Provided by: ffmpeg_4.1.3-1_amd64 bug

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.

       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
       print_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" 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.

   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.

       stream_type[:stream_index]
           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 stream_index is given, then it matches stream number stream_index of this
           type. Otherwise, it matches all streams of this type.

       p:program_id[:stream_index] or p:program_id[:stream_type[:stream_index]] or
           p:program_id:m:key[:value] In first version, if stream_index is given, then it matches
           the stream with number stream_index in the program with the id program_id. Otherwise,
           it matches all streams in the program. In the second version, stream_type is one of
           following: 'v' for video, 'a' for audio, 's' for subtitle, 'd' for data. If
           stream_index is also given, then it matches stream number stream_index of this type in
           the program with the id program_id.  Otherwise, if only stream_type is given, it
           matches all streams of this type in the program with the id program_id.  In the third
           version matches streams in the program with the id program_id with the metadata tag
           key having the specified value. If value is not given, matches streams that contain
           the given tag with any value.

       #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.

       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 name filter_name. Use the -filters
               option to get a list of all filters.

       -version
           Show version.

       -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.

       -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 NO_COLOR, or can be forced setting the
           environment variable AV_LOG_FORCE_COLOR.  The use of the environment variable NO_COLOR
           is deprecated and will be dropped in a future FFmpeg version.

       -report
           Dump full command line and console 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 verbose".

           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

   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.

       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".

       -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:

                   -print_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_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".

       -bitexact
           Force bitexact output, useful to produce output which is not dependent on the specific
           build.

       -i input_url
           Read input_url.

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 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 specifid, 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 <http://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 expresses the number of seconds, with the optional decimal part m.

       In both expressions, the optional - indicates negative duration.

       Examples

       The following examples are all valid time duration:

       55  55 seconds

       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

       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

       octagonal
           FL+FR+FC+BL+BR+BC+SL+SR

       downmix
           DL+DR

       A custom channel layout can be specified as a sequence of terms, separated by '+' or '|'.
       Each term can be:

       ·   the name of a standard channel layout (e.g. mono, stereo, 4.0, quad, 5.0, etc.)

       ·   the name of a single channel (e.g. FL, FR, FC, LFE, etc.)

       ·   a number of channels, in decimal, followed by 'c', yielding the default channel layout
           for that number of channels (see the function "av_get_default_channel_layout"). 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_get_channel_layout" 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: "+", "-".

       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(x, y)
           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(var)
           Load the value of the internal variable with number var, which was previously stored
           with st(var, 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.  Returns the value of the expression printed.

           Prints t with loglevel l

       random(x)
           Return a pseudo random value between 0.0 and 1.0. x is the index of the internal
           variable which will be used to save the seed/state.

       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".

       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(var, expr)
           Store the value of the expression expr in an internal variable. var specifies the
           number 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.  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, id)
           Evaluate a Taylor series at x, given an expression representing the "ld(id)"-th
           derivative of a function at 0.

           When the series does not converge the result is undefined.

           ld(id) 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(id)". If id 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 / 2^40

       E   10^18 / 2^50

       Z   10^21 / 2^60

       Y   10^24 / 2^70

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.

           emu_edge
               Do not draw edges.

           psnr
               Set error[?] variables during encoding.

           truncated
           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.

           cbp Deprecated, use mpegvideo private options instead.

           qprd
               Deprecated, use mpegvideo private options instead.

           ilme
               Apply interlaced motion estimation.

           cgop
               Use closed gop.

       me_method integer (encoding,video)
           Set motion estimation method.

           Possible values:

           zero
               zero motion estimation (fastest)

           full
               full motion estimation (slowest)

           epzs
               EPZS motion estimation (default)

           esa esa motion estimation (alias for full)

           tesa
               tesa motion estimation

           dia dia motion estimation (alias for epzs)

           log log motion estimation

           phods
               phods motion estimation

           x1  X1 motion estimation

           hex hex motion estimation

           umh umh motion estimation

           iter
               iter motion estimation

       extradata_size integer
           Set extradata size.

       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.

       rc_strategy integer (encoding,video)
           Set ratecontrol method.

       b_strategy integer (encoding,video)
           Set strategy to choose between I/P/B-frames.

       ps integer (encoding,video)
           Set RTP payload size in bytes.

       mv_bits integer
       header_bits integer
       i_tex_bits integer
       p_tex_bits integer
       i_count integer
       p_count integer
       skip_count integer
       misc_bits integer
       frame_bits integer
       codec_tag integer
       bug flags (decoding,video)
           Workaround not auto detected encoder bugs.

           Possible values:

           autodetect
           old_msmpeg4
               some old lavc generated msmpeg4v3 files (no autodetection)

           xvid_ilace
               Xvid interlacing bug (autodetected if fourcc==XVIX)

           ump4
               (autodetected if fourcc==UMP4)

           no_padding
               padding bug (autodetected)

           amv
           ac_vlc
               illegal vlc bug (autodetected per fourcc)

           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

       lelim integer (encoding,video)
           Set single coefficient elimination threshold for luminance (negative values also
           consider DC coefficient).

       celim integer (encoding,video)
           Set single coefficient elimination threshold for chrominance (negative values also
           consider dc coefficient)

       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
       mpeg_quant integer (encoding,video)
           Use MPEG quantizers instead of H.263.

       qsquish float (encoding,video)
           How to keep quantizer between qmin and qmax (0 = clip, 1 = use differentiable
           function).

       rc_qmod_amp float (encoding,video)
           Set experimental quantizer modulation.

       rc_qmod_freq integer (encoding,video)
           Set experimental quantizer modulation.

       rc_override_count integer
       rc_eq string (encoding,video)
           Set rate control equation. When computing the expression, besides the standard
           functions defined in the section 'Expression Evaluation', the following functions are
           available: bits2qp(bits), qp2bits(qp). Also the following constants are available:
           iTex pTex tex mv fCode iCount mcVar var isI isP isB avgQP qComp avgIITex avgPITex
           avgPPTex avgBPTex avgTex.

       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).

       rc_buf_aggressivity float (encoding,video)
           Currently useless.

       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.

       rc_init_cplx float (encoding,video)
           Set initial complexity for 1-pass encoding.

