.avi
• Record raw DV data from a suitable input device and write the output into out.dv:
$ ffmpeg -f avfoundation -capture_raw_data true -i "zr100:none" out.dv
bktr
BSD video input device. Deprecated and will be removed - please contact the developers if
you are interested in maintaining it.
Options
framerate
Set the frame rate.
video_size
Set the video frame size. Default is "vga".
standard
Available values are:
pal
ntsc
secam
paln
palm
ntscj
decklink
The decklink input device provides capture capabilities for Blackmagic DeckLink devices.
To enable this input device, you need the Blackmagic DeckLink SDK and you need to
configure with the appropriate "--extra-cflags" and "--extra-ldflags". On Windows, you
need to run the IDL files through widl.
DeckLink is very picky about the formats it supports. Pixel format of the input can be set
with raw_format. Framerate and video size must be determined for your device with
-list_formats 1. Audio sample rate is always 48 kHz and the number of channels can be 2, 8
or 16. Note that all audio channels are bundled in one single audio track.
Options
list_devices
If set to true, print a list of devices and exit. Defaults to false. This option is
deprecated, please use the "-sources" option of ffmpeg to list the available input
devices.
list_formats
If set to true, print a list of supported formats and exit. Defaults to false.
format_code <FourCC>
This sets the input video format to the format given by the FourCC. To see the
supported values of your device(s) use list_formats. Note that there is a FourCC 'pal
' that can also be used as pal (3 letters). Default behavior is autodetection of the
input video format, if the hardware supports it.
raw_format
Set the pixel format of the captured video. Available values are:
auto
This is the default which means 8-bit YUV 422 or 8-bit ARGB if format
autodetection is used, 8-bit YUV 422 otherwise.
uyvy422
8-bit YUV 422.
yuv422p10
10-bit YUV 422.
argb
8-bit RGB.
bgra
8-bit RGB.
rgb10
10-bit RGB.
teletext_lines
If set to nonzero, an additional teletext stream will be captured from the vertical
ancillary data. Both SD PAL (576i) and HD (1080i or 1080p) sources are supported. In
case of HD sources, OP47 packets are decoded.
This option is a bitmask of the SD PAL VBI lines captured, specifically lines 6 to 22,
and lines 318 to 335. Line 6 is the LSB in the mask. Selected lines which do not
contain teletext information will be ignored. You can use the special all constant to
select all possible lines, or standard to skip lines 6, 318 and 319, which are not
compatible with all receivers.
For SD sources, ffmpeg needs to be compiled with "--enable-libzvbi". For HD sources,
on older (pre-4K) DeckLink card models you have to capture in 10 bit mode.
channels
Defines number of audio channels to capture. Must be 2, 8 or 16. Defaults to 2.
duplex_mode
Sets the decklink device duplex/profile mode. Must be unset, half, full,
one_sub_device_full, one_sub_device_half, two_sub_device_full, four_sub_device_half
Defaults to unset.
Note: DeckLink SDK 11.0 have replaced the duplex property by a profile property. For
the DeckLink Duo 2 and DeckLink Quad 2, a profile is shared between any 2 sub-devices
that utilize the same connectors. For the DeckLink 8K Pro, a profile is shared between
all 4 sub-devices. So DeckLink 8K Pro support four profiles.
Valid profile modes for DeckLink 8K Pro(with DeckLink SDK >= 11.0):
one_sub_device_full, one_sub_device_half, two_sub_device_full, four_sub_device_half
Valid profile modes for DeckLink Quad 2 and DeckLink Duo 2: half, full
timecode_format
Timecode type to include in the frame and video stream metadata. Must be none,
rp188vitc, rp188vitc2, rp188ltc, rp188hfr, rp188any, vitc, vitc2, or serial. Defaults
to none (not included).
In order to properly support 50/60 fps timecodes, the ordering of the queried timecode
types for rp188any is HFR, VITC1, VITC2 and LTC for >30 fps content. Note that this is
slightly different to the ordering used by the DeckLink API, which is HFR, VITC1, LTC,
VITC2.
video_input
Sets the video input source. Must be unset, sdi, hdmi, optical_sdi, component,
composite or s_video. Defaults to unset.
audio_input
Sets the audio input source. Must be unset, embedded, aes_ebu, analog, analog_xlr,
analog_rca or microphone. Defaults to unset.
video_pts
Sets the video packet timestamp source. Must be video, audio, reference, wallclock or
abs_wallclock. Defaults to video.
audio_pts
Sets the audio packet timestamp source. Must be video, audio, reference, wallclock or
abs_wallclock. Defaults to audio.
draw_bars
If set to true, color bars are drawn in the event of a signal loss. Defaults to true.
This option is deprecated, please use the "signal_loss_action" option.
signal_loss_action
Sets the action to take in the event of a signal loss. Accepts one of the following
values:
1, none
Do nothing on signal loss. This usually results in black frames.
2, bars
Draw color bars on signal loss. Only supported for 8-bit input signals.
3, repeat
Repeat the last video frame on signal loss.
Defaults to bars.
queue_size
Sets maximum input buffer size in bytes. If the buffering reaches this value, incoming
frames will be dropped. Defaults to 1073741824.
audio_depth
Sets the audio sample bit depth. Must be 16 or 32. Defaults to 16.
decklink_copyts
If set to true, timestamps are forwarded as they are without removing the initial
offset. Defaults to false.
timestamp_align
Capture start time alignment in seconds. If set to nonzero, input frames are dropped
till the system timestamp aligns with configured value. Alignment difference of up to
one frame duration is tolerated. This is useful for maintaining input synchronization
across N different hardware devices deployed for 'N-way' redundancy. The system time
of different hardware devices should be synchronized with protocols such as NTP or
PTP, before using this option. Note that this method is not foolproof. In some border
cases input synchronization may not happen due to thread scheduling jitters in the OS.
Either sync could go wrong by 1 frame or in a rarer case timestamp_align seconds.
Defaults to 0.
wait_for_tc (bool)
Drop frames till a frame with timecode is received. Sometimes serial timecode isn't
received with the first input frame. If that happens, the stored stream timecode will
be inaccurate. If this option is set to true, input frames are dropped till a frame
with timecode is received. Option timecode_format must be specified. Defaults to
false.
enable_klv(bool)
If set to true, extracts KLV data from VANC and outputs KLV packets. KLV VANC packets
are joined based on MID and PSC fields and aggregated into one KLV packet. Defaults
to false.
Examples
• List input devices:
ffmpeg -sources decklink
• List supported formats:
ffmpeg -f decklink -list_formats 1 -i 'Intensity Pro'
• Capture video clip at 1080i50:
ffmpeg -format_code Hi50 -f decklink -i 'Intensity Pro' -c:a copy -c:v copy output.avi
• Capture video clip at 1080i50 10 bit:
ffmpeg -raw_format yuv422p10 -format_code Hi50 -f decklink -i 'UltraStudio Mini Recorder' -c:a copy -c:v copy output.avi
• Capture video clip at 1080i50 with 16 audio channels:
ffmpeg -channels 16 -format_code Hi50 -f decklink -i 'UltraStudio Mini Recorder' -c:a copy -c:v copy output.avi
dshow
Windows DirectShow input device.
DirectShow support is enabled when FFmpeg is built with the mingw-w64 project. Currently
only audio and video devices are supported.
Multiple devices may be opened as separate inputs, but they may also be opened on the same
input, which should improve synchronism between them.
The input name should be in the format:
<TYPE>=<NAME>[:<TYPE>=<NAME>]
where TYPE can be either audio or video, and NAME is the device's name or alternative
name..
Options
If no options are specified, the device's defaults are used. If the device does not
support the requested options, it will fail to open.
video_size
Set the video size in the captured video.
framerate
Set the frame rate in the captured video.
sample_rate
Set the sample rate (in Hz) of the captured audio.
sample_size
Set the sample size (in bits) of the captured audio.
channels
Set the number of channels in the captured audio.
list_devices
If set to true, print a list of devices and exit.
list_options
If set to true, print a list of selected device's options and exit.
video_device_number
Set video device number for devices with the same name (starts at 0, defaults to 0).
audio_device_number
Set audio device number for devices with the same name (starts at 0, defaults to 0).
pixel_format
Select pixel format to be used by DirectShow. This may only be set when the video
codec is not set or set to rawvideo.
audio_buffer_size
Set audio device buffer size in milliseconds (which can directly impact latency,
depending on the device). Defaults to using the audio device's default buffer size
(typically some multiple of 500ms). Setting this value too low can degrade
performance. See also
<http://msdn.microsoft.com/en-us/library/windows/desktop/dd377582(v=vs.85).aspx>
video_pin_name
Select video capture pin to use by name or alternative name.
audio_pin_name
Select audio capture pin to use by name or alternative name.
crossbar_video_input_pin_number
Select video input pin number for crossbar device. This will be routed to the crossbar
device's Video Decoder output pin. Note that changing this value can affect future
invocations (sets a new default) until system reboot occurs.
crossbar_audio_input_pin_number
Select audio input pin number for crossbar device. This will be routed to the crossbar
device's Audio Decoder output pin. Note that changing this value can affect future
invocations (sets a new default) until system reboot occurs.
show_video_device_dialog
If set to true, before capture starts, popup a display dialog to the end user,
allowing them to change video filter properties and configurations manually. Note
that for crossbar devices, adjusting values in this dialog may be needed at times to
toggle between PAL (25 fps) and NTSC (29.97) input frame rates, sizes, interlacing,
etc. Changing these values can enable different scan rates/frame rates and avoiding
green bars at the bottom, flickering scan lines, etc. Note that with some devices,
changing these properties can also affect future invocations (sets new defaults) until
system reboot occurs.
show_audio_device_dialog
If set to true, before capture starts, popup a display dialog to the end user,
allowing them to change audio filter properties and configurations manually.
show_video_crossbar_connection_dialog
If set to true, before capture starts, popup a display dialog to the end user,
allowing them to manually modify crossbar pin routings, when it opens a video device.
show_audio_crossbar_connection_dialog
If set to true, before capture starts, popup a display dialog to the end user,
allowing them to manually modify crossbar pin routings, when it opens an audio device.
show_analog_tv_tuner_dialog
If set to true, before capture starts, popup a display dialog to the end user,
allowing them to manually modify TV channels and frequencies.
show_analog_tv_tuner_audio_dialog
If set to true, before capture starts, popup a display dialog to the end user,
allowing them to manually modify TV audio (like mono vs. stereo, Language A,B or C).
audio_device_load
Load an audio capture filter device from file instead of searching it by name. It may
load additional parameters too, if the filter supports the serialization of its
properties to. To use this an audio capture source has to be specified, but it can be
anything even fake one.
audio_device_save
Save the currently used audio capture filter device and its parameters (if the filter
supports it) to a file. If a file with the same name exists it will be overwritten.
video_device_load
Load a video capture filter device from file instead of searching it by name. It may
load additional parameters too, if the filter supports the serialization of its
properties to. To use this a video capture source has to be specified, but it can be
anything even fake one.
video_device_save
Save the currently used video capture filter device and its parameters (if the filter
supports it) to a file. If a file with the same name exists it will be overwritten.
use_video_device_timestamps
If set to false, the timestamp for video frames will be derived from the wallclock
instead of the timestamp provided by the capture device. This allows working around
devices that provide unreliable timestamps.
Examples
• Print the list of DirectShow supported devices and exit:
$ ffmpeg -list_devices true -f dshow -i dummy
• Open video device Camera:
$ ffmpeg -f dshow -i video="Camera"
• Open second video device with name Camera:
$ ffmpeg -f dshow -video_device_number 1 -i video="Camera"
• Open video device Camera and audio device Microphone:
$ ffmpeg -f dshow -i video="Camera":audio="Microphone"
• Print the list of supported options in selected device and exit:
$ ffmpeg -list_options true -f dshow -i video="Camera"
• Specify pin names to capture by name or alternative name, specify alternative device
name:
$ ffmpeg -f dshow -audio_pin_name "Audio Out" -video_pin_name 2 -i video=video="@device_pnp_\\?\pci#ven_1a0a&dev_6200&subsys_62021461&rev_01#4&e2c7dd6&0&00e1#{65e8773d-8f56-11d0-a3b9-00a0c9223196}\{ca465100-deb0-4d59-818f-8c477184adf6}":audio="Microphone"
• Configure a crossbar device, specifying crossbar pins, allow user to adjust video
capture properties at startup:
$ ffmpeg -f dshow -show_video_device_dialog true -crossbar_video_input_pin_number 0
-crossbar_audio_input_pin_number 3 -i video="AVerMedia BDA Analog Capture":audio="AVerMedia BDA Analog Capture"
fbdev
Linux framebuffer input device.
The Linux framebuffer is a graphic hardware-independent abstraction layer to show graphics
on a computer monitor, typically on the console. It is accessed through a file device
node, usually /dev/fb0.
For more detailed information read the file Documentation/fb/framebuffer.txt included in
the Linux source tree.
See also <http://linux-fbdev.sourceforge.net/>, and fbset(1).
To record from the framebuffer device /dev/fb0 with ffmpeg:
ffmpeg -f fbdev -framerate 10 -i /dev/fb0 out.avi
You can take a single screenshot image with the command:
ffmpeg -f fbdev -framerate 1 -i /dev/fb0 -frames:v 1 screenshot.jpeg
Options
framerate
Set the frame rate. Default is 25.
gdigrab
Win32 GDI-based screen capture device.
This device allows you to capture a region of the display on Windows.
Amongst options for the imput filenames are such elements as:
desktop
or
title=<window_title>
or
hwnd=<window_hwnd>
The first option will capture the entire desktop, or a fixed region of the desktop. The
second and third options will instead capture the contents of a single window, regardless
of its position on the screen.
For example, to grab the entire desktop using ffmpeg:
ffmpeg -f gdigrab -framerate 6 -i desktop out.mpg
Grab a 640x480 region at position "10,20":
ffmpeg -f gdigrab -framerate 6 -offset_x 10 -offset_y 20 -video_size vga -i desktop out.mpg
Grab the contents of the window named "Calculator"
ffmpeg -f gdigrab -framerate 6 -i title=Calculator out.mpg
Options
draw_mouse
Specify whether to draw the mouse pointer. Use the value 0 to not draw the pointer.
Default value is 1.
framerate
Set the grabbing frame rate. Default value is "ntsc", corresponding to a frame rate of
"30000/1001".
show_region
Show grabbed region on screen.
If show_region is specified with 1, then the grabbing region will be indicated on
screen. With this option, it is easy to know what is being grabbed if only a portion
of the screen is grabbed.
Note that show_region is incompatible with grabbing the contents of a single window.
For example:
ffmpeg -f gdigrab -show_region 1 -framerate 6 -video_size cif -offset_x 10 -offset_y 20 -i desktop out.mpg
video_size
Set the video frame size. The default is to capture the full screen if desktop is
selected, or the full window size if title=window_title is selected.
offset_x
When capturing a region with video_size, set the distance from the left edge of the
screen or desktop.
Note that the offset calculation is from the top left corner of the primary monitor on
Windows. If you have a monitor positioned to the left of your primary monitor, you
will need to use a negative offset_x value to move the region to that monitor.
offset_y
When capturing a region with video_size, set the distance from the top edge of the
screen or desktop.
Note that the offset calculation is from the top left corner of the primary monitor on
Windows. If you have a monitor positioned above your primary monitor, you will need to
use a negative offset_y value to move the region to that monitor.
iec61883
FireWire DV/HDV input device using libiec61883.
To enable this input device, you need libiec61883, libraw1394 and libavc1394 installed on
your system. Use the configure option "--enable-libiec61883" to compile with the device
enabled.
The iec61883 capture device supports capturing from a video device connected via IEEE1394
(FireWire), using libiec61883 and the new Linux FireWire stack (juju). This is the default
DV/HDV input method in Linux Kernel 2.6.37 and later, since the old FireWire stack was
removed.
Specify the FireWire port to be used as input file, or "auto" to choose the first port
connected.
Options
dvtype
Override autodetection of DV/HDV. This should only be used if auto detection does not
work, or if usage of a different device type should be prohibited. Treating a DV
device as HDV (or vice versa) will not work and result in undefined behavior. The
values auto, dv and hdv are supported.
dvbuffer
Set maximum size of buffer for incoming data, in frames. For DV, this is an exact
value. For HDV, it is not frame exact, since HDV does not have a fixed frame size.
dvguid
Select the capture device by specifying its GUID. Capturing will only be performed
from the specified device and fails if no device with the given GUID is found. This is
useful to select the input if multiple devices are connected at the same time. Look
at /sys/bus/firewire/devices to find out the GUIDs.
Examples
• Grab and show the input of a FireWire DV/HDV device.
ffplay -f iec61883 -i auto
• Grab and record the input of a FireWire DV/HDV device, using a packet buffer of 100000
packets if the source is HDV.
ffmpeg -f iec61883 -i auto -dvbuffer 100000 out.mpg
jack
JACK input device.
To enable this input device during configuration you need libjack installed on your
system.
A JACK input device creates one or more JACK writable clients, one for each audio channel,
with name client_name:input_N, where client_name is the name provided by the application,
and N is a number which identifies the channel. Each writable client will send the
acquired data to the FFmpeg input device.
Once you have created one or more JACK readable clients, you need to connect them to one
or more JACK writable clients.
To connect or disconnect JACK clients you can use the jack_connect and jack_disconnect
programs, or do it through a graphical interface, for example with qjackctl.
To list the JACK clients and their properties you can invoke the command jack_lsp.
Follows an example which shows how to capture a JACK readable client with ffmpeg.
# Create a JACK writable client with name "ffmpeg".
$ ffmpeg -f jack -i ffmpeg -y out.wav
# Start the sample jack_metro readable client.
$ jack_metro -b 120 -d 0.2 -f 4000
# List the current JACK clients.
$ jack_lsp -c
system:capture_1
system:capture_2
system:playback_1
system:playback_2
ffmpeg:input_1
metro:120_bpm
# Connect metro to the ffmpeg writable client.
$ jack_connect metro:120_bpm ffmpeg:input_1
For more information read: <http://jackaudio.org/>
Options
channels
Set the number of channels. Default is 2.
kmsgrab
KMS video input device.
Captures the KMS scanout framebuffer associated with a specified CRTC or plane as a DRM
object that can be passed to other hardware functions.
Requires either DRM master or CAP_SYS_ADMIN to run.
If you don't understand what all of that means, you probably don't want this. Look at
x11grab instead.
Options
device
DRM device to capture on. Defaults to /dev/dri/card0.
format
Pixel format of the framebuffer. This can be autodetected if you are running Linux
5.7 or later, but needs to be provided for earlier versions. Defaults to bgr0, which
is the most common format used by the Linux console and Xorg X server.
format_modifier
Format modifier to signal on output frames. This is necessary to import correctly
into some APIs. It can be autodetected if you are running Linux 5.7 or later, but
will need to be provided explicitly when needed in earlier versions. See the libdrm
documentation for possible values.
crtc_id
KMS CRTC ID to define the capture source. The first active plane on the given CRTC
will be used.
plane_id
KMS plane ID to define the capture source. Defaults to the first active plane found
if neither crtc_id nor plane_id are specified.
framerate
Framerate to capture at. This is not synchronised to any page flipping or framebuffer
changes - it just defines the interval at which the framebuffer is sampled. Sampling
faster than the framebuffer update rate will generate independent frames with the same
content. Defaults to 30.
Examples
• Capture from the first active plane, download the result to normal frames and encode.
This will only work if the framebuffer is both linear and mappable - if not, the
result may be scrambled or fail to download.
ffmpeg -f kmsgrab -i - -vf 'hwdownload,format=bgr0' output.mp4
• Capture from CRTC ID 42 at 60fps, map the result to VAAPI, convert to NV12 and encode
as H.264.
ffmpeg -crtc_id 42 -framerate 60 -f kmsgrab -i - -vf 'hwmap=derive_device=vaapi,scale_vaapi=w=1920:h=1080:format=nv12' -c:v h264_vaapi output.mp4
• To capture only part of a plane the output can be cropped - this can be used to
capture a single window, as long as it has a known absolute position and size. For
example, to capture and encode the middle quarter of a 1920x1080 plane:
ffmpeg -f kmsgrab -i - -vf 'hwmap=derive_device=vaapi,crop=960:540:480:270,scale_vaapi=960:540:nv12' -c:v h264_vaapi output.mp4
lavfi
Libavfilter input virtual device.
This input device reads data from the open output pads of a libavfilter filtergraph.
For each filtergraph open output, the input device will create a corresponding stream
which is mapped to the generated output. The filtergraph is specified through the option
graph.
Options
graph
Specify the filtergraph to use as input. Each video open output must be labelled by a
unique string of the form "outN", where N is a number starting from 0 corresponding to
the mapped input stream generated by the device. The first unlabelled output is
automatically assigned to the "out0" label, but all the others need to be specified
explicitly.
The suffix "+subcc" can be appended to the output label to create an extra stream with
the closed captions packets attached to that output (experimental; only for EIA-608 /
CEA-708 for now). The subcc streams are created after all the normal streams, in the
order of the corresponding stream. For example, if there is "out19+subcc",
"out7+subcc" and up to "out42", the stream #43 is subcc for stream #7 and stream #44
is subcc for stream #19.
If not specified defaults to the filename specified for the input device.
graph_file
Set the filename of the filtergraph to be read and sent to the other filters. Syntax
of the filtergraph is the same as the one specified by the option graph.
dumpgraph
Dump graph to stderr.
Examples
• Create a color video stream and play it back with ffplay:
ffplay -f lavfi -graph "color=c=pink [out0]" dummy
• As the previous example, but use filename for specifying the graph description, and
omit the "out0" label:
ffplay -f lavfi color=c=pink
• Create three different video test filtered sources and play them:
ffplay -f lavfi -graph "testsrc [out0]; testsrc,hflip [out1]; testsrc,negate [out2]" test3
• Read an audio stream from a file using the amovie source and play it back with ffplay:
ffplay -f lavfi "amovie=test.wav"
• Read an audio stream and a video stream and play it back with ffplay:
ffplay -f lavfi "movie=test.avi[out0];amovie=test.wav[out1]"
• Dump decoded frames to images and Closed Captions to an RCWT backup:
ffmpeg -f lavfi -i "movie=test.ts[out0+subcc]" -map v frame%08d.png -map s -c copy -f rcwt subcc.bin
libcdio
Audio-CD input device based on libcdio.
To enable this input device during configuration you need libcdio installed on your
system. It requires the configure option "--enable-libcdio".
This device allows playing and grabbing from an Audio-CD.
For example to copy with ffmpeg the entire Audio-CD in /dev/sr0, you may run the command:
ffmpeg -f libcdio -i /dev/sr0 cd.wav
Options
speed
Set drive reading speed. Default value is 0.
The speed is specified CD-ROM speed units. The speed is set through the libcdio
"cdio_cddap_speed_set" function. On many CD-ROM drives, specifying a value too large
will result in using the fastest speed.
paranoia_mode
Set paranoia recovery mode flags. It accepts one of the following values:
disable
verify
overlap
neverskip
full
Default value is disable.
For more information about the available recovery modes, consult the paranoia project
documentation.
libdc1394
IIDC1394 input device, based on libdc1394 and libraw1394.
Requires the configure option "--enable-libdc1394".
Options
framerate
Set the frame rate. Default is "ntsc", corresponding to a frame rate of "30000/1001".
pixel_format
Select the pixel format. Default is "uyvy422".
video_size
Set the video size given as a string such as "640x480" or "hd720". Default is "qvga".
openal
The OpenAL input device provides audio capture on all systems with a working OpenAL 1.1
implementation.
To enable this input device during configuration, you need OpenAL headers and libraries
installed on your system, and need to configure FFmpeg with "--enable-openal".
OpenAL headers and libraries should be provided as part of your OpenAL implementation, or
as an additional download (an SDK). Depending on your installation you may need to specify
additional flags via the "--extra-cflags" and "--extra-ldflags" for allowing the build
system to locate the OpenAL headers and libraries.
An incomplete list of OpenAL implementations follows:
Creative
The official Windows implementation, providing hardware acceleration with supported
devices and software fallback. See <http://openal.org/>.
OpenAL Soft
Portable, open source (LGPL) software implementation. Includes backends for the most
common sound APIs on the Windows, Linux, Solaris, and BSD operating systems. See
<http://kcat.strangesoft.net/openal.html>.
Apple
OpenAL is part of Core Audio, the official Mac OS X Audio interface. See
<http://developer.apple.com/technologies/mac/audio-and-video.html>
This device allows one to capture from an audio input device handled through OpenAL.
You need to specify the name of the device to capture in the provided filename. If the
empty string is provided, the device will automatically select the default device. You can
get the list of the supported devices by using the option list_devices.
Options
channels
Set the number of channels in the captured audio. Only the values 1 (monaural) and 2
(stereo) are currently supported. Defaults to 2.
sample_size
Set the sample size (in bits) of the captured audio. Only the values 8 and 16 are
currently supported. Defaults to 16.
sample_rate
Set the sample rate (in Hz) of the captured audio. Defaults to 44.1k.
list_devices
If set to true, print a list of devices and exit. Defaults to false.
Examples
Print the list of OpenAL supported devices and exit:
$ ffmpeg -list_devices true -f openal -i dummy out.ogg
Capture from the OpenAL device DR-BT101 via PulseAudio:
$ ffmpeg -f openal -i 'DR-BT101 via PulseAudio' out.ogg
Capture from the default device (note the empty string '' as filename):
$ ffmpeg -f openal -i '' out.ogg
Capture from two devices simultaneously, writing to two different files, within the same
ffmpeg command:
$ ffmpeg -f openal -i 'DR-BT101 via PulseAudio' out1.ogg -f openal -i 'ALSA Default' out2.ogg
Note: not all OpenAL implementations support multiple simultaneous capture - try the
latest OpenAL Soft if the above does not work.
oss
Open Sound System input device.
The filename to provide to the input device is the device node representing the OSS input
device, and is usually set to /dev/dsp.
For example to grab from /dev/dsp using ffmpeg use the command:
ffmpeg -f oss -i /dev/dsp /tmp/oss.wav
For more information about OSS see: <http://manuals.opensound.com/usersguide/dsp.html>
Options
sample_rate
Set the sample rate in Hz. Default is 48000.
channels
Set the number of channels. Default is 2.
pulse
PulseAudio input device.
To enable this output device you need to configure FFmpeg with "--enable-libpulse".
The filename to provide to the input device is a source device or the string "default"
To list the PulseAudio source devices and their properties you can invoke the command
pactl list sources.
More information about PulseAudio can be found on <http://www.pulseaudio.org>.
Options
server
Connect to a specific PulseAudio server, specified by an IP address. Default server
is used when not provided.
name
Specify the application name PulseAudio will use when showing active clients, by
default it is the "LIBAVFORMAT_IDENT" string.
stream_name
Specify the stream name PulseAudio will use when showing active streams, by default it
is "record".
sample_rate
Specify the samplerate in Hz, by default 48kHz is used.
channels
Specify the channels in use, by default 2 (stereo) is set.
frame_size
This option does nothing and is deprecated.
fragment_size
Specify the size in bytes of the minimal buffering fragment in PulseAudio, it will
affect the audio latency. By default it is set to 50 ms amount of data.
wallclock
Set the initial PTS using the current time. Default is 1.
Examples
Record a stream from default device:
ffmpeg -f pulse -i default /tmp/pulse.wav
sndio
sndio input device.
To enable this input device during configuration you need libsndio installed on your
system.
The filename to provide to the input device is the device node representing the sndio
input device, and is usually set to /dev/audio0.
For example to grab from /dev/audio0 using ffmpeg use the command:
ffmpeg -f sndio -i /dev/audio0 /tmp/oss.wav
Options
sample_rate
Set the sample rate in Hz. Default is 48000.
channels
Set the number of channels. Default is 2.
video4linux2, v4l2
Video4Linux2 input video device.
"v4l2" can be used as alias for "video4linux2".
If FFmpeg is built with v4l-utils support (by using the "--enable-libv4l2" configure
option), it is possible to use it with the "-use_libv4l2" input device option.
The name of the device to grab is a file device node, usually Linux systems tend to
automatically create such nodes when the device (e.g. an USB webcam) is plugged into the
system, and has a name of the kind /dev/videoN, where N is a number associated to the
device.
Video4Linux2 devices usually support a limited set of widthxheight sizes and frame rates.
You can check which are supported using -list_formats all for Video4Linux2 devices. Some
devices, like TV cards, support one or more standards. It is possible to list all the
supported standards using -list_standards all.
The time base for the timestamps is 1 microsecond. Depending on the kernel version and
configuration, the timestamps may be derived from the real time clock (origin at the Unix
Epoch) or the monotonic clock (origin usually at boot time, unaffected by NTP or manual
changes to the clock). The -timestamps abs or -ts abs option can be used to force
conversion into the real time clock.
Some usage examples of the video4linux2 device with ffmpeg and ffplay:
• List supported formats for a video4linux2 device:
ffplay -f video4linux2 -list_formats all /dev/video0
• Grab and show the input of a video4linux2 device:
ffplay -f video4linux2 -framerate 30 -video_size hd720 /dev/video0
• Grab and record the input of a video4linux2 device, leave the frame rate and size as
previously set:
ffmpeg -f video4linux2 -input_format mjpeg -i /dev/video0 out.mpeg
For more information about Video4Linux, check <http://linuxtv.org/>.
Options
standard
Set the standard. Must be the name of a supported standard. To get a list of the
supported standards, use the list_standards option.
channel
Set the input channel number. Default to -1, which means using the previously selected
channel.
video_size
Set the video frame size. The argument must be a string in the form WIDTHxHEIGHT or a
valid size abbreviation.
pixel_format
Select the pixel format (only valid for raw video input).
input_format
Set the preferred pixel format (for raw video) or a codec name. This option allows
one to select the input format, when several are available.
framerate
Set the preferred video frame rate.
list_formats
List available formats (supported pixel formats, codecs, and frame sizes) and exit.
Available values are:
all Show all available (compressed and non-compressed) formats.
raw Show only raw video (non-compressed) formats.
compressed
Show only compressed formats.
list_standards
List supported standards and exit.
Available values are:
all Show all supported standards.
timestamps, ts
Set type of timestamps for grabbed frames.
Available values are:
default
Use timestamps from the kernel.
abs Use absolute timestamps (wall clock).
mono2abs
Force conversion from monotonic to absolute timestamps.
Default value is "default".
use_libv4l2
Use libv4l2 (v4l-utils) conversion functions. Default is 0.
vfwcap
VfW (Video for Windows) capture input device.
The filename passed as input is the capture driver number, ranging from 0 to 9. You may
use "list" as filename to print a list of drivers. Any other filename will be interpreted
as device number 0.
Options
video_size
Set the video frame size.
framerate
Set the grabbing frame rate. Default value is "ntsc", corresponding to a frame rate of
"30000/1001".
x11grab
X11 video input device.
To enable this input device during configuration you need libxcb installed on your system.
It will be automatically detected during configuration.
This device allows one to capture a region of an X11 display.
The filename passed as input has the syntax:
[<hostname>]:<display_number>.<screen_number>[+<x_offset>,<y_offset>]
hostname:display_number.screen_number specifies the X11 display name of the screen to grab
from. hostname can be omitted, and defaults to "localhost". The environment variable
DISPLAY contains the default display name.
x_offset and y_offset specify the offsets of the grabbed area with respect to the top-left
border of the X11 screen. They default to 0.
Check the X11 documentation (e.g. man X) for more detailed information.
Use the xdpyinfo program for getting basic information about the properties of your X11
display (e.g. grep for "name" or "dimensions").
For example to grab from :0.0 using ffmpeg:
ffmpeg -f x11grab -framerate 25 -video_size cif -i :0.0 out.mpg
Grab at position "10,20":
ffmpeg -f x11grab -framerate 25 -video_size cif -i :0.0+10,20 out.mpg
Options
select_region
Specify whether to select the grabbing area graphically using the pointer. A value of
1 prompts the user to select the grabbing area graphically by clicking and dragging. A
single click with no dragging will select the whole screen. A region with zero width
or height will also select the whole screen. This option overwrites the video_size,
grab_x, and grab_y options. Default value is 0.
draw_mouse
Specify whether to draw the mouse pointer. A value of 0 specifies not to draw the
pointer. Default value is 1.
follow_mouse
Make the grabbed area follow the mouse. The argument can be "centered" or a number of
pixels PIXELS.
When it is specified with "centered", the grabbing region follows the mouse pointer
and keeps the pointer at the center of region; otherwise, the region follows only when
the mouse pointer reaches within PIXELS (greater than zero) to the edge of region.
For example:
ffmpeg -f x11grab -follow_mouse centered -framerate 25 -video_size cif -i :0.0 out.mpg
To follow only when the mouse pointer reaches within 100 pixels to edge:
ffmpeg -f x11grab -follow_mouse 100 -framerate 25 -video_size cif -i :0.0 out.mpg
framerate
Set the grabbing frame rate. Default value is "ntsc", corresponding to a frame rate of
"30000/1001".
show_region
Show grabbed region on screen.
If show_region is specified with 1, then the grabbing region will be indicated on
screen. With this option, it is easy to know what is being grabbed if only a portion
of the screen is grabbed.
region_border
Set the region border thickness if -show_region 1 is used. Range is 1 to 128 and
default is 3 (XCB-based x11grab only).
For example:
ffmpeg -f x11grab -show_region 1 -framerate 25 -video_size cif -i :0.0+10,20 out.mpg
With follow_mouse:
ffmpeg -f x11grab -follow_mouse centered -show_region 1 -framerate 25 -video_size cif -i :0.0 out.mpg
window_id
Grab this window, instead of the whole screen. Default value is 0, which maps to the
whole screen (root window).
The id of a window can be found using the xwininfo program, possibly with options
-tree and -root.
If the window is later enlarged, the new area is not recorded. Video ends when the
window is closed, unmapped (i.e., iconified) or shrunk beyond the video size (which
defaults to the initial window size).
This option disables options follow_mouse and select_region.
video_size
Set the video frame size. Default is the full desktop or window.
grab_x
grab_y
Set the grabbing region coordinates. They are expressed as offset from the top left
corner of the X11 window and correspond to the x_offset and y_offset parameters in the
device name. The default value for both options is 0.
RESAMPLER OPTIONS
The audio resampler supports the following named options.
Options may be set by specifying -option value in the FFmpeg tools, option=value for the
aresample filter, by setting the value explicitly in the "SwrContext" options or using the
libavutil/opt.h API for programmatic use.
uchl, used_chlayout
Set used input channel layout. Default is unset. This option is only used for special
remapping.
isr, in_sample_rate
Set the input sample rate. Default value is 0.
osr, out_sample_rate
Set the output sample rate. Default value is 0.
isf, in_sample_fmt
Specify the input sample format. It is set by default to "none".
osf, out_sample_fmt
Specify the output sample format. It is set by default to "none".
tsf, internal_sample_fmt
Set the internal sample format. Default value is "none". This will automatically be
chosen when it is not explicitly set.
ichl, in_chlayout
ochl, out_chlayout
Set the input/output channel layout.
See the Channel Layout section in the ffmpeg-utils(1) manual for the required syntax.
clev, center_mix_level
Set the center mix level. It is a value expressed in deciBel, and must be in the
interval [-32,32].
slev, surround_mix_level
Set the surround mix level. It is a value expressed in deciBel, and must be in the
interval [-32,32].
lfe_mix_level
Set LFE mix into non LFE level. It is used when there is a LFE input but no LFE
output. It is a value expressed in deciBel, and must be in the interval [-32,32].
rmvol, rematrix_volume
Set rematrix volume. Default value is 1.0.
rematrix_maxval
Set maximum output value for rematrixing. This can be used to prevent clipping vs.
preventing volume reduction. A value of 1.0 prevents clipping.
flags, swr_flags
Set flags used by the converter. Default value is 0.
It supports the following individual flags:
res force resampling, this flag forces resampling to be used even when the input and
output sample rates match.
dither_scale
Set the dither scale. Default value is 1.
dither_method
Set dither method. Default value is 0.
Supported values:
rectangular
select rectangular dither
triangular
select triangular dither
triangular_hp
select triangular dither with high pass
lipshitz
select Lipshitz noise shaping dither.
shibata
select Shibata noise shaping dither.
low_shibata
select low Shibata noise shaping dither.
high_shibata
select high Shibata noise shaping dither.
f_weighted
select f-weighted noise shaping dither
modified_e_weighted
select modified-e-weighted noise shaping dither
improved_e_weighted
select improved-e-weighted noise shaping dither
resampler
Set resampling engine. Default value is swr.
Supported values:
swr select the native SW Resampler; filter options precision and cheby are not
applicable in this case.
soxr
select the SoX Resampler (where available); compensation, and filter options
filter_size, phase_shift, exact_rational, filter_type & kaiser_beta, are not
applicable in this case.
filter_size
For swr only, set resampling filter size, default value is 32.
phase_shift
For swr only, set resampling phase shift, default value is 10, and must be in the
interval [0,30].
linear_interp
Use linear interpolation when enabled (the default). Disable it if you want to
preserve speed instead of quality when exact_rational fails.
exact_rational
For swr only, when enabled, try to use exact phase_count based on input and output
sample rate. However, if it is larger than "1 << phase_shift", the phase_count will be
"1 << phase_shift" as fallback. Default is enabled.
cutoff
Set cutoff frequency (swr: 6dB point; soxr: 0dB point) ratio; must be a float value
between 0 and 1. Default value is 0.97 with swr, and 0.91 with soxr (which, with a
sample-rate of 44100, preserves the entire audio band to 20kHz).
precision
For soxr only, the precision in bits to which the resampled signal will be calculated.
The default value of 20 (which, with suitable dithering, is appropriate for a
destination bit-depth of 16) gives SoX's 'High Quality'; a value of 28 gives SoX's
'Very High Quality'.
cheby
For soxr only, selects passband rolloff none (Chebyshev) & higher-precision
approximation for 'irrational' ratios. Default value is 0.
async
For swr only, simple 1 parameter audio sync to timestamps using stretching, squeezing,
filling and trimming. Setting this to 1 will enable filling and trimming, larger
values represent the maximum amount in samples that the data may be stretched or
squeezed for each second. Default value is 0, thus no compensation is applied to make
the samples match the audio timestamps.
first_pts
For swr only, assume the first pts should be this value. The time unit is 1 / sample
rate. This allows for padding/trimming at the start of stream. By default, no
assumption is made about the first frame's expected pts, so no padding or trimming is
done. For example, this could be set to 0 to pad the beginning with silence if an
audio stream starts after the video stream or to trim any samples with a negative pts
due to encoder delay.
min_comp
For swr only, set the minimum difference between timestamps and audio data (in
seconds) to trigger stretching/squeezing/filling or trimming of the data to make it
match the timestamps. The default is that stretching/squeezing/filling and trimming is
disabled (min_comp = "FLT_MAX").
min_hard_comp
For swr only, set the minimum difference between timestamps and audio data (in
seconds) to trigger adding/dropping samples to make it match the timestamps. This
option effectively is a threshold to select between hard (trim/fill) and soft
(squeeze/stretch) compensation. Note that all compensation is by default disabled
through min_comp. The default is 0.1.
comp_duration
For swr only, set duration (in seconds) over which data is stretched/squeezed to make
it match the timestamps. Must be a non-negative double float value, default value is
1.0.
max_soft_comp
For swr only, set maximum factor by which data is stretched/squeezed to make it match
the timestamps. Must be a non-negative double float value, default value is 0.
matrix_encoding
Select matrixed stereo encoding.
It accepts the following values:
none
select none
dolby
select Dolby
dplii
select Dolby Pro Logic II
Default value is "none".
filter_type
For swr only, select resampling filter type. This only affects resampling operations.
It accepts the following values:
cubic
select cubic
blackman_nuttall
select Blackman Nuttall windowed sinc
kaiser
select Kaiser windowed sinc
kaiser_beta
For swr only, set Kaiser window beta value. Must be a double float value in the
interval [2,16], default value is 9.
output_sample_bits
For swr only, set number of used output sample bits for dithering. Must be an integer
in the interval [0,64], default value is 0, which means it's not used.
SCALER OPTIONS
The video scaler supports the following named options.
Options may be set by specifying -option value in the FFmpeg tools, with a few API-only
exceptions noted below. For programmatic use, they can be set explicitly in the
"SwsContext" options or through the libavutil/opt.h API.
sws_flags
Set the scaler flags. This is also used to set the scaling algorithm. Only a single
algorithm should be selected. Default value is bicubic.
It accepts the following values:
fast_bilinear
Select fast bilinear scaling algorithm.
bilinear
Select bilinear scaling algorithm.
bicubic
Select bicubic scaling algorithm.
experimental
Select experimental scaling algorithm.
neighbor
Select nearest neighbor rescaling algorithm.
area
Select averaging area rescaling algorithm.
bicublin
Select bicubic scaling algorithm for the luma component, bilinear for chroma
components.
gauss
Select Gaussian rescaling algorithm.
sinc
Select sinc rescaling algorithm.
lanczos
Select Lanczos rescaling algorithm. The default width (alpha) is 3 and can be
changed by setting "param0".
spline
Select natural bicubic spline rescaling algorithm.
print_info
Enable printing/debug logging.
accurate_rnd
Enable accurate rounding.
full_chroma_int
Enable full chroma interpolation.
full_chroma_inp
Select full chroma input.
bitexact
Enable bitexact output.
srcw (API only)
Set source width.
srch (API only)
Set source height.
dstw (API only)
Set destination width.
dsth (API only)
Set destination height.
src_format (API only)
Set source pixel format (must be expressed as an integer).
dst_format (API only)
Set destination pixel format (must be expressed as an integer).
src_range (boolean)
If value is set to 1, indicates source is full range. Default value is 0, which
indicates source is limited range.
dst_range (boolean)
If value is set to 1, enable full range for destination. Default value is 0, which
enables limited range.
param0, param1
Set scaling algorithm parameters. The specified values are specific of some scaling
algorithms and ignored by others. The specified values are floating point number
values.
sws_dither
Set the dithering algorithm. Accepts one of the following values. Default value is
auto.
auto
automatic choice
none
no dithering
bayer
bayer dither
ed error diffusion dither
a_dither
arithmetic dither, based using addition
x_dither
arithmetic dither, based using xor (more random/less apparent patterning that
a_dither).
alphablend
Set the alpha blending to use when the input has alpha but the output does not.
Default value is none.
uniform_color
Blend onto a uniform background color
checkerboard
Blend onto a checkerboard
none
No blending
FILTERING INTRODUCTION
Filtering in FFmpeg is enabled through the libavfilter library.
In libavfilter, a filter can have multiple inputs and multiple outputs. To illustrate the
sorts of things that are possible, we consider the following filtergraph.
[main]
input --> split ---------------------> overlay --> output
| ^
|[tmp] [flip]|
+-----> crop --> vflip -------+
This filtergraph splits the input stream in two streams, then sends one stream through the
crop filter and the vflip filter, before merging it back with the other stream by
overlaying it on top. You can use the following command to achieve this:
ffmpeg -i INPUT -vf "split [main][tmp]; [tmp] crop=iw:ih/2:0:0, vflip [flip]; [main][flip] overlay=0:H/2" OUTPUT
The result will be that the top half of the video is mirrored onto the bottom half of the
output video.
Filters in the same linear chain are separated by commas, and distinct linear chains of
filters are separated by semicolons. In our example, crop,vflip are in one linear chain,
split and overlay are separately in another. The points where the linear chains join are
labelled by names enclosed in square brackets. In the example, the split filter generates
two outputs that are associated to the labels [main] and [tmp].
The stream sent to the second output of split, labelled as [tmp], is processed through the
crop filter, which crops away the lower half part of the video, and then vertically
flipped. The overlay filter takes in input the first unchanged output of the split filter
(which was labelled as [main]), and overlay on its lower half the output generated by the
crop,vflip filterchain.
Some filters take in input a list of parameters: they are specified after the filter name
and an equal sign, and are separated from each other by a colon.
There exist so-called source filters that do not have an audio/video input, and sink
filters that will not have audio/video output.
GRAPH
The graph2dot program included in the FFmpeg tools directory can be used to parse a
filtergraph description and issue a corresponding textual representation in the dot
language.
Invoke the command:
graph2dot -h
to see how to use graph2dot.
You can then pass the dot description to the dot program (from the graphviz suite of
programs) and obtain a graphical representation of the filtergraph.
For example the sequence of commands:
echo <GRAPH_DESCRIPTION> | \
tools/graph2dot -o graph.tmp && \
dot -Tpng graph.tmp -o graph.png && \
display graph.png
can be used to create and display an image representing the graph described by the
GRAPH_DESCRIPTION string. Note that this string must be a complete self-contained graph,
with its inputs and outputs explicitly defined. For example if your command line is of
the form:
ffmpeg -i infile -vf scale=640:360 outfile
your GRAPH_DESCRIPTION string will need to be of the form:
nullsrc,scale=640:360,nullsink
you may also need to set the nullsrc parameters and add a format filter in order to
simulate a specific input file.
FILTERGRAPH DESCRIPTION
A filtergraph is a directed graph of connected filters. It can contain cycles, and there
can be multiple links between a pair of filters. Each link has one input pad on one side
connecting it to one filter from which it takes its input, and one output pad on the other
side connecting it to one filter accepting its output.
Each filter in a filtergraph is an instance of a filter class registered in the
application, which defines the features and the number of input and output pads of the
filter.
A filter with no input pads is called a "source", and a filter with no output pads is
called a "sink".
Filtergraph syntax
A filtergraph has a textual representation, which is recognized by the -filter/-vf/-af and
-filter_complex options in ffmpeg and -vf/-af in ffplay, and by the
avfilter_graph_parse_ptr() function defined in libavfilter/avfilter.h.
A filterchain consists of a sequence of connected filters, each one connected to the
previous one in the sequence. A filterchain is represented by a list of ","-separated
filter descriptions.
A filtergraph consists of a sequence of filterchains. A sequence of filterchains is
represented by a list of ";"-separated filterchain descriptions.
A filter is represented by a string of the form:
[in_link_1]...[in_link_N]filter_name@id=arguments[out_link_1]...[out_link_M]
filter_name is the name of the filter class of which the described filter is an instance
of, and has to be the name of one of the filter classes registered in the program
optionally followed by "@id". The name of the filter class is optionally followed by a
string "=arguments".
arguments is a string which contains the parameters used to initialize the filter
instance. It may have one of two forms:
• A ':'-separated list of key=value pairs.
• A ':'-separated list of value. In this case, the keys are assumed to be the option
names in the order they are declared. E.g. the "fade" filter declares three options in
this order -- type, start_frame and nb_frames. Then the parameter list in:0:30 means
that the value in is assigned to the option type, 0 to start_frame and 30 to
nb_frames.
• A ':'-separated list of mixed direct value and long key=value pairs. The direct value
must precede the key=value pairs, and follow the same constraints order of the
previous point. The following key=value pairs can be set in any preferred order.
If the option value itself is a list of items (e.g. the "format" filter takes a list of
pixel formats), the items in the list are usually separated by |.
The list of arguments can be quoted using the character ' as initial and ending mark, and
the character \ for escaping the characters within the quoted text; otherwise the argument
string is considered terminated when the next special character (belonging to the set
[]=;,) is encountered.
A special syntax implemented in the ffmpeg CLI tool allows loading option values from
files. This is done be prepending a slash '/' to the option name, then the supplied value
is interpreted as a path from which the actual value is loaded. E.g.
ffmpeg -i <INPUT> -vf drawtext=/text=/tmp/some_text <OUTPUT>
will load the text to be drawn from /tmp/some_text. API users wishing to implement a
similar feature should use the "avfilter_graph_segment_*()" functions together with custom
IO code.
The name and arguments of the filter are optionally preceded and followed by a list of
link labels. A link label allows one to name a link and associate it to a filter output
or input pad. The preceding labels in_link_1 ... in_link_N, are associated to the filter
input pads, the following labels out_link_1 ... out_link_M, are associated to the output
pads.
When two link labels with the same name are found in the filtergraph, a link between the
corresponding input and output pad is created.
If an output pad is not labelled, it is linked by default to the first unlabelled input
pad of the next filter in the filterchain. For example in the filterchain
nullsrc, split[L1], [L2]overlay, nullsink
the split filter instance has two output pads, and the overlay filter instance two input
pads. The first output pad of split is labelled "L1", the first input pad of overlay is
labelled "L2", and the second output pad of split is linked to the second input pad of
overlay, which are both unlabelled.
In a filter description, if the input label of the first filter is not specified, "in" is
assumed; if the output label of the last filter is not specified, "out" is assumed.
In a complete filterchain all the unlabelled filter input and output pads must be
connected. A filtergraph is considered valid if all the filter input and output pads of
all the filterchains are connected.
Leading and trailing whitespaces (space, tabs, or line feeds) separating tokens in the
filtergraph specification are ignored. This means that the filtergraph can be expressed
using empty lines and spaces to improve redability.
For example, the filtergraph:
testsrc,split[L1],hflip[L2];[L1][L2] hstack
can be represented as:
testsrc,
split [L1], hflip [L2];
[L1][L2] hstack
Libavfilter will automatically insert scale filters where format conversion is required.
It is possible to specify swscale flags for those automatically inserted scalers by
prepending "sws_flags=flags;" to the filtergraph description.
Here is a BNF description of the filtergraph syntax:
<NAME> ::= sequence of alphanumeric characters and '_'
<FILTER_NAME> ::= <NAME>["@"<NAME>]
<LINKLABEL> ::= "[" <NAME> "]"
<LINKLABELS> ::= <LINKLABEL> [<LINKLABELS>]
<FILTER_ARGUMENTS> ::= sequence of chars (possibly quoted)
<FILTER> ::= [<LINKLABELS>] <FILTER_NAME> ["=" <FILTER_ARGUMENTS>] [<LINKLABELS>]
<FILTERCHAIN> ::= <FILTER> [,<FILTERCHAIN>]
<FILTERGRAPH> ::= [sws_flags=<flags>;] <FILTERCHAIN> [;<FILTERGRAPH>]
Notes on filtergraph escaping
Filtergraph description composition entails several levels of escaping. See the "Quoting
and escaping" section in the ffmpeg-utils(1) manual for more information about the
employed escaping procedure.
A first level escaping affects the content of each filter option value, which may contain
the special character ":" used to separate values, or one of the escaping characters "\'".
A second level escaping affects the whole filter description, which may contain the
escaping characters "\'" or the special characters "[],;" used by the filtergraph
description.
Finally, when you specify a filtergraph on a shell commandline, you need to perform a
third level escaping for the shell special characters contained within it.
For example, consider the following string to be embedded in the drawtext filter
description text value:
this is a 'string': may contain one, or more, special characters
This string contains the "'" special escaping character, and the ":" special character, so
it needs to be escaped in this way:
text=this is a \'string\'\: may contain one, or more, special characters
A second level of escaping is required when embedding the filter description in a
filtergraph description, in order to escape all the filtergraph special characters. Thus
the example above becomes:
drawtext=text=this is a \\\'string\\\'\\: may contain one\, or more\, special characters
(note that in addition to the "\'" escaping special characters, also "," needs to be
escaped).
Finally an additional level of escaping is needed when writing the filtergraph description
in a shell command, which depends on the escaping rules of the adopted shell. For example,
assuming that "\" is special and needs to be escaped with another "\", the previous string
will finally result in:
-vf "drawtext=text=this is a \\\\\\'string\\\\\\'\\\\: may contain one\\, or more\\, special characters"
In order to avoid cumbersome escaping when using a commandline tool accepting a filter
specification as input, it is advisable to avoid direct inclusion of the filter or options
specification in the shell.
For example, in case of the drawtext filter, you might prefer to use the textfile option
in place of text to specify the text to render.
TIMELINE EDITING
Some filters support a generic enable option. For the filters supporting timeline editing,
this option can be set to an expression which is evaluated before sending a frame to the
filter. If the evaluation is non-zero, the filter will be enabled, otherwise the frame
will be sent unchanged to the next filter in the filtergraph.
The expression accepts the following values:
t timestamp expressed in seconds, NAN if the input timestamp is unknown
n sequential number of the input frame, starting from 0
pos the position in the file of the input frame, NAN if unknown; deprecated, do not use
w
h width and height of the input frame if video
Additionally, these filters support an enable command that can be used to re-define the
expression.
Like any other filtering option, the enable option follows the same rules.
For example, to enable a blur filter (smartblur) from 10 seconds to 3 minutes, and a
curves filter starting at 3 seconds:
smartblur = enable='between(t,10,3*60)',
curves = enable='gte(t,3)' : preset=cross_process
See "ffmpeg -filters" to view which filters have timeline support.
CHANGING OPTIONS AT RUNTIME WITH A COMMAND
Some options can be changed during the operation of the filter using a command. These
options are marked 'T' on the output of ffmpeg -h filter=<name of filter>. The name of
the command is the name of the option and the argument is the new value.
OPTIONS FOR FILTERS WITH SEVERAL INPUTS
Some filters with several inputs support a common set of options. These options can only
be set by name, not with the short notation.
eof_action
The action to take when EOF is encountered on the secondary input; it accepts one of
the following values:
repeat
Repeat the last frame (the default).
endall
End both streams.
pass
Pass the main input through.
shortest
If set to 1, force the output to terminate when the shortest input terminates. Default
value is 0.
repeatlast
If set to 1, force the filter to extend the last frame of secondary streams until the
end of the primary stream. A value of 0 disables this behavior. Default value is 1.
ts_sync_mode
How strictly to sync streams based on secondary input timestamps; it accepts one of
the following values:
default
Frame from secondary input with the nearest lower or equal timestamp to the
primary input frame.
nearest
Frame from secondary input with the absolute nearest timestamp to the primary
input frame.
AUDIO FILTERS
When you configure your FFmpeg build, you can disable any of the existing filters using
"--disable-filters". The configure output will show the audio filters included in your
build.
Below is a description of the currently available audio filters.
aap
Apply Affine Projection algorithm to the first audio stream using the second audio stream.
This adaptive filter is used to estimate unknown audio based on multiple input audio
samples. Affine projection algorithm can make trade-offs between computation complexity
with convergence speed.
A description of the accepted options follows.
order
Set the filter order.
projection
Set the projection order.
mu Set the filter mu.
delta
Set the coefficient to initialize internal covariance matrix.
out_mode
Set the filter output samples. It accepts the following values:
i Pass the 1st input.
d Pass the 2nd input.
o Pass difference between desired, 2nd input and error signal estimate.
n Pass difference between input, 1st input and error signal estimate.
e Pass error signal estimated samples.
Default value is o.
precision
Set which precision to use when processing samples.
auto
Auto pick internal sample format depending on other filters.
float
Always use single-floating point precision sample format.
double
Always use double-floating point precision sample format.
acompressor
A compressor is mainly used to reduce the dynamic range of a signal. Especially modern
music is mostly compressed at a high ratio to improve the overall loudness. It's done to
get the highest attention of a listener, "fatten" the sound and bring more "power" to the
track. If a signal is compressed too much it may sound dull or "dead" afterwards or it
may start to "pump" (which could be a powerful effect but can also destroy a track
completely). The right compression is the key to reach a professional sound and is the
high art of mixing and mastering. Because of its complex settings it may take a long time
to get the right feeling for this kind of effect.
Compression is done by detecting the volume above a chosen level "threshold" and dividing
it by the factor set with "ratio". So if you set the threshold to -12dB and your signal
reaches -6dB a ratio of 2:1 will result in a signal at -9dB. Because an exact manipulation
of the signal would cause distortion of the waveform the reduction can be levelled over
the time. This is done by setting "Attack" and "Release". "attack" determines how long
the signal has to rise above the threshold before any reduction will occur and "release"
sets the time the signal has to fall below the threshold to reduce the reduction again.
Shorter signals than the chosen attack time will be left untouched. The overall reduction
of the signal can be made up afterwards with the "makeup" setting. So compressing the
peaks of a signal about 6dB and raising the makeup to this level results in a signal twice
as loud than the source. To gain a softer entry in the compression the "knee" flattens the
hard edge at the threshold in the range of the chosen decibels.
The filter accepts the following options:
level_in
Set input gain. Default is 1. Range is between 0.015625 and 64.
mode
Set mode of compressor operation. Can be "upward" or "downward". Default is
"downward".
threshold
If a signal of stream rises above this level it will affect the gain reduction. By
default it is 0.125. Range is between 0.00097563 and 1.
ratio
Set a ratio by which the signal is reduced. 1:2 means that if the level rose 4dB above
the threshold, it will be only 2dB above after the reduction. Default is 2. Range is
between 1 and 20.
attack
Amount of milliseconds the signal has to rise above the threshold before gain
reduction starts. Default is 20. Range is between 0.01 and 2000.
release
Amount of milliseconds the signal has to fall below the threshold before reduction is
decreased again. Default is 250. Range is between 0.01 and 9000.
makeup
Set the amount by how much signal will be amplified after processing. Default is 1.
Range is from 1 to 64.
knee
Curve the sharp knee around the threshold to enter gain reduction more softly.
Default is 2.82843. Range is between 1 and 8.
link
Choose if the "average" level between all channels of input stream or the
louder("maximum") channel of input stream affects the reduction. Default is "average".
detection
Should the exact signal be taken in case of "peak" or an RMS one in case of "rms".
Default is "rms" which is mostly smoother.
mix How much to use compressed signal in output. Default is 1. Range is between 0 and 1.
Commands
This filter supports the all above options as commands.
acontrast
Simple audio dynamic range compression/expansion filter.
The filter accepts the following options:
contrast
Set contrast. Default is 33. Allowed range is between 0 and 100.
acopy
Copy the input audio source unchanged to the output. This is mainly useful for testing
purposes.
acrossfade
Apply cross fade from one input audio stream to another input audio stream. The cross
fade is applied for specified duration near the end of first stream.
The filter accepts the following options:
nb_samples, ns
Specify the number of samples for which the cross fade effect has to last. At the end
of the cross fade effect the first input audio will be completely silent. Default is
44100.
duration, d
Specify the duration of the cross fade effect. See the Time duration section in the
ffmpeg-utils(1) manual for the accepted syntax. By default the duration is determined
by nb_samples. If set this option is used instead of nb_samples.
overlap, o
Should first stream end overlap with second stream start. Default is enabled.
curve1
Set curve for cross fade transition for first stream.
curve2
Set curve for cross fade transition for second stream.
For description of available curve types see afade filter description.
Examples
• Cross fade from one input to another:
ffmpeg -i first.flac -i second.flac -filter_complex acrossfade=d=10:c1=exp:c2=exp output.flac
• Cross fade from one input to another but without overlapping:
ffmpeg -i first.flac -i second.flac -filter_complex acrossfade=d=10:o=0:c1=exp:c2=exp output.flac
acrossover
Split audio stream into several bands.
This filter splits audio stream into two or more frequency ranges. Summing all streams
back will give flat output.
The filter accepts the following options:
split
Set split frequencies. Those must be positive and increasing.
order
Set filter order for each band split. This controls filter roll-off or steepness of
filter transfer function. Available values are:
2nd 12 dB per octave.
4th 24 dB per octave.
6th 36 dB per octave.
8th 48 dB per octave.
10th
60 dB per octave.
12th
72 dB per octave.
14th
84 dB per octave.
16th
96 dB per octave.
18th
108 dB per octave.
20th
120 dB per octave.
Default is 4th.
level
Set input gain level. Allowed range is from 0 to 1. Default value is 1.
gains
Set output gain for each band. Default value is 1 for all bands.
precision
Set which precision to use when processing samples.
auto
Auto pick internal sample format depending on other filters.
float
Always use single-floating point precision sample format.
double
Always use double-floating point precision sample format.
Default value is "auto".
Examples
• Split input audio stream into two bands (low and high) with split frequency of 1500
Hz, each band will be in separate stream:
ffmpeg -i in.flac -filter_complex 'acrossover=split=1500[LOW][HIGH]' -map '[LOW]' low.wav -map '[HIGH]' high.wav
• Same as above, but with higher filter order:
ffmpeg -i in.flac -filter_complex 'acrossover=split=1500:order=8th[LOW][HIGH]' -map '[LOW]' low.wav -map '[HIGH]' high.wav
• Same as above, but also with additional middle band (frequencies between 1500 and
8000):
ffmpeg -i in.flac -filter_complex 'acrossover=split=1500 8000:order=8th[LOW][MID][HIGH]' -map '[LOW]' low.wav -map '[MID]' mid.wav -map '[HIGH]' high.wav
acrusher
Reduce audio bit resolution.
This filter is bit crusher with enhanced functionality. A bit crusher is used to audibly
reduce number of bits an audio signal is sampled with. This doesn't change the bit depth
at all, it just produces the effect. Material reduced in bit depth sounds more harsh and
"digital". This filter is able to even round to continuous values instead of discrete bit
depths. Additionally it has a D/C offset which results in different crushing of the lower
and the upper half of the signal. An Anti-Aliasing setting is able to produce "softer"
crushing sounds.
Another feature of this filter is the logarithmic mode. This setting switches from linear
distances between bits to logarithmic ones. The result is a much more "natural" sounding
crusher which doesn't gate low signals for example. The human ear has a logarithmic
perception, so this kind of crushing is much more pleasant. Logarithmic crushing is also
able to get anti-aliased.
The filter accepts the following options:
level_in
Set level in.
level_out
Set level out.
bits
Set bit reduction.
mix Set mixing amount.
mode
Can be linear: "lin" or logarithmic: "log".
dc Set DC.
aa Set anti-aliasing.
samples
Set sample reduction.
lfo Enable LFO. By default disabled.
lforange
Set LFO range.
lforate
Set LFO rate.
Commands
This filter supports the all above options as commands.
acue
Delay audio filtering until a given wallclock timestamp. See the cue filter.
adeclick
Remove impulsive noise from input audio.
Samples detected as impulsive noise are replaced by interpolated samples using
autoregressive modelling.
window, w
Set window size, in milliseconds. Allowed range is from 10 to 100. Default value is 55
milliseconds. This sets size of window which will be processed at once.
overlap, o
Set window overlap, in percentage of window size. Allowed range is from 50 to 95.
Default value is 75 percent. Setting this to a very high value increases impulsive
noise removal but makes whole process much slower.
arorder, a
Set autoregression order, in percentage of window size. Allowed range is from 0 to 25.
Default value is 2 percent. This option also controls quality of interpolated samples
using neighbour good samples.
threshold, t
Set threshold value. Allowed range is from 1 to 100. Default value is 2. This
controls the strength of impulsive noise which is going to be removed. The lower
value, the more samples will be detected as impulsive noise.
burst, b
Set burst fusion, in percentage of window size. Allowed range is 0 to 10. Default
value is 2. If any two samples detected as noise are spaced less than this value then
any sample between those two samples will be also detected as noise.
method, m
Set overlap method.
It accepts the following values:
add, a
Select overlap-add method. Even not interpolated samples are slightly changed with
this method.
save, s
Select overlap-save method. Not interpolated samples remain unchanged.
Default value is "a".
adeclip
Remove clipped samples from input audio.
Samples detected as clipped are replaced by interpolated samples using autoregressive
modelling.
window, w
Set window size, in milliseconds. Allowed range is from 10 to 100. Default value is
55 milliseconds. This sets size of window which will be processed at once.
overlap, o
Set window overlap, in percentage of window size. Allowed range is from 50 to 95.
Default value is 75 percent.
arorder, a
Set autoregression order, in percentage of window size. Allowed range is from 0 to 25.
Default value is 8 percent. This option also controls quality of interpolated samples
using neighbour good samples.
threshold, t
Set threshold value. Allowed range is from 1 to 100. Default value is 10. Higher
values make clip detection less aggressive.
hsize, n
Set size of histogram used to detect clips. Allowed range is from 100 to 9999.
Default value is 1000. Higher values make clip detection less aggressive.
method, m
Set overlap method.
It accepts the following values:
add, a
Select overlap-add method. Even not interpolated samples are slightly changed with
this method.
save, s
Select overlap-save method. Not interpolated samples remain unchanged.
Default value is "a".
adecorrelate
Apply decorrelation to input audio stream.
The filter accepts the following options:
stages
Set decorrelation stages of filtering. Allowed range is from 1 to 16. Default value is
6.
seed
Set random seed used for setting delay in samples across channels.
adelay
Delay one or more audio channels.
Samples in delayed channel are filled with silence.
The filter accepts the following option:
delays
Set list of delays in milliseconds for each channel separated by '|'. Unused delays
will be silently ignored. If number of given delays is smaller than number of channels
all remaining channels will not be delayed. If you want to delay exact number of
samples, append 'S' to number. If you want instead to delay in seconds, append 's' to
number.
all Use last set delay for all remaining channels. By default is disabled. This option if
enabled changes how option "delays" is interpreted.
Examples
• Delay first channel by 1.5 seconds, the third channel by 0.5 seconds and leave the
second channel (and any other channels that may be present) unchanged.
adelay=1500|0|500
• Delay second channel by 500 samples, the third channel by 700 samples and leave the
first channel (and any other channels that may be present) unchanged.
adelay=0|500S|700S
• Delay all channels by same number of samples:
adelay=delays=64S:all=1
adenorm
Remedy denormals in audio by adding extremely low-level noise.
This filter shall be placed before any filter that can produce denormals.
A description of the accepted parameters follows.
level
Set level of added noise in dB. Default is -351. Allowed range is from -451 to -90.
type
Set type of added noise.
dc Add DC signal.
ac Add AC signal.
square
Add square signal.
pulse
Add pulse signal.
Default is "dc".
Commands
This filter supports the all above options as commands.
aderivative, aintegral
Compute derivative/integral of audio stream.
Applying both filters one after another produces original audio.
adrc
Apply spectral dynamic range controller filter to input audio stream.
A description of the accepted options follows.
transfer
Set the transfer expression.
The expression can contain the following constants:
ch current channel number
sn current sample number
nb_channels
number of channels
t timestamp expressed in seconds
sr sample rate
p current frequency power value, in dB
f current frequency in Hz
Default value is "p".
attack
Set the attack in milliseconds. Default is 50 milliseconds. Allowed range is from 1
to 1000 milliseconds.
release
Set the release in milliseconds. Default is 100 milliseconds. Allowed range is from 5
to 2000 milliseconds.
channels
Set which channels to filter, by default "all" channels in audio stream are filtered.
Commands
This filter supports the all above options as commands.
Examples
• Apply spectral compression to all frequencies with threshold of -50 dB and 1:6 ratio:
adrc=transfer='if(gt(p,-50),-50+(p-(-50))/6,p)':attack=50:release=100
• Similar to above but with 1:2 ratio and filtering only front center channel:
adrc=transfer='if(gt(p,-50),-50+(p-(-50))/2,p)':attack=50:release=100:channels=FC
• Apply spectral noise gate to all frequencies with threshold of -85 dB and with short
attack time and short release time:
adrc=transfer='if(lte(p,-85),p-800,p)':attack=1:release=5
• Apply spectral expansion to all frequencies with threshold of -10 dB and 1:2 ratio:
adrc=transfer='if(lt(p,-10),-10+(p-(-10))*2,p)':attack=50:release=100
• Apply limiter to max -60 dB to all frequencies, with attack of 2 ms and release of 10
ms:
adrc=transfer='min(p,-60)':attack=2:release=10
adynamicequalizer
Apply dynamic equalization to input audio stream.
A description of the accepted options follows.
threshold
Set the detection threshold used to trigger equalization. Threshold detection is
using detection filter. Default value is 0. Allowed range is from 0 to 100.
dfrequency
Set the detection frequency in Hz used for detection filter used to trigger
equalization. Default value is 1000 Hz. Allowed range is between 2 and 1000000 Hz.
dqfactor
Set the detection resonance factor for detection filter used to trigger equalization.
Default value is 1. Allowed range is from 0.001 to 1000.
tfrequency
Set the target frequency of equalization filter. Default value is 1000 Hz. Allowed
range is between 2 and 1000000 Hz.
tqfactor
Set the target resonance factor for target equalization filter. Default value is 1.
Allowed range is from 0.001 to 1000.
attack
Set the amount of milliseconds the signal from detection has to rise above the
detection threshold before equalization starts. Default is 20. Allowed range is
between 1 and 2000.
release
Set the amount of milliseconds the signal from detection has to fall below the
detection threshold before equalization ends. Default is 200. Allowed range is
between 1 and 2000.
ratio
Set the ratio by which the equalization gain is raised. Default is 1. Allowed range
is between 0 and 30.
makeup
Set the makeup offset by which the equalization gain is raised. Default is 0. Allowed
range is between 0 and 100.
range
Set the max allowed cut/boost amount. Default is 50. Allowed range is from 1 to 200.
mode
Set the mode of filter operation, can be one of the following:
listen
Output only isolated detection signal.
cutbelow
Cut frequencies below detection threshold.
cutabove
Cut frequencies above detection threshold.
boostbelow
Boost frequencies below detection threshold.
boostabove
Boost frequencies above detection threshold.
Default mode is cutbelow.
dftype
Set the type of detection filter, can be one of the following:
bandpass
lowpass
highpass
peak
Default type is bandpass.
tftype
Set the type of target filter, can be one of the following:
bell
lowshelf
highshelf
Default type is bell.
auto
Automatically gather threshold from detection filter. By default is disabled. This
option is useful to detect threshold in certain time frame of input audio stream, in
such case option value is changed at runtime.
Available values are:
disabled
Disable using automatically gathered threshold value.
off Stop picking threshold value.
on Start picking threshold value.
adaptive
Adaptively pick threshold value, by calculating sliding window entropy.
precision
Set which precision to use when processing samples.
auto
Auto pick internal sample format depending on other filters.
float
Always use single-floating point precision sample format.
double
Always use double-floating point precision sample format.
Commands
This filter supports the all above options as commands.
adynamicsmooth
Apply dynamic smoothing to input audio stream.
A description of the accepted options follows.
sensitivity
Set an amount of sensitivity to frequency fluctations. Default is 2. Allowed range is
from 0 to 1e+06.
basefreq
Set a base frequency for smoothing. Default value is 22050. Allowed range is from 2
to 1e+06.
Commands
This filter supports the all above options as commands.
aecho
Apply echoing to the input audio.
Echoes are reflected sound and can occur naturally amongst mountains (and sometimes large
buildings) when talking or shouting; digital echo effects emulate this behaviour and are
often used to help fill out the sound of a single instrument or vocal. The time difference
between the original signal and the reflection is the "delay", and the loudness of the
reflected signal is the "decay". Multiple echoes can have different delays and decays.
A description of the accepted parameters follows.
in_gain
Set input gain of reflected signal. Default is 0.6.
out_gain
Set output gain of reflected signal. Default is 0.3.
delays
Set list of time intervals in milliseconds between original signal and reflections
separated by '|'. Allowed range for each "delay" is "(0 - 90000.0]". Default is 1000.
decays
Set list of loudness of reflected signals separated by '|'. Allowed range for each
"decay" is "(0 - 1.0]". Default is 0.5.
Examples
• Make it sound as if there are twice as many instruments as are actually playing:
aecho=0.8:0.88:60:0.4
• If delay is very short, then it sounds like a (metallic) robot playing music:
aecho=0.8:0.88:6:0.4
• A longer delay will sound like an open air concert in the mountains:
aecho=0.8:0.9:1000:0.3
• Same as above but with one more mountain:
aecho=0.8:0.9:1000|1800:0.3|0.25
aemphasis
Audio emphasis filter creates or restores material directly taken from LPs or emphased CDs
with different filter curves. E.g. to store music on vinyl the signal has to be altered by
a filter first to even out the disadvantages of this recording medium. Once the material
is played back the inverse filter has to be applied to restore the distortion of the
frequency response.
The filter accepts the following options:
level_in
Set input gain.
level_out
Set output gain.
mode
Set filter mode. For restoring material use "reproduction" mode, otherwise use
"production" mode. Default is "reproduction" mode.
type
Set filter type. Selects medium. Can be one of the following:
col select Columbia.
emi select EMI.
bsi select BSI (78RPM).
riaa
select RIAA.
cd select Compact Disc (CD).
50fm
select 50µs (FM).
75fm
select 75µs (FM).
50kf
select 50µs (FM-KF).
75kf
select 75µs (FM-KF).
Commands
This filter supports the all above options as commands.
aeval
Modify an audio signal according to the specified expressions.
This filter accepts one or more expressions (one for each channel), which are evaluated
and used to modify a corresponding audio signal.
It accepts the following parameters:
exprs
Set the '|'-separated expressions list for each separate channel. If the number of
input channels is greater than the number of expressions, the last specified
expression is used for the remaining output channels.
channel_layout, c
Set output channel layout. If not specified, the channel layout is specified by the
number of expressions. If set to same, it will use by default the same input channel
layout.
Each expression in exprs can contain the following constants and functions:
ch channel number of the current expression
n number of the evaluated sample, starting from 0
s sample rate
t time of the evaluated sample expressed in seconds
nb_in_channels
nb_out_channels
input and output number of channels
val(CH)
the value of input channel with number CH
Note: this filter is slow. For faster processing you should use a dedicated filter.
Examples
• Half volume:
aeval=val(ch)/2:c=same
• Invert phase of the second channel:
aeval=val(0)|-val(1)
aexciter
An exciter is used to produce high sound that is not present in the original signal. This
is done by creating harmonic distortions of the signal which are restricted in range and
added to the original signal. An Exciter raises the upper end of an audio signal without
simply raising the higher frequencies like an equalizer would do to create a more "crisp"
or "brilliant" sound.
The filter accepts the following options:
level_in
Set input level prior processing of signal. Allowed range is from 0 to 64. Default
value is 1.
level_out
Set output level after processing of signal. Allowed range is from 0 to 64. Default
value is 1.
amount
Set the amount of harmonics added to original signal. Allowed range is from 0 to 64.
Default value is 1.
drive
Set the amount of newly created harmonics. Allowed range is from 0.1 to 10. Default
value is 8.5.
blend
Set the octave of newly created harmonics. Allowed range is from -10 to 10. Default
value is 0.
freq
Set the lower frequency limit of producing harmonics in Hz. Allowed range is from
2000 to 12000 Hz. Default is 7500 Hz.
ceil
Set the upper frequency limit of producing harmonics. Allowed range is from 9999 to
20000 Hz. If value is lower than 10000 Hz no limit is applied.
listen
Mute the original signal and output only added harmonics. By default is disabled.
Commands
This filter supports the all above options as commands.
afade
Apply fade-in/out effect to input audio.
A description of the accepted parameters follows.
type, t
Specify the effect type, can be either "in" for fade-in, or "out" for a fade-out
effect. Default is "in".
start_sample, ss
Specify the number of the start sample for starting to apply the fade effect. Default
is 0.
nb_samples, ns
Specify the number of samples for which the fade effect has to last. At the end of the
fade-in effect the output audio will have the same volume as the input audio, at the
end of the fade-out transition the output audio will be silence. Default is 44100.
start_time, st
Specify the start time of the fade effect. Default is 0. The value must be specified
as a time duration; see the Time duration section in the ffmpeg-utils(1) manual for
the accepted syntax. If set this option is used instead of start_sample.
duration, d
Specify the duration of the fade effect. See the Time duration section in the
ffmpeg-utils(1) manual for the accepted syntax. At the end of the fade-in effect the
output audio will have the same volume as the input audio, at the end of the fade-out
transition the output audio will be silence. By default the duration is determined by
nb_samples. If set this option is used instead of nb_samples.
curve
Set curve for fade transition.
It accepts the following values:
tri select triangular, linear slope (default)
qsin
select quarter of sine wave
hsin
select half of sine wave
esin
select exponential sine wave
log select logarithmic
ipar
select inverted parabola
qua select quadratic
cub select cubic
squ select square root
cbr select cubic root
par select parabola
exp select exponential
iqsin
select inverted quarter of sine wave
ihsin
select inverted half of sine wave
dese
select double-exponential seat
desi
select double-exponential sigmoid
losi
select logistic sigmoid
sinc
select sine cardinal function
isinc
select inverted sine cardinal function
quat
select quartic
quatr
select quartic root
qsin2
select squared quarter of sine wave
hsin2
select squared half of sine wave
nofade
no fade applied
silence
Set the initial gain for fade-in or final gain for fade-out. Default value is 0.0.
unity
Set the initial gain for fade-out or final gain for fade-in. Default value is 1.0.
Commands
This filter supports the all above options as commands.
Examples
• Fade in first 15 seconds of audio:
afade=t=in:ss=0:d=15
• Fade out last 25 seconds of a 900 seconds audio:
afade=t=out:st=875:d=25
afftdn
Denoise audio samples with FFT.
A description of the accepted parameters follows.
noise_reduction, nr
Set the noise reduction in dB, allowed range is 0.01 to 97. Default value is 12 dB.
noise_floor, nf
Set the noise floor in dB, allowed range is -80 to -20. Default value is -50 dB.
noise_type, nt
Set the noise type.
It accepts the following values:
white, w
Select white noise.
vinyl, v
Select vinyl noise.
shellac, s
Select shellac noise.
custom, c
Select custom noise, defined in "bn" option.
Default value is white noise.
band_noise, bn
Set custom band noise profile for every one of 15 bands. Bands are separated by ' '
or '|'.
residual_floor, rf
Set the residual floor in dB, allowed range is -80 to -20. Default value is -38 dB.
track_noise, tn
Enable noise floor tracking. By default is disabled. With this enabled, noise floor
is automatically adjusted.
track_residual, tr
Enable residual tracking. By default is disabled.
output_mode, om
Set the output mode.
It accepts the following values:
input, i
Pass input unchanged.
output, o
Pass noise filtered out.
noise, n
Pass only noise.
Default value is output.
adaptivity, ad
Set the adaptivity factor, used how fast to adapt gains adjustments per each frequency
bin. Value 0 enables instant adaptation, while higher values react much slower.
Allowed range is from 0 to 1. Default value is 0.5.
floor_offset, fo
Set the noise floor offset factor. This option is used to adjust offset applied to
measured noise floor. It is only effective when noise floor tracking is enabled.
Allowed range is from -2.0 to 2.0. Default value is 1.0.
noise_link, nl
Set the noise link used for multichannel audio.
It accepts the following values:
none
Use unchanged channel's noise floor.
min Use measured min noise floor of all channels.
max Use measured max noise floor of all channels.
average
Use measured average noise floor of all channels.
Default value is min.
band_multiplier, bm
Set the band multiplier factor, used how much to spread bands across frequency bins.
Allowed range is from 0.2 to 5. Default value is 1.25.
sample_noise, sn
Toggle capturing and measurement of noise profile from input audio.
It accepts the following values:
start, begin
Start sample noise capture.
stop, end
Stop sample noise capture and measure new noise band profile.
Default value is "none".
gain_smooth, gs
Set gain smooth spatial radius, used to smooth gains applied to each frequency bin.
Useful to reduce random music noise artefacts. Higher values increases smoothing of
gains. Allowed range is from 0 to 50. Default value is 0.
Commands
This filter supports the some above mentioned options as commands.
Examples
• Reduce white noise by 10dB, and use previously measured noise floor of -40dB:
afftdn=nr=10:nf=-40
• Reduce white noise by 10dB, also set initial noise floor to -80dB and enable automatic
tracking of noise floor so noise floor will gradually change during processing:
afftdn=nr=10:nf=-80:tn=1
• Reduce noise by 20dB, using noise floor of -40dB and using commands to take noise
profile of first 0.4 seconds of input audio:
asendcmd=0.0 afftdn sn start,asendcmd=0.4 afftdn sn stop,afftdn=nr=20:nf=-40
afftfilt
Apply arbitrary expressions to samples in frequency domain.
real
Set frequency domain real expression for each separate channel separated by '|'.
Default is "re". If the number of input channels is greater than the number of
expressions, the last specified expression is used for the remaining output channels.
imag
Set frequency domain imaginary expression for each separate channel separated by '|'.
Default is "im".
Each expression in real and imag can contain the following constants and functions:
sr sample rate
b current frequency bin number
nb number of available bins
ch channel number of the current expression
chs number of channels
pts current frame pts
re current real part of frequency bin of current channel
im current imaginary part of frequency bin of current channel
real(b, ch)
Return the value of real part of frequency bin at location (bin,channel)
imag(b, ch)
Return the value of imaginary part of frequency bin at location (bin,channel)
win_size
Set window size. Allowed range is from 16 to 131072. Default is 4096
win_func
Set window function.
It accepts the following values:
rect
bartlett
hann, hanning
hamming
blackman
welch
flattop
bharris
bnuttall
bhann
sine
nuttall
lanczos
gauss
tukey
dolph
cauchy
parzen
poisson
bohman
kaiser
Default is "hann".
overlap
Set window overlap. If set to 1, the recommended overlap for selected window function
will be picked. Default is 0.75.
Examples
• Leave almost only low frequencies in audio:
afftfilt="'real=re * (1-clip((b/nb)*b,0,1))':imag='im * (1-clip((b/nb)*b,0,1))'"
• Apply robotize effect:
afftfilt="real='hypot(re,im)*sin(0)':imag='hypot(re,im)*cos(0)':win_size=512:overlap=0.75"
• Apply whisper effect:
afftfilt="real='hypot(re,im)*cos((random(0)*2-1)*2*3.14)':imag='hypot(re,im)*sin((random(1)*2-1)*2*3.14)':win_size=128:overlap=0.8"
• Apply phase shift:
afftfilt="real=re*cos(1)-im*sin(1):imag=re*sin(1)+im*cos(1)"
afir
Apply an arbitrary Finite Impulse Response filter.
This filter is designed for applying long FIR filters, up to 60 seconds long.
It can be used as component for digital crossover filters, room equalization, cross talk
cancellation, wavefield synthesis, auralization, ambiophonics, ambisonics and
spatialization.
This filter uses the streams higher than first one as FIR coefficients. If the non-first
stream holds a single channel, it will be used for all input channels in the first stream,
otherwise the number of channels in the non-first stream must be same as the number of
channels in the first stream.
It accepts the following parameters:
dry Set dry gain. This sets input gain.
wet Set wet gain. This sets final output gain.
length
Set Impulse Response filter length. Default is 1, which means whole IR is processed.
gtype
This option is deprecated, and does nothing.
irnorm
Set norm to be applied to IR coefficients before filtering. Allowed range is from -1
to 2. IR coefficients are normalized with calculated vector norm set by this option.
For negative values, no norm is calculated, and IR coefficients are not modified at
all. Default is 1.
irlink
For multichannel IR if this option is set to true, all IR channels will be normalized
with maximal measured gain of all IR channels coefficients as set by "irnorm" option.
When disabled, all IR coefficients in each IR channel will be normalized
independently. Default is true.
irgain
Set gain to be applied to IR coefficients before filtering. Allowed range is 0 to 1.
This gain is applied after any gain applied with irnorm option.
irfmt
Set format of IR stream. Can be "mono" or "input". Default is "input".
maxir
Set max allowed Impulse Response filter duration in seconds. Default is 30 seconds.
Allowed range is 0.1 to 60 seconds.
response
This option is deprecated, and does nothing.
channel
This option is deprecated, and does nothing.
size
This option is deprecated, and does nothing.
rate
This option is deprecated, and does nothing.
minp
Set minimal partition size used for convolution. Default is 8192. Allowed range is
from 1 to 65536. Lower values decreases latency at cost of higher CPU usage.
maxp
Set maximal partition size used for convolution. Default is 8192. Allowed range is
from 8 to 65536. Lower values may increase CPU usage.
nbirs
Set number of input impulse responses streams which will be switchable at runtime.
Allowed range is from 1 to 32. Default is 1.
ir Set IR stream which will be used for convolution, starting from 0, should always be
lower than supplied value by "nbirs" option. Default is 0. This option can be changed
at runtime via commands.
precision
Set which precision to use when processing samples.
auto
Auto pick internal sample format depending on other filters.
float
Always use single-floating point precision sample format.
double
Always use double-floating point precision sample format.
Default value is auto.
irload
Set when to load IR stream. Can be "init" or "access". First one load and prepares
all IRs on initialization, second one once on first access of specific IR. Default is
"init".
Examples
• Apply reverb to stream using mono IR file as second input, complete command using
ffmpeg:
ffmpeg -i input.wav -i middle_tunnel_1way_mono.wav -lavfi afir output.wav
• Apply true stereo processing given input stereo stream, and two stereo impulse
responses for left and right channel, the impulse response files are files with names
l_ir.wav and r_ir.wav, and setting irnorm option value:
"pan=4C|c0=FL|c1=FL|c2=FR|c3=FR[a];amovie=l_ir.wav[LIR];amovie=r_ir.wav[RIR];[LIR][RIR]amerge[ir];[a][ir]afir=irfmt=input:irnorm=1.2,pan=stereo|FL<c0+c2|FR<c1+c3"
• Similar to above example, but with "irgain" explicitly set to estimated value and with
"irnorm" disabled:
"pan=4C|c0=FL|c1=FL|c2=FR|c3=FR[a];amovie=l_ir.wav[LIR];amovie=r_ir.wav[RIR];[LIR][RIR]amerge[ir];[a][ir]afir=irfmt=input:irgain=-5dB:irnom=-1,pan=stereo|FL<c0+c2|FR<c1+c3"
aformat
Set output format constraints for the input audio. The framework will negotiate the most
appropriate format to minimize conversions.
It accepts the following parameters:
sample_fmts, f
A '|'-separated list of requested sample formats.
sample_rates, r
A '|'-separated list of requested sample rates.
channel_layouts, cl
A '|'-separated list of requested channel layouts.
See the Channel Layout section in the ffmpeg-utils(1) manual for the required syntax.
If a parameter is omitted, all values are allowed.
Force the output to either unsigned 8-bit or signed 16-bit stereo
aformat=sample_fmts=u8|s16:channel_layouts=stereo
afreqshift
Apply frequency shift to input audio samples.
The filter accepts the following options:
shift
Specify frequency shift. Allowed range is -INT_MAX to INT_MAX. Default value is 0.0.
level
Set output gain applied to final output. Allowed range is from 0.0 to 1.0. Default
value is 1.0.
order
Set filter order used for filtering. Allowed range is from 1 to 16. Default value is
8.
Commands
This filter supports the all above options as commands.
afwtdn
Reduce broadband noise from input samples using Wavelets.
A description of the accepted options follows.
sigma
Set the noise sigma, allowed range is from 0 to 1. Default value is 0. This option
controls strength of denoising applied to input samples. Most useful way to set this
option is via decibels, eg. -45dB.
levels
Set the number of wavelet levels of decomposition. Allowed range is from 1 to 12.
Default value is 10. Setting this too low make denoising performance very poor.
wavet
Set wavelet type for decomposition of input frame. They are sorted by number of
coefficients, from lowest to highest. More coefficients means worse filtering speed,
but overall better quality. Available wavelets are:
sym2
sym4
rbior68
deb10
sym10
coif5
bl3
percent
Set percent of full denoising. Allowed range is from 0 to 100 percent. Default value
is 85 percent or partial denoising.
profile
If enabled, first input frame will be used as noise profile. If first frame samples
contain non-noise performance will be very poor.
adaptive
If enabled, input frames are analyzed for presence of noise. If noise is detected
with high possibility then input frame profile will be used for processing following
frames, until new noise frame is detected.
samples
Set size of single frame in number of samples. Allowed range is from 512 to 65536.
Default frame size is 8192 samples.
softness
Set softness applied inside thresholding function. Allowed range is from 0 to 10.
Default softness is 1.
Commands
This filter supports the all above options as commands.
agate
A gate is mainly used to reduce lower parts of a signal. This kind of signal processing
reduces disturbing noise between useful signals.
Gating is done by detecting the volume below a chosen level threshold and dividing it by
the factor set with ratio. The bottom of the noise floor is set via range. Because an
exact manipulation of the signal would cause distortion of the waveform the reduction can
be levelled over time. This is done by setting attack and release.
attack determines how long the signal has to fall below the threshold before any reduction
will occur and release sets the time the signal has to rise above the threshold to reduce
the reduction again. Shorter signals than the chosen attack time will be left untouched.
level_in
Set input level before filtering. Default is 1. Allowed range is from 0.015625 to 64.
mode
Set the mode of operation. Can be "upward" or "downward". Default is "downward". If
set to "upward" mode, higher parts of signal will be amplified, expanding dynamic
range in upward direction. Otherwise, in case of "downward" lower parts of signal
will be reduced.
range
Set the level of gain reduction when the signal is below the threshold. Default is
0.06125. Allowed range is from 0 to 1. Setting this to 0 disables reduction and then
filter behaves like expander.
threshold
If a signal rises above this level the gain reduction is released. Default is 0.125.
Allowed range is from 0 to 1.
ratio
Set a ratio by which the signal is reduced. Default is 2. Allowed range is from 1 to
9000.
attack
Amount of milliseconds the signal has to rise above the threshold before gain
reduction stops. Default is 20 milliseconds. Allowed range is from 0.01 to 9000.
release
Amount of milliseconds the signal has to fall below the threshold before the reduction
is increased again. Default is 250 milliseconds. Allowed range is from 0.01 to 9000.
makeup
Set amount of amplification of signal after processing. Default is 1. Allowed range
is from 1 to 64.
knee
Curve the sharp knee around the threshold to enter gain reduction more softly.
Default is 2.828427125. Allowed range is from 1 to 8.
detection
Choose if exact signal should be taken for detection or an RMS like one. Default is
"rms". Can be "peak" or "rms".
link
Choose if the average level between all channels or the louder channel affects the
reduction. Default is "average". Can be "average" or "maximum".
Commands
This filter supports the all above options as commands.
aiir
Apply an arbitrary Infinite Impulse Response filter.
It accepts the following parameters:
zeros, z
Set B/numerator/zeros/reflection coefficients.
poles, p
Set A/denominator/poles/ladder coefficients.
gains, k
Set channels gains.
dry_gain
Set input gain.
wet_gain
Set output gain.
format, f
Set coefficients format.
ll lattice-ladder function
sf analog transfer function
tf digital transfer function
zp Z-plane zeros/poles, cartesian (default)
pr Z-plane zeros/poles, polar radians
pd Z-plane zeros/poles, polar degrees
sp S-plane zeros/poles
process, r
Set type of processing.
d direct processing
s serial processing
p parallel processing
precision, e
Set filtering precision.
dbl double-precision floating-point (default)
flt single-precision floating-point
i32 32-bit integers
i16 16-bit integers
normalize, n
Normalize filter coefficients, by default is enabled. Enabling it will normalize
magnitude response at DC to 0dB.
mix How much to use filtered signal in output. Default is 1. Range is between 0 and 1.
response
Show IR frequency response, magnitude(magenta), phase(green) and group delay(yellow)
in additional video stream. By default it is disabled.
channel
Set for which IR channel to display frequency response. By default is first channel
displayed. This option is used only when response is enabled.
size
Set video stream size. This option is used only when response is enabled.
Coefficients in "tf" and "sf" format are separated by spaces and are in ascending order.
Coefficients in "zp" format are separated by spaces and order of coefficients doesn't
matter. Coefficients in "zp" format are complex numbers with i imaginary unit.
Different coefficients and gains can be provided for every channel, in such case use '|'
to separate coefficients or gains. Last provided coefficients will be used for all
remaining channels.
Examples
• Apply 2 pole elliptic notch at around 5000Hz for 48000 Hz sample rate:
aiir=k=1:z=7.957584807809675810E-1 -2.575128568908332300 3.674839853930788710 -2.57512875289799137 7.957586296317130880E-1:p=1 -2.86950072432325953 3.63022088054647218 -2.28075678147272232 6.361362326477423500E-1:f=tf:r=d
• Same as above but in "zp" format:
aiir=k=0.79575848078096756:z=0.80918701+0.58773007i 0.80918701-0.58773007i 0.80884700+0.58784055i 0.80884700-0.58784055i:p=0.63892345+0.59951235i 0.63892345-0.59951235i 0.79582691+0.44198673i 0.79582691-0.44198673i:f=zp:r=s
• Apply 3-rd order analog normalized Butterworth low-pass filter, using analog transfer
function format:
aiir=z=1.3057 0 0 0:p=1.3057 2.3892 2.1860 1:f=sf:r=d
alimiter
The limiter prevents an input signal from rising over a desired threshold. This limiter
uses lookahead technology to prevent your signal from distorting. It means that there is
a small delay after the signal is processed. Keep in mind that the delay it produces is
the attack time you set.
The filter accepts the following options:
level_in
Set input gain. Default is 1.
level_out
Set output gain. Default is 1.
limit
Don't let signals above this level pass the limiter. Default is 1.
attack
The limiter will reach its attenuation level in this amount of time in milliseconds.
Default is 5 milliseconds.
release
Come back from limiting to attenuation 1.0 in this amount of milliseconds. Default is
50 milliseconds.
asc When gain reduction is always needed ASC takes care of releasing to an average
reduction level rather than reaching a reduction of 0 in the release time.
asc_level
Select how much the release time is affected by ASC, 0 means nearly no changes in
release time while 1 produces higher release times.
level
Auto level output signal. Default is enabled. This normalizes audio back to 0dB if
enabled.
latency
Compensate the delay introduced by using the lookahead buffer set with attack
parameter. Also flush the valid audio data in the lookahead buffer when the stream
hits EOF.
Depending on picked setting it is recommended to upsample input 2x or 4x times with
aresample before applying this filter.
allpass
Apply a two-pole all-pass filter with central frequency (in Hz) frequency, and filter-
width width. An all-pass filter changes the audio's frequency to phase relationship
without changing its frequency to amplitude relationship.
The filter accepts the following options:
frequency, f
Set frequency in Hz.
width_type, t
Set method to specify band-width of filter.
h Hz
q Q-Factor
o octave
s slope
k kHz
width, w
Specify the band-width of a filter in width_type units.
mix, m
How much to use filtered signal in output. Default is 1. Range is between 0 and 1.
channels, c
Specify which channels to filter, by default all available are filtered.
normalize, n
Normalize biquad coefficients, by default is disabled. Enabling it will normalize
magnitude response at DC to 0dB.
order, o
Set the filter order, can be 1 or 2. Default is 2.
transform, a
Set transform type of IIR filter.
di
dii
tdi
tdii
latt
svf
zdf
precision, r
Set precision of filtering.
auto
Pick automatic sample format depending on surround filters.
s16 Always use signed 16-bit.
s32 Always use signed 32-bit.
f32 Always use float 32-bit.
f64 Always use float 64-bit.
Commands
This filter supports the following commands:
frequency, f
Change allpass frequency. Syntax for the command is : "frequency"
width_type, t
Change allpass width_type. Syntax for the command is : "width_type"
width, w
Change allpass width. Syntax for the command is : "width"
mix, m
Change allpass mix. Syntax for the command is : "mix"
aloop
Loop audio samples.
The filter accepts the following options:
loop
Set the number of loops. Setting this value to -1 will result in infinite loops.
Default is 0.
size
Set maximal number of samples. Default is 0.
start
Set first sample of loop. Default is 0.
time
Set the time of loop start in seconds. Only used if option named start is set to -1.
amerge
Merge two or more audio streams into a single multi-channel stream.
The filter accepts the following options:
inputs
Set the number of inputs. Default is 2.
If the channel layouts of the inputs are disjoint, and therefore compatible, the channel
layout of the output will be set accordingly and the channels will be reordered as
necessary. If the channel layouts of the inputs are not disjoint, the output will have all
the channels of the first input then all the channels of the second input, in that order,
and the channel layout of the output will be the default value corresponding to the total
number of channels.
For example, if the first input is in 2.1 (FL+FR+LF) and the second input is FC+BL+BR,
then the output will be in 5.1, with the channels in the following order: a1, a2, b1, a3,
b2, b3 (a1 is the first channel of the first input, b1 is the first channel of the second
input).
On the other hand, if both input are in stereo, the output channels will be in the default
order: a1, a2, b1, b2, and the channel layout will be arbitrarily set to 4.0, which may or
may not be the expected value.
All inputs must have the same sample rate, and format.
If inputs do not have the same duration, the output will stop with the shortest.
Examples
• Merge two mono files into a stereo stream:
amovie=left.wav [l] ; amovie=right.mp3 [r] ; [l] [r] amerge
• Multiple merges assuming 1 video stream and 6 audio streams in input.mkv:
ffmpeg -i input.mkv -filter_complex "[0:1][0:2][0:3][0:4][0:5][0:6] amerge=inputs=6" -c:a pcm_s16le output.mkv
amix
Mixes multiple audio inputs into a single output.
Note that this filter only supports float samples (the amerge and pan audio filters
support many formats). If the amix input has integer samples then aresample will be
automatically inserted to perform the conversion to float samples.
It accepts the following parameters:
inputs
The number of inputs. If unspecified, it defaults to 2.
duration
How to determine the end-of-stream.
longest
The duration of the longest input. (default)
shortest
The duration of the shortest input.
first
The duration of the first input.
dropout_transition
The transition time, in seconds, for volume renormalization when an input stream ends.
The default value is 2 seconds.
weights
Specify weight of each input audio stream as a sequence of numbers separated by a
space. If fewer weights are specified compared to number of inputs, the last weight is
assigned to the remaining inputs. Default weight for each input is 1.
normalize
Always scale inputs instead of only doing summation of samples. Beware of heavy
clipping if inputs are not normalized prior or after filtering by this filter if this
option is disabled. By default is enabled.
Examples
• This will mix 3 input audio streams to a single output with the same duration as the
first input and a dropout transition time of 3 seconds:
ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex amix=inputs=3:duration=first:dropout_transition=3 OUTPUT
• This will mix one vocal and one music input audio stream to a single output with the
same duration as the longest input. The music will have quarter the weight as the
vocals, and the inputs are not normalized:
ffmpeg -i VOCALS -i MUSIC -filter_complex amix=inputs=2:duration=longest:dropout_transition=0:weights="1 0.25":normalize=0 OUTPUT
Commands
This filter supports the following commands:
weights
normalize
Syntax is same as option with same name.
amultiply
Multiply first audio stream with second audio stream and store result in output audio
stream. Multiplication is done by multiplying each sample from first stream with sample at
same position from second stream.
With this element-wise multiplication one can create amplitude fades and amplitude
modulations.
anequalizer
High-order parametric multiband equalizer for each channel.
It accepts the following parameters:
params
This option string is in format: "cchn f=cf w=w g=g t=f | ..." Each equalizer band is
separated by '|'.
chn Set channel number to which equalization will be applied. If input doesn't have
that channel the entry is ignored.
f Set central frequency for band. If input doesn't have that frequency the entry is
ignored.
w Set band width in Hertz.
g Set band gain in dB.
t Set filter type for band, optional, can be:
0 Butterworth, this is default.
1 Chebyshev type 1.
2 Chebyshev type 2.
curves
With this option activated frequency response of anequalizer is displayed in video
stream.
size
Set video stream size. Only useful if curves option is activated.
mgain
Set max gain that will be displayed. Only useful if curves option is activated.
Setting this to a reasonable value makes it possible to display gain which is derived
from neighbour bands which are too close to each other and thus produce higher gain
when both are activated.
fscale
Set frequency scale used to draw frequency response in video output. Can be linear or
logarithmic. Default is logarithmic.
colors
Set color for each channel curve which is going to be displayed in video stream. This
is list of color names separated by space or by '|'. Unrecognised or missing colors
will be replaced by white color.
Examples
• Lower gain by 10 of central frequency 200Hz and width 100 Hz for first 2 channels
using Chebyshev type 1 filter:
anequalizer=c0 f=200 w=100 g=-10 t=1|c1 f=200 w=100 g=-10 t=1
Commands
This filter supports the following commands:
change
Alter existing filter parameters. Syntax for the commands is :
"fN|f=freq|w=width|g=gain"
fN is existing filter number, starting from 0, if no such filter is available error is
returned. freq set new frequency parameter. width set new width parameter in Hertz.
gain set new gain parameter in dB.
Full filter invocation with asendcmd may look like this: asendcmd=c='4.0 anequalizer
change 0|f=200|w=50|g=1',anequalizer=...
anlmdn
Reduce broadband noise in audio samples using Non-Local Means algorithm.
