Ubuntu Manpage: ffmpeg-formats

Provided by: ffmpeg_3.4.11-0ubuntu0.1_amd64

NAME

       ffmpeg-formats - FFmpeg formats

DESCRIPTION

       This document describes the supported formats (muxers and demuxers) provided by the
       libavformat library.

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 (input/output)
Set format flags.

Possible values:

ignidx
Ignore index.

fastseek
Enable fast, but inaccurate seeks for some formats.

genpts
Generate PTS.

nofillin
Do not fill in missing values that can be exactly calculated.

noparse
Disable AVParsers, this needs "+nofillin" too.

igndts
Ignore DTS.

discardcorrupt
Discard corrupted frames.

sortdts
Try to interleave output packets by DTS.

keepside
Do not merge side data.

latm
Enable RTP MP4A-LATM payload.

nobuffer
Reduce the latency introduced by optional buffering

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.

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.

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

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.

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.

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.

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.

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

MUXERS

Muxers are configured elements in FFmpeg which allow writing multimedia streams to a
particular type of file.

When you configure your FFmpeg build, all the supported muxers are enabled by default. You
can list all available muxers using the configure option "--list-muxers".

You can disable all the muxers with the configure option "--disable-muxers" and
selectively enable / disable single muxers with the options "--enable-muxer=MUXER" /
"--disable-muxer=MUXER".

The option "-muxers" of the ff* tools will display the list of enabled muxers. Use
"-formats" to view a combined list of enabled demuxers and muxers.

A description of some of the currently available muxers follows.

aiff
Audio Interchange File Format muxer.

Options

It accepts the following options:

write_id3v2
Enable ID3v2 tags writing when set to 1. Default is 0 (disabled).

id3v2_version
Select ID3v2 version to write. Currently only version 3 and 4 (aka. ID3v2.3 and
ID3v2.4) are supported. The default is version 4.

asf
Advanced Systems Format muxer.

Note that Windows Media Audio (wma) and Windows Media Video (wmv) use this muxer too.

Options

It accepts the following options:

packet_size
Set the muxer packet size. By tuning this setting you may reduce data fragmentation or
muxer overhead depending on your source. Default value is 3200, minimum is 100,
maximum is 64k.

avi
Audio Video Interleaved muxer.

Options

It accepts the following options:

reserve_index_space
Reserve the specified amount of bytes for the OpenDML master index of each stream
within the file header. By default additional master indexes are embedded within the
data packets if there is no space left in the first master index and are linked
together as a chain of indexes. This index structure can cause problems for some use
cases, e.g. third-party software strictly relying on the OpenDML index specification
or when file seeking is slow. Reserving enough index space in the file header avoids
these problems.

The required index space depends on the output file size and should be about 16 bytes
per gigabyte. When this option is omitted or set to zero the necessary index space is
guessed.

write_channel_mask
Write the channel layout mask into the audio stream header.

This option is enabled by default. Disabling the channel mask can be useful in
specific scenarios, e.g. when merging multiple audio streams into one for
compatibility with software that only supports a single audio stream in AVI (see the
"amerge" section in the ffmpeg-filters manual).

chromaprint
Chromaprint fingerprinter

This muxer feeds audio data to the Chromaprint library, which generates a fingerprint for
the provided audio data. It takes a single signed native-endian 16-bit raw audio stream.

Options

silence_threshold
Threshold for detecting silence, ranges from 0 to 32767. -1 for default (required for
use with the AcoustID service).

algorithm
Algorithm index to fingerprint with.

fp_format
Format to output the fingerprint as. Accepts the following options:

raw Binary raw fingerprint

compressed
Binary compressed fingerprint

base64
Base64 compressed fingerprint

crc
CRC (Cyclic Redundancy Check) testing format.

This muxer computes and prints the Adler-32 CRC of all the input audio and video frames.
By default audio frames are converted to signed 16-bit raw audio and video frames to raw
video before computing the CRC.

The output of the muxer consists of a single line of the form: CRC=0xCRC, where CRC is a
hexadecimal number 0-padded to 8 digits containing the CRC for all the decoded input
frames.

See also the hash and framemd5 muxers.

mov, mp4, ismv
MOV/MP4/ISMV (Smooth Streaming) muxer.