       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
           simplealpha
           ipp
           xvidmmx
           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
       pred integer (encoding,video)
           Set prediction method.

           Possible values:

           left
           plane
           median
       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.

       last_pred integer (encoding,video)
           Set amount of motion predictors from the previous frame.

       preme integer (encoding,video)
           Set pre motion estimation.

       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.

       dtg_active_format integer
       me_range integer (encoding,video)
           Set limit motion vectors range (1023 for DivX player).

       ibias integer (encoding,video)
           Set intra quant bias.

       pbias integer (encoding,video)
           Set inter quant bias.

       color_table_id integer
       global_quality integer (encoding,audio,video)
       coder integer (encoding,video)
           Possible values:

           vlc variable length coder / huffman coder

           ac  arithmetic coder

           raw raw (no encoding)

           rle run-length coder

           deflate
               deflate-based coder

       context integer (encoding,video)
           Set context model.

       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

       stream_codec_tag integer
       sc_threshold integer (encoding,video)
           Set scene change threshold.

       lmin integer (encoding,video)
           Set min lagrange factor (VBR).

       lmax integer (encoding,video)
           Set max lagrange factor (VBR).

       nr integer (encoding,video)
           Set noise reduction.

       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)
           Possible values:

           fast
               Allow non spec compliant speedup tricks.

           sgop
               Deprecated, use mpegvideo private options instead.

           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.

           skiprd
               Deprecated, use mpegvideo private options instead.

           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.

       error integer (encoding,video)
       qns integer (encoding,video)
           Deprecated, use mpegvideo private options instead.

       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.

       me_threshold integer (encoding,video)
           Set motion estimation threshold.

       mb_threshold integer (encoding,video)
           Set macroblock threshold.

       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)
           Possible values:

           unknown
           aac_main
           aac_low
           aac_ssr
           aac_ltp
           aac_he
           aac_he_v2
           aac_ld
           aac_eld
           mpeg2_aac_low
           mpeg2_aac_he
           mpeg4_sp
           mpeg4_core
           mpeg4_main
           mpeg4_asp
           dts
           dts_es
           dts_96_24
           dts_hd_hra
           dts_hd_ma
       level integer (encoding,audio,video)
           Possible values:

           unknown
       lowres integer (decoding,audio,video)
           Decode at 1= 1/2, 2=1/4, 3=1/8 resolutions.

       skip_threshold integer (encoding,video)
           Set frame skip threshold.

       skip_factor integer (encoding,video)
           Set frame skip factor.

       skip_exp integer (encoding,video)
           Set frame skip exponent.  Negative values behave identical to the corresponding
           positive ones, except that the score is normalized.  Positive values exist primarily
           for compatibility reasons and are not so useful.

       skipcmp integer (encoding,video)
           Set frame skip 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
       border_mask float (encoding,video)
           Increase the quantizer for macroblocks close to borders.

       mblmin integer (encoding,video)
           Set min macroblock lagrange factor (VBR).

       mblmax integer (encoding,video)
           Set max macroblock lagrange factor (VBR).

       mepc integer (encoding,video)
           Set motion estimation bitrate penalty compensation (1.0 = 256).

       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.

           all Discard all frames.

           Default value is default.

       bidir_refine integer (encoding,video)
           Refine the two motion vectors used in bidirectional macroblocks.

       brd_scale integer (encoding,video)
           Downscale frames for dynamic B-frame decision.

       keyint_min integer (encoding,video)
           Set minimum interval between IDR-frames.

       refs integer (encoding,video)
           Set reference frames to consider for motion compensation.

       chromaoffset integer (encoding,video)
           Set chroma qp offset from luma.

       trellis integer (encoding,audio,video)
           Set rate-distortion optimal quantization.

       mv0_threshold integer (encoding,video)
       b_sensitivity integer (encoding,video)
           Adjust sensitivity of b_frame_strategy 1.

       compression_level integer (encoding,audio,video)
       min_prediction_order integer (encoding,audio)
       max_prediction_order integer (encoding,audio)
       timecode_frame_start integer (encoding,video)
           Set GOP timecode frame start number, in non drop frame format.

       request_channels integer (decoding,audio)
           Set desired number of audio channels.

       bits_per_raw_sample integer
       channel_layout integer (decoding/encoding,audio)
           Possible values:

       request_channel_layout integer (decoding,audio)
           Possible values:

       rc_max_vbv_use float (encoding,video)
       rc_min_vbv_use float (encoding,video)
       ticks_per_frame integer (decoding/encoding,audio,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

       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
               MPEG (219*2^(n-8))

           pc
           jpeg
               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 indention:

                   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.

   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

   libdavs2
       AVS2-P2/IEEE1857.4 video decoder wrapper.

       This decoder allows libavcodec to decode AVS2 streams with davs2 library.

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.  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

   dvbsub
       Options

       compute_clut
           -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 comas, 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_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 (num_units_in_display_tick / time_scale) 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.

   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.

   dump_extra
       Add extradata to the beginning of the filtered packets.

       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 e.

       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

   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.

       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

   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.

           insert
           remove
       sample_aspect_ratio
           Set the sample aspect ratio of the stream in the VUI parameters.

       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 (num_units_in_tick / time_scale) 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).

       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.

       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.

       A new single global PPS is created, and all of the redundant PPSs within the stream are
       removed.

   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 (num_units_in_tick / time_scale).
           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).

   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.

   mp3decomp
       Decompress non-standard compressed MP3 audio headers.

   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
           A numeral string, whose value is related to how often output bytes will be modified.
           Therefore, values below or equal to 0 are forbidden, and the lower the more frequent
           bytes will be modified, with 1 meaning every byte is modified.

       dropamount
           A numeral string, whose value is related to how often packets will be dropped.
           Therefore, values below or equal to 0 are forbidden, and the lower the more frequent
           packets will be dropped, with 1 meaning every packet is dropped.

       The following example applies the modification to every byte but does not drop any
       packets.

               ffmpeg -i INPUT -c copy -bsf noise[=1] output.mkv

   null
       This bitstream filter passes the packets through unchanged.

   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.

