Ubuntu Manpage: ffmpeg-formats

Provided by: ffmpeg_6.1.1-3ubuntu5_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.

max_probe_packets integer (input)
Set the maximum number of buffered packets when probing a codec. Default is 2500 packets.

packetsize integer (output)
Set packet size.

fflags flags
Set format flags. Some are implemented for a limited number of formats.

Possible values for input files:

discardcorrupt
Discard corrupted packets.

fastseek
Enable fast, but inaccurate seeks for some formats.

genpts
Generate missing PTS if DTS is present.

igndts
Ignore DTS if PTS is set. Inert when nofillin is set.

ignidx
Ignore index.

nobuffer
Reduce the latency introduced by buffering during initial input streams analysis.

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

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

sortdts
Try to interleave output packets by DTS. At present, available only for AVIs with an index.

Possible values for output files:

autobsf
Automatically apply bitstream filters as required by the output format. Enabled by default.

bitexact
Only write platform-, build- and time-independent data. This ensures that file and data
checksums are reproducible and match between platforms. Its primary use is for regression
testing.

flush_packets
Write out packets immediately.

shortest
Stop muxing at the end of the shortest stream. It may be needed to increase max_interleave_delta
to avoid flushing the longer streams before EOF.

seek2any integer (input)
Allow seeking to non-keyframes on demuxer level when supported if set to 1. Default is 0.

analyzeduration integer (input)
Specify how many microseconds are analyzed to probe the input. A higher value will enable detecting
more accurate information, but will increase latency. It defaults to 5,000,000 microseconds = 5
seconds.

cryptokey hexadecimal string (input)
Set decryption key.

indexmem integer (input)
Set max memory used for timestamp index (per stream).

rtbufsize integer (input)
Set max memory used for buffering real-time frames.

fdebug flags (input/output)
Print specific debug info.

Possible values:

ts
max_delay integer (input/output)
Set maximum muxing or demuxing delay in microseconds.

fpsprobesize integer (input)
Set number of frames used to probe fps.

audio_preload integer (output)
Set microseconds by which audio packets should be interleaved earlier.

chunk_duration integer (output)
Set microseconds for each chunk.

chunk_size integer (output)
Set size in bytes for each chunk.

err_detect, f_err_detect flags (input)
Set error detection flags. "f_err_detect" is deprecated and should be used only via the ffmpeg tool.

Possible values:

crccheck
Verify embedded CRCs.

bitstream
Detect bitstream specification deviations.

buffer
Detect improper bitstream length.

explode
Abort decoding on minor error detection.

careful
Consider things that violate the spec and have not been seen in the wild as errors.

compliant
Consider all spec non compliancies as errors.

aggressive
Consider things that a sane encoder should not do as an error.

max_interleave_delta integer (output)
Set maximum buffering duration for interleaving. The duration is expressed in microseconds, and
defaults to 10000000 (10 seconds).

To ensure all the streams are interleaved correctly, libavformat will wait until it has at least one
packet for each stream before actually writing any packets to the output file. When some streams are
"sparse" (i.e. there are large gaps between successive packets), this can result in excessive
buffering.

This field specifies the maximum difference between the timestamps of the first and the last packet
in the muxing queue, above which libavformat will output a packet regardless of whether it has queued
a packet for all the streams.

If set to 0, libavformat will continue buffering packets until it has a packet for each stream,
regardless of the maximum timestamp difference between the buffered packets.

use_wallclock_as_timestamps integer (input)
Use wallclock as timestamps if set to 1. Default is 0.

avoid_negative_ts integer (output)
Possible values:

make_non_negative
Shift timestamps to make them non-negative. Also note that this affects only leading negative
timestamps, and not non-monotonic negative timestamps.

make_zero
Shift timestamps so that the first timestamp is 0.

auto (default)
Enables shifting when required by the target format.

disabled
Disables shifting of timestamp.

When shifting is enabled, all output timestamps are shifted by the same amount. Audio, video, and
subtitles desynching and relative timestamp differences are preserved compared to how they would have
been without shifting.

skip_initial_bytes integer (input)
Set number of bytes to skip before reading header and frames if set to 1. Default is 0.

correct_ts_overflow integer (input)
Correct single timestamp overflows if set to 1. Default is 1.

flush_packets integer (output)
Flush the underlying I/O stream after each packet. Default is -1 (auto), which means that the
underlying protocol will decide, 1 enables it, and has the effect of reducing the latency, 0 disables
it and may increase IO throughput in some cases.

output_ts_offset offset (output)
Set the output time offset.

offset must be a time duration specification, see the Time duration section in the ffmpeg-utils(1)
manual.

The offset is added by the muxer to the output timestamps.

Specifying a positive offset means that the corresponding streams are delayed bt the time duration
specified in offset. Default value is 0 (meaning that no offset is applied).

format_whitelist list (input)
"," separated list of allowed demuxers. By default all are allowed.

dump_separator string (input)
Separator used to separate the fields printed on the command line about the Stream parameters. For
example, to separate the fields with newlines and indentation:

ffprobe -dump_separator "
" -i ~/videos/matrixbench_mpeg2.mpg

max_streams integer (input)
Specifies the maximum number of streams. This can be used to reject files that would require too many
resources due to a large number of streams.

skip_estimate_duration_from_pts bool (input)
Skip estimation of input duration when calculated using PTS. At present, applicable for MPEG-PS and
MPEG-TS.

strict, f_strict integer (input/output)
Specify how strictly to follow the standards. "f_strict" is deprecated and should be used only via
the ffmpeg tool.

Possible values:

very
strictly conform to an older more strict version of the spec or reference software

strict
strictly conform to all the things in the spec no matter what consequences

normal
unofficial
allow unofficial extensions

experimental
allow non standardized experimental things, experimental (unfinished/work in progress/not well
tested) decoders and encoders. Note: experimental decoders can pose a security risk, do not use
this for decoding untrusted input.

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

The exact semantics of stream specifiers is defined by the avformat_match_stream_specifier() function
declared in the libavformat/avformat.h header and documented in the Stream specifiers section in the
ffmpeg(1) manual.

DEMUXERS

Demuxers are configured elements in FFmpeg that can read the multimedia streams from a particular type of
file.

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

You can disable all the demuxers using the configure option "--disable-demuxers", and selectively enable
a single demuxer with the option "--enable-demuxer=DEMUXER", or disable it with the option
"--disable-demuxer=DEMUXER".

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

The description of some of the currently available demuxers follows.

aa
Audible Format 2, 3, and 4 demuxer.

This demuxer is used to demux Audible Format 2, 3, and 4 (.aa) files.

aac
Raw Audio Data Transport Stream AAC demuxer.

This demuxer is used to demux an ADTS input containing a single AAC stream alongwith any ID3v1/2 or APE
tags in it.

apng
Animated Portable Network Graphics demuxer.

This demuxer is used to demux APNG files. All headers, but the PNG signature, up to (but not including)
the first fcTL chunk are transmitted as extradata. Frames are then split as being all the chunks between
two fcTL ones, or between the last fcTL and IEND chunks.

-ignore_loop bool
Ignore the loop variable in the file if set. Default is enabled.

-max_fps int
Maximum framerate in frames per second. Default of 0 imposes no limit.

-default_fps int
Default framerate in frames per second when none is specified in the file (0 meaning as fast as
possible). Default is 15.

asf
Advanced Systems Format demuxer.

This demuxer is used to demux ASF files and MMS network streams.

-no_resync_search bool
Do not try to resynchronize by looking for a certain optional start code.

concat
Virtual concatenation script demuxer.

This demuxer reads a list of files and other directives from a text file and demuxes them one after the
other, as if all their packets had been muxed together.

The timestamps in the files are adjusted so that the first file starts at 0 and each next file starts
where the previous one finishes. Note that it is done globally and may cause gaps if all streams do not
have exactly the same length.

All files must have the same streams (same codecs, same time base, etc.).

The duration of each file is used to adjust the timestamps of the next file: if the duration is incorrect
(because it was computed using the bit-rate or because the file is truncated, for example), it can cause
artifacts. The "duration" directive can be used to override the duration stored in each file.

Syntax

The script is a text file in extended-ASCII, with one directive per line. Empty lines, leading spaces
and lines starting with '#' are ignored. The following directive is recognized:

"file path"
Path to a file to read; special characters and spaces must be escaped with backslash or single
quotes.

All subsequent file-related directives apply to that file.

"ffconcat version 1.0"
Identify the script type and version.

To make FFmpeg recognize the format automatically, this directive must appear exactly as is (no extra
space or byte-order-mark) on the very first line of the script.

"duration dur"
Duration of the file. This information can be specified from the file; specifying it here may be more
efficient or help if the information from the file is not available or accurate.

If the duration is set for all files, then it is possible to seek in the whole concatenated video.

"inpoint timestamp"
In point of the file. When the demuxer opens the file it instantly seeks to the specified timestamp.
Seeking is done so that all streams can be presented successfully at In point.

This directive works best with intra frame codecs, because for non-intra frame ones you will usually
get extra packets before the actual In point and the decoded content will most likely contain frames
before In point too.

For each file, packets before the file In point will have timestamps less than the calculated start
timestamp of the file (negative in case of the first file), and the duration of the files (if not
specified by the "duration" directive) will be reduced based on their specified In point.

Because of potential packets before the specified In point, packet timestamps may overlap between two
concatenated files.

"outpoint timestamp"
Out point of the file. When the demuxer reaches the specified decoding timestamp in any of the
streams, it handles it as an end of file condition and skips the current and all the remaining
packets from all streams.