The mov/mp4/ismv muxer supports fragmentation. Normally, a MOV/MP4 file has all the
metadata about all packets stored in one location (written at the end of the file, it can
be moved to the start for better playback by adding faststart to the movflags, or using
the qt-faststart tool). A fragmented file consists of a number of fragments, where packets
and metadata about these packets are stored together. Writing a fragmented file has the
advantage that the file is decodable even if the writing is interrupted (while a normal
MOV/MP4 is undecodable if it is not properly finished), and it requires less memory when
writing very long files (since writing normal MOV/MP4 files stores info about every single
packet in memory until the file is closed). The downside is that it is less compatible
with other applications.

Options

Fragmentation is enabled by setting one of the AVOptions that define how to cut the file
into fragments:

-moov_size bytes
Reserves space for the moov atom at the beginning of the file instead of placing the
moov atom at the end. If the space reserved is insufficient, muxing will fail.

-movflags frag_keyframe
Start a new fragment at each video keyframe.

-frag_duration duration
Create fragments that are duration microseconds long.

-frag_size size
Create fragments that contain up to size bytes of payload data.

-movflags frag_custom
Allow the caller to manually choose when to cut fragments, by calling
"av_write_frame(ctx, NULL)" to write a fragment with the packets written so far. (This
is only useful with other applications integrating libavformat, not from ffmpeg.)

-min_frag_duration duration
Don't create fragments that are shorter than duration microseconds long.

If more than one condition is specified, fragments are cut when one of the specified
conditions is fulfilled. The exception to this is "-min_frag_duration", which has to be
fulfilled for any of the other conditions to apply.

Additionally, the way the output file is written can be adjusted through a few other
options:

-movflags empty_moov
Write an initial moov atom directly at the start of the file, without describing any
samples in it. Generally, an mdat/moov pair is written at the start of the file, as a
normal MOV/MP4 file, containing only a short portion of the file. With this option
set, there is no initial mdat atom, and the moov atom only describes the tracks but
has a zero duration.

This option is implicitly set when writing ismv (Smooth Streaming) files.

-movflags separate_moof
Write a separate moof (movie fragment) atom for each track. Normally, packets for all
tracks are written in a moof atom (which is slightly more efficient), but with this
option set, the muxer writes one moof/mdat pair for each track, making it easier to
separate tracks.

This option is implicitly set when writing ismv (Smooth Streaming) files.

-movflags faststart
Run a second pass moving the index (moov atom) to the beginning of the file. This
operation can take a while, and will not work in various situations such as fragmented
output, thus it is not enabled by default.

-movflags rtphint
Add RTP hinting tracks to the output file.

-movflags disable_chpl
Disable Nero chapter markers (chpl atom). Normally, both Nero chapters and a
QuickTime chapter track are written to the file. With this option set, only the
QuickTime chapter track will be written. Nero chapters can cause failures when the
file is reprocessed with certain tagging programs, like mp3Tag 2.61a and iTunes 11.3,
most likely other versions are affected as well.

-movflags omit_tfhd_offset
Do not write any absolute base_data_offset in tfhd atoms. This avoids tying fragments
to absolute byte positions in the file/streams.

-movflags default_base_moof
Similarly to the omit_tfhd_offset, this flag avoids writing the absolute
base_data_offset field in tfhd atoms, but does so by using the new default-base-is-
moof flag instead. This flag is new from 14496-12:2012. This may make the fragments
easier to parse in certain circumstances (avoiding basing track fragment location
calculations on the implicit end of the previous track fragment).

-write_tmcd
Specify "on" to force writing a timecode track, "off" to disable it and "auto" to
write a timecode track only for mov and mp4 output (default).

-movflags negative_cts_offsets
Enables utilization of version 1 of the CTTS box, in which the CTS offsets can be
negative. This enables the initial sample to have DTS/CTS of zero, and reduces the
need for edit lists for some cases such as video tracks with B-frames. Additionally,
eases conformance with the DASH-IF interoperability guidelines.

Example

Smooth Streaming content can be pushed in real time to a publishing point on IIS with this
muxer. Example:

ffmpeg -re <<normal input/transcoding options>> -movflags isml+frag_keyframe -f ismv http://server/publishingpoint.isml/Streams(Encoder1)

Audible AAX

Audible AAX files are encrypted M4B files, and they can be decrypted by specifying a 4
byte activation secret.

ffmpeg -activation_bytes 1CEB00DA -i test.aax -vn -c:a copy output.mp4

mp3
The MP3 muxer writes a raw MP3 stream with the following optional features:

• An ID3v2 metadata header at the beginning (enabled by default). Versions 2.3 and 2.4
are supported, the "id3v2_version" private option controls which one is used (3 or 4).
Setting "id3v2_version" to 0 disables the ID3v2 header completely.