Each sample is adjusted by looking for other samples with similar contexts. This context
similarity is defined by comparing their surrounding patches of size p. Patches are
searched in an area of r around the sample.
The filter accepts the following options:
strength, s
Set denoising strength. Allowed range is from 0.00001 to 10000. Default value is
0.00001.
patch, p
Set patch radius duration. Allowed range is from 1 to 100 milliseconds. Default value
is 2 milliseconds.
research, r
Set research radius duration. Allowed range is from 2 to 300 milliseconds. Default
value is 6 milliseconds.
output, o
Set the output mode.
It accepts the following values:
i Pass input unchanged.
o Pass noise filtered out.
n Pass only noise.
Default value is o.
smooth, m
Set smooth factor. Default value is 11. Allowed range is from 1 to 1000.
Commands
This filter supports the all above options as commands.
anlmf, anlms
Apply Normalized Least-Mean-(Squares|Fourth) algorithm to the first audio stream using the
second audio stream.
This adaptive filter is used to mimic a desired filter by finding the filter coefficients
that relate to producing the least mean square of the error signal (difference between the
desired, 2nd input audio stream and the actual signal, the 1st input audio stream).
A description of the accepted options follows.
order
Set filter order.
mu Set filter mu.
eps Set the filter eps.
leakage
Set the filter leakage.
out_mode
It accepts the following values:
i Pass the 1st input.
d Pass the 2nd input.
o Pass difference between desired, 2nd input and error signal estimate.
n Pass difference between input, 1st input and error signal estimate.
e Pass error signal estimated samples.
Default value is o.
precision
Set which precision to use when processing samples.
auto
Auto pick internal sample format depending on other filters.
float
Always use single-floating point precision sample format.
double
Always use double-floating point precision sample format.
Examples
• One of many usages of this filter is noise reduction, input audio is filtered with
same samples that are delayed by fixed amount, one such example for stereo audio is:
asplit[a][b],[a]adelay=32S|32S[a],[b][a]anlms=order=128:leakage=0.0005:mu=.5:out_mode=o
Commands
This filter supports the same commands as options, excluding option "order".
anull
Pass the audio source unchanged to the output.
apad
Pad the end of an audio stream with silence.
This can be used together with ffmpeg -shortest to extend audio streams to the same length
as the video stream.
A description of the accepted options follows.
packet_size
Set silence packet size. Default value is 4096.
pad_len
Set the number of samples of silence to add to the end. After the value is reached,
the stream is terminated. This option is mutually exclusive with whole_len.
whole_len
Set the minimum total number of samples in the output audio stream. If the value is
longer than the input audio length, silence is added to the end, until the value is
reached. This option is mutually exclusive with pad_len.
pad_dur
Specify the duration of samples of silence to add. See the Time duration section in
the ffmpeg-utils(1) manual for the accepted syntax. Used only if set to non-negative
value.
whole_dur
Specify the minimum total duration in the output audio stream. See the Time duration
section in the ffmpeg-utils(1) manual for the accepted syntax. Used only if set to
non-negative value. If the value is longer than the input audio length, silence is
added to the end, until the value is reached. This option is mutually exclusive with
pad_dur
If neither the pad_len nor the whole_len nor pad_dur nor whole_dur option is set, the
filter will add silence to the end of the input stream indefinitely.
Note that for ffmpeg 4.4 and earlier a zero pad_dur or whole_dur also caused the filter to
add silence indefinitely.
Examples
• Add 1024 samples of silence to the end of the input:
apad=pad_len=1024
• Make sure the audio output will contain at least 10000 samples, pad the input with
silence if required:
apad=whole_len=10000
• Use ffmpeg to pad the audio input with silence, so that the video stream will always
result the shortest and will be converted until the end in the output file when using
the shortest option:
ffmpeg -i VIDEO -i AUDIO -filter_complex "[1:0]apad" -shortest OUTPUT
aphaser
Add a phasing effect to the input audio.
A phaser filter creates series of peaks and troughs in the frequency spectrum. The
position of the peaks and troughs are modulated so that they vary over time, creating a
sweeping effect.
A description of the accepted parameters follows.
in_gain
Set input gain. Default is 0.4.
out_gain
Set output gain. Default is 0.74
delay
Set delay in milliseconds. Default is 3.0.
decay
Set decay. Default is 0.4.
speed
Set modulation speed in Hz. Default is 0.5.
type
Set modulation type. Default is triangular.
It accepts the following values:
triangular, t
sinusoidal, s
aphaseshift
Apply phase shift to input audio samples.
The filter accepts the following options:
shift
Specify phase shift. Allowed range is from -1.0 to 1.0. Default value is 0.0.
level
Set output gain applied to final output. Allowed range is from 0.0 to 1.0. Default
value is 1.0.
order
Set filter order used for filtering. Allowed range is from 1 to 16. Default value is
8.
Commands
This filter supports the all above options as commands.
apsnr
Measure Audio Peak Signal-to-Noise Ratio.
This filter takes two audio streams for input, and outputs first audio stream. Results
are in dB per channel at end of either input.
apsyclip
Apply Psychoacoustic clipper to input audio stream.
The filter accepts the following options:
level_in
Set input gain. By default it is 1. Range is [0.015625 - 64].
level_out
Set output gain. By default it is 1. Range is [0.015625 - 64].
clip
Set the clipping start value. Default value is 0dBFS or 1.
diff
Output only difference samples, useful to hear introduced distortions. By default is
disabled.
adaptive
Set strength of adaptive distortion applied. Default value is 0.5. Allowed range is
from 0 to 1.
iterations
Set number of iterations of psychoacoustic clipper. Allowed range is from 1 to 20.
Default value is 10.
level
Auto level output signal. Default is disabled. This normalizes audio back to 0dBFS if
enabled.
Commands
This filter supports the all above options as commands.
apulsator
Audio pulsator is something between an autopanner and a tremolo. But it can produce funny
stereo effects as well. Pulsator changes the volume of the left and right channel based on
a LFO (low frequency oscillator) with different waveforms and shifted phases. This filter
have the ability to define an offset between left and right channel. An offset of 0 means
that both LFO shapes match each other. The left and right channel are altered equally - a
conventional tremolo. An offset of 50% means that the shape of the right channel is
exactly shifted in phase (or moved backwards about half of the frequency) - pulsator acts
as an autopanner. At 1 both curves match again. Every setting in between moves the phase
shift gapless between all stages and produces some "bypassing" sounds with sine and
triangle waveforms. The more you set the offset near 1 (starting from the 0.5) the faster
the signal passes from the left to the right speaker.
The filter accepts the following options:
level_in
Set input gain. By default it is 1. Range is [0.015625 - 64].
level_out
Set output gain. By default it is 1. Range is [0.015625 - 64].
mode
Set waveform shape the LFO will use. Can be one of: sine, triangle, square, sawup or
sawdown. Default is sine.
amount
Set modulation. Define how much of original signal is affected by the LFO.
offset_l
Set left channel offset. Default is 0. Allowed range is [0 - 1].
offset_r
Set right channel offset. Default is 0.5. Allowed range is [0 - 1].
width
Set pulse width. Default is 1. Allowed range is [0 - 2].
timing
Set possible timing mode. Can be one of: bpm, ms or hz. Default is hz.
bpm Set bpm. Default is 120. Allowed range is [30 - 300]. Only used if timing is set to
bpm.
ms Set ms. Default is 500. Allowed range is [10 - 2000]. Only used if timing is set to
ms.
hz Set frequency in Hz. Default is 2. Allowed range is [0.01 - 100]. Only used if timing
is set to hz.
aresample
Resample the input audio to the specified parameters, using the libswresample library. If
none are specified then the filter will automatically convert between its input and
output.
This filter is also able to stretch/squeeze the audio data to make it match the timestamps
or to inject silence / cut out audio to make it match the timestamps, do a combination of
both or do neither.
The filter accepts the syntax [sample_rate:]resampler_options, where sample_rate expresses
a sample rate and resampler_options is a list of key=value pairs, separated by ":". See
the "Resampler Options" section in the ffmpeg-resampler(1) manual for the complete list of
supported options.
Examples
• Resample the input audio to 44100Hz:
aresample=44100
• Stretch/squeeze samples to the given timestamps, with a maximum of 1000 samples per
second compensation:
aresample=async=1000
areverse
Reverse an audio clip.
Warning: This filter requires memory to buffer the entire clip, so trimming is suggested.
Examples
• Take the first 5 seconds of a clip, and reverse it.
atrim=end=5,areverse
arls
Apply Recursive Least Squares algorithm to the first audio stream using the second audio
stream.
This adaptive filter is used to mimic a desired filter by recursively finding the filter
coefficients that relate to producing the minimal weighted linear least squares cost
function of the error signal (difference between the desired, 2nd input audio stream and
the actual signal, the 1st input audio stream).
A description of the accepted options follows.
order
Set the filter order.
lambda
Set the forgetting factor.
delta
Set the coefficient to initialize internal covariance matrix.
out_mode
Set the filter output samples. It accepts the following values:
i Pass the 1st input.
d Pass the 2nd input.
o Pass difference between desired, 2nd input and error signal estimate.
n Pass difference between input, 1st input and error signal estimate.
e Pass error signal estimated samples.
Default value is o.
precision
Set which precision to use when processing samples.
auto
Auto pick internal sample format depending on other filters.
float
Always use single-floating point precision sample format.
double
Always use double-floating point precision sample format.
arnndn
Reduce noise from speech using Recurrent Neural Networks.
This filter accepts the following options:
model, m
Set train model file to load. This option is always required.
mix Set how much to mix filtered samples into final output. Allowed range is from -1 to
1. Default value is 1. Negative values are special, they set how much to keep
filtered noise in the final filter output. Set this option to -1 to hear actual noise
removed from input signal.
Commands
This filter supports the all above options as commands.
asdr
Measure Audio Signal-to-Distortion Ratio.
This filter takes two audio streams for input, and outputs first audio stream. Results
are in dB per channel at end of either input.
asetnsamples
Set the number of samples per each output audio frame.
The last output packet may contain a different number of samples, as the filter will flush
all the remaining samples when the input audio signals its end.
The filter accepts the following options:
nb_out_samples, n
Set the number of frames per each output audio frame. The number is intended as the
number of samples per each channel. Default value is 1024.
pad, p
If set to 1, the filter will pad the last audio frame with zeroes, so that the last
frame will contain the same number of samples as the previous ones. Default value is
1.
For example, to set the number of per-frame samples to 1234 and disable padding for the
last frame, use:
asetnsamples=n=1234:p=0
asetrate
Set the sample rate without altering the PCM data. This will result in a change of speed
and pitch.
The filter accepts the following options:
sample_rate, r
Set the output sample rate. Default is 44100 Hz.
ashowinfo
Show a line containing various information for each input audio frame. The input audio is
not modified.
The shown line contains a sequence of key/value pairs of the form key:value.
The following values are shown in the output:
n The (sequential) number of the input frame, starting from 0.
pts The presentation timestamp of the input frame, in time base units; the time base
depends on the filter input pad, and is usually 1/sample_rate.
pts_time
The presentation timestamp of the input frame in seconds.
fmt The sample format.
chlayout
The channel layout.
rate
The sample rate for the audio frame.
nb_samples
The number of samples (per channel) in the frame.
checksum
The Adler-32 checksum (printed in hexadecimal) of the audio data. For planar audio,
the data is treated as if all the planes were concatenated.
plane_checksums
A list of Adler-32 checksums for each data plane.
asisdr
Measure Audio Scaled-Invariant Signal-to-Distortion Ratio.
This filter takes two audio streams for input, and outputs first audio stream. Results
are in dB per channel at end of either input.
asoftclip
Apply audio soft clipping.
Soft clipping is a type of distortion effect where the amplitude of a signal is saturated
along a smooth curve, rather than the abrupt shape of hard-clipping.
This filter accepts the following options:
type
Set type of soft-clipping.
It accepts the following values:
hard
tanh
atan
cubic
exp
alg
quintic
sin
erf
threshold
Set threshold from where to start clipping. Default value is 0dB or 1.
output
Set gain applied to output. Default value is 0dB or 1.
param
Set additional parameter which controls sigmoid function.
oversample
Set oversampling factor.
Commands
This filter supports the all above options as commands.
aspectralstats
Display frequency domain statistical information about the audio channels. Statistics are
calculated and stored as metadata for each audio channel and for each audio frame.
It accepts the following option:
win_size
Set the window length in samples. Default value is 2048. Allowed range is from 32 to
65536.
win_func
Set window function.
It accepts the following values:
rect
bartlett
hann, hanning
hamming
blackman
welch
flattop
bharris
bnuttall
bhann
sine
nuttall
lanczos
gauss
tukey
dolph
cauchy
parzen
poisson
bohman
kaiser
Default is "hann".
overlap
Set window overlap. Allowed range is from 0 to 1. Default value is 0.5.
measure
Select the parameters which are measured. The metadata keys can be used as flags,
default is all which measures everything. none disables all measurement.
A list of each metadata key follows:
mean
variance
centroid
spread
skewness
kurtosis
entropy
flatness
crest
flux
slope
decrease
rolloff
asr
Automatic Speech Recognition
This filter uses PocketSphinx for speech recognition. To enable compilation of this
filter, you need to configure FFmpeg with "--enable-pocketsphinx".
It accepts the following options:
rate
Set sampling rate of input audio. Defaults is 16000. This need to match speech
models, otherwise one will get poor results.
hmm Set dictionary containing acoustic model files.
dict
Set pronunciation dictionary.
lm Set language model file.
lmctl
Set language model set.
lmname
Set which language model to use.
logfn
Set output for log messages.
The filter exports recognized speech as the frame metadata "lavfi.asr.text".
astats
Display time domain statistical information about the audio channels. Statistics are
calculated and displayed for each audio channel and, where applicable, an overall figure
is also given.
It accepts the following option:
length
Short window length in seconds, used for peak and trough RMS measurement. Default is
0.05 (50 milliseconds). Allowed range is "[0 - 10]".
metadata
Set metadata injection. All the metadata keys are prefixed with "lavfi.astats.X",
where "X" is channel number starting from 1 or string "Overall". Default is disabled.
Available keys for each channel are: Bit_depth Crest_factor DC_offset Dynamic_range
Entropy Flat_factor Max_difference Max_level Mean_difference Min_difference Min_level
Noise_floor Noise_floor_count Number_of_Infs Number_of_NaNs Number_of_denormals
Peak_count Abs_Peak_count Peak_level RMS_difference RMS_peak RMS_trough Zero_crossings
Zero_crossings_rate
and for "Overall": Bit_depth DC_offset Entropy Flat_factor Max_difference Max_level
Mean_difference Min_difference Min_level Noise_floor Noise_floor_count Number_of_Infs
Number_of_NaNs Number_of_denormals Number_of_samples Peak_count Abs_Peak_count
Peak_level RMS_difference RMS_level RMS_peak RMS_trough
For example, a full key looks like "lavfi.astats.1.DC_offset" or
"lavfi.astats.Overall.Peak_count".
Read below for the description of the keys.
reset
Set the number of frames over which cumulative stats are calculated before being
reset. Default is disabled.
measure_perchannel
Select the parameters which are measured per channel. The metadata keys can be used as
flags, default is all which measures everything. none disables all per channel
measurement.
measure_overall
Select the parameters which are measured overall. The metadata keys can be used as
flags, default is all which measures everything. none disables all overall
measurement.
A description of the measure keys follow:
none
no measures
all all measures
Bit_depth
overall bit depth of audio, i.e. number of bits used for each sample
Crest_factor
standard ratio of peak to RMS level (note: not in dB)
DC_offset
mean amplitude displacement from zero
Dynamic_range
measured dynamic range of audio in dB
Entropy
entropy measured across whole audio, entropy of value near 1.0 is typically measured
for white noise
Flat_factor
flatness (i.e. consecutive samples with the same value) of the signal at its peak
levels (i.e. either Min_level or Max_level)
Max_difference
maximal difference between two consecutive samples
Max_level
maximal sample level
Mean_difference
mean difference between two consecutive samples, i.e. the average of each difference
between two consecutive samples
Min_difference
minimal difference between two consecutive samples
Min_level
minimal sample level
Noise_floor
minimum local peak measured in dBFS over a short window
Noise_floor_count
number of occasions (not the number of samples) that the signal attained Noise floor
Number_of_Infs
number of samples with an infinite value
Number_of_NaNs
number of samples with a NaN (not a number) value
Number_of_denormals
number of samples with a subnormal value
Number_of_samples
number of samples
Peak_count
number of occasions (not the number of samples) that the signal attained either
Min_level or Max_level
Abs_Peak_count
number of occasions that the absolute samples taken from the signal attained max
absolute value of Min_level and Max_level
Peak_level
standard peak level measured in dBFS
RMS_difference
Root Mean Square difference between two consecutive samples
RMS_level
standard RMS level measured in dBFS
RMS_peak
RMS_trough
peak and trough values for RMS level measured over a short window, measured in dBFS.
Zero crossings
number of points where the waveform crosses the zero level axis
Zero crossings rate
rate of Zero crossings and number of audio samples
asubboost
Boost subwoofer frequencies.
The filter accepts the following options:
dry Set dry gain, how much of original signal is kept. Allowed range is from 0 to 1.
Default value is 1.0.
wet Set wet gain, how much of filtered signal is kept. Allowed range is from 0 to 1.
Default value is 1.0.
boost
Set max boost factor. Allowed range is from 1 to 12. Default value is 2.
decay
Set delay line decay gain value. Allowed range is from 0 to 1. Default value is 0.0.
feedback
Set delay line feedback gain value. Allowed range is from 0 to 1. Default value is
0.9.
cutoff
Set cutoff frequency in Hertz. Allowed range is 50 to 900. Default value is 100.
slope
Set slope amount for cutoff frequency. Allowed range is 0.0001 to 1. Default value is
0.5.
delay
Set delay. Allowed range is from 1 to 100. Default value is 20.
channels
Set the channels to process. Default value is all available.
Commands
This filter supports the all above options as commands.
asubcut
Cut subwoofer frequencies.
This filter allows to set custom, steeper roll off than highpass filter, and thus is able
to more attenuate frequency content in stop-band.
The filter accepts the following options:
cutoff
Set cutoff frequency in Hertz. Allowed range is 2 to 200. Default value is 20.
order
Set filter order. Available values are from 3 to 20. Default value is 10.
level
Set input gain level. Allowed range is from 0 to 1. Default value is 1.
Commands
This filter supports the all above options as commands.
asupercut
Cut super frequencies.
The filter accepts the following options:
cutoff
Set cutoff frequency in Hertz. Allowed range is 20000 to 192000. Default value is
20000.
order
Set filter order. Available values are from 3 to 20. Default value is 10.
level
Set input gain level. Allowed range is from 0 to 1. Default value is 1.
Commands
This filter supports the all above options as commands.
asuperpass
Apply high order Butterworth band-pass filter.
The filter accepts the following options:
centerf
Set center frequency in Hertz. Allowed range is 2 to 999999. Default value is 1000.
order
Set filter order. Available values are from 4 to 20. Default value is 4.
qfactor
Set Q-factor. Allowed range is from 0.01 to 100. Default value is 1.
level
Set input gain level. Allowed range is from 0 to 2. Default value is 1.
Commands
This filter supports the all above options as commands.
asuperstop
Apply high order Butterworth band-stop filter.
The filter accepts the following options:
centerf
Set center frequency in Hertz. Allowed range is 2 to 999999. Default value is 1000.
order
Set filter order. Available values are from 4 to 20. Default value is 4.
qfactor
Set Q-factor. Allowed range is from 0.01 to 100. Default value is 1.
level
Set input gain level. Allowed range is from 0 to 2. Default value is 1.
Commands
This filter supports the all above options as commands.
atempo
Adjust audio tempo.
The filter accepts exactly one parameter, the audio tempo. If not specified then the
filter will assume nominal 1.0 tempo. Tempo must be in the [0.5, 100.0] range.
Note that tempo greater than 2 will skip some samples rather than blend them in. If for
any reason this is a concern it is always possible to daisy-chain several instances of
atempo to achieve the desired product tempo.
Examples
• Slow down audio to 80% tempo:
atempo=0.8
• To speed up audio to 300% tempo:
atempo=3
• To speed up audio to 300% tempo by daisy-chaining two atempo instances:
atempo=sqrt(3),atempo=sqrt(3)
Commands
This filter supports the following commands:
tempo
Change filter tempo scale factor. Syntax for the command is : "tempo"
atilt
Apply spectral tilt filter to audio stream.
This filter apply any spectral roll-off slope over any specified frequency band.
The filter accepts the following options:
freq
Set central frequency of tilt in Hz. Default is 10000 Hz.
slope
Set slope direction of tilt. Default is 0. Allowed range is from -1 to 1.
width
Set width of tilt. Default is 1000. Allowed range is from 100 to 10000.
order
Set order of tilt filter.
level
Set input volume level. Allowed range is from 0 to 4. Default is 1.
Commands
This filter supports the all above options as commands.
atrim
Trim the input so that the output contains one continuous subpart of the input.
It accepts the following parameters:
start
Timestamp (in seconds) of the start of the section to keep. I.e. the audio sample with
the timestamp start will be the first sample in the output.
end Specify time of the first audio sample that will be dropped, i.e. the audio sample
immediately preceding the one with the timestamp end will be the last sample in the
output.
start_pts
Same as start, except this option sets the start timestamp in samples instead of
seconds.
end_pts
Same as end, except this option sets the end timestamp in samples instead of seconds.
duration
The maximum duration of the output in seconds.
start_sample
The number of the first sample that should be output.
end_sample
The number of the first sample that should be dropped.
start, end, and duration are expressed as time duration specifications; see the Time
duration section in the ffmpeg-utils(1) manual.
Note that the first two sets of the start/end options and the duration option look at the
frame timestamp, while the _sample options simply count the samples that pass through the
filter. So start/end_pts and start/end_sample will give different results when the
timestamps are wrong, inexact or do not start at zero. Also note that this filter does not
modify the timestamps. If you wish to have the output timestamps start at zero, insert the
asetpts filter after the atrim filter.
If multiple start or end options are set, this filter tries to be greedy and keep all
samples that match at least one of the specified constraints. To keep only the part that
matches all the constraints at once, chain multiple atrim filters.
The defaults are such that all the input is kept. So it is possible to set e.g. just the
end values to keep everything before the specified time.
Examples:
• Drop everything except the second minute of input:
ffmpeg -i INPUT -af atrim=60:120
• Keep only the first 1000 samples:
ffmpeg -i INPUT -af atrim=end_sample=1000
axcorrelate
Calculate normalized windowed cross-correlation between two input audio streams.
Resulted samples are always between -1 and 1 inclusive. If result is 1 it means two input
samples are highly correlated in that selected segment. Result 0 means they are not
correlated at all. If result is -1 it means two input samples are out of phase, which
means they cancel each other.
The filter accepts the following options:
size
Set size of segment over which cross-correlation is calculated. Default is 256.
Allowed range is from 2 to 131072.
algo
Set algorithm for cross-correlation. Can be "slow" or "fast" or "best". Default is
"best". Fast algorithm assumes mean values over any given segment are always zero and
thus need much less calculations to make. This is generally not true, but is valid
for typical audio streams.
Examples
• Calculate correlation between channels in stereo audio stream:
ffmpeg -i stereo.wav -af channelsplit,axcorrelate=size=1024:algo=fast correlation.wav
bandpass
Apply a two-pole Butterworth band-pass filter with central frequency frequency, and
(3dB-point) band-width width. The csg option selects a constant skirt gain (peak gain =
Q) instead of the default: constant 0dB peak gain. The filter roll off at 6dB per octave
(20dB per decade).
The filter accepts the following options:
frequency, f
Set the filter's central frequency. Default is 3000.
csg Constant skirt gain if set to 1. Defaults to 0.
width_type, t
Set method to specify band-width of filter.
h Hz
q Q-Factor
o octave
s slope
k kHz
width, w
Specify the band-width of a filter in width_type units.
mix, m
How much to use filtered signal in output. Default is 1. Range is between 0 and 1.
channels, c
Specify which channels to filter, by default all available are filtered.
normalize, n
Normalize biquad coefficients, by default is disabled. Enabling it will normalize
magnitude response at DC to 0dB.
transform, a
Set transform type of IIR filter.
di
dii
tdi
tdii
latt
svf
zdf
precision, r
Set precision of filtering.
auto
Pick automatic sample format depending on surround filters.
s16 Always use signed 16-bit.
s32 Always use signed 32-bit.
f32 Always use float 32-bit.
f64 Always use float 64-bit.
block_size, b
Set block size used for reverse IIR processing. If this value is set to high enough
value (higher than impulse response length truncated when reaches near zero values)
filtering will become linear phase otherwise if not big enough it will just produce
nasty artifacts.
Note that filter delay will be exactly this many samples when set to non-zero value.
Commands
This filter supports the following commands:
frequency, f
Change bandpass frequency. Syntax for the command is : "frequency"
width_type, t
Change bandpass width_type. Syntax for the command is : "width_type"
width, w
Change bandpass width. Syntax for the command is : "width"
mix, m
Change bandpass mix. Syntax for the command is : "mix"
bandreject
Apply a two-pole Butterworth band-reject filter with central frequency frequency, and
(3dB-point) band-width width. The filter roll off at 6dB per octave (20dB per decade).
The filter accepts the following options:
frequency, f
Set the filter's central frequency. Default is 3000.
width_type, t
Set method to specify band-width of filter.
h Hz
q Q-Factor
o octave
s slope
k kHz
width, w
Specify the band-width of a filter in width_type units.
mix, m
How much to use filtered signal in output. Default is 1. Range is between 0 and 1.
channels, c
Specify which channels to filter, by default all available are filtered.
normalize, n
Normalize biquad coefficients, by default is disabled. Enabling it will normalize
magnitude response at DC to 0dB.
transform, a
Set transform type of IIR filter.
di
dii
tdi
tdii
latt
svf
zdf
precision, r
Set precision of filtering.
auto
Pick automatic sample format depending on surround filters.
s16 Always use signed 16-bit.
s32 Always use signed 32-bit.
f32 Always use float 32-bit.
f64 Always use float 64-bit.
block_size, b
Set block size used for reverse IIR processing. If this value is set to high enough
value (higher than impulse response length truncated when reaches near zero values)
filtering will become linear phase otherwise if not big enough it will just produce
nasty artifacts.
Note that filter delay will be exactly this many samples when set to non-zero value.
Commands
This filter supports the following commands:
frequency, f
Change bandreject frequency. Syntax for the command is : "frequency"
width_type, t
Change bandreject width_type. Syntax for the command is : "width_type"
width, w
Change bandreject width. Syntax for the command is : "width"
mix, m
Change bandreject mix. Syntax for the command is : "mix"
bass, lowshelf
Boost or cut the bass (lower) frequencies of the audio using a two-pole shelving filter
with a response similar to that of a standard hi-fi's tone-controls. This is also known as
shelving equalisation (EQ).
The filter accepts the following options:
gain, g
Give the gain at 0 Hz. Its useful range is about -20 (for a large cut) to +20 (for a
large boost). Beware of clipping when using a positive gain.
frequency, f
Set the filter's central frequency and so can be used to extend or reduce the
frequency range to be boosted or cut. The default value is 100 Hz.
width_type, t
Set method to specify band-width of filter.
h Hz
q Q-Factor
o octave
s slope
k kHz
width, w
Determine how steep is the filter's shelf transition.
poles, p
Set number of poles. Default is 2.
mix, m
How much to use filtered signal in output. Default is 1. Range is between 0 and 1.
channels, c
Specify which channels to filter, by default all available are filtered.
normalize, n
Normalize biquad coefficients, by default is disabled. Enabling it will normalize
magnitude response at DC to 0dB.
transform, a
Set transform type of IIR filter.
di
dii
tdi
tdii
latt
svf
zdf
precision, r
Set precision of filtering.
auto
Pick automatic sample format depending on surround filters.
s16 Always use signed 16-bit.
s32 Always use signed 32-bit.
f32 Always use float 32-bit.
f64 Always use float 64-bit.
block_size, b
Set block size used for reverse IIR processing. If this value is set to high enough
value (higher than impulse response length truncated when reaches near zero values)
filtering will become linear phase otherwise if not big enough it will just produce
nasty artifacts.
Note that filter delay will be exactly this many samples when set to non-zero value.
Commands
This filter supports the following commands:
frequency, f
Change bass frequency. Syntax for the command is : "frequency"
width_type, t
Change bass width_type. Syntax for the command is : "width_type"
width, w
Change bass width. Syntax for the command is : "width"
gain, g
Change bass gain. Syntax for the command is : "gain"
mix, m
Change bass mix. Syntax for the command is : "mix"
biquad
Apply a biquad IIR filter with the given coefficients. Where b0, b1, b2 and a0, a1, a2
are the numerator and denominator coefficients respectively. and channels, c specify
which channels to filter, by default all available are filtered.
Commands
This filter supports the following commands:
a0
a1
a2
b0
b1
b2 Change biquad parameter. Syntax for the command is : "value"
mix, m
How much to use filtered signal in output. Default is 1. Range is between 0 and 1.
channels, c
Specify which channels to filter, by default all available are filtered.
normalize, n
Normalize biquad coefficients, by default is disabled. Enabling it will normalize
magnitude response at DC to 0dB.
transform, a
Set transform type of IIR filter.
di
dii
tdi
tdii
latt
svf
zdf
precision, r
Set precision of filtering.
auto
Pick automatic sample format depending on surround filters.
s16 Always use signed 16-bit.
s32 Always use signed 32-bit.
f32 Always use float 32-bit.
f64 Always use float 64-bit.
block_size, b
Set block size used for reverse IIR processing. If this value is set to high enough
value (higher than impulse response length truncated when reaches near zero values)
filtering will become linear phase otherwise if not big enough it will just produce
nasty artifacts.
Note that filter delay will be exactly this many samples when set to non-zero value.
bs2b
Bauer stereo to binaural transformation, which improves headphone listening of stereo
audio records.
To enable compilation of this filter you need to configure FFmpeg with "--enable-libbs2b".
It accepts the following parameters:
profile
Pre-defined crossfeed level.
default
Default level (fcut=700, feed=50).
cmoy
Chu Moy circuit (fcut=700, feed=60).
jmeier
Jan Meier circuit (fcut=650, feed=95).
fcut
Cut frequency (in Hz).
feed
Feed level (in Hz).
channelmap
Remap input channels to new locations.
It accepts the following parameters:
map Map channels from input to output. The argument is a '|'-separated list of mappings,
each in the "in_channel-out_channel" or "in_channel" form. in_channel can be either
the name of the input channel (e.g. FL for front left) or its index in the input
channel layout. out_channel is the name of the output channel or its index in the
output channel layout. If out_channel is not given then it is implicitly an index,
starting with zero and increasing by one for each mapping. Mixing different types of
mappings is not allowed and will result in a parse error.
channel_layout
The channel layout of the output stream. If not specified, then filter will guess it
based on the out_channel names or the number of mappings. Guessed layouts will not
necessarily contain channels in the order of the mappings.
If no mapping is present, the filter will implicitly map input channels to output
channels, preserving indices.
Examples
• For example, assuming a 5.1+downmix input MOV file,
ffmpeg -i in.mov -filter 'channelmap=map=DL-FL|DR-FR' out.wav
will create an output WAV file tagged as stereo from the downmix channels of the
input.
• To fix a 5.1 WAV improperly encoded in AAC's native channel order
ffmpeg -i in.wav -filter 'channelmap=1|2|0|5|3|4:5.1' out.wav
channelsplit
Split each channel from an input audio stream into a separate output stream.
It accepts the following parameters:
channel_layout
The channel layout of the input stream. The default is "stereo".
channels
A channel layout describing the channels to be extracted as separate output streams or
"all" to extract each input channel as a separate stream. The default is "all".
Choosing channels not present in channel layout in the input will result in an error.
Examples
• For example, assuming a stereo input MP3 file,
ffmpeg -i in.mp3 -filter_complex channelsplit out.mkv
will create an output Matroska file with two audio streams, one containing only the
left channel and the other the right channel.
• Split a 5.1 WAV file into per-channel files:
ffmpeg -i in.wav -filter_complex
'channelsplit=channel_layout=5.1[FL][FR][FC][LFE][SL][SR]'
-map '[FL]' front_left.wav -map '[FR]' front_right.wav -map '[FC]'
front_center.wav -map '[LFE]' lfe.wav -map '[SL]' side_left.wav -map '[SR]'
side_right.wav
• Extract only LFE from a 5.1 WAV file:
ffmpeg -i in.wav -filter_complex 'channelsplit=channel_layout=5.1:channels=LFE[LFE]'
-map '[LFE]' lfe.wav
chorus
Add a chorus effect to the audio.
Can make a single vocal sound like a chorus, but can also be applied to instrumentation.
Chorus resembles an echo effect with a short delay, but whereas with echo the delay is
constant, with chorus, it is varied using using sinusoidal or triangular modulation. The
modulation depth defines the range the modulated delay is played before or after the
delay. Hence the delayed sound will sound slower or faster, that is the delayed sound
tuned around the original one, like in a chorus where some vocals are slightly off key.
It accepts the following parameters:
in_gain
Set input gain. Default is 0.4.
out_gain
Set output gain. Default is 0.4.
delays
Set delays. A typical delay is around 40ms to 60ms.
decays
Set decays.
speeds
Set speeds.
depths
Set depths.
Examples
• A single delay:
chorus=0.7:0.9:55:0.4:0.25:2
• Two delays:
chorus=0.6:0.9:50|60:0.4|0.32:0.25|0.4:2|1.3
• Fuller sounding chorus with three delays:
chorus=0.5:0.9:50|60|40:0.4|0.32|0.3:0.25|0.4|0.3:2|2.3|1.3
compand
Compress or expand the audio's dynamic range.
It accepts the following parameters:
attacks
decays
A list of times in seconds for each channel over which the instantaneous level of the
input signal is averaged to determine its volume. attacks refers to increase of volume
and decays refers to decrease of volume. For most situations, the attack time
(response to the audio getting louder) should be shorter than the decay time, because
the human ear is more sensitive to sudden loud audio than sudden soft audio. A typical
value for attack is 0.3 seconds and a typical value for decay is 0.8 seconds. If
specified number of attacks & decays is lower than number of channels, the last set
attack/decay will be used for all remaining channels.
points
A list of points for the transfer function, specified in dB relative to the maximum
possible signal amplitude. Each key points list must be defined using the following
syntax: "x0/y0|x1/y1|x2/y2|...." or "x0/y0 x1/y1 x2/y2 ...."
The input values must be in strictly increasing order but the transfer function does
not have to be monotonically rising. The point "0/0" is assumed but may be overridden
(by "0/out-dBn"). Typical values for the transfer function are "-70/-70|-60/-20|1/0".
soft-knee
Set the curve radius in dB for all joints. It defaults to 0.01.
gain
Set the additional gain in dB to be applied at all points on the transfer function.
This allows for easy adjustment of the overall gain. It defaults to 0.
volume
Set an initial volume, in dB, to be assumed for each channel when filtering starts.
This permits the user to supply a nominal level initially, so that, for example, a
very large gain is not applied to initial signal levels before the companding has
begun to operate. A typical value for audio which is initially quiet is -90 dB. It
defaults to 0.
delay
Set a delay, in seconds. The input audio is analyzed immediately, but audio is delayed
before being fed to the volume adjuster. Specifying a delay approximately equal to the
attack/decay times allows the filter to effectively operate in predictive rather than
reactive mode. It defaults to 0.
Examples
• Make music with both quiet and loud passages suitable for listening to in a noisy
environment:
compand=.3|.3:1|1:-90/-60|-60/-40|-40/-30|-20/-20:6:0:-90:0.2
Another example for audio with whisper and explosion parts:
compand=0|0:1|1:-90/-900|-70/-70|-30/-9|0/-3:6:0:0:0
• A noise gate for when the noise is at a lower level than the signal:
compand=.1|.1:.2|.2:-900/-900|-50.1/-900|-50/-50:.01:0:-90:.1
• Here is another noise gate, this time for when the noise is at a higher level than the
signal (making it, in some ways, similar to squelch):
compand=.1|.1:.1|.1:-45.1/-45.1|-45/-900|0/-900:.01:45:-90:.1
• 2:1 compression starting at -6dB:
compand=points=-80/-80|-6/-6|0/-3.8|20/3.5
• 2:1 compression starting at -9dB:
compand=points=-80/-80|-9/-9|0/-5.3|20/2.9
• 2:1 compression starting at -12dB:
compand=points=-80/-80|-12/-12|0/-6.8|20/1.9
• 2:1 compression starting at -18dB:
compand=points=-80/-80|-18/-18|0/-9.8|20/0.7
• 3:1 compression starting at -15dB:
compand=points=-80/-80|-15/-15|0/-10.8|20/-5.2
• Compressor/Gate:
compand=points=-80/-105|-62/-80|-15.4/-15.4|0/-12|20/-7.6
• Expander:
compand=attacks=0:points=-80/-169|-54/-80|-49.5/-64.6|-41.1/-41.1|-25.8/-15|-10.8/-4.5|0/0|20/8.3
• Hard limiter at -6dB:
compand=attacks=0:points=-80/-80|-6/-6|20/-6
• Hard limiter at -12dB:
compand=attacks=0:points=-80/-80|-12/-12|20/-12
• Hard noise gate at -35 dB:
compand=attacks=0:points=-80/-115|-35.1/-80|-35/-35|20/20
• Soft limiter:
compand=attacks=0:points=-80/-80|-12.4/-12.4|-6/-8|0/-6.8|20/-2.8
compensationdelay
Compensation Delay Line is a metric based delay to compensate differing positions of
microphones or speakers.
For example, you have recorded guitar with two microphones placed in different locations.
Because the front of sound wave has fixed speed in normal conditions, the phasing of
microphones can vary and depends on their location and interposition. The best sound mix
can be achieved when these microphones are in phase (synchronized). Note that a distance
of ~30 cm between microphones makes one microphone capture the signal in antiphase to the
other microphone. That makes the final mix sound moody. This filter helps to solve
phasing problems by adding different delays to each microphone track and make them
synchronized.
The best result can be reached when you take one track as base and synchronize other
tracks one by one with it. Remember that synchronization/delay tolerance depends on
sample rate, too. Higher sample rates will give more tolerance.
The filter accepts the following parameters:
mm Set millimeters distance. This is compensation distance for fine tuning. Default is
0.
cm Set cm distance. This is compensation distance for tightening distance setup. Default
is 0.
m Set meters distance. This is compensation distance for hard distance setup. Default
is 0.
dry Set dry amount. Amount of unprocessed (dry) signal. Default is 0.
wet Set wet amount. Amount of processed (wet) signal. Default is 1.
temp
Set temperature in degrees Celsius. This is the temperature of the environment.
Default is 20.
Commands
This filter supports the all above options as commands.
crossfeed
Apply headphone crossfeed filter.
Crossfeed is the process of blending the left and right channels of stereo audio
recording. It is mainly used to reduce extreme stereo separation of low frequencies.
The intent is to produce more speaker like sound to the listener.
The filter accepts the following options:
strength
Set strength of crossfeed. Default is 0.2. Allowed range is from 0 to 1. This sets
gain of low shelf filter for side part of stereo image. Default is -6dB. Max allowed
is -30db when strength is set to 1.
range
Set soundstage wideness. Default is 0.5. Allowed range is from 0 to 1. This sets cut
off frequency of low shelf filter. Default is cut off near 1550 Hz. With range set to
1 cut off frequency is set to 2100 Hz.
slope
Set curve slope of low shelf filter. Default is 0.5. Allowed range is from 0.01 to 1.
level_in
Set input gain. Default is 0.9.
level_out
Set output gain. Default is 1.
block_size
Set block size used for reverse IIR processing. If this value is set to high enough
value (higher than impulse response length truncated when reaches near zero values)
filtering will become linear phase otherwise if not big enough it will just produce
nasty artifacts.
Note that filter delay will be exactly this many samples when set to non-zero value.
Commands
This filter supports the all above options as commands.
crystalizer
Simple algorithm for audio noise sharpening.
This filter linearly increases differences between each audio sample.
The filter accepts the following options:
i Sets the intensity of effect (default: 2.0). Must be in range between -10.0 to 0
(unchanged sound) to 10.0 (maximum effect). To inverse filtering use negative value.
c Enable clipping. By default is enabled.
Commands
This filter supports the all above options as commands.
dcshift
Apply a DC shift to the audio.
This can be useful to remove a DC offset (caused perhaps by a hardware problem in the
recording chain) from the audio. The effect of a DC offset is reduced headroom and hence
volume. The astats filter can be used to determine if a signal has a DC offset.
shift
Set the DC shift, allowed range is [-1, 1]. It indicates the amount to shift the
audio.
limitergain
Optional. It should have a value much less than 1 (e.g. 0.05 or 0.02) and is used to
prevent clipping.
deesser
Apply de-essing to the audio samples.
i Set intensity for triggering de-essing. Allowed range is from 0 to 1. Default is 0.
m Set amount of ducking on treble part of sound. Allowed range is from 0 to 1. Default
is 0.5.
f How much of original frequency content to keep when de-essing. Allowed range is from 0
to 1. Default is 0.5.
s Set the output mode.
It accepts the following values:
i Pass input unchanged.
o Pass ess filtered out.
e Pass only ess.
Default value is o.
dialoguenhance
Enhance dialogue in stereo audio.
This filter accepts stereo input and produce surround (3.0) channels output. The newly
produced front center channel have enhanced speech dialogue originally available in both
stereo channels. This filter outputs front left and front right channels same as
available in stereo input.
The filter accepts the following options:
original
Set the original center factor to keep in front center channel output. Allowed range
is from 0 to 1. Default value is 1.
enhance
Set the dialogue enhance factor to put in front center channel output. Allowed range
is from 0 to 3. Default value is 1.
voice
Set the voice detection factor. Allowed range is from 2 to 32. Default value is 2.
Commands
This filter supports the all above options as commands.
drmeter
Measure audio dynamic range.
DR values of 14 and higher is found in very dynamic material. DR of 8 to 13 is found in
transition material. And anything less that 8 have very poor dynamics and is very
compressed.
The filter accepts the following options:
length
Set window length in seconds used to split audio into segments of equal length.
Default is 3 seconds.
dynaudnorm
Dynamic Audio Normalizer.
This filter applies a certain amount of gain to the input audio in order to bring its peak
magnitude to a target level (e.g. 0 dBFS). However, in contrast to more "simple"
normalization algorithms, the Dynamic Audio Normalizer *dynamically* re-adjusts the gain
factor to the input audio. This allows for applying extra gain to the "quiet" sections of
the audio while avoiding distortions or clipping the "loud" sections. In other words: The
Dynamic Audio Normalizer will "even out" the volume of quiet and loud sections, in the
sense that the volume of each section is brought to the same target level. Note, however,
that the Dynamic Audio Normalizer achieves this goal *without* applying "dynamic range
compressing". It will retain 100% of the dynamic range *within* each section of the audio
file.
framelen, f
Set the frame length in milliseconds. In range from 10 to 8000 milliseconds. Default
is 500 milliseconds. The Dynamic Audio Normalizer processes the input audio in small
chunks, referred to as frames. This is required, because a peak magnitude has no
meaning for just a single sample value. Instead, we need to determine the peak
magnitude for a contiguous sequence of sample values. While a "standard" normalizer
would simply use the peak magnitude of the complete file, the Dynamic Audio Normalizer
determines the peak magnitude individually for each frame. The length of a frame is
specified in milliseconds. By default, the Dynamic Audio Normalizer uses a frame
length of 500 milliseconds, which has been found to give good results with most files.
Note that the exact frame length, in number of samples, will be determined
automatically, based on the sampling rate of the individual input audio file.
gausssize, g
Set the Gaussian filter window size. In range from 3 to 301, must be odd number.
Default is 31. Probably the most important parameter of the Dynamic Audio Normalizer
is the "window size" of the Gaussian smoothing filter. The filter's window size is
specified in frames, centered around the current frame. For the sake of simplicity,
this must be an odd number. Consequently, the default value of 31 takes into account
the current frame, as well as the 15 preceding frames and the 15 subsequent frames.
Using a larger window results in a stronger smoothing effect and thus in less gain
variation, i.e. slower gain adaptation. Conversely, using a smaller window results in
a weaker smoothing effect and thus in more gain variation, i.e. faster gain
adaptation. In other words, the more you increase this value, the more the Dynamic
Audio Normalizer will behave like a "traditional" normalization filter. On the
contrary, the more you decrease this value, the more the Dynamic Audio Normalizer will
behave like a dynamic range compressor.
peak, p
Set the target peak value. This specifies the highest permissible magnitude level for
the normalized audio input. This filter will try to approach the target peak magnitude
as closely as possible, but at the same time it also makes sure that the normalized
signal will never exceed the peak magnitude. A frame's maximum local gain factor is
imposed directly by the target peak magnitude. The default value is 0.95 and thus
leaves a headroom of 5%*. It is not recommended to go above this value.
maxgain, m
Set the maximum gain factor. In range from 1.0 to 100.0. Default is 10.0. The Dynamic
Audio Normalizer determines the maximum possible (local) gain factor for each input
frame, i.e. the maximum gain factor that does not result in clipping or distortion.
The maximum gain factor is determined by the frame's highest magnitude sample.
However, the Dynamic Audio Normalizer additionally bounds the frame's maximum gain
factor by a predetermined (global) maximum gain factor. This is done in order to avoid
excessive gain factors in "silent" or almost silent frames. By default, the maximum
gain factor is 10.0, For most inputs the default value should be sufficient and it
usually is not recommended to increase this value. Though, for input with an extremely
low overall volume level, it may be necessary to allow even higher gain factors. Note,
however, that the Dynamic Audio Normalizer does not simply apply a "hard" threshold
(i.e. cut off values above the threshold). Instead, a "sigmoid" threshold function
will be applied. This way, the gain factors will smoothly approach the threshold
value, but never exceed that value.
targetrms, r
Set the target RMS. In range from 0.0 to 1.0. Default is 0.0 - disabled. By default,
the Dynamic Audio Normalizer performs "peak" normalization. This means that the
maximum local gain factor for each frame is defined (only) by the frame's highest
magnitude sample. This way, the samples can be amplified as much as possible without
exceeding the maximum signal level, i.e. without clipping. Optionally, however, the
Dynamic Audio Normalizer can also take into account the frame's root mean square,
abbreviated RMS. In electrical engineering, the RMS is commonly used to determine the
power of a time-varying signal. It is therefore considered that the RMS is a better
approximation of the "perceived loudness" than just looking at the signal's peak
magnitude. Consequently, by adjusting all frames to a constant RMS value, a uniform
"perceived loudness" can be established. If a target RMS value has been specified, a
frame's local gain factor is defined as the factor that would result in exactly that
RMS value. Note, however, that the maximum local gain factor is still restricted by
the frame's highest magnitude sample, in order to prevent clipping.
coupling, n
Enable channels coupling. By default is enabled. By default, the Dynamic Audio
Normalizer will amplify all channels by the same amount. This means the same gain
factor will be applied to all channels, i.e. the maximum possible gain factor is
determined by the "loudest" channel. However, in some recordings, it may happen that
the volume of the different channels is uneven, e.g. one channel may be "quieter" than
the other one(s). In this case, this option can be used to disable the channel
coupling. This way, the gain factor will be determined independently for each channel,
depending only on the individual channel's highest magnitude sample. This allows for
harmonizing the volume of the different channels.
correctdc, c
Enable DC bias correction. By default is disabled. An audio signal (in the time
domain) is a sequence of sample values. In the Dynamic Audio Normalizer these sample
values are represented in the -1.0 to 1.0 range, regardless of the original input
format. Normally, the audio signal, or "waveform", should be centered around the zero
point. That means if we calculate the mean value of all samples in a file, or in a
single frame, then the result should be 0.0 or at least very close to that value. If,
however, there is a significant deviation of the mean value from 0.0, in either
positive or negative direction, this is referred to as a DC bias or DC offset. Since a
DC bias is clearly undesirable, the Dynamic Audio Normalizer provides optional DC bias
correction. With DC bias correction enabled, the Dynamic Audio Normalizer will
determine the mean value, or "DC correction" offset, of each input frame and subtract
that value from all of the frame's sample values which ensures those samples are
centered around 0.0 again. Also, in order to avoid "gaps" at the frame boundaries, the
DC correction offset values will be interpolated smoothly between neighbouring frames.
altboundary, b
Enable alternative boundary mode. By default is disabled. The Dynamic Audio
Normalizer takes into account a certain neighbourhood around each frame. This includes
the preceding frames as well as the subsequent frames. However, for the "boundary"
frames, located at the very beginning and at the very end of the audio file, not all
neighbouring frames are available. In particular, for the first few frames in the
audio file, the preceding frames are not known. And, similarly, for the last few
frames in the audio file, the subsequent frames are not known. Thus, the question
arises which gain factors should be assumed for the missing frames in the "boundary"
region. The Dynamic Audio Normalizer implements two modes to deal with this situation.
The default boundary mode assumes a gain factor of exactly 1.0 for the missing frames,
resulting in a smooth "fade in" and "fade out" at the beginning and at the end of the
input, respectively.
compress, s
Set the compress factor. In range from 0.0 to 30.0. Default is 0.0. By default, the
Dynamic Audio Normalizer does not apply "traditional" compression. This means that
signal peaks will not be pruned and thus the full dynamic range will be retained
within each local neighbourhood. However, in some cases it may be desirable to combine
the Dynamic Audio Normalizer's normalization algorithm with a more "traditional"
compression. For this purpose, the Dynamic Audio Normalizer provides an optional
compression (thresholding) function. If (and only if) the compression feature is
enabled, all input frames will be processed by a soft knee thresholding function prior
to the actual normalization process. Put simply, the thresholding function is going to
prune all samples whose magnitude exceeds a certain threshold value. However, the
Dynamic Audio Normalizer does not simply apply a fixed threshold value. Instead, the
threshold value will be adjusted for each individual frame. In general, smaller
parameters result in stronger compression, and vice versa. Values below 3.0 are not
recommended, because audible distortion may appear.
threshold, t
Set the target threshold value. This specifies the lowest permissible magnitude level
for the audio input which will be normalized. If input frame volume is above this
value frame will be normalized. Otherwise frame may not be normalized at all. The
default value is set to 0, which means all input frames will be normalized. This
option is mostly useful if digital noise is not wanted to be amplified.
channels, h
Specify which channels to filter, by default all available channels are filtered.
overlap, o
Specify overlap for frames. If set to 0 (default) no frame overlapping is done. Using
>0 and <1 values will make less conservative gain adjustments, like when framelen
option is set to smaller value, if framelen option value is compensated for non-zero
overlap then gain adjustments will be smoother across time compared to zero overlap
case.
curve, v
Specify the peak mapping curve expression which is going to be used when calculating
gain applied to frames. The max output frame gain will still be limited by other
options mentioned previously for this filter.
The expression can contain the following constants:
ch current channel number
sn current sample number
nb_channels
number of channels
t timestamp expressed in seconds
sr sample rate
p current frame peak value
Commands
This filter supports the all above options as commands.
earwax
Make audio easier to listen to on headphones.
This filter adds `cues' to 44.1kHz stereo (i.e. audio CD format) audio so that when
listened to on headphones the stereo image is moved from inside your head (standard for
headphones) to outside and in front of the listener (standard for speakers).
Ported from SoX.
equalizer
Apply a two-pole peaking equalisation (EQ) filter. With this filter, the signal-level at
and around a selected frequency can be increased or decreased, whilst (unlike bandpass and
bandreject filters) that at all other frequencies is unchanged.
In order to produce complex equalisation curves, this filter can be given several times,
each with a different central frequency.
The filter accepts the following options:
frequency, f
Set the filter's central frequency in Hz.
width_type, t
Set method to specify band-width of filter.
h Hz
q Q-Factor
o octave
s slope
k kHz
width, w
Specify the band-width of a filter in width_type units.
gain, g
Set the required gain or attenuation in dB. Beware of clipping when using a positive
gain.
mix, m
How much to use filtered signal in output. Default is 1. Range is between 0 and 1.
channels, c
Specify which channels to filter, by default all available are filtered.
normalize, n
Normalize biquad coefficients, by default is disabled. Enabling it will normalize
magnitude response at DC to 0dB.
transform, a
Set transform type of IIR filter.
di
dii
tdi
tdii
latt
svf
zdf
precision, r
Set precision of filtering.
auto
Pick automatic sample format depending on surround filters.
s16 Always use signed 16-bit.
s32 Always use signed 32-bit.
f32 Always use float 32-bit.
f64 Always use float 64-bit.
block_size, b
Set block size used for reverse IIR processing. If this value is set to high enough
value (higher than impulse response length truncated when reaches near zero values)
filtering will become linear phase otherwise if not big enough it will just produce
nasty artifacts.
Note that filter delay will be exactly this many samples when set to non-zero value.
Examples
• Attenuate 10 dB at 1000 Hz, with a bandwidth of 200 Hz:
equalizer=f=1000:t=h:width=200:g=-10
• Apply 2 dB gain at 1000 Hz with Q 1 and attenuate 5 dB at 100 Hz with Q 2:
equalizer=f=1000:t=q:w=1:g=2,equalizer=f=100:t=q:w=2:g=-5
Commands
This filter supports the following commands:
frequency, f
Change equalizer frequency. Syntax for the command is : "frequency"
width_type, t
Change equalizer width_type. Syntax for the command is : "width_type"
width, w
Change equalizer width. Syntax for the command is : "width"
gain, g
Change equalizer gain. Syntax for the command is : "gain"
mix, m
Change equalizer mix. Syntax for the command is : "mix"
extrastereo
Linearly increases the difference between left and right channels which adds some sort of
"live" effect to playback.
The filter accepts the following options:
m Sets the difference coefficient (default: 2.5). 0.0 means mono sound (average of both
channels), with 1.0 sound will be unchanged, with -1.0 left and right channels will be
swapped.
c Enable clipping. By default is enabled.
Commands
This filter supports the all above options as commands.
firequalizer
Apply FIR Equalization using arbitrary frequency response.
The filter accepts the following option:
gain
Set gain curve equation (in dB). The expression can contain variables:
f the evaluated frequency
sr sample rate
ch channel number, set to 0 when multichannels evaluation is disabled
chid
channel id, see libavutil/channel_layout.h, set to the first channel id when
multichannels evaluation is disabled
chs number of channels
chlayout
channel_layout, see libavutil/channel_layout.h
and functions:
gain_interpolate(f)
interpolate gain on frequency f based on gain_entry
cubic_interpolate(f)
same as gain_interpolate, but smoother
This option is also available as command. Default is gain_interpolate(f).
gain_entry
Set gain entry for gain_interpolate function. The expression can contain functions:
entry(f, g)
store gain entry at frequency f with value g
This option is also available as command.
delay
Set filter delay in seconds. Higher value means more accurate. Default is 0.01.
accuracy
Set filter accuracy in Hz. Lower value means more accurate. Default is 5.
wfunc
Set window function. Acceptable values are:
rectangular
rectangular window, useful when gain curve is already smooth
hann
hann window (default)
hamming
hamming window
blackman
blackman window
nuttall3
3-terms continuous 1st derivative nuttall window
mnuttall3
minimum 3-terms discontinuous nuttall window
nuttall
4-terms continuous 1st derivative nuttall window
bnuttall
minimum 4-terms discontinuous nuttall (blackman-nuttall) window
bharris
blackman-harris window
tukey
tukey window
fixed
If enabled, use fixed number of audio samples. This improves speed when filtering with
large delay. Default is disabled.
multi
Enable multichannels evaluation on gain. Default is disabled.
zero_phase
Enable zero phase mode by subtracting timestamp to compensate delay. Default is
disabled.
scale
Set scale used by gain. Acceptable values are:
linlin
linear frequency, linear gain
linlog
linear frequency, logarithmic (in dB) gain (default)
loglin
logarithmic (in octave scale where 20 Hz is 0) frequency, linear gain
loglog
logarithmic frequency, logarithmic gain
dumpfile
Set file for dumping, suitable for gnuplot.
dumpscale
Set scale for dumpfile. Acceptable values are same with scale option. Default is
linlog.
fft2
Enable 2-channel convolution using complex FFT. This improves speed significantly.
Default is disabled.
min_phase
Enable minimum phase impulse response. Default is disabled.
Examples
• lowpass at 1000 Hz:
firequalizer=gain='if(lt(f,1000), 0, -INF)'
• lowpass at 1000 Hz with gain_entry:
firequalizer=gain_entry='entry(1000,0); entry(1001, -INF)'
• custom equalization:
firequalizer=gain_entry='entry(100,0); entry(400, -4); entry(1000, -6); entry(2000, 0)'
• higher delay with zero phase to compensate delay:
firequalizer=delay=0.1:fixed=on:zero_phase=on
• lowpass on left channel, highpass on right channel:
firequalizer=gain='if(eq(chid,1), gain_interpolate(f), if(eq(chid,2), gain_interpolate(1e6+f), 0))'
:gain_entry='entry(1000, 0); entry(1001,-INF); entry(1e6+1000,0)':multi=on
flanger
Apply a flanging effect to the audio.
The filter accepts the following options:
delay
Set base delay in milliseconds. Range from 0 to 30. Default value is 0.
depth
Set added sweep delay in milliseconds. Range from 0 to 10. Default value is 2.
regen
Set percentage regeneration (delayed signal feedback). Range from -95 to 95. Default
value is 0.
width
Set percentage of delayed signal mixed with original. Range from 0 to 100. Default
value is 71.
speed
Set sweeps per second (Hz). Range from 0.1 to 10. Default value is 0.5.
shape
Set swept wave shape, can be triangular or sinusoidal. Default value is sinusoidal.
phase
Set swept wave percentage-shift for multi channel. Range from 0 to 100. Default value
is 25.
interp
Set delay-line interpolation, linear or quadratic. Default is linear.
haas
Apply Haas effect to audio.
Note that this makes most sense to apply on mono signals. With this filter applied to
mono signals it give some directionality and stretches its stereo image.
The filter accepts the following options:
level_in
Set input level. By default is 1, or 0dB
level_out
Set output level. By default is 1, or 0dB.
side_gain
Set gain applied to side part of signal. By default is 1.
middle_source
Set kind of middle source. Can be one of the following:
left
Pick left channel.
right
Pick right channel.
mid Pick middle part signal of stereo image.
side
Pick side part signal of stereo image.
middle_phase
Change middle phase. By default is disabled.
left_delay
Set left channel delay. By default is 2.05 milliseconds.
left_balance
Set left channel balance. By default is -1.
left_gain
Set left channel gain. By default is 1.
left_phase
Change left phase. By default is disabled.
right_delay
Set right channel delay. By defaults is 2.12 milliseconds.
right_balance
Set right channel balance. By default is 1.
right_gain
Set right channel gain. By default is 1.
right_phase
Change right phase. By default is enabled.
hdcd
Decodes High Definition Compatible Digital (HDCD) data. A 16-bit PCM stream with embedded
HDCD codes is expanded into a 20-bit PCM stream.
The filter supports the Peak Extend and Low-level Gain Adjustment features of HDCD, and
detects the Transient Filter flag.
ffmpeg -i HDCD16.flac -af hdcd OUT24.flac
When using the filter with wav, note the default encoding for wav is 16-bit, so the
resulting 20-bit stream will be truncated back to 16-bit. Use something like -acodec
pcm_s24le after the filter to get 24-bit PCM output.
ffmpeg -i HDCD16.wav -af hdcd OUT16.wav
ffmpeg -i HDCD16.wav -af hdcd -c:a pcm_s24le OUT24.wav
The filter accepts the following options:
disable_autoconvert
Disable any automatic format conversion or resampling in the filter graph.
process_stereo
Process the stereo channels together. If target_gain does not match between channels,
consider it invalid and use the last valid target_gain.
cdt_ms
Set the code detect timer period in ms.
force_pe
Always extend peaks above -3dBFS even if PE isn't signaled.
analyze_mode
Replace audio with a solid tone and adjust the amplitude to signal some specific
aspect of the decoding process. The output file can be loaded in an audio editor
alongside the original to aid analysis.
"analyze_mode=pe:force_pe=true" can be used to see all samples above the PE level.
Modes are:
0, off
Disabled
1, lle
Gain adjustment level at each sample
2, pe
Samples where peak extend occurs
3, cdt
Samples where the code detect timer is active
4, tgm
Samples where the target gain does not match between channels
headphone
Apply head-related transfer functions (HRTFs) to create virtual loudspeakers around the
user for binaural listening via headphones. The HRIRs are provided via additional
streams, for each channel one stereo input stream is needed.
The filter accepts the following options:
map Set mapping of input streams for convolution. The argument is a '|'-separated list of
channel names in order as they are given as additional stream inputs for filter. This
also specify number of input streams. Number of input streams must be not less than
number of channels in first stream plus one.
gain
Set gain applied to audio. Value is in dB. Default is 0.
type
Set processing type. Can be time or freq. time is processing audio in time domain
which is slow. freq is processing audio in frequency domain which is fast. Default
is freq.
lfe Set custom gain for LFE channels. Value is in dB. Default is 0.
size
Set size of frame in number of samples which will be processed at once. Default value
is 1024. Allowed range is from 1024 to 96000.
hrir
Set format of hrir stream. Default value is stereo. Alternative value is multich. If
value is set to stereo, number of additional streams should be greater or equal to
number of input channels in first input stream. Also each additional stream should
have stereo number of channels. If value is set to multich, number of additional
streams should be exactly one. Also number of input channels of additional stream
should be equal or greater than twice number of channels of first input stream.
Examples
• Full example using wav files as coefficients with amovie filters for 7.1 downmix, each
amovie filter use stereo file with IR coefficients as input. The files give
coefficients for each position of virtual loudspeaker:
ffmpeg -i input.wav
-filter_complex "amovie=azi_270_ele_0_DFC.wav[sr];amovie=azi_90_ele_0_DFC.wav[sl];amovie=azi_225_ele_0_DFC.wav[br];amovie=azi_135_ele_0_DFC.wav[bl];amovie=azi_0_ele_0_DFC.wav,asplit[fc][lfe];amovie=azi_35_ele_0_DFC.wav[fl];amovie=azi_325_ele_0_DFC.wav[fr];[0:a][fl][fr][fc][lfe][bl][br][sl][sr]headphone=FL|FR|FC|LFE|BL|BR|SL|SR"
output.wav
• Full example using wav files as coefficients with amovie filters for 7.1 downmix, but
now in multich hrir format.
ffmpeg -i input.wav -filter_complex "amovie=minp.wav[hrirs];[0:a][hrirs]headphone=map=FL|FR|FC|LFE|BL|BR|SL|SR:hrir=multich"
output.wav
highpass
Apply a high-pass filter with 3dB point frequency. The filter can be either single-pole,
or double-pole (the default). The filter roll off at 6dB per pole per octave (20dB per
pole per decade).
The filter accepts the following options:
frequency, f
Set frequency in Hz. Default is 3000.
poles, p
Set number of poles. Default is 2.
width_type, t
Set method to specify band-width of filter.
h Hz
q Q-Factor
o octave
s slope
k kHz
width, w
Specify the band-width of a filter in width_type units. Applies only to double-pole
filter. The default is 0.707q and gives a Butterworth response.
mix, m
How much to use filtered signal in output. Default is 1. Range is between 0 and 1.
channels, c
Specify which channels to filter, by default all available are filtered.
normalize, n
Normalize biquad coefficients, by default is disabled. Enabling it will normalize
magnitude response at DC to 0dB.
transform, a
Set transform type of IIR filter.
di
dii
tdi
tdii
latt
svf
zdf
precision, r
Set precision of filtering.
auto
Pick automatic sample format depending on surround filters.
s16 Always use signed 16-bit.
s32 Always use signed 32-bit.
f32 Always use float 32-bit.
f64 Always use float 64-bit.
block_size, b
Set block size used for reverse IIR processing. If this value is set to high enough
value (higher than impulse response length truncated when reaches near zero values)
filtering will become linear phase otherwise if not big enough it will just produce
nasty artifacts.
Note that filter delay will be exactly this many samples when set to non-zero value.
Commands
This filter supports the following commands:
frequency, f
Change highpass frequency. Syntax for the command is : "frequency"
width_type, t
Change highpass width_type. Syntax for the command is : "width_type"
width, w
Change highpass width. Syntax for the command is : "width"
mix, m
Change highpass mix. Syntax for the command is : "mix"
join
Join multiple input streams into one multi-channel stream.
It accepts the following parameters:
inputs
The number of input streams. It defaults to 2.
channel_layout
The desired output channel layout. It defaults to stereo.
map Map channels from inputs to output. The argument is a '|'-separated list of mappings,
each in the "input_idx.in_channel-out_channel" form. input_idx is the 0-based index of
the input stream. in_channel can be either the name of the input channel (e.g. FL for
front left) or its index in the specified input stream. out_channel is the name of the
output channel.
The filter will attempt to guess the mappings when they are not specified explicitly. It
does so by first trying to find an unused matching input channel and if that fails it
picks the first unused input channel.
Join 3 inputs (with properly set channel layouts):
ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex join=inputs=3 OUTPUT
Build a 5.1 output from 6 single-channel streams:
ffmpeg -i fl -i fr -i fc -i sl -i sr -i lfe -filter_complex
'join=inputs=6:channel_layout=5.1:map=0.0-FL|1.0-FR|2.0-FC|3.0-SL|4.0-SR|5.0-LFE'
out
ladspa
Load a LADSPA (Linux Audio Developer's Simple Plugin API) plugin.
To enable compilation of this filter you need to configure FFmpeg with "--enable-ladspa".
file, f
Specifies the name of LADSPA plugin library to load. If the environment variable
LADSPA_PATH is defined, the LADSPA plugin is searched in each one of the directories
specified by the colon separated list in LADSPA_PATH, otherwise in the standard LADSPA
paths, which are in this order: HOME/.ladspa/lib/, /usr/local/lib/ladspa/,
/usr/lib/ladspa/.
plugin, p
Specifies the plugin within the library. Some libraries contain only one plugin, but
others contain many of them. If this is not set filter will list all available plugins
within the specified library.
controls, c
Set the '|' separated list of controls which are zero or more floating point values
that determine the behavior of the loaded plugin (for example delay, threshold or
gain). Controls need to be defined using the following syntax:
c0=value0|c1=value1|c2=value2|..., where valuei is the value set on the i-th control.
Alternatively they can be also defined using the following syntax:
value0|value1|value2|..., where valuei is the value set on the i-th control. If
controls is set to "help", all available controls and their valid ranges are printed.
sample_rate, s
Specify the sample rate, default to 44100. Only used if plugin have zero inputs.
nb_samples, n
Set the number of samples per channel per each output frame, default is 1024. Only
used if plugin have zero inputs.
duration, d
Set the minimum duration of the sourced audio. See the Time duration section in the
ffmpeg-utils(1) manual for the accepted syntax. Note that the resulting duration may
be greater than the specified duration, as the generated audio is always cut at the
end of a complete frame. If not specified, or the expressed duration is negative, the
audio is supposed to be generated forever. Only used if plugin have zero inputs.
latency, l
Enable latency compensation, by default is disabled. Only used if plugin have inputs.
Examples
• List all available plugins within amp (LADSPA example plugin) library:
ladspa=file=amp
• List all available controls and their valid ranges for "vcf_notch" plugin from "VCF"
library:
ladspa=f=vcf:p=vcf_notch:c=help
• Simulate low quality audio equipment using "Computer Music Toolkit" (CMT) plugin
library:
ladspa=file=cmt:plugin=lofi:controls=c0=22|c1=12|c2=12
• Add reverberation to the audio using TAP-plugins (Tom's Audio Processing plugins):
ladspa=file=tap_reverb:tap_reverb
• Generate white noise, with 0.2 amplitude:
ladspa=file=cmt:noise_source_white:c=c0=.2
• Generate 20 bpm clicks using plugin "C* Click - Metronome" from the "C* Audio Plugin
Suite" (CAPS) library:
ladspa=file=caps:Click:c=c1=20'
• Apply "C* Eq10X2 - Stereo 10-band equaliser" effect:
ladspa=caps:Eq10X2:c=c0=-48|c9=-24|c3=12|c4=2
• Increase volume by 20dB using fast lookahead limiter from Steve Harris "SWH Plugins"
collection:
ladspa=fast_lookahead_limiter_1913:fastLookaheadLimiter:20|0|2
• Attenuate low frequencies using Multiband EQ from Steve Harris "SWH Plugins"
collection:
ladspa=mbeq_1197:mbeq:-24|-24|-24|0|0|0|0|0|0|0|0|0|0|0|0
• Reduce stereo image using "Narrower" from the "C* Audio Plugin Suite" (CAPS) library:
ladspa=caps:Narrower
• Another white noise, now using "C* Audio Plugin Suite" (CAPS) library:
ladspa=caps:White:.2
• Some fractal noise, using "C* Audio Plugin Suite" (CAPS) library:
ladspa=caps:Fractal:c=c1=1
• Dynamic volume normalization using "VLevel" plugin:
ladspa=vlevel-ladspa:vlevel_mono
Commands
This filter supports the following commands:
cN Modify the N-th control value.
If the specified value is not valid, it is ignored and prior one is kept.
loudnorm
EBU R128 loudness normalization. Includes both dynamic and linear normalization modes.
Support for both single pass (livestreams, files) and double pass (files) modes. This
algorithm can target IL, LRA, and maximum true peak. In dynamic mode, to accurately detect
true peaks, the audio stream will be upsampled to 192 kHz. Use the "-ar" option or
"aresample" filter to explicitly set an output sample rate.
The filter accepts the following options:
I, i
Set integrated loudness target. Range is -70.0 - -5.0. Default value is -24.0.
LRA, lra
Set loudness range target. Range is 1.0 - 50.0. Default value is 7.0.
TP, tp
Set maximum true peak. Range is -9.0 - +0.0. Default value is -2.0.
measured_I, measured_i
Measured IL of input file. Range is -99.0 - +0.0.
measured_LRA, measured_lra
Measured LRA of input file. Range is 0.0 - 99.0.
measured_TP, measured_tp
Measured true peak of input file. Range is -99.0 - +99.0.
measured_thresh
Measured threshold of input file. Range is -99.0 - +0.0.
offset
Set offset gain. Gain is applied before the true-peak limiter. Range is -99.0 -
+99.0. Default is +0.0.
linear
Normalize by linearly scaling the source audio. "measured_I", "measured_LRA",
"measured_TP", and "measured_thresh" must all be specified. Target LRA shouldn't be
lower than source LRA and the change in integrated loudness shouldn't result in a true
peak which exceeds the target TP. If any of these conditions aren't met, normalization
mode will revert to dynamic. Options are "true" or "false". Default is "true".
dual_mono
Treat mono input files as "dual-mono". If a mono file is intended for playback on a
stereo system, its EBU R128 measurement will be perceptually incorrect. If set to
"true", this option will compensate for this effect. Multi-channel input files are
not affected by this option. Options are true or false. Default is false.
print_format
Set print format for stats. Options are summary, json, or none. Default value is
none.
lowpass
Apply a low-pass filter with 3dB point frequency. The filter can be either single-pole or
double-pole (the default). The filter roll off at 6dB per pole per octave (20dB per pole
per decade).
The filter accepts the following options:
frequency, f
Set frequency in Hz. Default is 500.
poles, p
Set number of poles. Default is 2.
width_type, t
Set method to specify band-width of filter.
h Hz
q Q-Factor
o octave
s slope
k kHz
width, w
Specify the band-width of a filter in width_type units. Applies only to double-pole
filter. The default is 0.707q and gives a Butterworth response.
mix, m
How much to use filtered signal in output. Default is 1. Range is between 0 and 1.
channels, c
Specify which channels to filter, by default all available are filtered.
normalize, n
Normalize biquad coefficients, by default is disabled. Enabling it will normalize
magnitude response at DC to 0dB.
transform, a
Set transform type of IIR filter.
di
dii
tdi
tdii
latt
svf
zdf
precision, r
Set precision of filtering.
auto
Pick automatic sample format depending on surround filters.
s16 Always use signed 16-bit.
s32 Always use signed 32-bit.
f32 Always use float 32-bit.
f64 Always use float 64-bit.
block_size, b
Set block size used for reverse IIR processing. If this value is set to high enough
value (higher than impulse response length truncated when reaches near zero values)
filtering will become linear phase otherwise if not big enough it will just produce
nasty artifacts.
Note that filter delay will be exactly this many samples when set to non-zero value.
Examples
• Lowpass only LFE channel, it LFE is not present it does nothing:
lowpass=c=LFE
Commands
This filter supports the following commands:
frequency, f
Change lowpass frequency. Syntax for the command is : "frequency"
width_type, t
Change lowpass width_type. Syntax for the command is : "width_type"
width, w
Change lowpass width. Syntax for the command is : "width"
mix, m
Change lowpass mix. Syntax for the command is : "mix"
lv2
Load a LV2 (LADSPA Version 2) plugin.
To enable compilation of this filter you need to configure FFmpeg with "--enable-lv2".
plugin, p
Specifies the plugin URI. You may need to escape ':'.
controls, c
Set the '|' separated list of controls which are zero or more floating point values
that determine the behavior of the loaded plugin (for example delay, threshold or
gain). If controls is set to "help", all available controls and their valid ranges
are printed.
sample_rate, s
Specify the sample rate, default to 44100. Only used if plugin have zero inputs.
nb_samples, n
Set the number of samples per channel per each output frame, default is 1024. Only
used if plugin have zero inputs.
duration, d
Set the minimum duration of the sourced audio. See the Time duration section in the
ffmpeg-utils(1) manual for the accepted syntax. Note that the resulting duration may
be greater than the specified duration, as the generated audio is always cut at the
end of a complete frame. If not specified, or the expressed duration is negative, the
audio is supposed to be generated forever. Only used if plugin have zero inputs.
Examples
• Apply bass enhancer plugin from Calf:
lv2=p=http\\\\://calf.sourceforge.net/plugins/BassEnhancer:c=amount=2
• Apply vinyl plugin from Calf:
lv2=p=http\\\\://calf.sourceforge.net/plugins/Vinyl:c=drone=0.2|aging=0.5
• Apply bit crusher plugin from ArtyFX:
lv2=p=http\\\\://www.openavproductions.com/artyfx#bitta:c=crush=0.3
Commands
This filter supports all options that are exported by plugin as commands.
mcompand
Multiband Compress or expand the audio's dynamic range.
The input audio is divided into bands using 4th order Linkwitz-Riley IIRs. This is akin
to the crossover of a loudspeaker, and results in flat frequency response when absent
compander action.
It accepts the following parameters:
args
This option syntax is: attack,decay,[attack,decay..] soft-knee points
crossover_frequency [delay [initial_volume [gain]]] | attack,decay ... For
explanation of each item refer to compand filter documentation.
pan
Mix channels with specific gain levels. The filter accepts the output channel layout
followed by a set of channels definitions.
This filter is also designed to efficiently remap the channels of an audio stream.
The filter accepts parameters of the form: "l|outdef|outdef|..."
l output channel layout or number of channels
outdef
output channel specification, of the form:
"out_name=[gain*]in_name[(+-)[gain*]in_name...]"
out_name
output channel to define, either a channel name (FL, FR, etc.) or a channel number
(c0, c1, etc.)
gain
multiplicative coefficient for the channel, 1 leaving the volume unchanged
in_name
input channel to use, see out_name for details; it is not possible to mix named and
numbered input channels
If the `=' in a channel specification is replaced by `<', then the gains for that
specification will be renormalized so that the total is 1, thus avoiding clipping noise.
Mixing examples
For example, if you want to down-mix from stereo to mono, but with a bigger factor for the
left channel:
pan=1c|c0=0.9*c0+0.1*c1
A customized down-mix to stereo that works automatically for 3-, 4-, 5- and 7-channels
surround:
pan=stereo| FL < FL + 0.5*FC + 0.6*BL + 0.6*SL | FR < FR + 0.5*FC + 0.6*BR + 0.6*SR
Note that ffmpeg integrates a default down-mix (and up-mix) system that should be
preferred (see "-ac" option) unless you have very specific needs.
Remapping examples
The channel remapping will be effective if, and only if:
*<gain coefficients are zeroes or ones,>
*<only one input per channel output,>
If all these conditions are satisfied, the filter will notify the user ("Pure channel
mapping detected"), and use an optimized and lossless method to do the remapping.
For example, if you have a 5.1 source and want a stereo audio stream by dropping the extra
channels:
pan="stereo| c0=FL | c1=FR"
Given the same source, you can also switch front left and front right channels and keep
the input channel layout:
pan="5.1| c0=c1 | c1=c0 | c2=c2 | c3=c3 | c4=c4 | c5=c5"
If the input is a stereo audio stream, you can mute the front left channel (and still keep
the stereo channel layout) with:
pan="stereo|c1=c1"
Still with a stereo audio stream input, you can copy the right channel in both front left
and right:
pan="stereo| c0=FR | c1=FR"
replaygain
ReplayGain scanner filter. This filter takes an audio stream as an input and outputs it
unchanged. At end of filtering it displays "track_gain" and "track_peak".
The filter accepts the following exported read-only options:
track_gain
Exported track gain in dB at end of stream.
track_peak
Exported track peak at end of stream.
resample
Convert the audio sample format, sample rate and channel layout. It is not meant to be
used directly.
rubberband
Apply time-stretching and pitch-shifting with librubberband.
To enable compilation of this filter, you need to configure FFmpeg with
"--enable-librubberband".
The filter accepts the following options:
tempo
Set tempo scale factor.
pitch
Set pitch scale factor.
transients
Set transients detector. Possible values are:
crisp
mixed
smooth
detector
Set detector. Possible values are:
compound
percussive
soft
phase
Set phase. Possible values are:
laminar
independent
window
Set processing window size. Possible values are:
standard
short
long
smoothing
Set smoothing. Possible values are:
off
on
formant
Enable formant preservation when shift pitching. Possible values are:
shifted
preserved
pitchq
Set pitch quality. Possible values are:
quality
speed
consistency
channels
Set channels. Possible values are:
apart
together
Commands
This filter supports the following commands:
tempo
Change filter tempo scale factor. Syntax for the command is : "tempo"
pitch
Change filter pitch scale factor. Syntax for the command is : "pitch"
sidechaincompress
This filter acts like normal compressor but has the ability to compress detected signal
using second input signal. It needs two input streams and returns one output stream.
First input stream will be processed depending on second stream signal. The filtered
signal then can be filtered with other filters in later stages of processing. See pan and
amerge filter.
The filter accepts the following options:
level_in
Set input gain. Default is 1. Range is between 0.015625 and 64.
mode
Set mode of compressor operation. Can be "upward" or "downward". Default is
"downward".
threshold
If a signal of second stream raises above this level it will affect the gain reduction
of first stream. By default is 0.125. Range is between 0.00097563 and 1.
ratio
Set a ratio about which the signal is reduced. 1:2 means that if the level raised 4dB
above the threshold, it will be only 2dB above after the reduction. Default is 2.
Range is between 1 and 20.
attack
Amount of milliseconds the signal has to rise above the threshold before gain
reduction starts. Default is 20. Range is between 0.01 and 2000.
release
Amount of milliseconds the signal has to fall below the threshold before reduction is
decreased again. Default is 250. Range is between 0.01 and 9000.
makeup
Set the amount by how much signal will be amplified after processing. Default is 1.
Range is from 1 to 64.
knee
Curve the sharp knee around the threshold to enter gain reduction more softly.
Default is 2.82843. Range is between 1 and 8.
link
Choose if the "average" level between all channels of side-chain stream or the
louder("maximum") channel of side-chain stream affects the reduction. Default is
"average".
detection
Should the exact signal be taken in case of "peak" or an RMS one in case of "rms".
Default is "rms" which is mainly smoother.
level_sc
Set sidechain gain. Default is 1. Range is between 0.015625 and 64.
mix How much to use compressed signal in output. Default is 1. Range is between 0 and 1.
Commands
This filter supports the all above options as commands.
Examples
• Full ffmpeg example taking 2 audio inputs, 1st input to be compressed depending on the
signal of 2nd input and later compressed signal to be merged with 2nd input:
ffmpeg -i main.flac -i sidechain.flac -filter_complex "[1:a]asplit=2[sc][mix];[0:a][sc]sidechaincompress[compr];[compr][mix]amerge"
sidechaingate
A sidechain gate acts like a normal (wideband) gate but has the ability to filter the
detected signal before sending it to the gain reduction stage. Normally a gate uses the
full range signal to detect a level above the threshold. For example: If you cut all
lower frequencies from your sidechain signal the gate will decrease the volume of your
track only if not enough highs appear. With this technique you are able to reduce the
resonation of a natural drum or remove "rumbling" of muted strokes from a heavily
distorted guitar. It needs two input streams and returns one output stream. First input
stream will be processed depending on second stream signal.
The filter accepts the following options:
level_in
Set input level before filtering. Default is 1. Allowed range is from 0.015625 to 64.
mode
Set the mode of operation. Can be "upward" or "downward". Default is "downward". If
set to "upward" mode, higher parts of signal will be amplified, expanding dynamic
range in upward direction. Otherwise, in case of "downward" lower parts of signal
will be reduced.
range
Set the level of gain reduction when the signal is below the threshold. Default is
0.06125. Allowed range is from 0 to 1. Setting this to 0 disables reduction and then
filter behaves like expander.
threshold
If a signal rises above this level the gain reduction is released. Default is 0.125.
Allowed range is from 0 to 1.
ratio
Set a ratio about which the signal is reduced. Default is 2. Allowed range is from 1
to 9000.
attack
Amount of milliseconds the signal has to rise above the threshold before gain
reduction stops. Default is 20 milliseconds. Allowed range is from 0.01 to 9000.
release
Amount of milliseconds the signal has to fall below the threshold before the reduction
is increased again. Default is 250 milliseconds. Allowed range is from 0.01 to 9000.
makeup
Set amount of amplification of signal after processing. Default is 1. Allowed range
is from 1 to 64.
knee
Curve the sharp knee around the threshold to enter gain reduction more softly.
Default is 2.828427125. Allowed range is from 1 to 8.
detection
Choose if exact signal should be taken for detection or an RMS like one. Default is
rms. Can be peak or rms.
link
Choose if the average level between all channels or the louder channel affects the
reduction. Default is average. Can be average or maximum.
level_sc
Set sidechain gain. Default is 1. Range is from 0.015625 to 64.
Commands
This filter supports the all above options as commands.
silencedetect
Detect silence in an audio stream.
This filter logs a message when it detects that the input audio volume is less or equal to
a noise tolerance value for a duration greater or equal to the minimum detected noise
duration.
The printed times and duration are expressed in seconds. The "lavfi.silence_start" or
"lavfi.silence_start.X" metadata key is set on the first frame whose timestamp equals or
exceeds the detection duration and it contains the timestamp of the first frame of the
silence.
The "lavfi.silence_duration" or "lavfi.silence_duration.X" and "lavfi.silence_end" or
"lavfi.silence_end.X" metadata keys are set on the first frame after the silence. If mono
is enabled, and each channel is evaluated separately, the ".X" suffixed keys are used, and
"X" corresponds to the channel number.
The filter accepts the following options:
noise, n
Set noise tolerance. Can be specified in dB (in case "dB" is appended to the specified
value) or amplitude ratio. Default is -60dB, or 0.001.
duration, d
Set silence duration until notification (default is 2 seconds). See the Time duration
section in the ffmpeg-utils(1) manual for the accepted syntax.
mono, m
Process each channel separately, instead of combined. By default is disabled.
Examples
• Detect 5 seconds of silence with -50dB noise tolerance:
silencedetect=n=-50dB:d=5
• Complete example with ffmpeg to detect silence with 0.0001 noise tolerance in
silence.mp3:
ffmpeg -i silence.mp3 -af silencedetect=noise=0.0001 -f null -
silenceremove
Remove silence from the beginning, middle or end of the audio.
The filter accepts the following options:
start_periods
This value is used to indicate if audio should be trimmed at beginning of the audio. A
value of zero indicates no silence should be trimmed from the beginning. When
specifying a non-zero value, it trims audio up until it finds non-silence. Normally,
when trimming silence from beginning of audio the start_periods will be 1 but it can
be increased to higher values to trim all audio up to specific count of non-silence
periods. Default value is 0.
start_duration
Specify the amount of time that non-silence must be detected before it stops trimming
audio. By increasing the duration, bursts of noises can be treated as silence and
trimmed off. Default value is 0.
start_threshold
This indicates what sample value should be treated as silence. For digital audio, a
value of 0 may be fine but for audio recorded from analog, you may wish to increase
the value to account for background noise. Can be specified in dB (in case "dB" is
appended to the specified value) or amplitude ratio. Default value is 0.
start_silence
Specify max duration of silence at beginning that will be kept after trimming. Default
is 0, which is equal to trimming all samples detected as silence.
start_mode
Specify mode of detection of silence end at start of multi-channel audio. Can be any
or all. Default is any. With any, any sample from any channel that is detected as
non-silence will trigger end of silence trimming at start of audio stream. With all,
only if every sample from every channel is detected as non-silence will trigger end of
silence trimming at start of audio stream, limited usage.
stop_periods
Set the count for trimming silence from the end of audio. When specifying a positive
value, it trims audio after it finds specified silence period. To remove silence from
the middle of a file, specify a stop_periods that is negative. This value is then
treated as a positive value and is used to indicate the effect should restart
processing as specified by stop_periods, making it suitable for removing periods of
silence in the middle of the audio. Default value is 0.
stop_duration
Specify a duration of silence that must exist before audio is not copied any more. By
specifying a higher duration, silence that is wanted can be left in the audio.
Default value is 0.
stop_threshold
This is the same as start_threshold but for trimming silence from the end of audio.
Can be specified in dB (in case "dB" is appended to the specified value) or amplitude
ratio. Default value is 0.
stop_silence
Specify max duration of silence at end that will be kept after trimming. Default is 0,
which is equal to trimming all samples detected as silence.
stop_mode
Specify mode of detection of silence start after start of multi-channel audio. Can be
any or all. Default is all. With any, any sample from any channel that is detected as
silence will trigger start of silence trimming after start of audio stream, limited
usage. With all, only if every sample from every channel is detected as silence will
trigger start of silence trimming after start of audio stream.
detection
Set how is silence detected.
avg Mean of absolute values of samples in moving window.
rms Root squared mean of absolute values of samples in moving window.
peak
Maximum of absolute values of samples in moving window.
median
Median of absolute values of samples in moving window.
ptp Absolute of max peak to min peak difference of samples in moving window.
dev Standard deviation of values of samples in moving window.
Default value is "rms".
window
Set duration in number of seconds used to calculate size of window in number of
samples for detecting silence. Using 0 will effectively disable any windowing and use
only single sample per channel for silence detection. In that case it may be needed
to also set start_silence and/or stop_silence to nonzero values with also
start_duration and/or stop_duration to nonzero values. Default value is 0.02. Allowed
range is from 0 to 10.
timestamp
Set processing mode of every audio frame output timestamp.
write
Full timestamps rewrite, keep only the start time for the first output frame.
copy
Non-dropped frames are left with same timestamp as input audio frame.
Defaults value is "write".
Examples
• The following example shows how this filter can be used to start a recording that does
not contain the delay at the start which usually occurs between pressing the record
button and the start of the performance:
silenceremove=start_periods=1:start_duration=5:start_threshold=0.02
• Trim all silence encountered from beginning to end where there is more than 1 second
of silence in audio:
silenceremove=stop_periods=-1:stop_duration=1:stop_threshold=-90dB
• Trim all digital silence samples, using peak detection, from beginning to end where
there is more than 0 samples of digital silence in audio and digital silence is
detected in all channels at same positions in stream:
silenceremove=window=0:detection=peak:stop_mode=all:start_mode=all:stop_periods=-1:stop_threshold=0
• Trim every 2nd encountered silence period from beginning to end where there is more
than 1 second of silence per silence period in audio:
silenceremove=stop_periods=-2:stop_duration=1:stop_threshold=-90dB
• Similar as above, but keep maximum of 0.5 seconds of silence from each trimmed period:
silenceremove=stop_periods=-2:stop_duration=1:stop_threshold=-90dB:stop_silence=0.5
• Similar as above, but keep maximum of 1.5 seconds of silence from start of audio:
silenceremove=stop_periods=-2:stop_duration=1:stop_threshold=-90dB:stop_silence=0.5:start_periods=1:start_duration=1:start_silence=1.5:stop_threshold=-90dB
Commands
This filter supports some above options as commands.
sofalizer
SOFAlizer uses head-related transfer functions (HRTFs) to create virtual loudspeakers
around the user for binaural listening via headphones (audio formats up to 9 channels
supported). The HRTFs are stored in SOFA files (see <http://www.sofacoustics.org/> for a
database). SOFAlizer is developed at the Acoustics Research Institute (ARI) of the
Austrian Academy of Sciences.
To enable compilation of this filter you need to configure FFmpeg with
"--enable-libmysofa".
The filter accepts the following options:
sofa
Set the SOFA file used for rendering.
gain
Set gain applied to audio. Value is in dB. Default is 0.
rotation
Set rotation of virtual loudspeakers in deg. Default is 0.
elevation
Set elevation of virtual speakers in deg. Default is 0.
radius
Set distance in meters between loudspeakers and the listener with near-field HRTFs.
Default is 1.
type
Set processing type. Can be time or freq. time is processing audio in time domain
which is slow. freq is processing audio in frequency domain which is fast. Default
is freq.
speakers
Set custom positions of virtual loudspeakers. Syntax for this option is: <CH> <AZIM>
<ELEV>[|<CH> <AZIM> <ELEV>|...]. Each virtual loudspeaker is described with short
channel name following with azimuth and elevation in degrees. Each virtual
loudspeaker description is separated by '|'. For example to override front left and
front right channel positions use: 'speakers=FL 45 15|FR 345 15'. Descriptions with
unrecognised channel names are ignored.
lfegain
Set custom gain for LFE channels. Value is in dB. Default is 0.
framesize
Set custom frame size in number of samples. Default is 1024. Allowed range is from
1024 to 96000. Only used if option type is set to freq.
normalize
Should all IRs be normalized upon importing SOFA file. By default is enabled.
interpolate
Should nearest IRs be interpolated with neighbor IRs if exact position does not match.
By default is disabled.
minphase
Minphase all IRs upon loading of SOFA file. By default is disabled.
anglestep
Set neighbor search angle step. Only used if option interpolate is enabled.
radstep
Set neighbor search radius step. Only used if option interpolate is enabled.
Examples
• Using ClubFritz6 sofa file:
sofalizer=sofa=/path/to/ClubFritz6.sofa:type=freq:radius=1
• Using ClubFritz12 sofa file and bigger radius with small rotation:
sofalizer=sofa=/path/to/ClubFritz12.sofa:type=freq:radius=2:rotation=5
• Similar as above but with custom speaker positions for front left, front right, back
left and back right and also with custom gain:
"sofalizer=sofa=/path/to/ClubFritz6.sofa:type=freq:radius=2:speakers=FL 45|FR 315|BL 135|BR 225:gain=28"
speechnorm
Speech Normalizer.
This filter expands or compresses each half-cycle of audio samples (local set of samples
all above or all below zero and between two nearest zero crossings) depending on threshold
value, so audio reaches target peak value under conditions controlled by below options.
The filter accepts the following options:
peak, p
Set the expansion target peak value. This specifies the highest allowed absolute
amplitude level for the normalized audio input. Default value is 0.95. Allowed range
is from 0.0 to 1.0.
expansion, e
Set the maximum expansion factor. Allowed range is from 1.0 to 50.0. Default value is
2.0. This option controls maximum local half-cycle of samples expansion. The maximum
expansion would be such that local peak value reaches target peak value but never to
surpass it and that ratio between new and previous peak value does not surpass this
option value.
compression, c
Set the maximum compression factor. Allowed range is from 1.0 to 50.0. Default value
is 2.0. This option controls maximum local half-cycle of samples compression. This
option is used only if threshold option is set to value greater than 0.0, then in such
cases when local peak is lower or same as value set by threshold all samples belonging
to that peak's half-cycle will be compressed by current compression factor.
threshold, t
Set the threshold value. Default value is 0.0. Allowed range is from 0.0 to 1.0. This
option specifies which half-cycles of samples will be compressed and which will be
expanded. Any half-cycle samples with their local peak value below or same as this
option value will be compressed by current compression factor, otherwise, if greater
than threshold value they will be expanded with expansion factor so that it could
reach peak target value but never surpass it.
raise, r
Set the expansion raising amount per each half-cycle of samples. Default value is
0.001. Allowed range is from 0.0 to 1.0. This controls how fast expansion factor is
raised per each new half-cycle until it reaches expansion value. Setting this options
too high may lead to distortions.
fall, f
Set the compression raising amount per each half-cycle of samples. Default value is
0.001. Allowed range is from 0.0 to 1.0. This controls how fast compression factor is
raised per each new half-cycle until it reaches compression value.
channels, h
Specify which channels to filter, by default all available channels are filtered.
invert, i
Enable inverted filtering, by default is disabled. This inverts interpretation of
threshold option. When enabled any half-cycle of samples with their local peak value
below or same as threshold option will be expanded otherwise it will be compressed.
link, l
Link channels when calculating gain applied to each filtered channel sample, by
default is disabled. When disabled each filtered channel gain calculation is
independent, otherwise when this option is enabled the minimum of all possible gains
for each filtered channel is used.
rms, m
Set the expansion target RMS value. This specifies the highest allowed RMS level for
the normalized audio input. Default value is 0.0, thus disabled. Allowed range is from
0.0 to 1.0.
Commands
This filter supports the all above options as commands.
Examples
• Weak and slow amplification:
speechnorm=e=3:r=0.00001:l=1
• Moderate and slow amplification:
speechnorm=e=6.25:r=0.00001:l=1
• Strong and fast amplification:
speechnorm=e=12.5:r=0.0001:l=1
• Very strong and fast amplification:
speechnorm=e=25:r=0.0001:l=1
• Extreme and fast amplification:
speechnorm=e=50:r=0.0001:l=1
stereotools
This filter has some handy utilities to manage stereo signals, for converting M/S stereo
recordings to L/R signal while having control over the parameters or spreading the stereo
image of master track.
The filter accepts the following options:
level_in
Set input level before filtering for both channels. Defaults is 1. Allowed range is
from 0.015625 to 64.
level_out
Set output level after filtering for both channels. Defaults is 1. Allowed range is
from 0.015625 to 64.
balance_in
Set input balance between both channels. Default is 0. Allowed range is from -1 to 1.
balance_out
Set output balance between both channels. Default is 0. Allowed range is from -1 to
1.
softclip
Enable softclipping. Results in analog distortion instead of harsh digital 0dB
clipping. Disabled by default.
mutel
Mute the left channel. Disabled by default.
muter
Mute the right channel. Disabled by default.
phasel
Change the phase of the left channel. Disabled by default.
phaser
Change the phase of the right channel. Disabled by default.
mode
Set stereo mode. Available values are:
lr>lr
Left/Right to Left/Right, this is default.
lr>ms
Left/Right to Mid/Side.
ms>lr
Mid/Side to Left/Right.
lr>ll
Left/Right to Left/Left.
lr>rr
Left/Right to Right/Right.
lr>l+r
Left/Right to Left + Right.
lr>rl
Left/Right to Right/Left.
ms>ll
Mid/Side to Left/Left.
ms>rr
Mid/Side to Right/Right.
ms>rl
Mid/Side to Right/Left.
lr>l-r
Left/Right to Left - Right.
slev
Set level of side signal. Default is 1. Allowed range is from 0.015625 to 64.
sbal
Set balance of side signal. Default is 0. Allowed range is from -1 to 1.
mlev
Set level of the middle signal. Default is 1. Allowed range is from 0.015625 to 64.
mpan
Set middle signal pan. Default is 0. Allowed range is from -1 to 1.
base
Set stereo base between mono and inversed channels. Default is 0. Allowed range is
from -1 to 1.
delay
Set delay in milliseconds how much to delay left from right channel and vice versa.
Default is 0. Allowed range is from -20 to 20.
sclevel
Set S/C level. Default is 1. Allowed range is from 1 to 100.
phase
Set the stereo phase in degrees. Default is 0. Allowed range is from 0 to 360.
bmode_in, bmode_out
Set balance mode for balance_in/balance_out option.
Can be one of the following:
balance
Classic balance mode. Attenuate one channel at time. Gain is raised up to 1.
amplitude
Similar as classic mode above but gain is raised up to 2.
power
Equal power distribution, from -6dB to +6dB range.
Commands
This filter supports the all above options as commands.
Examples
• Apply karaoke like effect:
stereotools=mlev=0.015625
• Convert M/S signal to L/R:
"stereotools=mode=ms>lr"
stereowiden
This filter enhance the stereo effect by suppressing signal common to both channels and by
delaying the signal of left into right and vice versa, thereby widening the stereo effect.
The filter accepts the following options:
delay
Time in milliseconds of the delay of left signal into right and vice versa. Default
is 20 milliseconds.
feedback
Amount of gain in delayed signal into right and vice versa. Gives a delay effect of
left signal in right output and vice versa which gives widening effect. Default is
0.3.
crossfeed
Cross feed of left into right with inverted phase. This helps in suppressing the mono.
If the value is 1 it will cancel all the signal common to both channels. Default is
0.3.
drymix
Set level of input signal of original channel. Default is 0.8.
Commands
This filter supports the all above options except "delay" as commands.
superequalizer
Apply 18 band equalizer.
The filter accepts the following options:
1b Set 65Hz band gain.
2b Set 92Hz band gain.
3b Set 131Hz band gain.
4b Set 185Hz band gain.
5b Set 262Hz band gain.
6b Set 370Hz band gain.
7b Set 523Hz band gain.
8b Set 740Hz band gain.
9b Set 1047Hz band gain.
10b Set 1480Hz band gain.
11b Set 2093Hz band gain.
12b Set 2960Hz band gain.
13b Set 4186Hz band gain.
14b Set 5920Hz band gain.
15b Set 8372Hz band gain.
16b Set 11840Hz band gain.
17b Set 16744Hz band gain.
18b Set 20000Hz band gain.
surround
Apply audio surround upmix filter.
This filter allows to produce multichannel output from audio stream.
The filter accepts the following options:
chl_out
Set output channel layout. By default, this is 5.1.
See the Channel Layout section in the ffmpeg-utils(1) manual for the required syntax.
chl_in
Set input channel layout. By default, this is stereo.