   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 H.264, H.265, MPEG-2 and VP9.

   vp9_metadata
       Modify metadata embedded in a VP9 stream.

       color_space
           Set the color space value in the frame header.

           unknown
           bt601
           bt709
           smpte170
           smpte240
           bt2020
           rgb
       color_range
           Set the color range value in the frame header.  Note that this cannot be set in RGB
           streams.

           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.

       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 set. Inert when nofillin is set.

           ignidx
               Ignore index.

           keepside (deprecated,inert)
           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.

           latm (deprecated,inert)
           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 1000000 (1 second).

           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 indention:

                   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 when calculated using PTS.  At present, applicable
           for MPEG-PS and MPEG-TS.

   Format stream specifiers
       Format stream specifiers allow selection of one or more streams that match specific
       properties.

       Possible forms of stream specifiers are:

       stream_index
           Matches the stream with this index.

       stream_type[:stream_index]
           stream_type is one of following: 'v' for video, 'a' for audio, 's' for subtitle, 'd'
           for data, and 't' for attachments. If stream_index is given, then it matches the
           stream number stream_index of this type. Otherwise, it matches all streams of this
           type.

       p:program_id[:stream_index]
           If stream_index is given, then it matches the stream with number stream_index in the
           program with the id program_id. Otherwise, it matches all streams in the program.

       #stream_id
           Matches the stream by a format-specific ID.

       The exact semantics of stream specifiers is defined by the
       "avformat_match_stream_specifier()" function declared in the libavformat/avformat.h
       header.

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.

   applehttp
       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".

   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.

       -max_fps int
           Maximum framerate in frames per second (0 for no limit).

       -default_fps int
           Default framerate in frames per second when none is specified in the file (0 meaning
           as fast as possible).

   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. It also sets the safe option to 1 if it was -1.

           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.

       "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.

       Options

       This demuxer accepts the following option:

       safe
           If set to 1, reject unsafe file paths. 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.

           -1 is equivalent to 1 if the format was automatically probed and 0 otherwise.

       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.

   flv, live_flv
       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.

               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

       It accepts the following options:

       live_start_index
           segment index to start live streams at (negative values are from the end).

       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.

       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.

   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.

       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 <http://code.google.com/p/game-music-emu/> for more information.

       Some files have multiple tracks. The demuxer will pick the first track by default. The
       track_index option can be used to select a different track. Track indexes start at 0. The
       demuxer exports the number of tracks as tracks meta data entry.

       For very large files, the max_size option may have to be adjusted.

   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/QuickTime
       QuickTime / MP4 demuxer.

       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.

   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.

   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

   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

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 milliseconds.

           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.

   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.

               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.

   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

   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.

   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-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.

       This protocol accepts the following options:

       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).

   gopher
       Gopher protocol.

   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.

       content_type
           Set a specific content type for the POST messages or for listen mode.

       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.

       multiple_requests
           Use persistent connections if set to 1, default is 0.

       post_data
           Set custom HTTP post data.

       referer
           Set the Referer header. Include 'Referer: URL' header in HTTP request.

       user_agent
           Override the User-Agent header. If not specified the protocol will use a string
           describing the libavformat build. ("Lavf/<version>")

       user-agent
           This is a deprecated option, you can use user_agent instead it.

       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.

       reconnect_at_eof
           If set then eof is treated like an error and causes reconnection, this is useful for
           live / endless streams.

       reconnect_streamed
           If set then even streamed/non seekable streams will be reconnected on errors.

       reconnect_delay_max
           Sets the maximum delay in seconds after which to give up reconnecting

       mime_type
           Export the MIME type.

       http_version
           Exports the HTTP response version number. Usually "1.0" or "1.1".

       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.

       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.

       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.

       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>

       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.

               icecast://[<username>[:<password>]@]<server>:<port>/<mountpoint>

   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>]

       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.

       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>

   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_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.

       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.

       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.

           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".

       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.

           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.

           Default value is none.

       allowed_media_types
           Set media types to accept from the server.

           The following flags are accepted:

           video
           audio
           data

           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.

       timeout
           Set maximum timeout (in seconds) to wait for incoming connections.

           A value of -1 means infinite (default). This option implies the rtsp_flags set to
           listen.

       reorder_queue_size
           Set number of packets to buffer for handling of reordered packets.

       stimeout
           Set socket TCP I/O timeout in microseconds.

       user-agent
           Override User-Agent header. If not specified, it defaults to the libavformat
           identifier string.

       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
           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
           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
           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).

       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
           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
           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.

       rw_timeout
           Set raise error timeout for read/write optations.

           This option is only relevant in read mode: if no data arrived in more than this time
           interval, raise error.

       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 doesnXt make sense in Rendezvous connection; the result might be that simply
           one side will override the value from the other side and itXs the matter of luck which
           one would win

       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) thereXs 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

       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=1|0
           Listen for an incoming connection. 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.

       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.

       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.

       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
           64KB.  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.

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.

       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

   bktr
       BSD video input device.

       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. Alternatively
           you can 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.

       bm_v210
           This is a deprecated option, you can use raw_format instead.  If set to 1, video is
           captured in 10 bit v210 instead of uyvy422. Not all Blackmagic devices support this
           option.

       raw_format
           Set the pixel format of the captured video.  Available values are:

           uyvy422
           yuv422p10
           argb
           bgra
           rgb10
       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 mode. Must be unset, half or full.  Defaults to unset.

       timecode_format
           Timecode type to include in the frame and video stream metadata. Must be none,
           rp188vitc, rp188vitc2, rp188ltc, rp188any, vitc, vitc2, or serial. Defaults to none
           (not included).

       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.

       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.

       Examples

       ·   List input devices:

                   ffmpeg -f decklink -list_devices 1 -i dummy

       ·   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 -bm_v210 1 -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.

       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.

       There are two options for the input filename:

               desktop

       or

               title=<window_title>

       The first option will capture the entire desktop, or a fixed region of the desktop. The
       second option 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 -hdvbuffer 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.  Defaults to bgr0.

       format_modifier
           Format modifier to signal on output frames.  This is necessary to import correctly
           into some APIs, but can't be autodetected.  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

   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. Currently only video data is supported. 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 a file (experimental):

                   ffmpeg -f lavfi -i "movie=test.ts[out0+subcc]" -map v frame%08d.png -map s -c copy -f rawvideo 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".

   libndi_newtek
       The libndi_newtek input device provides capture capabilities for using NDI (Network Device
       Interface, standard created by NewTek).