The muxer supports writing attached pictures (APIC frames) to the ID3v2 header. The
pictures are supplied to the muxer in form of a video stream with a single packet.
There can be any number of those streams, each will correspond to a single APIC frame.
The stream metadata tags title and comment map to APIC description and picture type
respectively. See <http://id3.org/id3v2.4.0-frames> for allowed picture types.

Note that the APIC frames must be written at the beginning, so the muxer will buffer
the audio frames until it gets all the pictures. It is therefore advised to provide
the pictures as soon as possible to avoid excessive buffering.

• A Xing/LAME frame right after the ID3v2 header (if present). It is enabled by default,
but will be written only if the output is seekable. The "write_xing" private option
can be used to disable it. The frame contains various information that may be useful
to the decoder, like the audio duration or encoder delay.

• A legacy ID3v1 tag at the end of the file (disabled by default). It may be enabled
with the "write_id3v1" private option, but as its capabilities are very limited, its
usage is not recommended.

Examples:

Write an mp3 with an ID3v2.3 header and an ID3v1 footer:

ffmpeg -i INPUT -id3v2_version 3 -write_id3v1 1 out.mp3

To attach a picture to an mp3 file select both the audio and the picture stream with
"map":

ffmpeg -i input.mp3 -i cover.png -c copy -map 0 -map 1
-metadata:s:v title="Album cover" -metadata:s:v comment="Cover (Front)" out.mp3

Write a "clean" MP3 without any extra features:

ffmpeg -i input.wav -write_xing 0 -id3v2_version 0 out.mp3

mpegts
MPEG transport stream muxer.

This muxer implements ISO 13818-1 and part of ETSI EN 300 468.

The recognized metadata settings in mpegts muxer are "service_provider" and
"service_name". If they are not set the default for "service_provider" is FFmpeg and the
default for "service_name" is Service01.

Options

The muxer options are:

mpegts_transport_stream_id integer
Set the transport_stream_id. This identifies a transponder in DVB. Default is 0x0001.

mpegts_original_network_id integer
Set the original_network_id. This is unique identifier of a network in DVB. Its main
use is in the unique identification of a service through the path Original_Network_ID,
Transport_Stream_ID. Default is 0x0001.

mpegts_service_id integer
Set the service_id, also known as program in DVB. Default is 0x0001.

mpegts_service_type integer
Set the program service_type. Default is "digital_tv". Accepts the following options:

hex_value
Any hexdecimal value between 0x01 to 0xff as defined in ETSI 300 468.

digital_tv
Digital TV service.

digital_radio
Digital Radio service.

teletext
Teletext service.

advanced_codec_digital_radio
Advanced Codec Digital Radio service.

mpeg2_digital_hdtv
MPEG2 Digital HDTV service.

advanced_codec_digital_sdtv
Advanced Codec Digital SDTV service.

advanced_codec_digital_hdtv
Advanced Codec Digital HDTV service.

mpegts_pmt_start_pid integer
Set the first PID for PMT. Default is 0x1000. Max is 0x1f00.

mpegts_start_pid integer
Set the first PID for data packets. Default is 0x0100. Max is 0x0f00.

mpegts_m2ts_mode boolean
Enable m2ts mode if set to 1. Default value is "-1" which disables m2ts mode.

muxrate integer
Set a constant muxrate. Default is VBR.

pes_payload_size integer
Set minimum PES packet payload in bytes. Default is 2930.

mpegts_flags flags
Set mpegts flags. Accepts the following options:

resend_headers
Reemit PAT/PMT before writing the next packet.

latm
Use LATM packetization for AAC.

pat_pmt_at_frames
Reemit PAT and PMT at each video frame.

system_b
Conform to System B (DVB) instead of System A (ATSC).

initial_discontinuity
Mark the initial packet of each stream as discontinuity.

resend_headers integer
Reemit PAT/PMT before writing the next packet. This option is deprecated: use
mpegts_flags instead.

mpegts_copyts boolean
Preserve original timestamps, if value is set to 1. Default value is "-1", which
results in shifting timestamps so that they start from 0.

omit_video_pes_length boolean
Omit the PES packet length for video packets. Default is 1 (true).

pcr_period integer
Override the default PCR retransmission time in milliseconds. Ignored if variable
muxrate is selected. Default is 20.

pat_period double
Maximum time in seconds between PAT/PMT tables.