Out point is exclusive, which means that the demuxer will not output packets with a decoding
timestamp greater or equal to Out point.

This directive works best with intra frame codecs and formats where all streams are tightly
interleaved. For non-intra frame codecs you will usually get additional packets with presentation
timestamp after Out point therefore the decoded content will most likely contain frames after Out
point too. If your streams are not tightly interleaved you may not get all the packets from all
streams before Out point and you may only will be able to decode the earliest stream until Out point.

The duration of the files (if not specified by the "duration" directive) will be reduced based on
their specified Out point.

"file_packet_metadata key=value"
Metadata of the packets of the file. The specified metadata will be set for each file packet. You can
specify this directive multiple times to add multiple metadata entries. This directive is
deprecated, use "file_packet_meta" instead.

"file_packet_meta key value"
Metadata of the packets of the file. The specified metadata will be set for each file packet. You can
specify this directive multiple times to add multiple metadata entries.

"option key value"
Option to access, open and probe the file. Can be present multiple times.

"stream"
Introduce a stream in the virtual file. All subsequent stream-related directives apply to the last
introduced stream. Some streams properties must be set in order to allow identifying the matching
streams in the subfiles. If no streams are defined in the script, the streams from the first file
are copied.

"exact_stream_id id"
Set the id of the stream. If this directive is given, the string with the corresponding id in the
subfiles will be used. This is especially useful for MPEG-PS (VOB) files, where the order of the
streams is not reliable.

"stream_meta key value"
Metadata for the stream. Can be present multiple times.

"stream_codec value"
Codec for the stream.

"stream_extradata hex_string"
Extradata for the string, encoded in hexadecimal.

"chapter id start end"
Add a chapter. id is an unique identifier, possibly small and consecutive.

Options

This demuxer accepts the following option:

safe
If set to 1, reject unsafe file paths and directives. A file path is considered safe if it does not
contain a protocol specification and is relative and all components only contain characters from the
portable character set (letters, digits, period, underscore and hyphen) and have no period at the
beginning of a component.

If set to 0, any file name is accepted.

The default is 1.

auto_convert
If set to 1, try to perform automatic conversions on packet data to make the streams concatenable.
The default is 1.

Currently, the only conversion is adding the h264_mp4toannexb bitstream filter to H.264 streams in
MP4 format. This is necessary in particular if there are resolution changes.

segment_time_metadata
If set to 1, every packet will contain the lavf.concat.start_time and the lavf.concat.duration packet
metadata values which are the start_time and the duration of the respective file segments in the
concatenated output expressed in microseconds. The duration metadata is only set if it is known based
on the concat file. The default is 0.

Examples

• Use absolute filenames and include some comments:

# my first filename
file /mnt/share/file-1.wav
# my second filename including whitespace
file '/mnt/share/file 2.wav'
# my third filename including whitespace plus single quote
file '/mnt/share/file 3'\''.wav'

• Allow for input format auto-probing, use safe filenames and set the duration of the first file:

ffconcat version 1.0

file file-1.wav
duration 20.0

file subdir/file-2.wav

dash
Dynamic Adaptive Streaming over HTTP demuxer.

This demuxer presents all AVStreams found in the manifest. By setting the discard flags on AVStreams the
caller can decide which streams to actually receive. Each stream mirrors the "id" and "bandwidth"
properties from the "<Representation>" as metadata keys named "id" and "variant_bitrate" respectively.

Options

This demuxer accepts the following option:

cenc_decryption_key
16-byte key, in hex, to decrypt files encrypted using ISO Common Encryption (CENC/AES-128 CTR;
ISO/IEC 23001-7).

ea
Electronic Arts Multimedia format demuxer.

This format is used by various Electronic Arts games.

Options

merge_alpha bool
Normally the VP6 alpha channel (if exists) is returned as a secondary video stream, by setting this
option you can make the demuxer return a single video stream which contains the alpha channel in
addition to the ordinary video.

imf
Interoperable Master Format demuxer.

This demuxer presents audio and video streams found in an IMF Composition, as specified in
<https://doi.org/10.5594/SMPTE.ST2067-2.2020>.

ffmpeg [-assetmaps <path of ASSETMAP1>,<path of ASSETMAP2>,...] -i <path of CPL> ...

If "-assetmaps" is not specified, the demuxer looks for a file called ASSETMAP.xml in the same directory
as the CPL.

flv, live_flv, kux
Adobe Flash Video Format demuxer.

This demuxer is used to demux FLV files and RTMP network streams. In case of live network streams, if you
force format, you may use live_flv option instead of flv to survive timestamp discontinuities. KUX is a
flv variant used on the Youku platform.

ffmpeg -f flv -i myfile.flv ...
ffmpeg -f live_flv -i rtmp://<any.server>/anything/key ....

-flv_metadata bool
Allocate the streams according to the onMetaData array content.

-flv_ignore_prevtag bool
Ignore the size of previous tag value.

-flv_full_metadata bool
Output all context of the onMetadata.

gif
Animated GIF demuxer.

It accepts the following options:

min_delay
Set the minimum valid delay between frames in hundredths of seconds. Range is 0 to 6000. Default
value is 2.

max_gif_delay
Set the maximum valid delay between frames in hundredth of seconds. Range is 0 to 65535. Default
value is 65535 (nearly eleven minutes), the maximum value allowed by the specification.

default_delay
Set the default delay between frames in hundredths of seconds. Range is 0 to 6000. Default value is
10.

ignore_loop
GIF files can contain information to loop a certain number of times (or infinitely). If ignore_loop
is set to 1, then the loop setting from the input will be ignored and looping will not occur. If set
to 0, then looping will occur and will cycle the number of times according to the GIF. Default value
is 1.

For example, with the overlay filter, place an infinitely looping GIF over another video:

ffmpeg -i input.mp4 -ignore_loop 0 -i input.gif -filter_complex overlay=shortest=1 out.mkv

Note that in the above example the shortest option for overlay filter is used to end the output video at
the length of the shortest input file, which in this case is input.mp4 as the GIF in this example loops
infinitely.

hls
HLS demuxer

Apple HTTP Live Streaming demuxer.

This demuxer presents all AVStreams from all variant streams. The id field is set to the bitrate variant
index number. By setting the discard flags on AVStreams (by pressing 'a' or 'v' in ffplay), the caller
can decide which variant streams to actually receive. The total bitrate of the variant that the stream
belongs to is available in a metadata key named "variant_bitrate".

It accepts the following options:

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

prefer_x_start
prefer to use #EXT-X-START if it's in playlist instead of live_start_index.

allowed_extensions
',' separated list of file extensions that hls is allowed to access.

max_reload
Maximum number of times a insufficient list is attempted to be reloaded. Default value is 1000.

m3u8_hold_counters
The maximum number of times to load m3u8 when it refreshes without new segments. Default value is
1000.

http_persistent
Use persistent HTTP connections. Applicable only for HTTP streams. Enabled by default.

http_multiple
Use multiple HTTP connections for downloading HTTP segments. Enabled by default for HTTP/1.1
servers.

http_seekable
Use HTTP partial requests for downloading HTTP segments. 0 = disable, 1 = enable, -1 = auto, Default
is auto.

seg_format_options
Set options for the demuxer of media segments using a list of key=value pairs separated by ":".

seg_max_retry
Maximum number of times to reload a segment on error, useful when segment skip on network error is
not desired. Default value is 0.

image2
Image file demuxer.

This demuxer reads from a list of image files specified by a pattern. The syntax and meaning of the
pattern is specified by the option pattern_type.

The pattern may contain a suffix which is used to automatically determine the format of the images
contained in the files.

The size, the pixel format, and the format of each image must be the same for all the files in the
sequence.

This demuxer accepts the following options:

framerate
Set the frame rate for the video stream. It defaults to 25.

loop
If set to 1, loop over the input. Default value is 0.

pattern_type
Select the pattern type used to interpret the provided filename.

pattern_type accepts one of the following values.

none
Disable pattern matching, therefore the video will only contain the specified image. You should
use this option if you do not want to create sequences from multiple images and your filenames
may contain special pattern characters.

sequence
Select a sequence pattern type, used to specify a sequence of files indexed by sequential
numbers.

A sequence pattern may contain the string "%d" or "%0Nd", which specifies the position of the
characters representing a sequential number in each filename matched by the pattern. If the form
"%d0Nd" is used, the string representing the number in each filename is 0-padded and N is the
total number of 0-padded digits representing the number. The literal character '%' can be
specified in the pattern with the string "%%".

If the sequence pattern contains "%d" or "%0Nd", the first filename of the file list specified by
the pattern must contain a number inclusively contained between start_number and
start_number+start_number_range-1, and all the following numbers must be sequential.

For example the pattern "img-%03d.bmp" will match a sequence of filenames of the form
img-001.bmp, img-002.bmp, ..., img-010.bmp, etc.; the pattern "i%%m%%g-%d.jpg" will match a
sequence of filenames of the form i%m%g-1.jpg, i%m%g-2.jpg, ..., i%m%g-10.jpg, etc.

Note that the pattern must not necessarily contain "%d" or "%0Nd", for example to convert a
single image file img.jpeg you can employ the command:

ffmpeg -i img.jpeg img.png

glob
Select a glob wildcard pattern type.

The pattern is interpreted like a glob() pattern. This is only selectable if libavformat was
compiled with globbing support.

glob_sequence (deprecated, will be removed)
Select a mixed glob wildcard/sequence pattern.