See the Channel Layout section in the ffmpeg-utils(1) manual for the required syntax.
level_in
Set input volume level. By default, this is 1.
level_out
Set output volume level. By default, this is 1.
lfe Enable LFE channel output if output channel layout has it. By default, this is
enabled.
lfe_low
Set LFE low cut off frequency. By default, this is 128 Hz.
lfe_high
Set LFE high cut off frequency. By default, this is 256 Hz.
lfe_mode
Set LFE mode, can be add or sub. Default is add. In add mode, LFE channel is created
from input audio and added to output. In sub mode, LFE channel is created from input
audio and added to output but also all non-LFE output channels are subtracted with
output LFE channel.
smooth
Set temporal smoothness strength, used to gradually change factors when transforming
stereo sound in time. Allowed range is from 0.0 to 1.0. Useful to improve output
quality with focus option values greater than 0.0. Default is 0.0. Only values inside
this range and without edges are effective.
angle
Set angle of stereo surround transform, Allowed range is from 0 to 360. Default is
90.
focus
Set focus of stereo surround transform, Allowed range is from -1 to 1. Default is 0.
fc_in
Set front center input volume. By default, this is 1.
fc_out
Set front center output volume. By default, this is 1.
fl_in
Set front left input volume. By default, this is 1.
fl_out
Set front left output volume. By default, this is 1.
fr_in
Set front right input volume. By default, this is 1.
fr_out
Set front right output volume. By default, this is 1.
sl_in
Set side left input volume. By default, this is 1.
sl_out
Set side left output volume. By default, this is 1.
sr_in
Set side right input volume. By default, this is 1.
sr_out
Set side right output volume. By default, this is 1.
bl_in
Set back left input volume. By default, this is 1.
bl_out
Set back left output volume. By default, this is 1.
br_in
Set back right input volume. By default, this is 1.
br_out
Set back right output volume. By default, this is 1.
bc_in
Set back center input volume. By default, this is 1.
bc_out
Set back center output volume. By default, this is 1.
lfe_in
Set LFE input volume. By default, this is 1.
lfe_out
Set LFE output volume. By default, this is 1.
allx
Set spread usage of stereo image across X axis for all channels. Allowed range is
from -1 to 15. By default this value is negative -1, and thus unused.
ally
Set spread usage of stereo image across Y axis for all channels. Allowed range is
from -1 to 15. By default this value is negative -1, and thus unused.
fcx, flx, frx, blx, brx, slx, srx, bcx
Set spread usage of stereo image across X axis for each channel. Allowed range is
from 0.06 to 15. By default this value is 0.5.
fcy, fly, fry, bly, bry, sly, sry, bcy
Set spread usage of stereo image across Y axis for each channel. Allowed range is
from 0.06 to 15. By default this value is 0.5.
win_size
Set window size. Allowed range is from 1024 to 65536. Default size is 4096.
win_func
Set window function.
It accepts the following values:
rect
bartlett
hann, hanning
hamming
blackman
welch
flattop
bharris
bnuttall
bhann
sine
nuttall
lanczos
gauss
tukey
dolph
cauchy
parzen
poisson
bohman
kaiser
Default is "hann".
overlap
Set window overlap. If set to 1, the recommended overlap for selected window function
will be picked. Default is 0.5.
tiltshelf
Boost or cut the lower frequencies and cut or boost higher frequencies of the audio using
a two-pole shelving filter with a response similar to that of a standard hi-fi's tone-
controls. This is also known as shelving equalisation (EQ).
The filter accepts the following options:
gain, g
Give the gain at 0 Hz. Its useful range is about -20 (for a large cut) to +20 (for a
large boost). Beware of clipping when using a positive gain.
frequency, f
Set the filter's central frequency and so can be used to extend or reduce the
frequency range to be boosted or cut. The default value is 3000 Hz.
width_type, t
Set method to specify band-width of filter.
h Hz
q Q-Factor
o octave
s slope
k kHz
width, w
Determine how steep is the filter's shelf transition.
poles, p
Set number of poles. Default is 2.
mix, m
How much to use filtered signal in output. Default is 1. Range is between 0 and 1.
channels, c
Specify which channels to filter, by default all available are filtered.
normalize, n
Normalize biquad coefficients, by default is disabled. Enabling it will normalize
magnitude response at DC to 0dB.
transform, a
Set transform type of IIR filter.
di
dii
tdi
tdii
latt
svf
zdf
precision, r
Set precision of filtering.
auto
Pick automatic sample format depending on surround filters.
s16 Always use signed 16-bit.
s32 Always use signed 32-bit.
f32 Always use float 32-bit.
f64 Always use float 64-bit.
block_size, b
Set block size used for reverse IIR processing. If this value is set to high enough
value (higher than impulse response length truncated when reaches near zero values)
filtering will become linear phase otherwise if not big enough it will just produce
nasty artifacts.
Note that filter delay will be exactly this many samples when set to non-zero value.
Commands
This filter supports some options as commands.
treble, highshelf
Boost or cut treble (upper) frequencies of the audio using a two-pole shelving filter with
a response similar to that of a standard hi-fi's tone-controls. This is also known as
shelving equalisation (EQ).
The filter accepts the following options:
gain, g
Give the gain at whichever is the lower of ~22 kHz and the Nyquist frequency. Its
useful range is about -20 (for a large cut) to +20 (for a large boost). Beware of
clipping when using a positive gain.
frequency, f
Set the filter's central frequency and so can be used to extend or reduce the
frequency range to be boosted or cut. The default value is 3000 Hz.
width_type, t
Set method to specify band-width of filter.
h Hz
q Q-Factor
o octave
s slope
k kHz
width, w
Determine how steep is the filter's shelf transition.
poles, p
Set number of poles. Default is 2.
mix, m
How much to use filtered signal in output. Default is 1. Range is between 0 and 1.
channels, c
Specify which channels to filter, by default all available are filtered.
normalize, n
Normalize biquad coefficients, by default is disabled. Enabling it will normalize
magnitude response at DC to 0dB.
transform, a
Set transform type of IIR filter.
di
dii
tdi
tdii
latt
svf
zdf
precision, r
Set precision of filtering.
auto
Pick automatic sample format depending on surround filters.
s16 Always use signed 16-bit.
s32 Always use signed 32-bit.
f32 Always use float 32-bit.
f64 Always use float 64-bit.
block_size, b
Set block size used for reverse IIR processing. If this value is set to high enough
value (higher than impulse response length truncated when reaches near zero values)
filtering will become linear phase otherwise if not big enough it will just produce
nasty artifacts.
Note that filter delay will be exactly this many samples when set to non-zero value.
Commands
This filter supports the following commands:
frequency, f
Change treble frequency. Syntax for the command is : "frequency"
width_type, t
Change treble width_type. Syntax for the command is : "width_type"
width, w
Change treble width. Syntax for the command is : "width"
gain, g
Change treble gain. Syntax for the command is : "gain"
mix, m
Change treble mix. Syntax for the command is : "mix"
tremolo
Sinusoidal amplitude modulation.
The filter accepts the following options:
f Modulation frequency in Hertz. Modulation frequencies in the subharmonic range (20 Hz
or lower) will result in a tremolo effect. This filter may also be used as a ring
modulator by specifying a modulation frequency higher than 20 Hz. Range is 0.1 -
20000.0. Default value is 5.0 Hz.
d Depth of modulation as a percentage. Range is 0.0 - 1.0. Default value is 0.5.
vibrato
Sinusoidal phase modulation.
The filter accepts the following options:
f Modulation frequency in Hertz. Range is 0.1 - 20000.0. Default value is 5.0 Hz.
d Depth of modulation as a percentage. Range is 0.0 - 1.0. Default value is 0.5.
virtualbass
Apply audio Virtual Bass filter.
This filter accepts stereo input and produce stereo with LFE (2.1) channels output. The
newly produced LFE channel have enhanced virtual bass originally obtained from both stereo
channels. This filter outputs front left and front right channels unchanged as available
in stereo input.
The filter accepts the following options:
cutoff
Set the virtual bass cutoff frequency. Default value is 250 Hz. Allowed range is from
100 to 500 Hz.
strength
Set the virtual bass strength. Allowed range is from 0.5 to 3. Default value is 3.
volume
Adjust the input audio volume.
It accepts the following parameters:
volume
Set audio volume expression.
Output values are clipped to the maximum value.
The output audio volume is given by the relation:
<output_volume> = <volume> * <input_volume>
The default value for volume is "1.0".
precision
This parameter represents the mathematical precision.
It determines which input sample formats will be allowed, which affects the precision
of the volume scaling.
fixed
8-bit fixed-point; this limits input sample format to U8, S16, and S32.
float
32-bit floating-point; this limits input sample format to FLT. (default)
double
64-bit floating-point; this limits input sample format to DBL.
replaygain
Choose the behaviour on encountering ReplayGain side data in input frames.
drop
Remove ReplayGain side data, ignoring its contents (the default).
ignore
Ignore ReplayGain side data, but leave it in the frame.
track
Prefer the track gain, if present.
album
Prefer the album gain, if present.
replaygain_preamp
Pre-amplification gain in dB to apply to the selected replaygain gain.
Default value for replaygain_preamp is 0.0.
replaygain_noclip
Prevent clipping by limiting the gain applied.
Default value for replaygain_noclip is 1.
eval
Set when the volume expression is evaluated.
It accepts the following values:
once
only evaluate expression once during the filter initialization, or when the volume
command is sent
frame
evaluate expression for each incoming frame
Default value is once.
The volume expression can contain the following parameters.
n frame number (starting at zero)
nb_channels
number of channels
nb_consumed_samples
number of samples consumed by the filter
nb_samples
number of samples in the current frame
pos original frame position in the file; deprecated, do not use
pts frame PTS
sample_rate
sample rate
startpts
PTS at start of stream
startt
time at start of stream
t frame time
tb timestamp timebase
volume
last set volume value
Note that when eval is set to once only the sample_rate and tb variables are available,
all other variables will evaluate to NAN.
Commands
This filter supports the following commands:
volume
Modify the volume expression. The command accepts the same syntax of the
corresponding option.
If the specified expression is not valid, it is kept at its current value.
Examples
• Halve the input audio volume:
volume=volume=0.5
volume=volume=1/2
volume=volume=-6.0206dB
In all the above example the named key for volume can be omitted, for example like in:
volume=0.5
• Increase input audio power by 6 decibels using fixed-point precision:
volume=volume=6dB:precision=fixed
• Fade volume after time 10 with an annihilation period of 5 seconds:
volume='if(lt(t,10),1,max(1-(t-10)/5,0))':eval=frame
volumedetect
Detect the volume of the input video.
The filter has no parameters. It supports only 16-bit signed integer samples, so the input
will be converted when needed. Statistics about the volume will be printed in the log when
the input stream end is reached.
In particular it will show the mean volume (root mean square), maximum volume (on a per-
sample basis), and the beginning of a histogram of the registered volume values (from the
maximum value to a cumulated 1/1000 of the samples).
All volumes are in decibels relative to the maximum PCM value.
Examples
Here is an excerpt of the output:
[Parsed_volumedetect_0 0xa23120] mean_volume: -27 dB
[Parsed_volumedetect_0 0xa23120] max_volume: -4 dB
[Parsed_volumedetect_0 0xa23120] histogram_4db: 6
[Parsed_volumedetect_0 0xa23120] histogram_5db: 62
[Parsed_volumedetect_0 0xa23120] histogram_6db: 286
[Parsed_volumedetect_0 0xa23120] histogram_7db: 1042
[Parsed_volumedetect_0 0xa23120] histogram_8db: 2551
[Parsed_volumedetect_0 0xa23120] histogram_9db: 4609
[Parsed_volumedetect_0 0xa23120] histogram_10db: 8409
It means that:
• The mean square energy is approximately -27 dB, or 10^-2.7.
• The largest sample is at -4 dB, or more precisely between -4 dB and -5 dB.
• There are 6 samples at -4 dB, 62 at -5 dB, 286 at -6 dB, etc.
In other words, raising the volume by +4 dB does not cause any clipping, raising it by +5
dB causes clipping for 6 samples, etc.
AUDIO SOURCES
Below is a description of the currently available audio sources.
abuffer
Buffer audio frames, and make them available to the filter chain.
This source is mainly intended for a programmatic use, in particular through the interface
defined in libavfilter/buffersrc.h.
It accepts the following parameters:
time_base
The timebase which will be used for timestamps of submitted frames. It must be either
a floating-point number or in numerator/denominator form.
sample_rate
The sample rate of the incoming audio buffers.
sample_fmt
The sample format of the incoming audio buffers. Either a sample format name or its
corresponding integer representation from the enum AVSampleFormat in
libavutil/samplefmt.h
channel_layout
The channel layout of the incoming audio buffers. Either a channel layout name from
channel_layout_map in libavutil/channel_layout.c or its corresponding integer
representation from the AV_CH_LAYOUT_* macros in libavutil/channel_layout.h
channels
The number of channels of the incoming audio buffers. If both channels and
channel_layout are specified, then they must be consistent.
Examples
abuffer=sample_rate=44100:sample_fmt=s16p:channel_layout=stereo
will instruct the source to accept planar 16bit signed stereo at 44100Hz. Since the
sample format with name "s16p" corresponds to the number 6 and the "stereo" channel layout
corresponds to the value 0x3, this is equivalent to:
abuffer=sample_rate=44100:sample_fmt=6:channel_layout=0x3
aevalsrc
Generate an audio signal specified by an expression.
This source accepts in input one or more expressions (one for each channel), which are
evaluated and used to generate a corresponding audio signal.
This source accepts the following options:
exprs
Set the '|'-separated expressions list for each separate channel. In case the
channel_layout option is not specified, the selected channel layout depends on the
number of provided expressions. Otherwise the last specified expression is applied to
the remaining output channels.
channel_layout, c
Set the channel layout. The number of channels in the specified layout must be equal
to the number of specified expressions.
duration, d
Set the minimum duration of the sourced audio. See the Time duration section in the
ffmpeg-utils(1) manual for the accepted syntax. Note that the resulting duration may
be greater than the specified duration, as the generated audio is always cut at the
end of a complete frame.
If not specified, or the expressed duration is negative, the audio is supposed to be
generated forever.
nb_samples, n
Set the number of samples per channel per each output frame, default to 1024.
sample_rate, s
Specify the sample rate, default to 44100.
Each expression in exprs can contain the following constants:
n number of the evaluated sample, starting from 0
t time of the evaluated sample expressed in seconds, starting from 0
s sample rate
Examples
• Generate silence:
aevalsrc=0
• Generate a sin signal with frequency of 440 Hz, set sample rate to 8000 Hz:
aevalsrc="sin(440*2*PI*t):s=8000"
• Generate a two channels signal, specify the channel layout (Front Center + Back
Center) explicitly:
aevalsrc="sin(420*2*PI*t)|cos(430*2*PI*t):c=FC|BC"
• Generate white noise:
aevalsrc="-2+random(0)"
• Generate an amplitude modulated signal:
aevalsrc="sin(10*2*PI*t)*sin(880*2*PI*t)"
• Generate 2.5 Hz binaural beats on a 360 Hz carrier:
aevalsrc="0.1*sin(2*PI*(360-2.5/2)*t) | 0.1*sin(2*PI*(360+2.5/2)*t)"
afdelaysrc
Generate a fractional delay FIR coefficients.
The resulting stream can be used with afir filter for filtering the audio signal.
The filter accepts the following options:
delay, d
Set the fractional delay. Default is 0.
sample_rate, r
Set the sample rate, default is 44100.
nb_samples, n
Set the number of samples per each frame. Default is 1024.
taps, t
Set the number of filter coefficients in output audio stream. Default value is 0.
channel_layout, c
Specifies the channel layout, and can be a string representing a channel layout. The
default value of channel_layout is "stereo".
afireqsrc
Generate a FIR equalizer coefficients.
The resulting stream can be used with afir filter for filtering the audio signal.
The filter accepts the following options:
preset, p
Set equalizer preset. Default preset is "flat".
Available presets are:
custom
flat
acoustic
bass
beats
classic
clear
deep bass
dubstep
electronic
hard-style
hip-hop
jazz
metal
movie
pop
r&b
rock
vocal booster
gains, g
Set custom gains for each band. Only used if the preset option is set to "custom".
Gains are separated by white spaces and each gain is set in dBFS. Default is "0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0".
bands, b
Set the custom bands from where custon equalizer gains are set. This must be in
strictly increasing order. Only used if the preset option is set to "custom". Bands
are separated by white spaces and each band represent frequency in Hz. Default is "25
40 63 100 160 250 400 630 1000 1600 2500 4000 6300 10000 16000 24000".
taps, t
Set number of filter coefficients in output audio stream. Default value is 4096.
sample_rate, r
Set sample rate of output audio stream, default is 44100.
nb_samples, n
Set number of samples per each frame in output audio stream. Default is 1024.
interp, i
Set interpolation method for FIR equalizer coefficients. Can be "linear" or "cubic".
phase, h
Set phase type of FIR filter. Can be "linear" or "min": minimum-phase. Default is
minimum-phase filter.
afirsrc
Generate a FIR coefficients using frequency sampling method.
The resulting stream can be used with afir filter for filtering the audio signal.
The filter accepts the following options:
taps, t
Set number of filter coefficients in output audio stream. Default value is 1025.
frequency, f
Set frequency points from where magnitude and phase are set. This must be in non
decreasing order, and first element must be 0, while last element must be 1. Elements
are separated by white spaces.
magnitude, m
Set magnitude value for every frequency point set by frequency. Number of values must
be same as number of frequency points. Values are separated by white spaces.
phase, p
Set phase value for every frequency point set by frequency. Number of values must be
same as number of frequency points. Values are separated by white spaces.
sample_rate, r
Set sample rate, default is 44100.
nb_samples, n
Set number of samples per each frame. Default is 1024.
win_func, w
Set window function. Default is blackman.
anullsrc
The null audio source, return unprocessed audio frames. It is mainly useful as a template
and to be employed in analysis / debugging tools, or as the source for filters which
ignore the input data (for example the sox synth filter).
This source accepts the following options:
channel_layout, cl
Specifies the channel layout, and can be either an integer or a string representing a
channel layout. The default value of channel_layout is "stereo".
Check the channel_layout_map definition in libavutil/channel_layout.c for the mapping
between strings and channel layout values.
sample_rate, r
Specifies the sample rate, and defaults to 44100.
nb_samples, n
Set the number of samples per requested frames.
duration, d
Set the duration of the sourced audio. See the Time duration section in the
ffmpeg-utils(1) manual for the accepted syntax.
If not specified, or the expressed duration is negative, the audio is supposed to be
generated forever.
Examples
• Set the sample rate to 48000 Hz and the channel layout to AV_CH_LAYOUT_MONO.
anullsrc=r=48000:cl=4
• Do the same operation with a more obvious syntax:
anullsrc=r=48000:cl=mono
All the parameters need to be explicitly defined.
flite
Synthesize a voice utterance using the libflite library.
To enable compilation of this filter you need to configure FFmpeg with
"--enable-libflite".
Note that versions of the flite library prior to 2.0 are not thread-safe.
The filter accepts the following options:
list_voices
If set to 1, list the names of the available voices and exit immediately. Default
value is 0.
nb_samples, n
Set the maximum number of samples per frame. Default value is 512.
textfile
Set the filename containing the text to speak.
text
Set the text to speak.
voice, v
Set the voice to use for the speech synthesis. Default value is "kal". See also the
list_voices option.
Examples
• Read from file speech.txt, and synthesize the text using the standard flite voice:
flite=textfile=speech.txt
• Read the specified text selecting the "slt" voice:
flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
• Input text to ffmpeg:
ffmpeg -f lavfi -i flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
• Make ffplay speak the specified text, using "flite" and the "lavfi" device:
ffplay -f lavfi flite=text='No more be grieved for which that thou hast done.'
For more information about libflite, check: <http://www.festvox.org/flite/>
anoisesrc
Generate a noise audio signal.
The filter accepts the following options:
sample_rate, r
Specify the sample rate. Default value is 48000 Hz.
amplitude, a
Specify the amplitude (0.0 - 1.0) of the generated audio stream. Default value is 1.0.
duration, d
Specify the duration of the generated audio stream. Not specifying this option results
in noise with an infinite length.
color, colour, c
Specify the color of noise. Available noise colors are white, pink, brown, blue,
violet and velvet. Default color is white.
seed, s
Specify a value used to seed the PRNG.
nb_samples, n
Set the number of samples per each output frame, default is 1024.
density
Set the density (0.0 - 1.0) for the velvet noise generator, default is 0.05.
Examples
• Generate 60 seconds of pink noise, with a 44.1 kHz sampling rate and an amplitude of
0.5:
anoisesrc=d=60:c=pink:r=44100:a=0.5
hilbert
Generate odd-tap Hilbert transform FIR coefficients.
The resulting stream can be used with afir filter for phase-shifting the signal by 90
degrees.
This is used in many matrix coding schemes and for analytic signal generation. The
process is often written as a multiplication by i (or j), the imaginary unit.
The filter accepts the following options:
sample_rate, s
Set sample rate, default is 44100.
taps, t
Set length of FIR filter, default is 22051.
nb_samples, n
Set number of samples per each frame.
win_func, w
Set window function to be used when generating FIR coefficients.
sinc
Generate a sinc kaiser-windowed low-pass, high-pass, band-pass, or band-reject FIR
coefficients.
The resulting stream can be used with afir filter for filtering the audio signal.
The filter accepts the following options:
sample_rate, r
Set sample rate, default is 44100.
nb_samples, n
Set number of samples per each frame. Default is 1024.
hp Set high-pass frequency. Default is 0.
lp Set low-pass frequency. Default is 0. If high-pass frequency is lower than low-pass
frequency and low-pass frequency is higher than 0 then filter will create band-pass
filter coefficients, otherwise band-reject filter coefficients.
phase
Set filter phase response. Default is 50. Allowed range is from 0 to 100.
beta
Set Kaiser window beta.
att Set stop-band attenuation. Default is 120dB, allowed range is from 40 to 180 dB.
round
Enable rounding, by default is disabled.
hptaps
Set number of taps for high-pass filter.
lptaps
Set number of taps for low-pass filter.
sine
Generate an audio signal made of a sine wave with amplitude 1/8.
The audio signal is bit-exact.
The filter accepts the following options:
frequency, f
Set the carrier frequency. Default is 440 Hz.
beep_factor, b
Enable a periodic beep every second with frequency beep_factor times the carrier
frequency. Default is 0, meaning the beep is disabled.
sample_rate, r
Specify the sample rate, default is 44100.
duration, d
Specify the duration of the generated audio stream.
samples_per_frame
Set the number of samples per output frame.
The expression can contain the following constants:
n The (sequential) number of the output audio frame, starting from 0.
pts The PTS (Presentation TimeStamp) of the output audio frame, expressed in TB units.
t The PTS of the output audio frame, expressed in seconds.
TB The timebase of the output audio frames.
Default is 1024.
Examples
• Generate a simple 440 Hz sine wave:
sine
• Generate a 220 Hz sine wave with a 880 Hz beep each second, for 5 seconds:
sine=220:4:d=5
sine=f=220:b=4:d=5
sine=frequency=220:beep_factor=4:duration=5
• Generate a 1 kHz sine wave following "1602,1601,1602,1601,1602" NTSC pattern:
sine=1000:samples_per_frame='st(0,mod(n,5)); 1602-not(not(eq(ld(0),1)+eq(ld(0),3)))'
AUDIO SINKS
Below is a description of the currently available audio sinks.
abuffersink
Buffer audio frames, and make them available to the end of filter chain.
This sink is mainly intended for programmatic use, in particular through the interface
defined in libavfilter/buffersink.h or the options system.
It accepts a pointer to an AVABufferSinkContext structure, which defines the incoming
buffers' formats, to be passed as the opaque parameter to "avfilter_init_filter" for
initialization.
anullsink
Null audio sink; do absolutely nothing with the input audio. It is mainly useful as a
template and for use in analysis / debugging tools.
VIDEO FILTERS
When you configure your FFmpeg build, you can disable any of the existing filters using
"--disable-filters". The configure output will show the video filters included in your
build.
Below is a description of the currently available video filters.
addroi
Mark a region of interest in a video frame.
The frame data is passed through unchanged, but metadata is attached to the frame
indicating regions of interest which can affect the behaviour of later encoding. Multiple
regions can be marked by applying the filter multiple times.
x Region distance in pixels from the left edge of the frame.
y Region distance in pixels from the top edge of the frame.
w Region width in pixels.
h Region height in pixels.
The parameters x, y, w and h are expressions, and may contain the following variables:
iw Width of the input frame.
ih Height of the input frame.
qoffset
Quantisation offset to apply within the region.
This must be a real value in the range -1 to +1. A value of zero indicates no quality
change. A negative value asks for better quality (less quantisation), while a
positive value asks for worse quality (greater quantisation).
The range is calibrated so that the extreme values indicate the largest possible
offset - if the rest of the frame is encoded with the worst possible quality, an
offset of -1 indicates that this region should be encoded with the best possible
quality anyway. Intermediate values are then interpolated in some codec-dependent
way.
For example, in 10-bit H.264 the quantisation parameter varies between -12 and 51. A
typical qoffset value of -1/10 therefore indicates that this region should be encoded
with a QP around one-tenth of the full range better than the rest of the frame. So,
if most of the frame were to be encoded with a QP of around 30, this region would get
a QP of around 24 (an offset of approximately -1/10 * (51 - -12) = -6.3). An extreme
value of -1 would indicate that this region should be encoded with the best possible
quality regardless of the treatment of the rest of the frame - that is, should be
encoded at a QP of -12.
clear
If set to true, remove any existing regions of interest marked on the frame before
adding the new one.
Examples
• Mark the centre quarter of the frame as interesting.
addroi=iw/4:ih/4:iw/2:ih/2:-1/10
• Mark the 100-pixel-wide region on the left edge of the frame as very uninteresting (to
be encoded at much lower quality than the rest of the frame).
addroi=0:0:100:ih:+1/5
alphaextract
Extract the alpha component from the input as a grayscale video. This is especially useful
with the alphamerge filter.
alphamerge
Add or replace the alpha component of the primary input with the grayscale value of a
second input. This is intended for use with alphaextract to allow the transmission or
storage of frame sequences that have alpha in a format that doesn't support an alpha
channel.
For example, to reconstruct full frames from a normal YUV-encoded video and a separate
video created with alphaextract, you might use:
movie=in_alpha.mkv [alpha]; [in][alpha] alphamerge [out]
amplify
Amplify differences between current pixel and pixels of adjacent frames in same pixel
location.
This filter accepts the following options:
radius
Set frame radius. Default is 2. Allowed range is from 1 to 63. For example radius of
3 will instruct filter to calculate average of 7 frames.
factor
Set factor to amplify difference. Default is 2. Allowed range is from 0 to 65535.
threshold
Set threshold for difference amplification. Any difference greater or equal to this
value will not alter source pixel. Default is 10. Allowed range is from 0 to 65535.
tolerance
Set tolerance for difference amplification. Any difference lower to this value will
not alter source pixel. Default is 0. Allowed range is from 0 to 65535.
low Set lower limit for changing source pixel. Default is 65535. Allowed range is from 0
to 65535. This option controls maximum possible value that will decrease source pixel
value.
high
Set high limit for changing source pixel. Default is 65535. Allowed range is from 0 to
65535. This option controls maximum possible value that will increase source pixel
value.
planes
Set which planes to filter. Default is all. Allowed range is from 0 to 15.
Commands
This filter supports the following commands that corresponds to option of same name:
factor
threshold
tolerance
low
high
planes
ass
Same as the subtitles filter, except that it doesn't require libavcodec and libavformat to
work. On the other hand, it is limited to ASS (Advanced Substation Alpha) subtitles files.
This filter accepts the following option in addition to the common options from the
subtitles filter:
shaping
Set the shaping engine
Available values are:
auto
The default libass shaping engine, which is the best available.
simple
Fast, font-agnostic shaper that can do only substitutions
complex
Slower shaper using OpenType for substitutions and positioning
The default is "auto".
atadenoise
Apply an Adaptive Temporal Averaging Denoiser to the video input.
The filter accepts the following options:
0a Set threshold A for 1st plane. Default is 0.02. Valid range is 0 to 0.3.
0b Set threshold B for 1st plane. Default is 0.04. Valid range is 0 to 5.
1a Set threshold A for 2nd plane. Default is 0.02. Valid range is 0 to 0.3.
1b Set threshold B for 2nd plane. Default is 0.04. Valid range is 0 to 5.
2a Set threshold A for 3rd plane. Default is 0.02. Valid range is 0 to 0.3.
2b Set threshold B for 3rd plane. Default is 0.04. Valid range is 0 to 5.
Threshold A is designed to react on abrupt changes in the input signal and threshold B
is designed to react on continuous changes in the input signal.
s Set number of frames filter will use for averaging. Default is 9. Must be odd number
in range [5, 129].
p Set what planes of frame filter will use for averaging. Default is all.
a Set what variant of algorithm filter will use for averaging. Default is "p" parallel.
Alternatively can be set to "s" serial.
Parallel can be faster then serial, while other way around is never true. Parallel
will abort early on first change being greater then thresholds, while serial will
continue processing other side of frames if they are equal or below thresholds.
0s
1s
2s Set sigma for 1st plane, 2nd plane or 3rd plane. Default is 32767. Valid range is
from 0 to 32767. This options controls weight for each pixel in radius defined by
size. Default value means every pixel have same weight. Setting this option to 0
effectively disables filtering.
Commands
This filter supports same commands as options except option "s". The command accepts the
same syntax of the corresponding option.
avgblur
Apply average blur filter.
The filter accepts the following options:
sizeX
Set horizontal radius size.
planes
Set which planes to filter. By default all planes are filtered.
sizeY
Set vertical radius size, if zero it will be same as "sizeX". Default is 0.
Commands
This filter supports same commands as options. The command accepts the same syntax of the
corresponding option.
If the specified expression is not valid, it is kept at its current value.
backgroundkey
Turns a static background into transparency.
The filter accepts the following option:
threshold
Threshold for scene change detection.
similarity
Similarity percentage with the background.
blend
Set the blend amount for pixels that are not similar.
Commands
This filter supports the all above options as commands.
bbox
Compute the bounding box for the non-black pixels in the input frame luma plane.
This filter computes the bounding box containing all the pixels with a luma value greater
than the minimum allowed value. The parameters describing the bounding box are printed on
the filter log.
The filter accepts the following option:
min_val
Set the minimal luma value. Default is 16.
Commands
This filter supports the all above options as commands.
bilateral
Apply bilateral filter, spatial smoothing while preserving edges.
The filter accepts the following options:
sigmaS
Set sigma of gaussian function to calculate spatial weight. Allowed range is 0 to
512. Default is 0.1.
sigmaR
Set sigma of gaussian function to calculate range weight. Allowed range is 0 to 1.
Default is 0.1.
planes
Set planes to filter. Default is first only.
Commands
This filter supports the all above options as commands.
bilateral_cuda
CUDA accelerated bilateral filter, an edge preserving filter. This filter is
mathematically accurate thanks to the use of GPU acceleration. For best output quality,
use one to one chroma subsampling, i.e. yuv444p format.
The filter accepts the following options:
sigmaS
Set sigma of gaussian function to calculate spatial weight, also called sigma space.
Allowed range is 0.1 to 512. Default is 0.1.
sigmaR
Set sigma of gaussian function to calculate color range weight, also called sigma
color. Allowed range is 0.1 to 512. Default is 0.1.
window_size
Set window size of the bilateral function to determine the number of neighbours to
loop on. If the number entered is even, one will be added automatically. Allowed
range is 1 to 255. Default is 1.
Examples
• Apply the bilateral filter on a video.
./ffmpeg -v verbose \
-hwaccel cuda -hwaccel_output_format cuda -i input.mp4 \
-init_hw_device cuda \
-filter_complex \
" \
[0:v]scale_cuda=format=yuv444p[scaled_video];
[scaled_video]bilateral_cuda=window_size=9:sigmaS=3.0:sigmaR=50.0" \
-an -sn -c:v h264_nvenc -cq 20 out.mp4
bitplanenoise
Show and measure bit plane noise.
The filter accepts the following options:
bitplane
Set which plane to analyze. Default is 1.
filter
Filter out noisy pixels from "bitplane" set above. Default is disabled.
blackdetect
Detect video intervals that are (almost) completely black. Can be useful to detect chapter
transitions, commercials, or invalid recordings.
The filter outputs its detection analysis to both the log as well as frame metadata. If a
black segment of at least the specified minimum duration is found, a line with the start
and end timestamps as well as duration is printed to the log with level "info". In
addition, a log line with level "debug" is printed per frame showing the black amount
detected for that frame.
The filter also attaches metadata to the first frame of a black segment with key
"lavfi.black_start" and to the first frame after the black segment ends with key
"lavfi.black_end". The value is the frame's timestamp. This metadata is added regardless
of the minimum duration specified.
The filter accepts the following options:
black_min_duration, d
Set the minimum detected black duration expressed in seconds. It must be a non-
negative floating point number.
Default value is 2.0.
picture_black_ratio_th, pic_th
Set the threshold for considering a picture "black". Express the minimum value for
the ratio:
<nb_black_pixels> / <nb_pixels>
for which a picture is considered black. Default value is 0.98.
pixel_black_th, pix_th
Set the threshold for considering a pixel "black".
The threshold expresses the maximum pixel luma value for which a pixel is considered
"black". The provided value is scaled according to the following equation:
<absolute_threshold> = <luma_minimum_value> + <pixel_black_th> * <luma_range_size>
luma_range_size and luma_minimum_value depend on the input video format, the range is
[0-255] for YUV full-range formats and [16-235] for YUV non full-range formats.
Default value is 0.10.
The following example sets the maximum pixel threshold to the minimum value, and detects
only black intervals of 2 or more seconds:
blackdetect=d=2:pix_th=0.00
blackframe
Detect frames that are (almost) completely black. Can be useful to detect chapter
transitions or commercials. Output lines consist of the frame number of the detected
frame, the percentage of blackness, the position in the file if known or -1 and the
timestamp in seconds.
In order to display the output lines, you need to set the loglevel at least to the
AV_LOG_INFO value.
This filter exports frame metadata "lavfi.blackframe.pblack". The value represents the
percentage of pixels in the picture that are below the threshold value.
It accepts the following parameters:
amount
The percentage of the pixels that have to be below the threshold; it defaults to 98.
threshold, thresh
The threshold below which a pixel value is considered black; it defaults to 32.
blend
Blend two video frames into each other.
The "blend" filter takes two input streams and outputs one stream, the first input is the
"top" layer and second input is "bottom" layer. By default, the output terminates when
the longest input terminates.
The "tblend" (time blend) filter takes two consecutive frames from one single stream, and
outputs the result obtained by blending the new frame on top of the old frame.
A description of the accepted options follows.
c0_mode
c1_mode
c2_mode
c3_mode
all_mode
Set blend mode for specific pixel component or all pixel components in case of
all_mode. Default value is "normal".
Available values for component modes are:
addition
and
average
bleach
burn
darken
difference
divide
dodge
exclusion
extremity
freeze
geometric
glow
grainextract
grainmerge
hardlight
hardmix
hardoverlay
harmonic
heat
interpolate
lighten
linearlight
multiply
multiply128
negation
normal
or
overlay
phoenix
pinlight
reflect
screen
softdifference
softlight
stain
subtract
vividlight
xor
c0_opacity
c1_opacity
c2_opacity
c3_opacity
all_opacity
Set blend opacity for specific pixel component or all pixel components in case of
all_opacity. Only used in combination with pixel component blend modes.
c0_expr
c1_expr
c2_expr
c3_expr
all_expr
Set blend expression for specific pixel component or all pixel components in case of
all_expr. Note that related mode options will be ignored if those are set.
The expressions can use the following variables:
N The sequential number of the filtered frame, starting from 0.
X
Y the coordinates of the current sample
W
H the width and height of currently filtered plane
SW
SH Width and height scale for the plane being filtered. It is the ratio between the
dimensions of the current plane to the luma plane, e.g. for a "yuv420p" frame, the
values are "1,1" for the luma plane and "0.5,0.5" for the chroma planes.
T Time of the current frame, expressed in seconds.
TOP, A
Value of pixel component at current location for first video frame (top layer).
BOTTOM, B
Value of pixel component at current location for second video frame (bottom
layer).
The "blend" filter also supports the framesync options.
Examples
• Apply transition from bottom layer to top layer in first 10 seconds:
blend=all_expr='A*(if(gte(T,10),1,T/10))+B*(1-(if(gte(T,10),1,T/10)))'
• Apply linear horizontal transition from top layer to bottom layer:
blend=all_expr='A*(X/W)+B*(1-X/W)'
• Apply 1x1 checkerboard effect:
blend=all_expr='if(eq(mod(X,2),mod(Y,2)),A,B)'
• Apply uncover left effect:
blend=all_expr='if(gte(N*SW+X,W),A,B)'
• Apply uncover down effect:
blend=all_expr='if(gte(Y-N*SH,0),A,B)'
• Apply uncover up-left effect:
blend=all_expr='if(gte(T*SH*40+Y,H)*gte((T*40*SW+X)*W/H,W),A,B)'
• Split diagonally video and shows top and bottom layer on each side:
blend=all_expr='if(gt(X,Y*(W/H)),A,B)'
• Display differences between the current and the previous frame:
tblend=all_mode=grainextract
Commands
This filter supports same commands as options.
blockdetect
Determines blockiness of frames without altering the input frames.
Based on Remco Muijs and Ihor Kirenko: "A no-reference blocking artifact measure for
adaptive video processing." 2005 13th European signal processing conference.
The filter accepts the following options:
period_min
period_max
Set minimum and maximum values for determining pixel grids (periods). Default values
are [3,24].
planes
Set planes to filter. Default is first only.
Examples
• Determine blockiness for the first plane and search for periods within [8,32]:
blockdetect=period_min=8:period_max=32:planes=1
blurdetect
Determines blurriness of frames without altering the input frames.
Based on Marziliano, Pina, et al. "A no-reference perceptual blur metric." Allows for a
block-based abbreviation.
The filter accepts the following options:
low
high
Set low and high threshold values used by the Canny thresholding algorithm.
The high threshold selects the "strong" edge pixels, which are then connected through
8-connectivity with the "weak" edge pixels selected by the low threshold.
low and high threshold values must be chosen in the range [0,1], and low should be
lesser or equal to high.
Default value for low is "20/255", and default value for high is "50/255".
radius
Define the radius to search around an edge pixel for local maxima.
block_pct
Determine blurriness only for the most significant blocks, given in percentage.
block_width
Determine blurriness for blocks of width block_width. If set to any value smaller 1,
no blocks are used and the whole image is processed as one no matter of block_height.
block_height
Determine blurriness for blocks of height block_height. If set to any value smaller 1,
no blocks are used and the whole image is processed as one no matter of block_width.
planes
Set planes to filter. Default is first only.
Examples
• Determine blur for 80% of most significant 32x32 blocks:
blurdetect=block_width=32:block_height=32:block_pct=80
bm3d
Denoise frames using Block-Matching 3D algorithm.
The filter accepts the following options.
sigma
Set denoising strength. Default value is 1. Allowed range is from 0 to 999.9. The
denoising algorithm is very sensitive to sigma, so adjust it according to the source.
block
Set local patch size. This sets dimensions in 2D.
bstep
Set sliding step for processing blocks. Default value is 4. Allowed range is from 1
to 64. Smaller values allows processing more reference blocks and is slower.
group
Set maximal number of similar blocks for 3rd dimension. Default value is 1. When set
to 1, no block matching is done. Larger values allows more blocks in single group.
Allowed range is from 1 to 256.
range
Set radius for search block matching. Default is 9. Allowed range is from 1 to
INT32_MAX.
mstep
Set step between two search locations for block matching. Default is 1. Allowed range
is from 1 to 64. Smaller is slower.
thmse
Set threshold of mean square error for block matching. Valid range is 0 to INT32_MAX.
hdthr
Set thresholding parameter for hard thresholding in 3D transformed domain. Larger
values results in stronger hard-thresholding filtering in frequency domain.
estim
Set filtering estimation mode. Can be "basic" or "final". Default is "basic".
ref If enabled, filter will use 2nd stream for block matching. Default is disabled for
"basic" value of estim option, and always enabled if value of estim is "final".
planes
Set planes to filter. Default is all available except alpha.
Examples
• Basic filtering with bm3d:
bm3d=sigma=3:block=4:bstep=2:group=1:estim=basic
• Same as above, but filtering only luma:
bm3d=sigma=3:block=4:bstep=2:group=1:estim=basic:planes=1
• Same as above, but with both estimation modes:
split[a][b],[a]bm3d=sigma=3:block=4:bstep=2:group=1:estim=basic[a],[b][a]bm3d=sigma=3:block=4:bstep=2:group=16:estim=final:ref=1
• Same as above, but prefilter with nlmeans filter instead:
split[a][b],[a]nlmeans=s=3:r=7:p=3[a],[b][a]bm3d=sigma=3:block=4:bstep=2:group=16:estim=final:ref=1
boxblur
Apply a boxblur algorithm to the input video.
It accepts the following parameters:
luma_radius, lr
luma_power, lp
chroma_radius, cr
chroma_power, cp
alpha_radius, ar
alpha_power, ap
A description of the accepted options follows.
luma_radius, lr
chroma_radius, cr
alpha_radius, ar
Set an expression for the box radius in pixels used for blurring the corresponding
input plane.
The radius value must be a non-negative number, and must not be greater than the value
of the expression "min(w,h)/2" for the luma and alpha planes, and of "min(cw,ch)/2"
for the chroma planes.
Default value for luma_radius is "2". If not specified, chroma_radius and alpha_radius
default to the corresponding value set for luma_radius.
The expressions can contain the following constants:
w
h The input width and height in pixels.
cw
ch The input chroma image width and height in pixels.
hsub
vsub
The horizontal and vertical chroma subsample values. For example, for the pixel
format "yuv422p", hsub is 2 and vsub is 1.
luma_power, lp
chroma_power, cp
alpha_power, ap
Specify how many times the boxblur filter is applied to the corresponding plane.
Default value for luma_power is 2. If not specified, chroma_power and alpha_power
default to the corresponding value set for luma_power.
A value of 0 will disable the effect.
Examples
• Apply a boxblur filter with the luma, chroma, and alpha radii set to 2:
boxblur=luma_radius=2:luma_power=1
boxblur=2:1
• Set the luma radius to 2, and alpha and chroma radius to 0:
boxblur=2:1:cr=0:ar=0
• Set the luma and chroma radii to a fraction of the video dimension:
boxblur=luma_radius=min(h\,w)/10:luma_power=1:chroma_radius=min(cw\,ch)/10:chroma_power=1
bwdif
Deinterlace the input video ("bwdif" stands for "Bob Weaver Deinterlacing Filter").
Motion adaptive deinterlacing based on yadif with the use of w3fdif and cubic
interpolation algorithms. It accepts the following parameters:
mode
The interlacing mode to adopt. It accepts one of the following values:
0, send_frame
Output one frame for each frame.
1, send_field
Output one frame for each field.
The default value is "send_field".
parity
The picture field parity assumed for the input interlaced video. It accepts one of the
following values:
0, tff
Assume the top field is first.
1, bff
Assume the bottom field is first.
-1, auto
Enable automatic detection of field parity.
The default value is "auto". If the interlacing is unknown or the decoder does not
export this information, top field first will be assumed.
deint
Specify which frames to deinterlace. Accepts one of the following values:
0, all
Deinterlace all frames.
1, interlaced
Only deinterlace frames marked as interlaced.
The default value is "all".
bwdif_cuda
Deinterlace the input video using the bwdif algorithm, but implemented in CUDA so that it
can work as part of a GPU accelerated pipeline with nvdec and/or nvenc.
It accepts the following parameters:
mode
The interlacing mode to adopt. It accepts one of the following values:
0, send_frame
Output one frame for each frame.
1, send_field
Output one frame for each field.
The default value is "send_field".
parity
The picture field parity assumed for the input interlaced video. It accepts one of the
following values:
0, tff
Assume the top field is first.
1, bff
Assume the bottom field is first.
-1, auto
Enable automatic detection of field parity.
The default value is "auto". If the interlacing is unknown or the decoder does not
export this information, top field first will be assumed.
deint
Specify which frames to deinterlace. Accepts one of the following values:
0, all
Deinterlace all frames.
1, interlaced
Only deinterlace frames marked as interlaced.
The default value is "all".
ccrepack
Repack CEA-708 closed captioning side data
This filter fixes various issues seen with commerical encoders related to upstream
malformed CEA-708 payloads, specifically incorrect number of tuples (wrong cc_count for
the target FPS), and incorrect ordering of tuples (i.e. the CEA-608 tuples are not at the
first entries in the payload).
cas
Apply Contrast Adaptive Sharpen filter to video stream.
The filter accepts the following options:
strength
Set the sharpening strength. Default value is 0.
planes
Set planes to filter. Default value is to filter all planes except alpha plane.
Commands
This filter supports same commands as options.
chromahold
Remove all color information for all colors except for certain one.
The filter accepts the following options:
color
The color which will not be replaced with neutral chroma.
similarity
Similarity percentage with the above color. 0.01 matches only the exact key color,
while 1.0 matches everything.
blend
Blend percentage. 0.0 makes pixels either fully gray, or not gray at all. Higher
values result in more preserved color.
yuv Signals that the color passed is already in YUV instead of RGB.
Literal colors like "green" or "red" don't make sense with this enabled anymore. This
can be used to pass exact YUV values as hexadecimal numbers.
Commands
This filter supports same commands as options. The command accepts the same syntax of the
corresponding option.
If the specified expression is not valid, it is kept at its current value.
chromakey
YUV colorspace color/chroma keying.
The filter accepts the following options:
color
The color which will be replaced with transparency.
similarity
Similarity percentage with the key color.
0.01 matches only the exact key color, while 1.0 matches everything.
blend
Blend percentage.
0.0 makes pixels either fully transparent, or not transparent at all.
Higher values result in semi-transparent pixels, with a higher transparency the more
similar the pixels color is to the key color.
yuv Signals that the color passed is already in YUV instead of RGB.
Literal colors like "green" or "red" don't make sense with this enabled anymore. This
can be used to pass exact YUV values as hexadecimal numbers.
Commands
This filter supports same commands as options. The command accepts the same syntax of the
corresponding option.
If the specified expression is not valid, it is kept at its current value.
Examples
• Make every green pixel in the input image transparent:
ffmpeg -i input.png -vf chromakey=green out.png
• Overlay a greenscreen-video on top of a static black background.
ffmpeg -f lavfi -i color=c=black:s=1280x720 -i video.mp4 -shortest -filter_complex "[1:v]chromakey=0x70de77:0.1:0.2[ckout];[0:v][ckout]overlay[out]" -map "[out]" output.mkv
chromakey_cuda
CUDA accelerated YUV colorspace color/chroma keying.
This filter works like normal chromakey filter but operates on CUDA frames. for more
details and parameters see chromakey.
Examples
• Make all the green pixels in the input video transparent and use it as an overlay for
another video:
./ffmpeg \
-hwaccel cuda -hwaccel_output_format cuda -i input_green.mp4 \
-hwaccel cuda -hwaccel_output_format cuda -i base_video.mp4 \
-init_hw_device cuda \
-filter_complex \
" \
[0:v]chromakey_cuda=0x25302D:0.1:0.12:1[overlay_video]; \
[1:v]scale_cuda=format=yuv420p[base]; \
[base][overlay_video]overlay_cuda" \
-an -sn -c:v h264_nvenc -cq 20 output.mp4
• Process two software sources, explicitly uploading the frames:
./ffmpeg -init_hw_device cuda=cuda -filter_hw_device cuda \
-f lavfi -i color=size=800x600:color=white,format=yuv420p \
-f lavfi -i yuvtestsrc=size=200x200,format=yuv420p \
-filter_complex \
" \
[0]hwupload[under]; \
[1]hwupload,chromakey_cuda=green:0.1:0.12[over]; \
[under][over]overlay_cuda" \
-c:v hevc_nvenc -cq 18 -preset slow output.mp4
chromanr
Reduce chrominance noise.
The filter accepts the following options:
thres
Set threshold for averaging chrominance values. Sum of absolute difference of Y, U
and V pixel components of current pixel and neighbour pixels lower than this threshold
will be used in averaging. Luma component is left unchanged and is copied to output.
Default value is 30. Allowed range is from 1 to 200.
sizew
Set horizontal radius of rectangle used for averaging. Allowed range is from 1 to
100. Default value is 5.
sizeh
Set vertical radius of rectangle used for averaging. Allowed range is from 1 to 100.
Default value is 5.
stepw
Set horizontal step when averaging. Default value is 1. Allowed range is from 1 to
50. Mostly useful to speed-up filtering.
steph
Set vertical step when averaging. Default value is 1. Allowed range is from 1 to 50.
Mostly useful to speed-up filtering.
threy
Set Y threshold for averaging chrominance values. Set finer control for max allowed
difference between Y components of current pixel and neigbour pixels. Default value
is 200. Allowed range is from 1 to 200.
threu
Set U threshold for averaging chrominance values. Set finer control for max allowed
difference between U components of current pixel and neigbour pixels. Default value
is 200. Allowed range is from 1 to 200.
threv
Set V threshold for averaging chrominance values. Set finer control for max allowed
difference between V components of current pixel and neigbour pixels. Default value
is 200. Allowed range is from 1 to 200.
distance
Set distance type used in calculations.
manhattan
Absolute difference.
euclidean
Difference squared.
Default distance type is manhattan.
Commands
This filter supports same commands as options. The command accepts the same syntax of the
corresponding option.
chromashift
Shift chroma pixels horizontally and/or vertically.
The filter accepts the following options:
cbh Set amount to shift chroma-blue horizontally.
cbv Set amount to shift chroma-blue vertically.
crh Set amount to shift chroma-red horizontally.
crv Set amount to shift chroma-red vertically.
edge
Set edge mode, can be smear, default, or warp.
Commands
This filter supports the all above options as commands.
ciescope
Display CIE color diagram with pixels overlaid onto it.
The filter accepts the following options:
system
Set color system.
ntsc, 470m
ebu, 470bg
smpte
240m
apple
widergb
cie1931
rec709, hdtv
uhdtv, rec2020
dcip3
cie Set CIE system.
xyy
ucs
luv
gamuts
Set what gamuts to draw.
See "system" option for available values.
size, s
Set ciescope size, by default set to 512.
intensity, i
Set intensity used to map input pixel values to CIE diagram.
contrast
Set contrast used to draw tongue colors that are out of active color system gamut.
corrgamma
Correct gamma displayed on scope, by default enabled.
showwhite
Show white point on CIE diagram, by default disabled.
gamma
Set input gamma. Used only with XYZ input color space.
fill
Fill with CIE colors. By default is enabled.
codecview
Visualize information exported by some codecs.
Some codecs can export information through frames using side-data or other means. For
example, some MPEG based codecs export motion vectors through the export_mvs flag in the
codec flags2 option.
The filter accepts the following option:
block
Display block partition structure using the luma plane.
mv Set motion vectors to visualize.
Available flags for mv are:
pf forward predicted MVs of P-frames
bf forward predicted MVs of B-frames
bb backward predicted MVs of B-frames
qp Display quantization parameters using the chroma planes.
mv_type, mvt
Set motion vectors type to visualize. Includes MVs from all frames unless specified by
frame_type option.
Available flags for mv_type are:
fp forward predicted MVs
bp backward predicted MVs
frame_type, ft
Set frame type to visualize motion vectors of.
Available flags for frame_type are:
if intra-coded frames (I-frames)
pf predicted frames (P-frames)
bf bi-directionally predicted frames (B-frames)
Examples
• Visualize forward predicted MVs of all frames using ffplay:
ffplay -flags2 +export_mvs input.mp4 -vf codecview=mv_type=fp
• Visualize multi-directionals MVs of P and B-Frames using ffplay:
ffplay -flags2 +export_mvs input.mp4 -vf codecview=mv=pf+bf+bb
colorbalance
Modify intensity of primary colors (red, green and blue) of input frames.
The filter allows an input frame to be adjusted in the shadows, midtones or highlights
regions for the red-cyan, green-magenta or blue-yellow balance.
A positive adjustment value shifts the balance towards the primary color, a negative value
towards the complementary color.
The filter accepts the following options:
rs
gs
bs Adjust red, green and blue shadows (darkest pixels).
rm
gm
bm Adjust red, green and blue midtones (medium pixels).
rh
gh
bh Adjust red, green and blue highlights (brightest pixels).
Allowed ranges for options are "[-1.0, 1.0]". Defaults are 0.
pl Preserve lightness when changing color balance. Default is disabled.
Examples
• Add red color cast to shadows:
colorbalance=rs=.3
Commands
This filter supports the all above options as commands.
colorcontrast
Adjust color contrast between RGB components.
The filter accepts the following options:
rc Set the red-cyan contrast. Defaults is 0.0. Allowed range is from -1.0 to 1.0.
gm Set the green-magenta contrast. Defaults is 0.0. Allowed range is from -1.0 to 1.0.
by Set the blue-yellow contrast. Defaults is 0.0. Allowed range is from -1.0 to 1.0.
rcw
gmw
byw Set the weight of each "rc", "gm", "by" option value. Default value is 0.0. Allowed
range is from 0.0 to 1.0. If all weights are 0.0 filtering is disabled.
pl Set the amount of preserving lightness. Default value is 0.0. Allowed range is from
0.0 to 1.0.
Commands
This filter supports the all above options as commands.
colorcorrect
Adjust color white balance selectively for blacks and whites. This filter operates in YUV
colorspace.
The filter accepts the following options:
rl Set the red shadow spot. Allowed range is from -1.0 to 1.0. Default value is 0.
bl Set the blue shadow spot. Allowed range is from -1.0 to 1.0. Default value is 0.
rh Set the red highlight spot. Allowed range is from -1.0 to 1.0. Default value is 0.
bh Set the blue highlight spot. Allowed range is from -1.0 to 1.0. Default value is 0.
saturation
Set the amount of saturation. Allowed range is from -3.0 to 3.0. Default value is 1.
analyze
If set to anything other than "manual" it will analyze every frame and use derived
parameters for filtering output frame.
Possible values are:
manual
average
minmax
median
Default value is "manual".
Commands
This filter supports the all above options as commands.
colorchannelmixer
Adjust video input frames by re-mixing color channels.
This filter modifies a color channel by adding the values associated to the other channels
of the same pixels. For example if the value to modify is red, the output value will be:
<red>=<red>*<rr> + <blue>*<rb> + <green>*<rg> + <alpha>*<ra>
The filter accepts the following options:
rr
rg
rb
ra Adjust contribution of input red, green, blue and alpha channels for output red
channel. Default is 1 for rr, and 0 for rg, rb and ra.
gr
gg
gb
ga Adjust contribution of input red, green, blue and alpha channels for output green
channel. Default is 1 for gg, and 0 for gr, gb and ga.
br
bg
bb
ba Adjust contribution of input red, green, blue and alpha channels for output blue
channel. Default is 1 for bb, and 0 for br, bg and ba.
ar
ag
ab
aa Adjust contribution of input red, green, blue and alpha channels for output alpha
channel. Default is 1 for aa, and 0 for ar, ag and ab.
Allowed ranges for options are "[-2.0, 2.0]".
pc Set preserve color mode. The accepted values are:
none
Disable color preserving, this is default.
lum Preserve luminance.
max Preserve max value of RGB triplet.
avg Preserve average value of RGB triplet.
sum Preserve sum value of RGB triplet.
nrm Preserve normalized value of RGB triplet.
pwr Preserve power value of RGB triplet.
pa Set the preserve color amount when changing colors. Allowed range is from "[0.0,
1.0]". Default is 0.0, thus disabled.
Examples
• Convert source to grayscale:
colorchannelmixer=.3:.4:.3:0:.3:.4:.3:0:.3:.4:.3
• Simulate sepia tones:
colorchannelmixer=.393:.769:.189:0:.349:.686:.168:0:.272:.534:.131
Commands
This filter supports the all above options as commands.
colorize
Overlay a solid color on the video stream.
The filter accepts the following options:
hue Set the color hue. Allowed range is from 0 to 360. Default value is 0.
saturation
Set the color saturation. Allowed range is from 0 to 1. Default value is 0.5.
lightness
Set the color lightness. Allowed range is from 0 to 1. Default value is 0.5.
mix Set the mix of source lightness. By default is set to 1.0. Allowed range is from 0.0
to 1.0.
Commands
This filter supports the all above options as commands.
colorkey
RGB colorspace color keying. This filter operates on 8-bit RGB format frames by setting
the alpha component of each pixel which falls within the similarity radius of the key
color to 0. The alpha value for pixels outside the similarity radius depends on the value
of the blend option.
The filter accepts the following options:
color
Set the color for which alpha will be set to 0 (full transparency). See "Color"
section in the ffmpeg-utils manual. Default is "black".
similarity
Set the radius from the key color within which other colors also have full
transparency. The computed distance is related to the unit fractional distance in 3D
space between the RGB values of the key color and the pixel's color. Range is 0.01 to
1.0. 0.01 matches within a very small radius around the exact key color, while 1.0
matches everything. Default is 0.01.
blend
Set how the alpha value for pixels that fall outside the similarity radius is
computed. 0.0 makes pixels either fully transparent or fully opaque. Higher values
result in semi-transparent pixels, with greater transparency the more similar the
pixel color is to the key color. Range is 0.0 to 1.0. Default is 0.0.
Examples
• Make every green pixel in the input image transparent:
ffmpeg -i input.png -vf colorkey=green out.png
• Overlay a greenscreen-video on top of a static background image.
ffmpeg -i background.png -i video.mp4 -filter_complex "[1:v]colorkey=0x3BBD1E:0.3:0.2[ckout];[0:v][ckout]overlay[out]" -map "[out]" output.flv
Commands
This filter supports same commands as options. The command accepts the same syntax of the
corresponding option.
If the specified expression is not valid, it is kept at its current value.
colorhold
Remove all color information for all RGB colors except for certain one.
The filter accepts the following options:
color
The color which will not be replaced with neutral gray.
similarity
Similarity percentage with the above color. 0.01 matches only the exact key color,
while 1.0 matches everything.
blend
Blend percentage. 0.0 makes pixels fully gray. Higher values result in more preserved
color.
Commands
This filter supports same commands as options. The command accepts the same syntax of the
corresponding option.
If the specified expression is not valid, it is kept at its current value.
colorlevels
Adjust video input frames using levels.
The filter accepts the following options:
rimin
gimin
bimin
aimin
Adjust red, green, blue and alpha input black point. Allowed ranges for options are
"[-1.0, 1.0]". Defaults are 0.
rimax
gimax
bimax
aimax
Adjust red, green, blue and alpha input white point. Allowed ranges for options are
"[-1.0, 1.0]". Defaults are 1.
Input levels are used to lighten highlights (bright tones), darken shadows (dark
tones), change the balance of bright and dark tones.
romin
gomin
bomin
aomin
Adjust red, green, blue and alpha output black point. Allowed ranges for options are
"[0, 1.0]". Defaults are 0.
romax
gomax
bomax
aomax
Adjust red, green, blue and alpha output white point. Allowed ranges for options are
"[0, 1.0]". Defaults are 1.
Output levels allows manual selection of a constrained output level range.
preserve
Set preserve color mode. The accepted values are:
none
Disable color preserving, this is default.
lum Preserve luminance.
max Preserve max value of RGB triplet.
avg Preserve average value of RGB triplet.
sum Preserve sum value of RGB triplet.
nrm Preserve normalized value of RGB triplet.
pwr Preserve power value of RGB triplet.
Examples
• Make video output darker:
colorlevels=rimin=0.058:gimin=0.058:bimin=0.058
• Increase contrast:
colorlevels=rimin=0.039:gimin=0.039:bimin=0.039:rimax=0.96:gimax=0.96:bimax=0.96
• Make video output lighter:
colorlevels=rimax=0.902:gimax=0.902:bimax=0.902
• Increase brightness:
colorlevels=romin=0.5:gomin=0.5:bomin=0.5
Commands
This filter supports the all above options as commands.
colormap
Apply custom color maps to video stream.
This filter needs three input video streams. First stream is video stream that is going
to be filtered out. Second and third video stream specify color patches for source color
to target color mapping.
The filter accepts the following options:
patch_size
Set the source and target video stream patch size in pixels.
nb_patches
Set the max number of used patches from source and target video stream. Default value
is number of patches available in additional video streams. Max allowed number of
patches is 64.
type
Set the adjustments used for target colors. Can be "relative" or "absolute". Defaults
is "absolute".
kernel
Set the kernel used to measure color differences between mapped colors.
The accepted values are:
euclidean
weuclidean
Default is "euclidean".
colormatrix
Convert color matrix.
The filter accepts the following options:
src
dst Specify the source and destination color matrix. Both values must be specified.
The accepted values are:
bt709
BT.709
fcc FCC
bt601
BT.601
bt470
BT.470
bt470bg
BT.470BG
smpte170m
SMPTE-170M
smpte240m
SMPTE-240M
bt2020
BT.2020
For example to convert from BT.601 to SMPTE-240M, use the command:
colormatrix=bt601:smpte240m
colorspace
Convert colorspace, transfer characteristics or color primaries. Input video needs to
have an even size.
The filter accepts the following options:
all Specify all color properties at once.
The accepted values are:
bt470m
BT.470M
bt470bg
BT.470BG
bt601-6-525
BT.601-6 525
bt601-6-625
BT.601-6 625
bt709
BT.709
smpte170m
SMPTE-170M
smpte240m
SMPTE-240M
bt2020
BT.2020
space
Specify output colorspace.
The accepted values are:
bt709
BT.709
fcc FCC
bt470bg
BT.470BG or BT.601-6 625
smpte170m
SMPTE-170M or BT.601-6 525
smpte240m
SMPTE-240M
ycgco
YCgCo
bt2020ncl
BT.2020 with non-constant luminance
trc Specify output transfer characteristics.
The accepted values are:
bt709
BT.709
bt470m
BT.470M
bt470bg
BT.470BG
gamma22
Constant gamma of 2.2
gamma28
Constant gamma of 2.8
smpte170m
SMPTE-170M, BT.601-6 625 or BT.601-6 525
smpte240m
SMPTE-240M
srgb
SRGB
iec61966-2-1
iec61966-2-1
iec61966-2-4
iec61966-2-4
xvycc
xvycc
bt2020-10
BT.2020 for 10-bits content
bt2020-12
BT.2020 for 12-bits content
primaries
Specify output color primaries.
The accepted values are:
bt709
BT.709
bt470m
BT.470M
bt470bg
BT.470BG or BT.601-6 625
smpte170m
SMPTE-170M or BT.601-6 525
smpte240m
SMPTE-240M
film
film
smpte431
SMPTE-431
smpte432
SMPTE-432
bt2020
BT.2020
jedec-p22
JEDEC P22 phosphors
range
Specify output color range.
The accepted values are:
tv TV (restricted) range
mpeg
MPEG (restricted) range
pc PC (full) range
jpeg
JPEG (full) range
format
Specify output color format.
The accepted values are:
yuv420p
YUV 4:2:0 planar 8-bits
yuv420p10
YUV 4:2:0 planar 10-bits
yuv420p12
YUV 4:2:0 planar 12-bits
yuv422p
YUV 4:2:2 planar 8-bits
yuv422p10
YUV 4:2:2 planar 10-bits
yuv422p12
YUV 4:2:2 planar 12-bits
yuv444p
YUV 4:4:4 planar 8-bits
yuv444p10
YUV 4:4:4 planar 10-bits
yuv444p12
YUV 4:4:4 planar 12-bits
fast
Do a fast conversion, which skips gamma/primary correction. This will take
significantly less CPU, but will be mathematically incorrect. To get output compatible
with that produced by the colormatrix filter, use fast=1.
dither
Specify dithering mode.
The accepted values are:
none
No dithering
fsb Floyd-Steinberg dithering
wpadapt
Whitepoint adaptation mode.
The accepted values are:
bradford
Bradford whitepoint adaptation
vonkries
von Kries whitepoint adaptation
identity
identity whitepoint adaptation (i.e. no whitepoint adaptation)
iall
Override all input properties at once. Same accepted values as all.
ispace
Override input colorspace. Same accepted values as space.
iprimaries
Override input color primaries. Same accepted values as primaries.
itrc
Override input transfer characteristics. Same accepted values as trc.
irange
Override input color range. Same accepted values as range.
The filter converts the transfer characteristics, color space and color primaries to the
specified user values. The output value, if not specified, is set to a default value based
on the "all" property. If that property is also not specified, the filter will log an
error. The output color range and format default to the same value as the input color
range and format. The input transfer characteristics, color space, color primaries and
color range should be set on the input data. If any of these are missing, the filter will
log an error and no conversion will take place.
For example to convert the input to SMPTE-240M, use the command:
colorspace=smpte240m
colorspace_cuda
CUDA accelerated implementation of the colorspace filter.
It is by no means feature complete compared to the software colorspace filter, and at the
current time only supports color range conversion between jpeg/full and mpeg/limited
range.
The filter accepts the following options:
range
Specify output color range.
The accepted values are:
tv TV (restricted) range
mpeg
MPEG (restricted) range
pc PC (full) range
jpeg
JPEG (full) range
colortemperature
Adjust color temperature in video to simulate variations in ambient color temperature.
The filter accepts the following options:
temperature
Set the temperature in Kelvin. Allowed range is from 1000 to 40000. Default value is
6500 K.
mix Set mixing with filtered output. Allowed range is from 0 to 1. Default value is 1.
pl Set the amount of preserving lightness. Allowed range is from 0 to 1. Default value
is 0.
Commands
This filter supports same commands as options.
convolution
Apply convolution of 3x3, 5x5, 7x7 or horizontal/vertical up to 49 elements.
The filter accepts the following options:
0m
1m
2m
3m Set matrix for each plane. Matrix is sequence of 9, 25 or 49 signed integers in
square mode, and from 1 to 49 odd number of signed integers in row mode.
0rdiv
1rdiv
2rdiv
3rdiv
Set multiplier for calculated value for each plane. If unset or 0, it will be 1/sum
of all matrix elements.
0bias
1bias
2bias
3bias
Set bias for each plane. This value is added to the result of the multiplication.
Useful for making the overall image brighter or darker. Default is 0.0.
0mode
1mode
2mode
3mode
Set matrix mode for each plane. Can be square, row or column. Default is square.
Commands
This filter supports the all above options as commands.
Examples
• Apply sharpen:
convolution="0 -1 0 -1 5 -1 0 -1 0:0 -1 0 -1 5 -1 0 -1 0:0 -1 0 -1 5 -1 0 -1 0:0 -1 0 -1 5 -1 0 -1 0"
• Apply blur:
convolution="1 1 1 1 1 1 1 1 1:1 1 1 1 1 1 1 1 1:1 1 1 1 1 1 1 1 1:1 1 1 1 1 1 1 1 1:1/9:1/9:1/9:1/9"
• Apply edge enhance:
convolution="0 0 0 -1 1 0 0 0 0:0 0 0 -1 1 0 0 0 0:0 0 0 -1 1 0 0 0 0:0 0 0 -1 1 0 0 0 0:5:1:1:1:0:128:128:128"
• Apply edge detect:
convolution="0 1 0 1 -4 1 0 1 0:0 1 0 1 -4 1 0 1 0:0 1 0 1 -4 1 0 1 0:0 1 0 1 -4 1 0 1 0:5:5:5:1:0:128:128:128"
• Apply laplacian edge detector which includes diagonals:
convolution="1 1 1 1 -8 1 1 1 1:1 1 1 1 -8 1 1 1 1:1 1 1 1 -8 1 1 1 1:1 1 1 1 -8 1 1 1 1:5:5:5:1:0:128:128:0"
• Apply emboss:
convolution="-2 -1 0 -1 1 1 0 1 2:-2 -1 0 -1 1 1 0 1 2:-2 -1 0 -1 1 1 0 1 2:-2 -1 0 -1 1 1 0 1 2"
convolve
Apply 2D convolution of video stream in frequency domain using second stream as impulse.
The filter accepts the following options:
planes
Set which planes to process.
impulse
Set which impulse video frames will be processed, can be first or all. Default is all.
The "convolve" filter also supports the framesync options.
copy
Copy the input video source unchanged to the output. This is mainly useful for testing
purposes.
coreimage
Video filtering on GPU using Apple's CoreImage API on OSX.
Hardware acceleration is based on an OpenGL context. Usually, this means it is processed
by video hardware. However, software-based OpenGL implementations exist which means there
is no guarantee for hardware processing. It depends on the respective OSX.
There are many filters and image generators provided by Apple that come with a large
variety of options. The filter has to be referenced by its name along with its options.
The coreimage filter accepts the following options:
list_filters
List all available filters and generators along with all their respective options as
well as possible minimum and maximum values along with the default values.
list_filters=true
filter
Specify all filters by their respective name and options. Use list_filters to
determine all valid filter names and options. Numerical options are specified by a
float value and are automatically clamped to their respective value range. Vector and
color options have to be specified by a list of space separated float values.
Character escaping has to be done. A special option name "default" is available to
use default options for a filter.
It is required to specify either "default" or at least one of the filter options. All
omitted options are used with their default values. The syntax of the filter string
is as follows:
filter=<NAME>@<OPTION>=<VALUE>[@<OPTION>=<VALUE>][@...][#<NAME>@<OPTION>=<VALUE>[@<OPTION>=<VALUE>][@...]][#...]
output_rect
Specify a rectangle where the output of the filter chain is copied into the input
image. It is given by a list of space separated float values:
output_rect=x\ y\ width\ height
If not given, the output rectangle equals the dimensions of the input image. The
output rectangle is automatically cropped at the borders of the input image. Negative
values are valid for each component.
output_rect=25\ 25\ 100\ 100
Several filters can be chained for successive processing without GPU-HOST transfers
allowing for fast processing of complex filter chains. Currently, only filters with zero
(generators) or exactly one (filters) input image and one output image are supported.
Also, transition filters are not yet usable as intended.
Some filters generate output images with additional padding depending on the respective
filter kernel. The padding is automatically removed to ensure the filter output has the
same size as the input image.
For image generators, the size of the output image is determined by the previous output
image of the filter chain or the input image of the whole filterchain, respectively. The
generators do not use the pixel information of this image to generate their output.
However, the generated output is blended onto this image, resulting in partial or complete
coverage of the output image.
The coreimagesrc video source can be used for generating input images which are directly
fed into the filter chain. By using it, providing input images by another video source or
an input video is not required.
Examples
• List all filters available:
coreimage=list_filters=true
• Use the CIBoxBlur filter with default options to blur an image:
coreimage=filter=CIBoxBlur@default
• Use a filter chain with CISepiaTone at default values and CIVignetteEffect with its
center at 100x100 and a radius of 50 pixels:
coreimage=filter=CIBoxBlur@default#CIVignetteEffect@inputCenter=100\ 100@inputRadius=50
• Use nullsrc and CIQRCodeGenerator to create a QR code for the FFmpeg homepage, given
as complete and escaped command-line for Apple's standard bash shell:
ffmpeg -f lavfi -i nullsrc=s=100x100,coreimage=filter=CIQRCodeGenerator@inputMessage=https\\\\\://FFmpeg.org/@inputCorrectionLevel=H -frames:v 1 QRCode.png
corr
Obtain the correlation between two input videos.
This filter takes two input videos.
Both input videos must have the same resolution and pixel format for this filter to work
correctly. Also it assumes that both inputs have the same number of frames, which are
compared one by one.
The obtained per component, average, min and max correlation is printed through the
logging system.
The filter stores the calculated correlation of each frame in frame metadata.
This filter also supports the framesync options.
In the below example the input file main.mpg being processed is compared with the
reference file ref.mpg.
ffmpeg -i main.mpg -i ref.mpg -lavfi corr -f null -
cover_rect
Cover a rectangular object
It accepts the following options:
cover
Filepath of the optional cover image, needs to be in yuv420.
mode
Set covering mode.
It accepts the following values:
cover
cover it by the supplied image
blur
cover it by interpolating the surrounding pixels
Default value is blur.
Examples
• Cover a rectangular object by the supplied image of a given video using ffmpeg:
ffmpeg -i file.ts -vf find_rect=newref.pgm,cover_rect=cover.jpg:mode=cover new.mkv
crop
Crop the input video to given dimensions.
It accepts the following parameters:
w, out_w
The width of the output video. It defaults to "iw". This expression is evaluated only
once during the filter configuration, or when the w or out_w command is sent.
h, out_h
The height of the output video. It defaults to "ih". This expression is evaluated
only once during the filter configuration, or when the h or out_h command is sent.
x The horizontal position, in the input video, of the left edge of the output video. It
defaults to "(in_w-out_w)/2". This expression is evaluated per-frame.
y The vertical position, in the input video, of the top edge of the output video. It
defaults to "(in_h-out_h)/2". This expression is evaluated per-frame.
keep_aspect
If set to 1 will force the output display aspect ratio to be the same of the input, by
changing the output sample aspect ratio. It defaults to 0.
exact
Enable exact cropping. If enabled, subsampled videos will be cropped at exact
width/height/x/y as specified and will not be rounded to nearest smaller value. It
defaults to 0.
The out_w, out_h, x, y parameters are expressions containing the following constants:
x
y The computed values for x and y. They are evaluated for each new frame.
in_w
in_h
The input width and height.
iw
ih These are the same as in_w and in_h.
out_w
out_h
The output (cropped) width and height.
ow
oh These are the same as out_w and out_h.
a same as iw / ih
sar input sample aspect ratio
dar input display aspect ratio, it is the same as (iw / ih) * sar
hsub
vsub
horizontal and vertical chroma subsample values. For example for the pixel format
"yuv422p" hsub is 2 and vsub is 1.
n The number of the input frame, starting from 0.
pos the position in the file of the input frame, NAN if unknown; deprecated, do not use
t The timestamp expressed in seconds. It's NAN if the input timestamp is unknown.
The expression for out_w may depend on the value of out_h, and the expression for out_h
may depend on out_w, but they cannot depend on x and y, as x and y are evaluated after
out_w and out_h.
The x and y parameters specify the expressions for the position of the top-left corner of
the output (non-cropped) area. They are evaluated for each frame. If the evaluated value
is not valid, it is approximated to the nearest valid value.
The expression for x may depend on y, and the expression for y may depend on x.
Examples
• Crop area with size 100x100 at position (12,34).
crop=100:100:12:34
Using named options, the example above becomes:
crop=w=100:h=100:x=12:y=34
• Crop the central input area with size 100x100:
crop=100:100
• Crop the central input area with size 2/3 of the input video:
crop=2/3*in_w:2/3*in_h
• Crop the input video central square:
crop=out_w=in_h
crop=in_h
• Delimit the rectangle with the top-left corner placed at position 100:100 and the
right-bottom corner corresponding to the right-bottom corner of the input image.
crop=in_w-100:in_h-100:100:100
• Crop 10 pixels from the left and right borders, and 20 pixels from the top and bottom
borders
crop=in_w-2*10:in_h-2*20
• Keep only the bottom right quarter of the input image:
crop=in_w/2:in_h/2:in_w/2:in_h/2
• Crop height for getting Greek harmony:
crop=in_w:1/PHI*in_w
• Apply trembling effect:
crop=in_w/2:in_h/2:(in_w-out_w)/2+((in_w-out_w)/2)*sin(n/10):(in_h-out_h)/2 +((in_h-out_h)/2)*sin(n/7)
• Apply erratic camera effect depending on timestamp:
crop=in_w/2:in_h/2:(in_w-out_w)/2+((in_w-out_w)/2)*sin(t*10):(in_h-out_h)/2 +((in_h-out_h)/2)*sin(t*13)
• Set x depending on the value of y:
crop=in_w/2:in_h/2:y:10+10*sin(n/10)
Commands
This filter supports the following commands:
w, out_w
h, out_h
x
y Set width/height of the output video and the horizontal/vertical position in the input
video. The command accepts the same syntax of the corresponding option.
If the specified expression is not valid, it is kept at its current value.
cropdetect
Auto-detect the crop size.
It calculates the necessary cropping parameters and prints the recommended parameters via
the logging system. The detected dimensions correspond to the non-black or video area of
the input video according to mode.
It accepts the following parameters:
mode
Depending on mode crop detection is based on either the mere black value of
surrounding pixels or a combination of motion vectors and edge pixels.
black
Detect black pixels surrounding the playing video. For fine control use option
limit.
mvedges
Detect the playing video by the motion vectors inside the video and scanning for
edge pixels typically forming the border of a playing video.
limit
Set higher black value threshold, which can be optionally specified from nothing (0)
to everything (255 for 8-bit based formats). An intensity value greater to the set
value is considered non-black. It defaults to 24. You can also specify a value
between 0.0 and 1.0 which will be scaled depending on the bitdepth of the pixel
format.
round
The value which the width/height should be divisible by. It defaults to 16. The offset
is automatically adjusted to center the video. Use 2 to get only even dimensions
(needed for 4:2:2 video). 16 is best when encoding to most video codecs.
skip
Set the number of initial frames for which evaluation is skipped. Default is 2. Range
is 0 to INT_MAX.
reset_count, reset
Set the counter that determines after how many frames cropdetect will reset the
previously detected largest video area and start over to detect the current optimal
crop area. Default value is 0.
This can be useful when channel logos distort the video area. 0 indicates 'never
reset', and returns the largest area encountered during playback.
mv_threshold
Set motion in pixel units as threshold for motion detection. It defaults to 8.
low
high
Set low and high threshold values used by the Canny thresholding algorithm.
The high threshold selects the "strong" edge pixels, which are then connected through
8-connectivity with the "weak" edge pixels selected by the low threshold.
low and high threshold values must be chosen in the range [0,1], and low should be
lesser or equal to high.
Default value for low is "5/255", and default value for high is "15/255".
Examples
• Find video area surrounded by black borders:
ffmpeg -i file.mp4 -vf cropdetect,metadata=mode=print -f null -
• Find an embedded video area, generate motion vectors beforehand:
ffmpeg -i file.mp4 -vf mestimate,cropdetect=mode=mvedges,metadata=mode=print -f null -
• Find an embedded video area, use motion vectors from decoder:
ffmpeg -flags2 +export_mvs -i file.mp4 -vf cropdetect=mode=mvedges,metadata=mode=print -f null -
Commands
This filter supports the following commands:
limit
The command accepts the same syntax of the corresponding option. If the specified
expression is not valid, it is kept at its current value.
cue
Delay video filtering until a given wallclock timestamp. The filter first passes on
preroll amount of frames, then it buffers at most buffer amount of frames and waits for
the cue. After reaching the cue it forwards the buffered frames and also any subsequent
frames coming in its input.
The filter can be used synchronize the output of multiple ffmpeg processes for realtime
output devices like decklink. By putting the delay in the filtering chain and pre-
buffering frames the process can pass on data to output almost immediately after the
target wallclock timestamp is reached.
Perfect frame accuracy cannot be guaranteed, but the result is good enough for some use
cases.
cue The cue timestamp expressed in a UNIX timestamp in microseconds. Default is 0.
preroll
The duration of content to pass on as preroll expressed in seconds. Default is 0.
buffer
The maximum duration of content to buffer before waiting for the cue expressed in
seconds. Default is 0.
curves
Apply color adjustments using curves.
This filter is similar to the Adobe Photoshop and GIMP curves tools. Each component (red,
green and blue) has its values defined by N key points tied from each other using a smooth
curve. The x-axis represents the pixel values from the input frame, and the y-axis the new
pixel values to be set for the output frame.
By default, a component curve is defined by the two points (0;0) and (1;1). This creates a
straight line where each original pixel value is "adjusted" to its own value, which means
no change to the image.
The filter allows you to redefine these two points and add some more. A new curve will be
defined to pass smoothly through all these new coordinates. The new defined points need to
be strictly increasing over the x-axis, and their x and y values must be in the [0;1]
interval. The curve is formed by using a natural or monotonic cubic spline interpolation,
depending on the interp option (default: "natural"). The "natural" spline produces a
smoother curve in general while the monotonic ("pchip") spline guarantees the transitions
between the specified points to be monotonic. If the computed curves happened to go
outside the vector spaces, the values will be clipped accordingly.
The filter accepts the following options:
preset
Select one of the available color presets. This option can be used in addition to the
r, g, b parameters; in this case, the later options takes priority on the preset
values. Available presets are:
none
color_negative
cross_process
darker
increase_contrast
lighter
linear_contrast
medium_contrast
negative
strong_contrast
vintage
Default is "none".
master, m
Set the master key points. These points will define a second pass mapping. It is
sometimes called a "luminance" or "value" mapping. It can be used with r, g, b or all
since it acts like a post-processing LUT.
red, r
Set the key points for the red component.
green, g
Set the key points for the green component.
blue, b
Set the key points for the blue component.
all Set the key points for all components (not including master). Can be used in addition
to the other key points component options. In this case, the unset component(s) will
fallback on this all setting.
psfile
Specify a Photoshop curves file (".acv") to import the settings from.
plot
Save Gnuplot script of the curves in specified file.
interp
Specify the kind of interpolation. Available algorithms are:
natural
Natural cubic spline using a piece-wise cubic polynomial that is twice
continuously differentiable.
pchip
Monotonic cubic spline using a piecewise cubic Hermite interpolating polynomial
(PCHIP).
To avoid some filtergraph syntax conflicts, each key points list need to be defined using
the following syntax: "x0/y0 x1/y1 x2/y2 ...".
Commands
This filter supports same commands as options.
Examples
• Increase slightly the middle level of blue:
curves=blue='0/0 0.5/0.58 1/1'
• Vintage effect:
curves=r='0/0.11 .42/.51 1/0.95':g='0/0 0.50/0.48 1/1':b='0/0.22 .49/.44 1/0.8'
Here we obtain the following coordinates for each components:
red "(0;0.11) (0.42;0.51) (1;0.95)"
green
"(0;0) (0.50;0.48) (1;1)"
blue
"(0;0.22) (0.49;0.44) (1;0.80)"
• The previous example can also be achieved with the associated built-in preset:
curves=preset=vintage
• Or simply:
curves=vintage
• Use a Photoshop preset and redefine the points of the green component:
curves=psfile='MyCurvesPresets/purple.acv':green='0/0 0.45/0.53 1/1'
• Check out the curves of the "cross_process" profile using ffmpeg and gnuplot:
ffmpeg -f lavfi -i color -vf curves=cross_process:plot=/tmp/curves.plt -frames:v 1 -f null -
gnuplot -p /tmp/curves.plt
datascope
Video data analysis filter.
This filter shows hexadecimal pixel values of part of video.
The filter accepts the following options:
size, s
Set output video size.
x Set x offset from where to pick pixels.
y Set y offset from where to pick pixels.
mode
Set scope mode, can be one of the following:
mono
Draw hexadecimal pixel values with white color on black background.
color
Draw hexadecimal pixel values with input video pixel color on black background.
color2
Draw hexadecimal pixel values on color background picked from input video, the
text color is picked in such way so its always visible.
axis
Draw rows and columns numbers on left and top of video.
opacity
Set background opacity.
format
Set display number format. Can be "hex", or "dec". Default is "hex".
components
Set pixel components to display. By default all pixel components are displayed.
Commands
This filter supports same commands as options excluding "size" option.
dblur
Apply Directional blur filter.
The filter accepts the following options:
angle
Set angle of directional blur. Default is 45.
radius
Set radius of directional blur. Default is 5.
planes
Set which planes to filter. By default all planes are filtered.
Commands
This filter supports same commands as options. The command accepts the same syntax of the
corresponding option.
If the specified expression is not valid, it is kept at its current value.
dctdnoiz
Denoise frames using 2D DCT (frequency domain filtering).
This filter is not designed for real time.
The filter accepts the following options:
sigma, s
Set the noise sigma constant.
This sigma defines a hard threshold of "3 * sigma"; every DCT coefficient (absolute
value) below this threshold with be dropped.
If you need a more advanced filtering, see expr.
Default is 0.
overlap
Set number overlapping pixels for each block. Since the filter can be slow, you may
want to reduce this value, at the cost of a less effective filter and the risk of
various artefacts.
If the overlapping value doesn't permit processing the whole input width or height, a
warning will be displayed and according borders won't be denoised.
Default value is blocksize-1, which is the best possible setting.
expr, e
Set the coefficient factor expression.
For each coefficient of a DCT block, this expression will be evaluated as a multiplier
value for the coefficient.
If this is option is set, the sigma option will be ignored.
The absolute value of the coefficient can be accessed through the c variable.
n Set the blocksize using the number of bits. "1<<n" defines the blocksize, which is the
width and height of the processed blocks.
The default value is 3 (8x8) and can be raised to 4 for a blocksize of 16x16. Note
that changing this setting has huge consequences on the speed processing. Also, a
larger block size does not necessarily means a better de-noising.
Examples
Apply a denoise with a sigma of 4.5:
dctdnoiz=4.5
The same operation can be achieved using the expression system:
dctdnoiz=e='gte(c, 4.5*3)'
Violent denoise using a block size of "16x16":
dctdnoiz=15:n=4
deband
Remove banding artifacts from input video. It works by replacing banded pixels with
average value of referenced pixels.
The filter accepts the following options:
1thr
2thr
3thr
4thr
Set banding detection threshold for each plane. Default is 0.02. Valid range is
0.00003 to 0.5. If difference between current pixel and reference pixel is less than
threshold, it will be considered as banded.
range, r
Banding detection range in pixels. Default is 16. If positive, random number in range
0 to set value will be used. If negative, exact absolute value will be used. The
range defines square of four pixels around current pixel.
direction, d
Set direction in radians from which four pixel will be compared. If positive, random
direction from 0 to set direction will be picked. If negative, exact of absolute value
will be picked. For example direction 0, -PI or -2*PI radians will pick only pixels on
same row and -PI/2 will pick only pixels on same column.
blur, b
If enabled, current pixel is compared with average value of all four surrounding
pixels. The default is enabled. If disabled current pixel is compared with all four
surrounding pixels. The pixel is considered banded if only all four differences with
surrounding pixels are less than threshold.
coupling, c
If enabled, current pixel is changed if and only if all pixel components are banded,
e.g. banding detection threshold is triggered for all color components. The default
is disabled.
Commands
This filter supports the all above options as commands.
deblock
Remove blocking artifacts from input video.
The filter accepts the following options:
filter
Set filter type, can be weak or strong. Default is strong. This controls what kind of
deblocking is applied.
block
Set size of block, allowed range is from 4 to 512. Default is 8.
alpha
beta
gamma
delta
Set blocking detection thresholds. Allowed range is 0 to 1. Defaults are: 0.098 for
alpha and 0.05 for the rest. Using higher threshold gives more deblocking strength.
Setting alpha controls threshold detection at exact edge of block. Remaining options
controls threshold detection near the edge. Each one for below/above or left/right.
Setting any of those to 0 disables deblocking.
planes
Set planes to filter. Default is to filter all available planes.
Examples
• Deblock using weak filter and block size of 4 pixels.
deblock=filter=weak:block=4
• Deblock using strong filter, block size of 4 pixels and custom thresholds for
deblocking more edges.
deblock=filter=strong:block=4:alpha=0.12:beta=0.07:gamma=0.06:delta=0.05
• Similar as above, but filter only first plane.
deblock=filter=strong:block=4:alpha=0.12:beta=0.07:gamma=0.06:delta=0.05:planes=1
• Similar as above, but filter only second and third plane.
deblock=filter=strong:block=4:alpha=0.12:beta=0.07:gamma=0.06:delta=0.05:planes=6
Commands
This filter supports the all above options as commands.
decimate
Drop duplicated frames at regular intervals.
The filter accepts the following options:
cycle
Set the number of frames from which one will be dropped. Setting this to N means one
frame in every batch of N frames will be dropped. Default is 5.
dupthresh
Set the threshold for duplicate detection. If the difference metric for a frame is
less than or equal to this value, then it is declared as duplicate. Default is 1.1
scthresh
Set scene change threshold. Default is 15.
blockx
blocky
Set the size of the x and y-axis blocks used during metric calculations. Larger
blocks give better noise suppression, but also give worse detection of small
movements. Must be a power of two. Default is 32.
ppsrc
Mark main input as a pre-processed input and activate clean source input stream. This
allows the input to be pre-processed with various filters to help the metrics
calculation while keeping the frame selection lossless. When set to 1, the first
stream is for the pre-processed input, and the second stream is the clean source from
where the kept frames are chosen. Default is 0.
chroma
Set whether or not chroma is considered in the metric calculations. Default is 1.
mixed
Set whether or not the input only partially contains content to be decimated. Default
is "false". If enabled video output stream will be in variable frame rate.
deconvolve
Apply 2D deconvolution of video stream in frequency domain using second stream as impulse.
The filter accepts the following options:
planes
Set which planes to process.
impulse
Set which impulse video frames will be processed, can be first or all. Default is all.
noise
Set noise when doing divisions. Default is 0.0000001. Useful when width and height are
not same and not power of 2 or if stream prior to convolving had noise.
The "deconvolve" filter also supports the framesync options.
dedot
Reduce cross-luminance (dot-crawl) and cross-color (rainbows) from video.
It accepts the following options:
m Set mode of operation. Can be combination of dotcrawl for cross-luminance reduction
and/or rainbows for cross-color reduction.
lt Set spatial luma threshold. Lower values increases reduction of cross-luminance.
tl Set tolerance for temporal luma. Higher values increases reduction of cross-luminance.
tc Set tolerance for chroma temporal variation. Higher values increases reduction of
cross-color.
ct Set temporal chroma threshold. Lower values increases reduction of cross-color.
deflate
Apply deflate effect to the video.
This filter replaces the pixel by the local(3x3) average by taking into account only
values lower than the pixel.
It accepts the following options:
threshold0
threshold1
threshold2
threshold3
Limit the maximum change for each plane, default is 65535. If 0, plane will remain
unchanged.
Commands
This filter supports the all above options as commands.
deflicker
Remove temporal frame luminance variations.
It accepts the following options:
size, s
Set moving-average filter size in frames. Default is 5. Allowed range is 2 - 129.
mode, m
Set averaging mode to smooth temporal luminance variations.
Available values are:
am Arithmetic mean
gm Geometric mean
hm Harmonic mean
qm Quadratic mean
cm Cubic mean
pm Power mean
median
Median
bypass
Do not actually modify frame. Useful when one only wants metadata.
dejudder
Remove judder produced by partially interlaced telecined content.
Judder can be introduced, for instance, by pullup filter. If the original source was
partially telecined content then the output of "pullup,dejudder" will have a variable
frame rate. May change the recorded frame rate of the container. Aside from that change,
this filter will not affect constant frame rate video.
The option available in this filter is:
cycle
Specify the length of the window over which the judder repeats.
Accepts any integer greater than 1. Useful values are:
4 If the original was telecined from 24 to 30 fps (Film to NTSC).
5 If the original was telecined from 25 to 30 fps (PAL to NTSC).
20 If a mixture of the two.
The default is 4.
delogo
Suppress a TV station logo by a simple interpolation of the surrounding pixels. Just set a
rectangle covering the logo and watch it disappear (and sometimes something even uglier
appear - your mileage may vary).
It accepts the following parameters:
x
y Specify the top left corner coordinates of the logo. They must be specified.
w
h Specify the width and height of the logo to clear. They must be specified.
show
When set to 1, a green rectangle is drawn on the screen to simplify finding the right
x, y, w, and h parameters. The default value is 0.
The rectangle is drawn on the outermost pixels which will be (partly) replaced with
interpolated values. The values of the next pixels immediately outside this rectangle
in each direction will be used to compute the interpolated pixel values inside the
rectangle.
Examples
• Set a rectangle covering the area with top left corner coordinates 0,0 and size
100x77:
delogo=x=0:y=0:w=100:h=77
derain
Remove the rain in the input image/video by applying the derain methods based on
convolutional neural networks. Supported models:
• Recurrent Squeeze-and-Excitation Context Aggregation Net (RESCAN). See
<http://openaccess.thecvf.com/content_ECCV_2018/papers/Xia_Li_Recurrent_Squeeze-and-Excitation_Context_ECCV_2018_paper.pdf>.
Training as well as model generation scripts are provided in the repository at
<https://github.com/XueweiMeng/derain_filter.git>.
The filter accepts the following options:
filter_type
Specify which filter to use. This option accepts the following values:
derain
Derain filter. To conduct derain filter, you need to use a derain model.
dehaze
Dehaze filter. To conduct dehaze filter, you need to use a dehaze model.
Default value is derain.
dnn_backend
Specify which DNN backend to use for model loading and execution. This option accepts
the following values:
tensorflow
TensorFlow backend. To enable this backend you need to install the TensorFlow for
C library (see <https://www.tensorflow.org/install/lang_c>) and configure FFmpeg
with "--enable-libtensorflow"
model
Set path to model file specifying network architecture and its parameters. Note that
different backends use different file formats. TensorFlow can load files for only its
format.
To get full functionality (such as async execution), please use the dnn_processing filter.
deshake
Attempt to fix small changes in horizontal and/or vertical shift. This filter helps remove
camera shake from hand-holding a camera, bumping a tripod, moving on a vehicle, etc.
The filter accepts the following options:
x
y
w
h Specify a rectangular area where to limit the search for motion vectors. If desired
the search for motion vectors can be limited to a rectangular area of the frame
defined by its top left corner, width and height. These parameters have the same
meaning as the drawbox filter which can be used to visualise the position of the
bounding box.
This is useful when simultaneous movement of subjects within the frame might be
confused for camera motion by the motion vector search.
If any or all of x, y, w and h are set to -1 then the full frame is used. This allows
later options to be set without specifying the bounding box for the motion vector
search.
Default - search the whole frame.
rx
ry Specify the maximum extent of movement in x and y directions in the range 0-64 pixels.
Default 16.
edge
Specify how to generate pixels to fill blanks at the edge of the frame. Available
values are:
blank, 0
Fill zeroes at blank locations
original, 1
Original image at blank locations
clamp, 2
Extruded edge value at blank locations
mirror, 3
Mirrored edge at blank locations
Default value is mirror.
blocksize
Specify the blocksize to use for motion search. Range 4-128 pixels, default 8.
contrast
Specify the contrast threshold for blocks. Only blocks with more than the specified
contrast (difference between darkest and lightest pixels) will be considered. Range
1-255, default 125.
search
Specify the search strategy. Available values are:
exhaustive, 0
Set exhaustive search
less, 1
Set less exhaustive search.
Default value is exhaustive.
filename
If set then a detailed log of the motion search is written to the specified file.
despill
Remove unwanted contamination of foreground colors, caused by reflected color of
greenscreen or bluescreen.
This filter accepts the following options:
type
Set what type of despill to use.
mix Set how spillmap will be generated.
expand
Set how much to get rid of still remaining spill.
red Controls amount of red in spill area.
green
Controls amount of green in spill area. Should be -1 for greenscreen.
blue
Controls amount of blue in spill area. Should be -1 for bluescreen.
brightness
Controls brightness of spill area, preserving colors.
alpha
Modify alpha from generated spillmap.
Commands
This filter supports the all above options as commands.
detelecine
Apply an exact inverse of the telecine operation. It requires a predefined pattern
specified using the pattern option which must be the same as that passed to the telecine
filter.
This filter accepts the following options:
first_field
top, t
top field first
bottom, b
bottom field first The default value is "top".
pattern
A string of numbers representing the pulldown pattern you wish to apply. The default
value is 23.
start_frame
A number representing position of the first frame with respect to the telecine
pattern. This is to be used if the stream is cut. The default value is 0.
dilation
Apply dilation effect to the video.
This filter replaces the pixel by the local(3x3) maximum.
It accepts the following options:
threshold0
threshold1
threshold2
threshold3
Limit the maximum change for each plane, default is 65535. If 0, plane will remain
unchanged.
coordinates
Flag which specifies the pixel to refer to. Default is 255 i.e. all eight pixels are
used.
Flags to local 3x3 coordinates maps like this:
1 2 3
4 5
6 7 8
Commands
This filter supports the all above options as commands.
displace
Displace pixels as indicated by second and third input stream.
It takes three input streams and outputs one stream, the first input is the source, and
second and third input are displacement maps.
The second input specifies how much to displace pixels along the x-axis, while the third
input specifies how much to displace pixels along the y-axis. If one of displacement map
streams terminates, last frame from that displacement map will be used.
Note that once generated, displacements maps can be reused over and over again.
A description of the accepted options follows.
edge
Set displace behavior for pixels that are out of range.
Available values are:
blank
Missing pixels are replaced by black pixels.
smear
Adjacent pixels will spread out to replace missing pixels.
wrap
Out of range pixels are wrapped so they point to pixels of other side.
mirror
Out of range pixels will be replaced with mirrored pixels.
Default is smear.
Examples
• Add ripple effect to rgb input of video size hd720:
ffmpeg -i INPUT -f lavfi -i nullsrc=s=hd720,lutrgb=128:128:128 -f lavfi -i nullsrc=s=hd720,geq='r=128+30*sin(2*PI*X/400+T):g=128+30*sin(2*PI*X/400+T):b=128+30*sin(2*PI*X/400+T)' -lavfi '[0][1][2]displace' OUTPUT
• Add wave effect to rgb input of video size hd720:
ffmpeg -i INPUT -f lavfi -i nullsrc=hd720,geq='r=128+80*(sin(sqrt((X-W/2)*(X-W/2)+(Y-H/2)*(Y-H/2))/220*2*PI+T)):g=128+80*(sin(sqrt((X-W/2)*(X-W/2)+(Y-H/2)*(Y-H/2))/220*2*PI+T)):b=128+80*(sin(sqrt((X-W/2)*(X-W/2)+(Y-H/2)*(Y-H/2))/220*2*PI+T))' -lavfi '[1]split[x][y],[0][x][y]displace' OUTPUT
dnn_classify
Do classification with deep neural networks based on bounding boxes.
The filter accepts the following options:
dnn_backend
Specify which DNN backend to use for model loading and execution. This option accepts
only openvino now, tensorflow backends will be added.
model
Set path to model file specifying network architecture and its parameters. Note that
different backends use different file formats.
input
Set the input name of the dnn network.
output
Set the output name of the dnn network.
confidence
Set the confidence threshold (default: 0.5).
labels
Set path to label file specifying the mapping between label id and name. Each label
name is written in one line, tailing spaces and empty lines are skipped. The first
line is the name of label id 0, and the second line is the name of label id 1, etc.
The label id is considered as name if the label file is not provided.
backend_configs
Set the configs to be passed into backend
For tensorflow backend, you can set its configs with sess_config options, please use
tools/python/tf_sess_config.py to get the configs for your system.
dnn_detect
Do object detection with deep neural networks.
The filter accepts the following options:
dnn_backend
Specify which DNN backend to use for model loading and execution. This option accepts
only openvino now, tensorflow backends will be added.
model
Set path to model file specifying network architecture and its parameters. Note that
different backends use different file formats.
input
Set the input name of the dnn network.
output
Set the output name of the dnn network.
confidence
Set the confidence threshold (default: 0.5).
labels
Set path to label file specifying the mapping between label id and name. Each label
name is written in one line, tailing spaces and empty lines are skipped. The first
line is the name of label id 0 (usually it is 'background'), and the second line is
the name of label id 1, etc. The label id is considered as name if the label file is
not provided.
backend_configs
Set the configs to be passed into backend. To use async execution, set async (default:
set). Roll back to sync execution if the backend does not support async.
dnn_processing
Do image processing with deep neural networks. It works together with another filter which
converts the pixel format of the Frame to what the dnn network requires.
The filter accepts the following options:
dnn_backend
Specify which DNN backend to use for model loading and execution. This option accepts
the following values:
tensorflow
TensorFlow backend. To enable this backend you need to install the TensorFlow for
C library (see <https://www.tensorflow.org/install/lang_c>) and configure FFmpeg
with "--enable-libtensorflow"
openvino
OpenVINO backend. To enable this backend you need to build and install the
OpenVINO for C library (see
<https://github.com/openvinotoolkit/openvino/blob/master/build-instruction.md>)
and configure FFmpeg with "--enable-libopenvino" (--extra-cflags=-I...
--extra-ldflags=-L... might be needed if the header files and libraries are not
installed into system path)
torch
Libtorch backend. To enable this backend you need to build and install Libtroch
for C++ library. Please download cxx11 ABI version (see
<https://pytorch.org/get-started/locally>) and configure FFmpeg with
"--enable-libtorch --extra-cflags=-I/libtorch_root/libtorch/include
--extra-cflags=-I/libtorch_root/libtorch/include/torch/csrc/api/include
--extra-ldflags=-L/libtorch_root/libtorch/lib/"
model
Set path to model file specifying network architecture and its parameters. Note that
different backends use different file formats. TensorFlow, OpenVINO and Libtorch
backend can load files for only its format.
input
Set the input name of the dnn network.
output
Set the output name of the dnn network.
backend_configs
Set the configs to be passed into backend. To use async execution, set async (default:
set). Roll back to sync execution if the backend does not support async.
For tensorflow backend, you can set its configs with sess_config options, please use
tools/python/tf_sess_config.py to get the configs of TensorFlow backend for your
system.