sdt_period double
Maximum time in seconds between SDT tables.

tables_version integer
Set PAT, PMT and SDT version (default 0, valid values are from 0 to 31, inclusively).
This option allows updating stream structure so that standard consumer may detect the
change. To do so, reopen output "AVFormatContext" (in case of API usage) or restart
ffmpeg instance, cyclically changing tables_version value:

ffmpeg -i source1.ts -codec copy -f mpegts -tables_version 0 udp://1.1.1.1:1111
ffmpeg -i source2.ts -codec copy -f mpegts -tables_version 1 udp://1.1.1.1:1111
...
ffmpeg -i source3.ts -codec copy -f mpegts -tables_version 31 udp://1.1.1.1:1111
ffmpeg -i source1.ts -codec copy -f mpegts -tables_version 0 udp://1.1.1.1:1111
ffmpeg -i source2.ts -codec copy -f mpegts -tables_version 1 udp://1.1.1.1:1111
...

Example

ffmpeg -i file.mpg -c copy \
-mpegts_original_network_id 0x1122 \
-mpegts_transport_stream_id 0x3344 \
-mpegts_service_id 0x5566 \
-mpegts_pmt_start_pid 0x1500 \
-mpegts_start_pid 0x150 \
-metadata service_provider="Some provider" \
-metadata service_name="Some Channel" \
out.ts

mxf, mxf_d10
MXF muxer.

Options

The muxer options are:

store_user_comments bool
Set if user comments should be stored if available or never. IRT D-10 does not allow
user comments. The default is thus to write them for mxf but not for mxf_d10

null
Null muxer.

This muxer does not generate any output file, it is mainly useful for testing or
benchmarking purposes.

For example to benchmark decoding with ffmpeg you can use the command:

ffmpeg -benchmark -i INPUT -f null out.null

Note that the above command does not read or write the out.null file, but specifying the
output file is required by the ffmpeg syntax.

Alternatively you can write the command as:

ffmpeg -benchmark -i INPUT -f null -

nut
-syncpoints flags
Change the syncpoint usage in nut:

default use the normal low-overhead seeking aids.
none do not use the syncpoints at all, reducing the overhead but making the stream
non-seekable;
Use of this option is not recommended, as the resulting files are very damage
sensitive and seeking is not possible. Also in general the overhead from
syncpoints is negligible. Note, -C<write_index> 0 can be used to disable
all growing data tables, allowing to mux endless streams with limited memory
and without these disadvantages.

timestamped extend the syncpoint with a wallclock field.

The none and timestamped flags are experimental.

-write_index bool
Write index at the end, the default is to write an index.

ffmpeg -i INPUT -f_strict experimental -syncpoints none - | processor

ogg
Ogg container muxer.

-page_duration duration
Preferred page duration, in microseconds. The muxer will attempt to create pages that
are approximately duration microseconds long. This allows the user to compromise
between seek granularity and container overhead. The default is 1 second. A value of 0
will fill all segments, making pages as large as possible. A value of 1 will
effectively use 1 packet-per-page in most situations, giving a small seek granularity
at the cost of additional container overhead.

-serial_offset value
Serial value from which to set the streams serial number. Setting it to different and
sufficiently large values ensures that the produced ogg files can be safely chained.

segment, stream_segment, ssegment
Basic stream segmenter.

This muxer outputs streams to a number of separate files of nearly fixed duration. Output
filename pattern can be set in a fashion similar to image2, or by using a "strftime"
template if the strftime option is enabled.

"stream_segment" is a variant of the muxer used to write to streaming output formats, i.e.
which do not require global headers, and is recommended for outputting e.g. to MPEG
transport stream segments. "ssegment" is a shorter alias for "stream_segment".

Every segment starts with a keyframe of the selected reference stream, which is set
through the reference_stream option.

Note that if you want accurate splitting for a video file, you need to make the input key
frames correspond to the exact splitting times expected by the segmenter, or the segment
muxer will start the new segment with the key frame found next after the specified start
time.

The segment muxer works best with a single constant frame rate video.

Optionally it can generate a list of the created segments, by setting the option
segment_list. The list type is specified by the segment_list_type option. The entry
filenames in the segment list are set by default to the basename of the corresponding
segment files.

See also the hls muxer, which provides a more specific implementation for HLS
segmentation.