       Input filename is a NDI source name that could be found by sending -find_sources 1 to
       command line - it has no specific syntax but human-readable formatted.

       To enable this input device, you need the NDI SDK and you need to configure with the
       appropriate "--extra-cflags" and "--extra-ldflags".

       Options

       find_sources
           If set to true, print a list of found/available NDI sources and exit.  Defaults to
           false.

       wait_sources
           Override time to wait until the number of online sources have changed.  Defaults to
           0.5.

       allow_video_fields
           When this flag is false, all video that you receive will be progressive.  Defaults to
           true.

       extra_ips
           If is set to list of comma separated ip addresses, scan for sources not only using
           mDNS but also use unicast ip addresses specified by this list.

       Examples

       ·   List input devices:

                   ffmpeg -f libndi_newtek -find_sources 1 -i dummy

       ·   List local and remote input devices:

                   ffmpeg -f libndi_newtek -extra_ips "192.168.10.10" -find_sources 1 -i dummy

       ·   Restream to NDI:

                   ffmpeg -f libndi_newtek -i "DEV-5.INTERNAL.M1STEREO.TV (NDI_SOURCE_NAME_1)" -f libndi_newtek -y NDI_SOURCE_NAME_2

       ·   Restream remote NDI to local NDI:

                   ffmpeg -f libndi_newtek -extra_ips "192.168.10.10" -i "DEV-5.REMOTE.M1STEREO.TV (NDI_SOURCE_NAME_1)" -f libndi_newtek -y NDI_SOURCE_NAME_2

   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
           Specify the number of bytes per frame, by default it is set to 1024.

       fragment_size
           Specify the minimal buffering fragment in PulseAudio, it will affect the audio
           latency. By default it is unset.

       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

       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

       video_size
           Set the video frame size. Default value is "vga".

       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.

       ich, in_channel_count
           Set the number of input channels. Default value is 0. Setting this value is not
           mandatory if the corresponding channel layout in_channel_layout is set.

       och, out_channel_count
           Set the number of output channels. Default value is 0. Setting this value is not
           mandatory if the corresponding channel layout out_channel_layout is set.

       uch, used_channel_count
           Set the number of used input channels. Default value is 0. 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.

       icl, in_channel_layout
       ocl, out_channel_layout
           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. 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.

           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
           Set source width.

       srch
           Set source height.

       dstw
           Set destination width.

       dsth
           Set destination height.

       src_format
           Set source pixel format (must be expressed as an integer).

       dst_format
           Set destination pixel format (must be expressed as an integer).

       src_range
           Select source range.

       dst_range
           Select destination 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.

       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.

       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"

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

       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.

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.

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.

   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.

       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.

   acontrast
       Simple audio dynamic range commpression/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, can be 2nd, 4th or 8th.  Default is 4th.

   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.

   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.

       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.

       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.

       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.

       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.

       b   Set burst fusion, in percentage of window size. Allowed range is 0 to 10. Default
           value is 2.  If any two samples deteced as noise are spaced less than this value then
           any sample inbetween those two samples will be also detected as noise.

       m   Set overlap method.

           It accepts the following values:

           a   Select overlap-add method. Even not interpolated samples are slightly changed with
               this method.

           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.

       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.

       o   Set window overlap, in percentage of window size. Allowed range is from 50 to 95.
           Default value is 75 percent.

       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.

       t   Set threshold value. Allowed range is from 1 to 100.  Default value is 10. Higher
           values make clip detection less aggressive.

       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.

       m   Set overlap method.

           It accepts the following values:

           a   Select overlap-add method. Even not interpolated samples are slightly changed with
               this method.

           s   Select overlap-save method. Not interpolated samples remain unchanged.

           Default value is "a".

   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.

       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

   aderivative, aintegral
       Compute derivative/integral of audio stream.

       Applying both filters one after another produces original audio.

   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 sound 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 50Xs (FM).

           75fm
               select 75Xs (FM).

           50kf
               select 50Xs (FM-KF).

           75kf
               select 75Xs (FM-KF).

   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)

   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

       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.

       nr  Set the noise reduction in dB, allowed range is 0.01 to 97.  Default value is 12 dB.

       nf  Set the noise floor in dB, allowed range is -80 to -20.  Default value is -50 dB.

       nt  Set the noise type.

           It accepts the following values:

           w   Select white noise.

           v   Select vinyl noise.

           s   Select shellac noise.

           c   Select custom noise, defined in "bn" option.

               Default value is white noise.

       bn  Set custom band noise for every one of 15 bands.  Bands are separated by ' ' or '|'.

       rf  Set the residual floor in dB, allowed range is -80 to -20.  Default value is -38 dB.

       tn  Enable noise tracking. By default is disabled.  With this enabled, noise floor is
           automatically adjusted.

       tr  Enable residual tracking. By default is disabled.

       om  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.

       Commands

       This filter supports the following commands:

       sample_noise, sn
           Start or stop measuring noise profile.  Syntax for the command is : "start" or "stop"
           string.  After measuring noise profile is stopped it will be automatically applied in
           filtering.

       noise_reduction, nr
           Change noise reduction. Argument is single float number.  Syntax for the command is :
           "noise_reduction"

       noise_floor, nf
           Change noise floor. Argument is single float number.  Syntax for the command is :
           "noise_floor"

       output_mode, om
           Change output mode operation.  Syntax for the command is : "i", "o" or "n" string.

   afftfilt
       Apply arbitrary expressions to samples in frequency domain.

       real
           Set frequency domain real expression for each separate channel separated by '|'.
           Default is "1".  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 '|'.
           If not set, real option is used.

           Each expression in real and imag can contain the following constants:

           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

       win_size
           Set window size.

           It accepts the following values:

           w16
           w32
           w64
           w128
           w256
           w512
           w1024
           w2048
           w4096
           w8192
           w16384
           w32768
           w65536

           Default is "w4096"

       win_func
           Set window function. 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="1-clip((b/nb)*b,0,1)"

   afir
       Apply an arbitrary Frequency 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 and ambisonics.