Examples
• Remove rain in rgb24 frame with can.pb (see derain filter):
./ffmpeg -i rain.jpg -vf format=rgb24,dnn_processing=dnn_backend=tensorflow:model=can.pb:input=x:output=y derain.jpg
• Handle the Y channel with srcnn.pb (see sr filter) for frame with yuv420p (planar YUV
formats supported):
./ffmpeg -i 480p.jpg -vf format=yuv420p,scale=w=iw*2:h=ih*2,dnn_processing=dnn_backend=tensorflow:model=srcnn.pb:input=x:output=y -y srcnn.jpg
• Handle the Y channel with espcn.pb (see sr filter), which changes frame size, for
format yuv420p (planar YUV formats supported), please use
tools/python/tf_sess_config.py to get the configs of TensorFlow backend for your
system.
./ffmpeg -i 480p.jpg -vf format=yuv420p,dnn_processing=dnn_backend=tensorflow:model=espcn.pb:input=x:output=y:backend_configs=sess_config=0x10022805320e09cdccccccccccec3f20012a01303801 -y tmp.espcn.jpg
drawbox
Draw a colored box on the input image.
It accepts the following parameters:
x
y The expressions which specify the top left corner coordinates of the box. It defaults
to 0.
width, w
height, h
The expressions which specify the width and height of the box; if 0 they are
interpreted as the input width and height. It defaults to 0.
color, c
Specify the color of the box to write. For the general syntax of this option, check
the "Color" section in the ffmpeg-utils manual. If the special value "invert" is used,
the box edge color is the same as the video with inverted luma.
thickness, t
The expression which sets the thickness of the box edge. A value of "fill" will
create a filled box. Default value is 3.
See below for the list of accepted constants.
replace
Applicable if the input has alpha. With value 1, the pixels of the painted box will
overwrite the video's color and alpha pixels. Default is 0, which composites the box
onto the input, leaving the video's alpha intact.
The parameters for x, y, w and h and t are expressions containing the following constants:
dar The input display aspect ratio, it is the same as (w / h) * sar.
hsub
vsub
horizontal and vertical chroma subsample values. For example for the pixel format
"yuv422p" hsub is 2 and vsub is 1.
in_h, ih
in_w, iw
The input width and height.
sar The input sample aspect ratio.
x
y The x and y offset coordinates where the box is drawn.
w
h The width and height of the drawn box.
box_source
Box source can be set as side_data_detection_bboxes if you want to use box data in
detection bboxes of side data.
If box_source is set, the x, y, width and height will be ignored and still use box
data in detection bboxes of side data. So please do not use this parameter if you were
not sure about the box source.
t The thickness of the drawn box.
These constants allow the x, y, w, h and t expressions to refer to each other, so you
may for example specify "y=x/dar" or "h=w/dar".
Examples
• Draw a black box around the edge of the input image:
drawbox
• Draw a box with color red and an opacity of 50%:
drawbox=10:20:200:60:red@0.5
The previous example can be specified as:
drawbox=x=10:y=20:w=200:h=60:color=red@0.5
• Fill the box with pink color:
drawbox=x=10:y=10:w=100:h=100:color=pink@0.5:t=fill
• Draw a 2-pixel red 2.40:1 mask:
drawbox=x=-t:y=0.5*(ih-iw/2.4)-t:w=iw+t*2:h=iw/2.4+t*2:t=2:c=red
Commands
This filter supports same commands as options. The command accepts the same syntax of the
corresponding option.
If the specified expression is not valid, it is kept at its current value.
drawgraph
Draw a graph using input video metadata.
It accepts the following parameters:
m1 Set 1st frame metadata key from which metadata values will be used to draw a graph.
fg1 Set 1st foreground color expression.
m2 Set 2nd frame metadata key from which metadata values will be used to draw a graph.
fg2 Set 2nd foreground color expression.
m3 Set 3rd frame metadata key from which metadata values will be used to draw a graph.
fg3 Set 3rd foreground color expression.
m4 Set 4th frame metadata key from which metadata values will be used to draw a graph.
fg4 Set 4th foreground color expression.
min Set minimal value of metadata value.
max Set maximal value of metadata value.
bg Set graph background color. Default is white.
mode
Set graph mode.
Available values for mode is:
bar
dot
line
Default is "line".
slide
Set slide mode.
Available values for slide is:
frame
Draw new frame when right border is reached.
replace
Replace old columns with new ones.
scroll
Scroll from right to left.
rscroll
Scroll from left to right.
picture
Draw single picture.
Default is "frame".
size
Set size of graph video. For the syntax of this option, check the "Video size" section
in the ffmpeg-utils manual. The default value is "900x256".
rate, r
Set the output frame rate. Default value is 25.
The foreground color expressions can use the following variables:
MIN Minimal value of metadata value.
MAX Maximal value of metadata value.
VAL Current metadata key value.
The color is defined as 0xAABBGGRR.
Example using metadata from signalstats filter:
signalstats,drawgraph=lavfi.signalstats.YAVG:min=0:max=255
Example using metadata from ebur128 filter:
ebur128=metadata=1,adrawgraph=lavfi.r128.M:min=-120:max=5
drawgrid
Draw a grid on the input image.
It accepts the following parameters:
x
y The expressions which specify the coordinates of some point of grid intersection
(meant to configure offset). Both default to 0.
width, w
height, h
The expressions which specify the width and height of the grid cell, if 0 they are
interpreted as the input width and height, respectively, minus "thickness", so image
gets framed. Default to 0.
color, c
Specify the color of the grid. For the general syntax of this option, check the
"Color" section in the ffmpeg-utils manual. If the special value "invert" is used, the
grid color is the same as the video with inverted luma.
thickness, t
The expression which sets the thickness of the grid line. Default value is 1.
See below for the list of accepted constants.
replace
Applicable if the input has alpha. With 1 the pixels of the painted grid will
overwrite the video's color and alpha pixels. Default is 0, which composites the grid
onto the input, leaving the video's alpha intact.
The parameters for x, y, w and h and t are expressions containing the following constants:
dar The input display aspect ratio, it is the same as (w / h) * sar.
hsub
vsub
horizontal and vertical chroma subsample values. For example for the pixel format
"yuv422p" hsub is 2 and vsub is 1.
in_h, ih
in_w, iw
The input grid cell width and height.
sar The input sample aspect ratio.
x
y The x and y coordinates of some point of grid intersection (meant to configure
offset).
w
h The width and height of the drawn cell.
t The thickness of the drawn cell.
These constants allow the x, y, w, h and t expressions to refer to each other, so you
may for example specify "y=x/dar" or "h=w/dar".
Examples
• Draw a grid with cell 100x100 pixels, thickness 2 pixels, with color red and an
opacity of 50%:
drawgrid=width=100:height=100:thickness=2:color=red@0.5
• Draw a white 3x3 grid with an opacity of 50%:
drawgrid=w=iw/3:h=ih/3:t=2:c=white@0.5
Commands
This filter supports same commands as options. The command accepts the same syntax of the
corresponding option.
If the specified expression is not valid, it is kept at its current value.
drawtext
Draw a text string or text from a specified file on top of a video, using the libfreetype
library.
To enable compilation of this filter, you need to configure FFmpeg with
"--enable-libfreetype" and "--enable-libharfbuzz". To enable default font fallback and
the font option you need to configure FFmpeg with "--enable-libfontconfig". To enable the
text_shaping option, you need to configure FFmpeg with "--enable-libfribidi".
Syntax
It accepts the following parameters:
box Used to draw a box around text using the background color. The value must be either 1
(enable) or 0 (disable). The default value of box is 0.
boxborderw
Set the width of the border to be drawn around the box using boxcolor. The value must
be specified using one of the following formats:
*<"boxborderw=10" set the width of all the borders to 10>
*<"boxborderw=10|20" set the width of the top and bottom borders to 10>
and the width of the left and right borders to 20
*<"boxborderw=10|20|30" set the width of the top border to 10, the width>
of the bottom border to 30 and the width of the left and right borders to 20
*<"boxborderw=10|20|30|40" set the borders width to 10 (top), 20 (right),>
30 (bottom), 40 (left)
The default value of boxborderw is "0".
boxcolor
The color to be used for drawing box around text. For the syntax of this option, check
the "Color" section in the ffmpeg-utils manual.
The default value of boxcolor is "white".
line_spacing
Set the line spacing in pixels. The default value of line_spacing is 0.
text_align
Set the vertical and horizontal alignment of the text with respect to the box
boundaries. The value is combination of flags, one for the vertical alignment (T=top,
M=middle, B=bottom) and one for the horizontal alignment (L=left, C=center, R=right).
Please note that tab characters are only supported with the left horizontal alignment.
y_align
Specify what the y value is referred to. Possible values are:
*<"text" the top of the highest glyph of the first text line is placed at y>
*<"baseline" the baseline of the first text line is placed at y>
*<"font" the baseline of the first text line is placed at y plus the>
ascent (in pixels) defined in the font metrics
The default value of y_align is "text" for backward compatibility.
borderw
Set the width of the border to be drawn around the text using bordercolor. The
default value of borderw is 0.
bordercolor
Set the color to be used for drawing border around text. For the syntax of this
option, check the "Color" section in the ffmpeg-utils manual.
The default value of bordercolor is "black".
expansion
Select how the text is expanded. Can be either "none", "strftime" (deprecated) or
"normal" (default). See the drawtext_expansion, Text expansion section below for
details.
basetime
Set a start time for the count. Value is in microseconds. Only applied in the
deprecated "strftime" expansion mode. To emulate in normal expansion mode use the
"pts" function, supplying the start time (in seconds) as the second argument.
fix_bounds
If true, check and fix text coords to avoid clipping.
fontcolor
The color to be used for drawing fonts. For the syntax of this option, check the
"Color" section in the ffmpeg-utils manual.
The default value of fontcolor is "black".
fontcolor_expr
String which is expanded the same way as text to obtain dynamic fontcolor value. By
default this option has empty value and is not processed. When this option is set, it
overrides fontcolor option.
font
The font family to be used for drawing text. By default Sans.
fontfile
The font file to be used for drawing text. The path must be included. This parameter
is mandatory if the fontconfig support is disabled.
alpha
Draw the text applying alpha blending. The value can be a number between 0.0 and 1.0.
The expression accepts the same variables x, y as well. The default value is 1.
Please see fontcolor_expr.
fontsize
The font size to be used for drawing text. The default value of fontsize is 16.
text_shaping
If set to 1, attempt to shape the text (for example, reverse the order of right-to-
left text and join Arabic characters) before drawing it. Otherwise, just draw the
text exactly as given. By default 1 (if supported).
ft_load_flags
The flags to be used for loading the fonts.
The flags map the corresponding flags supported by libfreetype, and are a combination
of the following values:
default
no_scale
no_hinting
render
no_bitmap
vertical_layout
force_autohint
crop_bitmap
pedantic
ignore_global_advance_width
no_recurse
ignore_transform
monochrome
linear_design
no_autohint
Default value is "default".
For more information consult the documentation for the FT_LOAD_* libfreetype flags.
shadowcolor
The color to be used for drawing a shadow behind the drawn text. For the syntax of
this option, check the "Color" section in the ffmpeg-utils manual.
The default value of shadowcolor is "black".
boxw
Set the width of the box to be drawn around text. The default value of boxw is
computed automatically to match the text width
boxh
Set the height of the box to be drawn around text. The default value of boxh is
computed automatically to match the text height
shadowx
shadowy
The x and y offsets for the text shadow position with respect to the position of the
text. They can be either positive or negative values. The default value for both is
"0".
start_number
The starting frame number for the n/frame_num variable. The default value is "0".
tabsize
The size in number of spaces to use for rendering the tab. Default value is 4.
timecode
Set the initial timecode representation in "hh:mm:ss[:;.]ff" format. It can be used
with or without text parameter. timecode_rate option must be specified.
timecode_rate, rate, r
Set the timecode frame rate (timecode only). Value will be rounded to nearest integer.
Minimum value is "1". Drop-frame timecode is supported for frame rates 30 & 60.
tc24hmax
If set to 1, the output of the timecode option will wrap around at 24 hours. Default
is 0 (disabled).
text
The text string to be drawn. The text must be a sequence of UTF-8 encoded characters.
This parameter is mandatory if no file is specified with the parameter textfile.
textfile
A text file containing text to be drawn. The text must be a sequence of UTF-8 encoded
characters.
This parameter is mandatory if no text string is specified with the parameter text.
If both text and textfile are specified, an error is thrown.
text_source
Text source should be set as side_data_detection_bboxes if you want to use text data
in detection bboxes of side data.
If text source is set, text and textfile will be ignored and still use text data in
detection bboxes of side data. So please do not use this parameter if you are not sure
about the text source.
reload
The textfile will be reloaded at specified frame interval. Be sure to update textfile
atomically, or it may be read partially, or even fail. Range is 0 to INT_MAX. Default
is 0.
x
y The expressions which specify the offsets where text will be drawn within the video
frame. They are relative to the top/left border of the output image.
The default value of x and y is "0".
See below for the list of accepted constants and functions.
The parameters for x and y are expressions containing the following constants and
functions:
dar input display aspect ratio, it is the same as (w / h) * sar
hsub
vsub
horizontal and vertical chroma subsample values. For example for the pixel format
"yuv422p" hsub is 2 and vsub is 1.
line_h, lh
the height of each text line
main_h, h, H
the input height
main_w, w, W
the input width
max_glyph_a, ascent
the maximum distance from the baseline to the highest/upper grid coordinate used to
place a glyph outline point, for all the rendered glyphs. It is a positive value, due
to the grid's orientation with the Y axis upwards.
max_glyph_d, descent
the maximum distance from the baseline to the lowest grid coordinate used to place a
glyph outline point, for all the rendered glyphs. This is a negative value, due to
the grid's orientation, with the Y axis upwards.
max_glyph_h
maximum glyph height, that is the maximum height for all the glyphs contained in the
rendered text, it is equivalent to ascent - descent.
max_glyph_w
maximum glyph width, that is the maximum width for all the glyphs contained in the
rendered text
font_a
the ascent size defined in the font metrics
font_d
the descent size defined in the font metrics
top_a
the maximum ascender of the glyphs of the first text line
bottom_d
the maximum descender of the glyphs of the last text line
n the number of input frame, starting from 0
rand(min, max)
return a random number included between min and max
sar The input sample aspect ratio.
t timestamp expressed in seconds, NAN if the input timestamp is unknown
text_h, th
the height of the rendered text
text_w, tw
the width of the rendered text
x
y the x and y offset coordinates where the text is drawn.
These parameters allow the x and y expressions to refer to each other, so you can for
example specify "y=x/dar".
pict_type
A one character description of the current frame's picture type.
pkt_pos
The current packet's position in the input file or stream (in bytes, from the start of
the input). A value of -1 indicates this info is not available.
duration
The current packet's duration, in seconds.
pkt_size
The current packet's size (in bytes).
Text expansion
If expansion is set to "strftime", the filter recognizes sequences accepted by the
"strftime" C function in the provided text and expands them accordingly. Check the
documentation of "strftime". This feature is deprecated in favor of "normal" expansion
with the "gmtime" or "localtime" expansion functions.
If expansion is set to "none", the text is printed verbatim.
If expansion is set to "normal" (which is the default), the following expansion mechanism
is used.
The backslash character \, followed by any character, always expands to the second
character.
Sequences of the form "%{...}" are expanded. The text between the braces is a function
name, possibly followed by arguments separated by ':'. If the arguments contain special
characters or delimiters (':' or '}'), they should be escaped.
Note that they probably must also be escaped as the value for the text option in the
filter argument string and as the filter argument in the filtergraph description, and
possibly also for the shell, that makes up to four levels of escaping; using a text file
with the textfile option avoids these problems.
The following functions are available:
expr, e
The expression evaluation result.
It must take one argument specifying the expression to be evaluated, which accepts the
same constants and functions as the x and y values. Note that not all constants should
be used, for example the text size is not known when evaluating the expression, so the
constants text_w and text_h will have an undefined value.
expr_int_format, eif
Evaluate the expression's value and output as formatted integer.
The first argument is the expression to be evaluated, just as for the expr function.
The second argument specifies the output format. Allowed values are x, X, d and u.
They are treated exactly as in the "printf" function. The third parameter is optional
and sets the number of positions taken by the output. It can be used to add padding
with zeros from the left.
gmtime
The time at which the filter is running, expressed in UTC. It can accept an argument:
a "strftime" C function format string. The format string is extended to support the
variable %[1-6]N which prints fractions of the second with optionally specified number
of digits.
localtime
The time at which the filter is running, expressed in the local time zone. It can
accept an argument: a "strftime" C function format string. The format string is
extended to support the variable %[1-6]N which prints fractions of the second with
optionally specified number of digits.
metadata
Frame metadata. Takes one or two arguments.
The first argument is mandatory and specifies the metadata key.
The second argument is optional and specifies a default value, used when the metadata
key is not found or empty.
Available metadata can be identified by inspecting entries starting with TAG included
within each frame section printed by running "ffprobe -show_frames".
String metadata generated in filters leading to the drawtext filter are also
available.
n, frame_num
The frame number, starting from 0.
pict_type
A one character description of the current picture type.
pts The timestamp of the current frame. It can take up to three arguments.
The first argument is the format of the timestamp; it defaults to "flt" for seconds as
a decimal number with microsecond accuracy; "hms" stands for a formatted
[-]HH:MM:SS.mmm timestamp with millisecond accuracy. "gmtime" stands for the
timestamp of the frame formatted as UTC time; "localtime" stands for the timestamp of
the frame formatted as local time zone time.
The second argument is an offset added to the timestamp.
If the format is set to "hms", a third argument "24HH" may be supplied to present the
hour part of the formatted timestamp in 24h format (00-23).
If the format is set to "localtime" or "gmtime", a third argument may be supplied: a
"strftime" C function format string. By default, YYYY-MM-DD HH:MM:SS format will be
used.
Commands
This filter supports altering parameters via commands:
reinit
Alter existing filter parameters.
Syntax for the argument is the same as for filter invocation, e.g.
fontsize=56:fontcolor=green:text='Hello World'
Full filter invocation with sendcmd would look like this:
sendcmd=c='56.0 drawtext reinit fontsize=56\:fontcolor=green\:text=Hello\\ World'
If the entire argument can't be parsed or applied as valid values then the filter will
continue with its existing parameters.
The following options are also supported as commands:
*<x>
*<y>
*<alpha>
*<fontsize>
*<fontcolor>
*<boxcolor>
*<bordercolor>
*<shadowcolor>
*<box>
*<boxw>
*<boxh>
*<boxborderw>
*<line_spacing>
*<text_align>
*<shadowx>
*<shadowy>
*<borderw>
Examples
• Draw "Test Text" with font FreeSerif, using the default values for the optional
parameters.
drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text'"
• Draw 'Test Text' with font FreeSerif of size 24 at position x=100 and y=50 (counting
from the top-left corner of the screen), text is yellow with a red box around it. Both
the text and the box have an opacity of 20%.
drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text':\
x=100: y=50: fontsize=24: fontcolor=yellow@0.2: box=1: boxcolor=red@0.2"
Note that the double quotes are not necessary if spaces are not used within the
parameter list.
• Show the text at the center of the video frame:
drawtext="fontsize=30:fontfile=FreeSerif.ttf:text='hello world':x=(w-text_w)/2:y=(h-text_h)/2"
• Show the text at a random position, switching to a new position every 30 seconds:
drawtext="fontsize=30:fontfile=FreeSerif.ttf:text='hello world':x=if(eq(mod(t\,30)\,0)\,rand(0\,(w-text_w))\,x):y=if(eq(mod(t\,30)\,0)\,rand(0\,(h-text_h))\,y)"
• Show a text line sliding from right to left in the last row of the video frame. The
file LONG_LINE is assumed to contain a single line with no newlines.
drawtext="fontsize=15:fontfile=FreeSerif.ttf:text=LONG_LINE:y=h-line_h:x=-50*t"
• Show the content of file CREDITS off the bottom of the frame and scroll up.
drawtext="fontsize=20:fontfile=FreeSerif.ttf:textfile=CREDITS:y=h-20*t"
• Draw a single green letter "g", at the center of the input video. The glyph baseline
is placed at half screen height.
drawtext="fontsize=60:fontfile=FreeSerif.ttf:fontcolor=green:text=g:x=(w-max_glyph_w)/2:y=h/2-ascent"
• Show text for 1 second every 3 seconds:
drawtext="fontfile=FreeSerif.ttf:fontcolor=white:x=100:y=x/dar:enable=lt(mod(t\,3)\,1):text='blink'"
• Use fontconfig to set the font. Note that the colons need to be escaped.
drawtext='fontfile=Linux Libertine O-40\\:style=Semibold:text=FFmpeg'
• Draw "Test Text" with font size dependent on height of the video.
drawtext="text='Test Text': fontsize=h/30: x=(w-text_w)/2: y=(h-text_h*2)"
• Print the date of a real-time encoding (see documentation for the "strftime" C
function):
drawtext='fontfile=FreeSans.ttf:text=%{localtime\:%a %b %d %Y}'
• Show text fading in and out (appearing/disappearing):
#!/bin/sh
DS=1.0 # display start
DE=10.0 # display end
FID=1.5 # fade in duration
FOD=5 # fade out duration
ffplay -f lavfi "color,drawtext=text=TEST:fontsize=50:fontfile=FreeSerif.ttf:fontcolor_expr=ff0000%{eif\\\\: clip(255*(1*between(t\\, $DS + $FID\\, $DE - $FOD) + ((t - $DS)/$FID)*between(t\\, $DS\\, $DS + $FID) + (-(t - $DE)/$FOD)*between(t\\, $DE - $FOD\\, $DE) )\\, 0\\, 255) \\\\: x\\\\: 2 }"
• Horizontally align multiple separate texts. Note that max_glyph_a and the fontsize
value are included in the y offset.
drawtext=fontfile=FreeSans.ttf:text=DOG:fontsize=24:x=10:y=20+24-max_glyph_a,
drawtext=fontfile=FreeSans.ttf:text=cow:fontsize=24:x=80:y=20+24-max_glyph_a
• Plot special lavf.image2dec.source_basename metadata onto each frame if such metadata
exists. Otherwise, plot the string "NA". Note that image2 demuxer must have option
-export_path_metadata 1 for the special metadata fields to be available for filters.
drawtext="fontsize=20:fontcolor=white:fontfile=FreeSans.ttf:text='%{metadata\:lavf.image2dec.source_basename\:NA}':x=10:y=10"
For more information about libfreetype, check: <http://www.freetype.org/>.
For more information about fontconfig, check:
<http://freedesktop.org/software/fontconfig/fontconfig-user.html>.
For more information about libfribidi, check: <http://fribidi.org/>.
For more information about libharfbuzz, check: <https://github.com/harfbuzz/harfbuzz>.
edgedetect
Detect and draw edges. The filter uses the Canny Edge Detection algorithm.
The filter accepts the following options:
low
high
Set low and high threshold values used by the Canny thresholding algorithm.
The high threshold selects the "strong" edge pixels, which are then connected through
8-connectivity with the "weak" edge pixels selected by the low threshold.
low and high threshold values must be chosen in the range [0,1], and low should be
lesser or equal to high.
Default value for low is "20/255", and default value for high is "50/255".
mode
Define the drawing mode.
wires
Draw white/gray wires on black background.
colormix
Mix the colors to create a paint/cartoon effect.
canny
Apply Canny edge detector on all selected planes.
Default value is wires.
planes
Select planes for filtering. By default all available planes are filtered.
Examples
• Standard edge detection with custom values for the hysteresis thresholding:
edgedetect=low=0.1:high=0.4
• Painting effect without thresholding:
edgedetect=mode=colormix:high=0
elbg
Apply a posterize effect using the ELBG (Enhanced LBG) algorithm.
For each input image, the filter will compute the optimal mapping from the input to the
output given the codebook length, that is the number of distinct output colors.
This filter accepts the following options.
codebook_length, l
Set codebook length. The value must be a positive integer, and represents the number
of distinct output colors. Default value is 256.
nb_steps, n
Set the maximum number of iterations to apply for computing the optimal mapping. The
higher the value the better the result and the higher the computation time. Default
value is 1.
seed, s
Set a random seed, must be an integer included between 0 and UINT32_MAX. If not
specified, or if explicitly set to -1, the filter will try to use a good random seed
on a best effort basis.
pal8
Set pal8 output pixel format. This option does not work with codebook length greater
than 256. Default is disabled.
use_alpha
Include alpha values in the quantization calculation. Allows creating palettized
output images (e.g. PNG8) with multiple alpha smooth blending.
entropy
Measure graylevel entropy in histogram of color channels of video frames.
It accepts the following parameters:
mode
Can be either normal or diff. Default is normal.
diff mode measures entropy of histogram delta values, absolute differences between
neighbour histogram values.
epx
Apply the EPX magnification filter which is designed for pixel art.
It accepts the following option:
n Set the scaling dimension: 2 for "2xEPX", 3 for "3xEPX". Default is 3.
eq
Set brightness, contrast, saturation and approximate gamma adjustment.
The filter accepts the following options:
contrast
Set the contrast expression. The value must be a float value in range -1000.0 to
1000.0. The default value is "1".
brightness
Set the brightness expression. The value must be a float value in range -1.0 to 1.0.
The default value is "0".
saturation
Set the saturation expression. The value must be a float in range 0.0 to 3.0. The
default value is "1".
gamma
Set the gamma expression. The value must be a float in range 0.1 to 10.0. The default
value is "1".
gamma_r
Set the gamma expression for red. The value must be a float in range 0.1 to 10.0. The
default value is "1".
gamma_g
Set the gamma expression for green. The value must be a float in range 0.1 to 10.0.
The default value is "1".
gamma_b
Set the gamma expression for blue. The value must be a float in range 0.1 to 10.0. The
default value is "1".
gamma_weight
Set the gamma weight expression. It can be used to reduce the effect of a high gamma
value on bright image areas, e.g. keep them from getting overamplified and just plain
white. The value must be a float in range 0.0 to 1.0. A value of 0.0 turns the gamma
correction all the way down while 1.0 leaves it at its full strength. Default is "1".
eval
Set when the expressions for brightness, contrast, saturation and gamma expressions
are evaluated.
It accepts the following values:
init
only evaluate expressions once during the filter initialization or when a command
is processed
frame
evaluate expressions for each incoming frame
Default value is init.
The expressions accept the following parameters:
n frame count of the input frame starting from 0
pos byte position of the corresponding packet in the input file, NAN if unspecified;
deprecated, do not use
r frame rate of the input video, NAN if the input frame rate is unknown
t timestamp expressed in seconds, NAN if the input timestamp is unknown
Commands
The filter supports the following commands:
contrast
Set the contrast expression.
brightness
Set the brightness expression.
saturation
Set the saturation expression.
gamma
Set the gamma expression.
gamma_r
Set the gamma_r expression.
gamma_g
Set gamma_g expression.
gamma_b
Set gamma_b expression.
gamma_weight
Set gamma_weight expression.
The command accepts the same syntax of the corresponding option.
If the specified expression is not valid, it is kept at its current value.
erosion
Apply erosion effect to the video.
This filter replaces the pixel by the local(3x3) minimum.
It accepts the following options:
threshold0
threshold1
threshold2
threshold3
Limit the maximum change for each plane, default is 65535. If 0, plane will remain
unchanged.
coordinates
Flag which specifies the pixel to refer to. Default is 255 i.e. all eight pixels are
used.
Flags to local 3x3 coordinates maps like this:
1 2 3
4 5
6 7 8
Commands
This filter supports the all above options as commands.
estdif
Deinterlace the input video ("estdif" stands for "Edge Slope Tracing Deinterlacing
Filter").
Spatial only filter that uses edge slope tracing algorithm to interpolate missing lines.
It accepts the following parameters:
mode
The interlacing mode to adopt. It accepts one of the following values:
frame
Output one frame for each frame.
field
Output one frame for each field.
The default value is "field".
parity
The picture field parity assumed for the input interlaced video. It accepts one of the
following values:
tff Assume the top field is first.
bff Assume the bottom field is first.
auto
Enable automatic detection of field parity.
The default value is "auto". If the interlacing is unknown or the decoder does not
export this information, top field first will be assumed.
deint
Specify which frames to deinterlace. Accepts one of the following values:
all Deinterlace all frames.
interlaced
Only deinterlace frames marked as interlaced.
The default value is "all".
rslope
Specify the search radius for edge slope tracing. Default value is 1. Allowed range
is from 1 to 15.
redge
Specify the search radius for best edge matching. Default value is 2. Allowed range
is from 0 to 15.
ecost
Specify the edge cost for edge matching. Default value is 2. Allowed range is from 0
to 50.
mcost
Specify the middle cost for edge matching. Default value is 1. Allowed range is from
0 to 50.
dcost
Specify the distance cost for edge matching. Default value is 1. Allowed range is
from 0 to 50.
interp
Specify the interpolation used. Default is 4-point interpolation. It accepts one of
the following values:
2p Two-point interpolation.
4p Four-point interpolation.
6p Six-point interpolation.
Commands
This filter supports same commands as options.
exposure
Adjust exposure of the video stream.
The filter accepts the following options:
exposure
Set the exposure correction in EV. Allowed range is from -3.0 to 3.0 EV Default value
is 0 EV.
black
Set the black level correction. Allowed range is from -1.0 to 1.0. Default value is
0.
Commands
This filter supports same commands as options.
extractplanes
Extract color channel components from input video stream into separate grayscale video
streams.
The filter accepts the following option:
planes
Set plane(s) to extract.
Available values for planes are:
y
u
v
a
r
g
b
Choosing planes not available in the input will result in an error. That means you
cannot select "r", "g", "b" planes with "y", "u", "v" planes at same time.
Examples
• Extract luma, u and v color channel component from input video frame into 3 grayscale
outputs:
ffmpeg -i video.avi -filter_complex 'extractplanes=y+u+v[y][u][v]' -map '[y]' y.avi -map '[u]' u.avi -map '[v]' v.avi
fade
Apply a fade-in/out effect to the input video.
It accepts the following parameters:
type, t
The effect type can be either "in" for a fade-in, or "out" for a fade-out effect.
Default is "in".
start_frame, s
Specify the number of the frame to start applying the fade effect at. Default is 0.
nb_frames, n
The number of frames that the fade effect lasts. At the end of the fade-in effect, the
output video will have the same intensity as the input video. At the end of the fade-
out transition, the output video will be filled with the selected color. Default is
25.
alpha
If set to 1, fade only alpha channel, if one exists on the input. Default value is 0.
start_time, st
Specify the timestamp (in seconds) of the frame to start to apply the fade effect. If
both start_frame and start_time are specified, the fade will start at whichever comes
last. Default is 0.
duration, d
The number of seconds for which the fade effect has to last. At the end of the fade-in
effect the output video will have the same intensity as the input video, at the end of
the fade-out transition the output video will be filled with the selected color. If
both duration and nb_frames are specified, duration is used. Default is 0 (nb_frames
is used by default).
color, c
Specify the color of the fade. Default is "black".
Examples
• Fade in the first 30 frames of video:
fade=in:0:30
The command above is equivalent to:
fade=t=in:s=0:n=30
• Fade out the last 45 frames of a 200-frame video:
fade=out:155:45
fade=type=out:start_frame=155:nb_frames=45
• Fade in the first 25 frames and fade out the last 25 frames of a 1000-frame video:
fade=in:0:25, fade=out:975:25
• Make the first 5 frames yellow, then fade in from frame 5-24:
fade=in:5:20:color=yellow
• Fade in alpha over first 25 frames of video:
fade=in:0:25:alpha=1
• Make the first 5.5 seconds black, then fade in for 0.5 seconds:
fade=t=in:st=5.5:d=0.5
feedback
Apply feedback video filter.
This filter pass cropped input frames to 2nd output. From there it can be filtered with
other video filters. After filter receives frame from 2nd input, that frame is combined
on top of original frame from 1st input and passed to 1st output.
The typical usage is filter only part of frame.
The filter accepts the following options:
x
y Set the top left crop position.
w
h Set the crop size.
Examples
• Blur only top left rectangular part of video frame size 100x100 with gblur filter.
[in][blurin]feedback=x=0:y=0:w=100:h=100[out][blurout];[blurout]gblur=8[blurin]
• Draw black box on top left part of video frame of size 100x100 with drawbox filter.
[in][blurin]feedback=x=0:y=0:w=100:h=100[out][blurout];[blurout]drawbox=x=0:y=0:w=100:h=100:t=100[blurin]
• Pixelize rectangular part of video frame of size 100x100 with pixelize filter.
[in][blurin]feedback=x=320:y=240:w=100:h=100[out][blurout];[blurout]pixelize[blurin]
fftdnoiz
Denoise frames using 3D FFT (frequency domain filtering).
The filter accepts the following options:
sigma
Set the noise sigma constant. This sets denoising strength. Default value is 1.
Allowed range is from 0 to 30. Using very high sigma with low overlap may give
blocking artifacts.
amount
Set amount of denoising. By default all detected noise is reduced. Default value is
1. Allowed range is from 0 to 1.
block
Set size of block in pixels, Default is 32, can be 8 to 256.
overlap
Set block overlap. Default is 0.5. Allowed range is from 0.2 to 0.8.
method
Set denoising method. Default is "wiener", can also be "hard".
prev
Set number of previous frames to use for denoising. By default is set to 0.
next
Set number of next frames to to use for denoising. By default is set to 0.
planes
Set planes which will be filtered, by default are all available filtered except alpha.
fftfilt
Apply arbitrary expressions to samples in frequency domain
dc_Y
Adjust the dc value (gain) of the luma plane of the image. The filter accepts an
integer value in range 0 to 1000. The default value is set to 0.
dc_U
Adjust the dc value (gain) of the 1st chroma plane of the image. The filter accepts an
integer value in range 0 to 1000. The default value is set to 0.
dc_V
Adjust the dc value (gain) of the 2nd chroma plane of the image. The filter accepts an
integer value in range 0 to 1000. The default value is set to 0.
weight_Y
Set the frequency domain weight expression for the luma plane.
weight_U
Set the frequency domain weight expression for the 1st chroma plane.
weight_V
Set the frequency domain weight expression for the 2nd chroma plane.
eval
Set when the expressions are evaluated.
It accepts the following values:
init
Only evaluate expressions once during the filter initialization.
frame
Evaluate expressions for each incoming frame.
Default value is init.
The filter accepts the following variables:
X
Y The coordinates of the current sample.
W
H The width and height of the image.
N The number of input frame, starting from 0.
WS
HS The size of FFT array for horizontal and vertical processing.
Examples
• High-pass:
fftfilt=dc_Y=128:weight_Y='squish(1-(Y+X)/100)'
• Low-pass:
fftfilt=dc_Y=0:weight_Y='squish((Y+X)/100-1)'
• Sharpen:
fftfilt=dc_Y=0:weight_Y='1+squish(1-(Y+X)/100)'
• Blur:
fftfilt=dc_Y=0:weight_Y='exp(-4 * ((Y+X)/(W+H)))'
field
Extract a single field from an interlaced image using stride arithmetic to avoid wasting
CPU time. The output frames are marked as non-interlaced.
The filter accepts the following options:
type
Specify whether to extract the top (if the value is 0 or "top") or the bottom field
(if the value is 1 or "bottom").
fieldhint
Create new frames by copying the top and bottom fields from surrounding frames supplied as
numbers by the hint file.
hint
Set file containing hints: absolute/relative frame numbers.
There must be one line for each frame in a clip. Each line must contain two numbers
separated by the comma, optionally followed by "-" or "+". Numbers supplied on each
line of file can not be out of [N-1,N+1] where N is current frame number for
"absolute" mode or out of [-1, 1] range for "relative" mode. First number tells from
which frame to pick up top field and second number tells from which frame to pick up
bottom field.
If optionally followed by "+" output frame will be marked as interlaced, else if
followed by "-" output frame will be marked as progressive, else it will be marked
same as input frame. If optionally followed by "t" output frame will use only top
field, or in case of "b" it will use only bottom field. If line starts with "#" or
";" that line is skipped.
mode
Can be item "absolute" or "relative" or "pattern". Default is "absolute". The
"pattern" mode is same as "relative" mode, except at last entry of file if there are
more frames to process than "hint" file is seek back to start.
Example of first several lines of "hint" file for "relative" mode:
0,0 - # first frame
1,0 - # second frame, use third's frame top field and second's frame bottom field
1,0 - # third frame, use fourth's frame top field and third's frame bottom field
1,0 -
0,0 -
0,0 -
1,0 -
1,0 -
1,0 -
0,0 -
0,0 -
1,0 -
1,0 -
1,0 -
0,0 -
fieldmatch
Field matching filter for inverse telecine. It is meant to reconstruct the progressive
frames from a telecined stream. The filter does not drop duplicated frames, so to achieve
a complete inverse telecine "fieldmatch" needs to be followed by a decimation filter such
as decimate in the filtergraph.
The separation of the field matching and the decimation is notably motivated by the
possibility of inserting a de-interlacing filter fallback between the two. If the source
has mixed telecined and real interlaced content, "fieldmatch" will not be able to match
fields for the interlaced parts. But these remaining combed frames will be marked as
interlaced, and thus can be de-interlaced by a later filter such as yadif before
decimation.
In addition to the various configuration options, "fieldmatch" can take an optional second
stream, activated through the ppsrc option. If enabled, the frames reconstruction will be
based on the fields and frames from this second stream. This allows the first input to be
pre-processed in order to help the various algorithms of the filter, while keeping the
output lossless (assuming the fields are matched properly). Typically, a field-aware
denoiser, or brightness/contrast adjustments can help.
Note that this filter uses the same algorithms as TIVTC/TFM (AviSynth project) and
VIVTC/VFM (VapourSynth project). The later is a light clone of TFM from which "fieldmatch"
is based on. While the semantic and usage are very close, some behaviour and options names
can differ.
The decimate filter currently only works for constant frame rate input. If your input has
mixed telecined (30fps) and progressive content with a lower framerate like 24fps use the
following filterchain to produce the necessary cfr stream:
"dejudder,fps=30000/1001,fieldmatch,decimate".
The filter accepts the following options:
order
Specify the assumed field order of the input stream. Available values are:
auto
Auto detect parity (use FFmpeg's internal parity value).
bff Assume bottom field first.
tff Assume top field first.
Note that it is sometimes recommended not to trust the parity announced by the stream.
Default value is auto.
mode
Set the matching mode or strategy to use. pc mode is the safest in the sense that it
won't risk creating jerkiness due to duplicate frames when possible, but if there are
bad edits or blended fields it will end up outputting combed frames when a good match
might actually exist. On the other hand, pcn_ub mode is the most risky in terms of
creating jerkiness, but will almost always find a good frame if there is one. The
other values are all somewhere in between pc and pcn_ub in terms of risking jerkiness
and creating duplicate frames versus finding good matches in sections with bad edits,
orphaned fields, blended fields, etc.
More details about p/c/n/u/b are available in p/c/n/u/b meaning section.
Available values are:
pc 2-way matching (p/c)
pc_n
2-way matching, and trying 3rd match if still combed (p/c + n)
pc_u
2-way matching, and trying 3rd match (same order) if still combed (p/c + u)
pc_n_ub
2-way matching, trying 3rd match if still combed, and trying 4th/5th matches if
still combed (p/c + n + u/b)
pcn 3-way matching (p/c/n)
pcn_ub
3-way matching, and trying 4th/5th matches if all 3 of the original matches are
detected as combed (p/c/n + u/b)
The parenthesis at the end indicate the matches that would be used for that mode
assuming order=tff (and field on auto or top).
In terms of speed pc mode is by far the fastest and pcn_ub is the slowest.
Default value is pc_n.
ppsrc
Mark the main input stream as a pre-processed input, and enable the secondary input
stream as the clean source to pick the fields from. See the filter introduction for
more details. It is similar to the clip2 feature from VFM/TFM.
Default value is 0 (disabled).
field
Set the field to match from. It is recommended to set this to the same value as order
unless you experience matching failures with that setting. In certain circumstances
changing the field that is used to match from can have a large impact on matching
performance. Available values are:
auto
Automatic (same value as order).
bottom
Match from the bottom field.
top Match from the top field.
Default value is auto.
mchroma
Set whether or not chroma is included during the match comparisons. In most cases it
is recommended to leave this enabled. You should set this to 0 only if your clip has
bad chroma problems such as heavy rainbowing or other artifacts. Setting this to 0
could also be used to speed things up at the cost of some accuracy.
Default value is 1.
y0
y1 These define an exclusion band which excludes the lines between y0 and y1 from being
included in the field matching decision. An exclusion band can be used to ignore
subtitles, a logo, or other things that may interfere with the matching. y0 sets the
starting scan line and y1 sets the ending line; all lines in between y0 and y1
(including y0 and y1) will be ignored. Setting y0 and y1 to the same value will
disable the feature. y0 and y1 defaults to 0.
scthresh
Set the scene change detection threshold as a percentage of maximum change on the luma
plane. Good values are in the "[8.0, 14.0]" range. Scene change detection is only
relevant in case combmatch=sc. The range for scthresh is "[0.0, 100.0]".
Default value is 12.0.
combmatch
When combatch is not none, "fieldmatch" will take into account the combed scores of
matches when deciding what match to use as the final match. Available values are:
none
No final matching based on combed scores.
sc Combed scores are only used when a scene change is detected.
full
Use combed scores all the time.
Default is sc.
combdbg
Force "fieldmatch" to calculate the combed metrics for certain matches and print them.
This setting is known as micout in TFM/VFM vocabulary. Available values are:
none
No forced calculation.
pcn Force p/c/n calculations.
pcnub
Force p/c/n/u/b calculations.
Default value is none.
cthresh
This is the area combing threshold used for combed frame detection. This essentially
controls how "strong" or "visible" combing must be to be detected. Larger values mean
combing must be more visible and smaller values mean combing can be less visible or
strong and still be detected. Valid settings are from -1 (every pixel will be detected
as combed) to 255 (no pixel will be detected as combed). This is basically a pixel
difference value. A good range is "[8, 12]".
Default value is 9.
chroma
Sets whether or not chroma is considered in the combed frame decision. Only disable
this if your source has chroma problems (rainbowing, etc.) that are causing problems
for the combed frame detection with chroma enabled. Actually, using chroma=0 is
usually more reliable, except for the case where there is chroma only combing in the
source.
Default value is 0.
blockx
blocky
Respectively set the x-axis and y-axis size of the window used during combed frame
detection. This has to do with the size of the area in which combpel pixels are
required to be detected as combed for a frame to be declared combed. See the combpel
parameter description for more info. Possible values are any number that is a power
of 2 starting at 4 and going up to 512.
Default value is 16.
combpel
The number of combed pixels inside any of the blocky by blockx size blocks on the
frame for the frame to be detected as combed. While cthresh controls how "visible" the
combing must be, this setting controls "how much" combing there must be in any
localized area (a window defined by the blockx and blocky settings) on the frame.
Minimum value is 0 and maximum is "blocky x blockx" (at which point no frames will
ever be detected as combed). This setting is known as MI in TFM/VFM vocabulary.
Default value is 80.
p/c/n/u/b meaning
p/c/n
We assume the following telecined stream:
Top fields: 1 2 2 3 4
Bottom fields: 1 2 3 4 4
The numbers correspond to the progressive frame the fields relate to. Here, the first two
frames are progressive, the 3rd and 4th are combed, and so on.
When "fieldmatch" is configured to run a matching from bottom (field=bottom) this is how
this input stream get transformed:
Input stream:
T 1 2 2 3 4
B 1 2 3 4 4 <-- matching reference
Matches: c c n n c
Output stream:
T 1 2 3 4 4
B 1 2 3 4 4
As a result of the field matching, we can see that some frames get duplicated. To perform
a complete inverse telecine, you need to rely on a decimation filter after this operation.
See for instance the decimate filter.
The same operation now matching from top fields (field=top) looks like this:
Input stream:
T 1 2 2 3 4 <-- matching reference
B 1 2 3 4 4
Matches: c c p p c
Output stream:
T 1 2 2 3 4
B 1 2 2 3 4
In these examples, we can see what p, c and n mean; basically, they refer to the frame and
field of the opposite parity:
*<p matches the field of the opposite parity in the previous frame>
*<c matches the field of the opposite parity in the current frame>
*<n matches the field of the opposite parity in the next frame>
u/b
The u and b matching are a bit special in the sense that they match from the opposite
parity flag. In the following examples, we assume that we are currently matching the 2nd
frame (Top:2, bottom:2). According to the match, a 'x' is placed above and below each
matched fields.
With bottom matching (field=bottom):
Match: c p n b u
x x x x x
Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
x x x x x
Output frames:
2 1 2 2 2
2 2 2 1 3
With top matching (field=top):
Match: c p n b u
x x x x x
Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
x x x x x
Output frames:
2 2 2 1 2
2 1 3 2 2
Examples
Simple IVTC of a top field first telecined stream:
fieldmatch=order=tff:combmatch=none, decimate
Advanced IVTC, with fallback on yadif for still combed frames:
fieldmatch=order=tff:combmatch=full, yadif=deint=interlaced, decimate
fieldorder
Transform the field order of the input video.
It accepts the following parameters:
order
The output field order. Valid values are tff for top field first or bff for bottom
field first.
The default value is tff.
The transformation is done by shifting the picture content up or down by one line, and
filling the remaining line with appropriate picture content. This method is consistent
with most broadcast field order converters.
If the input video is not flagged as being interlaced, or it is already flagged as being
of the required output field order, then this filter does not alter the incoming video.
It is very useful when converting to or from PAL DV material, which is bottom field first.
For example:
ffmpeg -i in.vob -vf "fieldorder=bff" out.dv
fillborders
Fill borders of the input video, without changing video stream dimensions. Sometimes
video can have garbage at the four edges and you may not want to crop video input to keep
size multiple of some number.
This filter accepts the following options:
left
Number of pixels to fill from left border.
right
Number of pixels to fill from right border.
top Number of pixels to fill from top border.
bottom
Number of pixels to fill from bottom border.
mode
Set fill mode.
It accepts the following values:
smear
fill pixels using outermost pixels
mirror
fill pixels using mirroring (half sample symmetric)
fixed
fill pixels with constant value
reflect
fill pixels using reflecting (whole sample symmetric)
wrap
fill pixels using wrapping
fade
fade pixels to constant value
margins
fill pixels at top and bottom with weighted averages pixels near borders
Default is smear.
color
Set color for pixels in fixed or fade mode. Default is black.
Commands
This filter supports same commands as options. The command accepts the same syntax of the
corresponding option.
If the specified expression is not valid, it is kept at its current value.
find_rect
Find a rectangular object in the input video.
The object to search for must be specified as a gray8 image specified with the object
option.
For each possible match, a score is computed. If the score reaches the specified
threshold, the object is considered found.
If the input video contains multiple instances of the object, the filter will find only
one of them.
When an object is found, the following metadata entries are set in the matching frame:
lavfi.rect.w
width of object
lavfi.rect.h
height of object
lavfi.rect.x
x position of object
lavfi.rect.y
y position of object
lavfi.rect.score
match score of the found object
It accepts the following options:
object
Filepath of the object image, needs to be in gray8.
threshold
Detection threshold, expressed as a decimal number in the range 0-1.
A threshold value of 0.01 means only exact matches, a threshold of 0.99 means almost
everything matches.
Default value is 0.5.
mipmaps
Number of mipmaps, default is 3.
xmin, ymin, xmax, ymax
Specifies the rectangle in which to search.
discard
Discard frames where object is not detected. Default is disabled.
Examples
• Cover a rectangular object by the supplied image of a given video using ffmpeg:
ffmpeg -i file.ts -vf find_rect=newref.pgm,cover_rect=cover.jpg:mode=cover new.mkv
• Find the position of an object in each frame using ffprobe and write it to a log file:
ffprobe -f lavfi movie=test.mp4,find_rect=object=object.pgm:threshold=0.3 \
-show_entries frame=pkt_pts_time:frame_tags=lavfi.rect.x,lavfi.rect.y \
-of csv -o find_rect.csv
floodfill
Flood area with values of same pixel components with another values.
It accepts the following options:
x Set pixel x coordinate.
y Set pixel y coordinate.
s0 Set source #0 component value.
s1 Set source #1 component value.
s2 Set source #2 component value.
s3 Set source #3 component value.
d0 Set destination #0 component value.
d1 Set destination #1 component value.
d2 Set destination #2 component value.
d3 Set destination #3 component value.
format
Convert the input video to one of the specified pixel formats. Libavfilter will try to
pick one that is suitable as input to the next filter.
It accepts the following parameters:
pix_fmts
A '|'-separated list of pixel format names, such as "pix_fmts=yuv420p|monow|rgb24".
color_spaces
A '|'-separated list of color space names, such as
"color_spaces=bt709|bt470bg|bt2020nc".
color_ranges
A '|'-separated list of color range names, such as "color_spaces=tv|pc".
Examples
• Convert the input video to the yuv420p format
format=pix_fmts=yuv420p
Convert the input video to any of the formats in the list
format=pix_fmts=yuv420p|yuv444p|yuv410p
fps
Convert the video to specified constant frame rate by duplicating or dropping frames as
necessary.
It accepts the following parameters:
fps The desired output frame rate. It accepts expressions containing the following
constants:
source_fps
The input's frame rate
ntsc
NTSC frame rate of "30000/1001"
pal PAL frame rate of 25.0
film
Film frame rate of 24.0
ntsc_film
NTSC-film frame rate of "24000/1001"
The default is 25.
start_time
Assume the first PTS should be the given value, in seconds. This allows for
padding/trimming at the start of stream. By default, no assumption is made about the
first frame's expected PTS, so no padding or trimming is done. For example, this
could be set to 0 to pad the beginning with duplicates of the first frame if a video
stream starts after the audio stream or to trim any frames with a negative PTS.
round
Timestamp (PTS) rounding method.
Possible values are:
zero
round towards 0
inf round away from 0
down
round towards -infinity
up round towards +infinity
near
round to nearest
The default is "near".
eof_action
Action performed when reading the last frame.
Possible values are:
round
Use same timestamp rounding method as used for other frames.
pass
Pass through last frame if input duration has not been reached yet.
The default is "round".
Alternatively, the options can be specified as a flat string: fps[:start_time[:round]].
See also the setpts filter.
Examples
• A typical usage in order to set the fps to 25:
fps=fps=25
• Sets the fps to 24, using abbreviation and rounding method to round to nearest:
fps=fps=film:round=near
framepack
Pack two different video streams into a stereoscopic video, setting proper metadata on
supported codecs. The two views should have the same size and framerate and processing
will stop when the shorter video ends. Please note that you may conveniently adjust view
properties with the scale and fps filters.
It accepts the following parameters:
format
The desired packing format. Supported values are:
sbs The views are next to each other (default).
tab The views are on top of each other.
lines
The views are packed by line.
columns
The views are packed by column.
frameseq
The views are temporally interleaved.
Some examples:
# Convert left and right views into a frame-sequential video
ffmpeg -i LEFT -i RIGHT -filter_complex framepack=frameseq OUTPUT
# Convert views into a side-by-side video with the same output resolution as the input
ffmpeg -i LEFT -i RIGHT -filter_complex [0:v]scale=w=iw/2[left],[1:v]scale=w=iw/2[right],[left][right]framepack=sbs OUTPUT
framerate
Change the frame rate by interpolating new video output frames from the source frames.
This filter is not designed to function correctly with interlaced media. If you wish to
change the frame rate of interlaced media then you are required to deinterlace before this
filter and re-interlace after this filter.
A description of the accepted options follows.
fps Specify the output frames per second. This option can also be specified as a value
alone. The default is 50.
interp_start
Specify the start of a range where the output frame will be created as a linear
interpolation of two frames. The range is [0-255], the default is 15.
interp_end
Specify the end of a range where the output frame will be created as a linear
interpolation of two frames. The range is [0-255], the default is 240.
scene
Specify the level at which a scene change is detected as a value between 0 and 100 to
indicate a new scene; a low value reflects a low probability for the current frame to
introduce a new scene, while a higher value means the current frame is more likely to
be one. The default is 8.2.
flags
Specify flags influencing the filter process.
Available value for flags is:
scene_change_detect, scd
Enable scene change detection using the value of the option scene. This flag is
enabled by default.
framestep
Select one frame every N-th frame.
This filter accepts the following option:
step
Select frame after every "step" frames. Allowed values are positive integers higher
than 0. Default value is 1.
freezedetect
Detect frozen video.
This filter logs a message and sets frame metadata when it detects that the input video
has no significant change in content during a specified duration. Video freeze detection
calculates the mean average absolute difference of all the components of video frames and
compares it to a noise floor.
The printed times and duration are expressed in seconds. The
"lavfi.freezedetect.freeze_start" metadata key is set on the first frame whose timestamp
equals or exceeds the detection duration and it contains the timestamp of the first frame
of the freeze. The "lavfi.freezedetect.freeze_duration" and
"lavfi.freezedetect.freeze_end" metadata keys are set on the first frame after the freeze.
The filter accepts the following options:
noise, n
Set noise tolerance. Can be specified in dB (in case "dB" is appended to the specified
value) or as a difference ratio between 0 and 1. Default is -60dB, or 0.001.
duration, d
Set freeze duration until notification (default is 2 seconds).
freezeframes
Freeze video frames.
This filter freezes video frames using frame from 2nd input.
The filter accepts the following options:
first
Set number of first frame from which to start freeze.
last
Set number of last frame from which to end freeze.
replace
Set number of frame from 2nd input which will be used instead of replaced frames.
frei0r
Apply a frei0r effect to the input video.
To enable the compilation of this filter, you need to install the frei0r header and
configure FFmpeg with "--enable-frei0r".
It accepts the following parameters:
filter_name
The name of the frei0r effect to load. If the environment variable FREI0R_PATH is
defined, the frei0r effect is searched for in each of the directories specified by the
colon-separated list in FREI0R_PATH. Otherwise, the standard frei0r paths are
searched, in this order: HOME/.frei0r-1/lib/, /usr/local/lib/frei0r-1/,
/usr/lib/frei0r-1/.
filter_params
A '|'-separated list of parameters to pass to the frei0r effect.
A frei0r effect parameter can be a boolean (its value is either "y" or "n"), a double, a
color (specified as R/G/B, where R, G, and B are floating point numbers between 0.0 and
1.0, inclusive) or a color description as specified in the "Color" section in the ffmpeg-
utils manual, a position (specified as X/Y, where X and Y are floating point numbers)
and/or a string.
The number and types of parameters depend on the loaded effect. If an effect parameter is
not specified, the default value is set.
Examples
• Apply the distort0r effect, setting the first two double parameters:
frei0r=filter_name=distort0r:filter_params=0.5|0.01
• Apply the colordistance effect, taking a color as the first parameter:
frei0r=colordistance:0.2/0.3/0.4
frei0r=colordistance:violet
frei0r=colordistance:0x112233
• Apply the perspective effect, specifying the top left and top right image positions:
frei0r=perspective:0.2/0.2|0.8/0.2
For more information, see <http://frei0r.dyne.org>
Commands
This filter supports the filter_params option as commands.
fspp
Apply fast and simple postprocessing. It is a faster version of spp.
It splits (I)DCT into horizontal/vertical passes. Unlike the simple post- processing
filter, one of them is performed once per block, not per pixel. This allows for much
higher speed.
The filter accepts the following options:
quality
Set quality. This option defines the number of levels for averaging. It accepts an
integer in the range 4-5. Default value is 4.
qp Force a constant quantization parameter. It accepts an integer in range 0-63. If not
set, the filter will use the QP from the video stream (if available).
strength
Set filter strength. It accepts an integer in range -15 to 32. Lower values mean more
details but also more artifacts, while higher values make the image smoother but also
blurrier. Default value is 0 − PSNR optimal.
use_bframe_qp
Enable the use of the QP from the B-Frames if set to 1. Using this option may cause
flicker since the B-Frames have often larger QP. Default is 0 (not enabled).
fsync
Synchronize video frames with an external mapping from a file.
For each input PTS given in the map file it either drops or creates as many frames as
necessary to recreate the sequence of output frames given in the map file.
This filter is useful to recreate the output frames of a framerate conversion by the fps
filter, recorded into a map file using the ffmpeg option "-stats_mux_pre", and do further
processing to the corresponding frames e.g. quality comparison.
Each line of the map file must contain three items per input frame, the input PTS
(decimal), the output PTS (decimal) and the output TIMEBASE (decimal/decimal), seperated
by a space. This file format corresponds to the output of "-stats_mux_pre_fmt="{ptsi}
{pts} {tb}"".
The filter assumes the map file is sorted by increasing input PTS.
The filter accepts the following options:
file, f
The filename of the map file to be used.
Example:
# Convert a video to 25 fps and record a MAP_FILE file with the default format of this filter
ffmpeg -i INPUT -vf fps=fps=25 -stats_mux_pre MAP_FILE -stats_mux_pre_fmt "{ptsi} {pts} {tb}" OUTPUT
# Sort MAP_FILE by increasing input PTS
sort -n MAP_FILE
# Use INPUT, OUTPUT and the MAP_FILE from above to compare the corresponding frames in INPUT and OUTPUT via SSIM
ffmpeg -i INPUT -i OUTPUT -filter_complex '[0:v]fsync=file=MAP_FILE[ref];[1:v][ref]ssim' -f null -
gblur
Apply Gaussian blur filter.
The filter accepts the following options:
sigma
Set horizontal sigma, standard deviation of Gaussian blur. Default is 0.5.
steps
Set number of steps for Gaussian approximation. Default is 1.
planes
Set which planes to filter. By default all planes are filtered.
sigmaV
Set vertical sigma, if negative it will be same as "sigma". Default is -1.
Commands
This filter supports same commands as options. The command accepts the same syntax of the
corresponding option.
If the specified expression is not valid, it is kept at its current value.
geq
Apply generic equation to each pixel.
The filter accepts the following options:
lum_expr, lum
Set the luma expression.
cb_expr, cb
Set the chrominance blue expression.
cr_expr, cr
Set the chrominance red expression.
alpha_expr, a
Set the alpha expression.
red_expr, r
Set the red expression.
green_expr, g
Set the green expression.
blue_expr, b
Set the blue expression.
The colorspace is selected according to the specified options. If one of the lum_expr,
cb_expr, or cr_expr options is specified, the filter will automatically select a YCbCr
colorspace. If one of the red_expr, green_expr, or blue_expr options is specified, it will
select an RGB colorspace.
If one of the chrominance expression is not defined, it falls back on the other one. If no
alpha expression is specified it will evaluate to opaque value. If none of chrominance
expressions are specified, they will evaluate to the luma expression.
The expressions can use the following variables and functions:
N The sequential number of the filtered frame, starting from 0.
X
Y The coordinates of the current sample.
W
H The width and height of the image.
SW
SH Width and height scale depending on the currently filtered plane. It is the ratio
between the corresponding luma plane number of pixels and the current plane ones. E.g.
for YUV4:2:0 the values are "1,1" for the luma plane, and "0.5,0.5" for chroma planes.
T Time of the current frame, expressed in seconds.
p(x, y)
Return the value of the pixel at location (x,y) of the current plane.
lum(x, y)
Return the value of the pixel at location (x,y) of the luma plane.
cb(x, y)
Return the value of the pixel at location (x,y) of the blue-difference chroma plane.
Return 0 if there is no such plane.
cr(x, y)
Return the value of the pixel at location (x,y) of the red-difference chroma plane.
Return 0 if there is no such plane.
r(x, y)
g(x, y)
b(x, y)
Return the value of the pixel at location (x,y) of the red/green/blue component.
Return 0 if there is no such component.
alpha(x, y)
Return the value of the pixel at location (x,y) of the alpha plane. Return 0 if there
is no such plane.
psum(x,y), lumsum(x, y), cbsum(x,y), crsum(x,y), rsum(x,y), gsum(x,y), bsum(x,y),
alphasum(x,y)
Sum of sample values in the rectangle from (0,0) to (x,y), this allows obtaining sums
of samples within a rectangle. See the functions without the sum postfix.
interpolation
Set one of interpolation methods:
nearest, n
bilinear, b
Default is bilinear.
For functions, if x and y are outside the area, the value will be automatically clipped to
the closer edge.
Please note that this filter can use multiple threads in which case each slice will have
its own expression state. If you want to use only a single expression state because your
expressions depend on previous state then you should limit the number of filter threads to
1.
Examples
• Flip the image horizontally:
geq=p(W-X\,Y)
• Generate a bidimensional sine wave, with angle "PI/3" and a wavelength of 100 pixels:
geq=128 + 100*sin(2*(PI/100)*(cos(PI/3)*(X-50*T) + sin(PI/3)*Y)):128:128
• Generate a fancy enigmatic moving light:
nullsrc=s=256x256,geq=random(1)/hypot(X-cos(N*0.07)*W/2-W/2\,Y-sin(N*0.09)*H/2-H/2)^2*1000000*sin(N*0.02):128:128
• Generate a quick emboss effect:
format=gray,geq=lum_expr='(p(X,Y)+(256-p(X-4,Y-4)))/2'
• Modify RGB components depending on pixel position:
geq=r='X/W*r(X,Y)':g='(1-X/W)*g(X,Y)':b='(H-Y)/H*b(X,Y)'
• Create a radial gradient that is the same size as the input (also see the vignette
filter):
geq=lum=255*gauss((X/W-0.5)*3)*gauss((Y/H-0.5)*3)/gauss(0)/gauss(0),format=gray
gradfun
Fix the banding artifacts that are sometimes introduced into nearly flat regions by
truncation to 8-bit color depth. Interpolate the gradients that should go where the bands
are, and dither them.
It is designed for playback only. Do not use it prior to lossy compression, because
compression tends to lose the dither and bring back the bands.
It accepts the following parameters:
strength
The maximum amount by which the filter will change any one pixel. This is also the
threshold for detecting nearly flat regions. Acceptable values range from .51 to 64;
the default value is 1.2. Out-of-range values will be clipped to the valid range.
radius
The neighborhood to fit the gradient to. A larger radius makes for smoother gradients,
but also prevents the filter from modifying the pixels near detailed regions.
Acceptable values are 8-32; the default value is 16. Out-of-range values will be
clipped to the valid range.
Alternatively, the options can be specified as a flat string: strength[:radius]
Examples
• Apply the filter with a 3.5 strength and radius of 8:
gradfun=3.5:8
• Specify radius, omitting the strength (which will fall-back to the default value):
gradfun=radius=8
graphmonitor
Show various filtergraph stats.
With this filter one can debug complete filtergraph. Especially issues with links filling
with queued frames.
The filter accepts the following options:
size, s
Set video output size. Default is hd720.
opacity, o
Set video opacity. Default is 0.9. Allowed range is from 0 to 1.
mode, m
Set output mode flags.
Available values for flags are:
full
No any filtering. Default.
compact
Show only filters with queued frames.
nozero
Show only filters with non-zero stats.
noeof
Show only filters with non-eof stat.
nodisabled
Show only filters that are enabled in timeline.
flags, f
Set flags which enable which stats are shown in video.
Available values for flags are:
none
All flags turned off.
all All flags turned on.
queue
Display number of queued frames in each link.
frame_count_in
Display number of frames taken from filter.
frame_count_out
Display number of frames given out from filter.
frame_count_delta
Display delta number of frames between above two values.
pts Display current filtered frame pts.
pts_delta
Display pts delta between current and previous frame.
time
Display current filtered frame time.
time_delta
Display time delta between current and previous frame.
timebase
Display time base for filter link.
format
Display used format for filter link.
size
Display video size or number of audio channels in case of audio used by filter
link.
rate
Display video frame rate or sample rate in case of audio used by filter link.
eof Display link output status.
sample_count_in
Display number of samples taken from filter.
sample_count_out
Display number of samples given out from filter.
sample_count_delta
Display delta number of samples between above two values.
disabled
Show the timeline filter status.
rate, r
Set upper limit for video rate of output stream, Default value is 25. This guarantee
that output video frame rate will not be higher than this value.
grayworld
A color constancy filter that applies color correction based on the grayworld assumption
See:
<https://www.researchgate.net/publication/275213614_A_New_Color_Correction_Method_for_Underwater_Imaging>
The algorithm uses linear light, so input data should be linearized beforehand (and
possibly correctly tagged).
ffmpeg -i INPUT -vf zscale=transfer=linear,grayworld,zscale=transfer=bt709,format=yuv420p OUTPUT
greyedge
A color constancy variation filter which estimates scene illumination via grey edge
algorithm and corrects the scene colors accordingly.
See: <https://staff.science.uva.nl/th.gevers/pub/GeversTIP07.pdf>
The filter accepts the following options:
difford
The order of differentiation to be applied on the scene. Must be chosen in the range
[0,2] and default value is 1.
minknorm
The Minkowski parameter to be used for calculating the Minkowski distance. Must be
chosen in the range [0,20] and default value is 1. Set to 0 for getting max value
instead of calculating Minkowski distance.
sigma
The standard deviation of Gaussian blur to be applied on the scene. Must be chosen in
the range [0,1024.0] and default value = 1. floor( sigma * break_off_sigma(3) ) can't
be equal to 0 if difford is greater than 0.
Examples
• Grey Edge:
greyedge=difford=1:minknorm=5:sigma=2
• Max Edge:
greyedge=difford=1:minknorm=0:sigma=2
guided
Apply guided filter for edge-preserving smoothing, dehazing and so on.
The filter accepts the following options:
radius
Set the box radius in pixels. Allowed range is 1 to 20. Default is 3.
eps Set regularization parameter (with square). Allowed range is 0 to 1. Default is 0.01.
mode
Set filter mode. Can be "basic" or "fast". Default is "basic".
sub Set subsampling ratio for "fast" mode. Range is 2 to 64. Default is 4. No
subsampling occurs in "basic" mode.
guidance
Set guidance mode. Can be "off" or "on". Default is "off". If "off", single input is
required. If "on", two inputs of the same resolution and pixel format are required.
The second input serves as the guidance.
planes
Set planes to filter. Default is first only.
Commands
This filter supports the all above options as commands.
Examples
• Edge-preserving smoothing with guided filter:
ffmpeg -i in.png -vf guided out.png
• Dehazing, structure-transferring filtering, detail enhancement with guided filter.
For the generation of guidance image, refer to paper "Guided Image Filtering". See:
<http://kaiminghe.com/publications/pami12guidedfilter.pdf>.
ffmpeg -i in.png -i guidance.png -filter_complex guided=guidance=on out.png
haldclut
Apply a Hald CLUT to a video stream.
First input is the video stream to process, and second one is the Hald CLUT. The Hald
CLUT input can be a simple picture or a complete video stream.
The filter accepts the following options:
clut
Set which CLUT video frames will be processed from second input stream, can be first
or all. Default is all.
shortest
Force termination when the shortest input terminates. Default is 0.
repeatlast
Continue applying the last CLUT after the end of the stream. A value of 0 disable the
filter after the last frame of the CLUT is reached. Default is 1.
"haldclut" also has the same interpolation options as lut3d (both filters share the same
internals).
This filter also supports the framesync options.
More information about the Hald CLUT can be found on Eskil Steenberg's website (Hald CLUT
author) at <http://www.quelsolaar.com/technology/clut.html>.
Commands
This filter supports the "interp" option as commands.
Workflow examples
Hald CLUT video stream
Generate an identity Hald CLUT stream altered with various effects:
ffmpeg -f lavfi -i B<haldclutsrc>=8 -vf "hue=H=2*PI*t:s=sin(2*PI*t)+1, curves=cross_process" -t 10 -c:v ffv1 clut.nut
Note: make sure you use a lossless codec.
Then use it with "haldclut" to apply it on some random stream:
ffmpeg -f lavfi -i mandelbrot -i clut.nut -filter_complex '[0][1] haldclut' -t 20 mandelclut.mkv
The Hald CLUT will be applied to the 10 first seconds (duration of clut.nut), then the
latest picture of that CLUT stream will be applied to the remaining frames of the
"mandelbrot" stream.
Hald CLUT with preview
A Hald CLUT is supposed to be a squared image of "Level*Level*Level" by
"Level*Level*Level" pixels. For a given Hald CLUT, FFmpeg will select the biggest possible
square starting at the top left of the picture. The remaining padding pixels (bottom or
right) will be ignored. This area can be used to add a preview of the Hald CLUT.
Typically, the following generated Hald CLUT will be supported by the "haldclut" filter:
ffmpeg -f lavfi -i B<haldclutsrc>=8 -vf "
pad=iw+320 [padded_clut];
smptebars=s=320x256, split [a][b];
[padded_clut][a] overlay=W-320:h, curves=color_negative [main];
[main][b] overlay=W-320" -frames:v 1 clut.png
It contains the original and a preview of the effect of the CLUT: SMPTE color bars are
displayed on the right-top, and below the same color bars processed by the color changes.
Then, the effect of this Hald CLUT can be visualized with:
ffplay input.mkv -vf "movie=clut.png, [in] haldclut"
hflip
Flip the input video horizontally.
For example, to horizontally flip the input video with ffmpeg:
ffmpeg -i in.avi -vf "hflip" out.avi
histeq
This filter applies a global color histogram equalization on a per-frame basis.
It can be used to correct video that has a compressed range of pixel intensities. The
filter redistributes the pixel intensities to equalize their distribution across the
intensity range. It may be viewed as an "automatically adjusting contrast filter". This
filter is useful only for correcting degraded or poorly captured source video.
The filter accepts the following options:
strength
Determine the amount of equalization to be applied. As the strength is reduced, the
distribution of pixel intensities more-and-more approaches that of the input frame.
The value must be a float number in the range [0,1] and defaults to 0.200.
intensity
Set the maximum intensity that can generated and scale the output values
appropriately. The strength should be set as desired and then the intensity can be
limited if needed to avoid washing-out. The value must be a float number in the range
[0,1] and defaults to 0.210.
antibanding
Set the antibanding level. If enabled the filter will randomly vary the luminance of
output pixels by a small amount to avoid banding of the histogram. Possible values are
"none", "weak" or "strong". It defaults to "none".
histogram
Compute and draw a color distribution histogram for the input video.
The computed histogram is a representation of the color component distribution in an
image.
Standard histogram displays the color components distribution in an image. Displays color
graph for each color component. Shows distribution of the Y, U, V, A or R, G, B
components, depending on input format, in the current frame. Below each graph a color
component scale meter is shown.
The filter accepts the following options:
level_height
Set height of level. Default value is 200. Allowed range is [50, 2048].
scale_height
Set height of color scale. Default value is 12. Allowed range is [0, 40].
display_mode
Set display mode. It accepts the following values:
stack
Per color component graphs are placed below each other.
parade
Per color component graphs are placed side by side.
overlay
Presents information identical to that in the "parade", except that the graphs
representing color components are superimposed directly over one another.
Default is "stack".
levels_mode
Set mode. Can be either "linear", or "logarithmic". Default is "linear".
components
Set what color components to display. Default is 7.
fgopacity
Set foreground opacity. Default is 0.7.
bgopacity
Set background opacity. Default is 0.5.
colors_mode
Set colors mode. It accepts the following values:
whiteonblack
blackonwhite
whiteongray
blackongray
coloronblack
coloronwhite
colorongray
blackoncolor
whiteoncolor
grayoncolor
Default is "whiteonblack".
Examples
• Calculate and draw histogram:
ffplay -i input -vf histogram
hqdn3d
This is a high precision/quality 3d denoise filter. It aims to reduce image noise,
producing smooth images and making still images really still. It should enhance
compressibility.
It accepts the following optional parameters:
luma_spatial
A non-negative floating point number which specifies spatial luma strength. It
defaults to 4.0.
chroma_spatial
A non-negative floating point number which specifies spatial chroma strength. It
defaults to 3.0*luma_spatial/4.0.
luma_tmp
A floating point number which specifies luma temporal strength. It defaults to
6.0*luma_spatial/4.0.
chroma_tmp
A floating point number which specifies chroma temporal strength. It defaults to
luma_tmp*chroma_spatial/luma_spatial.
Commands
This filter supports same commands as options. The command accepts the same syntax of the
corresponding option.
If the specified expression is not valid, it is kept at its current value.
hwdownload
Download hardware frames to system memory.
The input must be in hardware frames, and the output a non-hardware format. Not all
formats will be supported on the output - it may be necessary to insert an additional
format filter immediately following in the graph to get the output in a supported format.
hwmap
Map hardware frames to system memory or to another device.
This filter has several different modes of operation; which one is used depends on the
input and output formats:
• Hardware frame input, normal frame output
Map the input frames to system memory and pass them to the output. If the original
hardware frame is later required (for example, after overlaying something else on part
of it), the hwmap filter can be used again in the next mode to retrieve it.
• Normal frame input, hardware frame output
If the input is actually a software-mapped hardware frame, then unmap it - that is,
return the original hardware frame.
Otherwise, a device must be provided. Create new hardware surfaces on that device for
the output, then map them back to the software format at the input and give those
frames to the preceding filter. This will then act like the hwupload filter, but may
be able to avoid an additional copy when the input is already in a compatible format.
• Hardware frame input and output
A device must be supplied for the output, either directly or with the derive_device
option. The input and output devices must be of different types and compatible - the
exact meaning of this is system-dependent, but typically it means that they must refer
to the same underlying hardware context (for example, refer to the same graphics
card).
If the input frames were originally created on the output device, then unmap to
retrieve the original frames.
Otherwise, map the frames to the output device - create new hardware frames on the
output corresponding to the frames on the input.
The following additional parameters are accepted:
mode
Set the frame mapping mode. Some combination of:
read
The mapped frame should be readable.
write
The mapped frame should be writeable.
overwrite
The mapping will always overwrite the entire frame.
This may improve performance in some cases, as the original contents of the frame
need not be loaded.
direct
The mapping must not involve any copying.
Indirect mappings to copies of frames are created in some cases where either
direct mapping is not possible or it would have unexpected properties. Setting
this flag ensures that the mapping is direct and will fail if that is not
possible.
Defaults to read+write if not specified.
derive_device type
Rather than using the device supplied at initialisation, instead derive a new device
of type type from the device the input frames exist on.
reverse
In a hardware to hardware mapping, map in reverse - create frames in the sink and map
them back to the source. This may be necessary in some cases where a mapping in one
direction is required but only the opposite direction is supported by the devices
being used.
This option is dangerous - it may break the preceding filter in undefined ways if
there are any additional constraints on that filter's output. Do not use it without
fully understanding the implications of its use.
hwupload
Upload system memory frames to hardware surfaces.
The device to upload to must be supplied when the filter is initialised. If using ffmpeg,
select the appropriate device with the -filter_hw_device option or with the derive_device
option. The input and output devices must be of different types and compatible - the
exact meaning of this is system-dependent, but typically it means that they must refer to
the same underlying hardware context (for example, refer to the same graphics card).
The following additional parameters are accepted:
derive_device type
Rather than using the device supplied at initialisation, instead derive a new device
of type type from the device the input frames exist on.
hwupload_cuda
Upload system memory frames to a CUDA device.
It accepts the following optional parameters:
device
The number of the CUDA device to use
hqx
Apply a high-quality magnification filter designed for pixel art. This filter was
originally created by Maxim Stepin.
It accepts the following option:
n Set the scaling dimension: 2 for "hq2x", 3 for "hq3x" and 4 for "hq4x". Default is 3.
hstack
Stack input videos horizontally.
All streams must be of same pixel format and of same height.
Note that this filter is faster than using overlay and pad filter to create same output.
The filter accepts the following option:
inputs
Set number of input streams. Default is 2.
shortest
If set to 1, force the output to terminate when the shortest input terminates. Default
value is 0.
hsvhold
Turns a certain HSV range into gray values.
This filter measures color difference between set HSV color in options and ones measured
in video stream. Depending on options, output colors can be changed to be gray or not.
The filter accepts the following options:
hue Set the hue value which will be used in color difference calculation. Allowed range
is from -360 to 360. Default value is 0.
sat Set the saturation value which will be used in color difference calculation. Allowed
range is from -1 to 1. Default value is 0.
val Set the value which will be used in color difference calculation. Allowed range is
from -1 to 1. Default value is 0.
similarity
Set similarity percentage with the key color. Allowed range is from 0 to 1. Default
value is 0.01.
0.00001 matches only the exact key color, while 1.0 matches everything.
blend
Blend percentage. Allowed range is from 0 to 1. Default value is 0.
0.0 makes pixels either fully gray, or not gray at all.
Higher values result in more gray pixels, with a higher gray pixel the more similar
the pixels color is to the key color.
hsvkey
Turns a certain HSV range into transparency.
This filter measures color difference between set HSV color in options and ones measured
in video stream. Depending on options, output colors can be changed to transparent by
adding alpha channel.
The filter accepts the following options:
hue Set the hue value which will be used in color difference calculation. Allowed range
is from -360 to 360. Default value is 0.
sat Set the saturation value which will be used in color difference calculation. Allowed
range is from -1 to 1. Default value is 0.
val Set the value which will be used in color difference calculation. Allowed range is
from -1 to 1. Default value is 0.
similarity
Set similarity percentage with the key color. Allowed range is from 0 to 1. Default
value is 0.01.
0.00001 matches only the exact key color, while 1.0 matches everything.
blend
Blend percentage. Allowed range is from 0 to 1. Default value is 0.
0.0 makes pixels either fully transparent, or not transparent at all.
Higher values result in semi-transparent pixels, with a higher transparency the more
similar the pixels color is to the key color.
hue
Modify the hue and/or the saturation of the input.
It accepts the following parameters:
h Specify the hue angle as a number of degrees. It accepts an expression, and defaults
to "0".
s Specify the saturation in the [-10,10] range. It accepts an expression and defaults to
"1".
H Specify the hue angle as a number of radians. It accepts an expression, and defaults
to "0".
b Specify the brightness in the [-10,10] range. It accepts an expression and defaults to
"0".
h and H are mutually exclusive, and can't be specified at the same time.
The b, h, H and s option values are expressions containing the following constants:
n frame count of the input frame starting from 0
pts presentation timestamp of the input frame expressed in time base units
r frame rate of the input video, NAN if the input frame rate is unknown
t timestamp expressed in seconds, NAN if the input timestamp is unknown
tb time base of the input video
Examples
• Set the hue to 90 degrees and the saturation to 1.0:
hue=h=90:s=1
• Same command but expressing the hue in radians:
hue=H=PI/2:s=1
• Rotate hue and make the saturation swing between 0 and 2 over a period of 1 second:
hue="H=2*PI*t: s=sin(2*PI*t)+1"
• Apply a 3 seconds saturation fade-in effect starting at 0:
hue="s=min(t/3\,1)"
The general fade-in expression can be written as:
hue="s=min(0\, max((t-START)/DURATION\, 1))"
• Apply a 3 seconds saturation fade-out effect starting at 5 seconds:
hue="s=max(0\, min(1\, (8-t)/3))"
The general fade-out expression can be written as:
hue="s=max(0\, min(1\, (START+DURATION-t)/DURATION))"
Commands
This filter supports the following commands:
b
s
h
H Modify the hue and/or the saturation and/or brightness of the input video. The
command accepts the same syntax of the corresponding option.
If the specified expression is not valid, it is kept at its current value.
huesaturation
Apply hue-saturation-intensity adjustments to input video stream.
This filter operates in RGB colorspace.
This filter accepts the following options:
hue Set the hue shift in degrees to apply. Default is 0. Allowed range is from -180 to
180.
saturation
Set the saturation shift. Default is 0. Allowed range is from -1 to 1.
intensity
Set the intensity shift. Default is 0. Allowed range is from -1 to 1.
colors
Set which primary and complementary colors are going to be adjusted. This options is
set by providing one or multiple values. This can select multiple colors at once. By
default all colors are selected.
r Adjust reds.
y Adjust yellows.
g Adjust greens.
c Adjust cyans.
b Adjust blues.
m Adjust magentas.
a Adjust all colors.
strength
Set strength of filtering. Allowed range is from 0 to 100. Default value is 1.
rw, gw, bw
Set weight for each RGB component. Allowed range is from 0 to 1. By default is set to
0.333, 0.334, 0.333. Those options are used in saturation and lightess processing.
lightness
Set preserving lightness, by default is disabled. Adjusting hues can change lightness
from original RGB triplet, with this option enabled lightness is kept at same value.
hysteresis
Grow first stream into second stream by connecting components. This makes it possible to
build more robust edge masks.
This filter accepts the following options:
planes
Set which planes will be processed as bitmap, unprocessed planes will be copied from
first stream. By default value 0xf, all planes will be processed.
threshold
Set threshold which is used in filtering. If pixel component value is higher than this
value filter algorithm for connecting components is activated. By default value is 0.
The "hysteresis" filter also supports the framesync options.
iccdetect
Detect the colorspace from an embedded ICC profile (if present), and update the frame's
tags accordingly.
This filter accepts the following options:
force
If true, the frame's existing colorspace tags will always be overridden by values
detected from an ICC profile. Otherwise, they will only be assigned if they contain
"unknown". Enabled by default.
iccgen
Generate ICC profiles and attach them to frames.
This filter accepts the following options:
color_primaries
color_trc
Configure the colorspace that the ICC profile will be generated for. The default value
of "auto" infers the value from the input frame's metadata, defaulting to BT.709/sRGB
as appropriate.
See the setparams filter for a list of possible values, but note that "unknown" are
not valid values for this filter.
force
If true, an ICC profile will be generated even if it would overwrite an already
existing ICC profile. Disabled by default.
identity
Obtain the identity score between two input videos.
This filter takes two input videos.
Both input videos must have the same resolution and pixel format for this filter to work
correctly. Also it assumes that both inputs have the same number of frames, which are
compared one by one.
The obtained per component, average, min and max identity score is printed through the
logging system.
The filter stores the calculated identity scores of each frame in frame metadata.
This filter also supports the framesync options.
In the below example the input file main.mpg being processed is compared with the
reference file ref.mpg.
ffmpeg -i main.mpg -i ref.mpg -lavfi identity -f null -
idet
Detect video interlacing type.
This filter tries to detect if the input frames are interlaced, progressive, top or bottom
field first. It will also try to detect fields that are repeated between adjacent frames
(a sign of telecine).
Single frame detection considers only immediately adjacent frames when classifying each
frame. Multiple frame detection incorporates the classification history of previous
frames.
The filter will log these metadata values:
single.current_frame
Detected type of current frame using single-frame detection. One of: ``tff'' (top
field first), ``bff'' (bottom field first), ``progressive'', or ``undetermined''
single.tff
Cumulative number of frames detected as top field first using single-frame detection.
multiple.tff
Cumulative number of frames detected as top field first using multiple-frame
detection.
single.bff
Cumulative number of frames detected as bottom field first using single-frame
detection.
multiple.current_frame
Detected type of current frame using multiple-frame detection. One of: ``tff'' (top
field first), ``bff'' (bottom field first), ``progressive'', or ``undetermined''
multiple.bff
Cumulative number of frames detected as bottom field first using multiple-frame
detection.
single.progressive
Cumulative number of frames detected as progressive using single-frame detection.
multiple.progressive
Cumulative number of frames detected as progressive using multiple-frame detection.
single.undetermined
Cumulative number of frames that could not be classified using single-frame detection.
multiple.undetermined
Cumulative number of frames that could not be classified using multiple-frame
detection.
repeated.current_frame
Which field in the current frame is repeated from the last. One of ``neither'',
``top'', or ``bottom''.
repeated.neither
Cumulative number of frames with no repeated field.
repeated.top
Cumulative number of frames with the top field repeated from the previous frame's top
field.
repeated.bottom
Cumulative number of frames with the bottom field repeated from the previous frame's
bottom field.
The filter accepts the following options:
intl_thres
Set interlacing threshold.
prog_thres
Set progressive threshold.
rep_thres
Threshold for repeated field detection.
half_life
Number of frames after which a given frame's contribution to the statistics is halved
(i.e., it contributes only 0.5 to its classification). The default of 0 means that all
frames seen are given full weight of 1.0 forever.
analyze_interlaced_flag
When this is not 0 then idet will use the specified number of frames to determine if
the interlaced flag is accurate, it will not count undetermined frames. If the flag
is found to be accurate it will be used without any further computations, if it is
found to be inaccurate it will be cleared without any further computations. This
allows inserting the idet filter as a low computational method to clean up the
interlaced flag
Examples
Inspect the field order of the first 360 frames in a video, in verbose detail:
ffmpeg -i INPUT -filter:v idet,metadata=mode=print -frames:v 360 -an -f null -
The idet filter will add analysis metadata to each frame, which will then be discarded. At
the end, the filter will also print a final report with statistics.
il
Deinterleave or interleave fields.
This filter allows one to process interlaced images fields without deinterlacing them.
Deinterleaving splits the input frame into 2 fields (so called half pictures). Odd lines
are moved to the top half of the output image, even lines to the bottom half. You can
process (filter) them independently and then re-interleave them.
The filter accepts the following options:
luma_mode, l
chroma_mode, c
alpha_mode, a
Available values for luma_mode, chroma_mode and alpha_mode are:
none
Do nothing.
deinterleave, d
Deinterleave fields, placing one above the other.
interleave, i
Interleave fields. Reverse the effect of deinterleaving.
Default value is "none".
luma_swap, ls
chroma_swap, cs
alpha_swap, as
Swap luma/chroma/alpha fields. Exchange even & odd lines. Default value is 0.
Commands
This filter supports the all above options as commands.
inflate
Apply inflate effect to the video.
This filter replaces the pixel by the local(3x3) average by taking into account only
values higher than the pixel.
It accepts the following options:
threshold0
threshold1
threshold2
threshold3
Limit the maximum change for each plane, default is 65535. If 0, plane will remain
unchanged.
Commands
This filter supports the all above options as commands.
interlace
Simple interlacing filter from progressive contents. This interleaves upper (or lower)
lines from odd frames with lower (or upper) lines from even frames, halving the frame rate
and preserving image height.
Original Original New Frame
Frame 'j' Frame 'j+1' (tff)
========== =========== ==================
Line 0 --------------------> Frame 'j' Line 0
Line 1 Line 1 ----> Frame 'j+1' Line 1
Line 2 ---------------------> Frame 'j' Line 2
Line 3 Line 3 ----> Frame 'j+1' Line 3
... ... ...
New Frame + 1 will be generated by Frame 'j+2' and Frame 'j+3' and so on
It accepts the following optional parameters:
scan
This determines whether the interlaced frame is taken from the even (tff - default) or
odd (bff) lines of the progressive frame.
lowpass
Vertical lowpass filter to avoid twitter interlacing and reduce moire patterns.
0, off
Disable vertical lowpass filter
1, linear
Enable linear filter (default)
2, complex
Enable complex filter. This will slightly less reduce twitter and moire but better
retain detail and subjective sharpness impression.
kerndeint
Deinterlace input video by applying Donald Graft's adaptive kernel deinterling. Work on
interlaced parts of a video to produce progressive frames.
The description of the accepted parameters follows.
thresh
Set the threshold which affects the filter's tolerance when determining if a pixel
line must be processed. It must be an integer in the range [0,255] and defaults to 10.
A value of 0 will result in applying the process on every pixels.
map Paint pixels exceeding the threshold value to white if set to 1. Default is 0.
order
Set the fields order. Swap fields if set to 1, leave fields alone if 0. Default is 0.
sharp
Enable additional sharpening if set to 1. Default is 0.
twoway
Enable twoway sharpening if set to 1. Default is 0.
Examples
• Apply default values:
kerndeint=thresh=10:map=0:order=0:sharp=0:twoway=0
• Enable additional sharpening:
kerndeint=sharp=1
• Paint processed pixels in white:
kerndeint=map=1
kirsch
Apply kirsch operator to input video stream.
The filter accepts the following option:
planes
Set which planes will be processed, unprocessed planes will be copied. By default
value 0xf, all planes will be processed.
scale
Set value which will be multiplied with filtered result.
delta
Set value which will be added to filtered result.
Commands
This filter supports the all above options as commands.
lagfun
Slowly update darker pixels.
This filter makes short flashes of light appear longer. This filter accepts the following
options:
decay
Set factor for decaying. Default is .95. Allowed range is from 0 to 1.
planes
Set which planes to filter. Default is all. Allowed range is from 0 to 15.
Commands
This filter supports the all above options as commands.
lenscorrection
Correct radial lens distortion
This filter can be used to correct for radial distortion as can result from the use of
wide angle lenses, and thereby re-rectify the image. To find the right parameters one can
use tools available for example as part of opencv or simply trial-and-error. To use
opencv use the calibration sample (under samples/cpp) from the opencv sources and extract
the k1 and k2 coefficients from the resulting matrix.
Note that effectively the same filter is available in the open-source tools Krita and
Digikam from the KDE project.
In contrast to the vignette filter, which can also be used to compensate lens errors, this
filter corrects the distortion of the image, whereas vignette corrects the brightness
distribution, so you may want to use both filters together in certain cases, though you
will have to take care of ordering, i.e. whether vignetting should be applied before or
after lens correction.
Options
The filter accepts the following options:
cx Relative x-coordinate of the focal point of the image, and thereby the center of the
distortion. This value has a range [0,1] and is expressed as fractions of the image
width. Default is 0.5.
cy Relative y-coordinate of the focal point of the image, and thereby the center of the
distortion. This value has a range [0,1] and is expressed as fractions of the image
height. Default is 0.5.
k1 Coefficient of the quadratic correction term. This value has a range [-1,1]. 0 means
no correction. Default is 0.
k2 Coefficient of the double quadratic correction term. This value has a range [-1,1]. 0
means no correction. Default is 0.
i Set interpolation type. Can be "nearest" or "bilinear". Default is "nearest".
fc Specify the color of the unmapped pixels. For the syntax of this option, check the
"Color" section in the ffmpeg-utils manual. Default color is "black@0".
The formula that generates the correction is:
r_src = r_tgt * (1 + k1 * (r_tgt / r_0)^2 + k2 * (r_tgt / r_0)^4)
where r_0 is halve of the image diagonal and r_src and r_tgt are the distances from the
focal point in the source and target images, respectively.
Commands
This filter supports the all above options as commands.
lensfun
Apply lens correction via the lensfun library (<http://lensfun.sourceforge.net/>).
The "lensfun" filter requires the camera make, camera model, and lens model to apply the
lens correction. The filter will load the lensfun database and query it to find the
corresponding camera and lens entries in the database. As long as these entries can be
found with the given options, the filter can perform corrections on frames. Note that
incomplete strings will result in the filter choosing the best match with the given
options, and the filter will output the chosen camera and lens models (logged with level
"info"). You must provide the make, camera model, and lens model as they are required.
To obtain a list of available makes and models, leave out one or both of "make" and
"model" options. The filter will send the full list to the log with level "INFO". The
first column is the make and the second column is the model. To obtain a list of
available lenses, set any values for make and model and leave out the "lens_model" option.
The filter will send the full list of lenses in the log with level "INFO". The ffmpeg tool
will exit after the list is printed.
The filter accepts the following options:
make
The make of the camera (for example, "Canon"). This option is required.
model
The model of the camera (for example, "Canon EOS 100D"). This option is required.
lens_model
The model of the lens (for example, "Canon EF-S 18-55mm f/3.5-5.6 IS STM"). This
option is required.
db_path
The full path to the lens database folder. If not set, the filter will attempt to load
the database from the install path when the library was built. Default is unset.
mode
The type of correction to apply. The following values are valid options:
vignetting
Enables fixing lens vignetting.
geometry
Enables fixing lens geometry. This is the default.
subpixel
Enables fixing chromatic aberrations.
vig_geo
Enables fixing lens vignetting and lens geometry.
vig_subpixel
Enables fixing lens vignetting and chromatic aberrations.
distortion
Enables fixing both lens geometry and chromatic aberrations.
all Enables all possible corrections.
focal_length
The focal length of the image/video (zoom; expected constant for video). For example,
a 18--55mm lens has focal length range of [18--55], so a value in that range should be
chosen when using that lens. Default 18.
aperture
The aperture of the image/video (expected constant for video). Note that aperture is
only used for vignetting correction. Default 3.5.
focus_distance
The focus distance of the image/video (expected constant for video). Note that focus
distance is only used for vignetting and only slightly affects the vignetting
correction process. If unknown, leave it at the default value (which is 1000).
scale
The scale factor which is applied after transformation. After correction the video is
no longer necessarily rectangular. This parameter controls how much of the resulting
image is visible. The value 0 means that a value will be chosen automatically such
that there is little or no unmapped area in the output image. 1.0 means that no
additional scaling is done. Lower values may result in more of the corrected image
being visible, while higher values may avoid unmapped areas in the output.
target_geometry
The target geometry of the output image/video. The following values are valid options:
rectilinear (default)
fisheye
panoramic
equirectangular
fisheye_orthographic
fisheye_stereographic
fisheye_equisolid
fisheye_thoby
reverse
Apply the reverse of image correction (instead of correcting distortion, apply it).
interpolation
The type of interpolation used when correcting distortion. The following values are
valid options:
nearest
linear (default)
lanczos
Examples
• Apply lens correction with make "Canon", camera model "Canon EOS 100D", and lens model
"Canon EF-S 18-55mm f/3.5-5.6 IS STM" with focal length of "18" and aperture of "8.0".
ffmpeg -i input.mov -vf lensfun=make=Canon:model="Canon EOS 100D":lens_model="Canon EF-S 18-55mm f/3.5-5.6 IS STM":focal_length=18:aperture=8 -c:v h264 -b:v 8000k output.mov
• Apply the same as before, but only for the first 5 seconds of video.
ffmpeg -i input.mov -vf lensfun=make=Canon:model="Canon EOS 100D":lens_model="Canon EF-S 18-55mm f/3.5-5.6 IS STM":focal_length=18:aperture=8:enable='lte(t\,5)' -c:v h264 -b:v 8000k output.mov
libplacebo
Flexible GPU-accelerated processing filter based on libplacebo
(<https://code.videolan.org/videolan/libplacebo>).
Options
The options for this filter are divided into the following sections:
Output mode
These options control the overall output mode. By default, libplacebo will try to preserve
the source colorimetry and size as best as it can, but it will apply any embedded film
grain, dolby vision metadata or anamorphic SAR present in source frames.
inputs
Set the number of inputs. This can be used, alongside the "idx" variable, to allow
placing/blending multiple inputs inside the output frame. This effectively enables
functionality similar to hstack, overlay, etc.
w
h Set the output video dimension expression. Default values are "iw" and "ih".
Allows for the same expressions as the scale filter.
crop_x
crop_y
Set the input crop x/y expressions, default values are "(iw-cw)/2" and "(ih-ch)/2".
crop_w
crop_h
Set the input crop width/height expressions, default values are "iw" and "ih".
pos_x
pos_y
Set the output placement x/y expressions, default values are "(ow-pw)/2" and
"(oh-ph)/2".
pos_w
pos_h
Set the output placement width/height expressions, default values are "ow" and "oh".
fps Set the output frame rate. This can be rational, e.g. "60000/1001". If set to the
special string "none" (the default), input timestamps will instead be passed through
to the output unmodified. Otherwise, the input video frames will be interpolated as
necessary to rescale the video to the specified target framerate, in a manner as
determined by the frame_mixer option.
format
Set the output format override. If unset (the default), frames will be output in the
same format as the respective input frames. Otherwise, format conversion will be
performed.
force_original_aspect_ratio
force_divisible_by
Work the same as the identical scale filter options.
normalize_sar
If enabled, output frames will always have a pixel aspect ratio of 1:1. This will
introduce additional padding/cropping as necessary. If disabled (the default), any
aspect ratio mismatches, including those from e.g. anamorphic video sources, are
forwarded to the output pixel aspect ratio.
pad_crop_ratio
Specifies a ratio (between 0.0 and 1.0) between padding and cropping when the input
aspect ratio does not match the output aspect ratio and normalize_sar is in effect.
The default of 0.0 always pads the content with black borders, while a value of 1.0
always crops off parts of the content. Intermediate values are possible, leading to a
mix of the two approaches.
fillcolor
Set the color used to fill the output area not covered by the output image, for
example as a result of normalize_sar. For the general syntax of this option, check the
"Color" section in the ffmpeg-utils manual. Defaults to "black".
corner_rounding
Render frames with rounded corners. The value, given as a float ranging from 0.0 to
1.0, indicates the relative degree of rounding, from fully square to fully circular.
In other words, it gives the radius divided by half the smaller side length. Defaults
to 0.0.
extra_opts
Pass extra libplacebo internal configuration options. These can be specified as a list
of key=value pairs separated by ':'. The following example shows how to configure a
custom filter kernel ("EWA LanczosSharp") and use it to double the input image
resolution:
-vf "libplacebo=w=iw*2:h=ih*2:extra_opts='upscaler=custom\:upscaler_preset=ewa_lanczos\:upscaler_blur=0.9812505644269356'"
colorspace
color_primaries
color_trc
range
Configure the colorspace that output frames will be delivered in. The default value of
"auto" outputs frames in the same format as the input frames, leading to no change.
For any other value, conversion will be performed.
See the setparams filter for a list of possible values.
apply_filmgrain
Apply film grain (e.g. AV1 or H.274) if present in source frames, and strip it from
the output. Enabled by default.
apply_dolbyvision
Apply Dolby Vision RPU metadata if present in source frames, and strip it from the
output. Enabled by default. Note that Dolby Vision will always output BT.2020+PQ,
overriding the usual input frame metadata. These will also be picked as the values of
"auto" for the respective frame output options.
In addition to the expression constants documented for the scale filter, the crop_w,
crop_h, crop_x, crop_y, pos_w, pos_h, pos_x and pos_y options can also contain the
following constants:
in_idx, idx
The (0-based) numeric index of the currently active input stream.
crop_w, cw
crop_h, ch
The computed values of crop_w and crop_h.
pos_w, pw
pos_h, ph
The computed values of pos_w and pos_h.
in_t, t
The input frame timestamp, in seconds. NAN if input timestamp is unknown.
out_t, ot
The input frame timestamp, in seconds. NAN if input timestamp is unknown.
n The input frame number, starting with 0.
Scaling
The options in this section control how libplacebo performs upscaling and (if necessary)
downscaling. Note that libplacebo will always internally operate on 4:4:4 content, so any
sub-sampled chroma formats such as "yuv420p" will necessarily be upsampled and downsampled
as part of the rendering process. That means scaling might be in effect even if the source
and destination resolution are the same.
upscaler
downscaler
Configure the filter kernel used for upscaling and downscaling. The respective
defaults are "spline36" and "mitchell". For a full list of possible values, pass
"help" to these options. The most important values are:
none
Forces the use of built-in GPU texture sampling (typically bilinear). Extremely
fast but poor quality, especially when downscaling.
bilinear
Bilinear interpolation. Can generally be done for free on GPUs, except when doing
so would lead to aliasing. Fast and low quality.
nearest
Nearest-neighbour interpolation. Sharp but highly aliasing.
oversample
Algorithm that looks visually similar to nearest-neighbour interpolation but tries
to preserve pixel aspect ratio. Good for pixel art, since it results in minimal
distortion of the artistic appearance.
lanczos
Standard sinc-sinc interpolation kernel.
spline36
Cubic spline approximation of lanczos. No difference in performance, but has very
slightly less ringing.
ewa_lanczos
Elliptically weighted average version of lanczos, based on a jinc-sinc kernel.
This is also popularly referred to as just "Jinc scaling". Slow but very high
quality.
gaussian
Gaussian kernel. Has certain ideal mathematical properties, but subjectively very
blurry.
mitchell
Cubic BC spline with parameters recommended by Mitchell and Netravali. Very little
ringing.
frame_mixer
Controls the kernel used for mixing frames temporally. The default value is "none",
which disables frame mixing. For a full list of possible values, pass "help" to this
option. The most important values are:
none
Disables frame mixing, giving a result equivalent to "nearest neighbour"
semantics.
oversample
Oversamples the input video to create a "Smooth Motion"-type effect: if an output
frame would exactly fall on the transition between two video frames, it is blended
according to the relative overlap. This is the recommended option whenever
preserving the original subjective appearance is desired.
mitchell_clamp
Larger filter kernel that smoothly interpolates multiple frames in a manner
designed to eliminate ringing and other artefacts as much as possible. This is the
recommended option wherever maximum visual smoothness is desired.
linear
Linear blend/fade between frames. Especially useful for constructing e.g.
slideshows.
lut_entries
Configures the size of scaler LUTs, ranging from 1 to 256. The default of 0 will pick
libplacebo's internal default, typically 64.
antiringing
Enables anti-ringing (for non-EWA filters). The value (between 0.0 and 1.0) configures
the strength of the anti-ringing algorithm. May increase aliasing if set too high.