Options

The segment muxer supports the following options:

increment_tc 1|0
if set to 1, increment timecode between each segment If this is selected, the input
need to have a timecode in the first video stream. Default value is 0.

reference_stream specifier
Set the reference stream, as specified by the string specifier. If specifier is set
to "auto", the reference is chosen automatically. Otherwise it must be a stream
specifier (see the ``Stream specifiers'' chapter in the ffmpeg manual) which specifies
the reference stream. The default value is "auto".

segment_format format
Override the inner container format, by default it is guessed by the filename
extension.

segment_format_options options_list
Set output format options using a :-separated list of key=value parameters. Values
containing the ":" special character must be escaped.

segment_list name
Generate also a listfile named name. If not specified no listfile is generated.

segment_list_flags flags
Set flags affecting the segment list generation.

It currently supports the following flags:

cache
Allow caching (only affects M3U8 list files).

live
Allow live-friendly file generation.

segment_list_size size
Update the list file so that it contains at most size segments. If 0 the list file
will contain all the segments. Default value is 0.

segment_list_entry_prefix prefix
Prepend prefix to each entry. Useful to generate absolute paths. By default no prefix
is applied.

segment_list_type type
Select the listing format.

The following values are recognized:

flat
Generate a flat list for the created segments, one segment per line.

csv, ext
Generate a list for the created segments, one segment per line, each line matching
the format (comma-separated values):

<segment_filename>,<segment_start_time>,<segment_end_time>

segment_filename is the name of the output file generated by the muxer according
to the provided pattern. CSV escaping (according to RFC4180) is applied if
required.

segment_start_time and segment_end_time specify the segment start and end time
expressed in seconds.

A list file with the suffix ".csv" or ".ext" will auto-select this format.

ext is deprecated in favor or csv.

ffconcat
Generate an ffconcat file for the created segments. The resulting file can be read
using the FFmpeg concat demuxer.

A list file with the suffix ".ffcat" or ".ffconcat" will auto-select this format.

m3u8
Generate an extended M3U8 file, version 3, compliant with
<http://tools.ietf.org/id/draft-pantos-http-live-streaming>.

A list file with the suffix ".m3u8" will auto-select this format.

If not specified the type is guessed from the list file name suffix.

segment_time time
Set segment duration to time, the value must be a duration specification. Default
value is "2". See also the segment_times option.

Note that splitting may not be accurate, unless you force the reference stream key-
frames at the given time. See the introductory notice and the examples below.

segment_atclocktime 1|0
If set to "1" split at regular clock time intervals starting from 00:00 o'clock. The
time value specified in segment_time is used for setting the length of the splitting
interval.

For example with segment_time set to "900" this makes it possible to create files at
12:00 o'clock, 12:15, 12:30, etc.

Default value is "0".

segment_clocktime_offset duration
Delay the segment splitting times with the specified duration when using
segment_atclocktime.

For example with segment_time set to "900" and segment_clocktime_offset set to "300"
this makes it possible to create files at 12:05, 12:20, 12:35, etc.

Default value is "0".

segment_clocktime_wrap_duration duration
Force the segmenter to only start a new segment if a packet reaches the muxer within
the specified duration after the segmenting clock time. This way you can make the
segmenter more resilient to backward local time jumps, such as leap seconds or
transition to standard time from daylight savings time.

Default is the maximum possible duration which means starting a new segment regardless
of the elapsed time since the last clock time.

segment_time_delta delta
Specify the accuracy time when selecting the start time for a segment, expressed as a
duration specification. Default value is "0".

When delta is specified a key-frame will start a new segment if its PTS satisfies the
relation:

PTS >= start_time - time_delta

This option is useful when splitting video content, which is always split at GOP
boundaries, in case a key frame is found just before the specified split time.

In particular may be used in combination with the ffmpeg option force_key_frames. The
key frame times specified by force_key_frames may not be set accurately because of
rounding issues, with the consequence that a key frame time may result set just before
the specified time. For constant frame rate videos a value of 1/(2*frame_rate) should
address the worst case mismatch between the specified time and the time set by
force_key_frames.

segment_times times
Specify a list of split points. times contains a list of comma separated duration
specifications, in increasing order. See also the segment_time option.

segment_frames frames
Specify a list of split video frame numbers. frames contains a list of comma separated
integer numbers, in increasing order.