If your version of libavformat was compiled with globbing support, and the provided pattern
contains at least one glob meta character among "%*?[]{}" that is preceded by an unescaped "%",
the pattern is interpreted like a glob() pattern, otherwise it is interpreted like a sequence
pattern.

All glob special characters "%*?[]{}" must be prefixed with "%". To escape a literal "%" you
shall use "%%".

For example the pattern "foo-%*.jpeg" will match all the filenames prefixed by "foo-" and
terminating with ".jpeg", and "foo-%?%?%?.jpeg" will match all the filenames prefixed with
"foo-", followed by a sequence of three characters, and terminating with ".jpeg".

This pattern type is deprecated in favor of glob and sequence.

Default value is glob_sequence.

pixel_format
Set the pixel format of the images to read. If not specified the pixel format is guessed from the
first image file in the sequence.

start_number
Set the index of the file matched by the image file pattern to start to read from. Default value is
0.

start_number_range
Set the index interval range to check when looking for the first image file in the sequence, starting
from start_number. Default value is 5.

ts_from_file
If set to 1, will set frame timestamp to modification time of image file. Note that monotonity of
timestamps is not provided: images go in the same order as without this option. Default value is 0.
If set to 2, will set frame timestamp to the modification time of the image file in nanosecond
precision.

video_size
Set the video size of the images to read. If not specified the video size is guessed from the first
image file in the sequence.

export_path_metadata
If set to 1, will add two extra fields to the metadata found in input, making them also available for
other filters (see drawtext filter for examples). Default value is 0. The extra fields are described
below:

lavf.image2dec.source_path
Corresponds to the full path to the input file being read.

lavf.image2dec.source_basename
Corresponds to the name of the file being read.

Examples

• Use ffmpeg for creating a video from the images in the file sequence img-001.jpeg, img-002.jpeg, ...,
assuming an input frame rate of 10 frames per second:

ffmpeg -framerate 10 -i 'img-%03d.jpeg' out.mkv

• As above, but start by reading from a file with index 100 in the sequence:

ffmpeg -framerate 10 -start_number 100 -i 'img-%03d.jpeg' out.mkv

• Read images matching the "*.png" glob pattern , that is all the files terminating with the ".png"
suffix:

ffmpeg -framerate 10 -pattern_type glob -i "*.png" out.mkv

libgme
The Game Music Emu library is a collection of video game music file emulators.

See <https://bitbucket.org/mpyne/game-music-emu/overview> for more information.

It accepts the following options:

track_index
Set the index of which track to demux. The demuxer can only export one track. Track indexes start at
0. Default is to pick the first track. Number of tracks is exported as tracks metadata entry.

sample_rate
Set the sampling rate of the exported track. Range is 1000 to 999999. Default is 44100.

max_size (bytes)
The demuxer buffers the entire file into memory. Adjust this value to set the maximum buffer size,
which in turn, acts as a ceiling for the size of files that can be read. Default is 50 MiB.

libmodplug
ModPlug based module demuxer

See <https://github.com/Konstanty/libmodplug>

It will export one 2-channel 16-bit 44.1 kHz audio stream. Optionally, a "pal8" 16-color video stream
can be exported with or without printed metadata.

It accepts the following options:

noise_reduction
Apply a simple low-pass filter. Can be 1 (on) or 0 (off). Default is 0.

reverb_depth
Set amount of reverb. Range 0-100. Default is 0.

reverb_delay
Set delay in ms, clamped to 40-250 ms. Default is 0.

bass_amount
Apply bass expansion a.k.a. XBass or megabass. Range is 0 (quiet) to 100 (loud). Default is 0.

bass_range
Set cutoff i.e. upper-bound for bass frequencies. Range is 10-100 Hz. Default is 0.

surround_depth
Apply a Dolby Pro-Logic surround effect. Range is 0 (quiet) to 100 (heavy). Default is 0.

surround_delay
Set surround delay in ms, clamped to 5-40 ms. Default is 0.

max_size
The demuxer buffers the entire file into memory. Adjust this value to set the maximum buffer size,
which in turn, acts as a ceiling for the size of files that can be read. Range is 0 to 100 MiB. 0
removes buffer size limit (not recommended). Default is 5 MiB.

video_stream_expr
String which is evaluated using the eval API to assign colors to the generated video stream.
Variables which can be used are "x", "y", "w", "h", "t", "speed", "tempo", "order", "pattern" and
"row".

video_stream
Generate video stream. Can be 1 (on) or 0 (off). Default is 0.

video_stream_w
Set video frame width in 'chars' where one char indicates 8 pixels. Range is 20-512. Default is 30.

video_stream_h
Set video frame height in 'chars' where one char indicates 8 pixels. Range is 20-512. Default is 30.

video_stream_ptxt
Print metadata on video stream. Includes "speed", "tempo", "order", "pattern", "row" and "ts" (time
in ms). Can be 1 (on) or 0 (off). Default is 1.

libopenmpt
libopenmpt based module demuxer

See <https://lib.openmpt.org/libopenmpt/> for more information.

Some files have multiple subsongs (tracks) this can be set with the subsong option.

It accepts the following options:

subsong
Set the subsong index. This can be either 'all', 'auto', or the index of the subsong. Subsong
indexes start at 0. The default is 'auto'.

The default value is to let libopenmpt choose.

layout
Set the channel layout. Valid values are 1, 2, and 4 channel layouts. The default value is STEREO.

sample_rate
Set the sample rate for libopenmpt to output. Range is from 1000 to INT_MAX. The value default is
48000.

mov/mp4/3gp
Demuxer for Quicktime File Format & ISO/IEC Base Media File Format (ISO/IEC 14496-12 or MPEG-4 Part 12,
ISO/IEC 15444-12 or JPEG 2000 Part 12).

Registered extensions: mov, mp4, m4a, 3gp, 3g2, mj2, psp, m4b, ism, ismv, isma, f4v

Options

This demuxer accepts the following options:

enable_drefs
Enable loading of external tracks, disabled by default. Enabling this can theoretically leak
information in some use cases.

use_absolute_path
Allows loading of external tracks via absolute paths, disabled by default. Enabling this poses a
security risk. It should only be enabled if the source is known to be non-malicious.

seek_streams_individually
When seeking, identify the closest point in each stream individually and demux packets in that stream
from identified point. This can lead to a different sequence of packets compared to demuxing linearly
from the beginning. Default is true.

ignore_editlist
Ignore any edit list atoms. The demuxer, by default, modifies the stream index to reflect the
timeline described by the edit list. Default is false.

advanced_editlist
Modify the stream index to reflect the timeline described by the edit list. "ignore_editlist" must be
set to false for this option to be effective. If both "ignore_editlist" and this option are set to
false, then only the start of the stream index is modified to reflect initial dwell time or starting
timestamp described by the edit list. Default is true.

ignore_chapters
Don't parse chapters. This includes GoPro 'HiLight' tags/moments. Note that chapters are only parsed
when input is seekable. Default is false.

use_mfra_for
For seekable fragmented input, set fragment's starting timestamp from media fragment random access
box, if present.

Following options are available:

auto
Auto-detect whether to set mfra timestamps as PTS or DTS (default)

dts Set mfra timestamps as DTS

pts Set mfra timestamps as PTS

0 Don't use mfra box to set timestamps

use_tfdt
For fragmented input, set fragment's starting timestamp to "baseMediaDecodeTime" from the "tfdt" box.
Default is enabled, which will prefer to use the "tfdt" box to set DTS. Disable to use the
"earliest_presentation_time" from the "sidx" box. In either case, the timestamp from the "mfra" box
will be used if it's available and "use_mfra_for" is set to pts or dts.

export_all
Export unrecognized boxes within the udta box as metadata entries. The first four characters of the
box type are set as the key. Default is false.

export_xmp
Export entire contents of XMP_ box and uuid box as a string with key "xmp". Note that if "export_all"
is set and this option isn't, the contents of XMP_ box are still exported but with key "XMP_".
Default is false.

activation_bytes
4-byte key required to decrypt Audible AAX and AAX+ files. See Audible AAX subsection below.

audible_fixed_key
Fixed key used for handling Audible AAX/AAX+ files. It has been pre-set so should not be necessary to
specify.

decryption_key
16-byte key, in hex, to decrypt files encrypted using ISO Common Encryption (CENC/AES-128 CTR;
ISO/IEC 23001-7).

max_stts_delta
Very high sample deltas written in a trak's stts box may occasionally be intended but usually they
are written in error or used to store a negative value for dts correction when treated as signed
32-bit integers. This option lets the user set an upper limit, beyond which the delta is clamped to
1. Values greater than the limit if negative when cast to int32 are used to adjust onward dts.

Unit is the track time scale. Range is 0 to UINT_MAX. Default is "UINT_MAX - 48000*10" which allows
upto a 10 second dts correction for 48 kHz audio streams while accommodating 99.9% of "uint32" range.

interleaved_read
Interleave packets from multiple tracks at demuxer level. For badly interleaved files, this prevents
playback issues caused by large gaps between packets in different tracks, as MOV/MP4 do not have
packet placement requirements. However, this can cause excessive seeking on very badly interleaved
files, due to seeking between tracks, so disabling it may prevent I/O issues, at the expense of
playback.

Audible AAX

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

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

mpegts
MPEG-2 transport stream demuxer.