Disabled by default.
sigmoid
Enable sigmoidal compression during upscaling. Reduces ringing slightly. Enabled by
default.
Debanding
Libplacebo comes with a built-in debanding filter that is good at counteracting many
common sources of banding and blocking. Turning this on is highly recommended whenever
quality is desired.
deband
Enable (fast) debanding algorithm. Disabled by default.
deband_iterations
Number of deband iterations of the debanding algorithm. Each iteration is performed
with progressively increased radius (and diminished threshold). Recommended values
are in the range 1 to 4. Defaults to 1.
deband_threshold
Debanding filter strength. Higher numbers lead to more aggressive debanding. Defaults
to 4.0.
deband_radius
Debanding filter radius. A higher radius is better for slow gradients, while a lower
radius is better for steep gradients. Defaults to 16.0.
deband_grain
Amount of extra output grain to add. Helps hide imperfections. Defaults to 6.0.
Color adjustment
A collection of subjective color controls. Not very rigorous, so the exact effect will
vary somewhat depending on the input primaries and colorspace.
brightness
Brightness boost, between -1.0 and 1.0. Defaults to 0.0.
contrast
Contrast gain, between 0.0 and 16.0. Defaults to 1.0.
saturation
Saturation gain, between 0.0 and 16.0. Defaults to 1.0.
hue Hue shift in radians, between -3.14 and 3.14. Defaults to 0.0. This will rotate the UV
subvector, defaulting to BT.709 coefficients for RGB inputs.
gamma
Gamma adjustment, between 0.0 and 16.0. Defaults to 1.0.
cones
Cone model to use for color blindness simulation. Accepts any combination of "l", "m"
and "s". Here are some examples:
m Deuteranomaly / deuteranopia (affecting 3%-4% of the population)
l Protanomaly / protanopia (affecting 1%-2% of the population)
l+m Monochromacy (very rare)
l+m+s
Achromatopsy (complete loss of daytime vision, extremely rare)
cone-strength
Gain factor for the cones specified by "cones", between 0.0 and 10.0. A value of 1.0
results in no change to color vision. A value of 0.0 (the default) simulates complete
loss of those cones. Values above 1.0 result in exaggerating the differences between
cones, which may help compensate for reduced color vision.
Peak detection
To help deal with sources that only have static HDR10 metadata (or no tagging whatsoever),
libplacebo uses its own internal frame analysis compute shader to analyze source frames
and adapt the tone mapping function in realtime. If this is too slow, or if exactly
reproducible frame-perfect results are needed, it's recommended to turn this feature off.
peak_detect
Enable HDR peak detection. Ignores static MaxCLL/MaxFALL values in favor of dynamic
detection from the input. Note that the detected values do not get written back to the
output frames, they merely guide the internal tone mapping process. Enabled by
default.
smoothing_period
Peak detection smoothing period, between 0.0 and 1000.0. Higher values result in peak
detection becoming less responsive to changes in the input. Defaults to 100.0.
minimum_peak
Lower bound on the detected peak (relative to SDR white), between 0.0 and 100.0.
Defaults to 1.0.
scene_threshold_low
scene_threshold_high
Lower and upper thresholds for scene change detection. Expressed in a logarithmic
scale between 0.0 and 100.0. Default to 5.5 and 10.0, respectively. Setting either to
a negative value disables this functionality.
percentile
Which percentile of the frame brightness histogram to use as the source peak for tone-
mapping. Defaults to 99.995, a fairly conservative value. Setting this to 100.0
disables frame histogram measurement and instead uses the true peak brightness for
tone-mapping.
Tone mapping
The options in this section control how libplacebo performs tone-mapping and gamut-mapping
when dealing with mismatches between wide-gamut or HDR content. In general, libplacebo
relies on accurate source tagging and mastering display gamut information to produce the
best results.
gamut_mode
How to handle out-of-gamut colors that can occur as a result of colorimetric gamut
mapping.
clip
Do nothing, simply clip out-of-range colors to the RGB volume. Low quality but
extremely fast.
perceptual
Perceptually soft-clip colors to the gamut volume. This is the default.
relative
Relative colorimetric hard-clip. Similar to "perceptual" but without the soft
knee.
saturation
Saturation mapping, maps primaries directly to primaries in RGB space. Not
recommended except for artificial computer graphics for which a bright, saturated
display is desired.
absolute
Absolute colorimetric hard-clip. Performs no adjustment of the white point.
desaturate
Hard-desaturates out-of-gamut colors towards white, while preserving the
luminance. Has a tendency to distort the visual appearance of bright objects.
darken
Linearly reduces content brightness to preserves saturated details, followed by
clipping the remaining out-of-gamut colors.
warn
Highlight out-of-gamut pixels (by inverting/marking them).
linear
Linearly reduces chromaticity of the entire image to make it fit within the target
color volume. Be careful when using this on BT.2020 sources without proper
mastering metadata, as doing so will lead to excessive desaturation.
tonemapping
Tone-mapping algorithm to use. Available values are:
auto
Automatic selection based on internal heuristics. This is the default.
clip
Performs no tone-mapping, just clips out-of-range colors. Retains perfect color
accuracy for in-range colors but completely destroys out-of-range information.
Does not perform any black point adaptation. Not configurable.
st2094-40
EETF from SMPTE ST 2094-40 Annex B, which applies the Bezier curves from HDR10+
dynamic metadata based on Bezier curves to perform tone-mapping. The OOTF used is
adjusted based on the ratio between the targeted and actual display peak
luminances.
st2094-10
EETF from SMPTE ST 2094-10 Annex B.2, which takes into account the input signal
average luminance in addition to the maximum/minimum. The configurable contrast
parameter influences the slope of the linear output segment, defaulting to 1.0 for
no increase/decrease in contrast. Note that this does not currently include the
subjective gain/offset/gamma controls defined in Annex B.3.
bt.2390
EETF from the ITU-R Report BT.2390, a hermite spline roll-off with linear segment.
The knee point offset is configurable. Note that this parameter defaults to 1.0,
rather than the value of 0.5 from the ITU-R spec.
bt.2446a
EETF from ITU-R Report BT.2446, method A. Designed for well-mastered HDR sources.
Can be used for both forward and inverse tone mapping. Not configurable.
spline
Simple spline consisting of two polynomials, joined by a single pivot point. The
parameter gives the pivot point (in PQ space), defaulting to 0.30. Can be used
for both forward and inverse tone mapping.
reinhard
Simple non-linear, global tone mapping algorithm. The parameter specifies the
local contrast coefficient at the display peak. Essentially, a parameter of 0.5
implies that the reference white will be about half as bright as when clipping.
Defaults to 0.5, which results in the simplest formulation of this function.
mobius
Generalization of the reinhard tone mapping algorithm to support an additional
linear slope near black. The tone mapping parameter indicates the trade-off
between the linear section and the non-linear section. Essentially, for a given
parameter x, every color value below x will be mapped linearly, while higher
values get non-linearly tone-mapped. Values near 1.0 make this curve behave like
"clip", while values near 0.0 make this curve behave like "reinhard". The default
value is 0.3, which provides a good balance between colorimetric accuracy and
preserving out-of-gamut details.
hable
Piece-wise, filmic tone-mapping algorithm developed by John Hable for use in
Uncharted 2, inspired by a similar tone-mapping algorithm used by Kodak.
Popularized by its use in video games with HDR rendering. Preserves both dark and
bright details very well, but comes with the drawback of changing the average
brightness quite significantly. This is sort of similar to "reinhard" with
parameter 0.24.
gamma
Fits a gamma (power) function to transfer between the source and target color
spaces, effectively resulting in a perceptual hard-knee joining two roughly linear
sections. This preserves details at all scales fairly accurately, but can result
in an image with a muted or dull appearance. The parameter is used as the cutoff
point, defaulting to 0.5.
linear
Linearly stretches the input range to the output range, in PQ space. This will
preserve all details accurately, but results in a significantly different average
brightness. Can be used for inverse tone-mapping in addition to regular tone-
mapping. The parameter can be used as an additional linear gain coefficient
(defaulting to 1.0).
tonemapping_param
For tunable tone mapping functions, this parameter can be used to fine-tune the curve
behavior. Refer to the documentation of "tonemapping". The default value of 0.0 is
replaced by the curve's preferred default setting.
inverse_tonemapping
If enabled, this filter will also attempt stretching SDR signals to fill HDR output
color volumes. Disabled by default.
tonemapping_lut_size
Size of the tone-mapping LUT, between 2 and 1024. Defaults to 256. Note that this
figure is squared when combined with "peak_detect".
contrast_recovery
Contrast recovery strength. If set to a value above 0.0, the source image will be
divided into high-frequency and low-frequency components, and a portion of the high-
frequency image is added back onto the tone-mapped output. May cause excessive
ringing artifacts for some HDR sources, but can improve the subjective sharpness and
detail left over in the image after tone-mapping. Defaults to 0.30.
contrast_smoothness
Contrast recovery lowpass kernel size. Defaults to 3.5. Increasing or decreasing this
will affect the visual appearance substantially. Has no effect when
"contrast_recovery" is disabled.
Dithering
By default, libplacebo will dither whenever necessary, which includes rendering to any
integer format below 16-bit precision. It's recommended to always leave this on, since not
doing so may result in visible banding in the output, even if the "debanding" filter is
enabled. If maximum performance is needed, use "ordered_fixed" instead of disabling
dithering.
dithering
Dithering method to use. Accepts the following values:
none
Disables dithering completely. May result in visible banding.
blue
Dither with pseudo-blue noise. This is the default.
ordered
Tunable ordered dither pattern.
ordered_fixed
Faster ordered dither with a fixed size of 6. Texture-less.
white
Dither with white noise. Texture-less.
dither_lut_size
Dither LUT size, as log base2 between 1 and 8. Defaults to 6, corresponding to a LUT
size of "64x64".
dither_temporal
Enables temporal dithering. Disabled by default.
Custom shaders
libplacebo supports a number of custom shaders based on the mpv .hook GLSL syntax. A
collection of such shaders can be found here:
<https://github.com/mpv-player/mpv/wiki/User-Scripts#user-shaders>
A full description of the mpv shader format is beyond the scope of this section, but a
summary can be found here: <https://mpv.io/manual/master/#options-glsl-shader>
custom_shader_path
Specifies a path to a custom shader file to load at runtime.
custom_shader_bin
Specifies a complete custom shader as a raw string.
Debugging / performance
All of the options in this section default off. They may be of assistance when attempting
to squeeze the maximum performance at the cost of quality.
skip_aa
Disable anti-aliasing when downscaling.
polar_cutoff
Truncate polar (EWA) scaler kernels below this absolute magnitude, between 0.0 and
1.0.
disable_linear
Disable linear light scaling.
disable_builtin
Disable built-in GPU sampling (forces LUT).
disable_fbos
Forcibly disable FBOs, resulting in loss of almost all functionality, but offering the
maximum possible speed.
Commands
This filter supports almost all of the above options as commands.
Examples
• Tone-map input to standard gamut BT.709 output:
libplacebo=colorspace=bt709:color_primaries=bt709:color_trc=bt709:range=tv
• Rescale input to fit into standard 1080p, with high quality scaling:
libplacebo=w=1920:h=1080:force_original_aspect_ratio=decrease:normalize_sar=true:upscaler=ewa_lanczos:downscaler=ewa_lanczos
• Interpolate low FPS / VFR input to smoothed constant 60 fps output:
libplacebo=fps=60:frame_mixer=mitchell_clamp
• Convert input to standard sRGB JPEG:
libplacebo=format=yuv420p:colorspace=bt470bg:color_primaries=bt709:color_trc=iec61966-2-1:range=pc
• Use higher quality debanding settings:
libplacebo=deband=true:deband_iterations=3:deband_radius=8:deband_threshold=6
• Run this filter on the CPU, on systems with Mesa installed (and with the most
expensive options disabled):
ffmpeg ... -init_hw_device vulkan:llvmpipe ... -vf libplacebo=upscaler=none:downscaler=none:peak_detect=false
• Suppress CPU-based AV1/H.274 film grain application in the decoder, in favor of doing
it with this filter. Note that this is only a gain if the frames are either already on
the GPU, or if you're using libplacebo for other purposes, since otherwise the VRAM
roundtrip will more than offset any expected speedup.
ffmpeg -export_side_data +film_grain ... -vf libplacebo=apply_filmgrain=true
• Interop with VAAPI hwdec to avoid round-tripping through RAM:
ffmpeg -init_hw_device vulkan -hwaccel vaapi -hwaccel_output_format vaapi ... -vf libplacebo
libvmaf
Calculate the VMAF (Video Multi-Method Assessment Fusion) score for a reference/distorted
pair of input videos.
The first input is the distorted video, and the second input is the reference video.
The obtained VMAF score is printed through the logging system.
It requires Netflix's vmaf library (libvmaf) as a pre-requisite. After installing the
library it can be enabled using: "./configure --enable-libvmaf".
The filter has following options:
model
A `|` delimited list of vmaf models. Each model can be configured with a number of
parameters. Default value: "version=vmaf_v0.6.1"
feature
A `|` delimited list of features. Each feature can be configured with a number of
parameters.
log_path
Set the file path to be used to store log files.
log_fmt
Set the format of the log file (xml, json, csv, or sub).
pool
Set the pool method to be used for computing vmaf. Options are "min", "harmonic_mean"
or "mean" (default).
n_threads
Set number of threads to be used when initializing libvmaf. Default value: 0, no
threads.
n_subsample
Set frame subsampling interval to be used.
This filter also supports the framesync options.
Examples
• In the examples below, a distorted video distorted.mpg is compared with a reference
file reference.mpg.
• Basic usage:
ffmpeg -i distorted.mpg -i reference.mpg -lavfi libvmaf=log_path=output.xml -f null -
• Example with multiple models:
ffmpeg -i distorted.mpg -i reference.mpg -lavfi libvmaf='model=version=vmaf_v0.6.1\\:name=vmaf|version=vmaf_v0.6.1neg\\:name=vmaf_neg' -f null -
• Example with multiple additional features:
ffmpeg -i distorted.mpg -i reference.mpg -lavfi libvmaf='feature=name=psnr|name=ciede' -f null -
• Example with options and different containers:
ffmpeg -i distorted.mpg -i reference.mkv -lavfi "[0:v]settb=AVTB,setpts=PTS-STARTPTS[main];[1:v]settb=AVTB,setpts=PTS-STARTPTS[ref];[main][ref]libvmaf=log_fmt=json:log_path=output.json" -f null -
libvmaf_cuda
This is the CUDA variant of the libvmaf filter. It only accepts CUDA frames.
It requires Netflix's vmaf library (libvmaf) as a pre-requisite. After installing the
library it can be enabled using: "./configure --enable-nonfree --enable-ffnvcodec
--enable-libvmaf".
Examples
• Basic usage showing CUVID hardware decoding and CUDA scaling with scale_cuda:
ffmpeg \
-hwaccel cuda -hwaccel_output_format cuda -codec:v av1_cuvid -i dis.obu \
-hwaccel cuda -hwaccel_output_format cuda -codec:v av1_cuvid -i ref.obu \
-filter_complex "
[0:v]scale_cuda=format=yuv420p[dis]; \
[1:v]scale_cuda=format=yuv420p[ref]; \
[dis][ref]libvmaf_cuda=log_fmt=json:log_path=output.json
" \
-f null -
limitdiff
Apply limited difference filter using second and optionally third video stream.
The filter accepts the following options:
threshold
Set the threshold to use when allowing certain differences between video streams. Any
absolute difference value lower or exact than this threshold will pick pixel
components from first video stream.
elasticity
Set the elasticity of soft thresholding when processing video streams. This value
multiplied with first one sets second threshold. Any absolute difference value
greater or exact than second threshold will pick pixel components from second video
stream. For values between those two threshold linear interpolation between first and
second video stream will be used.
reference
Enable the reference (third) video stream processing. By default is disabled. If set,
this video stream will be used for calculating absolute difference with first video
stream.
planes
Specify which planes will be processed. Defaults to all available.
Commands
This filter supports the all above options as commands except option reference.
limiter
Limits the pixel components values to the specified range [min, max].
The filter accepts the following options:
min Lower bound. Defaults to the lowest allowed value for the input.
max Upper bound. Defaults to the highest allowed value for the input.
planes
Specify which planes will be processed. Defaults to all available.
Commands
This filter supports the all above options as commands.
loop
Loop video frames.
The filter accepts the following options:
loop
Set the number of loops. Setting this value to -1 will result in infinite loops.
Default is 0.
size
Set maximal size in number of frames. Default is 0.
start
Set first frame of loop. Default is 0.
time
Set the time of loop start in seconds. Only used if option named start is set to -1.
Examples
• Loop single first frame infinitely:
loop=loop=-1:size=1:start=0
• Loop single first frame 10 times:
loop=loop=10:size=1:start=0
• Loop 10 first frames 5 times:
loop=loop=5:size=10:start=0
lut1d
Apply a 1D LUT to an input video.
The filter accepts the following options:
file
Set the 1D LUT file name.
Currently supported formats:
cube
Iridas
csp cineSpace
interp
Select interpolation mode.
Available values are:
nearest
Use values from the nearest defined point.
linear
Interpolate values using the linear interpolation.
cosine
Interpolate values using the cosine interpolation.
cubic
Interpolate values using the cubic interpolation.
spline
Interpolate values using the spline interpolation.
Commands
This filter supports the all above options as commands.
lut3d
Apply a 3D LUT to an input video.
The filter accepts the following options:
file
Set the 3D LUT file name.
Currently supported formats:
3dl AfterEffects
cube
Iridas
dat DaVinci
m3d Pandora
csp cineSpace
interp
Select interpolation mode.
Available values are:
nearest
Use values from the nearest defined point.
trilinear
Interpolate values using the 8 points defining a cube.
tetrahedral
Interpolate values using a tetrahedron.
pyramid
Interpolate values using a pyramid.
prism
Interpolate values using a prism.
Commands
This filter supports the "interp" option as commands.
lumakey
Turn certain luma values into transparency.
The filter accepts the following options:
threshold
Set the luma which will be used as base for transparency. Default value is 0.
tolerance
Set the range of luma values to be keyed out. Default value is 0.01.
softness
Set the range of softness. Default value is 0. Use this to control gradual transition
from zero to full transparency.
Commands
This filter supports same commands as options. The command accepts the same syntax of the
corresponding option.
If the specified expression is not valid, it is kept at its current value.
lut, lutrgb, lutyuv
Compute a look-up table for binding each pixel component input value to an output value,
and apply it to the input video.
lutyuv applies a lookup table to a YUV input video, lutrgb to an RGB input video.
These filters accept the following parameters:
c0 set first pixel component expression
c1 set second pixel component expression
c2 set third pixel component expression
c3 set fourth pixel component expression, corresponds to the alpha component
r set red component expression
g set green component expression
b set blue component expression
a alpha component expression
y set Y/luma component expression
u set U/Cb component expression
v set V/Cr component expression
Each of them specifies the expression to use for computing the lookup table for the
corresponding pixel component values.
The exact component associated to each of the c* options depends on the format in input.
The lut filter requires either YUV or RGB pixel formats in input, lutrgb requires RGB
pixel formats in input, and lutyuv requires YUV.
The expressions can contain the following constants and functions:
w
h The input width and height.
val The input value for the pixel component.
clipval
The input value, clipped to the minval-maxval range.
maxval
The maximum value for the pixel component.
minval
The minimum value for the pixel component.
negval
The negated value for the pixel component value, clipped to the minval-maxval range;
it corresponds to the expression "maxval-clipval+minval".
clip(val)
The computed value in val, clipped to the minval-maxval range.
gammaval(gamma)
The computed gamma correction value of the pixel component value, clipped to the
minval-maxval range. It corresponds to the expression
"pow((clipval-minval)/(maxval-minval)\,gamma)*(maxval-minval)+minval"
All expressions default to "clipval".
Commands
This filter supports same commands as options.
Examples
• Negate input video:
lutrgb="r=maxval+minval-val:g=maxval+minval-val:b=maxval+minval-val"
lutyuv="y=maxval+minval-val:u=maxval+minval-val:v=maxval+minval-val"
The above is the same as:
lutrgb="r=negval:g=negval:b=negval"
lutyuv="y=negval:u=negval:v=negval"
• Negate luma:
lutyuv=y=negval
• Remove chroma components, turning the video into a graytone image:
lutyuv="u=128:v=128"
• Apply a luma burning effect:
lutyuv="y=2*val"
• Remove green and blue components:
lutrgb="g=0:b=0"
• Set a constant alpha channel value on input:
format=rgba,lutrgb=a="maxval-minval/2"
• Correct luma gamma by a factor of 0.5:
lutyuv=y=gammaval(0.5)
• Discard least significant bits of luma:
lutyuv=y='bitand(val, 128+64+32)'
• Technicolor like effect:
lutyuv=u='(val-maxval/2)*2+maxval/2':v='(val-maxval/2)*2+maxval/2'
lut2, tlut2
The "lut2" filter takes two input streams and outputs one stream.
The "tlut2" (time lut2) filter takes two consecutive frames from one single stream.
This filter accepts the following parameters:
c0 set first pixel component expression
c1 set second pixel component expression
c2 set third pixel component expression
c3 set fourth pixel component expression, corresponds to the alpha component
d set output bit depth, only available for "lut2" filter. By default is 0, which means
bit depth is automatically picked from first input format.
The "lut2" filter also supports the framesync options.
Each of them specifies the expression to use for computing the lookup table for the
corresponding pixel component values.
The exact component associated to each of the c* options depends on the format in inputs.
The expressions can contain the following constants:
w
h The input width and height.
x The first input value for the pixel component.
y The second input value for the pixel component.
bdx The first input video bit depth.
bdy The second input video bit depth.
All expressions default to "x".
Commands
This filter supports the all above options as commands except option "d".
Examples
• Highlight differences between two RGB video streams:
lut2='ifnot(x-y,0,pow(2,bdx)-1):ifnot(x-y,0,pow(2,bdx)-1):ifnot(x-y,0,pow(2,bdx)-1)'
• Highlight differences between two YUV video streams:
lut2='ifnot(x-y,0,pow(2,bdx)-1):ifnot(x-y,pow(2,bdx-1),pow(2,bdx)-1):ifnot(x-y,pow(2,bdx-1),pow(2,bdx)-1)'
• Show max difference between two video streams:
lut2='if(lt(x,y),0,if(gt(x,y),pow(2,bdx)-1,pow(2,bdx-1))):if(lt(x,y),0,if(gt(x,y),pow(2,bdx)-1,pow(2,bdx-1))):if(lt(x,y),0,if(gt(x,y),pow(2,bdx)-1,pow(2,bdx-1)))'
maskedclamp
Clamp the first input stream with the second input and third input stream.
Returns the value of first stream to be between second input stream - "undershoot" and
third input stream + "overshoot".
This filter accepts the following options:
undershoot
Default value is 0.
overshoot
Default value is 0.
planes
Set which planes will be processed as bitmap, unprocessed planes will be copied from
first stream. By default value 0xf, all planes will be processed.
Commands
This filter supports the all above options as commands.
maskedmax
Merge the second and third input stream into output stream using absolute differences
between second input stream and first input stream and absolute difference between third
input stream and first input stream. The picked value will be from second input stream if
second absolute difference is greater than first one or from third input stream otherwise.
This filter accepts the following options:
planes
Set which planes will be processed as bitmap, unprocessed planes will be copied from
first stream. By default value 0xf, all planes will be processed.
Commands
This filter supports the all above options as commands.
maskedmerge
Merge the first input stream with the second input stream using per pixel weights in the
third input stream.
A value of 0 in the third stream pixel component means that pixel component from first
stream is returned unchanged, while maximum value (eg. 255 for 8-bit videos) means that
pixel component from second stream is returned unchanged. Intermediate values define the
amount of merging between both input stream's pixel components.
This filter accepts the following options:
planes
Set which planes will be processed as bitmap, unprocessed planes will be copied from
first stream. By default value 0xf, all planes will be processed.
Commands
This filter supports the all above options as commands.
maskedmin
Merge the second and third input stream into output stream using absolute differences
between second input stream and first input stream and absolute difference between third
input stream and first input stream. The picked value will be from second input stream if
second absolute difference is less than first one or from third input stream otherwise.
This filter accepts the following options:
planes
Set which planes will be processed as bitmap, unprocessed planes will be copied from
first stream. By default value 0xf, all planes will be processed.
Commands
This filter supports the all above options as commands.
maskedthreshold
Pick pixels comparing absolute difference of two video streams with fixed threshold.
If absolute difference between pixel component of first and second video stream is equal
or lower than user supplied threshold than pixel component from first video stream is
picked, otherwise pixel component from second video stream is picked.
This filter accepts the following options:
threshold
Set threshold used when picking pixels from absolute difference from two input video
streams.
planes
Set which planes will be processed as bitmap, unprocessed planes will be copied from
second stream. By default value 0xf, all planes will be processed.
mode
Set mode of filter operation. Can be "abs" or "diff". Default is "abs".
Commands
This filter supports the all above options as commands.
maskfun
Create mask from input video.
For example it is useful to create motion masks after "tblend" filter.
This filter accepts the following options:
low Set low threshold. Any pixel component lower or exact than this value will be set to
0.
high
Set high threshold. Any pixel component higher than this value will be set to max
value allowed for current pixel format.
planes
Set planes to filter, by default all available planes are filtered.
fill
Fill all frame pixels with this value.
sum Set max average pixel value for frame. If sum of all pixel components is higher that
this average, output frame will be completely filled with value set by fill option.
Typically useful for scene changes when used in combination with "tblend" filter.
Commands
This filter supports the all above options as commands.
mcdeint
Apply motion-compensation deinterlacing.
It needs one field per frame as input and must thus be used together with yadif=1/3 or
equivalent.
This filter accepts the following options:
mode
Set the deinterlacing mode.
It accepts one of the following values:
fast
medium
slow
use iterative motion estimation
extra_slow
like slow, but use multiple reference frames.
Default value is fast.
parity
Set the picture field parity assumed for the input video. It must be one of the
following values:
0, tff
assume top field first
1, bff
assume bottom field first
Default value is bff.
qp Set per-block quantization parameter (QP) used by the internal encoder.
Higher values should result in a smoother motion vector field but less optimal
individual vectors. Default value is 1.
median
Pick median pixel from certain rectangle defined by radius.
This filter accepts the following options:
radius
Set horizontal radius size. Default value is 1. Allowed range is integer from 1 to
127.
planes
Set which planes to process. Default is 15, which is all available planes.
radiusV
Set vertical radius size. Default value is 0. Allowed range is integer from 0 to 127.
If it is 0, value will be picked from horizontal "radius" option.
percentile
Set median percentile. Default value is 0.5. Default value of 0.5 will pick always
median values, while 0 will pick minimum values, and 1 maximum values.
Commands
This filter supports same commands as options. The command accepts the same syntax of the
corresponding option.
If the specified expression is not valid, it is kept at its current value.
mergeplanes
Merge color channel components from several video streams.
The filter accepts up to 4 input streams, and merge selected input planes to the output
video.
This filter accepts the following options:
mapping
Set input to output plane mapping. Default is 0.
The mappings is specified as a bitmap. It should be specified as a hexadecimal number
in the form 0xAa[Bb[Cc[Dd]]]. 'Aa' describes the mapping for the first plane of the
output stream. 'A' sets the number of the input stream to use (from 0 to 3), and 'a'
the plane number of the corresponding input to use (from 0 to 3). The rest of the
mappings is similar, 'Bb' describes the mapping for the output stream second plane,
'Cc' describes the mapping for the output stream third plane and 'Dd' describes the
mapping for the output stream fourth plane.
format
Set output pixel format. Default is "yuva444p".
map0s
map1s
map2s
map3s
Set input to output stream mapping for output Nth plane. Default is 0.
map0p
map1p
map2p
map3p
Set input to output plane mapping for output Nth plane. Default is 0.
Examples
• Merge three gray video streams of same width and height into single video stream:
[a0][a1][a2]mergeplanes=0x001020:yuv444p
• Merge 1st yuv444p stream and 2nd gray video stream into yuva444p video stream:
[a0][a1]mergeplanes=0x00010210:yuva444p
• Swap Y and A plane in yuva444p stream:
format=yuva444p,mergeplanes=0x03010200:yuva444p
• Swap U and V plane in yuv420p stream:
format=yuv420p,mergeplanes=0x000201:yuv420p
• Cast a rgb24 clip to yuv444p:
format=rgb24,mergeplanes=0x000102:yuv444p
mestimate
Estimate and export motion vectors using block matching algorithms. Motion vectors are
stored in frame side data to be used by other filters.
This filter accepts the following options:
method
Specify the motion estimation method. Accepts one of the following values:
esa Exhaustive search algorithm.
tss Three step search algorithm.
tdls
Two dimensional logarithmic search algorithm.
ntss
New three step search algorithm.
fss Four step search algorithm.
ds Diamond search algorithm.
hexbs
Hexagon-based search algorithm.
epzs
Enhanced predictive zonal search algorithm.
umh Uneven multi-hexagon search algorithm.
Default value is esa.
mb_size
Macroblock size. Default 16.
search_param
Search parameter. Default 7.
midequalizer
Apply Midway Image Equalization effect using two video streams.
Midway Image Equalization adjusts a pair of images to have the same histogram, while
maintaining their dynamics as much as possible. It's useful for e.g. matching exposures
from a pair of stereo cameras.
This filter has two inputs and one output, which must be of same pixel format, but may be
of different sizes. The output of filter is first input adjusted with midway histogram of
both inputs.
This filter accepts the following option:
planes
Set which planes to process. Default is 15, which is all available planes.
minterpolate
Convert the video to specified frame rate using motion interpolation.
This filter accepts the following options:
fps Specify the output frame rate. This can be rational e.g. "60000/1001". Frames are
dropped if fps is lower than source fps. Default 60.
mi_mode
Motion interpolation mode. Following values are accepted:
dup Duplicate previous or next frame for interpolating new ones.
blend
Blend source frames. Interpolated frame is mean of previous and next frames.
mci Motion compensated interpolation. Following options are effective when this mode
is selected:
mc_mode
Motion compensation mode. Following values are accepted:
obmc
Overlapped block motion compensation.
aobmc
Adaptive overlapped block motion compensation. Window weighting
coefficients are controlled adaptively according to the reliabilities of
the neighboring motion vectors to reduce oversmoothing.
Default mode is obmc.
me_mode
Motion estimation mode. Following values are accepted:
bidir
Bidirectional motion estimation. Motion vectors are estimated for each
source frame in both forward and backward directions.
bilat
Bilateral motion estimation. Motion vectors are estimated directly for
interpolated frame.
Default mode is bilat.
me The algorithm to be used for motion estimation. Following values are accepted:
esa Exhaustive search algorithm.
tss Three step search algorithm.
tdls
Two dimensional logarithmic search algorithm.
ntss
New three step search algorithm.
fss Four step search algorithm.
ds Diamond search algorithm.
hexbs
Hexagon-based search algorithm.
epzs
Enhanced predictive zonal search algorithm.
umh Uneven multi-hexagon search algorithm.
Default algorithm is epzs.
mb_size
Macroblock size. Default 16.
search_param
Motion estimation search parameter. Default 32.
vsbmc
Enable variable-size block motion compensation. Motion estimation is applied
with smaller block sizes at object boundaries in order to make them less
blurry. Default is 0 (disabled).
scd Scene change detection method. Scene change leads motion vectors to be in random
direction. Scene change detection replace interpolated frames by duplicate ones. May
not be needed for other modes. Following values are accepted:
none
Disable scene change detection.
fdiff
Frame difference. Corresponding pixel values are compared and if it satisfies
scd_threshold scene change is detected.
Default method is fdiff.
scd_threshold
Scene change detection threshold. Default is 10..
mix
Mix several video input streams into one video stream.
A description of the accepted options follows.
inputs
The number of inputs. If unspecified, it defaults to 2.
weights
Specify weight of each input video stream as sequence. Each weight is separated by
space. If number of weights is smaller than number of frames last specified weight
will be used for all remaining unset weights.
scale
Specify scale, if it is set it will be multiplied with sum of each weight multiplied
with pixel values to give final destination pixel value. By default scale is auto
scaled to sum of weights.
planes
Set which planes to filter. Default is all. Allowed range is from 0 to 15.
duration
Specify how end of stream is determined.
longest
The duration of the longest input. (default)
shortest
The duration of the shortest input.
first
The duration of the first input.
Commands
This filter supports the following commands:
weights
scale
planes
Syntax is same as option with same name.
monochrome
Convert video to gray using custom color filter.
A description of the accepted options follows.
cb Set the chroma blue spot. Allowed range is from -1 to 1. Default value is 0.
cr Set the chroma red spot. Allowed range is from -1 to 1. Default value is 0.
size
Set the color filter size. Allowed range is from .1 to 10. Default value is 1.
high
Set the highlights strength. Allowed range is from 0 to 1. Default value is 0.
Commands
This filter supports the all above options as commands.
morpho
This filter allows to apply main morphological grayscale transforms, erode and dilate with
arbitrary structures set in second input stream.
Unlike naive implementation and much slower performance in erosion and dilation filters,
when speed is critical "morpho" filter should be used instead.
A description of accepted options follows,
mode
Set morphological transform to apply, can be:
erode
dilate
open
close
gradient
tophat
blackhat
Default is "erode".
planes
Set planes to filter, by default all planes except alpha are filtered.
structure
Set which structure video frames will be processed from second input stream, can be
first or all. Default is all.
The "morpho" filter also supports the framesync options.
Commands
This filter supports same commands as options.
mpdecimate
Drop frames that do not differ greatly from the previous frame in order to reduce frame
rate.
The main use of this filter is for very-low-bitrate encoding (e.g. streaming over dialup
modem), but it could in theory be used for fixing movies that were inverse-telecined
incorrectly.
A description of the accepted options follows.
max Set the maximum number of consecutive frames which can be dropped (if positive), or
the minimum interval between dropped frames (if negative). If the value is 0, the
frame is dropped disregarding the number of previous sequentially dropped frames.
Default value is 0.
keep
Set the maximum number of consecutive similar frames to ignore before to start
dropping them. If the value is 0, the frame is dropped disregarding the number of
previous sequentially similar frames.
Default value is 0.
hi
lo
frac
Set the dropping threshold values.
Values for hi and lo are for 8x8 pixel blocks and represent actual pixel value
differences, so a threshold of 64 corresponds to 1 unit of difference for each pixel,
or the same spread out differently over the block.
A frame is a candidate for dropping if no 8x8 blocks differ by more than a threshold
of hi, and if no more than frac blocks (1 meaning the whole image) differ by more than
a threshold of lo.
Default value for hi is 64*12, default value for lo is 64*5, and default value for
frac is 0.33.
msad
Obtain the MSAD (Mean Sum of Absolute Differences) between two input videos.
This filter takes two input videos.
Both input videos must have the same resolution and pixel format for this filter to work
correctly. Also it assumes that both inputs have the same number of frames, which are
compared one by one.
The obtained per component, average, min and max MSAD is printed through the logging
system.
The filter stores the calculated MSAD of each frame in frame metadata.
This filter also supports the framesync options.
In the below example the input file main.mpg being processed is compared with the
reference file ref.mpg.
ffmpeg -i main.mpg -i ref.mpg -lavfi msad -f null -
multiply
Multiply first video stream pixels values with second video stream pixels values.
The filter accepts the following options:
scale
Set the scale applied to second video stream. By default is 1. Allowed range is from
0 to 9.
offset
Set the offset applied to second video stream. By default is 0.5. Allowed range is
from -1 to 1.
planes
Specify planes from input video stream that will be processed. By default all planes
are processed.
Commands
This filter supports same commands as options.
negate
Negate (invert) the input video.
It accepts the following option:
components
Set components to negate.
Available values for components are:
y
u
v
a
r
g
b
negate_alpha
With value 1, it negates the alpha component, if present. Default value is 0.
Commands
This filter supports same commands as options.
nlmeans
Denoise frames using Non-Local Means algorithm.
Each pixel is adjusted by looking for other pixels with similar contexts. This context
similarity is defined by comparing their surrounding patches of size pxp. Patches are
searched in an area of rxr around the pixel.
Note that the research area defines centers for patches, which means some patches will be
made of pixels outside that research area.
The filter accepts the following options.
s Set denoising strength. Default is 1.0. Must be in range [1.0, 30.0].
p Set patch size. Default is 7. Must be odd number in range [0, 99].
pc Same as p but for chroma planes.
The default value is 0 and means automatic.
r Set research size. Default is 15. Must be odd number in range [0, 99].
rc Same as r but for chroma planes.
The default value is 0 and means automatic.
nnedi
Deinterlace video using neural network edge directed interpolation.
This filter accepts the following options:
weights
Mandatory option, without binary file filter can not work. Currently file can be
found here:
https://github.com/dubhater/vapoursynth-nnedi3/blob/master/src/nnedi3_weights.bin
deint
Set which frames to deinterlace, by default it is "all". Can be "all" or
"interlaced".
field
Set mode of operation.
Can be one of the following:
af Use frame flags, both fields.
a Use frame flags, single field.
t Use top field only.
b Use bottom field only.
tf Use both fields, top first.
bf Use both fields, bottom first.
planes
Set which planes to process, by default filter process all frames.
nsize
Set size of local neighborhood around each pixel, used by the predictor neural
network.
Can be one of the following:
s8x6
s16x6
s32x6
s48x6
s8x4
s16x4
s32x4
nns Set the number of neurons in predictor neural network. Can be one of the following:
n16
n32
n64
n128
n256
qual
Controls the number of different neural network predictions that are blended together
to compute the final output value. Can be "fast", default or "slow".
etype
Set which set of weights to use in the predictor. Can be one of the following:
a, abs
weights trained to minimize absolute error
s, mse
weights trained to minimize squared error
pscrn
Controls whether or not the prescreener neural network is used to decide which pixels
should be processed by the predictor neural network and which can be handled by simple
cubic interpolation. The prescreener is trained to know whether cubic interpolation
will be sufficient for a pixel or whether it should be predicted by the predictor nn.
The computational complexity of the prescreener nn is much less than that of the
predictor nn. Since most pixels can be handled by cubic interpolation, using the
prescreener generally results in much faster processing. The prescreener is pretty
accurate, so the difference between using it and not using it is almost always
unnoticeable.
Can be one of the following:
none
original
new
new2
new3
Default is "new".
Commands
This filter supports same commands as options, excluding weights option.
noformat
Force libavfilter not to use any of the specified pixel formats for the input to the next
filter.
It accepts the following parameters:
pix_fmts
A '|'-separated list of pixel format names, such as pix_fmts=yuv420p|monow|rgb24".
Examples
• Force libavfilter to use a format different from yuv420p for the input to the vflip
filter:
noformat=pix_fmts=yuv420p,vflip
• Convert the input video to any of the formats not contained in the list:
noformat=yuv420p|yuv444p|yuv410p
noise
Add noise on video input frame.
The filter accepts the following options:
all_seed
c0_seed
c1_seed
c2_seed
c3_seed
Set noise seed for specific pixel component or all pixel components in case of
all_seed. Default value is 123457.
all_strength, alls
c0_strength, c0s
c1_strength, c1s
c2_strength, c2s
c3_strength, c3s
Set noise strength for specific pixel component or all pixel components in case
all_strength. Default value is 0. Allowed range is [0, 100].
all_flags, allf
c0_flags, c0f
c1_flags, c1f
c2_flags, c2f
c3_flags, c3f
Set pixel component flags or set flags for all components if all_flags. Available
values for component flags are:
a averaged temporal noise (smoother)
p mix random noise with a (semi)regular pattern
t temporal noise (noise pattern changes between frames)
u uniform noise (gaussian otherwise)
Examples
Add temporal and uniform noise to input video:
noise=alls=20:allf=t+u
normalize
Normalize RGB video (aka histogram stretching, contrast stretching). See:
https://en.wikipedia.org/wiki/Normalization_(image_processing)
For each channel of each frame, the filter computes the input range and maps it linearly
to the user-specified output range. The output range defaults to the full dynamic range
from pure black to pure white.
Temporal smoothing can be used on the input range to reduce flickering (rapid changes in
brightness) caused when small dark or bright objects enter or leave the scene. This is
similar to the auto-exposure (automatic gain control) on a video camera, and, like a video
camera, it may cause a period of over- or under-exposure of the video.
The R,G,B channels can be normalized independently, which may cause some color shifting,
or linked together as a single channel, which prevents color shifting. Linked
normalization preserves hue. Independent normalization does not, so it can be used to
remove some color casts. Independent and linked normalization can be combined in any
ratio.
The normalize filter accepts the following options:
blackpt
whitept
Colors which define the output range. The minimum input value is mapped to the
blackpt. The maximum input value is mapped to the whitept. The defaults are black and
white respectively. Specifying white for blackpt and black for whitept will give
color-inverted, normalized video. Shades of grey can be used to reduce the dynamic
range (contrast). Specifying saturated colors here can create some interesting
effects.
smoothing
The number of previous frames to use for temporal smoothing. The input range of each
channel is smoothed using a rolling average over the current frame and the smoothing
previous frames. The default is 0 (no temporal smoothing).
independence
Controls the ratio of independent (color shifting) channel normalization to linked
(color preserving) normalization. 0.0 is fully linked, 1.0 is fully independent.
Defaults to 1.0 (fully independent).
strength
Overall strength of the filter. 1.0 is full strength. 0.0 is a rather expensive no-op.
Defaults to 1.0 (full strength).
Commands
This filter supports same commands as options, excluding smoothing option. The command
accepts the same syntax of the corresponding option.
If the specified expression is not valid, it is kept at its current value.
Examples
Stretch video contrast to use the full dynamic range, with no temporal smoothing; may
flicker depending on the source content:
normalize=blackpt=black:whitept=white:smoothing=0
As above, but with 50 frames of temporal smoothing; flicker should be reduced, depending
on the source content:
normalize=blackpt=black:whitept=white:smoothing=50
As above, but with hue-preserving linked channel normalization:
normalize=blackpt=black:whitept=white:smoothing=50:independence=0
As above, but with half strength:
normalize=blackpt=black:whitept=white:smoothing=50:independence=0:strength=0.5
Map the darkest input color to red, the brightest input color to cyan:
normalize=blackpt=red:whitept=cyan
null
Pass the video source unchanged to the output.
ocr
Optical Character Recognition
This filter uses Tesseract for optical character recognition. To enable compilation of
this filter, you need to configure FFmpeg with "--enable-libtesseract".
It accepts the following options:
datapath
Set datapath to tesseract data. Default is to use whatever was set at installation.
language
Set language, default is "eng".
whitelist
Set character whitelist.
blacklist
Set character blacklist.
The filter exports recognized text as the frame metadata "lavfi.ocr.text". The filter
exports confidence of recognized words as the frame metadata "lavfi.ocr.confidence".
ocv
Apply a video transform using libopencv.
To enable this filter, install the libopencv library and headers and configure FFmpeg with
"--enable-libopencv".
It accepts the following parameters:
filter_name
The name of the libopencv filter to apply.
filter_params
The parameters to pass to the libopencv filter. If not specified, the default values
are assumed.
Refer to the official libopencv documentation for more precise information:
<http://docs.opencv.org/master/modules/imgproc/doc/filtering.html>
Several libopencv filters are supported; see the following subsections.
dilate
Dilate an image by using a specific structuring element. It corresponds to the libopencv
function "cvDilate".
It accepts the parameters: struct_el|nb_iterations.
struct_el represents a structuring element, and has the syntax:
colsxrows+anchor_xxanchor_y/shape
cols and rows represent the number of columns and rows of the structuring element,
anchor_x and anchor_y the anchor point, and shape the shape for the structuring element.
shape must be "rect", "cross", "ellipse", or "custom".
If the value for shape is "custom", it must be followed by a string of the form
"=filename". The file with name filename is assumed to represent a binary image, with each
printable character corresponding to a bright pixel. When a custom shape is used, cols and
rows are ignored, the number or columns and rows of the read file are assumed instead.
The default value for struct_el is "3x3+0x0/rect".
nb_iterations specifies the number of times the transform is applied to the image, and
defaults to 1.
Some examples:
# Use the default values
ocv=dilate
# Dilate using a structuring element with a 5x5 cross, iterating two times
ocv=filter_name=dilate:filter_params=5x5+2x2/cross|2
# Read the shape from the file diamond.shape, iterating two times.
# The file diamond.shape may contain a pattern of characters like this
# *
# ***
# *****
# ***
# *
# The specified columns and rows are ignored
# but the anchor point coordinates are not
ocv=dilate:0x0+2x2/custom=diamond.shape|2
erode
Erode an image by using a specific structuring element. It corresponds to the libopencv
function "cvErode".
It accepts the parameters: struct_el:nb_iterations, with the same syntax and semantics as
the dilate filter.
smooth
Smooth the input video.
The filter takes the following parameters: type|param1|param2|param3|param4.
type is the type of smooth filter to apply, and must be one of the following values:
"blur", "blur_no_scale", "median", "gaussian", or "bilateral". The default value is
"gaussian".
The meaning of param1, param2, param3, and param4 depends on the smooth type. param1 and
param2 accept integer positive values or 0. param3 and param4 accept floating point
values.
The default value for param1 is 3. The default value for the other parameters is 0.
These parameters correspond to the parameters assigned to the libopencv function
"cvSmooth".
oscilloscope
2D Video Oscilloscope.
Useful to measure spatial impulse, step responses, chroma delays, etc.
It accepts the following parameters:
x Set scope center x position.
y Set scope center y position.
s Set scope size, relative to frame diagonal.
t Set scope tilt/rotation.
o Set trace opacity.
tx Set trace center x position.
ty Set trace center y position.
tw Set trace width, relative to width of frame.
th Set trace height, relative to height of frame.
c Set which components to trace. By default it traces first three components.
g Draw trace grid. By default is enabled.
st Draw some statistics. By default is enabled.
sc Draw scope. By default is enabled.
Commands
This filter supports same commands as options. The command accepts the same syntax of the
corresponding option.
If the specified expression is not valid, it is kept at its current value.
Examples
• Inspect full first row of video frame.
oscilloscope=x=0.5:y=0:s=1
• Inspect full last row of video frame.
oscilloscope=x=0.5:y=1:s=1
• Inspect full 5th line of video frame of height 1080.
oscilloscope=x=0.5:y=5/1080:s=1
• Inspect full last column of video frame.
oscilloscope=x=1:y=0.5:s=1:t=1
overlay
Overlay one video on top of another.
It takes two inputs and has one output. The first input is the "main" video on which the
second input is overlaid.
It accepts the following parameters:
A description of the accepted options follows.
x
y Set the expression for the x and y coordinates of the overlaid video on the main
video. Default value is "0" for both expressions. In case the expression is invalid,
it is set to a huge value (meaning that the overlay will not be displayed within the
output visible area).
eof_action
See framesync.
eval
Set when the expressions for x, and y are evaluated.
It accepts the following values:
init
only evaluate expressions once during the filter initialization or when a command
is processed
frame
evaluate expressions for each incoming frame
Default value is frame.
shortest
See framesync.
format
Set the format for the output video.
It accepts the following values:
yuv420
force YUV 4:2:0 8-bit planar output
yuv420p10
force YUV 4:2:0 10-bit planar output
yuv422
force YUV 4:2:2 8-bit planar output
yuv422p10
force YUV 4:2:2 10-bit planar output
yuv444
force YUV 4:4:4 8-bit planar output
yuv444p10
force YUV 4:4:4 10-bit planar output
rgb force RGB 8-bit packed output
gbrp
force RGB 8-bit planar output
auto
automatically pick format
Default value is yuv420.
repeatlast
See framesync.
alpha
Set format of alpha of the overlaid video, it can be straight or premultiplied.
Default is straight.
The x, and y expressions can contain the following parameters.
main_w, W
main_h, H
The main input width and height.
overlay_w, w
overlay_h, h
The overlay input width and height.
x
y The computed values for x and y. They are evaluated for each new frame.
hsub
vsub
horizontal and vertical chroma subsample values of the output format. For example for
the pixel format "yuv422p" hsub is 2 and vsub is 1.
n the number of input frame, starting from 0
pos the position in the file of the input frame, NAN if unknown; deprecated, do not use
t The timestamp, expressed in seconds. It's NAN if the input timestamp is unknown.
This filter also supports the framesync options.
Note that the n, t variables are available only when evaluation is done per frame, and
will evaluate to NAN when eval is set to init.
Be aware that frames are taken from each input video in timestamp order, hence, if their
initial timestamps differ, it is a good idea to pass the two inputs through a
setpts=PTS-STARTPTS filter to have them begin in the same zero timestamp, as the example
for the movie filter does.
You can chain together more overlays but you should test the efficiency of such approach.
Commands
This filter supports the following commands:
x
y Modify the x and y of the overlay input. The command accepts the same syntax of the
corresponding option.
If the specified expression is not valid, it is kept at its current value.
Examples
• Draw the overlay at 10 pixels from the bottom right corner of the main video:
overlay=main_w-overlay_w-10:main_h-overlay_h-10
Using named options the example above becomes:
overlay=x=main_w-overlay_w-10:y=main_h-overlay_h-10
• Insert a transparent PNG logo in the bottom left corner of the input, using the ffmpeg
tool with the "-filter_complex" option:
ffmpeg -i input -i logo -filter_complex 'overlay=10:main_h-overlay_h-10' output
• Insert 2 different transparent PNG logos (second logo on bottom right corner) using
the ffmpeg tool:
ffmpeg -i input -i logo1 -i logo2 -filter_complex 'overlay=x=10:y=H-h-10,overlay=x=W-w-10:y=H-h-10' output
• Add a transparent color layer on top of the main video; "WxH" must specify the size of
the main input to the overlay filter:
color=color=red@.3:size=WxH [over]; [in][over] overlay [out]
• Play an original video and a filtered version (here with the deshake filter) side by
side using the ffplay tool:
ffplay input.avi -vf 'split[a][b]; [a]pad=iw*2:ih[src]; [b]deshake[filt]; [src][filt]overlay=w'
The above command is the same as:
ffplay input.avi -vf 'split[b], pad=iw*2[src], [b]deshake, [src]overlay=w'
• Make a sliding overlay appearing from the left to the right top part of the screen
starting since time 2:
overlay=x='if(gte(t,2), -w+(t-2)*20, NAN)':y=0
• Compose output by putting two input videos side to side:
ffmpeg -i left.avi -i right.avi -filter_complex "
nullsrc=size=200x100 [background];
[0:v] setpts=PTS-STARTPTS, scale=100x100 [left];
[1:v] setpts=PTS-STARTPTS, scale=100x100 [right];
[background][left] overlay=shortest=1 [background+left];
[background+left][right] overlay=shortest=1:x=100 [left+right]
"
• Mask 10-20 seconds of a video by applying the delogo filter to a section
ffmpeg -i test.avi -codec:v:0 wmv2 -ar 11025 -b:v 9000k
-vf '[in]split[split_main][split_delogo];[split_delogo]trim=start=360:end=371,delogo=0:0:640:480[delogoed];[split_main][delogoed]overlay=eof_action=pass[out]'
masked.avi
• Chain several overlays in cascade:
nullsrc=s=200x200 [bg];
testsrc=s=100x100, split=4 [in0][in1][in2][in3];
[in0] lutrgb=r=0, [bg] overlay=0:0 [mid0];
[in1] lutrgb=g=0, [mid0] overlay=100:0 [mid1];
[in2] lutrgb=b=0, [mid1] overlay=0:100 [mid2];
[in3] null, [mid2] overlay=100:100 [out0]
overlay_cuda
Overlay one video on top of another.
This is the CUDA variant of the overlay filter. It only accepts CUDA frames. The
underlying input pixel formats have to match.
It takes two inputs and has one output. The first input is the "main" video on which the
second input is overlaid.
It accepts the following parameters:
x
y Set expressions for the x and y coordinates of the overlaid video on the main video.
They can contain the following parameters:
main_w, W
main_h, H
The main input width and height.
overlay_w, w
overlay_h, h
The overlay input width and height.
x
y The computed values for x and y. They are evaluated for each new frame.
n The ordinal index of the main input frame, starting from 0.
pos The byte offset position in the file of the main input frame, NAN if unknown.
Deprecated, do not use.
t The timestamp of the main input frame, expressed in seconds, NAN if unknown.
Default value is "0" for both expressions.
eval
Set when the expressions for x and y are evaluated.
It accepts the following values:
init
Evaluate expressions once during filter initialization or when a command is
processed.
frame
Evaluate expressions for each incoming frame
Default value is frame.
eof_action
See framesync.
shortest
See framesync.
repeatlast
See framesync.
This filter also supports the framesync options.
owdenoise
Apply Overcomplete Wavelet denoiser.
The filter accepts the following options:
depth
Set depth.
Larger depth values will denoise lower frequency components more, but slow down
filtering.
Must be an int in the range 8-16, default is 8.
luma_strength, ls
Set luma strength.
Must be a double value in the range 0-1000, default is 1.0.
chroma_strength, cs
Set chroma strength.
Must be a double value in the range 0-1000, default is 1.0.
pad
Add paddings to the input image, and place the original input at the provided x, y
coordinates.
It accepts the following parameters:
width, w
height, h
Specify an expression for the size of the output image with the paddings added. If the
value for width or height is 0, the corresponding input size is used for the output.
The width expression can reference the value set by the height expression, and vice
versa.
The default value of width and height is 0.
x
y Specify the offsets to place the input image at within the padded area, with respect
to the top/left border of the output image.
The x expression can reference the value set by the y expression, and vice versa.
The default value of x and y is 0.
If x or y evaluate to a negative number, they'll be changed so the input image is
centered on the padded area.
color
Specify the color of the padded area. For the syntax of this option, check the "Color"
section in the ffmpeg-utils manual.
The default value of color is "black".
eval
Specify when to evaluate width, height, x and y expression.
It accepts the following values:
init
Only evaluate expressions once during the filter initialization or when a command
is processed.
frame
Evaluate expressions for each incoming frame.
Default value is init.
aspect
Pad to aspect instead to a resolution.
The value for the width, height, x, and y options are expressions containing the following
constants:
in_w
in_h
The input video width and height.
iw
ih These are the same as in_w and in_h.
out_w
out_h
The output width and height (the size of the padded area), as specified by the width
and height expressions.
ow
oh These are the same as out_w and out_h.
x
y The x and y offsets as specified by the x and y expressions, or NAN if not yet
specified.
a same as iw / ih
sar input sample aspect ratio
dar input display aspect ratio, it is the same as (iw / ih) * sar
hsub
vsub
The horizontal and vertical chroma subsample values. For example for the pixel format
"yuv422p" hsub is 2 and vsub is 1.
Examples
• Add paddings with the color "violet" to the input video. The output video size is
640x480, and the top-left corner of the input video is placed at column 0, row 40
pad=640:480:0:40:violet
The example above is equivalent to the following command:
pad=width=640:height=480:x=0:y=40:color=violet
• Pad the input to get an output with dimensions increased by 3/2, and put the input
video at the center of the padded area:
pad="3/2*iw:3/2*ih:(ow-iw)/2:(oh-ih)/2"
• Pad the input to get a squared output with size equal to the maximum value between the
input width and height, and put the input video at the center of the padded area:
pad="max(iw\,ih):ow:(ow-iw)/2:(oh-ih)/2"
• Pad the input to get a final w/h ratio of 16:9:
pad="ih*16/9:ih:(ow-iw)/2:(oh-ih)/2"
• In case of anamorphic video, in order to set the output display aspect correctly, it
is necessary to use sar in the expression, according to the relation:
(ih * X / ih) * sar = output_dar
X = output_dar / sar
Thus the previous example needs to be modified to:
pad="ih*16/9/sar:ih:(ow-iw)/2:(oh-ih)/2"
• Double the output size and put the input video in the bottom-right corner of the
output padded area:
pad="2*iw:2*ih:ow-iw:oh-ih"
palettegen
Generate one palette for a whole video stream.
It accepts the following options:
max_colors
Set the maximum number of colors to quantize in the palette. Note: the palette will
still contain 256 colors; the unused palette entries will be black.
reserve_transparent
Create a palette of 255 colors maximum and reserve the last one for transparency.
Reserving the transparency color is useful for GIF optimization. If not set, the
maximum of colors in the palette will be 256. You probably want to disable this option
for a standalone image. Set by default.
transparency_color
Set the color that will be used as background for transparency.
stats_mode
Set statistics mode.
It accepts the following values:
full
Compute full frame histograms.
diff
Compute histograms only for the part that differs from previous frame. This might
be relevant to give more importance to the moving part of your input if the
background is static.
single
Compute new histogram for each frame.
Default value is full.
The filter also exports the frame metadata "lavfi.color_quant_ratio" ("nb_color_in /
nb_color_out") which you can use to evaluate the degree of color quantization of the
palette. This information is also visible at info logging level.
Examples
• Generate a representative palette of a given video using ffmpeg:
ffmpeg -i input.mkv -vf palettegen palette.png
paletteuse
Use a palette to downsample an input video stream.
The filter takes two inputs: one video stream and a palette. The palette must be a 256
pixels image.
It accepts the following options:
dither
Select dithering mode. Available algorithms are:
bayer
Ordered 8x8 bayer dithering (deterministic)
heckbert
Dithering as defined by Paul Heckbert in 1982 (simple error diffusion). Note:
this dithering is sometimes considered "wrong" and is included as a reference.
floyd_steinberg
Floyd and Steingberg dithering (error diffusion)
sierra2
Frankie Sierra dithering v2 (error diffusion)
sierra2_4a
Frankie Sierra dithering v2 "Lite" (error diffusion)
sierra3
Frankie Sierra dithering v3 (error diffusion)
burkes
Burkes dithering (error diffusion)
atkinson
Atkinson dithering by Bill Atkinson at Apple Computer (error diffusion)
none
Disable dithering.
Default is sierra2_4a.
bayer_scale
When bayer dithering is selected, this option defines the scale of the pattern (how
much the crosshatch pattern is visible). A low value means more visible pattern for
less banding, and higher value means less visible pattern at the cost of more banding.
The option must be an integer value in the range [0,5]. Default is 2.
diff_mode
If set, define the zone to process
rectangle
Only the changing rectangle will be reprocessed. This is similar to GIF
cropping/offsetting compression mechanism. This option can be useful for speed if
only a part of the image is changing, and has use cases such as limiting the scope
of the error diffusal dither to the rectangle that bounds the moving scene (it
leads to more deterministic output if the scene doesn't change much, and as a
result less moving noise and better GIF compression).
Default is none.
new Take new palette for each output frame.
alpha_threshold
Sets the alpha threshold for transparency. Alpha values above this threshold will be
treated as completely opaque, and values below this threshold will be treated as
completely transparent.
The option must be an integer value in the range [0,255]. Default is 128.
Examples
• Use a palette (generated for example with palettegen) to encode a GIF using ffmpeg:
ffmpeg -i input.mkv -i palette.png -lavfi paletteuse output.gif
perspective
Correct perspective of video not recorded perpendicular to the screen.
A description of the accepted parameters follows.
x0
y0
x1
y1
x2
y2
x3
y3 Set coordinates expression for top left, top right, bottom left and bottom right
corners. Default values are "0:0:W:0:0:H:W:H" with which perspective will remain
unchanged. If the "sense" option is set to "source", then the specified points will
be sent to the corners of the destination. If the "sense" option is set to
"destination", then the corners of the source will be sent to the specified
coordinates.
The expressions can use the following variables:
W
H the width and height of video frame.
in Input frame count.
on Output frame count.
interpolation
Set interpolation for perspective correction.
It accepts the following values:
linear
cubic
Default value is linear.
sense
Set interpretation of coordinate options.
It accepts the following values:
0, source
Send point in the source specified by the given coordinates to the corners of the
destination.
1, destination
Send the corners of the source to the point in the destination specified by the
given coordinates.
Default value is source.
eval
Set when the expressions for coordinates x0,y0,...x3,y3 are evaluated.
It accepts the following values:
init
only evaluate expressions once during the filter initialization or when a command
is processed
frame
evaluate expressions for each incoming frame
Default value is init.
phase
Delay interlaced video by one field time so that the field order changes.
The intended use is to fix PAL movies that have been captured with the opposite field
order to the film-to-video transfer.
A description of the accepted parameters follows.
mode
Set phase mode.
It accepts the following values:
t Capture field order top-first, transfer bottom-first. Filter will delay the
bottom field.
b Capture field order bottom-first, transfer top-first. Filter will delay the top
field.
p Capture and transfer with the same field order. This mode only exists for the
documentation of the other options to refer to, but if you actually select it, the
filter will faithfully do nothing.
a Capture field order determined automatically by field flags, transfer opposite.
Filter selects among t and b modes on a frame by frame basis using field flags. If
no field information is available, then this works just like u.
u Capture unknown or varying, transfer opposite. Filter selects among t and b on a
frame by frame basis by analyzing the images and selecting the alternative that
produces best match between the fields.
T Capture top-first, transfer unknown or varying. Filter selects among t and p
using image analysis.
B Capture bottom-first, transfer unknown or varying. Filter selects among b and p
using image analysis.
A Capture determined by field flags, transfer unknown or varying. Filter selects
among t, b and p using field flags and image analysis. If no field information is
available, then this works just like U. This is the default mode.
U Both capture and transfer unknown or varying. Filter selects among t, b and p
using image analysis only.
Commands
This filter supports the all above options as commands.
photosensitivity
Reduce various flashes in video, so to help users with epilepsy.
It accepts the following options:
frames, f
Set how many frames to use when filtering. Default is 30.
threshold, t
Set detection threshold factor. Default is 1. Lower is stricter.
skip
Set how many pixels to skip when sampling frames. Default is 1. Allowed range is from
1 to 1024.
bypass
Leave frames unchanged. Default is disabled.
pixdesctest
Pixel format descriptor test filter, mainly useful for internal testing. The output video
should be equal to the input video.
For example:
format=monow, pixdesctest
can be used to test the monowhite pixel format descriptor definition.
pixelize
Apply pixelization to video stream.
The filter accepts the following options:
width, w
height, h
Set block dimensions that will be used for pixelization. Default value is 16.
mode, m
Set the mode of pixelization used.
Possible values are:
avg
min
max
Default value is "avg".
planes, p
Set what planes to filter. Default is to filter all planes.
Commands
This filter supports all options as commands.
pixscope
Display sample values of color channels. Mainly useful for checking color and levels.
Minimum supported resolution is 640x480.
The filters accept the following options:
x Set scope X position, relative offset on X axis.
y Set scope Y position, relative offset on Y axis.
w Set scope width.
h Set scope height.
o Set window opacity. This window also holds statistics about pixel area.
wx Set window X position, relative offset on X axis.
wy Set window Y position, relative offset on Y axis.
Commands
This filter supports same commands as options.
pp
Enable the specified chain of postprocessing subfilters using libpostproc. This library
should be automatically selected with a GPL build ("--enable-gpl"). Subfilters must be
separated by '/' and can be disabled by prepending a '-'. Each subfilter and some options
have a short and a long name that can be used interchangeably, i.e. dr/dering are the
same.
The filters accept the following options:
subfilters
Set postprocessing subfilters string.
All subfilters share common options to determine their scope:
a/autoq
Honor the quality commands for this subfilter.
c/chrom
Do chrominance filtering, too (default).
y/nochrom
Do luma filtering only (no chrominance).
n/noluma
Do chrominance filtering only (no luma).
These options can be appended after the subfilter name, separated by a '|'.
Available subfilters are:
hb/hdeblock[|difference[|flatness]]
Horizontal deblocking filter
difference
Difference factor where higher values mean more deblocking (default: 32).
flatness
Flatness threshold where lower values mean more deblocking (default: 39).
vb/vdeblock[|difference[|flatness]]
Vertical deblocking filter
difference
Difference factor where higher values mean more deblocking (default: 32).
flatness
Flatness threshold where lower values mean more deblocking (default: 39).
ha/hadeblock[|difference[|flatness]]
Accurate horizontal deblocking filter
difference
Difference factor where higher values mean more deblocking (default: 32).
flatness
Flatness threshold where lower values mean more deblocking (default: 39).
va/vadeblock[|difference[|flatness]]
Accurate vertical deblocking filter
difference
Difference factor where higher values mean more deblocking (default: 32).
flatness
Flatness threshold where lower values mean more deblocking (default: 39).
The horizontal and vertical deblocking filters share the difference and flatness values so
you cannot set different horizontal and vertical thresholds.
h1/x1hdeblock
Experimental horizontal deblocking filter
v1/x1vdeblock
Experimental vertical deblocking filter
dr/dering
Deringing filter
tn/tmpnoise[|threshold1[|threshold2[|threshold3]]], temporal noise reducer
threshold1
larger -> stronger filtering
threshold2
larger -> stronger filtering
threshold3
larger -> stronger filtering
al/autolevels[:f/fullyrange], automatic brightness / contrast correction
f/fullyrange
Stretch luma to "0-255".
lb/linblenddeint
Linear blend deinterlacing filter that deinterlaces the given block by filtering all
lines with a "(1 2 1)" filter.
li/linipoldeint
Linear interpolating deinterlacing filter that deinterlaces the given block by
linearly interpolating every second line.
ci/cubicipoldeint
Cubic interpolating deinterlacing filter deinterlaces the given block by cubically
interpolating every second line.
md/mediandeint
Median deinterlacing filter that deinterlaces the given block by applying a median
filter to every second line.
fd/ffmpegdeint
FFmpeg deinterlacing filter that deinterlaces the given block by filtering every
second line with a "(-1 4 2 4 -1)" filter.
l5/lowpass5
Vertically applied FIR lowpass deinterlacing filter that deinterlaces the given block
by filtering all lines with a "(-1 2 6 2 -1)" filter.
fq/forceQuant[|quantizer]
Overrides the quantizer table from the input with the constant quantizer you specify.
quantizer
Quantizer to use
de/default
Default pp filter combination ("hb|a,vb|a,dr|a")
fa/fast
Fast pp filter combination ("h1|a,v1|a,dr|a")
ac High quality pp filter combination ("ha|a|128|7,va|a,dr|a")
Examples
• Apply horizontal and vertical deblocking, deringing and automatic brightness/contrast:
pp=hb/vb/dr/al
• Apply default filters without brightness/contrast correction:
pp=de/-al
• Apply default filters and temporal denoiser:
pp=default/tmpnoise|1|2|3
• Apply deblocking on luma only, and switch vertical deblocking on or off automatically
depending on available CPU time:
pp=hb|y/vb|a
pp7
Apply Postprocessing filter 7. It is variant of the spp filter, similar to spp = 6 with 7
point DCT, where only the center sample is used after IDCT.
The filter accepts the following options:
qp Force a constant quantization parameter. It accepts an integer in range 0 to 63. If
not set, the filter will use the QP from the video stream (if available).
mode
Set thresholding mode. Available modes are:
hard
Set hard thresholding.
soft
Set soft thresholding (better de-ringing effect, but likely blurrier).
medium
Set medium thresholding (good results, default).
premultiply
Apply alpha premultiply effect to input video stream using first plane of second stream as
alpha.
Both streams must have same dimensions and same pixel format.
The filter accepts the following option:
planes
Set which planes will be processed, unprocessed planes will be copied. By default
value 0xf, all planes will be processed.
inplace
Do not require 2nd input for processing, instead use alpha plane from input stream.
prewitt
Apply prewitt operator to input video stream.
The filter accepts the following option:
planes
Set which planes will be processed, unprocessed planes will be copied. By default
value 0xf, all planes will be processed.
scale
Set value which will be multiplied with filtered result.
delta
Set value which will be added to filtered result.
Commands
This filter supports the all above options as commands.
pseudocolor
Alter frame colors in video with pseudocolors.
This filter accepts the following options:
c0 set pixel first component expression
c1 set pixel second component expression
c2 set pixel third component expression
c3 set pixel fourth component expression, corresponds to the alpha component
index, i
set component to use as base for altering colors
preset, p
Pick one of built-in LUTs. By default is set to none.
Available LUTs:
magma
inferno
plasma
viridis
turbo
cividis
range1
range2
shadows
highlights
solar
nominal
preferred
total
spectral
cool
heat
fiery
blues
green
helix
opacity
Set opacity of output colors. Allowed range is from 0 to 1. Default value is set to
1.
Each of the expression options specifies the expression to use for computing the lookup
table for the corresponding pixel component values.
The expressions can contain the following constants and functions:
w
h The input width and height.
val The input value for the pixel component.
ymin, umin, vmin, amin
The minimum allowed component value.
ymax, umax, vmax, amax
The maximum allowed component value.
All expressions default to "val".
Commands
This filter supports the all above options as commands.
Examples
• Change too high luma values to gradient:
pseudocolor="'if(between(val,ymax,amax),lerp(ymin,ymax,(val-ymax)/(amax-ymax)),-1):if(between(val,ymax,amax),lerp(umax,umin,(val-ymax)/(amax-ymax)),-1):if(between(val,ymax,amax),lerp(vmin,vmax,(val-ymax)/(amax-ymax)),-1):-1'"
psnr
Obtain the average, maximum and minimum PSNR (Peak Signal to Noise Ratio) between two
input videos.
This filter takes in input two input videos, the first input is considered the "main"
source and is passed unchanged to the output. The second input is used as a "reference"
video for computing the PSNR.
Both video inputs must have the same resolution and pixel format for this filter to work
correctly. Also it assumes that both inputs have the same number of frames, which are
compared one by one.
The obtained average PSNR is printed through the logging system.
The filter stores the accumulated MSE (mean squared error) of each frame, and at the end
of the processing it is averaged across all frames equally, and the following formula is
applied to obtain the PSNR:
PSNR = 10*log10(MAX^2/MSE)
Where MAX is the average of the maximum values of each component of the image.
The description of the accepted parameters follows.
stats_file, f
If specified the filter will use the named file to save the PSNR of each individual
frame. When filename equals "-" the data is sent to standard output.
stats_version
Specifies which version of the stats file format to use. Details of each format are
written below. Default value is 1.
stats_add_max
Determines whether the max value is output to the stats log. Default value is 0.
Requires stats_version >= 2. If this is set and stats_version < 2, the filter will
return an error.
This filter also supports the framesync options.
The file printed if stats_file is selected, contains a sequence of key/value pairs of the
form key:value for each compared couple of frames.
If a stats_version greater than 1 is specified, a header line precedes the list of per-
frame-pair stats, with key value pairs following the frame format with the following
parameters:
psnr_log_version
The version of the log file format. Will match stats_version.
fields
A comma separated list of the per-frame-pair parameters included in the log.
A description of each shown per-frame-pair parameter follows:
n sequential number of the input frame, starting from 1
mse_avg
Mean Square Error pixel-by-pixel average difference of the compared frames, averaged
over all the image components.
mse_y, mse_u, mse_v, mse_r, mse_g, mse_b, mse_a
Mean Square Error pixel-by-pixel average difference of the compared frames for the
component specified by the suffix.
psnr_y, psnr_u, psnr_v, psnr_r, psnr_g, psnr_b, psnr_a
Peak Signal to Noise ratio of the compared frames for the component specified by the
suffix.
max_avg, max_y, max_u, max_v
Maximum allowed value for each channel, and average over all channels.
Examples
• For example:
movie=ref_movie.mpg, setpts=PTS-STARTPTS [main];
[main][ref] psnr="stats_file=stats.log" [out]
On this example the input file being processed is compared with the reference file
ref_movie.mpg. The PSNR of each individual frame is stored in stats.log.
• Another example with different containers:
ffmpeg -i main.mpg -i ref.mkv -lavfi "[0:v]settb=AVTB,setpts=PTS-STARTPTS[main];[1:v]settb=AVTB,setpts=PTS-STARTPTS[ref];[main][ref]psnr" -f null -
pullup
Pulldown reversal (inverse telecine) filter, capable of handling mixed hard-telecine,
24000/1001 fps progressive, and 30000/1001 fps progressive content.
The pullup filter is designed to take advantage of future context in making its decisions.
This filter is stateless in the sense that it does not lock onto a pattern to follow, but
it instead looks forward to the following fields in order to identify matches and rebuild
progressive frames.
To produce content with an even framerate, insert the fps filter after pullup, use
"fps=24000/1001" if the input frame rate is 29.97fps, "fps=24" for 30fps and the (rare)
telecined 25fps input.
The filter accepts the following options:
jl
jr
jt
jb These options set the amount of "junk" to ignore at the left, right, top, and bottom
of the image, respectively. Left and right are in units of 8 pixels, while top and
bottom are in units of 2 lines. The default is 8 pixels on each side.
sb Set the strict breaks. Setting this option to 1 will reduce the chances of filter
generating an occasional mismatched frame, but it may also cause an excessive number
of frames to be dropped during high motion sequences. Conversely, setting it to -1
will make filter match fields more easily. This may help processing of video where
there is slight blurring between the fields, but may also cause there to be interlaced
frames in the output. Default value is 0.
mp Set the metric plane to use. It accepts the following values:
l Use luma plane.
u Use chroma blue plane.
v Use chroma red plane.
This option may be set to use chroma plane instead of the default luma plane for doing
filter's computations. This may improve accuracy on very clean source material, but
more likely will decrease accuracy, especially if there is chroma noise (rainbow
effect) or any grayscale video. The main purpose of setting mp to a chroma plane is
to reduce CPU load and make pullup usable in realtime on slow machines.
For best results (without duplicated frames in the output file) it is necessary to change
the output frame rate. For example, to inverse telecine NTSC input:
ffmpeg -i input -vf pullup -r 24000/1001 ...
qp
Change video quantization parameters (QP).
The filter accepts the following option:
qp Set expression for quantization parameter.
The expression is evaluated through the eval API and can contain, among others, the
following constants:
known
1 if index is not 129, 0 otherwise.
qp Sequential index starting from -129 to 128.
Examples
• Some equation like:
qp=2+2*sin(PI*qp)
qrencode
Generate a QR code using the libqrencode library (see
<https://fukuchi.org/works/qrencode/>), and overlay it on top of the current frame.
To enable the compilation of this filter, you need to configure FFmpeg with
"--enable-libqrencode".
The QR code is generated from the provided text or text pattern. The corresponding QR code
is scaled and overlayed into the video output according to the specified options.
In case no text is specified, no QR code is overlaied.
This filter accepts the following options:
qrcode_width, q
padded_qrcode_width, Q
Specify an expression for the width of the rendered QR code, with and without padding.
The qrcode_width expression can reference the value set by the padded_qrcode_width
expression, and vice versa. By default padded_qrcode_width is set to qrcode_width,
meaning that there is no padding.
These expressions are evaluated for each new frame.
See the qrencode Expressions section for details.
x
y Specify an expression for positioning the padded QR code top-left corner. The x
expression can reference the value set by the y expression, and vice.
By default x and y are set set to 0, meaning that the QR code is placed in the top
left corner of the input.
These expressions are evaluated for each new frame.
See the qrencode Expressions section for details.
case_sensitive, cs
Instruct libqrencode to use case sensitive encoding. This is enabled by default. This
can be disabled to reduce the QR encoding size.
level, l
Specify the QR encoding error correction level. With an higher correction level, the
encoding size will increase but the code will be more robust to corruption. Lower
level is L.
It accepts the following values:
L
M
Q
H
expansion
Select how the input text is expanded. Can be either "none", or "normal" (default).
See the qrencode Text expansion section below for details.
text
textfile
Define the text to be rendered. In case neither is specified, no QR is encoded (just
an empty colored frame).
In case expansion is enabled, the text is treated as a text template, using the
qrencode expansion mechanism. See the qrencode Text expansion section below for
details.
background_color, bc
foreground_color, fc
Set the QR code and background color. The default value of foreground_color is
"black", the default value of background_color is "white".
For the syntax of the color options, check the "Color" section in the ffmpeg-utils
manual.
qrencode Expressions
The expressions set by the options contain the following constants and functions.
dar input display aspect ratio, it is the same as (w / h) * sar
duration
the current frame's duration, in seconds
hsub
vsub
horizontal and vertical chroma subsample values. For example for the pixel format
"yuv422p" hsub is 2 and vsub is 1.
main_h, H
the input height
main_w, W
the input width
n the number of input frame, starting from 0
pict_type
a number representing the picture type
qr_w, w
the width of the encoded QR code
rendered_qr_w, q
rendered_padded_qr_w, Q
the width of the rendered QR code, without and without padding.
These parameters allow the q and Q expressions to refer to each other, so you can for
example specify "q=3/4*Q".
rand(min, max)
return a random number included between min and max
sar the input sample aspect ratio
t timestamp expressed in seconds, NAN if the input timestamp is unknown
x
y the x and y offset coordinates where the text is drawn.
These parameters allow the x and y expressions to refer to each other, so you can for
example specify "y=x/dar".
qrencode Text expansion
If expansion is set to "none", the text is printed verbatim.
If expansion is set to "normal" (which is the default), the following expansion mechanism
is used.
The backslash character \, followed by any character, always expands to the second
character.
Sequences of the form "%{...}" are expanded. The text between the braces is a function
name, possibly followed by arguments separated by ':'. If the arguments contain special
characters or delimiters (':' or '}'), they should be escaped.
Note that they probably must also be escaped as the value for the text option in the
filter argument string and as the filter argument in the filtergraph description, and
possibly also for the shell, that makes up to four levels of escaping; using a text file
with the textfile option avoids these problems.
The following functions are available:
n, frame_num
return the frame number
pts Return the presentation timestamp of the current frame.
It can take up to two arguments.
The first argument is the format of the timestamp; it defaults to "flt" for seconds as
a decimal number with microsecond accuracy; "hms" stands for a formatted
[-]HH:MM:SS.mmm timestamp with millisecond accuracy. "gmtime" stands for the
timestamp of the frame formatted as UTC time; "localtime" stands for the timestamp of
the frame formatted as local time zone time. If the format is set to "hms24hh", the
time is formatted in 24h format (00-23).
The second argument is an offset added to the timestamp.
If the format is set to "localtime" or "gmtime", a third argument may be supplied: a
"strftime" C function format string. By default, YYYY-MM-DD HH:MM:SS format will be
used.
expr, e
Evaluate the expression's value and output as a double.
It must take one argument specifying the expression to be evaluated, accepting the
constants and functions defined in qrencode_expressions.
expr_formatted, ef
Evaluate the expression's value and output as a formatted string.
The first argument is the expression to be evaluated, just as for the expr function.
The second argument specifies the output format. Allowed values are x, X, d and u.
They are treated exactly as in the "printf" function. The third parameter is optional
and sets the number of positions taken by the output. It can be used to add padding
with zeros from the left.
gmtime
The time at which the filter is running, expressed in UTC. It can accept an argument:
a "strftime" C function format string. The format string is extended to support the
variable %[1-6]N which prints fractions of the second with optionally specified number
of digits.
localtime
The time at which the filter is running, expressed in the local time zone. It can
accept an argument: a "strftime" C function format string. The format string is
extended to support the variable %[1-6]N which prints fractions of the second with
optionally specified number of digits.
metadata
Frame metadata. Takes one or two arguments.
The first argument is mandatory and specifies the metadata key.
The second argument is optional and specifies a default value, used when the metadata
key is not found or empty.
Available metadata can be identified by inspecting entries starting with TAG included
within each frame section printed by running "ffprobe -show_frames".
String metadata generated in filters leading to the qrencode filter are also
available.
rand(min, max)
return a random number included between min and max
Examples
• Generate a QR code encoding the specified text with the default size, overalaid in the
top left corner of the input video, with the default size:
qrencode=text=www.ffmpeg.org
• Same as below, but select blue on pink colors:
qrencode=text=www.ffmpeg.org:bc=pink@0.5:fc=blue
• Place the QR code in the bottom right corner of the input video:
qrencode=text=www.ffmpeg.org:x=W-Q:y=H-Q
• Generate a QR code with width of 200 pixels and padding, making the padded width 4/3
of the QR code width:
qrencode=text=www.ffmpeg.org:q=200:Q=4/3*q
• Generate a QR code with padded width of 200 pixels and padding, making the QR code
width 3/4 of the padded width:
qrencode=text=www.ffmpeg.org:Q=200:q=3/4*Q
• Make the QR code a fraction of the input video width:
qrencode=text=www.ffmpeg.org:q=W/5
• Generate a QR code encoding the frame number:
qrencode=text=%{n}
• Generate a QR code encoding the GMT timestamp:
qrencode=text=%{gmtime}
• Generate a QR code encoding the timestamp expressed as a float:
qrencode=text=%{pts}
quirc
Identify and decode a QR code using the libquirc library (see
<https://github.com/dlbeer/quirc/>), and print the identified QR codes positions and
payload as metadata.
To enable the compilation of this filter, you need to configure FFmpeg with
"--enable-libquirc".
For each found QR code in the input video, some metadata entries are added with the prefix
lavfi.quirc.N, where N is the index, starting from 0, associated to the QR code.
A description of each metadata value follows:
lavfi.quirc.count
the number of found QR codes, it is not set in case none was found
lavfi.quirc.N.corner.M.x
lavfi.quirc.N.coreer.M.y
the x/y positions of the four corners of the square containing the QR code, where M is
the index of the corner starting from 0
lavfi.quirc.N.payload
the payload of the QR code
random
Flush video frames from internal cache of frames into a random order. No frame is
discarded. Inspired by frei0r nervous filter.
frames
Set size in number of frames of internal cache, in range from 2 to 512. Default is 30.
seed
Set seed for random number generator, must be an integer included between 0 and
"UINT32_MAX". If not specified, or if explicitly set to less than 0, the filter will
try to use a good random seed on a best effort basis.
readeia608
Read closed captioning (EIA-608) information from the top lines of a video frame.
This filter adds frame metadata for "lavfi.readeia608.X.cc" and "lavfi.readeia608.X.line",
where "X" is the number of the identified line with EIA-608 data (starting from 0). A
description of each metadata value follows:
lavfi.readeia608.X.cc
The two bytes stored as EIA-608 data (printed in hexadecimal).
lavfi.readeia608.X.line
The number of the line on which the EIA-608 data was identified and read.
This filter accepts the following options:
scan_min
Set the line to start scanning for EIA-608 data. Default is 0.
scan_max
Set the line to end scanning for EIA-608 data. Default is 29.
spw Set the ratio of width reserved for sync code detection. Default is 0.27. Allowed
range is "[0.1 - 0.7]".
chp Enable checking the parity bit. In the event of a parity error, the filter will output
0x00 for that character. Default is false.
lp Lowpass lines prior to further processing. Default is enabled.
Commands
This filter supports the all above options as commands.
Examples
• Output a csv with presentation time and the first two lines of identified EIA-608
captioning data.
ffprobe -f lavfi -i movie=captioned_video.mov,readeia608 -show_entries frame=pts_time:frame_tags=lavfi.readeia608.0.cc,lavfi.readeia608.1.cc -of csv
readvitc
Read vertical interval timecode (VITC) information from the top lines of a video frame.
The filter adds frame metadata key "lavfi.readvitc.tc_str" with the timecode value, if a
valid timecode has been detected. Further metadata key "lavfi.readvitc.found" is set to
0/1 depending on whether timecode data has been found or not.
This filter accepts the following options:
scan_max
Set the maximum number of lines to scan for VITC data. If the value is set to -1 the
full video frame is scanned. Default is 45.
thr_b
Set the luma threshold for black. Accepts float numbers in the range [0.0,1.0],
default value is 0.2. The value must be equal or less than "thr_w".
thr_w
Set the luma threshold for white. Accepts float numbers in the range [0.0,1.0],
default value is 0.6. The value must be equal or greater than "thr_b".
Examples
• Detect and draw VITC data onto the video frame; if no valid VITC is detected, draw
"--:--:--:--" as a placeholder:
ffmpeg -i input.avi -filter:v 'readvitc,drawtext=fontfile=FreeMono.ttf:text=%{metadata\\:lavfi.readvitc.tc_str\\:--\\\\\\:--\\\\\\:--\\\\\\:--}:x=(w-tw)/2:y=400-ascent'
remap
Remap pixels using 2nd: Xmap and 3rd: Ymap input video stream.
Destination pixel at position (X, Y) will be picked from source (x, y) position where x =
Xmap(X, Y) and y = Ymap(X, Y). If mapping values are out of range, zero value for pixel
will be used for destination pixel.
Xmap and Ymap input video streams must be of same dimensions. Output video stream will
have Xmap/Ymap video stream dimensions. Xmap and Ymap input video streams are 16bit
depth, single channel.
format
Specify pixel format of output from this filter. Can be "color" or "gray". Default is
"color".
fill
Specify the color of the unmapped pixels. For the syntax of this option, check the
"Color" section in the ffmpeg-utils manual. Default color is "black".
removegrain
The removegrain filter is a spatial denoiser for progressive video.
m0 Set mode for the first plane.
m1 Set mode for the second plane.
m2 Set mode for the third plane.
m3 Set mode for the fourth plane.
Range of mode is from 0 to 24. Description of each mode follows:
0 Leave input plane unchanged. Default.
1 Clips the pixel with the minimum and maximum of the 8 neighbour pixels.
2 Clips the pixel with the second minimum and maximum of the 8 neighbour pixels.
3 Clips the pixel with the third minimum and maximum of the 8 neighbour pixels.
4 Clips the pixel with the fourth minimum and maximum of the 8 neighbour pixels. This
is equivalent to a median filter.
5 Line-sensitive clipping giving the minimal change.
6 Line-sensitive clipping, intermediate.
7 Line-sensitive clipping, intermediate.
8 Line-sensitive clipping, intermediate.
9 Line-sensitive clipping on a line where the neighbours pixels are the closest.
10 Replaces the target pixel with the closest neighbour.
11 [1 2 1] horizontal and vertical kernel blur.
12 Same as mode 11.
13 Bob mode, interpolates top field from the line where the neighbours pixels are the
closest.
14 Bob mode, interpolates bottom field from the line where the neighbours pixels are the
closest.
15 Bob mode, interpolates top field. Same as 13 but with a more complicated interpolation
formula.
16 Bob mode, interpolates bottom field. Same as 14 but with a more complicated
interpolation formula.
17 Clips the pixel with the minimum and maximum of respectively the maximum and minimum
of each pair of opposite neighbour pixels.
18 Line-sensitive clipping using opposite neighbours whose greatest distance from the
current pixel is minimal.
19 Replaces the pixel with the average of its 8 neighbours.
20 Averages the 9 pixels ([1 1 1] horizontal and vertical blur).
21 Clips pixels using the averages of opposite neighbour.
22 Same as mode 21 but simpler and faster.
23 Small edge and halo removal, but reputed useless.
24 Similar as 23.
removelogo
Suppress a TV station logo, using an image file to determine which pixels comprise the
logo. It works by filling in the pixels that comprise the logo with neighboring pixels.
The filter accepts the following options:
filename, f
Set the filter bitmap file, which can be any image format supported by libavformat.
The width and height of the image file must match those of the video stream being
processed.
Pixels in the provided bitmap image with a value of zero are not considered part of the
logo, non-zero pixels are considered part of the logo. If you use white (255) for the logo
and black (0) for the rest, you will be safe. For making the filter bitmap, it is
recommended to take a screen capture of a black frame with the logo visible, and then
using a threshold filter followed by the erode filter once or twice.
If needed, little splotches can be fixed manually. Remember that if logo pixels are not
covered, the filter quality will be much reduced. Marking too many pixels as part of the
logo does not hurt as much, but it will increase the amount of blurring needed to cover
over the image and will destroy more information than necessary, and extra pixels will
slow things down on a large logo.
repeatfields
This filter uses the repeat_field flag from the Video ES headers and hard repeats fields
based on its value.
reverse
Reverse a video clip.
Warning: This filter requires memory to buffer the entire clip, so trimming is suggested.
Examples
• Take the first 5 seconds of a clip, and reverse it.
trim=end=5,reverse
rgbashift
Shift R/G/B/A pixels horizontally and/or vertically.
The filter accepts the following options:
rh Set amount to shift red horizontally.
rv Set amount to shift red vertically.
gh Set amount to shift green horizontally.
gv Set amount to shift green vertically.
bh Set amount to shift blue horizontally.
bv Set amount to shift blue vertically.
ah Set amount to shift alpha horizontally.
av Set amount to shift alpha vertically.
edge
Set edge mode, can be smear, default, or warp.
Commands
This filter supports the all above options as commands.
roberts
Apply roberts cross operator to input video stream.
The filter accepts the following option:
planes
Set which planes will be processed, unprocessed planes will be copied. By default
value 0xf, all planes will be processed.
scale
Set value which will be multiplied with filtered result.
delta
Set value which will be added to filtered result.
Commands
This filter supports the all above options as commands.
rotate
Rotate video by an arbitrary angle expressed in radians.
The filter accepts the following options:
A description of the optional parameters follows.
angle, a
Set an expression for the angle by which to rotate the input video clockwise,
expressed as a number of radians. A negative value will result in a counter-clockwise
rotation. By default it is set to "0".
This expression is evaluated for each frame.
out_w, ow
Set the output width expression, default value is "iw". This expression is evaluated
just once during configuration.
out_h, oh
Set the output height expression, default value is "ih". This expression is evaluated
just once during configuration.
bilinear
Enable bilinear interpolation if set to 1, a value of 0 disables it. Default value is
1.
fillcolor, c
Set the color used to fill the output area not covered by the rotated image. For the
general syntax of this option, check the "Color" section in the ffmpeg-utils manual.
If the special value "none" is selected then no background is printed (useful for
example if the background is never shown).
Default value is "black".
The expressions for the angle and the output size can contain the following constants and
functions:
n sequential number of the input frame, starting from 0. It is always NAN before the
first frame is filtered.
t time in seconds of the input frame, it is set to 0 when the filter is configured. It
is always NAN before the first frame is filtered.
hsub
vsub
horizontal and vertical chroma subsample values. For example for the pixel format
"yuv422p" hsub is 2 and vsub is 1.
in_w, iw
in_h, ih
the input video width and height
out_w, ow
out_h, oh
the output width and height, that is the size of the padded area as specified by the
width and height expressions
rotw(a)
roth(a)
the minimal width/height required for completely containing the input video rotated by
a radians.
These are only available when computing the out_w and out_h expressions.
Examples
• Rotate the input by PI/6 radians clockwise:
rotate=PI/6
• Rotate the input by PI/6 radians counter-clockwise:
rotate=-PI/6
• Rotate the input by 45 degrees clockwise:
rotate=45*PI/180
• Apply a constant rotation with period T, starting from an angle of PI/3:
rotate=PI/3+2*PI*t/T
• Make the input video rotation oscillating with a period of T seconds and an amplitude
of A radians:
rotate=A*sin(2*PI/T*t)
• Rotate the video, output size is chosen so that the whole rotating input video is
always completely contained in the output:
rotate='2*PI*t:ow=hypot(iw,ih):oh=ow'
• Rotate the video, reduce the output size so that no background is ever shown:
rotate=2*PI*t:ow='min(iw,ih)/sqrt(2)':oh=ow:c=none
Commands
The filter supports the following commands:
a, angle
Set the angle expression. The command accepts the same syntax of the corresponding
option.
If the specified expression is not valid, it is kept at its current value.
sab
Apply Shape Adaptive Blur.
The filter accepts the following options:
luma_radius, lr
Set luma blur filter strength, must be a value in range 0.1-4.0, default value is 1.0.
A greater value will result in a more blurred image, and in slower processing.
luma_pre_filter_radius, lpfr
Set luma pre-filter radius, must be a value in the 0.1-2.0 range, default value is
1.0.
luma_strength, ls
Set luma maximum difference between pixels to still be considered, must be a value in
the 0.1-100.0 range, default value is 1.0.
chroma_radius, cr
Set chroma blur filter strength, must be a value in range -0.9-4.0. A greater value
will result in a more blurred image, and in slower processing.
chroma_pre_filter_radius, cpfr
Set chroma pre-filter radius, must be a value in the -0.9-2.0 range.
chroma_strength, cs
Set chroma maximum difference between pixels to still be considered, must be a value
in the -0.9-100.0 range.
Each chroma option value, if not explicitly specified, is set to the corresponding luma
option value.
scale
Scale (resize) the input video, using the libswscale library.
The scale filter forces the output display aspect ratio to be the same of the input, by
changing the output sample aspect ratio.
If the input image format is different from the format requested by the next filter, the
scale filter will convert the input to the requested format.
Options
The filter accepts the following options, any of the options supported by the libswscale
scaler, as well as any of the framesync options.
See the ffmpeg-scaler manual for the complete list of scaler options.
width, w
height, h
Set the output video dimension expression. Default value is the input dimension.
If the width or w value is 0, the input width is used for the output. If the height or
h value is 0, the input height is used for the output.
If one and only one of the values is -n with n >= 1, the scale filter will use a value
that maintains the aspect ratio of the input image, calculated from the other
specified dimension. After that it will, however, make sure that the calculated
dimension is divisible by n and adjust the value if necessary.
If both values are -n with n >= 1, the behavior will be identical to both values being
set to 0 as previously detailed.
See below for the list of accepted constants for use in the dimension expression.
eval
Specify when to evaluate width and height expression. It accepts the following values:
init
Only evaluate expressions once during the filter initialization or when a command
is processed.
frame
Evaluate expressions for each incoming frame.
Default value is init.
interl
Set the interlacing mode. It accepts the following values:
1 Force interlaced aware scaling.
0 Do not apply interlaced scaling.
-1 Select interlaced aware scaling depending on whether the source frames are flagged
as interlaced or not.
Default value is 0.
flags
Set libswscale scaling flags. See the ffmpeg-scaler manual for the complete list of
values. If not explicitly specified the filter applies the default flags.
param0, param1
Set libswscale input parameters for scaling algorithms that need them. See the ffmpeg-
scaler manual for the complete documentation. If not explicitly specified the filter
applies empty parameters.
size, s
Set the video size. For the syntax of this option, check the "Video size" section in
the ffmpeg-utils manual.
in_color_matrix
out_color_matrix
Set in/output YCbCr color space type.
This allows the autodetected value to be overridden as well as allows forcing a
specific value used for the output and encoder.
If not specified, the color space type depends on the pixel format.
Possible values:
auto
Choose automatically.
bt709
Format conforming to International Telecommunication Union (ITU) Recommendation
BT.709.
fcc Set color space conforming to the United States Federal Communications Commission
(FCC) Code of Federal Regulations (CFR) Title 47 (2003) 73.682 (a).
bt601
bt470
smpte170m
Set color space conforming to:
• ITU Radiocommunication Sector (ITU-R) Recommendation BT.601
• ITU-R Rec. BT.470-6 (1998) Systems B, B1, and G
• Society of Motion Picture and Television Engineers (SMPTE) ST 170:2004
smpte240m
Set color space conforming to SMPTE ST 240:1999.
bt2020
Set color space conforming to ITU-R BT.2020 non-constant luminance system.
in_range
out_range
Set in/output YCbCr sample range.
This allows the autodetected value to be overridden as well as allows forcing a
specific value used for the output and encoder. If not specified, the range depends on
the pixel format. Possible values:
auto/unknown
Choose automatically.
jpeg/full/pc
Set full range (0-255 in case of 8-bit luma).
mpeg/limited/tv
Set "MPEG" range (16-235 in case of 8-bit luma).
in_chroma_loc
out_chroma_loc
Set in/output chroma sample location. If not specified, center-sited chroma is used by
default. Possible values:
auto, unknown
left
center
topleft
top
bottomleft
bottom
force_original_aspect_ratio
Enable decreasing or increasing output video width or height if necessary to keep the
original aspect ratio. Possible values:
disable
Scale the video as specified and disable this feature.
decrease
The output video dimensions will automatically be decreased if needed.
increase
The output video dimensions will automatically be increased if needed.
One useful instance of this option is that when you know a specific device's maximum
allowed resolution, you can use this to limit the output video to that, while
retaining the aspect ratio. For example, device A allows 1280x720 playback, and your
video is 1920x800. Using this option (set it to decrease) and specifying 1280x720 to
the command line makes the output 1280x533.
Please note that this is a different thing than specifying -1 for w or h, you still
need to specify the output resolution for this option to work.
force_divisible_by
Ensures that both the output dimensions, width and height, are divisible by the given
integer when used together with force_original_aspect_ratio. This works similar to
using "-n" in the w and h options.
This option respects the value set for force_original_aspect_ratio, increasing or
decreasing the resolution accordingly. The video's aspect ratio may be slightly
modified.
This option can be handy if you need to have a video fit within or exceed a defined
resolution using force_original_aspect_ratio but also have encoder restrictions on
width or height divisibility.
The values of the w and h options are expressions containing the following constants:
in_w
in_h
The input width and height
iw
ih These are the same as in_w and in_h.
out_w
out_h
The output (scaled) width and height
ow
oh These are the same as out_w and out_h
a The same as iw / ih
sar input sample aspect ratio
dar The input display aspect ratio. Calculated from "(iw / ih) * sar".
hsub
vsub
horizontal and vertical input chroma subsample values. For example for the pixel
format "yuv422p" hsub is 2 and vsub is 1.
ohsub
ovsub
horizontal and vertical output chroma subsample values. For example for the pixel
format "yuv422p" hsub is 2 and vsub is 1.
n The (sequential) number of the input frame, starting from 0. Only available with
"eval=frame".
t The presentation timestamp of the input frame, expressed as a number of seconds. Only
available with "eval=frame".
pos The position (byte offset) of the frame in the input stream, or NaN if this
information is unavailable and/or meaningless (for example in case of synthetic
video). Only available with "eval=frame". Deprecated, do not use.
ref_w, rw
ref_h, rh
ref_a
ref_dar, rdar
ref_n
ref_t
ref_pos
Eqvuialent to the above, but for a second reference input. If any of these variables
are present, this filter accepts two inputs.
Examples
• Scale the input video to a size of 200x100
scale=w=200:h=100
This is equivalent to:
scale=200:100
or:
scale=200x100
• Specify a size abbreviation for the output size:
scale=qcif
which can also be written as:
scale=size=qcif
• Scale the input to 2x:
scale=w=2*iw:h=2*ih
• The above is the same as:
scale=2*in_w:2*in_h
• Scale the input to 2x with forced interlaced scaling:
scale=2*iw:2*ih:interl=1
• Scale the input to half size:
scale=w=iw/2:h=ih/2
• Increase the width, and set the height to the same size:
scale=3/2*iw:ow
• Seek Greek harmony:
scale=iw:1/PHI*iw
scale=ih*PHI:ih
• Increase the height, and set the width to 3/2 of the height:
scale=w=3/2*oh:h=3/5*ih
• Increase the size, making the size a multiple of the chroma subsample values:
scale="trunc(3/2*iw/hsub)*hsub:trunc(3/2*ih/vsub)*vsub"
• Increase the width to a maximum of 500 pixels, keeping the same aspect ratio as the
input:
scale=w='min(500\, iw*3/2):h=-1'
• Make pixels square by combining scale and setsar:
scale='trunc(ih*dar):ih',setsar=1/1
• Make pixels square by combining scale and setsar, making sure the resulting resolution
is even (required by some codecs):
scale='trunc(ih*dar/2)*2:trunc(ih/2)*2',setsar=1/1
• Scale a subtitle stream (sub) to match the main video (main) in size before
overlaying. ("scale2ref")
'[main]split[a][b]; [ref][a]scale=rw:rh[c]; [b][c]overlay'
• Scale a logo to 1/10th the height of a video, while preserving its display aspect
ratio.