This option specifies to start a new segment whenever a reference stream key frame is
found and the sequential number (starting from 0) of the frame is greater or equal to
the next value in the list.

segment_wrap limit
Wrap around segment index once it reaches limit.

segment_start_number number
Set the sequence number of the first segment. Defaults to 0.

strftime 1|0
Use the "strftime" function to define the name of the new segments to write. If this
is selected, the output segment name must contain a "strftime" function template.
Default value is 0.

break_non_keyframes 1|0
If enabled, allow segments to start on frames other than keyframes. This improves
behavior on some players when the time between keyframes is inconsistent, but may make
things worse on others, and can cause some oddities during seeking. Defaults to 0.

reset_timestamps 1|0
Reset timestamps at the beginning of each segment, so that each segment will start
with near-zero timestamps. It is meant to ease the playback of the generated segments.
May not work with some combinations of muxers/codecs. It is set to 0 by default.

initial_offset offset
Specify timestamp offset to apply to the output packet timestamps. The argument must
be a time duration specification, and defaults to 0.

write_empty_segments 1|0
If enabled, write an empty segment if there are no packets during the period a segment
would usually span. Otherwise, the segment will be filled with the next packet
written. Defaults to 0.

Examples

• Remux the content of file in.mkv to a list of segments out-000.nut, out-001.nut, etc.,
and write the list of generated segments to out.list:

ffmpeg -i in.mkv -codec copy -map 0 -f segment -segment_list out.list out%03d.nut

• Segment input and set output format options for the output segments:

ffmpeg -i in.mkv -f segment -segment_time 10 -segment_format_options movflags=+faststart out%03d.mp4

• Segment the input file according to the split points specified by the segment_times
option:

ffmpeg -i in.mkv -codec copy -map 0 -f segment -segment_list out.csv -segment_times 1,2,3,5,8,13,21 out%03d.nut

• Use the ffmpeg force_key_frames option to force key frames in the input at the
specified location, together with the segment option segment_time_delta to account for
possible roundings operated when setting key frame times.

ffmpeg -i in.mkv -force_key_frames 1,2,3,5,8,13,21 -codec:v mpeg4 -codec:a pcm_s16le -map 0 \
-f segment -segment_list out.csv -segment_times 1,2,3,5,8,13,21 -segment_time_delta 0.05 out%03d.nut

In order to force key frames on the input file, transcoding is required.

• Segment the input file by splitting the input file according to the frame numbers
sequence specified with the segment_frames option:

ffmpeg -i in.mkv -codec copy -map 0 -f segment -segment_list out.csv -segment_frames 100,200,300,500,800 out%03d.nut

• Convert the in.mkv to TS segments using the "libx264" and "aac" encoders:

ffmpeg -i in.mkv -map 0 -codec:v libx264 -codec:a aac -f ssegment -segment_list out.list out%03d.ts

• Segment the input file, and create an M3U8 live playlist (can be used as live HLS
source):

ffmpeg -re -i in.mkv -codec copy -map 0 -f segment -segment_list playlist.m3u8 \
-segment_list_flags +live -segment_time 10 out%03d.mkv

smoothstreaming
Smooth Streaming muxer generates a set of files (Manifest, chunks) suitable for serving
with conventional web server.

window_size
Specify the number of fragments kept in the manifest. Default 0 (keep all).

extra_window_size
Specify the number of fragments kept outside of the manifest before removing from
disk. Default 5.

lookahead_count
Specify the number of lookahead fragments. Default 2.

min_frag_duration
Specify the minimum fragment duration (in microseconds). Default 5000000.

remove_at_exit
Specify whether to remove all fragments when finished. Default 0 (do not remove).

fifo
The fifo pseudo-muxer allows the separation of encoding and muxing by using first-in-
first-out queue and running the actual muxer in a separate thread. This is especially
useful in combination with the tee muxer and can be used to send data to several
destinations with different reliability/writing speed/latency.

API users should be aware that callback functions (interrupt_callback, io_open and
io_close) used within its AVFormatContext must be thread-safe.

The behavior of the fifo muxer if the queue fills up or if the output fails is selectable,

• output can be transparently restarted with configurable delay between retries based on
real time or time of the processed stream.