       This filter uses second stream as FIR coefficients.  If second stream holds single
       channel, it will be used for all input channels in first stream, otherwise number of
       channels in second stream must be same as number of channels in 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
           Enable applying gain measured from power of IR.

           Set which approach to use for auto gain measurement.

           none
               Do not apply any gain.

           peak
               select peak gain, very conservative approach. This is default value.

           dc  select DC gain, limited application.

           gn  select gain to noise approach, this is most popular one.

       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 gtype 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
           Show IR frequency reponse, magnitude(magenta) and 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.

       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

   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
           A '|'-separated list of requested sample formats.

       sample_rates
           A '|'-separated list of requested sample rates.

       channel_layouts
           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

   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.

       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.

       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".

   aiir
       Apply an arbitrary Infinite Impulse Response filter.

       It accepts the following parameters:

       z   Set numerator/zeros coefficients.

       p   Set denominator/poles coefficients.

       k   Set channels gains.

       dry_gain
           Set input gain.

       wet_gain
           Set output gain.

       f   Set coefficients format.

           tf  transfer function

           zp  Z-plane zeros/poles, cartesian (default)

           pr  Z-plane zeros/poles, polar radians

           pd  Z-plane zeros/poles, polar degrees

       r   Set kind of processing.  Can be "d" - direct or "s" - serial cascading. Defauls is
           "s".

       e   Set filtering precision.

           dbl double-precision floating-point (default)

           flt single-precision floating-point

           i32 32-bit integers

           i16 16-bit integers

       response
           Show IR frequency reponse, magnitude and phase 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" 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 arround 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

   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.

       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.

       channels, c
           Specify which channels to filter, by default all available are filtered.

       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"

   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.

   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.

       For example

               ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex amix=inputs=3:duration=first:dropout_transition=3 OUTPUT

       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.

       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 sequence.  Each weight is separated by
           space. By default all inputs have same weight.

   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 herz.
           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=...

   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.

       If neither the pad_len nor the whole_len option is set, the filter will add silence to the
       end of the input stream 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

   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

   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.

       pos position of the frame in the input stream, -1 if this information in unavailable
           and/or meaningless (for example in case of synthetic audio)

       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.

   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 "[0.01 - 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: DC_offset Min_level Max_level Min_difference
           Max_difference Mean_difference RMS_difference Peak_level RMS_peak RMS_trough
           Crest_factor Flat_factor Peak_count Bit_depth Dynamic_range Zero_crossings
           Zero_crossings_rate

           and for Overall: DC_offset Min_level Max_level Min_difference Max_difference
           Mean_difference RMS_difference Peak_level RMS_level RMS_peak RMS_trough Flat_factor
           Peak_count Bit_depth Number_of_samples

           For example full key look like this "lavfi.astats.1.DC_offset" or this
           "lavfi.astats.Overall.Peak_count".

           For description what each key means read below.

       reset
           Set number of frame after which stats are going to be recalculated.  Default is
           disabled.

       A description of each shown parameter follows:

       DC offset
           Mean amplitude displacement from zero.

       Min level
           Minimal sample level.

       Max level
           Maximal sample level.

       Min difference
           Minimal difference between two consecutive samples.

       Max difference
           Maximal difference between two consecutive samples.

       Mean difference
           Mean difference between two consecutive samples.  The average of each difference
           between two consecutive samples.

       RMS difference
           Root Mean Square difference between two consecutive samples.

       Peak level dB
       RMS level dB
           Standard peak and RMS level measured in dBFS.

       RMS peak dB
       RMS trough dB
           Peak and trough values for RMS level measured over a short window.

       Crest factor
           Standard ratio of peak to RMS level (note: not in dB).

       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).

       Peak count
           Number of occasions (not the number of samples) that the signal attained either Min
           level or Max level.

       Bit depth
           Overall bit depth of audio. Number of bits used for each sample.

       Dynamic range
           Measured dynamic range of audio in dB.

       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.

   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)

   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

   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.

       channels, c
           Specify which channels to filter, by default all available are filtered.

       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"

   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.

       channels, c
           Specify which channels to filter, by default all available are filtered.

       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"

   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.

       channels, c
           Specify which channels to filter, by default all available are filtered.

       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"

   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"

   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.

       channel_layout
           The channel layout of the output stream.

       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 location.
       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 distance of
       ~30 cm between microphones makes one microphone to capture signal in antiphase to another
       microphone. That makes the final mix sounding 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.

       It 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 degree in Celsius. This is the temperature of the environment.
           Default is 20.

   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.

       level_in
           Set input gain. Default is 0.9.

       level_out
           Set output gain. Default is 1.

   crystalizer
       Simple algorithm to expand audio dynamic range.

       The filter accepts the following options:

       i   Sets the intensity of effect (default: 2.0). Must be in range between 0.0 (unchanged
           sound) to 10.0 (maximum effect).

       c   Enable clipping. By default is enabled.

   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.

   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.

       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.

       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.

       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.

       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.

       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.

       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.

       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.

       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.

       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.

   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.

       channels, c
           Specify which channels to filter, by default all available are filtered.

       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"

   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.

   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 -lavfi-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],[a:0][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 -lavfi-complex "amovie=minp.wav[hrirs],[a:0][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.

       channels, c
           Specify which channels to filter, by default all available are filtered.

       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"

   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.

       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. To accurately detect true peaks, the
       audio stream will be upsampled to 192 kHz unless the normalization mode is linear.  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 - 20.0. 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 linearly if possible.  measured_I, measured_LRA, measured_TP, and
           measured_thresh must also to be specified in order to use this mode.  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.

       channels, c
           Specify which channels to filter, by default all available are filtered.

       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"

   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

   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".

   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

   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.

       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.

       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.

       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.

       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.

   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 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).