This demuxer accepts the following options:

resync_size
Set size limit for looking up a new synchronization. Default value is 65536.

skip_unknown_pmt
Skip PMTs for programs not defined in the PAT. Default value is 0.

fix_teletext_pts
Override teletext packet PTS and DTS values with the timestamps calculated from the PCR of the first
program which the teletext stream is part of and is not discarded. Default value is 1, set this
option to 0 if you want your teletext packet PTS and DTS values untouched.

ts_packetsize
Output option carrying the raw packet size in bytes. Show the detected raw packet size, cannot be
set by the user.

scan_all_pmts
Scan and combine all PMTs. The value is an integer with value from -1 to 1 (-1 means automatic
setting, 1 means enabled, 0 means disabled). Default value is -1.

merge_pmt_versions
Re-use existing streams when a PMT's version is updated and elementary streams move to different
PIDs. Default value is 0.

max_packet_size
Set maximum size, in bytes, of packet emitted by the demuxer. Payloads above this size are split
across multiple packets. Range is 1 to INT_MAX/2. Default is 204800 bytes.

mpjpeg
MJPEG encapsulated in multi-part MIME demuxer.

This demuxer allows reading of MJPEG, where each frame is represented as a part of
multipart/x-mixed-replace stream.

strict_mime_boundary
Default implementation applies a relaxed standard to multi-part MIME boundary detection, to prevent
regression with numerous existing endpoints not generating a proper MIME MJPEG stream. Turning this
option on by setting it to 1 will result in a stricter check of the boundary value.

rawvideo
Raw video demuxer.

This demuxer allows one to read raw video data. Since there is no header specifying the assumed video
parameters, the user must specify them in order to be able to decode the data correctly.

This demuxer accepts the following options:

framerate
Set input video frame rate. Default value is 25.

pixel_format
Set the input video pixel format. Default value is "yuv420p".

video_size
Set the input video size. This value must be specified explicitly.

For example to read a rawvideo file input.raw with ffplay, assuming a pixel format of "rgb24", a video
size of "320x240", and a frame rate of 10 images per second, use the command:

ffplay -f rawvideo -pixel_format rgb24 -video_size 320x240 -framerate 10 input.raw

sbg
SBaGen script demuxer.

This demuxer reads the script language used by SBaGen <http://uazu.net/sbagen/> to generate binaural
beats sessions. A SBG script looks like that:

-SE
a: 300-2.5/3 440+4.5/0
b: 300-2.5/0 440+4.5/3
off: -
NOW == a
+0:07:00 == b
+0:14:00 == a
+0:21:00 == b
+0:30:00 off

A SBG script can mix absolute and relative timestamps. If the script uses either only absolute timestamps
(including the script start time) or only relative ones, then its layout is fixed, and the conversion is
straightforward. On the other hand, if the script mixes both kind of timestamps, then the NOW reference
for relative timestamps will be taken from the current time of day at the time the script is read, and
the script layout will be frozen according to that reference. That means that if the script is directly
played, the actual times will match the absolute timestamps up to the sound controller's clock accuracy,
but if the user somehow pauses the playback or seeks, all times will be shifted accordingly.

tedcaptions
JSON captions used for <http://www.ted.com/>.

TED does not provide links to the captions, but they can be guessed from the page. The file
tools/bookmarklets.html from the FFmpeg source tree contains a bookmarklet to expose them.

This demuxer accepts the following option:

start_time
Set the start time of the TED talk, in milliseconds. The default is 15000 (15s). It is used to sync
the captions with the downloadable videos, because they include a 15s intro.

Example: convert the captions to a format most players understand:

ffmpeg -i http://www.ted.com/talks/subtitles/id/1/lang/en talk1-en.srt

vapoursynth
Vapoursynth wrapper.

Due to security concerns, Vapoursynth scripts will not be autodetected so the input format has to be
forced. For ff* CLI tools, add "-f vapoursynth" before the input "-i yourscript.vpy".

This demuxer accepts the following option:

max_script_size
The demuxer buffers the entire script into memory. Adjust this value to set the maximum buffer size,
which in turn, acts as a ceiling for the size of scripts that can be read. Default is 1 MiB.

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.

a64
A64 muxer for Commodore 64 video. Accepts a single "a64_multi" or "a64_multi5" codec video stream.

adts
Audio Data Transport Stream muxer. It accepts a single AAC stream.

Options

It accepts the following options:

write_id3v2 bool
Enable to write ID3v2.4 tags at the start of the stream. Default is disabled.

write_apetag bool
Enable to write APE tags at the end of the stream. Default is disabled.

write_mpeg2 bool
Enable to set MPEG version bit in the ADTS frame header to 1 which indicates MPEG-2. Default is 0,
which indicates MPEG-4.

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.

alp
Muxer for audio of High Voltage Software's Lego Racers game. It accepts a single ADPCM_IMA_ALP stream
with no more than 2 channels nor a sample rate greater than 44100 Hz.

Extensions: tun, pcm

Options

It accepts the following options:

type type
Set file type.

tun Set file type as music. Must have a sample rate of 22050 Hz.

pcm Set file type as sfx.

auto
Set file type as per output file extension. ".pcm" results in type "pcm" else type "tun" is set.
(default)

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).

flipped_raw_rgb
If set to true, store positive height for raw RGB bitmaps, which indicates bitmap is stored bottom-
up. Note that this option does not flip the bitmap which has to be done manually beforehand, e.g. by
using the vflip filter. Default is false and indicates bitmap is stored top down.

chromaprint
Chromaprint fingerprinter.

This muxer feeds audio data to the Chromaprint library, which generates a fingerprint for the provided
audio data. See <https://acoustid.org/chromaprint>

It takes a single signed native-endian 16-bit raw audio stream of at most 2 channels.

Options

silence_threshold
Threshold for detecting silence. Range is from -1 to 32767, where -1 disables silence detection.
Silence detection can only be used with version 3 of the algorithm. Silence detection must be
disabled for use with the AcoustID service. Default is -1.

algorithm
Version of algorithm to fingerprint with. Range is 0 to 4. Version 3 enables silence detection.
Default is 1.

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

raw Binary raw fingerprint

compressed
Binary compressed fingerprint

base64
Base64 compressed fingerprint (default)

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 framehash muxer.

hls
Apple HTTP Live Streaming muxer that segments MPEG-TS according to the HTTP Live Streaming (HLS)
specification.

It creates a playlist file, and one or more segment files. The output filename specifies the playlist
filename.

By default, the muxer creates a file for each segment produced. These files have the same name as the
playlist, followed by a sequential number and a .ts extension.

Make sure to require a closed GOP when encoding and to set the GOP size to fit your segment time
constraint.

For example, to convert an input file with ffmpeg:

ffmpeg -i in.mkv -c:v h264 -flags +cgop -g 30 -hls_time 1 out.m3u8

This example will produce the playlist, out.m3u8, and segment files: out0.ts, out1.ts, out2.ts, etc.

See also the segment muxer, which provides a more generic and flexible implementation of a segmenter, and
can be used to perform HLS segmentation.

Options

This muxer supports the following options:

hls_init_time duration
Set the initial target segment length. Default value is 0.

duration must be a time duration specification, see the Time duration section in the ffmpeg-utils(1)
manual.

Segment will be cut on the next key frame after this time has passed on the first m3u8 list. After
the initial playlist is filled ffmpeg will cut segments at duration equal to "hls_time"

hls_time duration
Set the target segment length. Default value is 2.

duration must be a time duration specification, see the Time duration section in the ffmpeg-utils(1)
manual. Segment will be cut on the next key frame after this time has passed.

hls_list_size size
Set the maximum number of playlist entries. If set to 0 the list file will contain all the segments.
Default value is 5.

hls_delete_threshold size
Set the number of unreferenced segments to keep on disk before "hls_flags delete_segments" deletes
them. Increase this to allow continue clients to download segments which were recently referenced in
the playlist. Default value is 1, meaning segments older than "hls_list_size+1" will be deleted.

hls_start_number_source
Start the playlist sequence number ("#EXT-X-MEDIA-SEQUENCE") according to the specified source.
Unless "hls_flags single_file" is set, it also specifies source of starting sequence numbers of
segment and subtitle filenames. In any case, if "hls_flags append_list" is set and read playlist
sequence number is greater than the specified start sequence number, then that value will be used as
start value.

It accepts the following values:

generic (default)
Set the starting sequence numbers according to start_number option value.

epoch
The start number will be the seconds since epoch (1970-01-01 00:00:00)

epoch_us
The start number will be the microseconds since epoch (1970-01-01 00:00:00)

datetime
The start number will be based on the current date/time as YYYYmmddHHMMSS. e.g. 20161231235759.

start_number number
Start the playlist sequence number ("#EXT-X-MEDIA-SEQUENCE") from the specified number when
hls_start_number_source value is generic. (This is the default case.) Unless "hls_flags single_file"
is set, it also specifies starting sequence numbers of segment and subtitle filenames. Default value
is 0.

hls_allow_cache allowcache
Explicitly set whether the client MAY (1) or MUST NOT (0) cache media segments.

hls_base_url baseurl
Append baseurl to every entry in the playlist. Useful to generate playlists with absolute paths.