[logo-in][video-in]scale=w=oh*dar:h=rh/10[logo-out]
Commands
This filter supports the following commands:
width, w
height, h
Set the output video dimension expression. The command accepts the same syntax of the
corresponding option.
If the specified expression is not valid, it is kept at its current value.
scale_cuda
Scale (resize) and convert (pixel format) the input video, using accelerated CUDA kernels.
Setting the output width and height works in the same way as for the scale filter.
The filter accepts the following options:
w
h Set the output video dimension expression. Default value is the input dimension.
Allows for the same expressions as the scale filter.
interp_algo
Sets the algorithm used for scaling:
nearest
Nearest neighbour
Used by default if input parameters match the desired output.
bilinear
Bilinear
bicubic
Bicubic
This is the default.
lanczos
Lanczos
format
Controls the output pixel format. By default, or if none is specified, the input pixel
format is used.
The filter does not support converting between YUV and RGB pixel formats.
passthrough
If set to 0, every frame is processed, even if no conversion is necessary. This mode
can be useful to use the filter as a buffer for a downstream frame-consumer that
exhausts the limited decoder frame pool.
If set to 1, frames are passed through as-is if they match the desired output
parameters. This is the default behaviour.
param
Algorithm-Specific parameter.
Affects the curves of the bicubic algorithm.
force_original_aspect_ratio
force_divisible_by
Work the same as the identical scale filter options.
Examples
• Scale input to 720p, keeping aspect ratio and ensuring the output is yuv420p.
scale_cuda=-2:720:format=yuv420p
• Upscale to 4K using nearest neighbour algorithm.
scale_cuda=4096:2160:interp_algo=nearest
• Don't do any conversion or scaling, but copy all input frames into newly allocated
ones. This can be useful to deal with a filter and encode chain that otherwise
exhausts the decoders frame pool.
scale_cuda=passthrough=0
scale_npp
Use the NVIDIA Performance Primitives (libnpp) to perform scaling and/or pixel format
conversion on CUDA video frames. Setting the output width and height works in the same way
as for the scale filter.
The following additional options are accepted:
format
The pixel format of the output CUDA frames. If set to the string "same" (the default),
the input format will be kept. Note that automatic format negotiation and conversion
is not yet supported for hardware frames
interp_algo
The interpolation algorithm used for resizing. One of the following:
nn Nearest neighbour.
linear
cubic
cubic2p_bspline
2-parameter cubic (B=1, C=0)
cubic2p_catmullrom
2-parameter cubic (B=0, C=1/2)
cubic2p_b05c03
2-parameter cubic (B=1/2, C=3/10)
super
Supersampling
lanczos
force_original_aspect_ratio
Enable decreasing or increasing output video width or height if necessary to keep the
original aspect ratio. Possible values:
disable
Scale the video as specified and disable this feature.
decrease
The output video dimensions will automatically be decreased if needed.
increase
The output video dimensions will automatically be increased if needed.
One useful instance of this option is that when you know a specific device's maximum
allowed resolution, you can use this to limit the output video to that, while
retaining the aspect ratio. For example, device A allows 1280x720 playback, and your
video is 1920x800. Using this option (set it to decrease) and specifying 1280x720 to
the command line makes the output 1280x533.
Please note that this is a different thing than specifying -1 for w or h, you still
need to specify the output resolution for this option to work.
force_divisible_by
Ensures that both the output dimensions, width and height, are divisible by the given
integer when used together with force_original_aspect_ratio. This works similar to
using "-n" in the w and h options.
This option respects the value set for force_original_aspect_ratio, increasing or
decreasing the resolution accordingly. The video's aspect ratio may be slightly
modified.
This option can be handy if you need to have a video fit within or exceed a defined
resolution using force_original_aspect_ratio but also have encoder restrictions on
width or height divisibility.
eval
Specify when to evaluate width and height expression. It accepts the following values:
init
Only evaluate expressions once during the filter initialization or when a command
is processed.
frame
Evaluate expressions for each incoming frame.
The values of the w and h options are expressions containing the following constants:
in_w
in_h
The input width and height
iw
ih These are the same as in_w and in_h.
out_w
out_h
The output (scaled) width and height
ow
oh These are the same as out_w and out_h
a The same as iw / ih
sar input sample aspect ratio
dar The input display aspect ratio. Calculated from "(iw / ih) * sar".
n The (sequential) number of the input frame, starting from 0. Only available with
"eval=frame".
t The presentation timestamp of the input frame, expressed as a number of seconds. Only
available with "eval=frame".
pos The position (byte offset) of the frame in the input stream, or NaN if this
information is unavailable and/or meaningless (for example in case of synthetic
video). Only available with "eval=frame". Deprecated, do not use.
scale2ref_npp
Use the NVIDIA Performance Primitives (libnpp) to scale (resize) the input video, based on
a reference video.
See the scale_npp filter for available options, scale2ref_npp supports the same but uses
the reference video instead of the main input as basis. scale2ref_npp also supports the
following additional constants for the w and h options:
main_w
main_h
The main input video's width and height
main_a
The same as main_w / main_h
main_sar
The main input video's sample aspect ratio
main_dar, mdar
The main input video's display aspect ratio. Calculated from "(main_w / main_h) *
main_sar".
main_n
The (sequential) number of the main input frame, starting from 0. Only available with
"eval=frame".
main_t
The presentation timestamp of the main input frame, expressed as a number of seconds.
Only available with "eval=frame".
main_pos
The position (byte offset) of the frame in the main input stream, or NaN if this
information is unavailable and/or meaningless (for example in case of synthetic
video). Only available with "eval=frame".
Examples
• Scale a subtitle stream (b) to match the main video (a) in size before overlaying
'scale2ref_npp[b][a];[a][b]overlay_cuda'
• Scale a logo to 1/10th the height of a video, while preserving its display aspect
ratio.
[logo-in][video-in]scale2ref_npp=w=oh*mdar:h=ih/10[logo-out][video-out]
scale_vt
Scale and convert the color parameters using VTPixelTransferSession.
The filter accepts the following options:
w
h Set the output video dimension expression. Default value is the input dimension.
color_matrix
Set the output colorspace matrix.
color_primaries
Set the output color primaries.
color_transfer
Set the output transfer characteristics.
scharr
Apply scharr operator to input video stream.
The filter accepts the following option:
planes
Set which planes will be processed, unprocessed planes will be copied. By default
value 0xf, all planes will be processed.
scale
Set value which will be multiplied with filtered result.
delta
Set value which will be added to filtered result.
Commands
This filter supports the all above options as commands.
scroll
Scroll input video horizontally and/or vertically by constant speed.
The filter accepts the following options:
horizontal, h
Set the horizontal scrolling speed. Default is 0. Allowed range is from -1 to 1.
Negative values changes scrolling direction.
vertical, v
Set the vertical scrolling speed. Default is 0. Allowed range is from -1 to 1.
Negative values changes scrolling direction.
hpos
Set the initial horizontal scrolling position. Default is 0. Allowed range is from 0
to 1.
vpos
Set the initial vertical scrolling position. Default is 0. Allowed range is from 0 to
1.
Commands
This filter supports the following commands:
horizontal, h
Set the horizontal scrolling speed.
vertical, v
Set the vertical scrolling speed.
scdet
Detect video scene change.
This filter sets frame metadata with mafd between frame, the scene score, and forward the
frame to the next filter, so they can use these metadata to detect scene change or others.
In addition, this filter logs a message and sets frame metadata when it detects a scene
change by threshold.
"lavfi.scd.mafd" metadata keys are set with mafd for every frame.
"lavfi.scd.score" metadata keys are set with scene change score for every frame to detect
scene change.
"lavfi.scd.time" metadata keys are set with current filtered frame time which detect scene
change with threshold.
The filter accepts the following options:
threshold, t
Set the scene change detection threshold as a percentage of maximum change. Good
values are in the "[8.0, 14.0]" range. The range for threshold is "[0., 100.]".
Default value is 10..
sc_pass, s
Set the flag to pass scene change frames to the next filter. Default value is 0 You
can enable it if you want to get snapshot of scene change frames only.
selectivecolor
Adjust cyan, magenta, yellow and black (CMYK) to certain ranges of colors (such as "reds",
"yellows", "greens", "cyans", ...). The adjustment range is defined by the "purity" of the
color (that is, how saturated it already is).
This filter is similar to the Adobe Photoshop Selective Color tool.
The filter accepts the following options:
correction_method
Select color correction method.
Available values are:
absolute
Specified adjustments are applied "as-is" (added/subtracted to original pixel
component value).
relative
Specified adjustments are relative to the original component value.
Default is "absolute".
reds
Adjustments for red pixels (pixels where the red component is the maximum)
yellows
Adjustments for yellow pixels (pixels where the blue component is the minimum)
greens
Adjustments for green pixels (pixels where the green component is the maximum)
cyans
Adjustments for cyan pixels (pixels where the red component is the minimum)
blues
Adjustments for blue pixels (pixels where the blue component is the maximum)
magentas
Adjustments for magenta pixels (pixels where the green component is the minimum)
whites
Adjustments for white pixels (pixels where all components are greater than 128)
neutrals
Adjustments for all pixels except pure black and pure white
blacks
Adjustments for black pixels (pixels where all components are lesser than 128)
psfile
Specify a Photoshop selective color file (".asv") to import the settings from.
All the adjustment settings (reds, yellows, ...) accept up to 4 space separated floating
point adjustment values in the [-1,1] range, respectively to adjust the amount of cyan,
magenta, yellow and black for the pixels of its range.
Examples
• Increase cyan by 50% and reduce yellow by 33% in every green areas, and increase
magenta by 27% in blue areas:
selectivecolor=greens=.5 0 -.33 0:blues=0 .27
• Use a Photoshop selective color preset:
selectivecolor=psfile=MySelectiveColorPresets/Misty.asv
separatefields
The "separatefields" takes a frame-based video input and splits each frame into its
components fields, producing a new half height clip with twice the frame rate and twice
the frame count.
This filter use field-dominance information in frame to decide which of each pair of
fields to place first in the output. If it gets it wrong use setfield filter before
"separatefields" filter.
setdar, setsar
The "setdar" filter sets the Display Aspect Ratio for the filter output video.
This is done by changing the specified Sample (aka Pixel) Aspect Ratio, according to the
following equation:
<DAR> = <HORIZONTAL_RESOLUTION> / <VERTICAL_RESOLUTION> * <SAR>
Keep in mind that the "setdar" filter does not modify the pixel dimensions of the video
frame. Also, the display aspect ratio set by this filter may be changed by later filters
in the filterchain, e.g. in case of scaling or if another "setdar" or a "setsar" filter is
applied.
The "setsar" filter sets the Sample (aka Pixel) Aspect Ratio for the filter output video.
Note that as a consequence of the application of this filter, the output display aspect
ratio will change according to the equation above.
Keep in mind that the sample aspect ratio set by the "setsar" filter may be changed by
later filters in the filterchain, e.g. if another "setsar" or a "setdar" filter is
applied.
It accepts the following parameters:
r, ratio, dar ("setdar" only), sar ("setsar" only)
Set the aspect ratio used by the filter.
The parameter can be a floating point number string, or an expression. If the
parameter is not specified, the value "0" is assumed, meaning that the same input
value is used.
max Set the maximum integer value to use for expressing numerator and denominator when
reducing the expressed aspect ratio to a rational. Default value is 100.
The parameter sar is an expression containing the following constants:
w, h
The input width and height.
a Same as w / h.
sar The input sample aspect ratio.
dar The input display aspect ratio. It is the same as (w / h) * sar.
hsub, vsub
Horizontal and vertical chroma subsample values. For example, for the pixel format
"yuv422p" hsub is 2 and vsub is 1.
Examples
• To change the display aspect ratio to 16:9, specify one of the following:
setdar=dar=1.77777
setdar=dar=16/9
• To change the sample aspect ratio to 10:11, specify:
setsar=sar=10/11
• To set a display aspect ratio of 16:9, and specify a maximum integer value of 1000 in
the aspect ratio reduction, use the command:
setdar=ratio=16/9:max=1000
setfield
Force field for the output video frame.
The "setfield" filter marks the interlace type field for the output frames. It does not
change the input frame, but only sets the corresponding property, which affects how the
frame is treated by following filters (e.g. "fieldorder" or "yadif").
The filter accepts the following options:
mode
Available values are:
auto
Keep the same field property.
bff Mark the frame as bottom-field-first.
tff Mark the frame as top-field-first.
prog
Mark the frame as progressive.
setparams
Force frame parameter for the output video frame.
The "setparams" filter marks interlace and color range for the output frames. It does not
change the input frame, but only sets the corresponding property, which affects how the
frame is treated by filters/encoders.
field_mode
Available values are:
auto
Keep the same field property (default).
bff Mark the frame as bottom-field-first.
tff Mark the frame as top-field-first.
prog
Mark the frame as progressive.
range
Available values are:
auto
Keep the same color range property (default).
unspecified, unknown
Mark the frame as unspecified color range.
limited, tv, mpeg
Mark the frame as limited range.
full, pc, jpeg
Mark the frame as full range.
color_primaries
Set the color primaries. Available values are:
auto
Keep the same color primaries property (default).
bt709
unknown
bt470m
bt470bg
smpte170m
smpte240m
film
bt2020
smpte428
smpte431
smpte432
jedec-p22
color_trc
Set the color transfer. Available values are:
auto
Keep the same color trc property (default).
bt709
unknown
bt470m
bt470bg
smpte170m
smpte240m
linear
log100
log316
iec61966-2-4
bt1361e
iec61966-2-1
bt2020-10
bt2020-12
smpte2084
smpte428
arib-std-b67
colorspace
Set the colorspace. Available values are:
auto
Keep the same colorspace property (default).
gbr
bt709
unknown
fcc
bt470bg
smpte170m
smpte240m
ycgco
bt2020nc
bt2020c
smpte2085
chroma-derived-nc
chroma-derived-c
ictcp
chroma_location
Set the chroma sample location. Available values are:
auto
Keep the same chroma location (default).
unspecified, unknown
left
center
topleft
top
bottomleft
bottom
sharpen_npp
Use the NVIDIA Performance Primitives (libnpp) to perform image sharpening with border
control.
The following additional options are accepted:
border_type
Type of sampling to be used ad frame borders. One of the following:
replicate
Replicate pixel values.
shear
Apply shear transform to input video.
This filter supports the following options:
shx Shear factor in X-direction. Default value is 0. Allowed range is from -2 to 2.
shy Shear factor in Y-direction. Default value is 0. Allowed range is from -2 to 2.
fillcolor, c
Set the color used to fill the output area not covered by the transformed video. For
the general syntax of this option, check the "Color" section in the ffmpeg-utils
manual. If the special value "none" is selected then no background is printed (useful
for example if the background is never shown).
Default value is "black".
interp
Set interpolation type. Can be "bilinear" or "nearest". Default is "bilinear".
Commands
This filter supports the all above options as commands.
showinfo
Show a line containing various information for each input video frame. The input video is
not modified.
This filter supports the following options:
checksum
Calculate checksums of each plane. By default enabled.
udu_sei_as_ascii
Try to print user data unregistered SEI as ascii character when possible, in hex
format otherwise.
The shown line contains a sequence of key/value pairs of the form key:value.
The following values are shown in the output:
n The (sequential) number of the input frame, starting from 0.
pts The Presentation TimeStamp of the input frame, expressed as a number of time base
units. The time base unit depends on the filter input pad.
pts_time
The Presentation TimeStamp of the input frame, expressed as a number of seconds.
fmt The pixel format name.
sar The sample aspect ratio of the input frame, expressed in the form num/den.
s The size of the input frame. For the syntax of this option, check the "Video size"
section in the ffmpeg-utils manual.
i The type of interlaced mode ("P" for "progressive", "T" for top field first, "B" for
bottom field first).
iskey
This is 1 if the frame is a key frame, 0 otherwise.
type
The picture type of the input frame ("I" for an I-frame, "P" for a P-frame, "B" for a
B-frame, or "?" for an unknown type). Also refer to the documentation of the
"AVPictureType" enum and of the "av_get_picture_type_char" function defined in
libavutil/avutil.h.
checksum
The Adler-32 checksum (printed in hexadecimal) of all the planes of the input frame.
plane_checksum
The Adler-32 checksum (printed in hexadecimal) of each plane of the input frame,
expressed in the form "[c0 c1 c2 c3]".
mean
The mean value of pixels in each plane of the input frame, expressed in the form
"[mean0 mean1 mean2 mean3]".
stdev
The standard deviation of pixel values in each plane of the input frame, expressed in
the form "[stdev0 stdev1 stdev2 stdev3]".
showpalette
Displays the 256 colors palette of each frame. This filter is only relevant for pal8 pixel
format frames.
It accepts the following option:
s Set the size of the box used to represent one palette color entry. Default is 30 (for
a "30x30" pixel box).
shuffleframes
Reorder and/or duplicate and/or drop video frames.
It accepts the following parameters:
mapping
Set the destination indexes of input frames. This is space or '|' separated list of
indexes that maps input frames to output frames. Number of indexes also sets maximal
value that each index may have. '-1' index have special meaning and that is to drop
frame.
The first frame has the index 0. The default is to keep the input unchanged.
Examples
• Swap second and third frame of every three frames of the input:
ffmpeg -i INPUT -vf "shuffleframes=0 2 1" OUTPUT
• Swap 10th and 1st frame of every ten frames of the input:
ffmpeg -i INPUT -vf "shuffleframes=9 1 2 3 4 5 6 7 8 0" OUTPUT
shufflepixels
Reorder pixels in video frames.
This filter accepts the following options:
direction, d
Set shuffle direction. Can be forward or inverse direction. Default direction is
forward.
mode, m
Set shuffle mode. Can be horizontal, vertical or block mode.
width, w
height, h
Set shuffle block_size. In case of horizontal shuffle mode only width part of size is
used, and in case of vertical shuffle mode only height part of size is used.
seed, s
Set random seed used with shuffling pixels. Mainly useful to set to be able to reverse
filtering process to get original input. For example, to reverse forward shuffle you
need to use same parameters and exact same seed and to set direction to inverse.
shuffleplanes
Reorder and/or duplicate video planes.
It accepts the following parameters:
map0
The index of the input plane to be used as the first output plane.
map1
The index of the input plane to be used as the second output plane.
map2
The index of the input plane to be used as the third output plane.
map3
The index of the input plane to be used as the fourth output plane.
The first plane has the index 0. The default is to keep the input unchanged.
Examples
• Swap the second and third planes of the input:
ffmpeg -i INPUT -vf shuffleplanes=0:2:1:3 OUTPUT
signalstats
Evaluate various visual metrics that assist in determining issues associated with the
digitization of analog video media.
By default the filter will log these metadata values:
YMIN
Display the minimal Y value contained within the input frame. Expressed in range of
[0-255].
YLOW
Display the Y value at the 10% percentile within the input frame. Expressed in range
of [0-255].
YAVG
Display the average Y value within the input frame. Expressed in range of [0-255].
YHIGH
Display the Y value at the 90% percentile within the input frame. Expressed in range
of [0-255].
YMAX
Display the maximum Y value contained within the input frame. Expressed in range of
[0-255].
UMIN
Display the minimal U value contained within the input frame. Expressed in range of
[0-255].
ULOW
Display the U value at the 10% percentile within the input frame. Expressed in range
of [0-255].
UAVG
Display the average U value within the input frame. Expressed in range of [0-255].
UHIGH
Display the U value at the 90% percentile within the input frame. Expressed in range
of [0-255].
UMAX
Display the maximum U value contained within the input frame. Expressed in range of
[0-255].
VMIN
Display the minimal V value contained within the input frame. Expressed in range of
[0-255].
VLOW
Display the V value at the 10% percentile within the input frame. Expressed in range
of [0-255].
VAVG
Display the average V value within the input frame. Expressed in range of [0-255].
VHIGH
Display the V value at the 90% percentile within the input frame. Expressed in range
of [0-255].
VMAX
Display the maximum V value contained within the input frame. Expressed in range of
[0-255].
SATMIN
Display the minimal saturation value contained within the input frame. Expressed in
range of [0-~181.02].
SATLOW
Display the saturation value at the 10% percentile within the input frame. Expressed
in range of [0-~181.02].
SATAVG
Display the average saturation value within the input frame. Expressed in range of
[0-~181.02].
SATHIGH
Display the saturation value at the 90% percentile within the input frame. Expressed
in range of [0-~181.02].
SATMAX
Display the maximum saturation value contained within the input frame. Expressed in
range of [0-~181.02].
HUEMED
Display the median value for hue within the input frame. Expressed in range of
[0-360].
HUEAVG
Display the average value for hue within the input frame. Expressed in range of
[0-360].
YDIF
Display the average of sample value difference between all values of the Y plane in
the current frame and corresponding values of the previous input frame. Expressed in
range of [0-255].
UDIF
Display the average of sample value difference between all values of the U plane in
the current frame and corresponding values of the previous input frame. Expressed in
range of [0-255].
VDIF
Display the average of sample value difference between all values of the V plane in
the current frame and corresponding values of the previous input frame. Expressed in
range of [0-255].
YBITDEPTH
Display bit depth of Y plane in current frame. Expressed in range of [0-16].
UBITDEPTH
Display bit depth of U plane in current frame. Expressed in range of [0-16].
VBITDEPTH
Display bit depth of V plane in current frame. Expressed in range of [0-16].
The filter accepts the following options:
stat
out stat specify an additional form of image analysis. out output video with the
specified type of pixel highlighted.
Both options accept the following values:
tout
Identify temporal outliers pixels. A temporal outlier is a pixel unlike the
neighboring pixels of the same field. Examples of temporal outliers include the
results of video dropouts, head clogs, or tape tracking issues.
vrep
Identify vertical line repetition. Vertical line repetition includes similar rows
of pixels within a frame. In born-digital video vertical line repetition is
common, but this pattern is uncommon in video digitized from an analog source.
When it occurs in video that results from the digitization of an analog source it
can indicate concealment from a dropout compensator.
brng
Identify pixels that fall outside of legal broadcast range.
color, c
Set the highlight color for the out option. The default color is yellow.
Examples
• Output data of various video metrics:
ffprobe -f lavfi movie=example.mov,signalstats="stat=tout+vrep+brng" -show_frames
• Output specific data about the minimum and maximum values of the Y plane per frame:
ffprobe -f lavfi movie=example.mov,signalstats -show_entries frame_tags=lavfi.signalstats.YMAX,lavfi.signalstats.YMIN
• Playback video while highlighting pixels that are outside of broadcast range in red.
ffplay example.mov -vf signalstats="out=brng:color=red"
• Playback video with signalstats metadata drawn over the frame.
ffplay example.mov -vf signalstats=stat=brng+vrep+tout,drawtext=fontfile=FreeSerif.ttf:textfile=signalstat_drawtext.txt
The contents of signalstat_drawtext.txt used in the command are:
time %{pts:hms}
Y (%{metadata:lavfi.signalstats.YMIN}-%{metadata:lavfi.signalstats.YMAX})
U (%{metadata:lavfi.signalstats.UMIN}-%{metadata:lavfi.signalstats.UMAX})
V (%{metadata:lavfi.signalstats.VMIN}-%{metadata:lavfi.signalstats.VMAX})
saturation maximum: %{metadata:lavfi.signalstats.SATMAX}
signature
Calculates the MPEG-7 Video Signature. The filter can handle more than one input. In this
case the matching between the inputs can be calculated additionally. The filter always
passes through the first input. The signature of each stream can be written into a file.
It accepts the following options:
detectmode
Enable or disable the matching process.
Available values are:
off Disable the calculation of a matching (default).
full
Calculate the matching for the whole video and output whether the whole video
matches or only parts.
fast
Calculate only until a matching is found or the video ends. Should be faster in
some cases.
nb_inputs
Set the number of inputs. The option value must be a non negative integer. Default
value is 1.
filename
Set the path to which the output is written. If there is more than one input, the path
must be a prototype, i.e. must contain %d or %0nd (where n is a positive integer),
that will be replaced with the input number. If no filename is specified, no output
will be written. This is the default.
format
Choose the output format.
Available values are:
binary
Use the specified binary representation (default).
xml Use the specified xml representation.
th_d
Set threshold to detect one word as similar. The option value must be an integer
greater than zero. The default value is 9000.
th_dc
Set threshold to detect all words as similar. The option value must be an integer
greater than zero. The default value is 60000.
th_xh
Set threshold to detect frames as similar. The option value must be an integer greater
than zero. The default value is 116.
th_di
Set the minimum length of a sequence in frames to recognize it as matching sequence.
The option value must be a non negative integer value. The default value is 0.
th_it
Set the minimum relation, that matching frames to all frames must have. The option
value must be a double value between 0 and 1. The default value is 0.5.
Examples
• To calculate the signature of an input video and store it in signature.bin:
ffmpeg -i input.mkv -vf signature=filename=signature.bin -map 0:v -f null -
• To detect whether two videos match and store the signatures in XML format in
signature0.xml and signature1.xml:
ffmpeg -i input1.mkv -i input2.mkv -filter_complex "[0:v][1:v] signature=nb_inputs=2:detectmode=full:format=xml:filename=signature%d.xml" -map :v -f null -
siti
Calculate Spatial Information (SI) and Temporal Information (TI) scores for a video, as
defined in ITU-T Rec. P.910 (11/21): Subjective video quality assessment methods for
multimedia applications. Available PDF at
<https://www.itu.int/rec/T-REC-P.910-202111-S/en>. Note that this is a legacy
implementation that corresponds to a superseded recommendation. Refer to ITU-T Rec. P.910
(07/22) for the latest version: <https://www.itu.int/rec/T-REC-P.910-202207-I/en>
It accepts the following option:
print_summary
If set to 1, Summary statistics will be printed to the console. Default 0.
Examples
• To calculate SI/TI metrics and print summary:
ffmpeg -i input.mp4 -vf siti=print_summary=1 -f null -
smartblur
Blur the input video without impacting the outlines.
It accepts the following options:
luma_radius, lr
Set the luma radius. The option value must be a float number in the range [0.1,5.0]
that specifies the variance of the gaussian filter used to blur the image (slower if
larger). Default value is 1.0.
luma_strength, ls
Set the luma strength. The option value must be a float number in the range [-1.0,1.0]
that configures the blurring. A value included in [0.0,1.0] will blur the image
whereas a value included in [-1.0,0.0] will sharpen the image. Default value is 1.0.
luma_threshold, lt
Set the luma threshold used as a coefficient to determine whether a pixel should be
blurred or not. The option value must be an integer in the range [-30,30]. A value of
0 will filter all the image, a value included in [0,30] will filter flat areas and a
value included in [-30,0] will filter edges. Default value is 0.
chroma_radius, cr
Set the chroma radius. The option value must be a float number in the range [0.1,5.0]
that specifies the variance of the gaussian filter used to blur the image (slower if
larger). Default value is luma_radius.
chroma_strength, cs
Set the chroma strength. The option value must be a float number in the range
[-1.0,1.0] that configures the blurring. A value included in [0.0,1.0] will blur the
image whereas a value included in [-1.0,0.0] will sharpen the image. Default value is
luma_strength.
chroma_threshold, ct
Set the chroma threshold used as a coefficient to determine whether a pixel should be
blurred or not. The option value must be an integer in the range [-30,30]. A value of
0 will filter all the image, a value included in [0,30] will filter flat areas and a
value included in [-30,0] will filter edges. Default value is luma_threshold.
alpha_radius, ar
Set the alpha radius. The option value must be a float number in the range [0.1,5.0]
that specifies the variance of the gaussian filter used to blur the image (slower if
larger). Default value is luma_radius.
alpha_strength, as
Set the alpha strength. The option value must be a float number in the range
[-1.0,1.0] that configures the blurring. A value included in [0.0,1.0] will blur the
image whereas a value included in [-1.0,0.0] will sharpen the image. Default value is
luma_strength.
alpha_threshold, at
Set the alpha threshold used as a coefficient to determine whether a pixel should be
blurred or not. The option value must be an integer in the range [-30,30]. A value of
0 will filter all the image, a value included in [0,30] will filter flat areas and a
value included in [-30,0] will filter edges. Default value is luma_threshold.
If a chroma or alpha option is not explicitly set, the corresponding luma value is set.
sobel
Apply sobel operator to input video stream.
The filter accepts the following option:
planes
Set which planes will be processed, unprocessed planes will be copied. By default
value 0xf, all planes will be processed.
scale
Set value which will be multiplied with filtered result.
delta
Set value which will be added to filtered result.
Commands
This filter supports the all above options as commands.
spp
Apply a simple postprocessing filter that compresses and decompresses the image at several
(or - in the case of quality level 6 - all) shifts and average the results.
The filter accepts the following options:
quality
Set quality. This option defines the number of levels for averaging. It accepts an
integer in the range 0-6. If set to 0, the filter will have no effect. A value of 6
means the higher quality. For each increment of that value the speed drops by a factor
of approximately 2. Default value is 3.
qp Force a constant quantization parameter. If not set, the filter will use the QP from
the video stream (if available).
mode
Set thresholding mode. Available modes are:
hard
Set hard thresholding (default).
soft
Set soft thresholding (better de-ringing effect, but likely blurrier).
use_bframe_qp
Enable the use of the QP from the B-Frames if set to 1. Using this option may cause
flicker since the B-Frames have often larger QP. Default is 0 (not enabled).
Commands
This filter supports the following commands:
quality, level
Set quality level. The value "max" can be used to set the maximum level, currently 6.
sr
Scale the input by applying one of the super-resolution methods based on convolutional
neural networks. Supported models:
• Super-Resolution Convolutional Neural Network model (SRCNN). See
<https://arxiv.org/abs/1501.00092>.
• Efficient Sub-Pixel Convolutional Neural Network model (ESPCN). See
<https://arxiv.org/abs/1609.05158>.
Training scripts as well as scripts for model file (.pb) saving can be found at
<https://github.com/XueweiMeng/sr/tree/sr_dnn_native>. Original repository is at
<https://github.com/HighVoltageRocknRoll/sr.git>.
The filter accepts the following options:
dnn_backend
Specify which DNN backend to use for model loading and execution. This option accepts
the following values:
tensorflow
TensorFlow backend. To enable this backend you need to install the TensorFlow for
C library (see <https://www.tensorflow.org/install/lang_c>) and configure FFmpeg
with "--enable-libtensorflow"
model
Set path to model file specifying network architecture and its parameters. Note that
different backends use different file formats. TensorFlow, OpenVINO backend can load
files for only its format.
scale_factor
Set scale factor for SRCNN model. Allowed values are 2, 3 and 4. Default value is 2.
Scale factor is necessary for SRCNN model, because it accepts input upscaled using
bicubic upscaling with proper scale factor.
To get full functionality (such as async execution), please use the dnn_processing filter.
ssim
Obtain the SSIM (Structural SImilarity Metric) between two input videos.
This filter takes in input two input videos, the first input is considered the "main"
source and is passed unchanged to the output. The second input is used as a "reference"
video for computing the SSIM.
Both video inputs must have the same resolution and pixel format for this filter to work
correctly. Also it assumes that both inputs have the same number of frames, which are
compared one by one.
The filter stores the calculated SSIM of each frame.
The description of the accepted parameters follows.
stats_file, f
If specified the filter will use the named file to save the SSIM of each individual
frame. When filename equals "-" the data is sent to standard output.
The file printed if stats_file is selected, contains a sequence of key/value pairs of the
form key:value for each compared couple of frames.
A description of each shown parameter follows:
n sequential number of the input frame, starting from 1
Y, U, V, R, G, B
SSIM of the compared frames for the component specified by the suffix.
All SSIM of the compared frames for the whole frame.
dB Same as above but in dB representation.
This filter also supports the framesync options.
Examples
• For example:
movie=ref_movie.mpg, setpts=PTS-STARTPTS [main];
[main][ref] ssim="stats_file=stats.log" [out]
On this example the input file being processed is compared with the reference file
ref_movie.mpg. The SSIM of each individual frame is stored in stats.log.
• Another example with both psnr and ssim at same time:
ffmpeg -i main.mpg -i ref.mpg -lavfi "ssim;[0:v][1:v]psnr" -f null -
• Another example with different containers:
ffmpeg -i main.mpg -i ref.mkv -lavfi "[0:v]settb=AVTB,setpts=PTS-STARTPTS[main];[1:v]settb=AVTB,setpts=PTS-STARTPTS[ref];[main][ref]ssim" -f null -
stereo3d
Convert between different stereoscopic image formats.
The filters accept the following options:
in Set stereoscopic image format of input.
Available values for input image formats are:
sbsl
side by side parallel (left eye left, right eye right)
sbsr
side by side crosseye (right eye left, left eye right)
sbs2l
side by side parallel with half width resolution (left eye left, right eye right)
sbs2r
side by side crosseye with half width resolution (right eye left, left eye right)
abl
tbl above-below (left eye above, right eye below)
abr
tbr above-below (right eye above, left eye below)
ab2l
tb2l
above-below with half height resolution (left eye above, right eye below)
ab2r
tb2r
above-below with half height resolution (right eye above, left eye below)
al alternating frames (left eye first, right eye second)
ar alternating frames (right eye first, left eye second)
irl interleaved rows (left eye has top row, right eye starts on next row)
irr interleaved rows (right eye has top row, left eye starts on next row)
icl interleaved columns, left eye first
icr interleaved columns, right eye first
Default value is sbsl.
out Set stereoscopic image format of output.
sbsl
side by side parallel (left eye left, right eye right)
sbsr
side by side crosseye (right eye left, left eye right)
sbs2l
side by side parallel with half width resolution (left eye left, right eye right)
sbs2r
side by side crosseye with half width resolution (right eye left, left eye right)
abl
tbl above-below (left eye above, right eye below)
abr
tbr above-below (right eye above, left eye below)
ab2l
tb2l
above-below with half height resolution (left eye above, right eye below)
ab2r
tb2r
above-below with half height resolution (right eye above, left eye below)
al alternating frames (left eye first, right eye second)
ar alternating frames (right eye first, left eye second)
irl interleaved rows (left eye has top row, right eye starts on next row)
irr interleaved rows (right eye has top row, left eye starts on next row)
arbg
anaglyph red/blue gray (red filter on left eye, blue filter on right eye)
argg
anaglyph red/green gray (red filter on left eye, green filter on right eye)
arcg
anaglyph red/cyan gray (red filter on left eye, cyan filter on right eye)
arch
anaglyph red/cyan half colored (red filter on left eye, cyan filter on right eye)
arcc
anaglyph red/cyan color (red filter on left eye, cyan filter on right eye)
arcd
anaglyph red/cyan color optimized with the least squares projection of dubois (red
filter on left eye, cyan filter on right eye)
agmg
anaglyph green/magenta gray (green filter on left eye, magenta filter on right
eye)
agmh
anaglyph green/magenta half colored (green filter on left eye, magenta filter on
right eye)
agmc
anaglyph green/magenta colored (green filter on left eye, magenta filter on right
eye)
agmd
anaglyph green/magenta color optimized with the least squares projection of dubois
(green filter on left eye, magenta filter on right eye)
aybg
anaglyph yellow/blue gray (yellow filter on left eye, blue filter on right eye)
aybh
anaglyph yellow/blue half colored (yellow filter on left eye, blue filter on right
eye)
aybc
anaglyph yellow/blue colored (yellow filter on left eye, blue filter on right eye)
aybd
anaglyph yellow/blue color optimized with the least squares projection of dubois
(yellow filter on left eye, blue filter on right eye)
ml mono output (left eye only)
mr mono output (right eye only)
chl checkerboard, left eye first
chr checkerboard, right eye first
icl interleaved columns, left eye first
icr interleaved columns, right eye first
hdmi
HDMI frame pack
Default value is arcd.
Examples
• Convert input video from side by side parallel to anaglyph yellow/blue dubois:
stereo3d=sbsl:aybd
• Convert input video from above below (left eye above, right eye below) to side by side
crosseye.
stereo3d=abl:sbsr
streamselect, astreamselect
Select video or audio streams.
The filter accepts the following options:
inputs
Set number of inputs. Default is 2.
map Set input indexes to remap to outputs.
Commands
The "streamselect" and "astreamselect" filter supports the following commands:
map Set input indexes to remap to outputs.
Examples
• Select first 5 seconds 1st stream and rest of time 2nd stream:
sendcmd='5.0 streamselect map 1',streamselect=inputs=2:map=0
• Same as above, but for audio:
asendcmd='5.0 astreamselect map 1',astreamselect=inputs=2:map=0
subtitles
Draw subtitles on top of input video using the libass library.
To enable compilation of this filter you need to configure FFmpeg with "--enable-libass".
This filter also requires a build with libavcodec and libavformat to convert the passed
subtitles file to ASS (Advanced Substation Alpha) subtitles format.
The filter accepts the following options:
filename, f
Set the filename of the subtitle file to read. It must be specified.
original_size
Specify the size of the original video, the video for which the ASS file was composed.
For the syntax of this option, check the "Video size" section in the ffmpeg-utils
manual. Due to a misdesign in ASS aspect ratio arithmetic, this is necessary to
correctly scale the fonts if the aspect ratio has been changed.
fontsdir
Set a directory path containing fonts that can be used by the filter. These fonts
will be used in addition to whatever the font provider uses.
alpha
Process alpha channel, by default alpha channel is untouched.
charenc
Set subtitles input character encoding. "subtitles" filter only. Only useful if not
UTF-8.
stream_index, si
Set subtitles stream index. "subtitles" filter only.
force_style
Override default style or script info parameters of the subtitles. It accepts a string
containing ASS style format "KEY=VALUE" couples separated by ",".
wrap_unicode
Break lines according to the Unicode Line Breaking Algorithm. Availability requires at
least libass release 0.17.0 (or LIBASS_VERSION 0x01600010), and libass must have been
built with libunibreak.
The option is enabled by default except for native ASS.
If the first key is not specified, it is assumed that the first value specifies the
filename.
For example, to render the file sub.srt on top of the input video, use the command:
subtitles=sub.srt
which is equivalent to:
subtitles=filename=sub.srt
To render the default subtitles stream from file video.mkv, use:
subtitles=video.mkv
To render the second subtitles stream from that file, use:
subtitles=video.mkv:si=1
To make the subtitles stream from sub.srt appear in 80% transparent blue "DejaVu Serif",
use:
subtitles=sub.srt:force_style='Fontname=DejaVu Serif,PrimaryColour=&HCCFF0000'
super2xsai
Scale the input by 2x and smooth using the Super2xSaI (Scale and Interpolate) pixel art
scaling algorithm.
Useful for enlarging pixel art images without reducing sharpness.
swaprect
Swap two rectangular objects in video.
This filter accepts the following options:
w Set object width.
h Set object height.
x1 Set 1st rect x coordinate.
y1 Set 1st rect y coordinate.
x2 Set 2nd rect x coordinate.
y2 Set 2nd rect y coordinate.
All expressions are evaluated once for each frame.
The all options are expressions containing the following constants:
w
h The input width and height.
a same as w / h
sar input sample aspect ratio
dar input display aspect ratio, it is the same as (w / h) * sar
n The number of the input frame, starting from 0.
t The timestamp expressed in seconds. It's NAN if the input timestamp is unknown.
pos the position in the file of the input frame, NAN if unknown; deprecated, do not use
Commands
This filter supports the all above options as commands.
swapuv
Swap U & V plane.
tblend
Blend successive video frames.
See blend
telecine
Apply telecine process to the video.
This filter accepts the following options:
first_field
top, t
top field first
bottom, b
bottom field first The default value is "top".
pattern
A string of numbers representing the pulldown pattern you wish to apply. The default
value is 23.
Some typical patterns:
NTSC output (30i):
27.5p: 32222
24p: 23 (classic)
24p: 2332 (preferred)
20p: 33
18p: 334
16p: 3444
PAL output (25i):
27.5p: 12222
24p: 222222222223 ("Euro pulldown")
16.67p: 33
16p: 33333334
thistogram
Compute and draw a color distribution histogram for the input video across time.
Unlike histogram video filter which only shows histogram of single input frame at certain
time, this filter shows also past histograms of number of frames defined by "width"
option.
The computed histogram is a representation of the color component distribution in an
image.
The filter accepts the following options:
width, w
Set width of single color component output. Default value is 0. Value of 0 means
width will be picked from input video. This also set number of passed histograms to
keep. Allowed range is [0, 8192].
display_mode, d
Set display mode. It accepts the following values:
stack
Per color component graphs are placed below each other.
parade
Per color component graphs are placed side by side.
overlay
Presents information identical to that in the "parade", except that the graphs
representing color components are superimposed directly over one another.
Default is "stack".
levels_mode, m
Set mode. Can be either "linear", or "logarithmic". Default is "linear".
components, c
Set what color components to display. Default is 7.
bgopacity, b
Set background opacity. Default is 0.9.
envelope, e
Show envelope. Default is disabled.
ecolor, ec
Set envelope color. Default is "gold".
slide
Set slide mode.
Available values for slide is:
frame
Draw new frame when right border is reached.
replace
Replace old columns with new ones.
scroll
Scroll from right to left.
rscroll
Scroll from left to right.
picture
Draw single picture.
Default is "replace".
threshold
Apply threshold effect to video stream.
This filter needs four video streams to perform thresholding. First stream is stream we
are filtering. Second stream is holding threshold values, third stream is holding min
values, and last, fourth stream is holding max values.
The filter accepts the following option:
planes
Set which planes will be processed, unprocessed planes will be copied. By default
value 0xf, all planes will be processed.
For example if first stream pixel's component value is less then threshold value of pixel
component from 2nd threshold stream, third stream value will picked, otherwise fourth
stream pixel component value will be picked.
Using color source filter one can perform various types of thresholding:
Commands
This filter supports the all options as commands.
Examples
• Binary threshold, using gray color as threshold:
ffmpeg -i 320x240.avi -f lavfi -i color=gray -f lavfi -i color=black -f lavfi -i color=white -lavfi threshold output.avi
• Inverted binary threshold, using gray color as threshold:
ffmpeg -i 320x240.avi -f lavfi -i color=gray -f lavfi -i color=white -f lavfi -i color=black -lavfi threshold output.avi
• Truncate binary threshold, using gray color as threshold:
ffmpeg -i 320x240.avi -f lavfi -i color=gray -i 320x240.avi -f lavfi -i color=gray -lavfi threshold output.avi
• Threshold to zero, using gray color as threshold:
ffmpeg -i 320x240.avi -f lavfi -i color=gray -f lavfi -i color=white -i 320x240.avi -lavfi threshold output.avi
• Inverted threshold to zero, using gray color as threshold:
ffmpeg -i 320x240.avi -f lavfi -i color=gray -i 320x240.avi -f lavfi -i color=white -lavfi threshold output.avi
thumbnail
Select the most representative frame in a given sequence of consecutive frames.
The filter accepts the following options:
n Set the frames batch size to analyze; in a set of n frames, the filter will pick one
of them, and then handle the next batch of n frames until the end. Default is 100.
log Set the log level to display picked frame stats. Default is "info".
Since the filter keeps track of the whole frames sequence, a bigger n value will result in
a higher memory usage, so a high value is not recommended.
Examples
• Extract one picture each 50 frames:
thumbnail=50
• Complete example of a thumbnail creation with ffmpeg:
ffmpeg -i in.avi -vf thumbnail,scale=300:200 -frames:v 1 out.png
tile
Tile several successive frames together.
The untile filter can do the reverse.
The filter accepts the following options:
layout
Set the grid size in the form "COLUMNSxROWS". Range is up to UINT_MAX cells. Default
is "6x5".
nb_frames
Set the maximum number of frames to render in the given area. It must be less than or
equal to wxh. The default value is 0, meaning all the area will be used.
margin
Set the outer border margin in pixels. Range is 0 to 1024. Default is 0.
padding
Set the inner border thickness (i.e. the number of pixels between frames). For more
advanced padding options (such as having different values for the edges), refer to the
pad video filter. Range is 0 to 1024. Default is 0.
color
Specify the color of the unused area. For the syntax of this option, check the "Color"
section in the ffmpeg-utils manual. The default value of color is "black".
overlap
Set the number of frames to overlap when tiling several successive frames together.
The value must be between 0 and nb_frames - 1. Default is 0.
init_padding
Set the number of frames to initially be empty before displaying first output frame.
This controls how soon will one get first output frame. The value must be between 0
and nb_frames - 1. Default is 0.
Examples
• Produce 8x8 PNG tiles of all keyframes (-skip_frame nokey) in a movie:
ffmpeg -skip_frame nokey -i file.avi -vf 'scale=128:72,tile=8x8' -an -vsync 0 keyframes%03d.png
The -vsync 0 is necessary to prevent ffmpeg from duplicating each output frame to
accommodate the originally detected frame rate.
• Display 5 pictures in an area of "3x2" frames, with 7 pixels between them, and 2
pixels of initial margin, using mixed flat and named options:
tile=3x2:nb_frames=5:padding=7:margin=2
tiltandshift
Apply tilt-and-shift effect.
What happens when you invert time and space?
Normally a video is composed of several frames that represent a different instant of time
and shows a scene that evolves in the space captured by the frame. This filter is the
antipode of that concept, taking inspiration from tilt and shift photography.
A filtered frame contains the whole timeline of events composing the sequence, and this is
obtained by placing a slice of pixels from each frame into a single one. However, since
there are no infinite-width frames, this is done up the width of the input frame, and a
video is recomposed by shifting away one column for each subsequent frame. In order to map
space to time, the filter tilts each input frame as well, so that motion is preserved.
This is accomplished by progressively selecting a different column from each input frame.
The end result is a sort of inverted parallax, so that far away objects move much faster
that the ones in the front. The ideal conditions for this video effect are when there is
either very little motion and the backgroud is static, or when there is a lot of motion
and a very wide depth of field (e.g. wide panorama, while moving on a train).
The filter accepts the following parameters:
tilt
Tilt video while shifting (default). When unset, video will be sliding a static image,
composed of the first column of each frame.
start
What to do at the start of filtering (see below).
end What to do at the end of filtering (see below).
hold
How many columns should pass through before start of filtering.
pad How many columns should be inserted before end of filtering.
Normally the filter shifts and tilts from the very first frame, and stops when the last
one is received. However, before filtering starts, normal video may be preseved, so that
the effect is slowly shifted in its place. Similarly, the last video frame may be
reconstructed at the end. Alternatively it is possible to just start and end with black.
none
Filtering starts immediately and ends when the last frame is received.
frame
The first frames or the very last frame are kept intact during processing.
black
Black is padded at the beginning or at the end of filtering.
tinterlace
Perform various types of temporal field interlacing.
Frames are counted starting from 1, so the first input frame is considered odd.
The filter accepts the following options:
mode
Specify the mode of the interlacing. This option can also be specified as a value
alone. See below for a list of values for this option.
Available values are:
merge, 0
Move odd frames into the upper field, even into the lower field, generating a
double height frame at half frame rate.
------> time
Input:
Frame 1 Frame 2 Frame 3 Frame 4
11111 22222 33333 44444
11111 22222 33333 44444
11111 22222 33333 44444
11111 22222 33333 44444
Output:
11111 33333
22222 44444
11111 33333
22222 44444
11111 33333
22222 44444
11111 33333
22222 44444
drop_even, 1
Only output odd frames, even frames are dropped, generating a frame with unchanged
height at half frame rate.
------> time
Input:
Frame 1 Frame 2 Frame 3 Frame 4
11111 22222 33333 44444
11111 22222 33333 44444
11111 22222 33333 44444
11111 22222 33333 44444
Output:
11111 33333
11111 33333
11111 33333
11111 33333
drop_odd, 2
Only output even frames, odd frames are dropped, generating a frame with unchanged
height at half frame rate.
------> time
Input:
Frame 1 Frame 2 Frame 3 Frame 4
11111 22222 33333 44444
11111 22222 33333 44444
11111 22222 33333 44444
11111 22222 33333 44444
Output:
22222 44444
22222 44444
22222 44444
22222 44444
pad, 3
Expand each frame to full height, but pad alternate lines with black, generating a
frame with double height at the same input frame rate.
------> time
Input:
Frame 1 Frame 2 Frame 3 Frame 4
11111 22222 33333 44444
11111 22222 33333 44444
11111 22222 33333 44444
11111 22222 33333 44444
Output:
11111 ..... 33333 .....
..... 22222 ..... 44444
11111 ..... 33333 .....
..... 22222 ..... 44444
11111 ..... 33333 .....
..... 22222 ..... 44444
11111 ..... 33333 .....
..... 22222 ..... 44444
interleave_top, 4
Interleave the upper field from odd frames with the lower field from even frames,
generating a frame with unchanged height at half frame rate.
------> time
Input:
Frame 1 Frame 2 Frame 3 Frame 4
11111<- 22222 33333<- 44444
11111 22222<- 33333 44444<-
11111<- 22222 33333<- 44444
11111 22222<- 33333 44444<-
Output:
11111 33333
22222 44444
11111 33333
22222 44444
interleave_bottom, 5
Interleave the lower field from odd frames with the upper field from even frames,
generating a frame with unchanged height at half frame rate.
------> time
Input:
Frame 1 Frame 2 Frame 3 Frame 4
11111 22222<- 33333 44444<-
11111<- 22222 33333<- 44444
11111 22222<- 33333 44444<-
11111<- 22222 33333<- 44444
Output:
22222 44444
11111 33333
22222 44444
11111 33333
interlacex2, 6
Double frame rate with unchanged height. Frames are inserted each containing the
second temporal field from the previous input frame and the first temporal field
from the next input frame. This mode relies on the top_field_first flag. Useful
for interlaced video displays with no field synchronisation.
------> time
Input:
Frame 1 Frame 2 Frame 3 Frame 4
11111 22222 33333 44444
11111 22222 33333 44444
11111 22222 33333 44444
11111 22222 33333 44444
Output:
11111 22222 22222 33333 33333 44444 44444
11111 11111 22222 22222 33333 33333 44444
11111 22222 22222 33333 33333 44444 44444
11111 11111 22222 22222 33333 33333 44444
mergex2, 7
Move odd frames into the upper field, even into the lower field, generating a
double height frame at same frame rate.
------> time
Input:
Frame 1 Frame 2 Frame 3 Frame 4
11111 22222 33333 44444
11111 22222 33333 44444
11111 22222 33333 44444
11111 22222 33333 44444
Output:
11111 33333 33333 55555
22222 22222 44444 44444
11111 33333 33333 55555
22222 22222 44444 44444
11111 33333 33333 55555
22222 22222 44444 44444
11111 33333 33333 55555
22222 22222 44444 44444
Numeric values are deprecated but are accepted for backward compatibility reasons.
Default mode is "merge".
flags
Specify flags influencing the filter process.
Available value for flags is:
low_pass_filter, vlpf
Enable linear vertical low-pass filtering in the filter. Vertical low-pass
filtering is required when creating an interlaced destination from a progressive
source which contains high-frequency vertical detail. Filtering will reduce
interlace 'twitter' and Moire patterning.
complex_filter, cvlpf
Enable complex vertical low-pass filtering. This will slightly less reduce
interlace 'twitter' and Moire patterning but better retain detail and subjective
sharpness impression.
bypass_il
Bypass already interlaced frames, only adjust the frame rate.
Vertical low-pass filtering and bypassing already interlaced frames can only be
enabled for mode interleave_top and interleave_bottom.
tmedian
Pick median pixels from several successive input video frames.
The filter accepts the following options:
radius
Set radius of median filter. Default is 1. Allowed range is from 1 to 127.
planes
Set which planes to filter. Default value is 15, by which all planes are processed.
percentile
Set median percentile. Default value is 0.5. Default value of 0.5 will pick always
median values, while 0 will pick minimum values, and 1 maximum values.
Commands
This filter supports all above options as commands, excluding option "radius".
tmidequalizer
Apply Temporal Midway Video Equalization effect.
Midway Video Equalization adjusts a sequence of video frames to have the same histograms,
while maintaining their dynamics as much as possible. It's useful for e.g. matching
exposures from a video frames sequence.
This filter accepts the following option:
radius
Set filtering radius. Default is 5. Allowed range is from 1 to 127.
sigma
Set filtering sigma. Default is 0.5. This controls strength of filtering. Setting
this option to 0 effectively does nothing.
planes
Set which planes to process. Default is 15, which is all available planes.
tmix
Mix successive video frames.
A description of the accepted options follows.
frames
The number of successive frames to mix. If unspecified, it defaults to 3.
weights
Specify weight of each input video frame. Each weight is separated by space. If
number of weights is smaller than number of frames last specified weight will be used
for all remaining unset weights.
scale
Specify scale, if it is set it will be multiplied with sum of each weight multiplied
with pixel values to give final destination pixel value. By default scale is auto
scaled to sum of weights.
planes
Set which planes to filter. Default is all. Allowed range is from 0 to 15.
Examples
• Average 7 successive frames:
tmix=frames=7:weights="1 1 1 1 1 1 1"
• Apply simple temporal convolution:
tmix=frames=3:weights="-1 3 -1"
• Similar as above but only showing temporal differences:
tmix=frames=3:weights="-1 2 -1":scale=1
Commands
This filter supports the following commands:
weights
scale
planes
Syntax is same as option with same name.
tonemap
Tone map colors from different dynamic ranges.
This filter expects data in single precision floating point, as it needs to operate on
(and can output) out-of-range values. Another filter, such as zscale, is needed to convert
the resulting frame to a usable format.
The tonemapping algorithms implemented only work on linear light, so input data should be
linearized beforehand (and possibly correctly tagged).
ffmpeg -i INPUT -vf zscale=transfer=linear,tonemap=clip,zscale=transfer=bt709,format=yuv420p OUTPUT
Options
The filter accepts the following options.
tonemap
Set the tone map algorithm to use.
Possible values are:
none
Do not apply any tone map, only desaturate overbright pixels.
clip
Hard-clip any out-of-range values. Use it for perfect color accuracy for in-range
values, while distorting out-of-range values.
linear
Stretch the entire reference gamut to a linear multiple of the display.
gamma
Fit a logarithmic transfer between the tone curves.
reinhard
Preserve overall image brightness with a simple curve, using nonlinear contrast,
which results in flattening details and degrading color accuracy.
hable
Preserve both dark and bright details better than reinhard, at the cost of
slightly darkening everything. Use it when detail preservation is more important
than color and brightness accuracy.
mobius
Smoothly map out-of-range values, while retaining contrast and colors for in-range
material as much as possible. Use it when color accuracy is more important than
detail preservation.
Default is none.
param
Tune the tone mapping algorithm.
This affects the following algorithms:
none
Ignored.
linear
Specifies the scale factor to use while stretching. Default to 1.0.
gamma
Specifies the exponent of the function. Default to 1.8.
clip
Specify an extra linear coefficient to multiply into the signal before clipping.
Default to 1.0.
reinhard
Specify the local contrast coefficient at the display peak. Default to 0.5, which
means that in-gamut values will be about half as bright as when clipping.
hable
Ignored.
mobius
Specify the transition point from linear to mobius transform. Every value below
this point is guaranteed to be mapped 1:1. The higher the value, the more accurate
the result will be, at the cost of losing bright details. Default to 0.3, which
due to the steep initial slope still preserves in-range colors fairly accurately.
desat
Apply desaturation for highlights that exceed this level of brightness. The higher the
parameter, the more color information will be preserved. This setting helps prevent
unnaturally blown-out colors for super-highlights, by (smoothly) turning into white
instead. This makes images feel more natural, at the cost of reducing information
about out-of-range colors.
The default of 2.0 is somewhat conservative and will mostly just apply to skies or
directly sunlit surfaces. A setting of 0.0 disables this option.
This option works only if the input frame has a supported color tag.
peak
Override signal/nominal/reference peak with this value. Useful when the embedded peak
information in display metadata is not reliable or when tone mapping from a lower
range to a higher range.
tpad
Temporarily pad video frames.
The filter accepts the following options:
start
Specify number of delay frames before input video stream. Default is 0.
stop
Specify number of padding frames after input video stream. Set to -1 to pad
indefinitely. Default is 0.
start_mode
Set kind of frames added to beginning of stream. Can be either add or clone. With
add frames of solid-color are added. With clone frames are clones of first frame.
Default is add.
stop_mode
Set kind of frames added to end of stream. Can be either add or clone. With add
frames of solid-color are added. With clone frames are clones of last frame. Default
is add.
start_duration, stop_duration
Specify the duration of the start/stop delay. See the Time duration section in the
ffmpeg-utils(1) manual for the accepted syntax. These options override start and
stop. Default is 0.
color
Specify the color of the padded area. For the syntax of this option, check the "Color"
section in the ffmpeg-utils manual.
The default value of color is "black".
transpose
Transpose rows with columns in the input video and optionally flip it.
It accepts the following parameters:
dir Specify the transposition direction.
Can assume the following values:
0, 4, cclock_flip
Rotate by 90 degrees counterclockwise and vertically flip (default), that is:
L.R L.l
. . -> . .
l.r R.r
1, 5, clock
Rotate by 90 degrees clockwise, that is:
L.R l.L
. . -> . .
l.r r.R
2, 6, cclock
Rotate by 90 degrees counterclockwise, that is:
L.R R.r
. . -> . .
l.r L.l
3, 7, clock_flip
Rotate by 90 degrees clockwise and vertically flip, that is:
L.R r.R
. . -> . .
l.r l.L
For values between 4-7, the transposition is only done if the input video geometry is
portrait and not landscape. These values are deprecated, the "passthrough" option
should be used instead.
Numerical values are deprecated, and should be dropped in favor of symbolic constants.
passthrough
Do not apply the transposition if the input geometry matches the one specified by the
specified value. It accepts the following values:
none
Always apply transposition.
portrait
Preserve portrait geometry (when height >= width).
landscape
Preserve landscape geometry (when width >= height).
Default value is "none".
For example to rotate by 90 degrees clockwise and preserve portrait layout:
transpose=dir=1:passthrough=portrait
The command above can also be specified as:
transpose=1:portrait
transpose_npp
Transpose rows with columns in the input video and optionally flip it. For more in depth
examples see the transpose video filter, which shares mostly the same options.
It accepts the following parameters:
dir Specify the transposition direction.
Can assume the following values:
cclock_flip
Rotate by 90 degrees counterclockwise and vertically flip. (default)
clock
Rotate by 90 degrees clockwise.
cclock
Rotate by 90 degrees counterclockwise.
clock_flip
Rotate by 90 degrees clockwise and vertically flip.
passthrough
Do not apply the transposition if the input geometry matches the one specified by the
specified value. It accepts the following values:
none
Always apply transposition. (default)
portrait
Preserve portrait geometry (when height >= width).
landscape
Preserve landscape geometry (when width >= height).
trim
Trim the input so that the output contains one continuous subpart of the input.
It accepts the following parameters:
start
Specify the time of the start of the kept section, i.e. the frame with the timestamp
start will be the first frame in the output.
end Specify the time of the first frame that will be dropped, i.e. the frame immediately
preceding the one with the timestamp end will be the last frame in the output.
start_pts
This is the same as start, except this option sets the start timestamp in timebase
units instead of seconds.
end_pts
This is the same as end, except this option sets the end timestamp in timebase units
instead of seconds.
duration
The maximum duration of the output in seconds.
start_frame
The number of the first frame that should be passed to the output.
end_frame
The number of the first frame that should be dropped.
start, end, and duration are expressed as time duration specifications; see the Time
duration section in the ffmpeg-utils(1) manual for the accepted syntax.
Note that the first two sets of the start/end options and the duration option look at the
frame timestamp, while the _frame variants simply count the frames that pass through the
filter. Also note that this filter does not modify the timestamps. If you wish for the
output timestamps to start at zero, insert a setpts filter after the trim filter.
If multiple start or end options are set, this filter tries to be greedy and keep all the
frames that match at least one of the specified constraints. To keep only the part that
matches all the constraints at once, chain multiple trim filters.
The defaults are such that all the input is kept. So it is possible to set e.g. just the
end values to keep everything before the specified time.
Examples:
• Drop everything except the second minute of input:
ffmpeg -i INPUT -vf trim=60:120
• Keep only the first second:
ffmpeg -i INPUT -vf trim=duration=1
unpremultiply
Apply alpha unpremultiply effect to input video stream using first plane of second stream
as alpha.
Both streams must have same dimensions and same pixel format.
The filter accepts the following option:
planes
Set which planes will be processed, unprocessed planes will be copied. By default
value 0xf, all planes will be processed.
If the format has 1 or 2 components, then luma is bit 0. If the format has 3 or 4
components: for RGB formats bit 0 is green, bit 1 is blue and bit 2 is red; for YUV
formats bit 0 is luma, bit 1 is chroma-U and bit 2 is chroma-V. If present, the alpha
channel is always the last bit.
inplace
Do not require 2nd input for processing, instead use alpha plane from input stream.
unsharp
Sharpen or blur the input video.
It accepts the following parameters:
luma_msize_x, lx
Set the luma matrix horizontal size. It must be an odd integer between 3 and 23. The
default value is 5.
luma_msize_y, ly
Set the luma matrix vertical size. It must be an odd integer between 3 and 23. The
default value is 5.
luma_amount, la
Set the luma effect strength. It must be a floating point number, reasonable values
lay between -1.5 and 1.5.
Negative values will blur the input video, while positive values will sharpen it, a
value of zero will disable the effect.
Default value is 1.0.
chroma_msize_x, cx
Set the chroma matrix horizontal size. It must be an odd integer between 3 and 23. The
default value is 5.
chroma_msize_y, cy
Set the chroma matrix vertical size. It must be an odd integer between 3 and 23. The
default value is 5.
chroma_amount, ca
Set the chroma effect strength. It must be a floating point number, reasonable values
lay between -1.5 and 1.5.
Negative values will blur the input video, while positive values will sharpen it, a
value of zero will disable the effect.
Default value is 0.0.
alpha_msize_x, ax
Set the alpha matrix horizontal size. It must be an odd integer between 3 and 23. The
default value is 5.
alpha_msize_y, ay
Set the alpha matrix vertical size. It must be an odd integer between 3 and 23. The
default value is 5.
alpha_amount, aa
Set the alpha effect strength. It must be a floating point number, reasonable values
lay between -1.5 and 1.5.
Negative values will blur the input video, while positive values will sharpen it, a
value of zero will disable the effect.
Default value is 0.0.
All parameters are optional and default to the equivalent of the string '5:5:1.0:5:5:0.0'.
Examples
• Apply strong luma sharpen effect:
unsharp=luma_msize_x=7:luma_msize_y=7:luma_amount=2.5
• Apply a strong blur of both luma and chroma parameters:
unsharp=7:7:-2:7:7:-2
untile
Decompose a video made of tiled images into the individual images.
The frame rate of the output video is the frame rate of the input video multiplied by the
number of tiles.
This filter does the reverse of tile.
The filter accepts the following options:
layout
Set the grid size (i.e. the number of lines and columns). For the syntax of this
option, check the "Video size" section in the ffmpeg-utils manual.
Examples
• Produce a 1-second video from a still image file made of 25 frames stacked vertically,
like an analogic film reel:
ffmpeg -r 1 -i image.jpg -vf untile=1x25 movie.mkv
uspp
Apply ultra slow/simple postprocessing filter that compresses and decompresses the image
at several (or - in the case of quality level 8 - all) shifts and average the results.
The way this differs from the behavior of spp is that uspp actually encodes & decodes each
case with libavcodec Snow, whereas spp uses a simplified intra only 8x8 DCT similar to
MJPEG.
This filter is not available in ffmpeg versions between 5.0 and 6.0.
The filter accepts the following options:
quality
Set quality. This option defines the number of levels for averaging. It accepts an
integer in the range 0-8. If set to 0, the filter will have no effect. A value of 8
means the higher quality. For each increment of that value the speed drops by a factor
of approximately 2. Default value is 3.
qp Force a constant quantization parameter. If not set, the filter will use the QP from
the video stream (if available).
codec
Use specified codec instead of snow.
v360
Convert 360 videos between various formats.
The filter accepts the following options:
input
output
Set format of the input/output video.
Available formats:
e
equirect
Equirectangular projection.
c3x2
c6x1
c1x6
Cubemap with 3x2/6x1/1x6 layout.
Format specific options:
in_pad
out_pad
Set padding proportion for the input/output cubemap. Values in decimals.
Example values:
0 No padding.
0.01
1% of face is padding. For example, with 1920x1280 resolution face size
would be 640x640 and padding would be 3 pixels from each side. (640 * 0.01
= 6 pixels)
Default value is @samp{0}. Maximum value is @samp{0.1}.
fin_pad
fout_pad
Set fixed padding for the input/output cubemap. Values in pixels.
Default value is @samp{0}. If greater than zero it overrides other padding
options.
in_forder
out_forder
Set order of faces for the input/output cubemap. Choose one direction for each
position.
Designation of directions:
r right
l left
u up
d down
f forward
b back
Default value is @samp{rludfb}.
in_frot
out_frot
Set rotation of faces for the input/output cubemap. Choose one angle for each
position.
Designation of angles:
0 0 degrees clockwise
1 90 degrees clockwise
2 180 degrees clockwise
3 270 degrees clockwise
Default value is @samp{000000}.
eac Equi-Angular Cubemap.
flat
gnomonic
rectilinear
Regular video.
Format specific options:
h_fov
v_fov
d_fov
Set output horizontal/vertical/diagonal field of view. Values in degrees.
If diagonal field of view is set it overrides horizontal and vertical field of
view.
ih_fov
iv_fov
id_fov
Set input horizontal/vertical/diagonal field of view. Values in degrees.
If diagonal field of view is set it overrides horizontal and vertical field of
view.
dfisheye
Dual fisheye.
Format specific options:
h_fov
v_fov
d_fov
Set output horizontal/vertical/diagonal field of view. Values in degrees.
If diagonal field of view is set it overrides horizontal and vertical field of
view.
ih_fov
iv_fov
id_fov
Set input horizontal/vertical/diagonal field of view. Values in degrees.
If diagonal field of view is set it overrides horizontal and vertical field of
view.
barrel
fb
barrelsplit
Facebook's 360 formats.
sg Stereographic format.
Format specific options:
h_fov
v_fov
d_fov
Set output horizontal/vertical/diagonal field of view. Values in degrees.
If diagonal field of view is set it overrides horizontal and vertical field of
view.
ih_fov
iv_fov
id_fov
Set input horizontal/vertical/diagonal field of view. Values in degrees.
If diagonal field of view is set it overrides horizontal and vertical field of
view.
mercator
Mercator format.
ball
Ball format, gives significant distortion toward the back.
hammer
Hammer-Aitoff map projection format.
sinusoidal
Sinusoidal map projection format.
fisheye
Fisheye projection.
Format specific options:
h_fov
v_fov
d_fov
Set output horizontal/vertical/diagonal field of view. Values in degrees.
If diagonal field of view is set it overrides horizontal and vertical field of
view.
ih_fov
iv_fov
id_fov
Set input horizontal/vertical/diagonal field of view. Values in degrees.
If diagonal field of view is set it overrides horizontal and vertical field of
view.
pannini
Pannini projection.
Format specific options:
h_fov
Set output pannini parameter.
ih_fov
Set input pannini parameter.
cylindrical
Cylindrical projection.
Format specific options:
h_fov
v_fov
d_fov
Set output horizontal/vertical/diagonal field of view. Values in degrees.
If diagonal field of view is set it overrides horizontal and vertical field of
view.
ih_fov
iv_fov
id_fov
Set input horizontal/vertical/diagonal field of view. Values in degrees.
If diagonal field of view is set it overrides horizontal and vertical field of
view.
perspective
Perspective projection. (output only)
Format specific options:
v_fov
Set perspective parameter.
tetrahedron
Tetrahedron projection.
tsp Truncated square pyramid projection.
he
hequirect
Half equirectangular projection.
equisolid
Equisolid format.
Format specific options:
h_fov
v_fov
d_fov
Set output horizontal/vertical/diagonal field of view. Values in degrees.
If diagonal field of view is set it overrides horizontal and vertical field of
view.
ih_fov
iv_fov
id_fov
Set input horizontal/vertical/diagonal field of view. Values in degrees.
If diagonal field of view is set it overrides horizontal and vertical field of
view.
og Orthographic format.
Format specific options:
h_fov
v_fov
d_fov
Set output horizontal/vertical/diagonal field of view. Values in degrees.
If diagonal field of view is set it overrides horizontal and vertical field of
view.
ih_fov
iv_fov
id_fov
Set input horizontal/vertical/diagonal field of view. Values in degrees.
If diagonal field of view is set it overrides horizontal and vertical field of
view.
octahedron
Octahedron projection.
cylindricalea
Cylindrical Equal Area projection.
interp
Set interpolation method.Note: more complex interpolation methods require much more
memory to run.
Available methods:
near
nearest
Nearest neighbour.
line
linear
Bilinear interpolation.
lagrange9
Lagrange9 interpolation.
cube
cubic
Bicubic interpolation.
lanc
lanczos
Lanczos interpolation.
sp16
spline16
Spline16 interpolation.
gauss
gaussian
Gaussian interpolation.
mitchell
Mitchell interpolation.
Default value is @samp{line}.
w
h Set the output video resolution.
Default resolution depends on formats.
in_stereo
out_stereo
Set the input/output stereo format.
2d 2D mono
sbs Side by side
tb Top bottom
Default value is @samp{2d} for input and output format.
yaw
pitch
roll
Set rotation for the output video. Values in degrees.
rorder
Set rotation order for the output video. Choose one item for each position.
y, Y
yaw
p, P
pitch
r, R
roll
Default value is @samp{ypr}.
h_flip
v_flip
d_flip
Flip the output video horizontally(swaps left-right)/vertically(swaps
up-down)/in-depth(swaps back-forward). Boolean values.
ih_flip
iv_flip
Set if input video is flipped horizontally/vertically. Boolean values.
in_trans
Set if input video is transposed. Boolean value, by default disabled.
out_trans
Set if output video needs to be transposed. Boolean value, by default disabled.
h_offset
v_offset
Set output horizontal/vertical off-axis offset. Default is set to 0. Allowed range is
from -1 to 1.
alpha_mask
Build mask in alpha plane for all unmapped pixels by marking them fully transparent.
Boolean value, by default disabled.
reset_rot
Reset rotation of output video. Boolean value, by default disabled.
Examples
• Convert equirectangular video to cubemap with 3x2 layout and 1% padding using bicubic
interpolation:
ffmpeg -i input.mkv -vf v360=e:c3x2:cubic:out_pad=0.01 output.mkv
• Extract back view of Equi-Angular Cubemap:
ffmpeg -i input.mkv -vf v360=eac:flat:yaw=180 output.mkv
• Convert transposed and horizontally flipped Equi-Angular Cubemap in side-by-side
stereo format to equirectangular top-bottom stereo format:
v360=eac:equirect:in_stereo=sbs:in_trans=1:ih_flip=1:out_stereo=tb
Commands
This filter supports subset of above options as commands.
vaguedenoiser
Apply a wavelet based denoiser.
It transforms each frame from the video input into the wavelet domain, using Cohen-
Daubechies-Feauveau 9/7. Then it applies some filtering to the obtained coefficients. It
does an inverse wavelet transform after. Due to wavelet properties, it should give a nice
smoothed result, and reduced noise, without blurring picture features.
This filter accepts the following options:
threshold
The filtering strength. The higher, the more filtered the video will be. Hard
thresholding can use a higher threshold than soft thresholding before the video looks
overfiltered. Default value is 2.
method
The filtering method the filter will use.
It accepts the following values:
hard
All values under the threshold will be zeroed.
soft
All values under the threshold will be zeroed. All values above will be reduced by
the threshold.
garrote
Scales or nullifies coefficients - intermediary between (more) soft and (less)
hard thresholding.
Default is garrote.
nsteps
Number of times, the wavelet will decompose the picture. Picture can't be decomposed
beyond a particular point (typically, 8 for a 640x480 frame - as 2^9 = 512 > 480).
Valid values are integers between 1 and 32. Default value is 6.
percent
Partial of full denoising (limited coefficients shrinking), from 0 to 100. Default
value is 85.
planes
A list of the planes to process. By default all planes are processed.
type
The threshold type the filter will use.
It accepts the following values:
universal
Threshold used is same for all decompositions.
bayes
Threshold used depends also on each decomposition coefficients.
Default is universal.
varblur
Apply variable blur filter by using 2nd video stream to set blur radius. The 2nd stream
must have the same dimensions.
This filter accepts the following options:
min_r
Set min allowed radius. Allowed range is from 0 to 254. Default is 0.
max_r
Set max allowed radius. Allowed range is from 1 to 255. Default is 8.
planes
Set which planes to process. By default, all are used.
The "varblur" filter also supports the framesync options.
Commands
This filter supports all the above options as commands.
vectorscope
Display 2 color component values in the two dimensional graph (which is called a
vectorscope).
This filter accepts the following options:
mode, m
Set vectorscope mode.
It accepts the following values:
gray
tint
Gray values are displayed on graph, higher brightness means more pixels have same
component color value on location in graph. This is the default mode.
color
Gray values are displayed on graph. Surrounding pixels values which are not
present in video frame are drawn in gradient of 2 color components which are set
by option "x" and "y". The 3rd color component is static.
color2
Actual color components values present in video frame are displayed on graph.
color3
Similar as color2 but higher frequency of same values "x" and "y" on graph
increases value of another color component, which is luminance by default values
of "x" and "y".
color4
Actual colors present in video frame are displayed on graph. If two different
colors map to same position on graph then color with higher value of component not
present in graph is picked.
color5
Gray values are displayed on graph. Similar to "color" but with 3rd color
component picked from radial gradient.
x Set which color component will be represented on X-axis. Default is 1.
y Set which color component will be represented on Y-axis. Default is 2.
intensity, i
Set intensity, used by modes: gray, color, color3 and color5 for increasing brightness
of color component which represents frequency of (X, Y) location in graph.
envelope, e
none
No envelope, this is default.
instant
Instant envelope, even darkest single pixel will be clearly highlighted.
peak
Hold maximum and minimum values presented in graph over time. This way you can
still spot out of range values without constantly looking at vectorscope.
peak+instant
Peak and instant envelope combined together.
graticule, g
Set what kind of graticule to draw.
none
green
color
invert
opacity, o
Set graticule opacity.
flags, f
Set graticule flags.
white
Draw graticule for white point.
black
Draw graticule for black point.
name
Draw color points short names.
bgopacity, b
Set background opacity.
lthreshold, l
Set low threshold for color component not represented on X or Y axis. Values lower
than this value will be ignored. Default is 0. Note this value is multiplied with
actual max possible value one pixel component can have. So for 8-bit input and low
threshold value of 0.1 actual threshold is 0.1 * 255 = 25.
hthreshold, h
Set high threshold for color component not represented on X or Y axis. Values higher
than this value will be ignored. Default is 1. Note this value is multiplied with
actual max possible value one pixel component can have. So for 8-bit input and high
threshold value of 0.9 actual threshold is 0.9 * 255 = 230.
colorspace, c
Set what kind of colorspace to use when drawing graticule.
auto
601
709
Default is auto.
tint0, t0
tint1, t1
Set color tint for gray/tint vectorscope mode. By default both options are zero. This
means no tint, and output will remain gray.
vidstabdetect
Analyze video stabilization/deshaking. Perform pass 1 of 2, see vidstabtransform for pass
2.
This filter generates a file with relative translation and rotation transform information
about subsequent frames, which is then used by the vidstabtransform filter.
To enable compilation of this filter you need to configure FFmpeg with
"--enable-libvidstab".
This filter accepts the following options:
result
Set the path to the file used to write the transforms information. Default value is
transforms.trf.
shakiness
Set how shaky the video is and how quick the camera is. It accepts an integer in the
range 1-10, a value of 1 means little shakiness, a value of 10 means strong shakiness.
Default value is 5.
accuracy
Set the accuracy of the detection process. It must be a value in the range 1-15. A
value of 1 means low accuracy, a value of 15 means high accuracy. Default value is 15.
stepsize
Set stepsize of the search process. The region around minimum is scanned with 1 pixel
resolution. Default value is 6.
mincontrast
Set minimum contrast. Below this value a local measurement field is discarded. Must be
a floating point value in the range 0-1. Default value is 0.3.
tripod
Set reference frame number for tripod mode.
If enabled, the motion of the frames is compared to a reference frame in the filtered
stream, identified by the specified number. The idea is to compensate all movements in
a more-or-less static scene and keep the camera view absolutely still.
If set to 0, it is disabled. The frames are counted starting from 1.
show
Show fields and transforms in the resulting frames. It accepts an integer in the range
0-2. Default value is 0, which disables any visualization.
fileformat
Format for the transforms data file to be written. Acceptable values are
ascii
Human-readable plain text
binary
Binary format, roughly 40% smaller than "ascii". (default)
Examples
• Use default values:
vidstabdetect
• Analyze strongly shaky movie and put the results in file mytransforms.trf:
vidstabdetect=shakiness=10:accuracy=15:result="mytransforms.trf"
• Visualize the result of internal transformations in the resulting video:
vidstabdetect=show=1
• Analyze a video with medium shakiness using ffmpeg:
ffmpeg -i input -vf vidstabdetect=shakiness=5:show=1 dummy.avi
vidstabtransform
Video stabilization/deshaking: pass 2 of 2, see vidstabdetect for pass 1.
Read a file with transform information for each frame and apply/compensate them. Together
with the vidstabdetect filter this can be used to deshake videos. See also
<http://public.hronopik.de/vid.stab>. It is important to also use the unsharp filter, see
below.
To enable compilation of this filter you need to configure FFmpeg with
"--enable-libvidstab".
Options
input
Set path to the file used to read the transforms. Default value is transforms.trf.
smoothing
Set the number of frames (value*2 + 1) used for lowpass filtering the camera
movements. Default value is 10.
For example a number of 10 means that 21 frames are used (10 in the past and 10 in the
future) to smoothen the motion in the video. A larger value leads to a smoother video,
but limits the acceleration of the camera (pan/tilt movements). 0 is a special case
where a static camera is simulated.
optalgo
Set the camera path optimization algorithm.
Accepted values are:
gauss
gaussian kernel low-pass filter on camera motion (default)
avg averaging on transformations
maxshift
Set maximal number of pixels to translate frames. Default value is -1, meaning no
limit.
maxangle
Set maximal angle in radians (degree*PI/180) to rotate frames. Default value is -1,
meaning no limit.
crop
Specify how to deal with borders that may be visible due to movement compensation.
Available values are:
keep
keep image information from previous frame (default)
black
fill the border black
invert
Invert transforms if set to 1. Default value is 0.
relative
Consider transforms as relative to previous frame if set to 1, absolute if set to 0.
Default value is 0.
zoom
Set percentage to zoom. A positive value will result in a zoom-in effect, a negative
value in a zoom-out effect. Default value is 0 (no zoom).
optzoom
Set optimal zooming to avoid borders.
Accepted values are:
0 disabled
1 optimal static zoom value is determined (only very strong movements will lead to
visible borders) (default)
2 optimal adaptive zoom value is determined (no borders will be visible), see
zoomspeed
Note that the value given at zoom is added to the one calculated here.
zoomspeed
Set percent to zoom maximally each frame (enabled when optzoom is set to 2). Range is
from 0 to 5, default value is 0.25.
interpol
Specify type of interpolation.
Available values are:
no no interpolation
linear
linear only horizontal
bilinear
linear in both directions (default)
bicubic
cubic in both directions (slow)
tripod
Enable virtual tripod mode if set to 1, which is equivalent to
"relative=0:smoothing=0". Default value is 0.
Use also "tripod" option of vidstabdetect.
debug
Increase log verbosity if set to 1. Also the detected global motions are written to
the temporary file global_motions.trf. Default value is 0.
Examples
• Use ffmpeg for a typical stabilization with default values:
ffmpeg -i inp.mpeg -vf vidstabtransform,unsharp=5:5:0.8:3:3:0.4 inp_stabilized.mpeg
Note the use of the unsharp filter which is always recommended.
• Zoom in a bit more and load transform data from a given file:
vidstabtransform=zoom=5:input="mytransforms.trf"
• Smoothen the video even more:
vidstabtransform=smoothing=30
vflip
Flip the input video vertically.
For example, to vertically flip a video with ffmpeg:
ffmpeg -i in.avi -vf "vflip" out.avi
vfrdet
Detect variable frame rate video.
This filter tries to detect if the input is variable or constant frame rate.
At end it will output number of frames detected as having variable delta pts, and ones
with constant delta pts. If there was frames with variable delta, than it will also show
min, max and average delta encountered.
vibrance
Boost or alter saturation.
The filter accepts the following options:
intensity
Set strength of boost if positive value or strength of alter if negative value.
Default is 0. Allowed range is from -2 to 2.
rbal
Set the red balance. Default is 1. Allowed range is from -10 to 10.
gbal
Set the green balance. Default is 1. Allowed range is from -10 to 10.
bbal
Set the blue balance. Default is 1. Allowed range is from -10 to 10.
rlum
Set the red luma coefficient.
glum
Set the green luma coefficient.
blum
Set the blue luma coefficient.
alternate
If "intensity" is negative and this is set to 1, colors will change, otherwise colors
will be less saturated, more towards gray.
Commands
This filter supports the all above options as commands.
vif
Obtain the average VIF (Visual Information Fidelity) between two input videos.
This filter takes two input videos.
Both input videos must have the same resolution and pixel format for this filter to work
correctly. Also it assumes that both inputs have the same number of frames, which are
compared one by one.
The obtained average VIF score is printed through the logging system.
The filter stores the calculated VIF score of each frame.
This filter also supports the framesync options.
In the below example the input file main.mpg being processed is compared with the
reference file ref.mpg.
ffmpeg -i main.mpg -i ref.mpg -lavfi vif -f null -
vignette
Make or reverse a natural vignetting effect.
The filter accepts the following options:
angle, a
Set lens angle expression as a number of radians.
The value is clipped in the "[0,PI/2]" range.
Default value: "PI/5"
x0
y0 Set center coordinates expressions. Respectively "w/2" and "h/2" by default.
mode
Set forward/backward mode.
Available modes are:
forward
The larger the distance from the central point, the darker the image becomes.
backward
The larger the distance from the central point, the brighter the image becomes.
This can be used to reverse a vignette effect, though there is no automatic
detection to extract the lens angle and other settings (yet). It can also be used
to create a burning effect.
Default value is forward.
eval
Set evaluation mode for the expressions (angle, x0, y0).
It accepts the following values:
init
Evaluate expressions only once during the filter initialization.
frame
Evaluate expressions for each incoming frame. This is way slower than the init
mode since it requires all the scalers to be re-computed, but it allows advanced
dynamic expressions.
Default value is init.
dither
Set dithering to reduce the circular banding effects. Default is 1 (enabled).
aspect
Set vignette aspect. This setting allows one to adjust the shape of the vignette.
Setting this value to the SAR of the input will make a rectangular vignetting
following the dimensions of the video.
Default is "1/1".
Expressions
The alpha, x0 and y0 expressions can contain the following parameters.
w
h input width and height
n the number of input frame, starting from 0
pts the PTS (Presentation TimeStamp) time of the filtered video frame, expressed in TB
units, NAN if undefined
r frame rate of the input video, NAN if the input frame rate is unknown
t the PTS (Presentation TimeStamp) of the filtered video frame, expressed in seconds,
NAN if undefined
tb time base of the input video
Examples
• Apply simple strong vignetting effect:
vignette=PI/4
• Make a flickering vignetting:
vignette='PI/4+random(1)*PI/50':eval=frame
vmafmotion
Obtain the average VMAF motion score of a video. It is one of the component metrics of
VMAF.
The obtained average motion score is printed through the logging system.
The filter accepts the following options:
stats_file
If specified, the filter will use the named file to save the motion score of each
frame with respect to the previous frame. When filename equals "-" the data is sent
to standard output.
Example:
ffmpeg -i ref.mpg -vf vmafmotion -f null -
vstack
Stack input videos vertically.
All streams must be of same pixel format and of same width.
Note that this filter is faster than using overlay and pad filter to create same output.
The filter accepts the following options:
inputs
Set number of input streams. Default is 2.
shortest
If set to 1, force the output to terminate when the shortest input terminates. Default
value is 0.
w3fdif
Deinterlace the input video ("w3fdif" stands for "Weston 3 Field Deinterlacing Filter").
Based on the process described by Martin Weston for BBC R&D, and implemented based on the
de-interlace algorithm written by Jim Easterbrook for BBC R&D, the Weston 3 field
deinterlacing filter uses filter coefficients calculated by BBC R&D.
This filter uses field-dominance information in frame to decide which of each pair of
fields to place first in the output. If it gets it wrong use setfield filter before
"w3fdif" filter.
There are two sets of filter coefficients, so called "simple" and "complex". Which set of
filter coefficients is used can be set by passing an optional parameter:
filter
Set the interlacing filter coefficients. Accepts one of the following values:
simple
Simple filter coefficient set.
complex
More-complex filter coefficient set.
Default value is complex.
mode
The interlacing mode to adopt. It accepts one of the following values:
frame
Output one frame for each frame.
field
Output one frame for each field.
The default value is "field".
parity
The picture field parity assumed for the input interlaced video. It accepts one of the
following values:
tff Assume the top field is first.
bff Assume the bottom field is first.
auto
Enable automatic detection of field parity.
The default value is "auto". If the interlacing is unknown or the decoder does not
export this information, top field first will be assumed.
deint
Specify which frames to deinterlace. Accepts one of the following values:
all Deinterlace all frames,
interlaced
Only deinterlace frames marked as interlaced.
Default value is all.
Commands
This filter supports same commands as options.
waveform
Video waveform monitor.
The waveform monitor plots color component intensity. By default luma only. Each column of
the waveform corresponds to a column of pixels in the source video.
It accepts the following options:
mode, m
Can be either "row", or "column". Default is "column". In row mode, the graph on the
left side represents color component value 0 and the right side represents value =
255. In column mode, the top side represents color component value = 0 and bottom side
represents value = 255.
intensity, i
Set intensity. Smaller values are useful to find out how many values of the same
luminance are distributed across input rows/columns. Default value is 0.04. Allowed
range is [0, 1].
mirror, r
Set mirroring mode. 0 means unmirrored, 1 means mirrored. In mirrored mode, higher
values will be represented on the left side for "row" mode and at the top for "column"
mode. Default is 1 (mirrored).
display, d
Set display mode. It accepts the following values:
overlay
Presents information identical to that in the "parade", except that the graphs
representing color components are superimposed directly over one another.
This display mode makes it easier to spot relative differences or similarities in
overlapping areas of the color components that are supposed to be identical, such
as neutral whites, grays, or blacks.
stack
Display separate graph for the color components side by side in "row" mode or one
below the other in "column" mode.
parade
Display separate graph for the color components side by side in "column" mode or
one below the other in "row" mode.
Using this display mode makes it easy to spot color casts in the highlights and
shadows of an image, by comparing the contours of the top and the bottom graphs of
each waveform. Since whites, grays, and blacks are characterized by exactly equal
amounts of red, green, and blue, neutral areas of the picture should display three
waveforms of roughly equal width/height. If not, the correction is easy to perform
by making level adjustments the three waveforms.
Default is "stack".
components, c
Set which color components to display. Default is 1, which means only luma or red
color component if input is in RGB colorspace. If is set for example to 7 it will
display all 3 (if) available color components.
envelope, e
none
No envelope, this is default.
instant
Instant envelope, minimum and maximum values presented in graph will be easily
visible even with small "step" value.
peak
Hold minimum and maximum values presented in graph across time. This way you can
still spot out of range values without constantly looking at waveforms.
peak+instant
Peak and instant envelope combined together.
filter, f
lowpass
No filtering, this is default.
flat
Luma and chroma combined together.
aflat
Similar as above, but shows difference between blue and red chroma.
xflat
Similar as above, but use different colors.
yflat
Similar as above, but again with different colors.
chroma
Displays only chroma.
color
Displays actual color value on waveform.
acolor
Similar as above, but with luma showing frequency of chroma values.
graticule, g
Set which graticule to display.
none
Do not display graticule.
green
Display green graticule showing legal broadcast ranges.
orange
Display orange graticule showing legal broadcast ranges.
invert
Display invert graticule showing legal broadcast ranges.
opacity, o
Set graticule opacity.
flags, fl
Set graticule flags.
numbers
Draw numbers above lines. By default enabled.
dots
Draw dots instead of lines.
scale, s
Set scale used for displaying graticule.
digital
millivolts
ire
Default is digital.
bgopacity, b
Set background opacity.
tint0, t0
tint1, t1
Set tint for output. Only used with lowpass filter and when display is not overlay
and input pixel formats are not RGB.
fitmode, fm
Set sample aspect ratio of video output frames. Can be used to configure waveform so
it is not streched too much in one of directions.
none
Set sample aspect ration to 1/1.
size
Set sample aspect ratio to match input size of video
Default is none.
input
Set input formats for filter to pick from. Can be all, for selecting from all
available formats, or first, for selecting first available format. Default is first.
weave, doubleweave
The "weave" takes a field-based video input and join each two sequential fields into
single frame, producing a new double height clip with half the frame rate and half the
frame count.
The "doubleweave" works same as "weave" but without halving frame rate and frame count.
It accepts the following option:
first_field
Set first field. Available values are:
top, t
Set the frame as top-field-first.
bottom, b
Set the frame as bottom-field-first.
Examples
• Interlace video using select and separatefields filter:
separatefields,select=eq(mod(n,4),0)+eq(mod(n,4),3),weave
xbr
Apply the xBR high-quality magnification filter which is designed for pixel art. It
follows a set of edge-detection rules, see
<https://forums.libretro.com/t/xbr-algorithm-tutorial/123>.
It accepts the following option:
n Set the scaling dimension: 2 for "2xBR", 3 for "3xBR" and 4 for "4xBR". Default is 3.
xcorrelate
Apply normalized cross-correlation between first and second input video stream.
Second input video stream dimensions must be lower than first input video stream.
The filter accepts the following options:
planes
Set which planes to process.
secondary
Set which secondary video frames will be processed from second input video stream, can
be first or all. Default is all.
The "xcorrelate" filter also supports the framesync options.
xfade
Apply cross fade from one input video stream to another input video stream. The cross
fade is applied for specified duration.
Both inputs must be constant frame-rate and have the same resolution, pixel format, frame
rate and timebase.
The filter accepts the following options:
transition
Set one of available transition effects:
custom
fade
wipeleft
wiperight
wipeup
wipedown
slideleft
slideright
slideup
slidedown
circlecrop
rectcrop
distance
fadeblack
fadewhite
radial
smoothleft
smoothright
smoothup
smoothdown
circleopen
circleclose
vertopen
vertclose
horzopen
horzclose
dissolve
pixelize
diagtl
diagtr
diagbl
diagbr
hlslice
hrslice
vuslice
vdslice
hblur
fadegrays
wipetl
wipetr
wipebl
wipebr
squeezeh
squeezev
zoomin
fadefast
fadeslow
hlwind
hrwind
vuwind
vdwind
coverleft
coverright
coverup
coverdown
revealleft
revealright
revealup
revealdown
Default transition effect is fade.
duration
Set cross fade duration in seconds. Range is 0 to 60 seconds. Default duration is 1
second.
offset
Set cross fade start relative to first input stream in seconds. Default offset is 0.
expr
Set expression for custom transition effect.
The expressions can use the following variables and functions:
X
Y The coordinates of the current sample.
W
H The width and height of the image.
P Progress of transition effect.
PLANE
Currently processed plane.
A Return value of first input at current location and plane.
B Return value of second input at current location and plane.
a0(x, y)
a1(x, y)
a2(x, y)
a3(x, y)
Return the value of the pixel at location (x,y) of the first/second/third/fourth
component of first input.
b0(x, y)
b1(x, y)
b2(x, y)
b3(x, y)
Return the value of the pixel at location (x,y) of the first/second/third/fourth
component of second input.
Examples
• Cross fade from one input video to another input video, with fade transition and
duration of transition of 2 seconds starting at offset of 5 seconds:
ffmpeg -i first.mp4 -i second.mp4 -filter_complex xfade=transition=fade:duration=2:offset=5 output.mp4
xmedian
Pick median pixels from several input videos.
The filter accepts the following options:
inputs
Set number of inputs. Default is 3. Allowed range is from 3 to 255. If number of
inputs is even number, than result will be mean value between two median values.
planes
Set which planes to filter. Default value is 15, by which all planes are processed.
percentile
Set median percentile. Default value is 0.5. Default value of 0.5 will pick always
median values, while 0 will pick minimum values, and 1 maximum values.
Commands
This filter supports all above options as commands, excluding option "inputs".
xpsnr
Obtain the average (across all input frames) and minimum (across all color plane averages)
eXtended Perceptually weighted peak Signal-to-Noise Ratio (XPSNR) between two input
videos.
The XPSNR is a low-complexity psychovisually motivated distortion measurement algorithm
for assessing the difference between two video streams or images. This is especially
useful for objectively quantifying the distortions caused by video and image codecs, as an
alternative to a formal subjective test. The logarithmic XPSNR output values are in a
similar range as those of traditional psnr assessments but better reflect human
impressions of visual coding quality. More details on the XPSNR measure, which essentially
represents a blockwise weighted variant of the PSNR measure, can be found in the following
freely available papers:
• C. R. Helmrich, M. Siekmann, S. Becker, S. Bosse, D. Marpe, and T. Wiegand, "XPSNR: A
Low-Complexity Extension of the Perceptually Weighted Peak Signal-to-Noise Ratio for
High-Resolution Video Quality Assessment," in Proc. IEEE Int. Conf. Acoustics, Speech,
Sig. Process. (ICASSP), virt./online, May 2020. <www.ecodis.de/xpsnr.htm>
• C. R. Helmrich, S. Bosse, H. Schwarz, D. Marpe, and T. Wiegand, "A Study of the
Extended Perceptually Weighted Peak Signal-to-Noise Ratio (XPSNR) for Video
Compression with Different Resolutions and Bit Depths," ITU Journal: ICT Discoveries,
vol. 3, no. 1, pp. 65 - 72, May 2020. <http://handle.itu.int/11.1002/pub/8153d78b-en>
When publishing the results of XPSNR assessments obtained using, e.g., this FFmpeg filter,
a reference to the above papers as a means of documentation is strongly encouraged. The
filter requires two input videos. The first input is considered a (usually not distorted)
reference source and is passed unchanged to the output, whereas the second input is a
(distorted) test signal. Except for the bit depth, these two video inputs must have the
same pixel format. In addition, for best performance, both compared input videos should be
in YCbCr color format.
The obtained overall XPSNR values mentioned above are printed through the logging system.
In case of input with multiple color planes, we suggest reporting of the minimum XPSNR
average.
The following parameter, which behaves like the one for the psnr filter, is accepted:
stats_file, f
If specified, the filter will use the named file to save the XPSNR value of each
individual frame and color plane. When the file name equals "-", that data is sent to
standard output.
This filter also supports the framesync options.
Examples
• XPSNR analysis of two 1080p HD videos, ref_source.yuv and test_video.yuv, both at 24
frames per second, with color format 4:2:0, bit depth 8, and output of a logfile named
"xpsnr.log":
ffmpeg -s 1920x1080 -framerate 24 -pix_fmt yuv420p -i ref_source.yuv -s 1920x1080 -framerate
24 -pix_fmt yuv420p -i test_video.yuv -lavfi xpsnr="stats_file=xpsnr.log" -f null -
• XPSNR analysis of two 2160p UHD videos, ref_source.yuv with bit depth 8 and
test_video.yuv with bit depth 10, both at 60 frames per second with color format
4:2:0, no logfile output:
ffmpeg -s 3840x2160 -framerate 60 -pix_fmt yuv420p -i ref_source.yuv -s 3840x2160 -framerate
60 -pix_fmt yuv420p10le -i test_video.yuv -lavfi xpsnr="stats_file=-" -f null -
xstack
Stack video inputs into custom layout.
All streams must be of same pixel format.
The filter accepts the following options:
inputs
Set number of input streams. Default is 2.
layout
Specify layout of inputs. This option requires the desired layout configuration to be
explicitly set by the user. This sets position of each video input in output. Each
input is separated by '|'. The first number represents the column, and the second
number represents the row. Numbers start at 0 and are separated by '_'. Optionally
one can use wX and hX, where X is video input from which to take width or height.
Multiple values can be used when separated by '+'. In such case values are summed
together.
Note that if inputs are of different sizes gaps may appear, as not all of the output
video frame will be filled. Similarly, videos can overlap each other if their position
doesn't leave enough space for the full frame of adjoining videos.
For 2 inputs, a default layout of "0_0|w0_0" (equivalent to "grid=2x1") is set. In all
other cases, a layout or a grid must be set by the user. Either "grid" or "layout" can
be specified at a time. Specifying both will result in an error.
grid
Specify a fixed size grid of inputs. This option is used to create a fixed size grid
of the input streams. Set the grid size in the form "COLUMNSxROWS". There must be
"ROWS * COLUMNS" input streams and they will be arranged as a grid with "ROWS" rows
and "COLUMNS" columns. When using this option, each input stream within a row must
have the same height and all the rows must have the same width.
If "grid" is set, then "inputs" option is ignored and is implicitly set to "ROWS *
COLUMNS".
For 2 inputs, a default grid of "2x1" (equivalent to "layout=0_0|w0_0") is set. In all
other cases, a layout or a grid must be set by the user. Either "grid" or "layout" can
be specified at a time. Specifying both will result in an error.
shortest
If set to 1, force the output to terminate when the shortest input terminates. Default
value is 0.
fill
If set to valid color, all unused pixels will be filled with that color. By default
fill is set to none, so it is disabled.
Examples
• Display 4 inputs into 2x2 grid.
Layout:
input1(0, 0) | input3(w0, 0)
input2(0, h0) | input4(w0, h0)
xstack=inputs=4:layout=0_0|0_h0|w0_0|w0_h0
Note that if inputs are of different sizes, gaps or overlaps may occur.
• Display 4 inputs into 1x4 grid.
Layout:
input1(0, 0)
input2(0, h0)
input3(0, h0+h1)
input4(0, h0+h1+h2)
xstack=inputs=4:layout=0_0|0_h0|0_h0+h1|0_h0+h1+h2
Note that if inputs are of different widths, unused space will appear.
• Display 9 inputs into 3x3 grid.
Layout:
input1(0, 0) | input4(w0, 0) | input7(w0+w3, 0)
input2(0, h0) | input5(w0, h0) | input8(w0+w3, h0)
input3(0, h0+h1) | input6(w0, h0+h1) | input9(w0+w3, h0+h1)
xstack=inputs=9:layout=0_0|0_h0|0_h0+h1|w0_0|w0_h0|w0_h0+h1|w0+w3_0|w0+w3_h0|w0+w3_h0+h1
Note that if inputs are of different sizes, gaps or overlaps may occur.
• Display 16 inputs into 4x4 grid.
Layout:
input1(0, 0) | input5(w0, 0) | input9 (w0+w4, 0) | input13(w0+w4+w8, 0)
input2(0, h0) | input6(w0, h0) | input10(w0+w4, h0) | input14(w0+w4+w8, h0)
input3(0, h0+h1) | input7(w0, h0+h1) | input11(w0+w4, h0+h1) | input15(w0+w4+w8, h0+h1)
input4(0, h0+h1+h2)| input8(w0, h0+h1+h2)| input12(w0+w4, h0+h1+h2)| input16(w0+w4+w8, h0+h1+h2)
xstack=inputs=16:layout=0_0|0_h0|0_h0+h1|0_h0+h1+h2|w0_0|w0_h0|w0_h0+h1|w0_h0+h1+h2|w0+w4_0|
w0+w4_h0|w0+w4_h0+h1|w0+w4_h0+h1+h2|w0+w4+w8_0|w0+w4+w8_h0|w0+w4+w8_h0+h1|w0+w4+w8_h0+h1+h2
Note that if inputs are of different sizes, gaps or overlaps may occur.
yadif
Deinterlace the input video ("yadif" means "yet another deinterlacing filter").
It accepts the following parameters:
mode
The interlacing mode to adopt. It accepts one of the following values:
0, send_frame
Output one frame for each frame.