       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 in start of multi-channel audio.  Can be any
           or all. Default is any.  With any, any sample that is detected as non-silence will
           cause stopped trimming of silence.  With all, only if all channels are detected as
           non-silence will cause stopped trimming of silence.

       stop_periods
           Set the count for trimming silence from the end of audio.  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 start_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 in end of multi-channel audio.  Can be any
           or all. Default is any.  With any, any sample that is detected as non-silence will
           cause stopped trimming of silence.  With all, only if all channels are detected as
           non-silence will cause stopped trimming of silence.

       detection
           Set how is silence detected. Can be "rms" or "peak". Second is faster and works better
           with digital silence which is exactly 0.  Default value is "rms".

       window
           Set duration in number of seconds used to calculate size of window in number of
           samples for detecting silence.  Default value is 0.02. Allowed range is from 0 to 10.

       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

   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.

       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"

   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.

       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.

       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.

   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.

       fc_in
           Set front center input volume. By default, this is 1.

       fc_out
           Set front 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.

   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.

       channels, c
           Specify which channels to filter, by default all available are filtered.

       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"

   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.

   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.

       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

       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.

       replaygain_noclip
           Prevent clipping by limiting the gain applied.

           Default value for replaygain_noclip is 1.

       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. The input is not modified. 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/asrc_abuffer.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)"

   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.

       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 and
           violet. 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.

       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.

   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]

       Since this filter is designed for reconstruction, it operates on frame sequences without
       considering timestamps, and terminates when either input reaches end of stream. This will
       cause problems if your encoding pipeline drops frames. If you're trying to apply an image
       as an overlay to a video stream, consider the overlay filter instead.

   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 differrence greater or equal to this
           value will not alter source pixel. Default is 10.  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.

   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.

   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.

   bbox
       Compute the bounding box for the non-black pixels in the input frame luminance plane.

       This filter computes the bounding box containing all the pixels with a luminance 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 luminance value. Default is 16.

   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. Output lines contains the time for the
       start, end and duration of the detected black interval expressed in seconds.

       In order to display the output lines, you need to set the loglevel at least to the
       AV_LOG_INFO value.

       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 luminance value for which a pixel is
           considered "black". The provided value is scaled according to the following equation:

                   <absolute_threshold> = <luminance_minimum_value> + <pixel_black_th> * <luminance_range_size>

           luminance_range_size and luminance_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, tblend
       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
           grainmerge
           and
           average
           burn
           darken
           difference
           grainextract
           divide
           dodge
           freeze
           exclusion
           extremity
           glow
           hardlight
           hardmix
           heat
           lighten
           linearlight
           multiply
           multiply128
           negation
           normal
           or
           overlay
           phoenix
           pinlight
           reflect
           screen
           softlight
           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

   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 algorith 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. Accept one of the following values:

           0, all
               Deinterlace all frames.

           1, interlaced
               Only deinterlace frames marked as interlaced.

           The default value is "all".

   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.

       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.

   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.

       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

   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
       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.

   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:

       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.

       Examples

       ·   Add red color cast to shadows:

                   colorbalance=rs=.3

   colorkey
       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 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

   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.

       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

   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]".

       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

   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

   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 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.

       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

   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

       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 area of the input
       video.

       It accepts the following parameters:

       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.

       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.

   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 (using a
       natural cubic spline interpolation) will be define to pass smoothly through all these new
       coordinates. The new defined points needs to be strictly increasing over the x-axis, and
       their x and y values must be in the [0;1] interval.  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.

       To avoid some filtergraph syntax conflicts, each key points list need to be defined using
       the following syntax: "x0/y0 x1/y1 x2/y2 ...".

       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.

   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.

   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

   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.

   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.

   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.

   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.

       band, t
           Specify the thickness of the fuzzy edge of the rectangle (added to w and h). The
           default value is 1. This option is deprecated, setting higher values should no longer
           be necessary and is not recommended.

       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, and a band of size 10:

                   delogo=x=0:y=0:w=100:h=77:band=10

   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.

   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

   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

   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.

       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

   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

   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".  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 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 of the border to be drawn around the box using box.
           The default value of line_spacing is 0.

       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".

       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.

       reload
           If set to 1, the textfile will be reloaded before each frame.  Be sure to update it
           atomically, or it may be read partially, or even fail.

       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

       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 each other, so you can for
           example specify "y=x/dar".

       Text expansion

       If expansion is set to "strftime", the filter recognizes strftime() sequences in the
       provided text and expands them accordingly. Check the documentation of strftime(). This
       feature is deprecated.

       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
       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() format string.

       localtime
           The time at which the filter is running, expressed in the local time zone.  It can
           accept an argument: a strftime() format string.

       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.

       n, frame_num
           The frame number, starting from 0.

       pict_type
           A 1 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() format string.  By default, YYYY-MM-DD HH:MM:SS format will be used.

       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'

       ·   Print the date of a real-time encoding (see strftime(3)):

                   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

       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/>.

   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

   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 "-2.0" to 2.0.
           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

       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

   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

   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.

   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.

   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

   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.

       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)))'

   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, Default is 4, can be 3, 4, 5 or 6.  Actual size of block in pixels
           is 2 to power of block, so by default block size in pixels is 2^4 which is 16.

       overlap
           Set block overlap. Default is 0.5. Allowed range is from 0.2 to 0.8.

       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.

   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 line starts with "#" or ";" that line is skipped.

       mode
           Can be item "absolute" or "relative". Default is "absolute".

       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

   fifo, afifo
       Buffer input images and send them when they are requested.

       It is mainly useful when auto-inserted by the libavfilter framework.

       It does not take parameters.

   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

           fixed
               fill pixels with constant value

           Default is smear.

       color
           Set color for pixels in fixed mode. Default is black.

   find_rect
       Find a rectangular object

       It accepts the following options:

       object
           Filepath of the object image, needs to be in gray8.

       threshold
           Detection threshold, default is 0.5.

       mipmaps
           Number of mipmaps, default is 3.

       xmin, ymin, xmax, ymax
           Specifies the rectangle in which to search.

       Examples

       ·   Generate a representative palette of a given video using ffmpeg:

                   ffmpeg -i file.ts -vf find_rect=newref.pgm,cover_rect=cover.jpg:mode=cover new.mkv

   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

       ·   Generate a representative palette of a given video using ffmpeg:

                   ffmpeg -i file.ts -vf find_rect=newref.pgm,cover_rect=cover.jpg:mode=cover new.mkv

   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".