Note that the playlist sequence number must be unique for each segment and it is not to be confused
with the segment filename sequence number which can be cyclic, for example if the wrap option is
specified.

hls_segment_filename filename
Set the segment filename. Unless "hls_flags single_file" is set, filename is used as a string format
with the segment number:

ffmpeg -i in.nut -hls_segment_filename 'file%03d.ts' out.m3u8

This example will produce the playlist, out.m3u8, and segment files: file000.ts, file001.ts,
file002.ts, etc.

filename may contain full path or relative path specification, but only the file name part without
any path info will be contained in the m3u8 segment list. Should a relative path be specified, the
path of the created segment files will be relative to the current working directory. When
strftime_mkdir is set, the whole expanded value of filename will be written into the m3u8 segment
list.

ffmpeg -i in.ts -b:v:0 1000k -b:v:1 256k -b:a:0 64k -b:a:1 32k \
-map 0:v -map 0:a -map 0:v -map 0:a -f hls -var_stream_map "v:0,a:0 v:1,a:1" \
-hls_segment_filename 'file_%v_%03d.ts' out_%v.m3u8

This example will produce the playlists segment file sets: file_0_000.ts, file_0_001.ts,
file_0_002.ts, etc. and file_1_000.ts, file_1_001.ts, file_1_002.ts, etc.

The string "%v" may be present in the filename or in the last directory name containing the file, but
only in one of them. (Additionally, %v may appear multiple times in the last sub-directory or
filename.) If the string %v is present in the directory name, then sub-directories are created after
expanding the directory name pattern. This enables creation of segments corresponding to different
variant streams in subdirectories.

ffmpeg -i in.ts -b:v:0 1000k -b:v:1 256k -b:a:0 64k -b:a:1 32k \
-map 0:v -map 0:a -map 0:v -map 0:a -f hls -var_stream_map "v:0,a:0 v:1,a:1" \
-hls_segment_filename 'vs%v/file_%03d.ts' vs%v/out.m3u8

This example will produce the playlists segment file sets: vs0/file_000.ts, vs0/file_001.ts,
vs0/file_002.ts, etc. and vs1/file_000.ts, vs1/file_001.ts, vs1/file_002.ts, etc.

strftime
Use strftime() on filename to expand the segment filename with localtime. The segment number is also
available in this mode, but to use it, you need to specify second_level_segment_index hls_flag and
%%d will be the specifier.

ffmpeg -i in.nut -strftime 1 -hls_segment_filename 'file-%Y%m%d-%s.ts' out.m3u8

This example will produce the playlist, out.m3u8, and segment files: file-20160215-1455569023.ts,
file-20160215-1455569024.ts, etc. Note: On some systems/environments, the %s specifier is not
available. See
strftime() documentation.

ffmpeg -i in.nut -strftime 1 -hls_flags second_level_segment_index -hls_segment_filename 'file-%Y%m%d-%%04d.ts' out.m3u8

This example will produce the playlist, out.m3u8, and segment files: file-20160215-0001.ts,
file-20160215-0002.ts, etc.

strftime_mkdir
Used together with -strftime_mkdir, it will create all subdirectories which is expanded in filename.

ffmpeg -i in.nut -strftime 1 -strftime_mkdir 1 -hls_segment_filename '%Y%m%d/file-%Y%m%d-%s.ts' out.m3u8

This example will create a directory 201560215 (if it does not exist), and then produce the playlist,
out.m3u8, and segment files: 20160215/file-20160215-1455569023.ts,
20160215/file-20160215-1455569024.ts, etc.

ffmpeg -i in.nut -strftime 1 -strftime_mkdir 1 -hls_segment_filename '%Y/%m/%d/file-%Y%m%d-%s.ts' out.m3u8

This example will create a directory hierarchy 2016/02/15 (if any of them do not exist), and then
produce the playlist, out.m3u8, and segment files: 2016/02/15/file-20160215-1455569023.ts,
2016/02/15/file-20160215-1455569024.ts, etc.

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

hls_key_info_file key_info_file
Use the information in key_info_file for segment encryption. The first line of key_info_file
specifies the key URI written to the playlist. The key URL is used to access the encryption key
during playback. The second line specifies the path to the key file used to obtain the key during the
encryption process. The key file is read as a single packed array of 16 octets in binary format. The
optional third line specifies the initialization vector (IV) as a hexadecimal string to be used
instead of the segment sequence number (default) for encryption. Changes to key_info_file will result
in segment encryption with the new key/IV and an entry in the playlist for the new key URI/IV if
"hls_flags periodic_rekey" is enabled.

Key info file format:

<key URI>
<key file path>
<IV> (optional)

Example key URIs:

http://server/file.key
/path/to/file.key
file.key

Example key file paths:

file.key
/path/to/file.key

Example IV:

0123456789ABCDEF0123456789ABCDEF

Key info file example:

http://server/file.key
/path/to/file.key
0123456789ABCDEF0123456789ABCDEF

Example shell script:

#!/bin/sh
BASE_URL=${1:-'.'}
openssl rand 16 > file.key
echo $BASE_URL/file.key > file.keyinfo
echo file.key >> file.keyinfo
echo $(openssl rand -hex 16) >> file.keyinfo
ffmpeg -f lavfi -re -i testsrc -c:v h264 -hls_flags delete_segments \
-hls_key_info_file file.keyinfo out.m3u8

-hls_enc enc
Enable (1) or disable (0) the AES128 encryption. When enabled every segment generated is encrypted
and the encryption key is saved as playlist name.key.

-hls_enc_key key
16-octet key to encrypt the segments, by default it is randomly generated.

-hls_enc_key_url keyurl
If set, keyurl is prepended instead of baseurl to the key filename in the playlist.

-hls_enc_iv iv
16-octet initialization vector for every segment instead of the autogenerated ones.

hls_segment_type flags
Possible values:

mpegts
Output segment files in MPEG-2 Transport Stream format. This is compatible with all HLS versions.

fmp4
Output segment files in fragmented MP4 format, similar to MPEG-DASH. fmp4 files may be used in
HLS version 7 and above.

hls_fmp4_init_filename filename
Set filename to the fragment files header file, default filename is init.mp4.

Use "-strftime 1" on filename to expand the segment filename with localtime.

ffmpeg -i in.nut -hls_segment_type fmp4 -strftime 1 -hls_fmp4_init_filename "%s_init.mp4" out.m3u8

This will produce init like this 1602678741_init.mp4

hls_fmp4_init_resend
Resend init file after m3u8 file refresh every time, default is 0.

When "var_stream_map" is set with two or more variant streams, the filename pattern must contain the
string "%v", this string specifies the position of variant stream index in the generated init file
names. The string "%v" may be present in the filename or in the last directory name containing the
file. If the string is present in the directory name, then sub-directories are created after
expanding the directory name pattern. This enables creation of init files corresponding to different
variant streams in subdirectories.

hls_flags flags
Possible values:

single_file
If this flag is set, the muxer will store all segments in a single MPEG-TS file, and will use
byte ranges in the playlist. HLS playlists generated with this way will have the version number
4. For example:

ffmpeg -i in.nut -hls_flags single_file out.m3u8

Will produce the playlist, out.m3u8, and a single segment file, out.ts.

delete_segments
Segment files removed from the playlist are deleted after a period of time equal to the duration
of the segment plus the duration of the playlist.

append_list
Append new segments into the end of old segment list, and remove the "#EXT-X-ENDLIST" from the
old segment list.

round_durations
Round the duration info in the playlist file segment info to integer values, instead of using
floating point. If there are no other features requiring higher HLS versions be used, then this
will allow ffmpeg to output a HLS version 2 m3u8.

discont_start
Add the "#EXT-X-DISCONTINUITY" tag to the playlist, before the first segment's information.

omit_endlist
Do not append the "EXT-X-ENDLIST" tag at the end of the playlist.

periodic_rekey
The file specified by "hls_key_info_file" will be checked periodically and detect updates to the
encryption info. Be sure to replace this file atomically, including the file containing the AES
encryption key.

independent_segments
Add the "#EXT-X-INDEPENDENT-SEGMENTS" to playlists that has video segments and when all the
segments of that playlist are guaranteed to start with a Key frame.

iframes_only
Add the "#EXT-X-I-FRAMES-ONLY" to playlists that has video segments and can play only I-frames in
the "#EXT-X-BYTERANGE" mode.

split_by_time
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. This flag should be used with the "hls_time" option.

program_date_time
Generate "EXT-X-PROGRAM-DATE-TIME" tags.

second_level_segment_index
Makes it possible to use segment indexes as %%d in hls_segment_filename expression besides
date/time values when strftime is on. To get fixed width numbers with trailing zeroes, %%0xd
format is available where x is the required width.

second_level_segment_size
Makes it possible to use segment sizes (counted in bytes) as %%s in hls_segment_filename
expression besides date/time values when strftime is on. To get fixed width numbers with
trailing zeroes, %%0xs format is available where x is the required width.

second_level_segment_duration
Makes it possible to use segment duration (calculated in microseconds) as %%t in
hls_segment_filename expression besides date/time values when strftime is on. To get fixed width
numbers with trailing zeroes, %%0xt format is available where x is the required width.

ffmpeg -i sample.mpeg \
-f hls -hls_time 3 -hls_list_size 5 \
-hls_flags second_level_segment_index+second_level_segment_size+second_level_segment_duration \
-strftime 1 -strftime_mkdir 1 -hls_segment_filename "segment_%Y%m%d%H%M%S_%%04d_%%08s_%%013t.ts" stream.m3u8

This will produce segments like this: segment_20170102194334_0003_00122200_0000003000000.ts,
segment_20170102194334_0004_00120072_0000003000000.ts etc.