1, send_field
Output one frame for each field.
2, send_frame_nospatial
Like "send_frame", but it skips the spatial interlacing check.
3, send_field_nospatial
Like "send_field", but it skips the spatial interlacing check.
The default value is "send_frame".
parity
The picture field parity assumed for the input interlaced video. It accepts one of the
following values:
0, tff
Assume the top field is first.
1, bff
Assume the bottom field is first.
-1, auto
Enable automatic detection of field parity.
The default value is "auto". If the interlacing is unknown or the decoder does not
export this information, top field first will be assumed.
deint
Specify which frames to deinterlace. Accepts one of the following values:
0, all
Deinterlace all frames.
1, interlaced
Only deinterlace frames marked as interlaced.
The default value is "all".
yadif_cuda
Deinterlace the input video using the yadif algorithm, but implemented in CUDA so that it
can work as part of a GPU accelerated pipeline with nvdec and/or nvenc.
It accepts the following parameters:
mode
The interlacing mode to adopt. It accepts one of the following values:
0, send_frame
Output one frame for each frame.
1, send_field
Output one frame for each field.
2, send_frame_nospatial
Like "send_frame", but it skips the spatial interlacing check.
3, send_field_nospatial
Like "send_field", but it skips the spatial interlacing check.
The default value is "send_frame".
parity
The picture field parity assumed for the input interlaced video. It accepts one of the
following values:
0, tff
Assume the top field is first.
1, bff
Assume the bottom field is first.
-1, auto
Enable automatic detection of field parity.
The default value is "auto". If the interlacing is unknown or the decoder does not
export this information, top field first will be assumed.
deint
Specify which frames to deinterlace. Accepts one of the following values:
0, all
Deinterlace all frames.
1, interlaced
Only deinterlace frames marked as interlaced.
The default value is "all".
yaepblur
Apply blur filter while preserving edges ("yaepblur" means "yet another edge preserving
blur filter"). The algorithm is described in "J. S. Lee, Digital image enhancement and
noise filtering by use of local statistics, IEEE Trans. Pattern Anal. Mach. Intell.
PAMI-2, 1980."
It accepts the following parameters:
radius, r
Set the window radius. Default value is 3.
planes, p
Set which planes to filter. Default is only the first plane.
sigma, s
Set blur strength. Default value is 128.
Commands
This filter supports same commands as options.
zoompan
Apply Zoom & Pan effect.
This filter accepts the following options:
zoom, z
Set the zoom expression. Range is 1-10. Default is 1.
x
y Set the x and y expression. Default is 0.
d Set the duration expression in number of frames. This sets for how many number of
frames effect will last for single input image. Default is 90.
s Set the output image size, default is 'hd720'.
fps Set the output frame rate, default is '25'.
Each expression can contain the following constants:
in_w, iw
Input width.
in_h, ih
Input height.
out_w, ow
Output width.
out_h, oh
Output height.
in Input frame count.
on Output frame count.
in_time, it
The input timestamp expressed in seconds. It's NAN if the input timestamp is unknown.
out_time, time, ot
The output timestamp expressed in seconds.
x
y Last calculated 'x' and 'y' position from 'x' and 'y' expression for current input
frame.
px
py 'x' and 'y' of last output frame of previous input frame or 0 when there was not yet
such frame (first input frame).
zoom
Last calculated zoom from 'z' expression for current input frame.
pzoom
Last calculated zoom of last output frame of previous input frame.
duration
Number of output frames for current input frame. Calculated from 'd' expression for
each input frame.
pduration
number of output frames created for previous input frame
a Rational number: input width / input height
sar sample aspect ratio
dar display aspect ratio
Examples
• Zoom in up to 1.5x and pan at same time to some spot near center of picture:
zoompan=z='min(zoom+0.0015,1.5)':d=700:x='if(gte(zoom,1.5),x,x+1/a)':y='if(gte(zoom,1.5),y,y+1)':s=640x360
• Zoom in up to 1.5x and pan always at center of picture:
zoompan=z='min(zoom+0.0015,1.5)':d=700:x='iw/2-(iw/zoom/2)':y='ih/2-(ih/zoom/2)'
• Same as above but without pausing:
zoompan=z='min(max(zoom,pzoom)+0.0015,1.5)':d=1:x='iw/2-(iw/zoom/2)':y='ih/2-(ih/zoom/2)'
• Zoom in 2x into center of picture only for the first second of the input video:
zoompan=z='if(between(in_time,0,1),2,1)':d=1:x='iw/2-(iw/zoom/2)':y='ih/2-(ih/zoom/2)'
zscale
Scale (resize) the input video, using the z.lib library:
<https://github.com/sekrit-twc/zimg>. To enable compilation of this filter, you need to
configure FFmpeg with "--enable-libzimg".
The zscale filter forces the output display aspect ratio to be the same as the input, by
changing the output sample aspect ratio.
If the input image format is different from the format requested by the next filter, the
zscale filter will convert the input to the requested format.
Options
The filter accepts the following options.
width, w
height, h
Set the output video dimension expression. Default value is the input dimension.
If the width or w value is 0, the input width is used for the output. If the height or
h value is 0, the input height is used for the output.
If one and only one of the values is -n with n >= 1, the zscale filter will use a
value that maintains the aspect ratio of the input image, calculated from the other
specified dimension. After that it will, however, make sure that the calculated
dimension is divisible by n and adjust the value if necessary.
If both values are -n with n >= 1, the behavior will be identical to both values being
set to 0 as previously detailed.
See below for the list of accepted constants for use in the dimension expression.
size, s
Set the video size. For the syntax of this option, check the "Video size" section in
the ffmpeg-utils manual.
dither, d
Set the dither type.
Possible values are:
none
ordered
random
error_diffusion
Default is none.
filter, f
Set the resize filter type.
Possible values are:
point
bilinear
bicubic
spline16
spline36
lanczos
Default is bilinear.
range, r
Set the color range.
Possible values are:
input
limited
full
Default is same as input.
primaries, p
Set the color primaries.
Possible values are:
input
709
unspecified
170m
240m
2020
Default is same as input.
transfer, t
Set the transfer characteristics.
Possible values are:
input
709
unspecified
601
linear
2020_10
2020_12
smpte2084
iec61966-2-1
arib-std-b67
Default is same as input.
matrix, m
Set the colorspace matrix.
Possible value are:
input
709
unspecified
470bg
170m
2020_ncl
2020_cl
Default is same as input.
rangein, rin
Set the input color range.
Possible values are:
input
limited
full
Default is same as input.
primariesin, pin
Set the input color primaries.
Possible values are:
input
709
unspecified
170m
240m
2020
Default is same as input.
transferin, tin
Set the input transfer characteristics.
Possible values are:
input
709
unspecified
601
linear
2020_10
2020_12
Default is same as input.
matrixin, min
Set the input colorspace matrix.
Possible value are:
input
709
unspecified
470bg
170m
2020_ncl
2020_cl
chromal, c
Set the output chroma location.
Possible values are:
input
left
center
topleft
top
bottomleft
bottom
chromalin, cin
Set the input chroma location.
Possible values are:
input
left
center
topleft
top
bottomleft
bottom
npl Set the nominal peak luminance.
param_a
Parameter A for scaling filters. Parameter "b" for bicubic, and the number of filter
taps for lanczos.
param_b
Parameter B for scaling filters. Parameter "c" for bicubic.
The values of the w and h options are expressions containing the following constants:
in_w
in_h
The input width and height
iw
ih These are the same as in_w and in_h.
out_w
out_h
The output (scaled) width and height
ow
oh These are the same as out_w and out_h
a The same as iw / ih
sar input sample aspect ratio
dar The input display aspect ratio. Calculated from "(iw / ih) * sar".
hsub
vsub
horizontal and vertical input chroma subsample values. For example for the pixel
format "yuv422p" hsub is 2 and vsub is 1.
ohsub
ovsub
horizontal and vertical output chroma subsample values. For example for the pixel
format "yuv422p" hsub is 2 and vsub is 1.
Commands
This filter supports the following commands:
width, w
height, h
Set the output video dimension expression. The command accepts the same syntax of the
corresponding option.
If the specified expression is not valid, it is kept at its current value.
OPENCL VIDEO FILTERS
Below is a description of the currently available OpenCL video filters.
To enable compilation of these filters you need to configure FFmpeg with
"--enable-opencl".
Running OpenCL filters requires you to initialize a hardware device and to pass that
device to all filters in any filter graph.
-init_hw_device opencl[=name][:device[,key=value...]]
Initialise a new hardware device of type opencl called name, using the given device
parameters.
-filter_hw_device name
Pass the hardware device called name to all filters in any filter graph.
For more detailed information see
<https://www.ffmpeg.org/ffmpeg.html#Advanced-Video-options>
• Example of choosing the first device on the second platform and running avgblur_opencl
filter with default parameters on it.
-init_hw_device opencl=gpu:1.0 -filter_hw_device gpu -i INPUT -vf "hwupload, avgblur_opencl, hwdownload" OUTPUT
Since OpenCL filters are not able to access frame data in normal memory, all frame data
needs to be uploaded(hwupload) to hardware surfaces connected to the appropriate device
before being used and then downloaded(hwdownload) back to normal memory. Note that
hwupload will upload to a surface with the same layout as the software frame, so it may be
necessary to add a format filter immediately before to get the input into the right format
and hwdownload does not support all formats on the output - it may be necessary to insert
an additional format filter immediately following in the graph to get the output in a
supported format.
avgblur_opencl
Apply average blur filter.
The filter accepts the following options:
sizeX
Set horizontal radius size. Range is "[1, 1024]" and default value is 1.
planes
Set which planes to filter. Default value is 0xf, by which all planes are processed.
sizeY
Set vertical radius size. Range is "[1, 1024]" and default value is 0. If zero,
"sizeX" value will be used.
Example
• Apply average blur filter with horizontal and vertical size of 3, setting each pixel
of the output to the average value of the 7x7 region centered on it in the input. For
pixels on the edges of the image, the region does not extend beyond the image
boundaries, and so out-of-range coordinates are not used in the calculations.
-i INPUT -vf "hwupload, avgblur_opencl=3, hwdownload" OUTPUT
boxblur_opencl
Apply a boxblur algorithm to the input video.
It accepts the following parameters:
luma_radius, lr
luma_power, lp
chroma_radius, cr
chroma_power, cp
alpha_radius, ar
alpha_power, ap
A description of the accepted options follows.
luma_radius, lr
chroma_radius, cr
alpha_radius, ar
Set an expression for the box radius in pixels used for blurring the corresponding
input plane.
The radius value must be a non-negative number, and must not be greater than the value
of the expression "min(w,h)/2" for the luma and alpha planes, and of "min(cw,ch)/2"
for the chroma planes.
Default value for luma_radius is "2". If not specified, chroma_radius and alpha_radius
default to the corresponding value set for luma_radius.
The expressions can contain the following constants:
w
h The input width and height in pixels.
cw
ch The input chroma image width and height in pixels.
hsub
vsub
The horizontal and vertical chroma subsample values. For example, for the pixel
format "yuv422p", hsub is 2 and vsub is 1.
luma_power, lp
chroma_power, cp
alpha_power, ap
Specify how many times the boxblur filter is applied to the corresponding plane.
Default value for luma_power is 2. If not specified, chroma_power and alpha_power
default to the corresponding value set for luma_power.
A value of 0 will disable the effect.
Examples
Apply boxblur filter, setting each pixel of the output to the average value of box-
radiuses luma_radius, chroma_radius, alpha_radius for each plane respectively. The filter
will apply luma_power, chroma_power, alpha_power times onto the corresponding plane. For
pixels on the edges of the image, the radius does not extend beyond the image boundaries,
and so out-of-range coordinates are not used in the calculations.
• Apply a boxblur filter with the luma, chroma, and alpha radius set to 2 and luma,
chroma, and alpha power set to 3. The filter will run 3 times with box-radius set to 2
for every plane of the image.
-i INPUT -vf "hwupload, boxblur_opencl=luma_radius=2:luma_power=3, hwdownload" OUTPUT
-i INPUT -vf "hwupload, boxblur_opencl=2:3, hwdownload" OUTPUT
• Apply a boxblur filter with luma radius set to 2, luma_power to 1, chroma_radius to 4,
chroma_power to 5, alpha_radius to 3 and alpha_power to 7.
For the luma plane, a 2x2 box radius will be run once.
For the chroma plane, a 4x4 box radius will be run 5 times.
For the alpha plane, a 3x3 box radius will be run 7 times.
-i INPUT -vf "hwupload, boxblur_opencl=2:1:4:5:3:7, hwdownload" OUTPUT
colorkey_opencl
RGB colorspace color keying.
The filter accepts the following options:
color
The color which will be replaced with transparency.
similarity
Similarity percentage with the key color.
0.01 matches only the exact key color, while 1.0 matches everything.
blend
Blend percentage.
0.0 makes pixels either fully transparent, or not transparent at all.
Higher values result in semi-transparent pixels, with a higher transparency the more
similar the pixels color is to the key color.
Examples
• Make every semi-green pixel in the input transparent with some slight blending:
-i INPUT -vf "hwupload, colorkey_opencl=green:0.3:0.1, hwdownload" OUTPUT
convolution_opencl
Apply convolution of 3x3, 5x5, 7x7 matrix.
The filter accepts the following options:
0m
1m
2m
3m Set matrix for each plane. Matrix is sequence of 9, 25 or 49 signed numbers. Default
value for each plane is "0 0 0 0 1 0 0 0 0".
0rdiv
1rdiv
2rdiv
3rdiv
Set multiplier for calculated value for each plane. If unset or 0, it will be sum of
all matrix elements. The option value must be a float number greater or equal to 0.0.
Default value is 1.0.
0bias
1bias
2bias
3bias
Set bias for each plane. This value is added to the result of the multiplication.
Useful for making the overall image brighter or darker. The option value must be a
float number greater or equal to 0.0. Default value is 0.0.
Examples
• Apply sharpen:
-i INPUT -vf "hwupload, convolution_opencl=0 -1 0 -1 5 -1 0 -1 0:0 -1 0 -1 5 -1 0 -1 0:0 -1 0 -1 5 -1 0 -1 0:0 -1 0 -1 5 -1 0 -1 0, hwdownload" OUTPUT
• Apply blur:
-i INPUT -vf "hwupload, convolution_opencl=1 1 1 1 1 1 1 1 1:1 1 1 1 1 1 1 1 1:1 1 1 1 1 1 1 1 1:1 1 1 1 1 1 1 1 1:1/9:1/9:1/9:1/9, hwdownload" OUTPUT
• Apply edge enhance:
-i INPUT -vf "hwupload, convolution_opencl=0 0 0 -1 1 0 0 0 0:0 0 0 -1 1 0 0 0 0:0 0 0 -1 1 0 0 0 0:0 0 0 -1 1 0 0 0 0:5:1:1:1:0:128:128:128, hwdownload" OUTPUT
• Apply edge detect:
-i INPUT -vf "hwupload, convolution_opencl=0 1 0 1 -4 1 0 1 0:0 1 0 1 -4 1 0 1 0:0 1 0 1 -4 1 0 1 0:0 1 0 1 -4 1 0 1 0:5:5:5:1:0:128:128:128, hwdownload" OUTPUT
• Apply laplacian edge detector which includes diagonals:
-i INPUT -vf "hwupload, convolution_opencl=1 1 1 1 -8 1 1 1 1:1 1 1 1 -8 1 1 1 1:1 1 1 1 -8 1 1 1 1:1 1 1 1 -8 1 1 1 1:5:5:5:1:0:128:128:0, hwdownload" OUTPUT
• Apply emboss:
-i INPUT -vf "hwupload, convolution_opencl=-2 -1 0 -1 1 1 0 1 2:-2 -1 0 -1 1 1 0 1 2:-2 -1 0 -1 1 1 0 1 2:-2 -1 0 -1 1 1 0 1 2, hwdownload" OUTPUT
erosion_opencl
Apply erosion effect to the video.
This filter replaces the pixel by the local(3x3) minimum.
It accepts the following options:
threshold0
threshold1
threshold2
threshold3
Limit the maximum change for each plane. Range is "[0, 65535]" and default value is
65535. If 0, plane will remain unchanged.
coordinates
Flag which specifies the pixel to refer to. Range is "[0, 255]" and default value is
255, i.e. all eight pixels are used.
Flags to local 3x3 coordinates region centered on "x":
1 2 3
4 x 5
6 7 8
Example
• Apply erosion filter with threshold0 set to 30, threshold1 set 40, threshold2 set to
50 and coordinates set to 231, setting each pixel of the output to the local minimum
between pixels: 1, 2, 3, 6, 7, 8 of the 3x3 region centered on it in the input. If the
difference between input pixel and local minimum is more then threshold of the
corresponding plane, output pixel will be set to input pixel - threshold of
corresponding plane.
-i INPUT -vf "hwupload, erosion_opencl=30:40:50:coordinates=231, hwdownload" OUTPUT
deshake_opencl
Feature-point based video stabilization filter.
The filter accepts the following options:
tripod
Simulates a tripod by preventing any camera movement whatsoever from the original
frame. Defaults to 0.
debug
Whether or not additional debug info should be displayed, both in the processed output
and in the console.
Note that in order to see console debug output you will also need to pass "-v verbose"
to ffmpeg.
Viewing point matches in the output video is only supported for RGB input.
Defaults to 0.
adaptive_crop
Whether or not to do a tiny bit of cropping at the borders to cut down on the amount
of mirrored pixels.
Defaults to 1.
refine_features
Whether or not feature points should be refined at a sub-pixel level.
This can be turned off for a slight performance gain at the cost of precision.
Defaults to 1.
smooth_strength
The strength of the smoothing applied to the camera path from 0.0 to 1.0.
1.0 is the maximum smoothing strength while values less than that result in less
smoothing.
0.0 causes the filter to adaptively choose a smoothing strength on a per-frame basis.
Defaults to 0.0.
smooth_window_multiplier
Controls the size of the smoothing window (the number of frames buffered to determine
motion information from).
The size of the smoothing window is determined by multiplying the framerate of the
video by this number.
Acceptable values range from 0.1 to 10.0.
Larger values increase the amount of motion data available for determining how to
smooth the camera path, potentially improving smoothness, but also increase latency
and memory usage.
Defaults to 2.0.
Examples
• Stabilize a video with a fixed, medium smoothing strength:
-i INPUT -vf "hwupload, deshake_opencl=smooth_strength=0.5, hwdownload" OUTPUT
• Stabilize a video with debugging (both in console and in rendered video):
-i INPUT -filter_complex "[0:v]format=rgba, hwupload, deshake_opencl=debug=1, hwdownload, format=rgba, format=yuv420p" -v verbose OUTPUT
dilation_opencl
Apply dilation effect to the video.
This filter replaces the pixel by the local(3x3) maximum.
It accepts the following options:
threshold0
threshold1
threshold2
threshold3
Limit the maximum change for each plane. Range is "[0, 65535]" and default value is
65535. If 0, plane will remain unchanged.
coordinates
Flag which specifies the pixel to refer to. Range is "[0, 255]" and default value is
255, i.e. all eight pixels are used.
Flags to local 3x3 coordinates region centered on "x":
1 2 3
4 x 5
6 7 8
Example
• Apply dilation filter with threshold0 set to 30, threshold1 set 40, threshold2 set to
50 and coordinates set to 231, setting each pixel of the output to the local maximum
between pixels: 1, 2, 3, 6, 7, 8 of the 3x3 region centered on it in the input. If the
difference between input pixel and local maximum is more then threshold of the
corresponding plane, output pixel will be set to input pixel + threshold of
corresponding plane.
-i INPUT -vf "hwupload, dilation_opencl=30:40:50:coordinates=231, hwdownload" OUTPUT
nlmeans_opencl
Non-local Means denoise filter through OpenCL, this filter accepts same options as
nlmeans.
overlay_opencl
Overlay one video on top of another.
It takes two inputs and has one output. The first input is the "main" video on which the
second input is overlaid. This filter requires same memory layout for all the inputs. So,
format conversion may be needed.
The filter accepts the following options:
x Set the x coordinate of the overlaid video on the main video. Default value is 0.
y Set the y coordinate of the overlaid video on the main video. Default value is 0.
Examples
• Overlay an image LOGO at the top-left corner of the INPUT video. Both inputs are
yuv420p format.
-i INPUT -i LOGO -filter_complex "[0:v]hwupload[a], [1:v]format=yuv420p, hwupload[b], [a][b]overlay_opencl, hwdownload" OUTPUT
• The inputs have same memory layout for color channels , the overlay has additional
alpha plane, like INPUT is yuv420p, and the LOGO is yuva420p.
-i INPUT -i LOGO -filter_complex "[0:v]hwupload[a], [1:v]format=yuva420p, hwupload[b], [a][b]overlay_opencl, hwdownload" OUTPUT
pad_opencl
Add paddings to the input image, and place the original input at the provided x, y
coordinates.
It accepts the following options:
width, w
height, h
Specify an expression for the size of the output image with the paddings added. If the
value for width or height is 0, the corresponding input size is used for the output.
The width expression can reference the value set by the height expression, and vice
versa.
The default value of width and height is 0.
x
y Specify the offsets to place the input image at within the padded area, with respect
to the top/left border of the output image.
The x expression can reference the value set by the y expression, and vice versa.
The default value of x and y is 0.
If x or y evaluate to a negative number, they'll be changed so the input image is
centered on the padded area.
color
Specify the color of the padded area. For the syntax of this option, check the "Color"
section in the ffmpeg-utils manual.
aspect
Pad to an aspect instead to a resolution.
The value for the width, height, x, and y options are expressions containing the following
constants:
in_w
in_h
The input video width and height.
iw
ih These are the same as in_w and in_h.
out_w
out_h
The output width and height (the size of the padded area), as specified by the width
and height expressions.
ow
oh These are the same as out_w and out_h.
x
y The x and y offsets as specified by the x and y expressions, or NAN if not yet
specified.
a same as iw / ih
sar input sample aspect ratio
dar input display aspect ratio, it is the same as (iw / ih) * sar
prewitt_opencl
Apply the Prewitt operator (<https://en.wikipedia.org/wiki/Prewitt_operator>) to input
video stream.
The filter accepts the following option:
planes
Set which planes to filter. Default value is 0xf, by which all planes are processed.
scale
Set value which will be multiplied with filtered result. Range is "[0.0, 65535]" and
default value is 1.0.
delta
Set value which will be added to filtered result. Range is "[-65535, 65535]" and
default value is 0.0.
Example
• Apply the Prewitt operator with scale set to 2 and delta set to 10.
-i INPUT -vf "hwupload, prewitt_opencl=scale=2:delta=10, hwdownload" OUTPUT
program_opencl
Filter video using an OpenCL program.
source
OpenCL program source file.
kernel
Kernel name in program.
inputs
Number of inputs to the filter. Defaults to 1.
size, s
Size of output frames. Defaults to the same as the first input.
The "program_opencl" filter also supports the framesync options.
The program source file must contain a kernel function with the given name, which will be
run once for each plane of the output. Each run on a plane gets enqueued as a separate 2D
global NDRange with one work-item for each pixel to be generated. The global ID offset
for each work-item is therefore the coordinates of a pixel in the destination image.
The kernel function needs to take the following arguments:
• Destination image, __write_only image2d_t.
This image will become the output; the kernel should write all of it.
• Frame index, unsigned int.
This is a counter starting from zero and increasing by one for each frame.
• Source images, __read_only image2d_t.
These are the most recent images on each input. The kernel may read from them to
generate the output, but they can't be written to.
Example programs:
• Copy the input to the output (output must be the same size as the input).
__kernel void copy(__write_only image2d_t destination,
unsigned int index,
__read_only image2d_t source)
{
const sampler_t sampler = CLK_NORMALIZED_COORDS_FALSE;
int2 location = (int2)(get_global_id(0), get_global_id(1));
float4 value = read_imagef(source, sampler, location);
write_imagef(destination, location, value);
}
• Apply a simple transformation, rotating the input by an amount increasing with the
index counter. Pixel values are linearly interpolated by the sampler, and the output
need not have the same dimensions as the input.
__kernel void rotate_image(__write_only image2d_t dst,
unsigned int index,
__read_only image2d_t src)
{
const sampler_t sampler = (CLK_NORMALIZED_COORDS_FALSE |
CLK_FILTER_LINEAR);
float angle = (float)index / 100.0f;
float2 dst_dim = convert_float2(get_image_dim(dst));
float2 src_dim = convert_float2(get_image_dim(src));
float2 dst_cen = dst_dim / 2.0f;
float2 src_cen = src_dim / 2.0f;
int2 dst_loc = (int2)(get_global_id(0), get_global_id(1));
float2 dst_pos = convert_float2(dst_loc) - dst_cen;
float2 src_pos = {
cos(angle) * dst_pos.x - sin(angle) * dst_pos.y,
sin(angle) * dst_pos.x + cos(angle) * dst_pos.y
};
src_pos = src_pos * src_dim / dst_dim;
float2 src_loc = src_pos + src_cen;
if (src_loc.x < 0.0f || src_loc.y < 0.0f ||
src_loc.x > src_dim.x || src_loc.y > src_dim.y)
write_imagef(dst, dst_loc, 0.5f);
else
write_imagef(dst, dst_loc, read_imagef(src, sampler, src_loc));
}
• Blend two inputs together, with the amount of each input used varying with the index
counter.
__kernel void blend_images(__write_only image2d_t dst,
unsigned int index,
__read_only image2d_t src1,
__read_only image2d_t src2)
{
const sampler_t sampler = (CLK_NORMALIZED_COORDS_FALSE |
CLK_FILTER_LINEAR);
float blend = (cos((float)index / 50.0f) + 1.0f) / 2.0f;
int2 dst_loc = (int2)(get_global_id(0), get_global_id(1));
int2 src1_loc = dst_loc * get_image_dim(src1) / get_image_dim(dst);
int2 src2_loc = dst_loc * get_image_dim(src2) / get_image_dim(dst);
float4 val1 = read_imagef(src1, sampler, src1_loc);
float4 val2 = read_imagef(src2, sampler, src2_loc);
write_imagef(dst, dst_loc, val1 * blend + val2 * (1.0f - blend));
}
remap_opencl
Remap pixels using 2nd: Xmap and 3rd: Ymap input video stream.
Destination pixel at position (X, Y) will be picked from source (x, y) position where x =
Xmap(X, Y) and y = Ymap(X, Y). If mapping values are out of range, zero value for pixel
will be used for destination pixel.
Xmap and Ymap input video streams must be of same dimensions. Output video stream will
have Xmap/Ymap video stream dimensions. Xmap and Ymap input video streams are 32bit float
pixel format, single channel.
interp
Specify interpolation used for remapping of pixels. Allowed values are "near" and
"linear". Default value is "linear".
fill
Specify the color of the unmapped pixels. For the syntax of this option, check the
"Color" section in the ffmpeg-utils manual. Default color is "black".
roberts_opencl
Apply the Roberts cross operator (<https://en.wikipedia.org/wiki/Roberts_cross>) to input
video stream.
The filter accepts the following option:
planes
Set which planes to filter. Default value is 0xf, by which all planes are processed.
scale
Set value which will be multiplied with filtered result. Range is "[0.0, 65535]" and
default value is 1.0.
delta
Set value which will be added to filtered result. Range is "[-65535, 65535]" and
default value is 0.0.
Example
• Apply the Roberts cross operator with scale set to 2 and delta set to 10
-i INPUT -vf "hwupload, roberts_opencl=scale=2:delta=10, hwdownload" OUTPUT
sobel_opencl
Apply the Sobel operator (<https://en.wikipedia.org/wiki/Sobel_operator>) to input video
stream.
The filter accepts the following option:
planes
Set which planes to filter. Default value is 0xf, by which all planes are processed.
scale
Set value which will be multiplied with filtered result. Range is "[0.0, 65535]" and
default value is 1.0.
delta
Set value which will be added to filtered result. Range is "[-65535, 65535]" and
default value is 0.0.
Example
• Apply sobel operator with scale set to 2 and delta set to 10
-i INPUT -vf "hwupload, sobel_opencl=scale=2:delta=10, hwdownload" OUTPUT
tonemap_opencl
Perform HDR(PQ/HLG) to SDR conversion with tone-mapping.
It accepts the following parameters:
tonemap
Specify the tone-mapping operator to be used. Same as tonemap option in tonemap.
param
Tune the tone mapping algorithm. same as param option in tonemap.
desat
Apply desaturation for highlights that exceed this level of brightness. The higher the
parameter, the more color information will be preserved. This setting helps prevent
unnaturally blown-out colors for super-highlights, by (smoothly) turning into white
instead. This makes images feel more natural, at the cost of reducing information
about out-of-range colors.
The default value is 0.5, and the algorithm here is a little different from the cpu
version tonemap currently. A setting of 0.0 disables this option.
threshold
The tonemapping algorithm parameters is fine-tuned per each scene. And a threshold is
used to detect whether the scene has changed or not. If the distance between the
current frame average brightness and the current running average exceeds a threshold
value, we would re-calculate scene average and peak brightness. The default value is
0.2.
format
Specify the output pixel format.
Currently supported formats are:
p010
nv12
range, r
Set the output color range.
Possible values are:
tv/mpeg
pc/jpeg
Default is same as input.
primaries, p
Set the output color primaries.
Possible values are:
bt709
bt2020
Default is same as input.
transfer, t
Set the output transfer characteristics.
Possible values are:
bt709
bt2020
Default is bt709.
matrix, m
Set the output colorspace matrix.
Possible value are:
bt709
bt2020
Default is same as input.
Example
• Convert HDR(PQ/HLG) video to bt2020-transfer-characteristic p010 format using linear
operator.
-i INPUT -vf "format=p010,hwupload,tonemap_opencl=t=bt2020:tonemap=linear:format=p010,hwdownload,format=p010" OUTPUT
unsharp_opencl
Sharpen or blur the input video.
It accepts the following parameters:
luma_msize_x, lx
Set the luma matrix horizontal size. Range is "[1, 23]" and default value is 5.
luma_msize_y, ly
Set the luma matrix vertical size. Range is "[1, 23]" and default value is 5.
luma_amount, la
Set the luma effect strength. Range is "[-10, 10]" and default value is 1.0.
Negative values will blur the input video, while positive values will sharpen it, a
value of zero will disable the effect.
chroma_msize_x, cx
Set the chroma matrix horizontal size. Range is "[1, 23]" and default value is 5.
chroma_msize_y, cy
Set the chroma matrix vertical size. Range is "[1, 23]" and default value is 5.
chroma_amount, ca
Set the chroma effect strength. Range is "[-10, 10]" and default value is 0.0.
Negative values will blur the input video, while positive values will sharpen it, a
value of zero will disable the effect.
All parameters are optional and default to the equivalent of the string '5:5:1.0:5:5:0.0'.
Examples
• Apply strong luma sharpen effect:
-i INPUT -vf "hwupload, unsharp_opencl=luma_msize_x=7:luma_msize_y=7:luma_amount=2.5, hwdownload" OUTPUT
• Apply a strong blur of both luma and chroma parameters:
-i INPUT -vf "hwupload, unsharp_opencl=7:7:-2:7:7:-2, hwdownload" OUTPUT
xfade_opencl
Cross fade two videos with custom transition effect by using OpenCL.
It accepts the following options:
transition
Set one of possible transition effects.
custom
Select custom transition effect, the actual transition description will be picked
from source and kernel options.
fade
wipeleft
wiperight
wipeup
wipedown
slideleft
slideright
slideup
slidedown
Default transition is fade.
source
OpenCL program source file for custom transition.
kernel
Set name of kernel to use for custom transition from program source file.
duration
Set duration of video transition.
offset
Set time of start of transition relative to first video.
The program source file must contain a kernel function with the given name, which will be
run once for each plane of the output. Each run on a plane gets enqueued as a separate 2D
global NDRange with one work-item for each pixel to be generated. The global ID offset
for each work-item is therefore the coordinates of a pixel in the destination image.
The kernel function needs to take the following arguments:
• Destination image, __write_only image2d_t.
This image will become the output; the kernel should write all of it.
• First Source image, __read_only image2d_t. Second Source image, __read_only
image2d_t.
These are the most recent images on each input. The kernel may read from them to
generate the output, but they can't be written to.
• Transition progress, float. This value is always between 0 and 1 inclusive.
Example programs:
• Apply dots curtain transition effect:
__kernel void blend_images(__write_only image2d_t dst,
__read_only image2d_t src1,
__read_only image2d_t src2,
float progress)
{
const sampler_t sampler = (CLK_NORMALIZED_COORDS_FALSE |
CLK_FILTER_LINEAR);
int2 p = (int2)(get_global_id(0), get_global_id(1));
float2 rp = (float2)(get_global_id(0), get_global_id(1));
float2 dim = (float2)(get_image_dim(src1).x, get_image_dim(src1).y);
rp = rp / dim;
float2 dots = (float2)(20.0, 20.0);
float2 center = (float2)(0,0);
float2 unused;
float4 val1 = read_imagef(src1, sampler, p);
float4 val2 = read_imagef(src2, sampler, p);
bool next = distance(fract(rp * dots, &unused), (float2)(0.5, 0.5)) < (progress / distance(rp, center));
write_imagef(dst, p, next ? val1 : val2);
}
VAAPI VIDEO FILTERS
VAAPI Video filters are usually used with VAAPI decoder and VAAPI encoder. Below is a
description of VAAPI video filters.
To enable compilation of these filters you need to configure FFmpeg with "--enable-vaapi".
To use vaapi filters, you need to setup the vaapi device correctly. For more information,
please read <https://trac.ffmpeg.org/wiki/Hardware/VAAPI>
overlay_vaapi
Overlay one video on the top of another.
It takes two inputs and has one output. The first input is the "main" video on which the
second input is overlaid.
The filter accepts the following options:
x
y Set expressions for the x and y coordinates of the overlaid video on the main video.
Default value is "0" for both expressions.
w
h Set expressions for the width and height the overlaid video on the main video.
Default values are 'overlay_iw' for 'w' and 'overlay_ih*w/overlay_iw' for 'h'.
The expressions can contain the following parameters:
main_w, W
main_h, H
The main input width and height.
overlay_iw
overlay_ih
The overlay input width and height.
overlay_w, w
overlay_h, h
The overlay output width and height.
overlay_x, x
overlay_y, y
Position of the overlay layer inside of main
alpha
Set transparency of overlaid video. Allowed range is 0.0 to 1.0. Higher value means
lower transparency. Default value is 1.0.
eof_action
See framesync.
shortest
See framesync.
repeatlast
See framesync.
This filter also supports the framesync options.
Examples
• Overlay an image LOGO at the top-left corner of the INPUT video. Both inputs for this
filter are yuv420p format.
-i INPUT -i LOGO -filter_complex "[0:v]hwupload[a], [1:v]format=yuv420p, hwupload[b], [a][b]overlay_vaapi" OUTPUT
• Overlay an image LOGO at the offset (200, 100) from the top-left corner of the INPUT
video. The inputs have same memory layout for color channels, the overlay has
additional alpha plane, like INPUT is yuv420p, and the LOGO is yuva420p.
-i INPUT -i LOGO -filter_complex "[0:v]hwupload[a], [1:v]format=yuva420p, hwupload[b], [a][b]overlay_vaapi=x=200:y=100:w=400:h=300:alpha=1.0, hwdownload, format=nv12" OUTPUT
tonemap_vaapi
Perform HDR-to-SDR or HDR-to-HDR tone-mapping. It currently only accepts HDR10 as input.
It accepts the following parameters:
format
Specify the output pixel format.
Default is nv12 for HDR-to-SDR tone-mapping and p010 for HDR-to-HDR tone-mapping.
primaries, p
Set the output color primaries.
Default is bt709 for HDR-to-SDR tone-mapping and same as input for HDR-to-HDR tone-
mapping.
transfer, t
Set the output transfer characteristics.
Default is bt709 for HDR-to-SDR tone-mapping and same as input for HDR-to-HDR tone-
mapping.
matrix, m
Set the output colorspace matrix.
Default is bt709 for HDR-to-SDR tone-mapping and same as input for HDR-to-HDR tone-
mapping.
display
Set the output mastering display colour volume. It is given by a '|'-separated list of
two values, two values are space separated. It set display primaries x & y in G, B, R
order, then white point x & y, the nominal minimum & maximum display luminances.
HDR-to-HDR tone-mapping will be performed when this option is set.
light
Set the output content light level information. It accepts 2 space-separated values,
the first input is the maximum light level and the second input is the maximum average
light level.
It is ignored for HDR-to-SDR tone-mapping, and optional for HDR-to-HDR tone-mapping.
Example
• Convert HDR(HDR10) video to bt2020-transfer-characteristic p010 format
tonemap_vaapi=format=p010:t=bt2020-10
• Convert HDR video to HDR video
tonemap_vaapi=display=7500\ 3000|34000\ 16000|13250\ 34500|15635\ 16450|500\ 10000000
hstack_vaapi
Stack input videos horizontally.
This is the VA-API variant of the hstack filter, each input stream may have different
height, this filter will scale down/up each input stream while keeping the original
aspect.
It accepts the following options:
inputs
See hstack.
shortest
See hstack.
height
Set height of output. If set to 0, this filter will set height of output to height of
the first input stream. Default value is 0.
vstack_vaapi
Stack input videos vertically.
This is the VA-API variant of the vstack filter, each input stream may have different
width, this filter will scale down/up each input stream while keeping the original aspect.
It accepts the following options:
inputs
See vstack.
shortest
See vstack.
width
Set width of output. If set to 0, this filter will set width of output to width of the
first input stream. Default value is 0.
xstack_vaapi
Stack video inputs into custom layout.
This is the VA-API variant of the xstack filter, each input stream may have different
size, this filter will scale down/up each input stream to the given output size, or the
size of the first input stream.
It accepts the following options:
inputs
See xstack.
shortest
See xstack.
layout
See xstack. Moreover, this permits the user to supply output size for each input
stream.
xstack_vaapi=inputs=4:layout=0_0_1920x1080|0_h0_1920x1080|w0_0_1920x1080|w0_h0_1920x1080
grid
See xstack.
grid_tile_size
Set output size for each input stream when grid is set. If this option is not set,
this filter will set output size by default to the size of the first input stream. For
the syntax of this option, check the "Video size" section in the ffmpeg-utils manual.
fill
See xstack.
pad_vaapi
Add paddings to the input image, and place the original input at the provided x, y
coordinates.
It accepts the following options:
width, w
height, h
Specify an expression for the size of the output image with the paddings added. If the
value for width or height is 0, the corresponding input size is used for the output.
The width expression can reference the value set by the height expression, and vice
versa.
The default value of width and height is 0.
x
y Specify the offsets to place the input image at within the padded area, with respect
to the top/left border of the output image.
The x expression can reference the value set by the y expression, and vice versa.
The default value of x and y is 0.
If x or y evaluate to a negative number, they'll be changed so the input image is
centered on the padded area.
color
Specify the color of the padded area. For the syntax of this option, check the "Color"
section in the ffmpeg-utils manual.
aspect
Pad to an aspect instead to a resolution.
The value for the width, height, x, and y options are expressions containing the following
constants:
in_w
in_h
The input video width and height.
iw
ih These are the same as in_w and in_h.
out_w
out_h
The output width and height (the size of the padded area), as specified by the width
and height expressions.
ow
oh These are the same as out_w and out_h.
x
y The x and y offsets as specified by the x and y expressions, or NAN if not yet
specified.
a same as iw / ih
sar input sample aspect ratio
dar input display aspect ratio, it is the same as (iw / ih) * sar
drawbox_vaapi
Draw a colored box on the input image.
It accepts the following parameters:
x
y The expressions which specify the top left corner coordinates of the box. It defaults
to 0.
width, w
height, h
The expressions which specify the width and height of the box; if 0 they are
interpreted as the input width and height. It defaults to 0.
color, c
Specify the color of the box to write. For the general syntax of this option, check
the "Color" section in the ffmpeg-utils manual.
thickness, t
The expression which sets the thickness of the box edge. A value of "fill" will
create a filled box. Default value is 3.
See below for the list of accepted constants.
replace
With value 1, the pixels of the painted box will overwrite the video's color and alpha
pixels. Default is 0, which composites the box onto the input video.
The parameters for x, y, w and h and t are expressions containing the following constants:
in_h, ih
in_w, iw
The input width and height.
x
y The x and y offset coordinates where the box is drawn.
w
h The width and height of the drawn box.
t The thickness of the drawn box.
Examples
• Draw a black box around the edge of the input image:
drawbox
• Draw a box with color red and an opacity of 50%:
drawbox=10:20:200:60:red@0.5
The previous example can be specified as:
drawbox=x=10:y=20:w=200:h=60:color=red@0.5
• Fill the box with pink color:
drawbox=x=10:y=10:w=100:h=100:color=pink@0.5:t=fill
• Draw a 2-pixel red 2.40:1 mask:
drawbox=x=-t:y=0.5*(ih-iw/2.4)-t:w=iw+t*2:h=iw/2.4+t*2:t=2:c=red
VULKAN VIDEO FILTERS
Below is a description of the currently available Vulkan video filters.
To enable compilation of these filters you need to configure FFmpeg with "--enable-vulkan"
and either "--enable-libglslang" or "--enable-libshaderc".
Running Vulkan filters requires you to initialize a hardware device and to pass that
device to all filters in any filter graph.
-init_hw_device vulkan[=name][:device[,key=value...]]
Initialise a new hardware device of type vulkan called name, using the given device
parameters and options in key=value. The following options are supported:
debug
Switches validation layers on if set to 1.
linear_images
Allocates linear images. Does not apply to decoding.
disable_multiplane
Disables multiplane images. Does not apply to decoding.
-filter_hw_device name
Pass the hardware device called name to all filters in any filter graph.
For more detailed information see
<https://www.ffmpeg.org/ffmpeg.html#Advanced-Video-options>
• Example of choosing the first device and running nlmeans_vulkan filter with default
parameters on it.
-init_hw_device vulkan=vk:0 -filter_hw_device vk -i INPUT -vf "hwupload,nlmeans_vulkan,hwdownload" OUTPUT
As Vulkan filters are not able to access frame data in normal memory, all frame data needs
to be uploaded (hwupload) to hardware surfaces connected to the appropriate device before
being used and then downloaded (hwdownload) back to normal memory. Note that hwupload will
upload to a frame with the same layout as the software frame, so it may be necessary to
add a format filter immediately before to get the input into the right format and
hwdownload does not support all formats on the output - it is usually necessary to insert
an additional format filter immediately following in the graph to get the output in a
supported format.
avgblur_vulkan
Apply an average blur filter, implemented on the GPU using Vulkan.
The filter accepts the following options:
sizeX
Set horizontal radius size. Range is "[1, 32]" and default value is 3.
sizeY
Set vertical radius size. Range is "[1, 32]" and default value is 3.
planes
Set which planes to filter. Default value is 0xf, by which all planes are processed.
blend_vulkan
Blend two Vulkan frames into each other.
The "blend" filter takes two input streams and outputs one stream, the first input is the
"top" layer and second input is "bottom" layer. By default, the output terminates when
the longest input terminates.
A description of the accepted options follows.
c0_mode
c1_mode
c2_mode
c3_mode
all_mode
Set blend mode for specific pixel component or all pixel components in case of
all_mode. Default value is "normal".
Available values for component modes are:
normal
multiply
bwdif_vulkan
Deinterlacer using bwdif, the "Bob Weaver Deinterlacing Filter" algorithm, implemented on
the GPU using Vulkan.
It accepts the following parameters:
mode
The interlacing mode to adopt. It accepts one of the following values:
0, send_frame
Output one frame for each frame.
1, send_field
Output one frame for each field.
The default value is "send_field".
parity
The picture field parity assumed for the input interlaced video. It accepts one of the
following values:
0, tff
Assume the top field is first.
1, bff
Assume the bottom field is first.
-1, auto
Enable automatic detection of field parity.
The default value is "auto". If the interlacing is unknown or the decoder does not
export this information, top field first will be assumed.
deint
Specify which frames to deinterlace. Accepts one of the following values:
0, all
Deinterlace all frames.
1, interlaced
Only deinterlace frames marked as interlaced.
The default value is "all".
chromaber_vulkan
Apply an effect that emulates chromatic aberration. Works best with RGB inputs, but
provides a similar effect with YCbCr inputs too.
dist_x
Horizontal displacement multiplier. Each chroma pixel's position will be multiplied by
this amount, starting from the center of the image. Default is 0.
dist_y
Similarly, this sets the vertical displacement multiplier. Default is 0.
color_vulkan
Video source that creates a Vulkan frame of a solid color. Useful for benchmarking, or
overlaying.
It accepts the following parameters:
color
The color to use. Either a name, or a hexadecimal value. The default value is
"black".
size
The size of the output frame. Default value is "1920x1080".
rate
The framerate to output at. Default value is 60 frames per second.
duration
The video duration. Default value is -0.000001.
sar The video signal aspect ratio. Default value is "1/1".
format
The pixel format of the output Vulkan frames. Default value is "yuv444p".
out_range
Set the output YCbCr sample range.
This allows the autodetected value to be overridden as well as allows forcing a
specific value used for the output and encoder. If not specified, the range depends on
the pixel format. Possible values:
auto/unknown
Choose automatically.
jpeg/full/pc
Set full range (0-255 in case of 8-bit luma).
mpeg/limited/tv
Set "MPEG" range (16-235 in case of 8-bit luma).
vflip_vulkan
Flips an image vertically.
hflip_vulkan
Flips an image horizontally.
flip_vulkan
Flips an image along both the vertical and horizontal axis.
gblur_vulkan
Apply Gaussian blur filter on Vulkan frames.
The filter accepts the following options:
sigma
Set horizontal sigma, standard deviation of Gaussian blur. Default is 0.5.
sigmaV
Set vertical sigma, if negative it will be same as "sigma". Default is -1.
planes
Set which planes to filter. By default all planes are filtered.
size
Set the kernel size along the horizontal axis. Default is 19.
sizeV
Set the kernel size along the vertical axis. Default is 0, which sets to use the same
value as size.
nlmeans_vulkan
Denoise frames using Non-Local Means algorithm, implemented on the GPU using Vulkan.
Supports more pixel formats than nlmeans or nlmeans_opencl, including alpha channel
support.
The filter accepts the following options.
s Set denoising strength for all components. Default is 1.0. Must be in range [1.0,
100.0].
p Set patch size for all planes. Default is 7. Must be odd number in range [0, 99].
r Set research size. Default is 15. Must be odd number in range [0, 99].
t Set parallelism. Default is 36. Must be a number in the range [1, 168]. Larger values
may speed up processing, at the cost of more VRAM. Lower values will slow it down,
reducing VRAM usage. Only supported on GPUs with atomic float operations (RDNA3+,
Ampere+).
s0
s1
s2
s3 Set denoising strength for a specific component. Default is 1, equal to s. Must be
odd number in range [1, 100].
p0
p1
p2
p3 Set patch size for a specific component. Default is 7, equal to p. Must be odd number
in range [0, 99].
overlay_vulkan
Overlay one video on top of another.
It takes two inputs and has one output. The first input is the "main" video on which the
second input is overlaid. This filter requires all inputs to use the same pixel format.
So, format conversion may be needed.
The filter accepts the following options:
x Set the x coordinate of the overlaid video on the main video. Default value is 0.
y Set the y coordinate of the overlaid video on the main video. Default value is 0.
transpose_vt
Transpose rows with columns in the input video and optionally flip it. For more in depth
examples see the transpose video filter, which shares mostly the same options.
It accepts the following parameters:
dir Specify the transposition direction.
Can assume the following values:
cclock_flip
Rotate by 90 degrees counterclockwise and vertically flip. (default)
clock
Rotate by 90 degrees clockwise.
cclock
Rotate by 90 degrees counterclockwise.
clock_flip
Rotate by 90 degrees clockwise and vertically flip.
hflip
Flip the input video horizontally.
vflip
Flip the input video vertically.
passthrough
Do not apply the transposition if the input geometry matches the one specified by the
specified value. It accepts the following values:
none
Always apply transposition. (default)
portrait
Preserve portrait geometry (when height >= width).
landscape
Preserve landscape geometry (when width >= height).
transpose_vulkan
Transpose rows with columns in the input video and optionally flip it. For more in depth
examples see the transpose video filter, which shares mostly the same options.
It accepts the following parameters:
dir Specify the transposition direction.
Can assume the following values:
cclock_flip
Rotate by 90 degrees counterclockwise and vertically flip. (default)
clock
Rotate by 90 degrees clockwise.
cclock
Rotate by 90 degrees counterclockwise.
clock_flip
Rotate by 90 degrees clockwise and vertically flip.
passthrough
Do not apply the transposition if the input geometry matches the one specified by the
specified value. It accepts the following values:
none
Always apply transposition. (default)
portrait
Preserve portrait geometry (when height >= width).
landscape
Preserve landscape geometry (when width >= height).
QSV VIDEO FILTERS
Below is a description of the currently available QSV video filters.
To enable compilation of these filters you need to configure FFmpeg with "--enable-libmfx"
or "--enable-libvpl".
To use QSV filters, you need to setup the QSV device correctly. For more information,
please read <https://trac.ffmpeg.org/wiki/Hardware/QuickSync>
hstack_qsv
Stack input videos horizontally.
This is the QSV variant of the hstack filter, each input stream may have different height,
this filter will scale down/up each input stream while keeping the original aspect.
It accepts the following options:
inputs
See hstack.
shortest
See hstack.
height
Set height of output. If set to 0, this filter will set height of output to height of
the first input stream. Default value is 0.
vstack_qsv
Stack input videos vertically.
This is the QSV variant of the vstack filter, each input stream may have different width,
this filter will scale down/up each input stream while keeping the original aspect.
It accepts the following options:
inputs
See vstack.
shortest
See vstack.
width
Set width of output. If set to 0, this filter will set width of output to width of the
first input stream. Default value is 0.
xstack_qsv
Stack video inputs into custom layout.
This is the QSV variant of the xstack filter.
It accepts the following options:
inputs
See xstack.
shortest
See xstack.
layout
See xstack. Moreover, this permits the user to supply output size for each input
stream.
xstack_qsv=inputs=4:layout=0_0_1920x1080|0_h0_1920x1080|w0_0_1920x1080|w0_h0_1920x1080
grid
See xstack.
grid_tile_size
Set output size for each input stream when grid is set. If this option is not set,
this filter will set output size by default to the size of the first input stream. For
the syntax of this option, check the "Video size" section in the ffmpeg-utils manual.
fill
See xstack.
VIDEO SOURCES
Below is a description of the currently available video sources.
buffer
Buffer video frames, and make them available to the filter chain.
This source is mainly intended for a programmatic use, in particular through the interface
defined in libavfilter/buffersrc.h.
It accepts the following parameters:
video_size
Specify the size (width and height) of the buffered video frames. For the syntax of
this option, check the "Video size" section in the ffmpeg-utils manual.
width
The input video width.
height
The input video height.
pix_fmt
A string representing the pixel format of the buffered video frames. It may be a
number corresponding to a pixel format, or a pixel format name.
time_base
Specify the timebase assumed by the timestamps of the buffered frames.
frame_rate
Specify the frame rate expected for the video stream.
colorspace
A string representing the color space of the buffered video frames. It may be a
number corresponding to a color space, or a color space name.
range
A string representing the color range of the buffered video frames. It may be a
number corresponding to a color range, or a color range name.
pixel_aspect, sar
The sample (pixel) aspect ratio of the input video.
hw_frames_ctx
When using a hardware pixel format, this should be a reference to an AVHWFramesContext
describing input frames.
For example:
buffer=width=320:height=240:pix_fmt=yuv410p:time_base=1/24:sar=1
will instruct the source to accept video frames with size 320x240 and with format
"yuv410p", assuming 1/24 as the timestamps timebase and square pixels (1:1 sample aspect
ratio). Since the pixel format with name "yuv410p" corresponds to the number 6 (check the
enum AVPixelFormat definition in libavutil/pixfmt.h), this example corresponds to:
buffer=size=320x240:pixfmt=6:time_base=1/24:pixel_aspect=1/1
Alternatively, the options can be specified as a flat string, but this syntax is
deprecated:
width:height:pix_fmt:time_base.num:time_base.den:pixel_aspect.num:pixel_aspect.den
cellauto
Create a pattern generated by an elementary cellular automaton.
The initial state of the cellular automaton can be defined through the filename and
pattern options. If such options are not specified an initial state is created randomly.
At each new frame a new row in the video is filled with the result of the cellular
automaton next generation. The behavior when the whole frame is filled is defined by the
scroll option.
This source accepts the following options:
filename, f
Read the initial cellular automaton state, i.e. the starting row, from the specified
file. In the file, each non-whitespace character is considered an alive cell, a
newline will terminate the row, and further characters in the file will be ignored.
pattern, p
Read the initial cellular automaton state, i.e. the starting row, from the specified
string.
Each non-whitespace character in the string is considered an alive cell, a newline
will terminate the row, and further characters in the string will be ignored.
rate, r
Set the video rate, that is the number of frames generated per second. Default is 25.
random_fill_ratio, ratio
Set the random fill ratio for the initial cellular automaton row. It is a floating
point number value ranging from 0 to 1, defaults to 1/PHI.
This option is ignored when a file or a pattern is specified.
random_seed, seed
Set the seed for filling randomly the initial row, must be an integer included between
0 and UINT32_MAX. If not specified, or if explicitly set to -1, the filter will try to
use a good random seed on a best effort basis.
rule
Set the cellular automaton rule, it is a number ranging from 0 to 255. Default value
is 110.
size, s
Set the size of the output video. For the syntax of this option, check the "Video
size" section in the ffmpeg-utils manual.
If filename or pattern is specified, the size is set by default to the width of the
specified initial state row, and the height is set to width * PHI.
If size is set, it must contain the width of the specified pattern string, and the
specified pattern will be centered in the larger row.
If a filename or a pattern string is not specified, the size value defaults to
"320x518" (used for a randomly generated initial state).
scroll
If set to 1, scroll the output upward when all the rows in the output have been
already filled. If set to 0, the new generated row will be written over the top row
just after the bottom row is filled. Defaults to 1.
start_full, full
If set to 1, completely fill the output with generated rows before outputting the
first frame. This is the default behavior, for disabling set the value to 0.
stitch
If set to 1, stitch the left and right row edges together. This is the default
behavior, for disabling set the value to 0.
Examples
• Read the initial state from pattern, and specify an output of size 200x400.
cellauto=f=pattern:s=200x400
• Generate a random initial row with a width of 200 cells, with a fill ratio of 2/3:
cellauto=ratio=2/3:s=200x200
• Create a pattern generated by rule 18 starting by a single alive cell centered on an
initial row with width 100:
cellauto=p=@s=100x400:full=0:rule=18
• Specify a more elaborated initial pattern:
cellauto=p='@@ @ @@':s=100x400:full=0:rule=18
coreimagesrc
Video source generated on GPU using Apple's CoreImage API on OSX.
This video source is a specialized version of the coreimage video filter. Use a core
image generator at the beginning of the applied filterchain to generate the content.
The coreimagesrc video source accepts the following options:
list_generators
List all available generators along with all their respective options as well as
possible minimum and maximum values along with the default values.
list_generators=true
size, s
Specify the size of the sourced video. For the syntax of this option, check the "Video
size" section in the ffmpeg-utils manual. The default value is "320x240".
rate, r
Specify the frame rate of the sourced video, as the number of frames generated per
second. It has to be a string in the format frame_rate_num/frame_rate_den, an integer
number, a floating point number or a valid video frame rate abbreviation. The default
value is "25".
sar Set the sample aspect ratio of the sourced video.
duration, d
Set the duration of the sourced video. See the Time duration section in the
ffmpeg-utils(1) manual for the accepted syntax.
If not specified, or the expressed duration is negative, the video is supposed to be
generated forever.
Additionally, all options of the coreimage video filter are accepted. A complete
filterchain can be used for further processing of the generated input without CPU-HOST
transfer. See coreimage documentation and examples for details.
Examples
• Use CIQRCodeGenerator to create a QR code for the FFmpeg homepage, given as complete
and escaped command-line for Apple's standard bash shell:
ffmpeg -f lavfi -i coreimagesrc=s=100x100:filter=CIQRCodeGenerator@inputMessage=https\\\\\://FFmpeg.org/@inputCorrectionLevel=H -frames:v 1 QRCode.png
This example is equivalent to the QRCode example of coreimage without the need for a
nullsrc video source.
ddagrab
Captures the Windows Desktop via Desktop Duplication API.
The filter exclusively returns D3D11 Hardware Frames, for on-gpu encoding or processing.
So an explicit hwdownload is needed for any kind of software processing.
It accepts the following options:
output_idx
DXGI Output Index to capture.
Usually corresponds to the index Windows has given the screen minus one, so it's
starting at 0.
Defaults to output 0.
draw_mouse
Whether to draw the mouse cursor.
Defaults to true.
Only affects hardware cursors. If a game or application renders its own cursor, it'll
always be captured.
framerate
Maximum framerate at which the desktop will be captured - the interval between
successive frames will not be smaller than the inverse of the framerate. When
dup_frames is true (the default) and the desktop is not being updated often enough,
the filter will duplicate a previous frame. Note that there is no background buffering
going on, so when the filter is not polled often enough then the actual inter-frame
interval may be significantly larger.
Defaults to 30 FPS.
video_size
Specify the size of the captured video.
Defaults to the full size of the screen.
Cropped from the bottom/right if smaller than screen size.
offset_x
Horizontal offset of the captured video.
offset_y
Vertical offset of the captured video.
output_fmt
Desired filter output format. Defaults to 8 Bit BGRA.
It accepts the following values:
auto
Passes all supported output formats to DDA and returns what DDA decides to use.
8bit
bgra
8 Bit formats always work, and DDA will convert to them if necessary.
10bit
x2bgr10
Filter initialization will fail if 10 bit format is requested but unavailable.
dup_frames
When this option is set to true (the default), the filter will duplicate frames when
the desktop has not been updated in order to maintain approximately constant target
framerate. When this option is set to false, the filter will wait for the desktop to
be updated (inter-frame intervals may vary significantly in this case).
Examples
Capture primary screen and encode using nvenc:
ffmpeg -f lavfi -i ddagrab -c:v h264_nvenc -cq 18 output.mp4
You can also skip the lavfi device and directly use the filter. Also demonstrates
downloading the frame and encoding with libx264. Explicit output format specification is
required in this case:
ffmpeg -filter_complex ddagrab=output_idx=1:framerate=60,hwdownload,format=bgra -c:v libx264 -crf 18 output.mp4
If you want to capture only a subsection of the desktop, this can be achieved by
specifying a smaller size and its offsets into the screen:
ddagrab=video_size=800x600:offset_x=100:offset_y=100
gradients
Generate several gradients.
size, s
Set frame size. For the syntax of this option, check the "Video size" section in the
ffmpeg-utils manual. Default value is "640x480".
rate, r
Set frame rate, expressed as number of frames per second. Default value is "25".
c0, c1, c2, c3, c4, c5, c6, c7
Set 8 colors. Default values for colors is to pick random one.
x0, y0, y0, y1
Set gradient line source and destination points. If negative or out of range, random
ones are picked.
nb_colors, n
Set number of colors to use at once. Allowed range is from 2 to 8. Default value is 2.
seed
Set seed for picking gradient line points.
duration, d
Set the duration of the sourced video. See the Time duration section in the
ffmpeg-utils(1) manual for the accepted syntax.
If not specified, or the expressed duration is negative, the video is supposed to be
generated forever.
speed
Set speed of gradients rotation.
type, t
Set type of gradients. Available values are:
linear
radial
circular
spiral
square
Default type is linear.
Commands
This source supports the some above options as commands.
mandelbrot
Generate a Mandelbrot set fractal, and progressively zoom towards the point specified with
start_x and start_y.
This source accepts the following options:
end_pts
Set the terminal pts value. Default value is 400.
end_scale
Set the terminal scale value. Must be a floating point value. Default value is 0.3.
inner
Set the inner coloring mode, that is the algorithm used to draw the Mandelbrot fractal
internal region.
It shall assume one of the following values:
black
Set black mode.
convergence
Show time until convergence.
mincol
Set color based on point closest to the origin of the iterations.
period
Set period mode.
Default value is mincol.
bailout
Set the bailout value. Default value is 10.0.
maxiter
Set the maximum of iterations performed by the rendering algorithm. Default value is
7189.
outer
Set outer coloring mode. It shall assume one of following values:
iteration_count
Set iteration count mode.
normalized_iteration_count
set normalized iteration count mode.
Default value is normalized_iteration_count.
rate, r
Set frame rate, expressed as number of frames per second. Default value is "25".
size, s
Set frame size. For the syntax of this option, check the "Video size" section in the
ffmpeg-utils manual. Default value is "640x480".
start_scale
Set the initial scale value. Default value is 3.0.
start_x
Set the initial x position. Must be a floating point value between -100 and 100.
Default value is -0.743643887037158704752191506114774.
start_y
Set the initial y position. Must be a floating point value between -100 and 100.
Default value is -0.131825904205311970493132056385139.
mptestsrc
Generate various test patterns, as generated by the MPlayer test filter.
The size of the generated video is fixed, and is 256x256. This source is useful in
particular for testing encoding features.
This source accepts the following options:
rate, r
Specify the frame rate of the sourced video, as the number of frames generated per
second. It has to be a string in the format frame_rate_num/frame_rate_den, an integer
number, a floating point number or a valid video frame rate abbreviation. The default
value is "25".
duration, d
Set the duration of the sourced video. See the Time duration section in the
ffmpeg-utils(1) manual for the accepted syntax.
If not specified, or the expressed duration is negative, the video is supposed to be
generated forever.
test, t
Set the number or the name of the test to perform. Supported tests are:
dc_luma
dc_chroma
freq_luma
freq_chroma
amp_luma
amp_chroma
cbp
mv
ring1
ring2
all
max_frames, m
Set the maximum number of frames generated for each test, default value is 30.
Default value is "all", which will cycle through the list of all tests.
Some examples:
mptestsrc=t=dc_luma
will generate a "dc_luma" test pattern.
frei0r_src
Provide a frei0r source.
To enable compilation of this filter you need to install the frei0r header and configure
FFmpeg with "--enable-frei0r".
This source accepts the following parameters:
size
The size of the video to generate. For the syntax of this option, check the "Video
size" section in the ffmpeg-utils manual.
framerate
The framerate of the generated video. It may be a string of the form num/den or a
frame rate abbreviation.
filter_name
The name to the frei0r source to load. For more information regarding frei0r and how
to set the parameters, read the frei0r section in the video filters documentation.
filter_params
A '|'-separated list of parameters to pass to the frei0r source.
For example, to generate a frei0r partik0l source with size 200x200 and frame rate 10
which is overlaid on the overlay filter main input:
frei0r_src=size=200x200:framerate=10:filter_name=partik0l:filter_params=1234 [overlay]; [in][overlay] overlay
life
Generate a life pattern.
This source is based on a generalization of John Conway's life game.
The sourced input represents a life grid, each pixel represents a cell which can be in one
of two possible states, alive or dead. Every cell interacts with its eight neighbours,
which are the cells that are horizontally, vertically, or diagonally adjacent.
At each interaction the grid evolves according to the adopted rule, which specifies the
number of neighbor alive cells which will make a cell stay alive or born. The rule option
allows one to specify the rule to adopt.
This source accepts the following options:
filename, f
Set the file from which to read the initial grid state. In the file, each non-
whitespace character is considered an alive cell, and newline is used to delimit the
end of each row.
If this option is not specified, the initial grid is generated randomly.
rate, r
Set the video rate, that is the number of frames generated per second. Default is 25.
random_fill_ratio, ratio
Set the random fill ratio for the initial random grid. It is a floating point number
value ranging from 0 to 1, defaults to 1/PHI. It is ignored when a file is specified.
random_seed, seed
Set the seed for filling the initial random grid, must be an integer included between
0 and UINT32_MAX. If not specified, or if explicitly set to -1, the filter will try to
use a good random seed on a best effort basis.
rule
Set the life rule.
A rule can be specified with a code of the kind "SNS/BNB", where NS and NB are
sequences of numbers in the range 0-8, NS specifies the number of alive neighbor cells
which make a live cell stay alive, and NB the number of alive neighbor cells which
make a dead cell to become alive (i.e. to "born"). "s" and "b" can be used in place
of "S" and "B", respectively.
Alternatively a rule can be specified by an 18-bits integer. The 9 high order bits are
used to encode the next cell state if it is alive for each number of neighbor alive
cells, the low order bits specify the rule for "borning" new cells. Higher order bits
encode for an higher number of neighbor cells. For example the number 6153 =
"(12<<9)+9" specifies a stay alive rule of 12 and a born rule of 9, which corresponds
to "S23/B03".
Default value is "S23/B3", which is the original Conway's game of life rule, and will
keep a cell alive if it has 2 or 3 neighbor alive cells, and will born a new cell if
there are three alive cells around a dead cell.
size, s
Set the size of the output video. For the syntax of this option, check the "Video
size" section in the ffmpeg-utils manual.
If filename is specified, the size is set by default to the same size of the input
file. If size is set, it must contain the size specified in the input file, and the
initial grid defined in that file is centered in the larger resulting area.
If a filename is not specified, the size value defaults to "320x240" (used for a
randomly generated initial grid).
stitch
If set to 1, stitch the left and right grid edges together, and the top and bottom
edges also. Defaults to 1.
mold
Set cell mold speed. If set, a dead cell will go from death_color to mold_color with a
step of mold. mold can have a value from 0 to 255.
life_color
Set the color of living (or new born) cells.
death_color
Set the color of dead cells. If mold is set, this is the first color used to represent
a dead cell.
mold_color
Set mold color, for definitely dead and moldy cells.
For the syntax of these 3 color options, check the "Color" section in the ffmpeg-utils
manual.
Examples
• Read a grid from pattern, and center it on a grid of size 300x300 pixels:
life=f=pattern:s=300x300
• Generate a random grid of size 200x200, with a fill ratio of 2/3:
life=ratio=2/3:s=200x200
• Specify a custom rule for evolving a randomly generated grid:
life=rule=S14/B34
• Full example with slow death effect (mold) using ffplay:
ffplay -f lavfi life=s=300x200:mold=10:r=60:ratio=0.1:death_color=#C83232:life_color=#00ff00,scale=1200:800:flags=16
perlin
Generate Perlin noise.
Perlin noise is a kind of noise with local continuity in space. This can be used to
generate patterns with continuity in space and time, e.g. to simulate smoke, fluids, or
terrain.
In case more than one octave is specified through the octaves option, Perlin noise is
generated as a sum of components, each one with doubled frequency. In this case the
persistence option specify the ratio of the amplitude with respect to the previous
component. More octave components enable to specify more high frequency details in the
generated noise (e.g. small size variations due to boulders in a generated terrain).
Options
size, s
Specify the size (width and height) of the buffered video frames. For the syntax of
this option, check the "Video size" section in the ffmpeg-utils manual. Default value
is "320x240".
rate, r
Specify the frame rate expected for the video stream, expressed as a number of frames
per second. Default value is 25.
octaves
Specify the total number of components making up the noise, each one with doubled
frequency. Default value is 1.
persistence
Set the ratio used to compute the amplitude of the next octave component with respect
to the previous component amplitude. Default value is 1.
xscale
yscale
Define a scale factor used to multiple the x, y coordinates. This can be useful to
define an effect with a pattern stretched along the x or y axis. Default value is 1.
tscale
Define a scale factor used to multiple the time coordinate. This can be useful to
change the time variation speed. Default value is 1.
random_mode
Set random mode used to compute initial pattern.
Supported values are:
random
Compute and use random seed.
ken Use the predefined initial pattern defined by Ken Perlin in the original article,
can be useful to compare the output with other sources.
seed
Use the value specified by random_seed option.
Default value is "random".
random_seed, seed
When random_mode is set to random_seed, use this value to compute the initial pattern.
Default value is 0.
Examples
• Generate single component:
perlin
• Use Perlin noise with 7 components, each one with a halved contribution to total
amplitude:
perlin=octaves=7:persistence=0.5
• Chain Perlin noise with the lutyuv to generate a black&white effect:
perlin=octaves=3:tscale=0.3,lutyuv=y='if(lt(val\,128)\,255\,0)'
• Stretch noise along the y axis, and convert gray level to red-only signal:
perlin=octaves=7:tscale=0.4:yscale=0.3,lutrgb=r=val:b=0:g=0
qrencodesrc
Generate a QR code using the libqrencode library (see
<https://fukuchi.org/works/qrencode/>).
To enable the compilation of this source, you need to configure FFmpeg with
"--enable-libqrencode".
The QR code is generated from the provided text or text pattern. The corresponding QR code
is scaled and put in the video output according to the specified output size options.
In case no text is specified, the QR code is not generated, but an empty colored output is
returned instead.
This source accepts the following options:
qrcode_width, q
padded_qrcode_width, Q
Specify an expression for the width of the rendered QR code, with and without padding.
The qrcode_width expression can reference the value set by the padded_qrcode_width
expression, and vice versa. By default padded_qrcode_width is set to qrcode_width,
meaning that there is no padding.
These expressions are evaluated only once, when initializing the source. See the
qrencode Expressions section for details.
Note that some of the constants are missing for the source (for example the x or t or
¸n), since they only makes sense when evaluating the expression for each frame rather
than at initialization time.
rate, r
Specify the frame rate of the sourced video, as the number of frames generated per
second. It has to be a string in the format frame_rate_num/frame_rate_den, an integer
number, a floating point number or a valid video frame rate abbreviation. The default
value is "25".
case_sensitive, cs
Instruct libqrencode to use case sensitive encoding. This is enabled by default. This
can be disabled to reduce the QR encoding size.
level, l
Specify the QR encoding error correction level. With an higher correction level, the
encoding size will increase but the code will be more robust to corruption. Lower
level is L.
It accepts the following values:
L
M
Q
H
expansion
Select how the input text is expanded. Can be either "none", or "normal" (default).
See the qrencode Text expansion section for details.
text
textfile
Define the text to be rendered. In case neither is specified, no QR is encoded (just
an empty colored frame).
In case expansion is enabled, the text is treated as a text template, using the
qrencode expansion mechanism. See the qrencode Text expansion section for details.
background_color, bc
foreground_color, fc
Set the QR code and background color. The default value of foreground_color is
"black", the default value of background_color is "white".
For the syntax of the color options, check the "Color" section in the ffmpeg-utils
manual.
Examples
• Generate a QR code encoding the specified text with the default size:
qrencodesrc=text=www.ffmpeg.org
• Same as below, but select blue on pink colors:
qrencodesrc=text=www.ffmpeg.org:bc=pink:fc=blue
• Generate a QR code with width of 200 pixels and padding, making the padded width 4/3
of the QR code width:
qrencodesrc=text=www.ffmpeg.org:q=200:Q=4/3*q
• Generate a QR code with padded width of 200 pixels and padding, making the QR code
width 3/4 of the padded width:
qrencodesrc=text=www.ffmpeg.org:Q=200:q=3/4*Q
• Generate a QR code encoding the frame number:
qrencodesrc=text=%{n}
• Generate a QR code encoding the GMT timestamp:
qrencodesrc=text=%{gmtime}
• Generate a QR code encoding the timestamp expressed as a float:
qrencodesrc=text=%{pts}
allrgb, allyuv, color, colorchart, colorspectrum, haldclutsrc, nullsrc, pal75bars, pal100bars,
rgbtestsrc, smptebars, smptehdbars, testsrc, testsrc2, yuvtestsrc
The "allrgb" source returns frames of size 4096x4096 of all rgb colors.
The "allyuv" source returns frames of size 4096x4096 of all yuv colors.
The "color" source provides an uniformly colored input.
The "colorchart" source provides a colors checker chart.
The "colorspectrum" source provides a color spectrum input.
The "haldclutsrc" source provides an identity Hald CLUT. See also haldclut filter.
The "nullsrc" source returns unprocessed video frames. It is mainly useful to be employed
in analysis / debugging tools, or as the source for filters which ignore the input data.
The "pal75bars" source generates a color bars pattern, based on EBU PAL recommendations
with 75% color levels.
The "pal100bars" source generates a color bars pattern, based on EBU PAL recommendations
with 100% color levels.
The "rgbtestsrc" source generates an RGB test pattern useful for detecting RGB vs BGR
issues. You should see a red, green and blue stripe from top to bottom.
The "smptebars" source generates a color bars pattern, based on the SMPTE Engineering
Guideline EG 1-1990.
The "smptehdbars" source generates a color bars pattern, based on the SMPTE RP 219-2002.
The "testsrc" source generates a test video pattern, showing a color pattern, a scrolling
gradient and a timestamp. This is mainly intended for testing purposes.
The "testsrc2" source is similar to testsrc, but supports more pixel formats instead of
just "rgb24". This allows using it as an input for other tests without requiring a format
conversion.
The "yuvtestsrc" source generates an YUV test pattern. You should see a y, cb and cr
stripe from top to bottom.
The sources accept the following parameters:
level
Specify the level of the Hald CLUT, only available in the "haldclutsrc" source. A
level of "N" generates a picture of "N*N*N" by "N*N*N" pixels to be used as identity
matrix for 3D lookup tables. Each component is coded on a "1/(N*N)" scale.
color, c
Specify the color of the source, only available in the "color" source. For the syntax
of this option, check the "Color" section in the ffmpeg-utils manual.
size, s
Specify the size of the sourced video. For the syntax of this option, check the "Video
size" section in the ffmpeg-utils manual. The default value is "320x240".
This option is not available with the "allrgb", "allyuv", and "haldclutsrc" filters.
rate, r
Specify the frame rate of the sourced video, as the number of frames generated per
second. It has to be a string in the format frame_rate_num/frame_rate_den, an integer
number, a floating point number or a valid video frame rate abbreviation. The default
value is "25".
duration, d
Set the duration of the sourced video. See the Time duration section in the
ffmpeg-utils(1) manual for the accepted syntax.
If not specified, or the expressed duration is negative, the video is supposed to be
generated forever.
Since the frame rate is used as time base, all frames including the last one will have
their full duration. If the specified duration is not a multiple of the frame
duration, it will be rounded up.
sar Set the sample aspect ratio of the sourced video.
alpha
Specify the alpha (opacity) of the background, only available in the "testsrc2"
source. The value must be between 0 (fully transparent) and 255 (fully opaque, the
default).
decimals, n
Set the number of decimals to show in the timestamp, only available in the "testsrc"
source.
The displayed timestamp value will correspond to the original timestamp value
multiplied by the power of 10 of the specified value. Default value is 0.
type
Set the type of the color spectrum, only available in the "colorspectrum" source. Can
be one of the following:
black
white
all
patch_size
Set patch size of single color patch, only available in the "colorchart" source.
Default is "64x64".
preset
Set colorchecker colors preset, only available in the "colorchart" source.
Available values are:
reference
skintones
Default value is "reference".
Examples
• Generate a video with a duration of 5.3 seconds, with size 176x144 and a frame rate of
10 frames per second:
testsrc=duration=5.3:size=qcif:rate=10
• The following graph description will generate a red source with an opacity of 0.2,
with size "qcif" and a frame rate of 10 frames per second:
color=c=red@0.2:s=qcif:r=10
• If the input content is to be ignored, "nullsrc" can be used. The following command
generates noise in the luma plane by employing the "geq" filter:
nullsrc=s=256x256, geq=random(1)*255:128:128
Commands
The "color" source supports the following commands:
c, color
Set the color of the created image. Accepts the same syntax of the corresponding color
option.
openclsrc
Generate video using an OpenCL program.
source
OpenCL program source file.
kernel
Kernel name in program.
size, s
Size of frames to generate. This must be set.
format
Pixel format to use for the generated frames. This must be set.
rate, r
Number of frames generated every second. Default value is '25'.
For details of how the program loading works, see the program_opencl filter.
Example programs:
• Generate a colour ramp by setting pixel values from the position of the pixel in the
output image. (Note that this will work with all pixel formats, but the generated
output will not be the same.)
__kernel void ramp(__write_only image2d_t dst,
unsigned int index)
{
int2 loc = (int2)(get_global_id(0), get_global_id(1));
float4 val;
val.xy = val.zw = convert_float2(loc) / convert_float2(get_image_dim(dst));
write_imagef(dst, loc, val);
}
• Generate a Sierpinski carpet pattern, panning by a single pixel each frame.
__kernel void sierpinski_carpet(__write_only image2d_t dst,
unsigned int index)
{
int2 loc = (int2)(get_global_id(0), get_global_id(1));
float4 value = 0.0f;
int x = loc.x + index;
int y = loc.y + index;
while (x > 0 || y > 0) {
if (x % 3 == 1 && y % 3 == 1) {
value = 1.0f;
break;
}
x /= 3;
y /= 3;
}
write_imagef(dst, loc, value);
}
sierpinski
Generate a Sierpinski carpet/triangle fractal, and randomly pan around.
This source accepts the following options:
size, s
Set frame size. For the syntax of this option, check the "Video size" section in the
ffmpeg-utils manual. Default value is "640x480".
rate, r
Set frame rate, expressed as number of frames per second. Default value is "25".
seed
Set seed which is used for random panning.
jump
Set max jump for single pan destination. Allowed range is from 1 to 10000.
type
Set fractal type, can be default "carpet" or "triangle".
zoneplate
Generate a zoneplate test video pattern.
This source accepts the following options:
size, s
Set frame size. For the syntax of this option, check the "Video size" section in the
ffmpeg-utils manual. Default value is "320x240".
rate, r
Set frame rate, expressed as number of frames per second. Default value is "25".
duration, d
Set the duration of the sourced video. See the Time duration section in the
ffmpeg-utils(1) manual for the accepted syntax.
If not specified, or the expressed duration is negative, the video is supposed to be
generated forever.
sar Set the sample aspect ratio of the sourced video.
precision
Set precision in bits for look-up table for sine calculations. Default value is 10.
Allowed range is from 4 to 16.
xo Set horizontal axis offset for output signal. Default value is 0.
yo Set vertical axis offset for output signal. Default value is 0.
to Set time axis offset for output signal. Default value is 0.
k0 Set 0-order, constant added to signal phase. Default value is 0.
kx Set 1-order, phase factor multiplier for horizontal axis. Default value is 0.
ky Set 1-order, phase factor multiplier for vertical axis. Default value is 0.
kt Set 1-order, phase factor multiplier for time axis. Default value is 0.
kxt, kyt, kxy
Set phase factor multipliers for combination of spatial and temporal axis. Default
value is 0.
kx2 Set 2-order, phase factor multiplier for horizontal axis. Default value is 0.
ky2 Set 2-order, phase factor multiplier for vertical axis. Default value is 0.
kt2 Set 2-order, phase factor multiplier for time axis. Default value is 0.
ku Set the constant added to final phase to produce chroma-blue component of signal.
Default value is 0.
kv Set the constant added to final phase to produce chroma-red component of signal.
Default value is 0.
Commands
This source supports the some above options as commands.
Examples
• Generate horizontal color sine sweep:
zoneplate=ku=512:kv=0:kt2=0:kx2=256:s=wvga:xo=-426:kt=11
• Generate vertical color sine sweep:
zoneplate=ku=512:kv=0:kt2=0:ky2=156:s=wvga:yo=-240:kt=11
• Generate circular zone-plate:
zoneplate=ku=512:kv=100:kt2=0:ky2=256:kx2=556:s=wvga:yo=0:kt=11
VIDEO SINKS
Below is a description of the currently available video sinks.
buffersink
Buffer video frames, and make them available to the end of the filter graph.
This sink is mainly intended for programmatic use, in particular through the interface
defined in libavfilter/buffersink.h or the options system.
It accepts a pointer to an AVBufferSinkContext structure, which defines the incoming
buffers' formats, to be passed as the opaque parameter to "avfilter_init_filter" for
initialization.
nullsink
Null video sink: do absolutely nothing with the input video. It is mainly useful as a
template and for use in analysis / debugging tools.
MULTIMEDIA FILTERS
Below is a description of the currently available multimedia filters.
a3dscope
Convert input audio to 3d scope video output.
The filter accepts the following options:
rate, r
Set frame rate, expressed as number of frames per second. Default value is "25".
size, s
Specify the video size for the output. For the syntax of this option, check the "Video
size" section in the ffmpeg-utils manual. Default value is "hd720".
fov Set the camera field of view. Default is 90 degrees. Allowed range is from 40 to 150.
roll
Set the camera roll.
pitch
Set the camera pitch.
yaw Set the camera yaw.
xzoom
Set the camera zoom on X-axis.
yzoom
Set the camera zoom on Y-axis.
zzoom
Set the camera zoom on Z-axis.
xpos
Set the camera position on X-axis.
ypos
Set the camera position on Y-axis.
zpos
Set the camera position on Z-axis.
length
Set the length of displayed audio waves in number of frames.
Commands
Filter supports the some above options as commands.
abitscope
Convert input audio to a video output, displaying the audio bit scope.
The filter accepts the following options:
rate, r
Set frame rate, expressed as number of frames per second. Default value is "25".
size, s
Specify the video size for the output. For the syntax of this option, check the "Video
size" section in the ffmpeg-utils manual. Default value is "1024x256".
colors
Specify list of colors separated by space or by '|' which will be used to draw
channels. Unrecognized or missing colors will be replaced by white color.
mode, m
Set output mode. Can be "bars" or "trace". Default is "bars".
adrawgraph
Draw a graph using input audio metadata.
See drawgraph
agraphmonitor
See graphmonitor.
ahistogram
Convert input audio to a video output, displaying the volume histogram.
The filter accepts the following options:
dmode
Specify how histogram is calculated.
It accepts the following values:
single
Use single histogram for all channels.
separate
Use separate histogram for each channel.
Default is "single".
rate, r
Set frame rate, expressed as number of frames per second. Default value is "25".
size, s
Specify the video size for the output. For the syntax of this option, check the "Video
size" section in the ffmpeg-utils manual. Default value is "hd720".
scale
Set display scale.
It accepts the following values:
log logarithmic
sqrt
square root
cbrt
cubic root
lin linear
rlog
reverse logarithmic
Default is "log".
ascale
Set amplitude scale.
It accepts the following values:
log logarithmic
lin linear
Default is "log".
acount
Set how much frames to accumulate in histogram. Default is 1. Setting this to -1
accumulates all frames.
rheight
Set histogram ratio of window height.
slide
Set sonogram sliding.
It accepts the following values:
replace
replace old rows with new ones.
scroll
scroll from top to bottom.
Default is "replace".
hmode
Set histogram mode.
It accepts the following values:
abs Use absolute values of samples.
sign
Use untouched values of samples.
Default is "abs".
aphasemeter
Measures phase of input audio, which is exported as metadata "lavfi.aphasemeter.phase",
representing mean phase of current audio frame. A video output can also be produced and is
enabled by default. The audio is passed through as first output.
Audio will be rematrixed to stereo if it has a different channel layout. Phase value is in
range "[-1, 1]" where -1 means left and right channels are completely out of phase and 1
means channels are in phase.
The filter accepts the following options, all related to its video output:
rate, r
Set the output frame rate. Default value is 25.
size, s
Set the video size for the output. For the syntax of this option, check the "Video
size" section in the ffmpeg-utils manual. Default value is "800x400".
rc
gc
bc Specify the red, green, blue contrast. Default values are 2, 7 and 1. Allowed range
is "[0, 255]".
mpc Set color which will be used for drawing median phase. If color is "none" which is
default, no median phase value will be drawn.
video
Enable video output. Default is enabled.
phasing detection
The filter also detects out of phase and mono sequences in stereo streams. It logs the
sequence start, end and duration when it lasts longer or as long as the minimum set.
The filter accepts the following options for this detection:
phasing
Enable mono and out of phase detection. Default is disabled.
tolerance, t
Set phase tolerance for mono detection, in amplitude ratio. Default is 0. Allowed
range is "[0, 1]".
angle, a
Set angle threshold for out of phase detection, in degree. Default is 170. Allowed
range is "[90, 180]".
duration, d
Set mono or out of phase duration until notification, expressed in seconds. Default is
2.
Examples
• Complete example with ffmpeg to detect 1 second of mono with 0.001 phase tolerance:
ffmpeg -i stereo.wav -af aphasemeter=video=0:phasing=1:duration=1:tolerance=0.001 -f null -
avectorscope
Convert input audio to a video output, representing the audio vector scope.
The filter is used to measure the difference between channels of stereo audio stream. A
monaural signal, consisting of identical left and right signal, results in straight
vertical line. Any stereo separation is visible as a deviation from this line, creating a
Lissajous figure. If the straight (or deviation from it) but horizontal line appears this
indicates that the left and right channels are out of phase.
The filter accepts the following options:
mode, m
Set the vectorscope mode.
Available values are:
lissajous
Lissajous rotated by 45 degrees.
lissajous_xy
Same as above but not rotated.
polar
Shape resembling half of circle.
Default value is lissajous.
size, s
Set the video size for the output. For the syntax of this option, check the "Video
size" section in the ffmpeg-utils manual. Default value is "400x400".
rate, r
Set the output frame rate. Default value is 25.
rc
gc
bc
ac Specify the red, green, blue and alpha contrast. Default values are 40, 160, 80 and
255. Allowed range is "[0, 255]".
rf
gf
bf
af Specify the red, green, blue and alpha fade. Default values are 15, 10, 5 and 5.
Allowed range is "[0, 255]".
zoom
Set the zoom factor. Default value is 1. Allowed range is "[0, 10]". Values lower
than 1 will auto adjust zoom factor to maximal possible value.
draw
Set the vectorscope drawing mode.
Available values are:
dot Draw dot for each sample.
line
Draw line between previous and current sample.
aaline
Draw anti-aliased line between previous and current sample.
Default value is dot.
scale
Specify amplitude scale of audio samples.
Available values are:
lin Linear.
sqrt
Square root.
cbrt
Cubic root.
log Logarithmic.
swap
Swap left channel axis with right channel axis.
mirror
Mirror axis.
none
No mirror.
x Mirror only x axis.
y Mirror only y axis.
xy Mirror both axis.
Examples
• Complete example using ffplay:
ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
[a] avectorscope=zoom=1.3:rc=2:gc=200:bc=10:rf=1:gf=8:bf=7 [out0]'
Commands
This filter supports the all above options as commands except options "size" and "rate".
bench, abench
Benchmark part of a filtergraph.
The filter accepts the following options:
action
Start or stop a timer.
Available values are:
start
Get the current time, set it as frame metadata (using the key
"lavfi.bench.start_time"), and forward the frame to the next filter.
stop
Get the current time and fetch the "lavfi.bench.start_time" metadata from the
input frame metadata to get the time difference. Time difference, average, maximum
and minimum time (respectively "t", "avg", "max" and "min") are then printed. The
timestamps are expressed in seconds.
Examples
• Benchmark selectivecolor filter:
bench=start,selectivecolor=reds=-.2 .12 -.49,bench=stop
concat
Concatenate audio and video streams, joining them together one after the other.
The filter works on segments of synchronized video and audio streams. All segments must
have the same number of streams of each type, and that will also be the number of streams
at output.
The filter accepts the following options:
n Set the number of segments. Default is 2.
v Set the number of output video streams, that is also the number of video streams in
each segment. Default is 1.
a Set the number of output audio streams, that is also the number of audio streams in
each segment. Default is 0.
unsafe
Activate unsafe mode: do not fail if segments have a different format.
The filter has v+a outputs: first v video outputs, then a audio outputs.
There are nx(v+a) inputs: first the inputs for the first segment, in the same order as the
outputs, then the inputs for the second segment, etc.
Related streams do not always have exactly the same duration, for various reasons
including codec frame size or sloppy authoring. For that reason, related synchronized
streams (e.g. a video and its audio track) should be concatenated at once. The concat
filter will use the duration of the longest stream in each segment (except the last one),
and if necessary pad shorter audio streams with silence.
For this filter to work correctly, all segments must start at timestamp 0.
All corresponding streams must have the same parameters in all segments; the filtering
system will automatically select a common pixel format for video streams, and a common
sample format, sample rate and channel layout for audio streams, but other settings, such
as resolution, must be converted explicitly by the user.
Different frame rates are acceptable but will result in variable frame rate at output; be
sure to configure the output file to handle it.
Examples
• Concatenate an opening, an episode and an ending, all in bilingual version (video in
stream 0, audio in streams 1 and 2):
ffmpeg -i opening.mkv -i episode.mkv -i ending.mkv -filter_complex \
'[0:0] [0:1] [0:2] [1:0] [1:1] [1:2] [2:0] [2:1] [2:2]
concat=n=3:v=1:a=2 [v] [a1] [a2]' \
-map '[v]' -map '[a1]' -map '[a2]' output.mkv
• Concatenate two parts, handling audio and video separately, using the (a)movie
sources, and adjusting the resolution:
movie=part1.mp4, scale=512:288 [v1] ; amovie=part1.mp4 [a1] ;
movie=part2.mp4, scale=512:288 [v2] ; amovie=part2.mp4 [a2] ;
[v1] [v2] concat [outv] ; [a1] [a2] concat=v=0:a=1 [outa]
Note that a desync will happen at the stitch if the audio and video streams do not
have exactly the same duration in the first file.
Commands
This filter supports the following commands:
next
Close the current segment and step to the next one
ebur128
EBU R128 scanner filter. This filter takes an audio stream and analyzes its loudness
level. By default, it logs a message at a frequency of 10Hz with the Momentary loudness
(identified by "M"), Short-term loudness ("S"), Integrated loudness ("I") and Loudness
Range ("LRA").
The filter can only analyze streams which have sample format is double-precision floating
point. The input stream will be converted to this specification, if needed. Users may need
to insert aformat and/or aresample filters after this filter to obtain the original
parameters.
The filter also has a video output (see the video option) with a real time graph to
observe the loudness evolution. The graphic contains the logged message mentioned above,
so it is not printed anymore when this option is set, unless the verbose logging is set.
The main graphing area contains the short-term loudness (3 seconds of analysis), and the
gauge on the right is for the momentary loudness (400 milliseconds), but can optionally be
configured to instead display short-term loudness (see gauge).
The green area marks a +/- 1LU target range around the target loudness (-23LUFS by
default, unless modified through target).
More information about the Loudness Recommendation EBU R128 on
<http://tech.ebu.ch/loudness>.
The filter accepts the following options:
video
Activate the video output. The audio stream is passed unchanged whether this option is
set or no. The video stream will be the first output stream if activated. Default is
0.
size
Set the video size. This option is for video only. For the syntax of this option,
check the "Video size" section in the ffmpeg-utils manual. Default and minimum
resolution is "640x480".
meter
Set the EBU scale meter. Default is 9. Common values are 9 and 18, respectively for
EBU scale meter +9 and EBU scale meter +18. Any other integer value between this range
is allowed.
metadata
Set metadata injection. If set to 1, the audio input will be segmented into 100ms
output frames, each of them containing various loudness information in metadata. All
the metadata keys are prefixed with "lavfi.r128.".
Default is 0.
framelog
Force the frame logging level.
Available values are:
quiet
logging disabled
info
information logging level
verbose
verbose logging level
By default, the logging level is set to info. If the video or the metadata options are
set, it switches to verbose.
peak
Set peak mode(s).
Available modes can be cumulated (the option is a "flag" type). Possible values are:
none
Disable any peak mode (default).
sample
Enable sample-peak mode.
Simple peak mode looking for the higher sample value. It logs a message for
sample-peak (identified by "SPK").
true
Enable true-peak mode.
If enabled, the peak lookup is done on an over-sampled version of the input stream
for better peak accuracy. It logs a message for true-peak. (identified by "TPK")
and true-peak per frame (identified by "FTPK"). This mode requires a build with
"libswresample".
dualmono
Treat mono input files as "dual mono". If a mono file is intended for playback on a
stereo system, its EBU R128 measurement will be perceptually incorrect. If set to
"true", this option will compensate for this effect. Multi-channel input files are
not affected by this option.
panlaw
Set a specific pan law to be used for the measurement of dual mono files. This
parameter is optional, and has a default value of -3.01dB.
target
Set a specific target level (in LUFS) used as relative zero in the visualization.
This parameter is optional and has a default value of -23LUFS as specified by EBU
R128. However, material published online may prefer a level of -16LUFS (e.g. for use
with podcasts or video platforms).
gauge
Set the value displayed by the gauge. Valid values are "momentary" and s "shortterm".
By default the momentary value will be used, but in certain scenarios it may be more
useful to observe the short term value instead (e.g. live mixing).
scale
Sets the display scale for the loudness. Valid parameters are "absolute" (in LUFS) or
"relative" (LU) relative to the target. This only affects the video output, not the
summary or continuous log output.
integrated
Read-only exported value for measured integrated loudness, in LUFS.
range
Read-only exported value for measured loudness range, in LU.
lra_low
Read-only exported value for measured LRA low, in LUFS.
lra_high
Read-only exported value for measured LRA high, in LUFS.
sample_peak
Read-only exported value for measured sample peak, in dBFS.
true_peak
Read-only exported value for measured true peak, in dBFS.
Examples
• Real-time graph using ffplay, with a EBU scale meter +18:
ffplay -f lavfi -i "amovie=input.mp3,ebur128=video=1:meter=18 [out0][out1]"
• Run an analysis with ffmpeg:
ffmpeg -nostats -i input.mp3 -filter_complex ebur128 -f null -
interleave, ainterleave
Temporally interleave frames from several inputs.
"interleave" works with video inputs, "ainterleave" with audio.
These filters read frames from several inputs and send the oldest queued frame to the
output.
Input streams must have well defined, monotonically increasing frame timestamp values.
In order to submit one frame to output, these filters need to enqueue at least one frame
for each input, so they cannot work in case one input is not yet terminated and will not
receive incoming frames.
For example consider the case when one input is a "select" filter which always drops input
frames. The "interleave" filter will keep reading from that input, but it will never be
able to send new frames to output until the input sends an end-of-stream signal.
Also, depending on inputs synchronization, the filters will drop frames in case one input
receives more frames than the other ones, and the queue is already filled.
These filters accept the following options:
nb_inputs, n
Set the number of different inputs, it is 2 by default.
duration
How to determine the end-of-stream.
longest
The duration of the longest input. (default)
shortest
The duration of the shortest input.
first
The duration of the first input.
Examples
• Interleave frames belonging to different streams using ffmpeg:
ffmpeg -i bambi.avi -i pr0n.mkv -filter_complex "[0:v][1:v] interleave" out.avi
• Add flickering blur effect:
select='if(gt(random(0), 0.2), 1, 2)':n=2 [tmp], boxblur=2:2, [tmp] interleave
latency, alatency
Measure filtering latency.
Report previous filter filtering latency, delay in number of audio samples for audio
filters or number of video frames for video filters.
On end of input stream, filter will report min and max measured latency for previous
running filter in filtergraph.
metadata, ametadata
Manipulate frame metadata.
This filter accepts the following options:
mode
Set mode of operation of the filter.
Can be one of the following:
select
If both "value" and "key" is set, select frames which have such metadata. If only
"key" is set, select every frame that has such key in metadata.
add Add new metadata "key" and "value". If key is already available do nothing.
modify
Modify value of already present key.
delete
If "value" is set, delete only keys that have such value. Otherwise, delete key.
If "key" is not set, delete all metadata values in the frame.
print
Print key and its value if metadata was found. If "key" is not set print all
metadata values available in frame.
key Set key used with all modes. Must be set for all modes except "print" and "delete".
value
Set metadata value which will be used. This option is mandatory for "modify" and "add"
mode.
function
Which function to use when comparing metadata value and "value".
Can be one of following:
same_str
Values are interpreted as strings, returns true if metadata value is same as
"value".
starts_with
Values are interpreted as strings, returns true if metadata value starts with the
"value" option string.
less
Values are interpreted as floats, returns true if metadata value is less than
"value".
equal
Values are interpreted as floats, returns true if "value" is equal with metadata
value.
greater
Values are interpreted as floats, returns true if metadata value is greater than
"value".
expr
Values are interpreted as floats, returns true if expression from option "expr"
evaluates to true.
ends_with
Values are interpreted as strings, returns true if metadata value ends with the
"value" option string.
expr
Set expression which is used when "function" is set to "expr". The expression is
evaluated through the eval API and can contain the following constants:
VALUE1, FRAMEVAL
Float representation of "value" from metadata key.
VALUE2, USERVAL
Float representation of "value" as supplied by user in "value" option.
file
If specified in "print" mode, output is written to the named file. Instead of plain
filename any writable url can be specified. Filename ``-'' is a shorthand for standard
output. If "file" option is not set, output is written to the log with AV_LOG_INFO
loglevel.
direct
Reduces buffering in print mode when output is written to a URL set using file.
Examples
• Print all metadata values for frames with key "lavfi.signalstats.YDIF" with values
between 0 and 1.
signalstats,metadata=print:key=lavfi.signalstats.YDIF:value=0:function=expr:expr='between(VALUE1,0,1)'
• Print silencedetect output to file metadata.txt.
silencedetect,ametadata=mode=print:file=metadata.txt
• Direct all metadata to a pipe with file descriptor 4.
metadata=mode=print:file='pipe\:4'
perms, aperms
Set read/write permissions for the output frames.
These filters are mainly aimed at developers to test direct path in the following filter
in the filtergraph.
The filters accept the following options:
mode
Select the permissions mode.
It accepts the following values:
none
Do nothing. This is the default.
ro Set all the output frames read-only.
rw Set all the output frames directly writable.
toggle
Make the frame read-only if writable, and writable if read-only.
random
Set each output frame read-only or writable randomly.
seed
Set the seed for the random mode, must be an integer included between 0 and
"UINT32_MAX". If not specified, or if explicitly set to -1, the filter will try to use
a good random seed on a best effort basis.
Note: in case of auto-inserted filter between the permission filter and the following one,
the permission might not be received as expected in that following filter. Inserting a
format or aformat filter before the perms/aperms filter can avoid this problem.
realtime, arealtime
Slow down filtering to match real time approximately.
These filters will pause the filtering for a variable amount of time to match the output
rate with the input timestamps. They are similar to the re option to "ffmpeg".
They accept the following options:
limit
Time limit for the pauses. Any pause longer than that will be considered a timestamp
discontinuity and reset the timer. Default is 2 seconds.
speed
Speed factor for processing. The value must be a float larger than zero. Values
larger than 1.0 will result in faster than realtime processing, smaller will slow
processing down. The limit is automatically adapted accordingly. Default is 1.0.
A processing speed faster than what is possible without these filters cannot be
achieved.
Commands
Both filters supports the all above options as commands.
segment, asegment
Split single input stream into multiple streams.
This filter does opposite of concat filters.
"segment" works on video frames, "asegment" on audio samples.
This filter accepts the following options:
timestamps
Timestamps of output segments separated by '|'. The first segment will run from the
beginning of the input stream. The last segment will run until the end of the input
stream
frames, samples
Exact frame/sample count to split the segments.
In all cases, prefixing an each segment with '+' will make it relative to the previous
segment.
Examples
• Split input audio stream into three output audio streams, starting at start of input
audio stream and storing that in 1st output audio stream, then following at 60th
second and storing than in 2nd output audio stream, and last after 150th second of
input audio stream store in 3rd output audio stream:
asegment=timestamps="60|150"
select, aselect
Select frames to pass in output.
This filter accepts the following options:
expr, e
Set expression, which is evaluated for each input frame.
If the expression is evaluated to zero, the frame is discarded.
If the evaluation result is negative or NaN, the frame is sent to the first output;
otherwise it is sent to the output with index "ceil(val)-1", assuming that the input
index starts from 0.
For example a value of 1.2 corresponds to the output with index "ceil(1.2)-1 = 2-1 =
1", that is the second output.
outputs, n
Set the number of outputs. The output to which to send the selected frame is based on
the result of the evaluation. Default value is 1.
The expression can contain the following constants:
n The (sequential) number of the filtered frame, starting from 0.
selected_n
The (sequential) number of the selected frame, starting from 0.
prev_selected_n
The sequential number of the last selected frame. It's NAN if undefined.