• encoding can be blocked during temporary failure, or continue transparently dropping
packets in case fifo queue fills up.

fifo_format
Specify the format name. Useful if it cannot be guessed from the output name suffix.

queue_size
Specify size of the queue (number of packets). Default value is 60.

format_opts
Specify format options for the underlying muxer. Muxer options can be specified as a
list of key=value pairs separated by ':'.

drop_pkts_on_overflow bool
If set to 1 (true), in case the fifo queue fills up, packets will be dropped rather
than blocking the encoder. This makes it possible to continue streaming without
delaying the input, at the cost of omitting part of the stream. By default this option
is set to 0 (false), so in such cases the encoder will be blocked until the muxer
processes some of the packets and none of them is lost.

attempt_recovery bool
If failure occurs, attempt to recover the output. This is especially useful when used
with network output, since it makes it possible to restart streaming transparently.
By default this option is set to 0 (false).

max_recovery_attempts
Sets maximum number of successive unsuccessful recovery attempts after which the
output fails permanently. By default this option is set to 0 (unlimited).

recovery_wait_time duration
Waiting time before the next recovery attempt after previous unsuccessful recovery
attempt. Default value is 5 seconds.

recovery_wait_streamtime bool
If set to 0 (false), the real time is used when waiting for the recovery attempt (i.e.
the recovery will be attempted after at least recovery_wait_time seconds). If set to
1 (true), the time of the processed stream is taken into account instead (i.e. the
recovery will be attempted after at least recovery_wait_time seconds of the stream is
omitted). By default, this option is set to 0 (false).

recover_any_error bool
If set to 1 (true), recovery will be attempted regardless of type of the error causing
the failure. By default this option is set to 0 (false) and in case of certain
(usually permanent) errors the recovery is not attempted even when attempt_recovery is
set to 1.

restart_with_keyframe bool
Specify whether to wait for the keyframe after recovering from queue overflow or
failure. This option is set to 0 (false) by default.

Examples

• Stream something to rtmp server, continue processing the stream at real-time rate even
in case of temporary failure (network outage) and attempt to recover streaming every
second indefinitely.

ffmpeg -re -i ... -c:v libx264 -c:a aac -f fifo -fifo_format flv -map 0:v -map 0:a
-drop_pkts_on_overflow 1 -attempt_recovery 1 -recovery_wait_time 1 rtmp://example.com/live/stream_name

tee
The tee muxer can be used to write the same data to several files or any other kind of
muxer. It can be used, for example, to both stream a video to the network and save it to
disk at the same time.

It is different from specifying several outputs to the ffmpeg command-line tool because
the audio and video data will be encoded only once with the tee muxer; encoding can be a
very expensive process. It is not useful when using the libavformat API directly because
it is then possible to feed the same packets to several muxers directly.

use_fifo bool
If set to 1, slave outputs will be processed in separate thread using fifo muxer. This
allows to compensate for different speed/latency/reliability of outputs and setup
transparent recovery. By default this feature is turned off.

fifo_options
Options to pass to fifo pseudo-muxer instances. See fifo.

The slave outputs are specified in the file name given to the muxer, separated by '|'. If
any of the slave name contains the '|' separator, leading or trailing spaces or any
special character, it must be escaped (see the "Quoting and escaping" section in the
ffmpeg-utils(1) manual).

Muxer options can be specified for each slave by prepending them as a list of key=value
pairs separated by ':', between square brackets. If the options values contain a special
character or the ':' separator, they must be escaped; note that this is a second level
escaping.

The following special options are also recognized:

f Specify the format name. Useful if it cannot be guessed from the output name suffix.

bsfs[/spec]
Specify a list of bitstream filters to apply to the specified output.

use_fifo bool
This allows to override tee muxer use_fifo option for individual slave muxer.

fifo_options
This allows to override tee muxer fifo_options for individual slave muxer. See fifo.

It is possible to specify to which streams a given bitstream filter applies, by
appending a stream specifier to the option separated by "/". spec must be a stream
specifier (see Format stream specifiers). If the stream specifier is not specified,
the bitstream filters will be applied to all streams in the output.

Several bitstream filters can be specified, separated by ",".

select
Select the streams that should be mapped to the slave output, specified by a stream
specifier. If not specified, this defaults to all the input streams. You may use
multiple stream specifiers separated by commas (",") e.g.: "a:0,v"

onfail
Specify behaviour on output failure. This can be set to either "abort" (which is
default) or "ignore". "abort" will cause whole process to fail in case of failure on
this slave output. "ignore" will ignore failure on this output, so other outputs will
continue without being affected.