temp_file
Write segment data to filename.tmp and rename to filename only once the segment is complete. A
webserver serving up segments can be configured to reject requests to *.tmp to prevent access to
in-progress segments before they have been added to the m3u8 playlist. This flag also affects how
m3u8 playlist files are created. If this flag is set, all playlist files will written into
temporary file and renamed after they are complete, similarly as segments are handled. But
playlists with "file" protocol and with type ("hls_playlist_type") other than "vod" are always
written into temporary file regardless of this flag. Master playlist files ("master_pl_name"), if
any, with "file" protocol, are always written into temporary file regardless of this flag if
"master_pl_publish_rate" value is other than zero.

hls_playlist_type event
Emit "#EXT-X-PLAYLIST-TYPE:EVENT" in the m3u8 header. Forces hls_list_size to 0; the playlist can
only be appended to.

hls_playlist_type vod
Emit "#EXT-X-PLAYLIST-TYPE:VOD" in the m3u8 header. Forces hls_list_size to 0; the playlist must not
change.

method
Use the given HTTP method to create the hls files.

ffmpeg -re -i in.ts -f hls -method PUT http://example.com/live/out.m3u8

This example will upload all the mpegts segment files to the HTTP server using the HTTP PUT method,
and update the m3u8 files every "refresh" times using the same method. Note that the HTTP server
must support the given method for uploading files.

http_user_agent
Override User-Agent field in HTTP header. Applicable only for HTTP output.

var_stream_map
Map string which specifies how to group the audio, video and subtitle streams into different variant
streams. The variant stream groups are separated by space. Expected string format is like this
"a:0,v:0 a:1,v:1 ....". Here a:, v:, s: are the keys to specify audio, video and subtitle streams
respectively. Allowed values are 0 to 9 (limited just based on practical usage).

When there are two or more variant streams, the output filename pattern must contain the string "%v",
this string specifies the position of variant stream index in the output media playlist filenames.
The string "%v" may be present in the filename or in the last directory name containing the file. If
the string is present in the directory name, then sub-directories are created after expanding the
directory name pattern. This enables creation of variant streams in subdirectories.

ffmpeg -re -i in.ts -b:v:0 1000k -b:v:1 256k -b:a:0 64k -b:a:1 32k \
-map 0:v -map 0:a -map 0:v -map 0:a -f hls -var_stream_map "v:0,a:0 v:1,a:1" \
http://example.com/live/out_%v.m3u8

This example creates two hls variant streams. The first variant stream will contain video stream of
bitrate 1000k and audio stream of bitrate 64k and the second variant stream will contain video stream
of bitrate 256k and audio stream of bitrate 32k. Here, two media playlist with file names out_0.m3u8
and out_1.m3u8 will be created. If you want something meaningful text instead of indexes in result
names, you may specify names for each or some of the variants as in the following example.

ffmpeg -re -i in.ts -b:v:0 1000k -b:v:1 256k -b:a:0 64k -b:a:1 32k \
-map 0:v -map 0:a -map 0:v -map 0:a -f hls -var_stream_map "v:0,a:0,name:my_hd v:1,a:1,name:my_sd" \
http://example.com/live/out_%v.m3u8

This example creates two hls variant streams as in the previous one. But here, the two media
playlist with file names out_my_hd.m3u8 and out_my_sd.m3u8 will be created.

ffmpeg -re -i in.ts -b:v:0 1000k -b:v:1 256k -b:a:0 64k \
-map 0:v -map 0:a -map 0:v -f hls -var_stream_map "v:0 a:0 v:1" \
http://example.com/live/out_%v.m3u8

This example creates three hls variant streams. The first variant stream will be a video only stream
with video bitrate 1000k, the second variant stream will be an audio only stream with bitrate 64k and
the third variant stream will be a video only stream with bitrate 256k. Here, three media playlist
with file names out_0.m3u8, out_1.m3u8 and out_2.m3u8 will be created.

ffmpeg -re -i in.ts -b:v:0 1000k -b:v:1 256k -b:a:0 64k -b:a:1 32k \
-map 0:v -map 0:a -map 0:v -map 0:a -f hls -var_stream_map "v:0,a:0 v:1,a:1" \
http://example.com/live/vs_%v/out.m3u8

This example creates the variant streams in subdirectories. Here, the first media playlist is created
at http://example.com/live/vs_0/out.m3u8 and the second one at http://example.com/live/vs_1/out.m3u8.

ffmpeg -re -i in.ts -b:a:0 32k -b:a:1 64k -b:v:0 1000k -b:v:1 3000k \
-map 0:a -map 0:a -map 0:v -map 0:v -f hls \
-var_stream_map "a:0,agroup:aud_low a:1,agroup:aud_high v:0,agroup:aud_low v:1,agroup:aud_high" \
-master_pl_name master.m3u8 \
http://example.com/live/out_%v.m3u8

This example creates two audio only and two video only variant streams. In addition to the
#EXT-X-STREAM-INF tag for each variant stream in the master playlist, #EXT-X-MEDIA tag is also added
for the two audio only variant streams and they are mapped to the two video only variant streams with
audio group names 'aud_low' and 'aud_high'.

By default, a single hls variant containing all the encoded streams is created.

ffmpeg -re -i in.ts -b:a:0 32k -b:a:1 64k -b:v:0 1000k \
-map 0:a -map 0:a -map 0:v -f hls \
-var_stream_map "a:0,agroup:aud_low,default:yes a:1,agroup:aud_low v:0,agroup:aud_low" \
-master_pl_name master.m3u8 \
http://example.com/live/out_%v.m3u8

This example creates two audio only and one video only variant streams. In addition to the
#EXT-X-STREAM-INF tag for each variant stream in the master playlist, #EXT-X-MEDIA tag is also added
for the two audio only variant streams and they are mapped to the one video only variant streams with
audio group name 'aud_low', and the audio group have default stat is NO or YES.

By default, a single hls variant containing all the encoded streams is created.

ffmpeg -re -i in.ts -b:a:0 32k -b:a:1 64k -b:v:0 1000k \
-map 0:a -map 0:a -map 0:v -f hls \
-var_stream_map "a:0,agroup:aud_low,default:yes,language:ENG a:1,agroup:aud_low,language:CHN v:0,agroup:aud_low" \
-master_pl_name master.m3u8 \
http://example.com/live/out_%v.m3u8

By default, a single hls variant containing all the encoded streams is created.

ffmpeg -y -i input_with_subtitle.mkv \
-b:v:0 5250k -c:v h264 -pix_fmt yuv420p -profile:v main -level 4.1 \
-b:a:0 256k \
-c:s webvtt -c:a mp2 -ar 48000 -ac 2 -map 0:v -map 0:a:0 -map 0:s:0 \
-f hls -var_stream_map "v:0,a:0,s:0,sgroup:subtitle" \
-master_pl_name master.m3u8 -t 300 -hls_time 10 -hls_init_time 4 -hls_list_size \
10 -master_pl_publish_rate 10 -hls_flags \
delete_segments+discont_start+split_by_time ./tmp/video.m3u8

This example adds "#EXT-X-MEDIA" tag with "TYPE=SUBTITLES" in the master playlist with webvtt
subtitle group name 'subtitle'. Please make sure the input file has one text subtitle stream at
least.

cc_stream_map
Map string which specifies different closed captions groups and their attributes. The closed captions
stream groups are separated by space. Expected string format is like this "ccgroup:<group
name>,instreamid:<INSTREAM-ID>,language:<language code> ....". 'ccgroup' and 'instreamid' are
mandatory attributes. 'language' is an optional attribute. The closed captions groups configured
using this option are mapped to different variant streams by providing the same 'ccgroup' name in the
"var_stream_map" string. If "var_stream_map" is not set, then the first available ccgroup in
"cc_stream_map" is mapped to the output variant stream. The examples for these two use cases are
given below.

ffmpeg -re -i in.ts -b:v 1000k -b:a 64k -a53cc 1 -f hls \
-cc_stream_map "ccgroup:cc,instreamid:CC1,language:en" \
-master_pl_name master.m3u8 \
http://example.com/live/out.m3u8

This example adds "#EXT-X-MEDIA" tag with "TYPE=CLOSED-CAPTIONS" in the master playlist with group
name 'cc', language 'en' (english) and INSTREAM-ID 'CC1'. Also, it adds "CLOSED-CAPTIONS" attribute
with group name 'cc' for the output variant stream.

ffmpeg -re -i in.ts -b:v:0 1000k -b:v:1 256k -b:a:0 64k -b:a:1 32k \
-a53cc:0 1 -a53cc:1 1\
-map 0:v -map 0:a -map 0:v -map 0:a -f hls \
-cc_stream_map "ccgroup:cc,instreamid:CC1,language:en ccgroup:cc,instreamid:CC2,language:sp" \
-var_stream_map "v:0,a:0,ccgroup:cc v:1,a:1,ccgroup:cc" \
-master_pl_name master.m3u8 \
http://example.com/live/out_%v.m3u8

This example adds two "#EXT-X-MEDIA" tags with "TYPE=CLOSED-CAPTIONS" in the master playlist for the
INSTREAM-IDs 'CC1' and 'CC2'. Also, it adds "CLOSED-CAPTIONS" attribute with group name 'cc' for the
two output variant streams.

master_pl_name
Create HLS master playlist with the given name.

ffmpeg -re -i in.ts -f hls -master_pl_name master.m3u8 http://example.com/live/out.m3u8

This example creates HLS master playlist with name master.m3u8 and it is published at
http://example.com/live/

master_pl_publish_rate
Publish master play list repeatedly every after specified number of segment intervals.

ffmpeg -re -i in.ts -f hls -master_pl_name master.m3u8 \
-hls_time 2 -master_pl_publish_rate 30 http://example.com/live/out.m3u8

This example creates HLS master playlist with name master.m3u8 and keep publishing it repeatedly
every after 30 segments i.e. every after 60s.

http_persistent
Use persistent HTTP connections. Applicable only for HTTP output.

timeout
Set timeout for socket I/O operations. Applicable only for HTTP output.

ignore_io_errors
Ignore IO errors during open, write and delete. Useful for long-duration runs with network output.

headers
Set custom HTTP headers, can override built in default headers. Applicable only for HTTP output.

ico
ICO file muxer.