       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. 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.

   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>

   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 X 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).

   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. Defauls 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".

   geq
       Apply generic equation to each pixel.

       The filter accepts the following options:

       lum_expr, lum
           Set the luminance 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 luminance 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 luminance 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.

       For functions, if x and y are outside the area, the value will be automatically clipped to
       the closer edge.

       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, agraphmonitor
       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, can be fulll or compact.  In compact mode only filters with some
           queued frames have displayed stats.

       flags, f
           Set flags which enable which stats are shown in video.

           Available values for flags are:

           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.

           pts Display current filtered frame pts.

           time
               Display current filtered frame time.

           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.

       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.

   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 euqal 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

   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:

       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).

       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>.

       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.

       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.

   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.

   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 accept 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.

   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.

   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.

   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

   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.

   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.

   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

   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.

       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.

   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.

       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.

       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).

       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

   libvmaf
       Obtain the VMAF (Video Multi-Method Assessment Fusion) score between two input videos.

       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 --enable-version3".  If no
       model path is specified it uses the default model: "vmaf_v0.6.1.pkl".

       The filter has following options:

       model_path
           Set the model path which is to be used for SVM.  Default value: "vmaf_v0.6.1.pkl"

       log_path
           Set the file path to be used to store logs.

       log_fmt
           Set the format of the log file (xml or json).

       enable_transform
           Enables transform for computing vmaf.

       phone_model
           Invokes the phone model which will generate VMAF scores higher than in the regular
           model, which is more suitable for laptop, TV, etc. viewing conditions.

       psnr
           Enables computing psnr along with vmaf.

       ssim
           Enables computing ssim along with vmaf.

       ms_ssim
           Enables computing ms_ssim along with vmaf.

       pool
           Set the pool method (mean, min or harmonic mean) to be used for computing vmaf.

       n_threads
           Set number of threads to be used when computing vmaf.

       n_subsample
           Set interval for frame subsampling used when computing vmaf.

       enable_conf_interval
           Enables confidence interval.

       This filter also supports the framesync options.

       On the below examples the input file main.mpg being processed is compared with the
       reference file ref.mpg.

               ffmpeg -i main.mpg -i ref.mpg -lavfi libvmaf -f null -

       Example with options:

               ffmpeg -i main.mpg -i ref.mpg -lavfi libvmaf="psnr=1:enable-transform=1" -f null -

   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.

   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.

       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

       interp
           Select interpolation mode.

           Available values are:

           nearest
               Use values from the nearest defined point.

           linear
               Interpolate values using the linear interpolation.

           cubic
               Interpolate values using the cubic interpolation.

   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

       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.

       This filter also supports the framesync options.

   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.

       softness
           Set the range of softness. Default value is 0.  Use this to control gradual transition
           from zero to full transparency.

   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/luminance 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 "val".

       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 luminance:

                   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 luminance 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

       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".

       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.

   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.

   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.

   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".

       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 the them less
                   blur. 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 5.0.

   mix
       Mix several video input streams into one video stream.

       A description of the accepted options follows.

       nb_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.

       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.

   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.

       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.

   negate
       Negate (invert) the input video.

       It accepts the following option:

       negate_alpha
           With value 1, it negates the alpha component, if present. Default value is 0.

   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.

       p   Set patch size.

       pc  Same as p but for chroma planes.

           The default value is 0 and means automatic.

       r   Set research size.

       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   weights trained to minimize absolute error

           s   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

           Default is "new".

       fapprox
           Set various debugging flags.

   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).

       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".

   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 depend 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.

       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 YUV420 output

           yuv422
               force YUV422 output

           yuv444
               force YUV444 output

           rgb force packed RGB output

           gbrp
               force planar RGB 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

       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, pos, 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]

   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)

           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.

   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.

   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.

   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 luminance filtering only (no chrominance).

       n/noluma
           Do chrominance filtering only (no luminance).

       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 luminance 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 luminance 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.

   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 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));
                   }

   pseudocolor
       Alter frame colors in video with pseudocolors.

       This filter accept 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

       i   set component to use as base for altering colors

       Each of them 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".

       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.

       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.

   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)

   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.

       mac Set minimal acceptable amplitude change for sync codes detection.  Default is 0.2.
           Allowed range is "[0.001 - 1]".

       spw Set the ratio of width reserved for sync code detection.  Default is 0.27. Allowed
           range is "[0.01 - 0.7]".

       mhd Set the max peaks height difference for sync code detection.  Default is 0.1. Allowed
           range is "[0.0 - 0.5]".

       mpd Set max peaks period difference for sync code detection.  Default is 0.1. Allowed
           range is "[0.0 - 0.5]".

       msd Set the first two max start code bits differences.  Default is 0.02. Allowed range is
           "[0.0 - 0.5]".

       bhd Set the minimum ratio of bits height compared to 3rd start code bit.  Default is 0.75.
           Allowed range is "[0.01 - 1]".

       th_w
           Set the white color threshold. Default is 0.35. Allowed range is "[0.1 - 1]".

       th_b
           Set the black color threshold. Default is 0.15. Allowed range is "[0.0 - 0.5]".

       chp Enable checking the parity bit. In the event of a parity error, the filter will output
           0x00 for that character. Default is false.

       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=pkt_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.

   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

   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.

   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, or any of the options supported by the
       libswscale scaler.

       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
               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.

       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).

       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.

       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.

       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

       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_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

   scale2ref
       Scale (resize) the input video, based on a reference video.

       See the scale filter for available options, scale2ref supports the same but uses the
       reference video instead of the main input as basis. scale2ref 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_hsub
       main_vsub
           The main input video's horizontal and vertical chroma subsample values.  For example
           for the pixel format "yuv422p" hsub is 2 and vsub is 1.

       Examples

       ·   Scale a subtitle stream (b) to match the main video (a) in size before overlaying

                   'scale2ref[b][a];[a][b]overlay'

   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, an expression, or a string of the
           form num:den, where num and den are the numerator and denominator of the aspect ratio.
           If the parameter is not specified, it is assumed the value "0".  In case the form
           "num:den" is used, the ":" character should be escaped.