Examples

• Encode something and both archive it in a WebM file and stream it as MPEG-TS over UDP
(the streams need to be explicitly mapped):

ffmpeg -i ... -c:v libx264 -c:a mp2 -f tee -map 0:v -map 0:a
"archive-20121107.mkv|[f=mpegts]udp://10.0.1.255:1234/"

• As above, but continue streaming even if output to local file fails (for example local
drive fills up):

ffmpeg -i ... -c:v libx264 -c:a mp2 -f tee -map 0:v -map 0:a
"[onfail=ignore]archive-20121107.mkv|[f=mpegts]udp://10.0.1.255:1234/"

• Use ffmpeg to encode the input, and send the output to three different destinations.
The "dump_extra" bitstream filter is used to add extradata information to all the
output video keyframes packets, as requested by the MPEG-TS format. The select option
is applied to out.aac in order to make it contain only audio packets.

ffmpeg -i ... -map 0 -flags +global_header -c:v libx264 -c:a aac
-f tee "[bsfs/v=dump_extra]out.ts|[movflags=+faststart]out.mp4|[select=a]out.aac"

• As below, but select only stream "a:1" for the audio output. Note that a second level
escaping must be performed, as ":" is a special character used to separate options.

ffmpeg -i ... -map 0 -flags +global_header -c:v libx264 -c:a aac
-f tee "[bsfs/v=dump_extra]out.ts|[movflags=+faststart]out.mp4|[select=\'a:1\']out.aac"

Note: some codecs may need different options depending on the output format; the auto-
detection of this can not work with the tee muxer. The main example is the global_header
flag.

webm_dash_manifest
WebM DASH Manifest muxer.

This muxer implements the WebM DASH Manifest specification to generate the DASH manifest
XML. It also supports manifest generation for DASH live streams.

For more information see:

• WebM DASH Specification:
<https://sites.google.com/a/webmproject.org/wiki/adaptive-streaming/webm-dash-specification>

• ISO DASH Specification:
<http://standards.iso.org/ittf/PubliclyAvailableStandards/c065274_ISO_IEC_23009-1_2014.zip>

Options

This muxer supports the following options:

adaptation_sets
This option has the following syntax: "id=x,streams=a,b,c id=y,streams=d,e" where x
and y are the unique identifiers of the adaptation sets and a,b,c,d and e are the
indices of the corresponding audio and video streams. Any number of adaptation sets
can be added using this option.

live
Set this to 1 to create a live stream DASH Manifest. Default: 0.

chunk_start_index
Start index of the first chunk. This will go in the startNumber attribute of the
SegmentTemplate element in the manifest. Default: 0.

chunk_duration_ms
Duration of each chunk in milliseconds. This will go in the duration attribute of the
SegmentTemplate element in the manifest. Default: 1000.

utc_timing_url
URL of the page that will return the UTC timestamp in ISO format. This will go in the
value attribute of the UTCTiming element in the manifest. Default: None.

time_shift_buffer_depth
Smallest time (in seconds) shifting buffer for which any Representation is guaranteed
to be available. This will go in the timeShiftBufferDepth attribute of the MPD
element. Default: 60.

minimum_update_period
Minimum update period (in seconds) of the manifest. This will go in the
minimumUpdatePeriod attribute of the MPD element. Default: 0.

Example

ffmpeg -f webm_dash_manifest -i video1.webm \
-f webm_dash_manifest -i video2.webm \
-f webm_dash_manifest -i audio1.webm \
-f webm_dash_manifest -i audio2.webm \
-map 0 -map 1 -map 2 -map 3 \
-c copy \
-f webm_dash_manifest \
-adaptation_sets "id=0,streams=0,1 id=1,streams=2,3" \
manifest.xml

webm_chunk
WebM Live Chunk Muxer.

This muxer writes out WebM headers and chunks as separate files which can be consumed by
clients that support WebM Live streams via DASH.

Options

This muxer supports the following options:

chunk_start_index
Index of the first chunk (defaults to 0).

header
Filename of the header where the initialization data will be written.

audio_chunk_duration
Duration of each audio chunk in milliseconds (defaults to 5000).

Example

ffmpeg -f v4l2 -i /dev/video0 \
-f alsa -i hw:0 \
-map 0:0 \
-c:v libvpx-vp9 \
-s 640x360 -keyint_min 30 -g 30 \
-f webm_chunk \
-header webm_live_video_360.hdr \
-chunk_start_index 1 \
webm_live_video_360_%d.chk \
-map 1:0 \
-c:a libvorbis \
-b:a 128k \
-f webm_chunk \
-header webm_live_audio_128.hdr \
-chunk_start_index 1 \
-audio_chunk_duration 1000 \
webm_live_audio_128_%d.chk

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

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.

                                                                                FFMPEG-FORMATS(1)

NAME

DESCRIPTION

FORMAT OPTIONS

DEMUXERS

MUXERS

METADATA

SEE ALSO

AUTHORS