Microsoft's icon file format (ICO) has some strict limitations that should be noted:

• Size cannot exceed 256 pixels in any dimension

• Only BMP and PNG images can be stored

• If a BMP image is used, it must be one of the following pixel formats:

BMP Bit Depth FFmpeg Pixel Format
1bit pal8
4bit pal8
8bit pal8
16bit rgb555le
24bit bgr24
32bit bgra

• If a BMP image is used, it must use the BITMAPINFOHEADER DIB header

• If a PNG image is used, it must use the rgba pixel format

image2
Image file muxer.

The image file muxer writes video frames to image files.

The output filenames are specified by a pattern, which can be used to produce sequentially numbered
series of files. The pattern may contain the string "%d" or "%0Nd", this string specifies the position
of the characters representing a numbering in the filenames. If the form "%0Nd" is used, the string
representing the number in each filename is 0-padded to N digits. The literal character '%' can be
specified in the pattern with the string "%%".

If the pattern contains "%d" or "%0Nd", the first filename of the file list specified will contain the
number 1, all the following numbers will be sequential.

The pattern may contain a suffix which is used to automatically determine the format of the image files
to write.

For example the pattern "img-%03d.bmp" will specify a sequence of filenames of the form img-001.bmp,
img-002.bmp, ..., img-010.bmp, etc. The pattern "img%%-%d.jpg" will specify a sequence of filenames of
the form img%-1.jpg, img%-2.jpg, ..., img%-10.jpg, etc.

The image muxer supports the .Y.U.V image file format. This format is special in that that each image
frame consists of three files, for each of the YUV420P components. To read or write this image file
format, specify the name of the '.Y' file. The muxer will automatically open the '.U' and '.V' files as
required.

Options

frame_pts
If set to 1, expand the filename with pts from pkt->pts. Default value is 0.

start_number
Start the sequence from the specified number. Default value is 1.

update
If set to 1, the filename will always be interpreted as just a filename, not a pattern, and the
corresponding file will be continuously overwritten with new images. Default value is 0.

strftime
If set to 1, expand the filename with date and time information from strftime(). Default value is 0.

atomic_writing
Write output to a temporary file, which is renamed to target filename once writing is completed.
Default is disabled.

protocol_opts options_list
Set protocol options as a :-separated list of key=value parameters. Values containing the ":" special
character must be escaped.

Examples

The following example shows how to use ffmpeg for creating a sequence of files img-001.jpeg,
img-002.jpeg, ..., taking one image every second from the input video:

ffmpeg -i in.avi -vsync cfr -r 1 -f image2 'img-%03d.jpeg'

Note that with ffmpeg, if the format is not specified with the "-f" option and the output filename
specifies an image file format, the image2 muxer is automatically selected, so the previous command can
be written as:

ffmpeg -i in.avi -vsync cfr -r 1 'img-%03d.jpeg'

Note also that the pattern must not necessarily contain "%d" or "%0Nd", for example to create a single
image file img.jpeg from the start of the input video you can employ the command:

ffmpeg -i in.avi -f image2 -frames:v 1 img.jpeg

The strftime option allows you to expand the filename with date and time information. Check the
documentation of the strftime() function for the syntax.

For example to generate image files from the strftime() "%Y-%m-%d_%H-%M-%S" pattern, the following ffmpeg
command can be used:

ffmpeg -f v4l2 -r 1 -i /dev/video0 -f image2 -strftime 1 "%Y-%m-%d_%H-%M-%S.jpg"

You can set the file name with current frame's PTS:

ffmpeg -f v4l2 -r 1 -i /dev/video0 -copyts -f image2 -frame_pts true %d.jpg

A more complex example is to publish contents of your desktop directly to a WebDAV server every second:

ffmpeg -f x11grab -framerate 1 -i :0.0 -q:v 6 -update 1 -protocol_opts method=PUT http://example.com/desktop.jpg

matroska
Matroska container muxer.

This muxer implements the matroska and webm container specs.

Metadata

The recognized metadata settings in this muxer are:

title
Set title name provided to a single track. This gets mapped to the FileDescription element for a
stream written as attachment.

language
Specify the language of the track in the Matroska languages form.

The language can be either the 3 letters bibliographic ISO-639-2 (ISO 639-2/B) form (like "fre" for
French), or a language code mixed with a country code for specialities in languages (like "fre-ca"
for Canadian French).

stereo_mode
Set stereo 3D video layout of two views in a single video track.

The following values are recognized:

mono
video is not stereo

left_right
Both views are arranged side by side, Left-eye view is on the left

bottom_top
Both views are arranged in top-bottom orientation, Left-eye view is at bottom

top_bottom
Both views are arranged in top-bottom orientation, Left-eye view is on top

checkerboard_rl
Each view is arranged in a checkerboard interleaved pattern, Left-eye view being first

checkerboard_lr
Each view is arranged in a checkerboard interleaved pattern, Right-eye view being first

row_interleaved_rl
Each view is constituted by a row based interleaving, Right-eye view is first row

row_interleaved_lr
Each view is constituted by a row based interleaving, Left-eye view is first row

col_interleaved_rl
Both views are arranged in a column based interleaving manner, Right-eye view is first column

col_interleaved_lr
Both views are arranged in a column based interleaving manner, Left-eye view is first column

anaglyph_cyan_red
All frames are in anaglyph format viewable through red-cyan filters

right_left
Both views are arranged side by side, Right-eye view is on the left

anaglyph_green_magenta
All frames are in anaglyph format viewable through green-magenta filters

block_lr
Both eyes laced in one Block, Left-eye view is first

block_rl
Both eyes laced in one Block, Right-eye view is first

For example a 3D WebM clip can be created using the following command line:

ffmpeg -i sample_left_right_clip.mpg -an -c:v libvpx -metadata stereo_mode=left_right -y stereo_clip.webm

Options

This muxer supports the following options:

reserve_index_space
By default, this muxer writes the index for seeking (called cues in Matroska terms) at the end of the
file, because it cannot know in advance how much space to leave for the index at the beginning of the
file. However for some use cases -- e.g. streaming where seeking is possible but slow -- it is
useful to put the index at the beginning of the file.

If this option is set to a non-zero value, the muxer will reserve a given amount of space in the file
header and then try to write the cues there when the muxing finishes. If the reserved space does not
suffice, no Cues will be written, the file will be finalized and writing the trailer will return an
error. A safe size for most use cases should be about 50kB per hour of video.

Note that cues are only written if the output is seekable and this option will have no effect if it
is not.

cues_to_front
If set, the muxer will write the index at the beginning of the file by shifting the main data if
necessary. This can be combined with reserve_index_space in which case the data is only shifted if
the initially reserved space turns out to be insufficient.

This option is ignored if the output is unseekable.

default_mode
This option controls how the FlagDefault of the output tracks will be set. It influences which
tracks players should play by default. The default mode is passthrough.

infer
Every track with disposition default will have the FlagDefault set. Additionally, for each type
of track (audio, video or subtitle), if no track with disposition default of this type exists,
then the first track of this type will be marked as default (if existing). This ensures that the
default flag is set in a sensible way even if the input originated from containers that lack the
concept of default tracks.

infer_no_subs
This mode is the same as infer except that if no subtitle track with disposition default exists,
no subtitle track will be marked as default.

passthrough
In this mode the FlagDefault is set if and only if the AV_DISPOSITION_DEFAULT flag is set in the
disposition of the corresponding stream.

md5
MD5 testing format.

This is a variant of the hash muxer. Unlike that muxer, it defaults to using the MD5 hash function.

Examples

To compute the MD5 hash of the input converted to raw audio and video, and store it in the file out.md5:

ffmpeg -i INPUT -f md5 out.md5

You can print the MD5 to stdout with the command:

ffmpeg -i INPUT -f md5 -

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.

Fragmentation is enabled by setting one of the options that define how to cut the file into fragments:
"-frag_duration", "-frag_size", "-min_frag_duration", "-movflags +frag_keyframe" and "-movflags
+frag_custom". 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.

Options

frag_duration duration
Create fragments that are duration microseconds long.

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

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

movflags flags
Set various muxing switches. The following flags can be used:

frag_keyframe
Start a new fragment at each video keyframe.

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.)

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.

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.

skip_sidx
Skip writing of sidx atom. When bitrate overhead due to sidx atom is high, this option could be
used for cases where sidx atom is not mandatory. When global_sidx flag is enabled, this option
will be ignored.

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.

rtphint
Add RTP hinting tracks to the output file.

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.

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.

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).

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.

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

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.

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).

write_btrt bool
Force or disable writing bitrate box inside stsd box of a track. The box contains decoding buffer
size (in bytes), maximum bitrate and average bitrate for the track. The box will be skipped if none
of these values can be computed. Default is -1 or "auto", which will write the box only in MP4 mode.

write_prft
Write producer time reference box (PRFT) with a specified time source for the NTP field in the PRFT
box. Set value as wallclock to specify timesource as wallclock time and pts to specify timesource as
input packets' PTS values.

