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1 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.


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1.1 aiff

Audio Interchange File Format muxer.


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1.1.1 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.


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1.2 asf

Advanced Systems Format muxer.

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


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1.2.1 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.


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1.3 avi

Audio Video Interleaved muxer.


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1.3.1 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 (ffmpeg-filters)the "amerge" section in the ffmpeg-filters manual).


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1.4 chromaprint

Chromaprint fingerprinter

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


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1.4.1 Options

silence_threshold

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

algorithm

Algorithm index to fingerprint with.

fp_format

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

raw

Binary raw fingerprint

compressed

Binary compressed fingerprint

base64

Base64 compressed fingerprint


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1.5 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 framecrc muxer.


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1.5.1 Examples

For example to compute the CRC of the input, and store it in the file ‘out.crc’:

ffmpeg -i INPUT -f crc out.crc

You can print the CRC to stdout with the command:

ffmpeg -i INPUT -f crc -

You can select the output format of each frame with ffmpeg by specifying the audio and video codec and format. For example to compute the CRC of the input audio converted to PCM unsigned 8-bit and the input video converted to MPEG-2 video, use the command:

ffmpeg -i INPUT -c:a pcm_u8 -c:v mpeg2video -f crc -

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1.6 flv

Adobe Flash Video Format muxer.

This muxer accepts the following options:

flvflags flags

Possible values:

aac_seq_header_detect

Place AAC sequence header based on audio stream data.

no_sequence_end

Disable sequence end tag.

no_metadata

Disable metadata tag.

no_duration_filesize

Disable duration and filesize in metadata when they are equal to zero at the end of stream. (Be used to non-seekable living stream).

add_keyframe_index

Used to facilitate seeking; particularly for HTTP pseudo streaming.


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1.7 dash

Dynamic Adaptive Streaming over HTTP (DASH) muxer that creates segments and manifest files according to the MPEG-DASH standard ISO/IEC 23009-1:2014.

For more information see:

It creates a MPD manifest file and segment files for each stream.

The segment filename might contain pre-defined identifiers used with SegmentTemplate as defined in section 5.3.9.4.4 of the standard. Available identifiers are "$RepresentationID$", "$Number$", "$Bandwidth$" and "$Time$".

ffmpeg -re -i <input> -map 0 -map 0 -c:a libfdk_aac -c:v libx264
-b:v:0 800k -b:v:1 300k -s:v:1 320x170 -profile:v:1 baseline
-profile:v:0 main -bf 1 -keyint_min 120 -g 120 -sc_threshold 0
-b_strategy 0 -ar:a:1 22050 -use_timeline 1 -use_template 1
-window_size 5 -adaptation_sets "id=0,streams=v id=1,streams=a"
-f dash /path/to/out.mpd
-min_seg_duration microseconds

Set the segment length in microseconds.

-window_size size

Set the maximum number of segments kept in the manifest.

-extra_window_size size

Set the maximum number of segments kept outside of the manifest before removing from disk.

-remove_at_exit remove

Enable (1) or disable (0) removal of all segments when finished.

-use_template template

Enable (1) or disable (0) use of SegmentTemplate instead of SegmentList.

-use_timeline timeline

Enable (1) or disable (0) use of SegmentTimeline in SegmentTemplate.

-single_file single_file

Enable (1) or disable (0) storing all segments in one file, accessed using byte ranges.

-single_file_name file_name

DASH-templated name to be used for baseURL. Implies single_file set to "1".

-init_seg_name init_name

DASH-templated name to used for the initialization segment. Default is "init-stream$RepresentationID$.m4s"

-media_seg_name segment_name

DASH-templated name to used for the media segments. Default is "chunk-stream$RepresentationID$-$Number%05d$.m4s"

-utc_timing_url utc_url

URL of the page that will return the UTC timestamp in ISO format. Example: "https://time.akamai.com/?iso"

-adaptation_sets adaptation_sets

Assign streams to AdaptationSets. Syntax is "id=x,streams=a,b,c id=y,streams=d,e" with x and y being the IDs of the adaptation sets and a,b,c,d and e are the indices of the mapped streams.

To map all video (or audio) streams to an AdaptationSet, "v" (or "a") can be used as stream identifier instead of IDs.

When no assignment is defined, this defaults to an AdaptationSet for each stream.


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1.8 framecrc

Per-packet CRC (Cyclic Redundancy Check) testing format.

This muxer computes and prints the Adler-32 CRC for each audio and video packet. 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 line for each audio and video packet of the form:

stream_index, packet_dts, packet_pts, packet_duration, packet_size, 0xCRC

CRC is a hexadecimal number 0-padded to 8 digits containing the CRC of the packet.


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1.8.1 Examples

For example to compute the CRC of the audio and video frames in ‘INPUT’, converted to raw audio and video packets, and store it in the file ‘out.crc’:

ffmpeg -i INPUT -f framecrc out.crc

To print the information to stdout, use the command:

ffmpeg -i INPUT -f framecrc -

With ffmpeg, you can select the output format to which the audio and video frames are encoded before computing the CRC for each packet by specifying the audio and video codec. For example, to compute the CRC of each decoded input audio frame converted to PCM unsigned 8-bit and of each decoded input video frame converted to MPEG-2 video, use the command:

ffmpeg -i INPUT -c:a pcm_u8 -c:v mpeg2video -f framecrc -

See also the crc muxer.


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1.9 framehash

Per-packet hash testing format.

This muxer computes and prints a cryptographic hash for each audio and video packet. This can be used for packet-by-packet equality checks without having to individually do a binary comparison on each.