TB The timebase of the input timestamps.
pts The PTS (Presentation TimeStamp) of the filtered frame, expressed in TB units. It's
NAN if undefined.
t The PTS of the filtered frame, expressed in seconds. It's NAN if undefined.
prev_pts
The PTS of the previously filtered frame. It's NAN if undefined.
prev_selected_pts
The PTS of the last previously filtered frame. It's NAN if undefined.
prev_selected_t
The PTS of the last previously selected frame, expressed in seconds. It's NAN if
undefined.
start_pts
The first PTS in the stream which is not NAN. It remains NAN if not found.
start_t
The first PTS, in seconds, in the stream which is not NAN. It remains NAN if not
found.
pict_type (video only)
The type of the filtered frame. It can assume one of the following values:
I
P
B
S
SI
SP
BI
interlace_type (video only)
The frame interlace type. It can assume one of the following values:
PROGRESSIVE
The frame is progressive (not interlaced).
TOPFIRST
The frame is top-field-first.
BOTTOMFIRST
The frame is bottom-field-first.
consumed_sample_n (audio only)
the number of selected samples before the current frame
samples_n (audio only)
the number of samples in the current frame
sample_rate (audio only)
the input sample rate
key This is 1 if the filtered frame is a key-frame, 0 otherwise.
pos the position in the file of the filtered frame, -1 if the information is not available
(e.g. for synthetic video); deprecated, do not use
scene (video only)
value between 0 and 1 to indicate a new scene; a low value reflects a low probability
for the current frame to introduce a new scene, while a higher value means the current
frame is more likely to be one (see the example below)
concatdec_select
The concat demuxer can select only part of a concat input file by setting an inpoint
and an outpoint, but the output packets may not be entirely contained in the selected
interval. By using this variable, it is possible to skip frames generated by the
concat demuxer which are not exactly contained in the selected interval.
This works by comparing the frame pts against the lavf.concat.start_time and the
lavf.concat.duration packet metadata values which are also present in the decoded
frames.
The concatdec_select variable is -1 if the frame pts is at least start_time and either
the duration metadata is missing or the frame pts is less than start_time + duration,
0 otherwise, and NaN if the start_time metadata is missing.
That basically means that an input frame is selected if its pts is within the interval
set by the concat demuxer.
iw (video only)
Represents the width of the input video frame.
ih (video only)
Represents the height of the input video frame.
view (video only)
View ID for multi-view video.
The default value of the select expression is "1".
Examples
• Select all frames in input:
select
The example above is the same as:
select=1
• Skip all frames:
select=0
• Select only I-frames:
select='eq(pict_type\,I)'
• Select one frame every 100:
select='not(mod(n\,100))'
• Select only frames contained in the 10-20 time interval:
select=between(t\,10\,20)
• Select only I-frames contained in the 10-20 time interval:
select=between(t\,10\,20)*eq(pict_type\,I)
• Select frames with a minimum distance of 10 seconds:
select='isnan(prev_selected_t)+gte(t-prev_selected_t\,10)'
• Use aselect to select only audio frames with samples number > 100:
aselect='gt(samples_n\,100)'
• Create a mosaic of the first scenes:
ffmpeg -i video.avi -vf select='gt(scene\,0.4)',scale=160:120,tile -frames:v 1 preview.png
Comparing scene against a value between 0.3 and 0.5 is generally a sane choice.
• Send even and odd frames to separate outputs, and compose them:
select=n=2:e='mod(n, 2)+1' [odd][even]; [odd] pad=h=2*ih [tmp]; [tmp][even] overlay=y=h
• Select useful frames from an ffconcat file which is using inpoints and outpoints but
where the source files are not intra frame only.
ffmpeg -copyts -vsync 0 -segment_time_metadata 1 -i input.ffconcat -vf select=concatdec_select -af aselect=concatdec_select output.avi
sendcmd, asendcmd
Send commands to filters in the filtergraph.
These filters read commands to be sent to other filters in the filtergraph.
"sendcmd" must be inserted between two video filters, "asendcmd" must be inserted between
two audio filters, but apart from that they act the same way.
The specification of commands can be provided in the filter arguments with the commands
option, or in a file specified by the filename option.
These filters accept the following options:
commands, c
Set the commands to be read and sent to the other filters.
filename, f
Set the filename of the commands to be read and sent to the other filters.
Commands syntax
A commands description consists of a sequence of interval specifications, comprising a
list of commands to be executed when a particular event related to that interval occurs.
The occurring event is typically the current frame time entering or leaving a given time
interval.
An interval is specified by the following syntax:
<START>[-<END>] <COMMANDS>;
The time interval is specified by the START and END times. END is optional and defaults
to the maximum time.
The current frame time is considered within the specified interval if it is included in
the interval [START, END), that is when the time is greater or equal to START and is
lesser than END.
COMMANDS consists of a sequence of one or more command specifications, separated by ",",
relating to that interval. The syntax of a command specification is given by:
[<FLAGS>] <TARGET> <COMMAND> <ARG>
FLAGS is optional and specifies the type of events relating to the time interval which
enable sending the specified command, and must be a non-null sequence of identifier flags
separated by "+" or "|" and enclosed between "[" and "]".
The following flags are recognized:
enter
The command is sent when the current frame timestamp enters the specified interval. In
other words, the command is sent when the previous frame timestamp was not in the
given interval, and the current is.
leave
The command is sent when the current frame timestamp leaves the specified interval. In
other words, the command is sent when the previous frame timestamp was in the given
interval, and the current is not.
expr
The command ARG is interpreted as expression and result of expression is passed as
ARG.
The expression is evaluated through the eval API and can contain the following
constants:
POS Original position in the file of the frame, or undefined if undefined for the
current frame. Deprecated, do not use.
PTS The presentation timestamp in input.
N The count of the input frame for video or audio, starting from 0.
T The time in seconds of the current frame.
TS The start time in seconds of the current command interval.
TE The end time in seconds of the current command interval.
TI The interpolated time of the current command interval, TI = (T - TS) / (TE - TS).
W The video frame width.
H The video frame height.
If FLAGS is not specified, a default value of "[enter]" is assumed.
TARGET specifies the target of the command, usually the name of the filter class or a
specific filter instance name.
COMMAND specifies the name of the command for the target filter.
ARG is optional and specifies the optional list of argument for the given COMMAND.
Between one interval specification and another, whitespaces, or sequences of characters
starting with "#" until the end of line, are ignored and can be used to annotate comments.
A simplified BNF description of the commands specification syntax follows:
<COMMAND_FLAG> ::= "enter" | "leave"
<COMMAND_FLAGS> ::= <COMMAND_FLAG> [(+|"|")<COMMAND_FLAG>]
<COMMAND> ::= ["[" <COMMAND_FLAGS> "]"] <TARGET> <COMMAND> [<ARG>]
<COMMANDS> ::= <COMMAND> [,<COMMANDS>]
<INTERVAL> ::= <START>[-<END>] <COMMANDS>
<INTERVALS> ::= <INTERVAL>[;<INTERVALS>]
Examples
• Specify audio tempo change at second 4:
asendcmd=c='4.0 atempo tempo 1.5',atempo
• Target a specific filter instance:
asendcmd=c='4.0 atempo@my tempo 1.5',atempo@my
• Specify a list of drawtext and hue commands in a file.
# show text in the interval 5-10
5.0-10.0 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=hello world',
[leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=';
# desaturate the image in the interval 15-20
15.0-20.0 [enter] hue s 0,
[enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=nocolor',
[leave] hue s 1,
[leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=color';
# apply an exponential saturation fade-out effect, starting from time 25
25 [enter] hue s exp(25-t)
A filtergraph allowing to read and process the above command list stored in a file
test.cmd, can be specified with:
sendcmd=f=test.cmd,drawtext=fontfile=FreeSerif.ttf:text='',hue
setpts, asetpts
Change the PTS (presentation timestamp) of the input frames.
"setpts" works on video frames, "asetpts" on audio frames.
This filter accepts the following options:
expr
The expression which is evaluated for each frame to construct its timestamp.
The expression is evaluated through the eval API and can contain the following constants:
FRAME_RATE, FR
frame rate, only defined for constant frame-rate video
PTS The presentation timestamp in input
N The count of the input frame for video or the number of consumed samples, not
including the current frame for audio, starting from 0.
NB_CONSUMED_SAMPLES
The number of consumed samples, not including the current frame (only audio)
NB_SAMPLES, S
The number of samples in the current frame (only audio)
SAMPLE_RATE, SR
The audio sample rate.
STARTPTS
The PTS of the first frame.
STARTT
the time in seconds of the first frame
INTERLACED
State whether the current frame is interlaced.
T the time in seconds of the current frame
POS original position in the file of the frame, or undefined if undefined for the current
frame; deprecated, do not use
PREV_INPTS
The previous input PTS.
PREV_INT
previous input time in seconds
PREV_OUTPTS
The previous output PTS.
PREV_OUTT
previous output time in seconds
RTCTIME
The wallclock (RTC) time in microseconds. This is deprecated, use time(0) instead.
RTCSTART
The wallclock (RTC) time at the start of the movie in microseconds.
TB The timebase of the input timestamps.
T_CHANGE
Time of the first frame after command was applied or time of the first frame if no
commands.
Examples
• Start counting PTS from zero
setpts=PTS-STARTPTS
• Apply fast motion effect:
setpts=0.5*PTS
• Apply slow motion effect:
setpts=2.0*PTS
• Set fixed rate of 25 frames per second:
setpts=N/(25*TB)
• Apply a random jitter effect of +/-100 TB units:
setpts=PTS+randomi(0, -100\,100)
• Set fixed rate 25 fps with some jitter:
setpts='1/(25*TB) * (N + 0.05 * sin(N*2*PI/25))'
• Apply an offset of 10 seconds to the input PTS:
setpts=PTS+10/TB
• Generate timestamps from a "live source" and rebase onto the current timebase:
setpts='(RTCTIME - RTCSTART) / (TB * 1000000)'
• Generate timestamps by counting samples:
asetpts=N/SR/TB
Commands
Both filters support all above options as commands.
setrange
Force color range for the output video frame.
The "setrange" filter marks the color range property for the output frames. It does not
change the input frame, but only sets the corresponding property, which affects how the
frame is treated by following filters.
The filter accepts the following options:
range
Available values are:
auto
Keep the same color range property.
unspecified, unknown
Set the color range as unspecified.
limited, tv, mpeg
Set the color range as limited.
full, pc, jpeg
Set the color range as full.
settb, asettb
Set the timebase to use for the output frames timestamps. It is mainly useful for testing
timebase configuration.
It accepts the following parameters:
expr, tb
The expression which is evaluated into the output timebase.
The value for tb is an arithmetic expression representing a rational. The expression can
contain the constants "AVTB" (the default timebase), "intb" (the input timebase) and "sr"
(the sample rate, audio only). Default value is "intb".
Examples
• Set the timebase to 1/25:
settb=expr=1/25
• Set the timebase to 1/10:
settb=expr=0.1
• Set the timebase to 1001/1000:
settb=1+0.001
• Set the timebase to 2*intb:
settb=2*intb
• Set the default timebase value:
settb=AVTB
showcqt
Convert input audio to a video output representing frequency spectrum logarithmically
using Brown-Puckette constant Q transform algorithm with direct frequency domain
coefficient calculation (but the transform itself is not really constant Q, instead the Q
factor is actually variable/clamped), with musical tone scale, from E0 to D#10.
The filter accepts the following options:
size, s
Specify the video size for the output. It must be even. For the syntax of this option,
check the "Video size" section in the ffmpeg-utils manual. Default value is
"1920x1080".
fps, rate, r
Set the output frame rate. Default value is 25.
bar_h
Set the bargraph height. It must be even. Default value is -1 which computes the
bargraph height automatically.
axis_h
Set the axis height. It must be even. Default value is -1 which computes the axis
height automatically.
sono_h
Set the sonogram height. It must be even. Default value is -1 which computes the
sonogram height automatically.
fullhd
Set the fullhd resolution. This option is deprecated, use size, s instead. Default
value is 1.
sono_v, volume
Specify the sonogram volume expression. It can contain variables:
bar_v
the bar_v evaluated expression
frequency, freq, f
the frequency where it is evaluated
timeclamp, tc
the value of timeclamp option
and functions:
a_weighting(f)
A-weighting of equal loudness
b_weighting(f)
B-weighting of equal loudness
c_weighting(f)
C-weighting of equal loudness.
Default value is 16.
bar_v, volume2
Specify the bargraph volume expression. It can contain variables:
sono_v
the sono_v evaluated expression
frequency, freq, f
the frequency where it is evaluated
timeclamp, tc
the value of timeclamp option
and functions:
a_weighting(f)
A-weighting of equal loudness
b_weighting(f)
B-weighting of equal loudness
c_weighting(f)
C-weighting of equal loudness.
Default value is "sono_v".
sono_g, gamma
Specify the sonogram gamma. Lower gamma makes the spectrum more contrast, higher gamma
makes the spectrum having more range. Default value is 3. Acceptable range is "[1,
7]".
bar_g, gamma2
Specify the bargraph gamma. Default value is 1. Acceptable range is "[1, 7]".
bar_t
Specify the bargraph transparency level. Lower value makes the bargraph sharper.
Default value is 1. Acceptable range is "[0, 1]".
timeclamp, tc
Specify the transform timeclamp. At low frequency, there is trade-off between accuracy
in time domain and frequency domain. If timeclamp is lower, event in time domain is
represented more accurately (such as fast bass drum), otherwise event in frequency
domain is represented more accurately (such as bass guitar). Acceptable range is
"[0.002, 1]". Default value is 0.17.
attack
Set attack time in seconds. The default is 0 (disabled). Otherwise, it limits future
samples by applying asymmetric windowing in time domain, useful when low latency is
required. Accepted range is "[0, 1]".
basefreq
Specify the transform base frequency. Default value is 20.01523126408007475, which is
frequency 50 cents below E0. Acceptable range is "[10, 100000]".
endfreq
Specify the transform end frequency. Default value is 20495.59681441799654, which is
frequency 50 cents above D#10. Acceptable range is "[10, 100000]".
coeffclamp
This option is deprecated and ignored.
tlength
Specify the transform length in time domain. Use this option to control accuracy
trade-off between time domain and frequency domain at every frequency sample. It can
contain variables:
frequency, freq, f
the frequency where it is evaluated
timeclamp, tc
the value of timeclamp option.
Default value is "384*tc/(384+tc*f)".
count
Specify the transform count for every video frame. Default value is 6. Acceptable
range is "[1, 30]".
fcount
Specify the transform count for every single pixel. Default value is 0, which makes it
computed automatically. Acceptable range is "[0, 10]".
fontfile
Specify font file for use with freetype to draw the axis. If not specified, use
embedded font. Note that drawing with font file or embedded font is not implemented
with custom basefreq and endfreq, use axisfile option instead.
font
Specify fontconfig pattern. This has lower priority than fontfile. The ":" in the
pattern may be replaced by "|" to avoid unnecessary escaping.
fontcolor
Specify font color expression. This is arithmetic expression that should return
integer value 0xRRGGBB. It can contain variables:
frequency, freq, f
the frequency where it is evaluated
timeclamp, tc
the value of timeclamp option
and functions:
midi(f)
midi number of frequency f, some midi numbers: E0(16), C1(24), C2(36), A4(69)
r(x), g(x), b(x)
red, green, and blue value of intensity x.
Default value is "st(0, (midi(f)-59.5)/12); st(1, if(between(ld(0),0,1),
0.5-0.5*cos(2*PI*ld(0)), 0)); r(1-ld(1)) + b(ld(1))".
axisfile
Specify image file to draw the axis. This option override fontfile and fontcolor
option.
axis, text
Enable/disable drawing text to the axis. If it is set to 0, drawing to the axis is
disabled, ignoring fontfile and axisfile option. Default value is 1.
csp Set colorspace. The accepted values are:
unspecified
Unspecified (default)
bt709
BT.709
fcc FCC
bt470bg
BT.470BG or BT.601-6 625
smpte170m
SMPTE-170M or BT.601-6 525
smpte240m
SMPTE-240M
bt2020ncl
BT.2020 with non-constant luminance
cscheme
Set spectrogram color scheme. This is list of floating point values with format
"left_r|left_g|left_b|right_r|right_g|right_b". The default is "1|0.5|0|0|0.5|1".
Examples
• Playing audio while showing the spectrum:
ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt [out0]'
• Same as above, but with frame rate 30 fps:
ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt=fps=30:count=5 [out0]'
• Playing at 1280x720:
ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt=s=1280x720:count=4 [out0]'
• Disable sonogram display:
sono_h=0
• A1 and its harmonics: A1, A2, (near)E3, A3:
ffplay -f lavfi 'aevalsrc=0.1*sin(2*PI*55*t)+0.1*sin(4*PI*55*t)+0.1*sin(6*PI*55*t)+0.1*sin(8*PI*55*t),
asplit[a][out1]; [a] showcqt [out0]'
• Same as above, but with more accuracy in frequency domain:
ffplay -f lavfi 'aevalsrc=0.1*sin(2*PI*55*t)+0.1*sin(4*PI*55*t)+0.1*sin(6*PI*55*t)+0.1*sin(8*PI*55*t),
asplit[a][out1]; [a] showcqt=timeclamp=0.5 [out0]'
• Custom volume:
bar_v=10:sono_v=bar_v*a_weighting(f)
• Custom gamma, now spectrum is linear to the amplitude.
bar_g=2:sono_g=2
• Custom tlength equation:
tc=0.33:tlength='st(0,0.17); 384*tc / (384 / ld(0) + tc*f /(1-ld(0))) + 384*tc / (tc*f / ld(0) + 384 /(1-ld(0)))'
• Custom fontcolor and fontfile, C-note is colored green, others are colored blue:
fontcolor='if(mod(floor(midi(f)+0.5),12), 0x0000FF, g(1))':fontfile=myfont.ttf
• Custom font using fontconfig:
font='Courier New,Monospace,mono|bold'
• Custom frequency range with custom axis using image file:
axisfile=myaxis.png:basefreq=40:endfreq=10000
showcwt
Convert input audio to video output representing frequency spectrum using Continuous
Wavelet Transform and Morlet wavelet.
The filter accepts the following options:
size, s
Specify the video size for the output. For the syntax of this option, check the "Video
size" section in the ffmpeg-utils manual. Default value is "640x512".
rate, r
Set the output frame rate. Default value is 25.
scale
Set the frequency scale used. Allowed values are:
linear
log
bark
mel
erbs
sqrt
cbrt
qdrt
fm
Default value is "linear".
iscale
Set the intensity scale used. Allowed values are:
linear
log
sqrt
cbrt
qdrt
Default value is "log".
min Set the minimum frequency that will be used in output. Default is 20 Hz.
max Set the maximum frequency that will be used in output. Default is 20000 Hz. The real
frequency upper limit depends on input audio's sample rate and such will be enforced
on this value when it is set to value greater than Nyquist frequency.
imin
Set the minimum intensity that will be used in output.
imax
Set the maximum intensity that will be used in output.
logb
Set the logarithmic basis for brightness strength when mapping calculated magnitude
values to pixel values. Allowed range is from 0 to 1. Default value is 0.0001.
deviation
Set the frequency deviation. Lower values than 1 are more frequency oriented, while
higher values than 1 are more time oriented. Allowed range is from 0 to 10. Default
value is 1.
pps Set the number of pixel output per each second in one row. Allowed range is from 1 to
1024. Default value is 64.
mode
Set the output visual mode. Allowed values are:
magnitude
Show magnitude.
phase
Show only phase.
magphase
Show combination of magnitude and phase. Magnitude is mapped to brightness and
phase to color.
channel
Show unique color per channel magnitude.
stereo
Show unique color per stereo difference.
Default value is "magnitude".
slide
Set the output slide method. Allowed values are:
replace
scroll
frame
direction
Set the direction method for output slide method. Allowed values are:
lr Direction from left to right.
rl Direction from right to left.
ud Direction from up to down.
du Direction from down to up.
bar Set the ratio of bargraph display to display size. Default is 0.
rotation
Set color rotation, must be in [-1.0, 1.0] range. Default value is 0.
showfreqs
Convert input audio to video output representing the audio power spectrum. Audio
amplitude is on Y-axis while frequency is on X-axis.
The filter accepts the following options:
size, s
Specify size of video. For the syntax of this option, check the "Video size" section
in the ffmpeg-utils manual. Default is "1024x512".
rate, r
Set video rate. Default is 25.
mode
Set display mode. This set how each frequency bin will be represented.
It accepts the following values:
line
bar
dot
Default is "bar".
ascale
Set amplitude scale.
It accepts the following values:
lin Linear scale.
sqrt
Square root scale.
cbrt
Cubic root scale.
log Logarithmic scale.
Default is "log".
fscale
Set frequency scale.
It accepts the following values:
lin Linear scale.
log Logarithmic scale.
rlog
Reverse logarithmic scale.
Default is "lin".
win_size
Set window size. Allowed range is from 16 to 65536.
Default is 2048
win_func
Set windowing function.
It accepts the following values:
rect
bartlett
hanning
hamming
blackman
welch
flattop
bharris
bnuttall
bhann
sine
nuttall
lanczos
gauss
tukey
dolph
cauchy
parzen
poisson
bohman
kaiser
Default is "hanning".
overlap
Set window overlap. In range "[0, 1]". Default is 1, which means optimal overlap for
selected window function will be picked.
averaging
Set time averaging. Setting this to 0 will display current maximal peaks. Default is
1, which means time averaging is disabled.
colors
Specify list of colors separated by space or by '|' which will be used to draw channel
frequencies. Unrecognized or missing colors will be replaced by white color.
cmode
Set channel display mode.
It accepts the following values:
combined
separate
Default is "combined".
minamp
Set minimum amplitude used in "log" amplitude scaler.
data
Set data display mode.
It accepts the following values:
magnitude
phase
delay
Default is "magnitude".
channels
Set channels to use when processing audio. By default all are processed.
showspatial
Convert stereo input audio to a video output, representing the spatial relationship
between two channels.
The filter accepts the following options:
size, s
Specify the video size for the output. For the syntax of this option, check the "Video
size" section in the ffmpeg-utils manual. Default value is "512x512".
win_size
Set window size. Allowed range is from 1024 to 65536. Default size is 4096.
win_func
Set window function.
It accepts the following values:
rect
bartlett
hann
hanning
hamming
blackman
welch
flattop
bharris
bnuttall
bhann
sine
nuttall
lanczos
gauss
tukey
dolph
cauchy
parzen
poisson
bohman
kaiser
Default value is "hann".
rate, r
Set output framerate.
showspectrum
Convert input audio to a video output, representing the audio frequency spectrum.
The filter accepts the following options:
size, s
Specify the video size for the output. For the syntax of this option, check the "Video
size" section in the ffmpeg-utils manual. Default value is "640x512".
slide
Specify how the spectrum should slide along the window.
It accepts the following values:
replace
the samples start again on the left when they reach the right
scroll
the samples scroll from right to left
fullframe
frames are only produced when the samples reach the right
rscroll
the samples scroll from left to right
lreplace
the samples start again on the right when they reach the left
Default value is "replace".
mode
Specify display mode.
It accepts the following values:
combined
all channels are displayed in the same row
separate
all channels are displayed in separate rows
Default value is combined.
color
Specify display color mode.
It accepts the following values:
channel
each channel is displayed in a separate color
intensity
each channel is displayed using the same color scheme
rainbow
each channel is displayed using the rainbow color scheme
moreland
each channel is displayed using the moreland color scheme
nebulae
each channel is displayed using the nebulae color scheme
fire
each channel is displayed using the fire color scheme
fiery
each channel is displayed using the fiery color scheme
fruit
each channel is displayed using the fruit color scheme
cool
each channel is displayed using the cool color scheme
magma
each channel is displayed using the magma color scheme
green
each channel is displayed using the green color scheme
viridis
each channel is displayed using the viridis color scheme
plasma
each channel is displayed using the plasma color scheme
cividis
each channel is displayed using the cividis color scheme
terrain
each channel is displayed using the terrain color scheme
Default value is channel.
scale
Specify scale used for calculating intensity color values.
It accepts the following values:
lin linear
sqrt
square root, default
cbrt
cubic root
log logarithmic
4thrt
4th root
5thrt
5th root
Default value is sqrt.
fscale
Specify frequency scale.
It accepts the following values:
lin linear
log logarithmic
Default value is lin.
saturation
Set saturation modifier for displayed colors. Negative values provide alternative
color scheme. 0 is no saturation at all. Saturation must be in [-10.0, 10.0] range.
Default value is 1.
win_func
Set window function.
It accepts the following values:
rect
bartlett
hann
hanning
hamming
blackman
welch
flattop
bharris
bnuttall
bhann
sine
nuttall
lanczos
gauss
tukey
dolph
cauchy
parzen
poisson
bohman
kaiser
Default value is "hann".
orientation
Set orientation of time vs frequency axis. Can be "vertical" or "horizontal". Default
is "vertical".
overlap
Set ratio of overlap window. Default value is 0. When value is 1 overlap is set to
recommended size for specific window function currently used.
gain
Set scale gain for calculating intensity color values. Default value is 1.
data
Set which data to display. Can be "magnitude", default or "phase", or unwrapped phase:
"uphase".
rotation
Set color rotation, must be in [-1.0, 1.0] range. Default value is 0.
start
Set start frequency from which to display spectrogram. Default is 0.
stop
Set stop frequency to which to display spectrogram. Default is 0.
fps Set upper frame rate limit. Default is "auto", unlimited.
legend
Draw time and frequency axes and legends. Default is disabled.
drange
Set dynamic range used to calculate intensity color values. Default is 120 dBFS.
Allowed range is from 10 to 200.
limit
Set upper limit of input audio samples volume in dBFS. Default is 0 dBFS. Allowed
range is from -100 to 100.
opacity
Set opacity strength when using pixel format output with alpha component.
The usage is very similar to the showwaves filter; see the examples in that section.
Examples
• Large window with logarithmic color scaling:
showspectrum=s=1280x480:scale=log
• Complete example for a colored and sliding spectrum per channel using ffplay:
ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
[a] showspectrum=mode=separate:color=intensity:slide=1:scale=cbrt [out0]'
showspectrumpic
Convert input audio to a single video frame, representing the audio frequency spectrum.
The filter accepts the following options:
size, s
Specify the video size for the output. For the syntax of this option, check the "Video
size" section in the ffmpeg-utils manual. Default value is "4096x2048".
mode
Specify display mode.
It accepts the following values:
combined
all channels are displayed in the same row
separate
all channels are displayed in separate rows
Default value is combined.
color
Specify display color mode.
It accepts the following values:
channel
each channel is displayed in a separate color
intensity
each channel is displayed using the same color scheme
rainbow
each channel is displayed using the rainbow color scheme
moreland
each channel is displayed using the moreland color scheme
nebulae
each channel is displayed using the nebulae color scheme
fire
each channel is displayed using the fire color scheme
fiery
each channel is displayed using the fiery color scheme
fruit
each channel is displayed using the fruit color scheme
cool
each channel is displayed using the cool color scheme
magma
each channel is displayed using the magma color scheme
green
each channel is displayed using the green color scheme
viridis
each channel is displayed using the viridis color scheme
plasma
each channel is displayed using the plasma color scheme
cividis
each channel is displayed using the cividis color scheme
terrain
each channel is displayed using the terrain color scheme
Default value is intensity.
scale
Specify scale used for calculating intensity color values.
It accepts the following values:
lin linear
sqrt
square root, default
cbrt
cubic root
log logarithmic
4thrt
4th root
5thrt
5th root
Default value is log.
fscale
Specify frequency scale.
It accepts the following values:
lin linear
log logarithmic
Default value is lin.
saturation
Set saturation modifier for displayed colors. Negative values provide alternative
color scheme. 0 is no saturation at all. Saturation must be in [-10.0, 10.0] range.
Default value is 1.
win_func
Set window function.
It accepts the following values:
rect
bartlett
hann
hanning
hamming
blackman
welch
flattop
bharris
bnuttall
bhann
sine
nuttall
lanczos
gauss
tukey
dolph
cauchy
parzen
poisson
bohman
kaiser
Default value is "hann".
orientation
Set orientation of time vs frequency axis. Can be "vertical" or "horizontal". Default
is "vertical".
gain
Set scale gain for calculating intensity color values. Default value is 1.
legend
Draw time and frequency axes and legends. Default is enabled.
rotation
Set color rotation, must be in [-1.0, 1.0] range. Default value is 0.
start
Set start frequency from which to display spectrogram. Default is 0.
stop
Set stop frequency to which to display spectrogram. Default is 0.
drange
Set dynamic range used to calculate intensity color values. Default is 120 dBFS.
Allowed range is from 10 to 200.
limit
Set upper limit of input audio samples volume in dBFS. Default is 0 dBFS. Allowed
range is from -100 to 100.
opacity
Set opacity strength when using pixel format output with alpha component.
Examples
• Extract an audio spectrogram of a whole audio track in a 1024x1024 picture using
ffmpeg:
ffmpeg -i audio.flac -lavfi showspectrumpic=s=1024x1024 spectrogram.png
showvolume
Convert input audio volume to a video output.
The filter accepts the following options:
rate, r
Set video rate.
b Set border width, allowed range is [0, 5]. Default is 1.
w Set channel width, allowed range is [80, 8192]. Default is 400.
h Set channel height, allowed range is [1, 900]. Default is 20.
f Set fade, allowed range is [0, 1]. Default is 0.95.
c Set volume color expression.
The expression can use the following variables:
VOLUME
Current max volume of channel in dB.
PEAK
Current peak.
CHANNEL
Current channel number, starting from 0.
t If set, displays channel names. Default is enabled.
v If set, displays volume values. Default is enabled.
o Set orientation, can be horizontal: "h" or vertical: "v", default is "h".
s Set step size, allowed range is [0, 5]. Default is 0, which means step is disabled.
p Set background opacity, allowed range is [0, 1]. Default is 0.
m Set metering mode, can be peak: "p" or rms: "r", default is "p".
ds Set display scale, can be linear: "lin" or log: "log", default is "lin".
dm In second. If set to > 0., display a line for the max level in the previous seconds.
default is disabled: 0.
dmc The color of the max line. Use when "dm" option is set to > 0. default is: "orange"
showwaves
Convert input audio to a video output, representing the samples waves.
The filter accepts the following options:
size, s
Specify the video size for the output. For the syntax of this option, check the "Video
size" section in the ffmpeg-utils manual. Default value is "600x240".
mode
Set display mode.
Available values are:
point
Draw a point for each sample.
line
Draw a vertical line for each sample.
p2p Draw a point for each sample and a line between them.
cline
Draw a centered vertical line for each sample.
Default value is "point".
n Set the number of samples which are printed on the same column. A larger value will
decrease the frame rate. Must be a positive integer. This option can be set only if
the value for rate is not explicitly specified.
rate, r
Set the (approximate) output frame rate. This is done by setting the option n. Default
value is "25".
split_channels
Set if channels should be drawn separately or overlap. Default value is 0.
colors
Set colors separated by '|' which are going to be used for drawing of each channel.
scale
Set amplitude scale.
Available values are:
lin Linear.
log Logarithmic.
sqrt
Square root.
cbrt
Cubic root.
Default is linear.
draw
Set the draw mode. This is mostly useful to set for high n.
Available values are:
scale
Scale pixel values for each drawn sample.
full
Draw every sample directly.
Default value is "scale".
Examples
• Output the input file audio and the corresponding video representation at the same
time:
amovie=a.mp3,asplit[out0],showwaves[out1]
• Create a synthetic signal and show it with showwaves, forcing a frame rate of 30
frames per second:
aevalsrc=sin(1*2*PI*t)*sin(880*2*PI*t):cos(2*PI*200*t),asplit[out0],showwaves=r=30[out1]
showwavespic
Convert input audio to a single video frame, representing the samples waves.
The filter accepts the following options:
size, s
Specify the video size for the output. For the syntax of this option, check the "Video
size" section in the ffmpeg-utils manual. Default value is "600x240".
split_channels
Set if channels should be drawn separately or overlap. Default value is 0.
colors
Set colors separated by '|' which are going to be used for drawing of each channel.
scale
Set amplitude scale.
Available values are:
lin Linear.
log Logarithmic.
sqrt
Square root.
cbrt
Cubic root.
Default is linear.
draw
Set the draw mode.
Available values are:
scale
Scale pixel values for each drawn sample.
full
Draw every sample directly.
Default value is "scale".
filter
Set the filter mode.
Available values are:
average
Use average samples values for each drawn sample.
peak
Use peak samples values for each drawn sample.
Default value is "average".
Examples
• Extract a channel split representation of the wave form of a whole audio track in a
1024x800 picture using ffmpeg:
ffmpeg -i audio.flac -lavfi showwavespic=split_channels=1:s=1024x800 waveform.png
sidedata, asidedata
Delete frame side data, or select frames based on it.
This filter accepts the following options:
mode
Set mode of operation of the filter.
Can be one of the following:
select
Select every frame with side data of "type".
delete
Delete side data of "type". If "type" is not set, delete all side data in the
frame.
type
Set side data type used with all modes. Must be set for "select" mode. For the list of
frame side data types, refer to the "AVFrameSideDataType" enum in libavutil/frame.h.
For example, to choose "AV_FRAME_DATA_PANSCAN" side data, you must specify "PANSCAN".
spectrumsynth
Synthesize audio from 2 input video spectrums, first input stream represents magnitude
across time and second represents phase across time. The filter will transform from
frequency domain as displayed in videos back to time domain as presented in audio output.
This filter is primarily created for reversing processed showspectrum filter outputs, but
can synthesize sound from other spectrograms too. But in such case results are going to
be poor if the phase data is not available, because in such cases phase data need to be
recreated, usually it's just recreated from random noise. For best results use gray only
output ("channel" color mode in showspectrum filter) and "log" scale for magnitude video
and "lin" scale for phase video. To produce phase, for 2nd video, use "data" option.
Inputs videos should generally use "fullframe" slide mode as that saves resources needed
for decoding video.
The filter accepts the following options:
sample_rate
Specify sample rate of output audio, the sample rate of audio from which spectrum was
generated may differ.
channels
Set number of channels represented in input video spectrums.
scale
Set scale which was used when generating magnitude input spectrum. Can be "lin" or
"log". Default is "log".
slide
Set slide which was used when generating inputs spectrums. Can be "replace",
"scroll", "fullframe" or "rscroll". Default is "fullframe".
win_func
Set window function used for resynthesis.
overlap
Set window overlap. In range "[0, 1]". Default is 1, which means optimal overlap for
selected window function will be picked.
orientation
Set orientation of input videos. Can be "vertical" or "horizontal". Default is
"vertical".
Examples
• First create magnitude and phase videos from audio, assuming audio is stereo with
44100 sample rate, then resynthesize videos back to audio with spectrumsynth:
ffmpeg -i input.flac -lavfi showspectrum=mode=separate:scale=log:overlap=0.875:color=channel:slide=fullframe:data=magnitude -an -c:v rawvideo magnitude.nut
ffmpeg -i input.flac -lavfi showspectrum=mode=separate:scale=lin:overlap=0.875:color=channel:slide=fullframe:data=phase -an -c:v rawvideo phase.nut
ffmpeg -i magnitude.nut -i phase.nut -lavfi spectrumsynth=channels=2:sample_rate=44100:win_func=hann:overlap=0.875:slide=fullframe output.flac
split, asplit
Split input into several identical outputs.
"asplit" works with audio input, "split" with video.
The filter accepts a single parameter which specifies the number of outputs. If
unspecified, it defaults to 2.
Examples
• Create two separate outputs from the same input:
[in] split [out0][out1]
• To create 3 or more outputs, you need to specify the number of outputs, like in:
[in] asplit=3 [out0][out1][out2]
• Create two separate outputs from the same input, one cropped and one padded:
[in] split [splitout1][splitout2];
[splitout1] crop=100:100:0:0 [cropout];
[splitout2] pad=200:200:100:100 [padout];
• Create 5 copies of the input audio with ffmpeg:
ffmpeg -i INPUT -filter_complex asplit=5 OUTPUT
zmq, azmq
Receive commands sent through a libzmq client, and forward them to filters in the
filtergraph.
"zmq" and "azmq" work as a pass-through filters. "zmq" must be inserted between two video
filters, "azmq" between two audio filters. Both are capable to send messages to any filter
type.
To enable these filters you need to install the libzmq library and headers and configure
FFmpeg with "--enable-libzmq".
For more information about libzmq see: <http://www.zeromq.org/>
The "zmq" and "azmq" filters work as a libzmq server, which receives messages sent through
a network interface defined by the bind_address (or the abbreviation "b") option. Default
value of this option is tcp://localhost:5555. You may want to alter this value to your
needs, but do not forget to escape any ':' signs (see filtergraph escaping).
The received message must be in the form:
<TARGET> <COMMAND> [<ARG>]
TARGET specifies the target of the command, usually the name of the filter class or a
specific filter instance name. The default filter instance name uses the pattern
Parsed_<filter_name>_<index>, but you can override this by using the filter_name@id syntax
(see Filtergraph syntax).
COMMAND specifies the name of the command for the target filter.
ARG is optional and specifies the optional argument list for the given COMMAND.
Upon reception, the message is processed and the corresponding command is injected into
the filtergraph. Depending on the result, the filter will send a reply to the client,
adopting the format:
<ERROR_CODE> <ERROR_REASON>
<MESSAGE>
MESSAGE is optional.
Examples
Look at tools/zmqsend for an example of a zmq client which can be used to send commands
processed by these filters.
Consider the following filtergraph generated by ffplay. In this example the last overlay
filter has an instance name. All other filters will have default instance names.
ffplay -dumpgraph 1 -f lavfi "
color=s=100x100:c=red [l];
color=s=100x100:c=blue [r];
nullsrc=s=200x100, zmq [bg];
[bg][l] overlay [bg+l];
[bg+l][r] overlay@my=x=100 "
To change the color of the left side of the video, the following command can be used:
echo Parsed_color_0 c yellow | tools/zmqsend
To change the right side:
echo Parsed_color_1 c pink | tools/zmqsend
To change the position of the right side:
echo overlay@my x 150 | tools/zmqsend
MULTIMEDIA SOURCES
Below is a description of the currently available multimedia sources.
amovie
This is the same as movie source, except it selects an audio stream by default.
avsynctest
Generate an Audio/Video Sync Test.
Generated stream periodically shows flash video frame and emits beep in audio. Useful to
inspect A/V sync issues.
It accepts the following options:
size, s
Set output video size. Default value is "hd720".
framerate, fr
Set output video frame rate. Default value is 30.
samplerate, sr
Set output audio sample rate. Default value is 44100.
amplitude, a
Set output audio beep amplitude. Default value is 0.7.
period, p
Set output audio beep period in seconds. Default value is 3.
delay, dl
Set output video flash delay in number of frames. Default value is 0.
cycle, c
Enable cycling of video delays, by default is disabled.
duration, d
Set stream output duration. By default duration is unlimited.
fg, bg, ag
Set foreground/background/additional color.
Commands
This source supports the some above options as commands.
movie
Read audio and/or video stream(s) from a movie container.
It accepts the following parameters:
filename
The name of the resource to read (not necessarily a file; it can also be a device or a
stream accessed through some protocol).
format_name, f
Specifies the format assumed for the movie to read, and can be either the name of a
container or an input device. If not specified, the format is guessed from movie_name
or by probing.
seek_point, sp
Specifies the seek point in seconds. The frames will be output starting from this seek
point. The parameter is evaluated with "av_strtod", so the numerical value may be
suffixed by an IS postfix. The default value is "0".
streams, s
Specifies the streams to read. Several streams can be specified, separated by "+". The
source will then have as many outputs, in the same order. The syntax is explained in
the "Stream specifiers" section in the ffmpeg manual. Two special names, "dv" and "da"
specify respectively the default (best suited) video and audio stream. Default is
"dv", or "da" if the filter is called as "amovie".
stream_index, si
Specifies the index of the video stream to read. If the value is -1, the most suitable
video stream will be automatically selected. The default value is "-1". Deprecated. If
the filter is called "amovie", it will select audio instead of video.
loop
Specifies how many times to read the stream in sequence. If the value is 0, the
stream will be looped infinitely. Default value is "1".
Note that when the movie is looped the source timestamps are not changed, so it will
generate non monotonically increasing timestamps.
discontinuity
Specifies the time difference between frames above which the point is considered a
timestamp discontinuity which is removed by adjusting the later timestamps.
dec_threads
Specifies the number of threads for decoding
format_opts
Specify format options for the opened file. Format options can be specified as a list
of key=value pairs separated by ':'. The following example shows how to add
protocol_whitelist and protocol_blacklist options:
ffplay -f lavfi
"movie=filename='1.sdp':format_opts='protocol_whitelist=file,rtp,udp\:protocol_blacklist=http'"
It allows overlaying a second video on top of the main input of a filtergraph, as shown in
this graph:
input -----------> deltapts0 --> overlay --> output
^
|
movie --> scale--> deltapts1 -------+
Examples
• Skip 3.2 seconds from the start of the AVI file in.avi, and overlay it on top of the
input labelled "in":
movie=in.avi:seek_point=3.2, scale=180:-1, setpts=PTS-STARTPTS [over];
[in] setpts=PTS-STARTPTS [main];
[main][over] overlay=16:16 [out]
• Read from a video4linux2 device, and overlay it on top of the input labelled "in":
movie=/dev/video0:f=video4linux2, scale=180:-1, setpts=PTS-STARTPTS [over];
[in] setpts=PTS-STARTPTS [main];
[main][over] overlay=16:16 [out]
• Read the first video stream and the audio stream with id 0x81 from dvd.vob; the video
is connected to the pad named "video" and the audio is connected to the pad named
"audio":
movie=dvd.vob:s=v:0+#0x81 [video] [audio]
Commands
Both movie and amovie support the following commands:
seek
Perform seek using "av_seek_frame". The syntax is: seek stream_index|timestamp|flags
• stream_index: If stream_index is -1, a default stream is selected, and timestamp
is automatically converted from AV_TIME_BASE units to the stream specific
time_base.
• timestamp: Timestamp in AVStream.time_base units or, if no stream is specified, in
AV_TIME_BASE units.
• flags: Flags which select direction and seeking mode.
get_duration
Get movie duration in AV_TIME_BASE units.
EXTERNAL LIBRARIES
FFmpeg can be hooked up with a number of external libraries to add support for more
formats. None of them are used by default, their use has to be explicitly requested by
passing the appropriate flags to ./configure.
Alliance for Open Media (AOM)
FFmpeg can make use of the AOM library for AV1 decoding and encoding.
Go to <http://aomedia.org/> and follow the instructions for installing the library. Then
pass "--enable-libaom" to configure to enable it.
AMD AMF/VCE
FFmpeg can use the AMD Advanced Media Framework library for accelerated H.264 and
HEVC(only windows) encoding on hardware with Video Coding Engine (VCE).
To enable support you must obtain the AMF framework header files(version 1.4.9+) from
<https://github.com/GPUOpen-LibrariesAndSDKs/AMF.git>.
Create an "AMF/" directory in the system include path. Copy the contents of
"AMF/amf/public/include/" into that directory. Then configure FFmpeg with "--enable-amf".
Initialization of amf encoder occurs in this order: 1) trying to initialize through
dx11(only windows) 2) trying to initialize through dx9(only windows) 3) trying to
initialize through vulkan
To use h.264(AMD VCE) encoder on linux amdgru-pro version 19.20+ and amf-amdgpu-pro
package(amdgru-pro contains, but does not install automatically) are required.
This driver can be installed using amdgpu-pro-install script in official amd driver
archive.
AviSynth
FFmpeg can read AviSynth scripts as input. To enable support, pass "--enable-avisynth" to
configure after installing the headers provided by
<https://github.com/AviSynth/AviSynthPlus>. AviSynth+ can be configured to install only
the headers by either passing "-DHEADERS_ONLY:bool=on" to the normal CMake-based build
system, or by using the supplied "GNUmakefile".
For Windows, supported AviSynth variants are <http://avisynth.nl> for 32-bit builds and
<http://avisynth.nl/index.php/AviSynth+> for 32-bit and 64-bit builds.
For Linux, macOS, and BSD, the only supported AviSynth variant is
<https://github.com/AviSynth/AviSynthPlus>, starting with version 3.5.
In 2016, AviSynth+ added support for building with GCC. However, due to the
eccentricities of Windows' calling conventions, 32-bit GCC builds of AviSynth+ are not
compatible with typical 32-bit builds of FFmpeg.
By default, FFmpeg assumes compatibility with 32-bit MSVC builds of AviSynth+ since
that is the most widely-used and entrenched build configuration. Users can override
this and enable support for 32-bit GCC builds of AviSynth+ by passing
"-DAVSC_WIN32_GCC32" to "--extra-cflags" when configuring FFmpeg.
64-bit builds of FFmpeg are not affected, and can use either MSVC or GCC builds of
AviSynth+ without any special flags.
AviSynth(+) is loaded dynamically. Distributors can build FFmpeg with
"--enable-avisynth", and the binaries will work regardless of the end user having
AviSynth installed. If/when an end user would like to use AviSynth scripts, then they
can install AviSynth(+) and FFmpeg will be able to find and use it to open scripts.
Chromaprint
FFmpeg can make use of the Chromaprint library for generating audio fingerprints. Pass
"--enable-chromaprint" to configure to enable it. See <https://acoustid.org/chromaprint>.
codec2
FFmpeg can make use of the codec2 library for codec2 decoding and encoding. There is
currently no native decoder, so libcodec2 must be used for decoding.
Go to <http://freedv.org/>, download "Codec 2 source archive". Build and install using
CMake. Debian users can install the libcodec2-dev package instead. Once libcodec2 is
installed you can pass "--enable-libcodec2" to configure to enable it.
The easiest way to use codec2 is with .c2 files, since they contain the mode information
required for decoding. To encode such a file, use a .c2 file extension and give the
libcodec2 encoder the -mode option: "ffmpeg -i input.wav -mode 700C output.c2". Playback
is as simple as "ffplay output.c2". For a list of supported modes, run "ffmpeg -h
encoder=libcodec2". Raw codec2 files are also supported. To make sense of them the mode
in use needs to be specified as a format option: "ffmpeg -f codec2raw -mode 1300 -i
input.raw output.wav".
dav1d
FFmpeg can make use of the dav1d library for AV1 video decoding.
Go to <https://code.videolan.org/videolan/dav1d> and follow the instructions for
installing the library. Then pass "--enable-libdav1d" to configure to enable it.
davs2
FFmpeg can make use of the davs2 library for AVS2-P2/IEEE1857.4 video decoding.
Go to <https://github.com/pkuvcl/davs2> and follow the instructions for installing the
library. Then pass "--enable-libdavs2" to configure to enable it.
libdavs2 is under the GNU Public License Version 2 or later (see
<http://www.gnu.org/licenses/old-licenses/gpl-2.0.html> for details), you must upgrade
FFmpeg's license to GPL in order to use it.
uavs3d
FFmpeg can make use of the uavs3d library for AVS3-P2/IEEE1857.10 video decoding.
Go to <https://github.com/uavs3/uavs3d> and follow the instructions for installing the
library. Then pass "--enable-libuavs3d" to configure to enable it.
Game Music Emu
FFmpeg can make use of the Game Music Emu library to read audio from supported video game
music file formats. Pass "--enable-libgme" to configure to enable it. See
<https://bitbucket.org/mpyne/game-music-emu/overview>.
Intel QuickSync Video
FFmpeg can use Intel QuickSync Video (QSV) for accelerated decoding and encoding of
multiple codecs. To use QSV, FFmpeg must be linked against the "libmfx" dispatcher, which
loads the actual decoding libraries.
The dispatcher is open source and can be downloaded from
<https://github.com/lu-zero/mfx_dispatch.git>. FFmpeg needs to be configured with the
"--enable-libmfx" option and "pkg-config" needs to be able to locate the dispatcher's
".pc" files.
Kvazaar
FFmpeg can make use of the Kvazaar library for HEVC encoding.
Go to <https://github.com/ultravideo/kvazaar> and follow the instructions for installing
the library. Then pass "--enable-libkvazaar" to configure to enable it.
LAME
FFmpeg can make use of the LAME library for MP3 encoding.
Go to <http://lame.sourceforge.net/> and follow the instructions for installing the
library. Then pass "--enable-libmp3lame" to configure to enable it.
LCEVCdec
FFmpeg can make use of the liblcevc_dec library for LCEVC enhacement layer decoding on
supported bitstreams.
Go to <https://github.com/v-novaltd/LCEVCdec> and follow the instructions for installing
the library. Then pass "--enable-liblcevc-dec" to configure to enable it.
LCEVCdec is under the BSD-3-Clause-Clear License.
libilbc
iLBC is a narrowband speech codec that has been made freely available by Google as part of
the WebRTC project. libilbc is a packaging friendly copy of the iLBC codec. FFmpeg can
make use of the libilbc library for iLBC decoding and encoding.
Go to <https://github.com/TimothyGu/libilbc> and follow the instructions for installing
the library. Then pass "--enable-libilbc" to configure to enable it.
libjxl
JPEG XL is an image format intended to fully replace legacy JPEG for an extended period of
life. See <https://jpegxl.info/> for more information, and see
<https://github.com/libjxl/libjxl> for the library source. You can pass "--enable-libjxl"
to configure in order enable the libjxl wrapper.
libvpx
FFmpeg can make use of the libvpx library for VP8/VP9 decoding and encoding.
Go to <http://www.webmproject.org/> and follow the instructions for installing the
library. Then pass "--enable-libvpx" to configure to enable it.
ModPlug
FFmpeg can make use of this library, originating in Modplug-XMMS, to read from MOD-like
music files. See <https://github.com/Konstanty/libmodplug>. Pass "--enable-libmodplug" to
configure to enable it.
OpenCORE, VisualOn, and Fraunhofer libraries
Spun off Google Android sources, OpenCore, VisualOn and Fraunhofer libraries provide
encoders for a number of audio codecs.
OpenCORE and VisualOn libraries are under the Apache License 2.0 (see
<http://www.apache.org/licenses/LICENSE-2.0> for details), which is incompatible to
the LGPL version 2.1 and GPL version 2. You have to upgrade FFmpeg's license to LGPL
version 3 (or if you have enabled GPL components, GPL version 3) by passing
"--enable-version3" to configure in order to use it.
The license of the Fraunhofer AAC library is incompatible with the GPL. Therefore,
for GPL builds, you have to pass "--enable-nonfree" to configure in order to use it.
To the best of our knowledge, it is compatible with the LGPL.
OpenCORE AMR
FFmpeg can make use of the OpenCORE libraries for AMR-NB decoding/encoding and AMR-WB
decoding.
Go to <http://sourceforge.net/projects/opencore-amr/> and follow the instructions for
installing the libraries. Then pass "--enable-libopencore-amrnb" and/or
"--enable-libopencore-amrwb" to configure to enable them.
VisualOn AMR-WB encoder library
FFmpeg can make use of the VisualOn AMR-WBenc library for AMR-WB encoding.
Go to <http://sourceforge.net/projects/opencore-amr/> and follow the instructions for
installing the library. Then pass "--enable-libvo-amrwbenc" to configure to enable it.
Fraunhofer AAC library
FFmpeg can make use of the Fraunhofer AAC library for AAC decoding & encoding.
Go to <http://sourceforge.net/projects/opencore-amr/> and follow the instructions for
installing the library. Then pass "--enable-libfdk-aac" to configure to enable it.
LC3 library
FFmpeg can make use of the Google LC3 library for LC3 decoding & encoding.
Go to <https://github.com/google/liblc3/> and follow the instructions for installing the
library. Then pass "--enable-liblc3" to configure to enable it.
OpenH264
FFmpeg can make use of the OpenH264 library for H.264 decoding and encoding.
Go to <http://www.openh264.org/> and follow the instructions for installing the library.
Then pass "--enable-libopenh264" to configure to enable it.
For decoding, this library is much more limited than the built-in decoder in libavcodec;
currently, this library lacks support for decoding B-frames and some other main/high
profile features. (It currently only supports constrained baseline profile and CABAC.)
Using it is mostly useful for testing and for taking advantage of Cisco's patent portfolio
license (<http://www.openh264.org/BINARY_LICENSE.txt>).
OpenJPEG
FFmpeg can use the OpenJPEG libraries for decoding/encoding J2K videos. Go to
<http://www.openjpeg.org/> to get the libraries and follow the installation instructions.
To enable using OpenJPEG in FFmpeg, pass "--enable-libopenjpeg" to ./configure.
rav1e
FFmpeg can make use of rav1e (Rust AV1 Encoder) via its C bindings to encode videos. Go
to <https://github.com/xiph/rav1e/> and follow the instructions to build the C library. To
enable using rav1e in FFmpeg, pass "--enable-librav1e" to ./configure.
SVT-AV1
FFmpeg can make use of the Scalable Video Technology for AV1 library for AV1 encoding.
Go to <https://gitlab.com/AOMediaCodec/SVT-AV1/> and follow the instructions for
installing the library. Then pass "--enable-libsvtav1" to configure to enable it.
TwoLAME
FFmpeg can make use of the TwoLAME library for MP2 encoding.
Go to <http://www.twolame.org/> and follow the instructions for installing the library.
Then pass "--enable-libtwolame" to configure to enable it.
VapourSynth
FFmpeg can read VapourSynth scripts as input. To enable support, pass
"--enable-vapoursynth" to configure. Vapoursynth is detected via "pkg-config". Versions 42
or greater supported. See <http://www.vapoursynth.com/>.
Due to security concerns, Vapoursynth scripts will not be autodetected so the input format
has to be forced. For ff* CLI tools, add "-f vapoursynth" before the input "-i
yourscript.vpy".
x264
FFmpeg can make use of the x264 library for H.264 encoding.
Go to <http://www.videolan.org/developers/x264.html> and follow the instructions for
installing the library. Then pass "--enable-libx264" to configure to enable it.
x264 is under the GNU Public License Version 2 or later (see
<http://www.gnu.org/licenses/old-licenses/gpl-2.0.html> for details), you must upgrade
FFmpeg's license to GPL in order to use it.
x265
FFmpeg can make use of the x265 library for HEVC encoding.
Go to <http://x265.org/developers.html> and follow the instructions for installing the
library. Then pass "--enable-libx265" to configure to enable it.
x265 is under the GNU Public License Version 2 or later (see
<http://www.gnu.org/licenses/old-licenses/gpl-2.0.html> for details), you must upgrade
FFmpeg's license to GPL in order to use it.
xavs
FFmpeg can make use of the xavs library for AVS encoding.
Go to <http://xavs.sf.net/> and follow the instructions for installing the library. Then
pass "--enable-libxavs" to configure to enable it.
xavs2
FFmpeg can make use of the xavs2 library for AVS2-P2/IEEE1857.4 video encoding.
Go to <https://github.com/pkuvcl/xavs2> and follow the instructions for installing the
library. Then pass "--enable-libxavs2" to configure to enable it.
libxavs2 is under the GNU Public License Version 2 or later (see
<http://www.gnu.org/licenses/old-licenses/gpl-2.0.html> for details), you must upgrade
FFmpeg's license to GPL in order to use it.
eXtra-fast Essential Video Encoder (XEVE)
FFmpeg can make use of the XEVE library for EVC video encoding.
Go to <https://github.com/mpeg5/xeve> and follow the instructions for installing the XEVE
library. Then pass "--enable-libxeve" to configure to enable it.
eXtra-fast Essential Video Decoder (XEVD)
FFmpeg can make use of the XEVD library for EVC video decoding.
Go to <https://github.com/mpeg5/xevd> and follow the instructions for installing the XEVD
library. Then pass "--enable-libxevd" to configure to enable it.
ZVBI
ZVBI is a VBI decoding library which can be used by FFmpeg to decode DVB teletext pages
and DVB teletext subtitles.
Go to <http://sourceforge.net/projects/zapping/> and follow the instructions for
installing the library. Then pass "--enable-libzvbi" to configure to enable it.
SUPPORTED FILE FORMATS
You can use the "-formats" and "-codecs" options to have an exhaustive list.
File Formats
FFmpeg supports the following file formats through the "libavformat" library:
Name : Encoding @tab Decoding @tab Comments
3dostr : @tab X
4xm : @tab X
@tab 4X Technologies format, used in some games.
8088flex TMV : @tab X
AAX : @tab X
@tab Audible Enhanced Audio format, used in audiobooks.
AA : @tab X
@tab Audible Format 2, 3, and 4, used in audiobooks.
ACT Voice : @tab X
@tab contains G.729 audio
Adobe Filmstrip : X @tab X
Audio IFF (AIFF) : X @tab X
American Laser Games MM : @tab X
@tab Multimedia format used in games like Mad Dog McCree.
3GPP AMR : X @tab X
Amazing Studio Packed Animation File : @tab X
@tab Multimedia format used in game Heart Of Darkness.
Apple HTTP Live Streaming : @tab X
Artworx Data Format : @tab X
Interplay ACM : @tab X
@tab Audio only format used in some Interplay games.
ADP : @tab X
@tab Audio format used on the Nintendo Gamecube.
AFC : @tab X
@tab Audio format used on the Nintendo Gamecube.
ADS/SS2 : @tab X
@tab Audio format used on the PS2.
APNG : X @tab X
ASF : X @tab X
@tab Advanced / Active Streaming Format.
AST : X @tab X
@tab Audio format used on the Nintendo Wii.
AVI : X @tab X
AviSynth : @tab X
AVR : @tab X
@tab Audio format used on Mac.
AVS : @tab X
@tab Multimedia format used by the Creature Shock game.
Beam Software SIFF : @tab X
@tab Audio and video format used in some games by Beam Software.
Bethesda Softworks VID : @tab X
@tab Used in some games from Bethesda Softworks.
Binary text : @tab X
Bink : @tab X
@tab Multimedia format used by many games.
Bink Audio : @tab X
@tab Audio only multimedia format used by some games.
Bitmap Brothers JV : @tab X
@tab Used in Z and Z95 games.
BRP : @tab X
@tab Argonaut Games format.
Brute Force & Ignorance : @tab X
@tab Used in the game Flash Traffic: City of Angels.
BFSTM : @tab X
@tab Audio format used on the Nintendo WiiU (based on BRSTM).
BRSTM : @tab X
@tab Audio format used on the Nintendo Wii.
BW64 : @tab X
@tab Broadcast Wave 64bit.
BWF : X @tab X
codec2 (raw) : X @tab X
@tab Must be given -mode format option to decode correctly.
codec2 (.c2 files) : X @tab X
@tab Contains header with version and mode info, simplifying playback.
CRI ADX : X @tab X
@tab Audio-only format used in console video games.
CRI AIX : @tab X
CRI HCA : @tab X
@tab Audio-only format used in console video games.
Discworld II BMV : @tab X
Interplay C93 : @tab X
@tab Used in the game Cyberia from Interplay.
Delphine Software International CIN : @tab X
@tab Multimedia format used by Delphine Software games.
Digital Speech Standard (DSS) : @tab X
CD+G : @tab X
@tab Video format used by CD+G karaoke disks
Phantom Cine : @tab X
Commodore CDXL : @tab X
@tab Amiga CD video format
Core Audio Format : X @tab X
@tab Apple Core Audio Format
CRC testing format : X @tab
Creative Voice : X @tab X
@tab Created for the Sound Blaster Pro.
CRYO APC : @tab X
@tab Audio format used in some games by CRYO Interactive Entertainment.
D-Cinema audio : X @tab X
Deluxe Paint Animation : @tab X
DCSTR : @tab X
DFA : @tab X
@tab This format is used in Chronomaster game
DirectDraw Surface : @tab X
DSD Stream File (DSF) : @tab X
DV video : X @tab X
DXA : @tab X
@tab This format is used in the non-Windows version of the Feeble Files
game and different game cutscenes repacked for use with ScummVM.
Electronic Arts cdata : @tab X
Electronic Arts Multimedia : @tab X
@tab Used in various EA games; files have extensions like WVE and UV2.
Ensoniq Paris Audio File : @tab X
FFM (FFserver live feed) : X @tab X
Flash (SWF) : X @tab X
Flash 9 (AVM2) : X @tab X
@tab Only embedded audio is decoded.
FLI/FLC/FLX animation : @tab X
@tab .fli/.flc files
Flash Video (FLV) : X @tab X
@tab Macromedia Flash video files
framecrc testing format : X @tab
FunCom ISS : @tab X
@tab Audio format used in various games from FunCom like The Longest Journey.
G.723.1 : X @tab X
G.726 : @tab X @tab Both left- and right-justified.
G.729 BIT : X @tab X
G.729 raw : @tab X
GENH : @tab X
@tab Audio format for various games.
GIF Animation : X @tab X
GXF : X @tab X
@tab General eXchange Format SMPTE 360M, used by Thomson Grass Valley
playout servers.
HNM : @tab X
@tab Only version 4 supported, used in some games from Cryo Interactive
iCEDraw File : @tab X
ICO : X @tab X
@tab Microsoft Windows ICO
id Quake II CIN video : @tab X
id RoQ : X @tab X
@tab Used in Quake III, Jedi Knight 2 and other computer games.
IEC61937 encapsulation : X @tab X
IFF : @tab X
@tab Interchange File Format
IFV : @tab X
@tab A format used by some old CCTV DVRs.
iLBC : X @tab X
Interplay MVE : @tab X
@tab Format used in various Interplay computer games.
Iterated Systems ClearVideo : @tab X
@tab I-frames only
IV8 : @tab X
@tab A format generated by IndigoVision 8000 video server.
IVF (On2) : X @tab X
@tab A format used by libvpx
Internet Video Recording : @tab X
IRCAM : X @tab X
LAF : @tab X
@tab Limitless Audio Format
LATM : X @tab X
LMLM4 : @tab X
@tab Used by Linux Media Labs MPEG-4 PCI boards
LOAS : @tab X
@tab contains LATM multiplexed AAC audio
LRC : X @tab X
LVF : @tab X
LXF : @tab X
@tab VR native stream format, used by Leitch/Harris' video servers.
Magic Lantern Video (MLV) : @tab X
Matroska : X @tab X
Matroska audio : X @tab
FFmpeg metadata : X @tab X
@tab Metadata in text format.
MAXIS XA : @tab X
@tab Used in Sim City 3000; file extension .xa.
MCA : @tab X
@tab Used in some games from Capcom; file extension .mca.
MD Studio : @tab X
Metal Gear Solid: The Twin Snakes : @tab X
Megalux Frame : @tab X
@tab Used by Megalux Ultimate Paint
MobiClip MODS : @tab X
MobiClip MOFLEX : @tab X
Mobotix .mxg : @tab X
Monkey's Audio : @tab X
Motion Pixels MVI : @tab X
MOV/QuickTime/MP4 : X @tab X
@tab 3GP, 3GP2, PSP, iPod variants supported
MP2 : X @tab X
MP3 : X @tab X
MPEG-1 System : X @tab X
@tab muxed audio and video, VCD format supported
MPEG-PS (program stream) : X @tab X
@tab also known as C<VOB> file, SVCD and DVD format supported
MPEG-TS (transport stream) : X @tab X
@tab also known as DVB Transport Stream
MPEG-4 : X @tab X
@tab MPEG-4 is a variant of QuickTime.
MSF : @tab X
@tab Audio format used on the PS3.
Mirillis FIC video : @tab X
@tab No cursor rendering.
MIDI Sample Dump Standard : @tab X
MIME multipart JPEG : X @tab
MSN TCP webcam : @tab X
@tab Used by MSN Messenger webcam streams.
MTV : @tab X
Musepack : @tab X
Musepack SV8 : @tab X
Material eXchange Format (MXF) : X @tab X
@tab SMPTE 377M, used by D-Cinema, broadcast industry.
Material eXchange Format (MXF), D-10 Mapping : X @tab X
@tab SMPTE 386M, D-10/IMX Mapping.
NC camera feed : @tab X
@tab NC (AVIP NC4600) camera streams
NIST SPeech HEader REsources : @tab X
Computerized Speech Lab NSP : @tab X
NTT TwinVQ (VQF) : @tab X
@tab Nippon Telegraph and Telephone Corporation TwinVQ.
Nullsoft Streaming Video : @tab X
NuppelVideo : @tab X
NUT : X @tab X
@tab NUT Open Container Format
Ogg : X @tab X
Playstation Portable PMP : @tab X
Portable Voice Format : @tab X
RK Audio (RKA) : @tab X
TechnoTrend PVA : @tab X
@tab Used by TechnoTrend DVB PCI boards.
QCP : @tab X
raw ADTS (AAC) : X @tab X
raw AC-3 : X @tab X
raw AMR-NB : @tab X
raw AMR-WB : @tab X
raw APAC : @tab X
raw aptX : X @tab X
raw aptX HD : X @tab X
raw Bonk : @tab X
raw Chinese AVS video : X @tab X
raw DFPWM : X @tab X
raw Dirac : X @tab X
raw DNxHD : X @tab X
raw DTS : X @tab X
raw DTS-HD : @tab X
raw E-AC-3 : X @tab X
raw EVC : X @tab X
raw FLAC : X @tab X
raw GSM : @tab X
raw H.261 : X @tab X
raw H.263 : X @tab X
raw H.264 : X @tab X
raw HEVC : X @tab X
raw Ingenient MJPEG : @tab X
raw MJPEG : X @tab X
raw MLP : @tab X
raw MPEG : @tab X
raw MPEG-1 : @tab X
raw MPEG-2 : @tab X
raw MPEG-4 : X @tab X
raw NULL : X @tab
raw video : X @tab X
raw id RoQ : X @tab
raw OBU : X @tab X
raw OSQ : @tab X
raw SBC : X @tab X
raw Shorten : @tab X
raw TAK : @tab X
raw TrueHD : X @tab X
raw VC-1 : X @tab X
raw PCM A-law : X @tab X
raw PCM mu-law : X @tab X
raw PCM Archimedes VIDC : X @tab X
raw PCM signed 8 bit : X @tab X
raw PCM signed 16 bit big-endian : X @tab X
raw PCM signed 16 bit little-endian : X @tab X
raw PCM signed 24 bit big-endian : X @tab X
raw PCM signed 24 bit little-endian : X @tab X
raw PCM signed 32 bit big-endian : X @tab X
raw PCM signed 32 bit little-endian : X @tab X
raw PCM signed 64 bit big-endian : X @tab X
raw PCM signed 64 bit little-endian : X @tab X
raw PCM unsigned 8 bit : X @tab X
raw PCM unsigned 16 bit big-endian : X @tab X
raw PCM unsigned 16 bit little-endian : X @tab X
raw PCM unsigned 24 bit big-endian : X @tab X
raw PCM unsigned 24 bit little-endian : X @tab X
raw PCM unsigned 32 bit big-endian : X @tab X
raw PCM unsigned 32 bit little-endian : X @tab X
raw PCM 16.8 floating point little-endian : @tab X
raw PCM 24.0 floating point little-endian : @tab X
raw PCM floating-point 32 bit big-endian : X @tab X
raw PCM floating-point 32 bit little-endian : X @tab X
raw PCM floating-point 64 bit big-endian : X @tab X
raw PCM floating-point 64 bit little-endian : X @tab X
RDT : @tab X
REDCODE R3D : @tab X
@tab File format used by RED Digital cameras, contains JPEG 2000 frames and PCM audio.
RealMedia : X @tab X
Redirector : @tab X
RedSpark : @tab X
Renderware TeXture Dictionary : @tab X
Resolume DXV : X @tab X
@tab Encoding is only supported for the DXT1 (Normal Quality, No Alpha) texture format.
RF64 : @tab X
RL2 : @tab X
@tab Audio and video format used in some games by Entertainment Software Partners.
RPL/ARMovie : @tab X
Lego Mindstorms RSO : X @tab X
RSD : @tab X
RTMP : X @tab X
@tab Output is performed by publishing stream to RTMP server
RTP : X @tab X
RTSP : X @tab X
Sample Dump eXchange : @tab X
SAP : X @tab X
SBG : @tab X
SDNS : @tab X
SDP : @tab X
SER : @tab X
Digital Pictures SGA : @tab X
Sega FILM/CPK : X @tab X
@tab Used in many Sega Saturn console games.
Silicon Graphics Movie : @tab X
Sierra SOL : @tab X
@tab .sol files used in Sierra Online games.
Sierra VMD : @tab X
@tab Used in Sierra CD-ROM games.
Smacker : @tab X
@tab Multimedia format used by many games.
SMJPEG : X @tab X
@tab Used in certain Loki game ports.
SMPTE 337M encapsulation : @tab X
Smush : @tab X
@tab Multimedia format used in some LucasArts games.
Sony OpenMG (OMA) : X @tab X
@tab Audio format used in Sony Sonic Stage and Sony Vegas.
Sony PlayStation STR : @tab X
Sony Wave64 (W64) : X @tab X
SoX native format : X @tab X
SUN AU format : X @tab X
SUP raw PGS subtitles : X @tab X
SVAG : @tab X
@tab Audio format used in Konami PS2 games.
TDSC : @tab X
Text files : @tab X
THP : @tab X
@tab Used on the Nintendo GameCube.
Tiertex Limited SEQ : @tab X
@tab Tiertex .seq files used in the DOS CD-ROM version of the game Flashback.
True Audio : X @tab X
VAG : @tab X
@tab Audio format used in many Sony PS2 games.
VC-1 test bitstream : X @tab X
Vidvox Hap : X @tab X
Vivo : @tab X
VPK : @tab X
@tab Audio format used in Sony PS games.
Marble WADY : @tab X
WAV : X @tab X
Waveform Archiver : @tab X
WavPack : X @tab X
WebM : X @tab X
Windows Televison (WTV) : X @tab X
Wing Commander III movie : @tab X
@tab Multimedia format used in Origin's Wing Commander III computer game.
Westwood Studios audio : X @tab X
@tab Multimedia format used in Westwood Studios games.
Westwood Studios VQA : @tab X
@tab Multimedia format used in Westwood Studios games.
Wideband Single-bit Data (WSD) : @tab X
WVE : @tab X
Konami XMD : @tab X
XMV : @tab X
@tab Microsoft video container used in Xbox games.
XVAG : @tab X
@tab Audio format used on the PS3.
xWMA : @tab X
@tab Microsoft audio container used by XAudio 2.
eXtended BINary text (XBIN) : @tab X
YUV4MPEG pipe : X @tab X
Psygnosis YOP : @tab X
"X" means that the feature in that column (encoding / decoding) is supported.
Image Formats
FFmpeg can read and write images for each frame of a video sequence. The following image
formats are supported:
Name : Encoding @tab Decoding @tab Comments
.Y.U.V : X @tab X
@tab one raw file per component
Alias PIX : X @tab X
@tab Alias/Wavefront PIX image format
animated GIF : X @tab X
APNG : X @tab X
@tab Animated Portable Network Graphics
BMP : X @tab X
@tab Microsoft BMP image
BRender PIX : @tab X
@tab Argonaut BRender 3D engine image format.
CRI : @tab X
@tab Cintel RAW
DPX : X @tab X
@tab Digital Picture Exchange
EXR : @tab X
@tab OpenEXR
FITS : X @tab X
@tab Flexible Image Transport System
HDR : X @tab X
@tab Radiance HDR RGBE Image format
IMG : @tab X
@tab GEM Raster image
JPEG : X @tab X
@tab Progressive JPEG is not supported.
JPEG 2000 : X @tab X
JPEG-LS : X @tab X
LJPEG : X @tab
@tab Lossless JPEG
Media 100 : @tab X
MSP : @tab X
@tab Microsoft Paint image
PAM : X @tab X
@tab PAM is a PNM extension with alpha support.
PBM : X @tab X
@tab Portable BitMap image
PCD : @tab X
@tab PhotoCD
PCX : X @tab X
@tab PC Paintbrush
PFM : X @tab X
@tab Portable FloatMap image
PGM : X @tab X
@tab Portable GrayMap image
PGMYUV : X @tab X
@tab PGM with U and V components in YUV 4:2:0
PGX : @tab X
@tab PGX file decoder
PHM : X @tab X
@tab Portable HalfFloatMap image
PIC : @tab X
@tab Pictor/PC Paint
PNG : X @tab X
@tab Portable Network Graphics image
PPM : X @tab X
@tab Portable PixelMap image
PSD : @tab X
@tab Photoshop
PTX : @tab X
@tab V.Flash PTX format
QOI : X @tab X
@tab Quite OK Image format
SGI : X @tab X
@tab SGI RGB image format
Sun Rasterfile : X @tab X
@tab Sun RAS image format
TIFF : X @tab X
@tab YUV, JPEG and some extension is not supported yet.
Truevision Targa : X @tab X
@tab Targa (.TGA) image format
VBN : X @tab X
@tab Vizrt Binary Image format
WBMP : X @tab X
@tab Wireless Application Protocol Bitmap image format
WebP : E @tab X
@tab WebP image format, encoding supported through external library libwebp
XBM : X @tab X
@tab X BitMap image format
XFace : X @tab X
@tab X-Face image format
XPM : @tab X
@tab X PixMap image format
XWD : X @tab X
@tab X Window Dump image format
"X" means that the feature in that column (encoding / decoding) is supported.
"E" means that support is provided through an external library.
Video Codecs
Name : Encoding @tab Decoding @tab Comments
4X Movie : @tab X
@tab Used in certain computer games.
8088flex TMV : @tab X
A64 multicolor : X @tab
@tab Creates video suitable to be played on a commodore 64 (multicolor mode).
Amazing Studio PAF Video : @tab X
American Laser Games MM : @tab X
@tab Used in games like Mad Dog McCree.
Amuse Graphics Movie : @tab X
AMV Video : X @tab X
@tab Used in Chinese MP3 players.
ANSI/ASCII art : @tab X
Apple Intermediate Codec : @tab X
Apple MJPEG-B : @tab X
Apple Pixlet : @tab X
Apple ProRes : X @tab X
@tab fourcc: apch,apcn,apcs,apco,ap4h,ap4x
Apple QuickDraw : @tab X
@tab fourcc: qdrw
Argonaut Video : @tab X
@tab Used in some Argonaut games.
Asus v1 : X @tab X
@tab fourcc: ASV1
Asus v2 : X @tab X
@tab fourcc: ASV2
ATI VCR1 : @tab X
@tab fourcc: VCR1
ATI VCR2 : @tab X
@tab fourcc: VCR2
Auravision Aura : @tab X
Auravision Aura 2 : @tab X
Autodesk Animator Flic video : @tab X
Autodesk RLE : @tab X
@tab fourcc: AASC
AV1 : E @tab E
@tab Supported through external libraries libaom, libdav1d, librav1e and libsvtav1
Avid 1:1 10-bit RGB Packer : X @tab X
@tab fourcc: AVrp
AVS (Audio Video Standard) video : @tab X
@tab Video encoding used by the Creature Shock game.
AVS2-P2/IEEE1857.4 : E @tab E
@tab Supported through external libraries libxavs2 and libdavs2
AVS3-P2/IEEE1857.10 : @tab E
@tab Supported through external library libuavs3d
AYUV : X @tab X
@tab Microsoft uncompressed packed 4:4:4:4
Beam Software VB : @tab X
Bethesda VID video : @tab X
@tab Used in some games from Bethesda Softworks.
Bink Video : @tab X
BitJazz SheerVideo : @tab X
Bitmap Brothers JV video : @tab X
y41p Brooktree uncompressed 4:1:1 12-bit : X @tab X
Brooktree ProSumer Video : @tab X
@tab fourcc: BT20
Brute Force & Ignorance : @tab X
@tab Used in the game Flash Traffic: City of Angels.
C93 video : @tab X
@tab Codec used in Cyberia game.
CamStudio : @tab X
@tab fourcc: CSCD
CD+G : @tab X
@tab Video codec for CD+G karaoke disks
CDXL : @tab X
@tab Amiga CD video codec
Chinese AVS video : E @tab X
@tab AVS1-P2, JiZhun profile, encoding through external library libxavs
Delphine Software International CIN video : @tab X
@tab Codec used in Delphine Software International games.
Discworld II BMV Video : @tab X
CineForm HD : X @tab X
Canopus HQ : @tab X
Canopus HQA : @tab X
Canopus HQX : @tab X
Canopus Lossless Codec : @tab X
CDToons : @tab X
@tab Codec used in various Broderbund games.
Cinepak : @tab X
Cirrus Logic AccuPak : X @tab X
@tab fourcc: CLJR
CPiA Video Format : @tab X
Creative YUV (CYUV) : @tab X
DFA : @tab X
@tab Codec used in Chronomaster game.
Dirac : E @tab X
@tab supported though the native vc2 (Dirac Pro) encoder
Deluxe Paint Animation : @tab X
DNxHD : X @tab X
@tab aka SMPTE VC3
Duck TrueMotion 1.0 : @tab X
@tab fourcc: DUCK
Duck TrueMotion 2.0 : @tab X
@tab fourcc: TM20
Duck TrueMotion 2.0 RT : @tab X
@tab fourcc: TR20
DV (Digital Video) : X @tab X
Dxtory capture format : @tab X
Feeble Files/ScummVM DXA : @tab X
@tab Codec originally used in Feeble Files game.
Electronic Arts CMV video : @tab X
@tab Used in NHL 95 game.
Electronic Arts Madcow video : @tab X
Electronic Arts TGV video : @tab X
Electronic Arts TGQ video : @tab X
Electronic Arts TQI video : @tab X
Escape 124 : @tab X
Escape 130 : @tab X
EVC / MPEG-5 Part 1 : E @tab E
@tab encoding and decoding supported through external libraries libxeve and libxevd
FFmpeg video codec #1 : X @tab X
@tab lossless codec (fourcc: FFV1)
Flash Screen Video v1 : X @tab X
@tab fourcc: FSV1
Flash Screen Video v2 : X @tab X
Flash Video (FLV) : X @tab X
@tab Sorenson H.263 used in Flash
FM Screen Capture Codec : @tab X
Forward Uncompressed : @tab X
Fraps : @tab X
Go2Meeting : @tab X
@tab fourcc: G2M2, G2M3
Go2Webinar : @tab X
@tab fourcc: G2M4
Gremlin Digital Video : @tab X
H.261 : X @tab X
H.263 / H.263-1996 : X @tab X
H.263+ / H.263-1998 / H.263 version 2 : X @tab X
H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10 : E @tab X
@tab encoding supported through external library libx264 and OpenH264
HEVC : X @tab X
@tab encoding supported through external library libx265 and libkvazaar
HNM version 4 : @tab X
HuffYUV : X @tab X
HuffYUV FFmpeg variant : X @tab X
IBM Ultimotion : @tab X
@tab fourcc: ULTI
id Cinematic video : @tab X
@tab Used in Quake II.
id RoQ video : X @tab X
@tab Used in Quake III, Jedi Knight 2, other computer games.
IFF ILBM : @tab X
@tab IFF interleaved bitmap
IFF ByteRun1 : @tab X
@tab IFF run length encoded bitmap
Infinity IMM4 : @tab X
Intel H.263 : @tab X
Intel Indeo 2 : @tab X
Intel Indeo 3 : @tab X
Intel Indeo 4 : @tab X
Intel Indeo 5 : @tab X
Interplay C93 : @tab X
@tab Used in the game Cyberia from Interplay.
Interplay MVE video : @tab X
@tab Used in Interplay .MVE files.
J2K : X @tab X
Karl Morton's video codec : @tab X
@tab Codec used in Worms games.
Kega Game Video (KGV1) : @tab X
@tab Kega emulator screen capture codec.
Lagarith : @tab X
LCEVC / MPEG-5 LCEVC / MPEG-5 Part 2 : @tab E
@tab decoding supported through external library liblcevc-dec
LCL (LossLess Codec Library) MSZH : @tab X
LCL (LossLess Codec Library) ZLIB : E @tab E
LEAD MCMP : @tab X
LOCO : @tab X
LucasArts SANM/Smush : @tab X
@tab Used in LucasArts games / SMUSH animations.
lossless MJPEG : X @tab X
MagicYUV Video : X @tab X
Mandsoft Screen Capture Codec : @tab X
Microsoft ATC Screen : @tab X
@tab Also known as Microsoft Screen 3.
Microsoft Expression Encoder Screen : @tab X
@tab Also known as Microsoft Titanium Screen 2.
Microsoft RLE : X @tab X
Microsoft Screen 1 : @tab X
@tab Also known as Windows Media Video V7 Screen.
Microsoft Screen 2 : @tab X
@tab Also known as Windows Media Video V9 Screen.
Microsoft Video 1 : @tab X
Mimic : @tab X
@tab Used in MSN Messenger Webcam streams.
Miro VideoXL : @tab X
@tab fourcc: VIXL
MJPEG (Motion JPEG) : X @tab X
Mobotix MxPEG video : @tab X
Motion Pixels video : @tab X
MPEG-1 video : X @tab X
MPEG-2 video : X @tab X
MPEG-4 part 2 : X @tab X
@tab libxvidcore can be used alternatively for encoding.
MPEG-4 part 2 Microsoft variant version 1 : @tab X
MPEG-4 part 2 Microsoft variant version 2 : X @tab X
MPEG-4 part 2 Microsoft variant version 3 : X @tab X
Newtek SpeedHQ : X @tab X
Nintendo Gamecube THP video : @tab X
NotchLC : @tab X
NuppelVideo/RTjpeg : @tab X
@tab Video encoding used in NuppelVideo files.
On2 VP3 : @tab X
@tab still experimental
On2 VP4 : @tab X
@tab fourcc: VP40
On2 VP5 : @tab X
@tab fourcc: VP50
On2 VP6 : @tab X
@tab fourcc: VP60,VP61,VP62
On2 VP7 : @tab X
@tab fourcc: VP70,VP71
VP8 : E @tab X
@tab fourcc: VP80, encoding supported through external library libvpx
VP9 : E @tab X
@tab encoding supported through external library libvpx
Pinnacle TARGA CineWave YUV16 : @tab X
@tab fourcc: Y216
Q-team QPEG : @tab X
@tab fourccs: QPEG, Q1.0, Q1.1
QuickTime 8BPS video : @tab X
QuickTime Animation (RLE) video : X @tab X
@tab fourcc: 'rle '
QuickTime Graphics (SMC) : X @tab X
@tab fourcc: 'smc '
QuickTime video (RPZA) : X @tab X
@tab fourcc: rpza
R10K AJA Kona 10-bit RGB Codec : X @tab X
R210 Quicktime Uncompressed RGB 10-bit : X @tab X
Raw Video : X @tab X
RealVideo 1.0 : X @tab X
RealVideo 2.0 : X @tab X
RealVideo 3.0 : @tab X
@tab still far from ideal
RealVideo 4.0 : @tab X
Renderware TXD (TeXture Dictionary) : @tab X
@tab Texture dictionaries used by the Renderware Engine.
RivaTuner Video : @tab X
@tab fourcc: 'RTV1'
RL2 video : @tab X
@tab used in some games by Entertainment Software Partners
ScreenPressor : @tab X
Screenpresso : @tab X
Screen Recorder Gold Codec : @tab X
Sierra VMD video : @tab X
@tab Used in Sierra VMD files.
Silicon Graphics Motion Video Compressor 1 (MVC1) : @tab X
Silicon Graphics Motion Video Compressor 2 (MVC2) : @tab X
Silicon Graphics RLE 8-bit video : @tab X
Smacker video : @tab X
@tab Video encoding used in Smacker.
SMPTE VC-1 : @tab X
Snow : X @tab X
@tab experimental wavelet codec (fourcc: SNOW)
Sony PlayStation MDEC (Motion DECoder) : @tab X
Sorenson Vector Quantizer 1 : X @tab X
@tab fourcc: SVQ1
Sorenson Vector Quantizer 3 : @tab X
@tab fourcc: SVQ3
Sunplus JPEG (SP5X) : @tab X
@tab fourcc: SP5X
TechSmith Screen Capture Codec : @tab X
@tab fourcc: TSCC
TechSmith Screen Capture Codec 2 : @tab X
@tab fourcc: TSC2
Theora : E @tab X
@tab encoding supported through external library libtheora
Tiertex Limited SEQ video : @tab X
@tab Codec used in DOS CD-ROM FlashBack game.
Ut Video : X @tab X
v210 QuickTime uncompressed 4:2:2 10-bit : X @tab X
v308 QuickTime uncompressed 4:4:4 : X @tab X
v408 QuickTime uncompressed 4:4:4:4 : X @tab X
v410 QuickTime uncompressed 4:4:4 10-bit : X @tab X
VBLE Lossless Codec : @tab X
vMix Video : @tab X
@tab fourcc: 'VMX1'
VMware Screen Codec / VMware Video : @tab X
@tab Codec used in videos captured by VMware.
Westwood Studios VQA (Vector Quantized Animation) video : @tab X
Windows Media Image : @tab X
Windows Media Video 7 : X @tab X
Windows Media Video 8 : X @tab X
Windows Media Video 9 : @tab X
@tab not completely working
Wing Commander III / Xan : @tab X
@tab Used in Wing Commander III .MVE files.
Wing Commander IV / Xan : @tab X
@tab Used in Wing Commander IV.
Winnov WNV1 : @tab X
WMV7 : X @tab X
YAMAHA SMAF : X @tab X
Psygnosis YOP Video : @tab X
yuv4 : X @tab X
@tab libquicktime uncompressed packed 4:2:0
ZeroCodec Lossless Video : @tab X
ZLIB : X @tab X
@tab part of LCL, encoder experimental
Zip Motion Blocks Video : X @tab X
@tab Encoder works only in PAL8.
"X" means that the feature in that column (encoding / decoding) is supported.
"E" means that support is provided through an external library.
Audio Codecs
Name : Encoding @tab Decoding @tab Comments
8SVX exponential : @tab X
8SVX fibonacci : @tab X
AAC : EX @tab X
@tab encoding supported through internal encoder and external library libfdk-aac
AAC+ : E @tab IX
@tab encoding supported through external library libfdk-aac
AC-3 : IX @tab IX
ACELP.KELVIN : @tab X
ADPCM 4X Movie : @tab X
ADPCM Yamaha AICA : @tab X
ADPCM AmuseGraphics Movie : @tab X
ADPCM Argonaut Games : X @tab X
ADPCM CDROM XA : @tab X
ADPCM Creative Technology : @tab X
@tab 16 -E<gt> 4, 8 -E<gt> 4, 8 -E<gt> 3, 8 -E<gt> 2
ADPCM Electronic Arts : @tab X
@tab Used in various EA titles.
ADPCM Electronic Arts Maxis CDROM XS : @tab X
@tab Used in Sim City 3000.
ADPCM Electronic Arts R1 : @tab X
ADPCM Electronic Arts R2 : @tab X
ADPCM Electronic Arts R3 : @tab X
ADPCM Electronic Arts XAS : @tab X
ADPCM G.722 : X @tab X
ADPCM G.726 : X @tab X
ADPCM IMA Acorn Replay : @tab X
ADPCM IMA AMV : X @tab X
@tab Used in AMV files
ADPCM IMA Cunning Developments : @tab X
ADPCM IMA Electronic Arts EACS : @tab X
ADPCM IMA Electronic Arts SEAD : @tab X
ADPCM IMA Funcom : @tab X
ADPCM IMA High Voltage Software ALP : X @tab X
ADPCM IMA Mobiclip MOFLEX : @tab X
ADPCM IMA QuickTime : X @tab X
ADPCM IMA Simon & Schuster Interactive : X @tab X
ADPCM IMA Ubisoft APM : X @tab X
ADPCM IMA Loki SDL MJPEG : @tab X
ADPCM IMA WAV : X @tab X
ADPCM IMA Westwood : @tab X
ADPCM ISS IMA : @tab X
@tab Used in FunCom games.
ADPCM IMA Dialogic : @tab X
ADPCM IMA Duck DK3 : @tab X
@tab Used in some Sega Saturn console games.
ADPCM IMA Duck DK4 : @tab X
@tab Used in some Sega Saturn console games.
ADPCM IMA Radical : @tab X
ADPCM Microsoft : X @tab X
ADPCM MS IMA : X @tab X
ADPCM Nintendo Gamecube AFC : @tab X
ADPCM Nintendo Gamecube DTK : @tab X
ADPCM Nintendo THP : @tab X
ADPCM Playstation : @tab X
ADPCM QT IMA : X @tab X
ADPCM SEGA CRI ADX : X @tab X
@tab Used in Sega Dreamcast games.
ADPCM Shockwave Flash : X @tab X
ADPCM Sound Blaster Pro 2-bit : @tab X
ADPCM Sound Blaster Pro 2.6-bit : @tab X
ADPCM Sound Blaster Pro 4-bit : @tab X
ADPCM VIMA : @tab X
@tab Used in LucasArts SMUSH animations.
ADPCM Konami XMD : @tab X
ADPCM Westwood Studios IMA : X @tab X
@tab Used in Westwood Studios games like Command and Conquer.
ADPCM Yamaha : X @tab X
ADPCM Zork : @tab X
AMR-NB : E @tab X
@tab encoding supported through external library libopencore-amrnb
AMR-WB : E @tab X
@tab encoding supported through external library libvo-amrwbenc
Amazing Studio PAF Audio : @tab X
Apple lossless audio : X @tab X
@tab QuickTime fourcc 'alac'
aptX : X @tab X
@tab Used in Bluetooth A2DP
aptX HD : X @tab X
@tab Used in Bluetooth A2DP
ATRAC1 : @tab X
ATRAC3 : @tab X
ATRAC3+ : @tab X
ATRAC9 : @tab X
Bink Audio : @tab X
@tab Used in Bink and Smacker files in many games.
Bonk audio : @tab X
CELT : @tab E
@tab decoding supported through external library libcelt
codec2 : E @tab E
@tab en/decoding supported through external library libcodec2
CRI HCA : @tab X
Delphine Software International CIN audio : @tab X
@tab Codec used in Delphine Software International games.
DFPWM : X @tab X
Digital Speech Standard - Standard Play mode (DSS SP) : @tab X
Discworld II BMV Audio : @tab X
COOK : @tab X
@tab All versions except 5.1 are supported.
DCA (DTS Coherent Acoustics) : X @tab X
@tab supported extensions: XCh, XXCH, X96, XBR, XLL, LBR (partially)
Dolby E : @tab X
DPCM Cuberoot-Delta-Exact : @tab X
@tab Used in few games.
DPCM Gremlin : @tab X
DPCM id RoQ : X @tab X
@tab Used in Quake III, Jedi Knight 2 and other computer games.
DPCM Marble WADY : @tab X
DPCM Interplay : @tab X
@tab Used in various Interplay computer games.
DPCM Squareroot-Delta-Exact : @tab X
@tab Used in various games.
DPCM Sierra Online : @tab X
@tab Used in Sierra Online game audio files.
DPCM Sol : @tab X
DPCM Xan : @tab X
@tab Used in Origin's Wing Commander IV AVI files.
DPCM Xilam DERF : @tab X
DSD (Direct Stream Digital), least significant bit first : @tab X
DSD (Direct Stream Digital), most significant bit first : @tab X
DSD (Direct Stream Digital), least significant bit first, planar : @tab X
DSD (Direct Stream Digital), most significant bit first, planar : @tab X
DSP Group TrueSpeech : @tab X
DST (Direct Stream Transfer) : @tab X
DV audio : @tab X
Enhanced AC-3 : X @tab X
EVRC (Enhanced Variable Rate Codec) : @tab X
FLAC (Free Lossless Audio Codec) : X @tab IX
FTR Voice : @tab X
G.723.1 : X @tab X
G.729 : @tab X
GSM : E @tab X
@tab encoding supported through external library libgsm
GSM Microsoft variant : E @tab X
@tab encoding supported through external library libgsm
IAC (Indeo Audio Coder) : @tab X
iLBC (Internet Low Bitrate Codec) : E @tab EX
@tab encoding and decoding supported through external library libilbc
IMC (Intel Music Coder) : @tab X
Interplay ACM : @tab X
LC3 : E @tab E
@tab supported through external library liblc3
MACE (Macintosh Audio Compression/Expansion) 6:1 : @tab X
Marian's A-pac audio : @tab X
MI-SC4 (Micronas SC-4 Audio) : @tab X
MLP (Meridian Lossless Packing) : X @tab X
@tab Used in DVD-Audio discs.
Monkey's Audio : @tab X
MP1 (MPEG audio layer 1) : @tab IX
MP2 (MPEG audio layer 2) : IX @tab IX
@tab encoding supported also through external library TwoLAME
MP3 (MPEG audio layer 3) : E @tab IX
@tab encoding supported through external library LAME, ADU MP3 and MP3onMP4 also supported
MPEG-4 Audio Lossless Coding (ALS) : @tab X
MobiClip FastAudio : @tab X
Musepack SV7 : @tab X
Musepack SV8 : @tab X
Nellymoser Asao : X @tab X
On2 AVC (Audio for Video Codec) : @tab X
Opus : E @tab X
@tab encoding supported through external library libopus
OSQ (Original Sound Quality) : @tab X
PCM A-law : X @tab X
PCM mu-law : X @tab X
PCM Archimedes VIDC : X @tab X
PCM signed 8-bit planar : X @tab X
PCM signed 16-bit big-endian planar : X @tab X
PCM signed 16-bit little-endian planar : X @tab X
PCM signed 24-bit little-endian planar : X @tab X
PCM signed 32-bit little-endian planar : X @tab X
PCM 32-bit floating point big-endian : X @tab X
PCM 32-bit floating point little-endian : X @tab X
PCM 64-bit floating point big-endian : X @tab X
PCM 64-bit floating point little-endian : X @tab X
PCM D-Cinema audio signed 24-bit : X @tab X
PCM signed 8-bit : X @tab X
PCM signed 16-bit big-endian : X @tab X
PCM signed 16-bit little-endian : X @tab X
PCM signed 24-bit big-endian : X @tab X
PCM signed 24-bit little-endian : X @tab X
PCM signed 32-bit big-endian : X @tab X
PCM signed 32-bit little-endian : X @tab X
PCM signed 16/20/24-bit big-endian in MPEG-TS : @tab X
PCM unsigned 8-bit : X @tab X
PCM unsigned 16-bit big-endian : X @tab X
PCM unsigned 16-bit little-endian : X @tab X
PCM unsigned 24-bit big-endian : X @tab X
PCM unsigned 24-bit little-endian : X @tab X
PCM unsigned 32-bit big-endian : X @tab X
PCM unsigned 32-bit little-endian : X @tab X
PCM SGA : @tab X
QCELP / PureVoice : @tab X
QDesign Music Codec 1 : @tab X
QDesign Music Codec 2 : @tab X
@tab There are still some distortions.
RealAudio 1.0 (14.4K) : X @tab X
@tab Real 14400 bit/s codec
RealAudio 2.0 (28.8K) : @tab X
@tab Real 28800 bit/s codec
RealAudio 3.0 (dnet) : IX @tab X
@tab Real low bitrate AC-3 codec
RealAudio Lossless : @tab X
RealAudio SIPR / ACELP.NET : @tab X
RK Audio (RKA) : @tab X
SBC (low-complexity subband codec) : X @tab X
@tab Used in Bluetooth A2DP
Shorten : @tab X
Sierra VMD audio : @tab X
@tab Used in Sierra VMD files.
Smacker audio : @tab X
SMPTE 302M AES3 audio : X @tab X
Sonic : X @tab X
@tab experimental codec
Sonic lossless : X @tab X
@tab experimental codec
Speex : E @tab EX
@tab supported through external library libspeex
TAK (Tom's lossless Audio Kompressor) : @tab X
True Audio (TTA) : X @tab X
TrueHD : X @tab X
@tab Used in HD-DVD and Blu-Ray discs.
TwinVQ (VQF flavor) : @tab X
VIMA : @tab X
@tab Used in LucasArts SMUSH animations.
ViewQuest VQC : @tab X
Vorbis : E @tab X
@tab A native but very primitive encoder exists.
Voxware MetaSound : @tab X
Waveform Archiver : @tab X
WavPack : X @tab X
Westwood Audio (SND1) : @tab X
Windows Media Audio 1 : X @tab X
Windows Media Audio 2 : X @tab X
Windows Media Audio Lossless : @tab X
Windows Media Audio Pro : @tab X
Windows Media Audio Voice : @tab X
Xbox Media Audio 1 : @tab X
Xbox Media Audio 2 : @tab X
"X" means that the feature in that column (encoding / decoding) is supported.
"E" means that support is provided through an external library.
"I" means that an integer-only version is available, too (ensures high performance on
systems without hardware floating point support).
Subtitle Formats
Name : Muxing @tab Demuxing @tab Encoding @tab Decoding
3GPP Timed Text : @tab @tab X @tab X
AQTitle : @tab X @tab @tab X
DVB : X @tab X @tab X @tab X
DVB teletext : @tab X @tab @tab E
DVD : X @tab X @tab X @tab X
JACOsub : X @tab X @tab @tab X
MicroDVD : X @tab X @tab @tab X
MPL2 : @tab X @tab @tab X
MPsub (MPlayer) : @tab X @tab @tab X
PGS : @tab @tab @tab X
PJS (Phoenix) : @tab X @tab @tab X
RealText : @tab X @tab @tab X
SAMI : @tab X @tab @tab X
Spruce format (STL) : @tab X @tab @tab X
SSA/ASS : X @tab X @tab X @tab X
SubRip (SRT) : X @tab X @tab X @tab X
SubViewer v1 : @tab X @tab @tab X
SubViewer : @tab X @tab @tab X
TED Talks captions : @tab X @tab @tab X
TTML : X @tab @tab X @tab
VobSub (IDX+SUB) : @tab X @tab @tab X
VPlayer : @tab X @tab @tab X
WebVTT : X @tab X @tab X @tab X
XSUB : @tab @tab X @tab X
"X" means that the feature is supported.
"E" means that support is provided through an external library.
Network Protocols
Name : Support
AMQP : E
file : X
FTP : X
Gopher : X
Gophers : X
HLS : X
HTTP : X
HTTPS : X
Icecast : X
MMSH : X
MMST : X
pipe : X
Pro-MPEG FEC : X
RTMP : X
RTMPE : X
RTMPS : X
RTMPT : X
RTMPTE : X
RTMPTS : X
RTP : X
SAMBA : E
SCTP : X
SFTP : E
TCP : X
TLS : X
UDP : X
ZMQ : E
"X" means that the protocol is supported.
"E" means that support is provided through an external library.
Input/Output Devices
Name : Input @tab Output
ALSA : X @tab X
BKTR : X @tab
caca : @tab X
DV1394 : X @tab
Lavfi virtual device : X @tab
Linux framebuffer : X @tab X
JACK : X @tab
LIBCDIO : X
LIBDC1394 : X @tab
OpenAL : X
OpenGL : @tab X
OSS : X @tab X
PulseAudio : X @tab X
SDL : @tab X
Video4Linux2 : X @tab X
VfW capture : X @tab
X11 grabbing : X @tab
Win32 grabbing : X @tab
"X" means that input/output is supported.
Timecode
Codec/format : Read @tab Write
AVI : X @tab X
DV : X @tab X
GXF : X @tab X
MOV : X @tab X
MPEG1/2 : X @tab X
MXF : X @tab X
SEE ALSO
ffprobe(1), ffmpeg(1), ffplay(1), ffmpeg-utils(1), ffmpeg-scaler(1), ffmpeg-resampler(1),
ffmpeg-codecs(1), ffmpeg-bitstream-filters(1), ffmpeg-formats(1), ffmpeg-devices(1),
ffmpeg-protocols(1), ffmpeg-filters(1)
AUTHORS
The FFmpeg developers.
For details about the authorship, see the Git history of the project
(https://git.ffmpeg.org/ffmpeg), e.g. by typing the command git log in the FFmpeg source
directory, or browsing the online repository at <https://git.ffmpeg.org/ffmpeg>.
Maintainers for the specific components are listed in the file MAINTAINERS in the source
code tree.
FFPROBE-ALL(1)