Setting value to pts is applicable only for a live encoding use case, where PTS values are set as as
wallclock time at the source. For example, an encoding use case with decklink capture source where
video_pts and audio_pts are set to abs_wallclock.

empty_hdlr_name bool
Enable to skip writing the name inside a "hdlr" box. Default is "false".

movie_timescale scale
Set the timescale written in the movie header box ("mvhd"). Range is 1 to INT_MAX. Default is 1000.

video_track_timescale scale
Set the timescale used for video tracks. Range is 0 to INT_MAX. If set to 0, the timescale is
automatically set based on the native stream time base. Default is 0.

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)

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 hexadecimal value between 0x01 and 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 PMTs. Default is 0x1000, minimum is 0x0020, maximum is 0x1ffa. This option has
no effect in m2ts mode where the PMT PID is fixed 0x0100.

mpegts_start_pid integer
Set the first PID for elementary streams. Default is 0x0100, minimum is 0x0020, maximum is 0x1ffa.
This option has no effect in m2ts mode where the elementary stream PIDs are fixed.

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.

nit Emit NIT table.

omit_rai
Disable writing of random access indicator.

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. Default is -1 which means that the PCR
interval will be determined automatically: 20 ms is used for CBR streams, the highest multiple of the
frame duration which is less than 100 ms is used for VBR streams.

pat_period duration
Maximum time in seconds between PAT/PMT tables. Default is 0.1.

sdt_period duration
Maximum time in seconds between SDT tables. Default is 0.5.

nit_period duration
Maximum time in seconds between NIT tables. Default is 0.5.

tables_version integer
Set PAT, PMT, SDT and NIT 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_opatom
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 and mxf_opatom 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.

raw muxers
Raw muxers accept a single stream matching the designated codec. They do not store timestamps or
metadata. The recognized extension is the same as the muxer name unless indicated otherwise.

ac3

Dolby Digital, also known as AC-3, audio.

adx

CRI Middleware ADX audio.

This muxer will write out the total sample count near the start of the first packet when the output is
seekable and the count can be stored in 32 bits.

aptx

aptX (Audio Processing Technology for Bluetooth) audio.

aptx_hd

aptX HD (Audio Processing Technology for Bluetooth) audio.

Extensions: aptxhd

avs2

AVS2-P2/IEEE1857.4 video.

Extensions: avs, avs2

cavsvideo

Chinese AVS (Audio Video Standard) video.

Extensions: cavs

codec2raw

Codec 2 audio.

No extension is registered so format name has to be supplied e.g. with the ffmpeg CLI tool "-f
codec2raw".

data

Data muxer accepts a single stream with any codec of any type. The input stream has to be selected using
the "-map" option with the ffmpeg CLI tool.

No extension is registered so format name has to be supplied e.g. with the ffmpeg CLI tool "-f data".

dirac

BBC Dirac video. The Dirac Pro codec is a subset and is standardized as SMPTE VC-2.

Extensions: drc, vc2

dnxhd

Avid DNxHD video. It is standardized as SMPTE VC-3. Accepts DNxHR streams.

Extensions: dnxhd, dnxhr

dts

DTS Coherent Acoustics (DCA) audio.

eac3

Dolby Digital Plus, also known as Enhanced AC-3, audio.

evc

MPEG-5 Essential Video Coding (EVC) / EVC / MPEG-5 Part 1 EVC video.

Extensions: evc

g722

ITU-T G.722 audio.

g723_1

ITU-T G.723.1 audio.

Extensions: tco, rco

g726

ITU-T G.726 big-endian ("left-justified") audio.

No extension is registered so format name has to be supplied e.g. with the ffmpeg CLI tool "-f g726".

g726le

ITU-T G.726 little-endian ("right-justified") audio.

No extension is registered so format name has to be supplied e.g. with the ffmpeg CLI tool "-f g726le".

gsm

Global System for Mobile Communications audio.

h261

ITU-T H.261 video.

h263

ITU-T H.263 / H.263-1996, H.263+ / H.263-1998 / H.263 version 2 video.

h264

ITU-T H.264 / MPEG-4 Part 10 AVC video. Bitstream shall be converted to Annex B syntax if it's in length-
prefixed mode.

Extensions: h264, 264

hevc

ITU-T H.265 / MPEG-H Part 2 HEVC video. Bitstream shall be converted to Annex B syntax if it's in length-
prefixed mode.

Extensions: hevc, h265, 265

m4v

MPEG-4 Part 2 video.

mjpeg

Motion JPEG video.

Extensions: mjpg, mjpeg

mlp

Meridian Lossless Packing, also known as Packed PCM, audio.

mp2

MPEG-1 Audio Layer II audio.

Extensions: mp2, m2a, mpa

mpeg1video

MPEG-1 Part 2 video.

Extensions: mpg, mpeg, m1v

mpeg2video

ITU-T H.262 / MPEG-2 Part 2 video.

Extensions: m2v

obu

AV1 low overhead Open Bitstream Units muxer. Temporal delimiter OBUs will be inserted in all temporal
units of the stream.

rawvideo

Raw uncompressed video.

Extensions: yuv, rgb

sbc

Bluetooth SIG low-complexity subband codec audio.

Extensions: sbc, msbc

truehd

Dolby TrueHD audio.

Extensions: thd

vc1

SMPTE 421M / VC-1 video.

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.

min_seg_duration time
Set minimum segment duration to time, the value must be a duration specification. This prevents the
muxer ending segments at a duration below this value. Only effective with "segment_time". Default
value is "0".

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.

Make sure to require a closed GOP when encoding and to set the GOP size to fit your segment time
constraint.

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 hevc -flags +cgop -g 60 -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).

streamhash
Per stream hash testing format.

This muxer computes and prints a cryptographic hash of all the input frames, on a per-stream basis. This
can be used for equality checks without having to do a complete binary comparison.

By default audio frames are converted to signed 16-bit raw audio and video frames to raw video before
computing the hash, but the output of explicit conversions to other codecs can also be used. Timestamps
are ignored. It uses the SHA-256 cryptographic hash function by default, but supports several other
algorithms.

The output of the muxer consists of one line per stream of the form: streamindex,streamtype,algo=hash,
where streamindex is the index of the mapped stream, streamtype is a single character indicating the type
of stream, algo is a short string representing the hash function used, and hash is a hexadecimal number
representing the computed hash.

Examples

To compute the SHA-256 hash of the input converted to raw audio and video, and store it in the file
out.sha256:

ffmpeg -i INPUT -f streamhash out.sha256

To print an MD5 hash to stdout use the command:

ffmpeg -i INPUT -f streamhash -hash md5 -

METADATA

       FFmpeg is able to dump metadata from media files into a simple UTF-8-encoded INI-like text file and  then
       load it back using the metadata muxer/demuxer.

       The file format is as follows:

       1.  A  file  consists  of  a  header and a number of metadata tags divided into sections, each on its own
           line.

       2.  The header is a ;FFMETADATA string, followed by a version number (now 1).

       3.  Metadata tags are of the form key=value

       4.  Immediately after header follows global metadata

       5.  After global metadata there may be sections with per-stream/per-chapter metadata.

       6.  A section starts with the section name in uppercase (i.e. STREAM or CHAPTER) in brackets ([,  ])  and
           ends with next section or end of file.

       7.  At  the  beginning  of  a  chapter section there may be an optional timebase to be used for start/end
           values. It must be in form TIMEBASE=num/den, where num and den  are  integers.  If  the  timebase  is
           missing then start/end times are assumed to be in nanoseconds.

           Next a chapter section must contain chapter start and end times in form START=num, END=num, where num
           is a positive integer.

       8.  Empty lines and lines starting with ; or # are ignored.

       9.  Metadata keys or values containing special characters (=, ;, #, \ and a newline) must be escaped with
           a backslash \.

       10. Note  that  whitespace  in  metadata  (e.g.  foo = bar) is considered to be a part of the tag (in the
           example above key is foo , value is
            bar).

       A ffmetadata file might look like this:

               ;FFMETADATA1
               title=bike\\shed
               ;this is a comment
               artist=FFmpeg troll team

               [CHAPTER]
               TIMEBASE=1/1000
               START=0
               #chapter ends at 0:01:00
               END=60000
               title=chapter \#1
               [STREAM]
               title=multi\
               line

       By using the ffmetadata muxer and demuxer it is possible to extract metadata from an  input  file  to  an
       ffmetadata file, and then transcode the file into an output file with the edited ffmetadata file.

       Extracting an ffmetadata file with ffmpeg goes as follows:

               ffmpeg -i INPUT -f ffmetadata FFMETADATAFILE

       Reinserting edited metadata information from the FFMETADATAFILE file can be done as:

               ffmpeg -i INPUT -i FFMETADATAFILE -map_metadata 1 -codec copy OUTPUT

AUTHORS

       The FFmpeg developers.

       For  details  about  the  authorship, see the Git history of the project (https://git.ffmpeg.org/ffmpeg),
       e.g. by typing the command git log in the FFmpeg source directory, or browsing the online  repository  at
       <https://git.ffmpeg.org/ffmpeg>.

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

                                                                                               FFMPEG-FORMATS(1)

NAME

DESCRIPTION

FORMAT OPTIONS

DEMUXERS

MUXERS

METADATA

SEE ALSO

AUTHORS