       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:

       E, PI, PHI
           These are approximated values for the mathematical constants e (Euler's number), pi
           (Greek pi), and phi (the golden ratio).

       w, h
           The input width and height.

       a   These are the 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 transfert.  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

   showinfo
       Show a line containing various information for each input video frame.  The input video 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, 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.

       pos The position of the frame in the input stream, or -1 if this information is
           unavailable and/or meaningless (for example in case of synthetic video).

       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]".

   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

   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 -

   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.

       If a chroma option is not explicitly set, the corresponding luma value is set.

   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.

       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 -

   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 above-below (left eye above, right eye below)

           abr above-below (right eye above, left eye below)

           ab2l
               above-below with half height resolution (left eye above, right eye below)

           ab2r
               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 above-below (left eye above, right eye below)

           abr above-below (right eye above, left eye below)

           ab2l
               above-below with half height resolution (left eye above, right eye below)

           ab2r
               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

   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.

   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).

   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 generation are provided in the repository 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:

           native
               Native implementation of DNN loading and execution.

           tensorflow
               TensorFlow backend. To enable this backend you need to install the TensorFlow for
               C library (see <https://www.tensorflow.org/install/install_c>) and configure
               FFmpeg with "--enable-libtensorflow"

           Default value is native.

       model
           Set path to model file specifying network architecture and its parameters.  Note that
           different backends use different file formats. TensorFlow backend can load files for
           both formats, while native 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.

   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 ",".

       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

   swapuv
       Swap U & V plane.

   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

   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:

       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.

       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 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.

       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.

       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.

       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.

       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.

       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

   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, vlfp
               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, cvlfp
               Enable complex vertical low-pass filtering.  This will slightly less reduce
               interlace 'twitter' and Moire patterning but better retain detail and subjective
               sharpness impression.

           Vertical low-pass filtering can only be enabled for mode interleave_top and
           interleave_bottom.

   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.

       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

   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.

   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.

       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

   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.

       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).

   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.

   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
               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
       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.

   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.

       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 and max 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.

   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 filters of
       VMAF.

       The obtained average motion score is printed through the logging system.

       In the below example the input file ref.mpg is being processed and score is computed.

               ffmpeg -i ref.mpg -lavfi 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 accept 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.

   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.

       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.

       deint
           Specify which frames to deinterlace. Accept one of the following values:

           all Deinterlace all frames,

           interlaced
               Only deinterlace frames marked as interlaced.

           Default value is all.

   waveform
       Video waveform monitor.

       The waveform monitor plots color component intensity. By default luminance 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 luminance 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.

           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.

       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.

   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.

   xstack
       Stack video inputs into custom layout.

       All streams must be of same pixel format.

       The filter accept the following option:

       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.

       shortest
           If set to 1, force the output to terminate when the shortest input terminates. Default
           value is 0.

       Examples

       ·   Display 4 inputs into 2x2 grid, note that if inputs are of different sizes unused gaps
           might appear, as not all of output video is used.

                   xstack=inputs=4:layout=0_0|0_h0|w0_0|w0_h0

       ·   Display 4 inputs into 1x4 grid, note that if inputs are of different sizes unused gaps
           might appear, as not all of output video is used.

                   xstack=inputs=4:layout=0_0|0_h0|0_h0+h1|0_h0+h1+h2

       ·   Display 9 inputs into 3x3 grid, note that if inputs are of different sizes unused gaps
           might appear, as not all of output video is used.

                   xstack=inputs=9:layout=w3_0|w3_h0+h2|w3_h0|0_h4|0_0|w3+w1_0|0_h1+h2|w3+w1_h0|w3+w1_h1+h2

   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. Accept 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. Accept one of the following values:

           0, all
               Deinterlace all frames.

           1, interlaced
               Only deinterlace frames marked as interlaced.

           The default value is "all".

   zoompan
       Apply Zoom & Pan effect.

       This filter accepts the following options:

       zoom, z
           Set the zoom expression. 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.

       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.

       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 1.5 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 1.5 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)'

   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.

       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.

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/vsrc_buffer.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.

       pixel_aspect, sar
           The sample (pixel) aspect ratio of the input video.

       sws_param
           Specify the optional parameters to be used for the scale filter which is automatically
           inserted when an input change is detected in the input size or format.

       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[:sws_param]

   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.

   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 cound 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

           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

   allrgb, allyuv, color, 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 "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.

       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.

       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 luminance 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);
                   }

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.

   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.

   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.  Defauls 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".

   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.

   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
       monoaural 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.

           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]'

   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

   drawgraph, adrawgraph
       Draw a graph using input video or audio 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".

           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

   ebur128
       EBU R128 scanner filter. This filter takes an audio stream as input and outputs it
       unchanged. 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 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:

           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.

       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.

       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

   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.

       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
               Float representation of "value" from metadata key.

           VALUE2
               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.

       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.

   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 video frame, expressed in TB units.
           It's NAN if undefined.

       t   The PTS of the filtered video frame, expressed in seconds. It's NAN if undefined.

       prev_pts
           The PTS of the previously filtered video frame. It's NAN if undefined.

       prev_selected_pts
           The PTS of the last previously filtered video frame. It's NAN if undefined.

       prev_selected_t
           The PTS of the last previously selected video frame, expressed in seconds. It's NAN if
           undefined.

       start_pts
           The PTS of the first video frame in the video. It's NAN if undefined.

       start_t
           The time of the first video frame in the video. It's NAN if undefined.

       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)

       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.

       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.

       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

       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.

       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)

       ·   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

   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

   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".

       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.

           It accepts the following values:

           w16
           w32
           w64
           w128
           w256
           w512
           w1024
           w2048
           w4096
           w8192
           w16384
           w32768
           w65536

           Default is "w2048"

       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

           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.

   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

           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

           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.

       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

           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".

       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.

       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

           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.

       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

           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.

       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.

       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
       Sythesize 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 its 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.

   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.

       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.

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
       (git://source.ffmpeg.org/ffmpeg), e.g. by typing the command git log in the FFmpeg source
       directory, or browsing the online repository at <http://source.ffmpeg.org>.

       Maintainers for the specific components are listed in the file MAINTAINERS in the source
       code tree.

                                                                                   FFPROBE-ALL(1)