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. It uses the SHA-256 cryptographic hash function by default, but supports several other algorithms.

The output of the muxer consists of a line for each audio and video packet of the form:

stream_index, packet_dts, packet_pts, packet_duration, packet_size, hash

hash is a hexadecimal number representing the computed hash for the packet.

hash algorithm

Use the cryptographic hash function specified by the string algorithm. Supported values include MD5, murmur3, RIPEMD128, RIPEMD160, RIPEMD256, RIPEMD320, SHA160, SHA224, SHA256 (default), SHA512/224, SHA512/256, SHA384, SHA512, CRC32 and adler32.


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1.9.1 Examples

To compute the SHA-256 hash of the audio and video frames in ‘INPUT’, converted to raw audio and video packets, and store it in the file ‘out.sha256’:

ffmpeg -i INPUT -f framehash out.sha256

To print the information to stdout, using the MD5 hash function, use the command:

ffmpeg -i INPUT -f framehash -hash md5 -

See also the hash muxer.


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1.10 framemd5

Per-packet MD5 testing format.

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


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1.10.1 Examples

To compute the MD5 hash of the audio and video frames in ‘INPUT’, converted to raw audio and video packets, and store it in the file ‘out.md5’:

ffmpeg -i INPUT -f framemd5 out.md5

To print the information to stdout, use the command:

ffmpeg -i INPUT -f framemd5 -

See also the framehash and md5 muxers.


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1.11 gif

Animated GIF muxer.

It accepts the following options:

loop

Set the number of times to loop the output. Use -1 for no loop, 0 for looping indefinitely (default).

final_delay

Force the delay (expressed in centiseconds) after the last frame. Each frame ends with a delay until the next frame. The default is -1, which is a special value to tell the muxer to re-use the previous delay. In case of a loop, you might want to customize this value to mark a pause for instance.

For example, to encode a gif looping 10 times, with a 5 seconds delay between the loops:

ffmpeg -i INPUT -loop 10 -final_delay 500 out.gif

Note 1: if you wish to extract the frames into separate GIF files, you need to force the image2 muxer:

ffmpeg -i INPUT -c:v gif -f image2 "out%d.gif"

Note 2: the GIF format has a very large time base: the delay between two frames can therefore not be smaller than one centi second.


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1.12 hash

Hash testing format.

This muxer computes and prints a cryptographic hash of all the input audio and video frames. 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 a single line of the form: algo=hash, where algo is a short string representing the hash function used, and hash is a hexadecimal number representing the computed hash.

hash algorithm

Use the cryptographic hash function specified by the string algorithm. Supported values include MD5, murmur3, RIPEMD128, RIPEMD160, RIPEMD256, RIPEMD320, SHA160, SHA224, SHA256 (default), SHA512/224, SHA512/256, SHA384, SHA512, CRC32 and adler32.


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1.12.1 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 hash out.sha256

To print an MD5 hash to stdout use the command:

ffmpeg -i INPUT -f hash -hash md5 -

See also the framehash muxer.


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1.13 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.

For example, to convert an input file with ffmpeg:

ffmpeg -i in.nut 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.


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1.13.1 Options

This muxer supports the following options:

hls_init_time seconds

Set the initial target segment length in seconds. Default value is 0. 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 seconds

Set the target segment length in seconds. Default value is 2. 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_ts_options options_list

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

hls_wrap wrap

This is a deprecated option, you can use hls_list_size and hls_flags delete_segments instead it

This option is useful to avoid to fill the disk with many segment files, and limits the maximum number of segment files written to disk to wrap.

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)

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 use_localtime_mkdir is set, the whole expanded value of filename will be written into the m3u8 segment list.

use_localtime

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 -use_localtime 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 -use_localtime 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.

use_localtime_mkdir

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

ffmpeg -i in.nut -use_localtime 1 -use_localtime_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 -use_localtime 1 -use_localtime_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_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

Hex-coded 16byte 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

Hex-coded 16byte initialization vector for every segment instead of the autogenerated ones.

hls_segment_type flags

Possible values:

mpegts

If this flag is set, the hls segment files will format to mpegts. the mpegts files is used in all hls versions.

fmp4

If this flag is set, the hls segment files will format to fragment mp4 looks like dash. the fmp4 files is used in hls after version 7.

hls_fmp4_init_filename filename

set filename to the fragment files header file, default filename is ‘init.mp4’.

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.

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.

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 use_localtime 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 use_localtime 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 use_localtime 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 \
   -use_localtime 1 -use_localtime_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.

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.


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1.14 ico

ICO file muxer.

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


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1.15 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.


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1.15.1 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"

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1.15.2 Options

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.

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.


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1.16 matroska

Matroska container muxer.

This muxer implements the matroska and webm container specs.


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1.16.1 Metadata

The recognized metadata settings in this muxer are:

title

Set title name provided to a single track.

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

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1.16.2 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 available space does not suffice, muxing will fail. 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.


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1.17 md5

MD5 testing format.

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


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1.17.1 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.


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1.18 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.


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1.18.1 Options

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

-moov_size bytes

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

-movflags frag_keyframe

Start a new fragment at each video keyframe.

-frag_duration duration

Create fragments that are duration microseconds long.

-frag_size size

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

-movflags frag_custom

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

-min_frag_duration duration

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

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

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

-movflags empty_moov

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

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

-movflags separate_moof

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

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

-movflags faststart

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

-movflags rtphint

Add RTP hinting tracks to the output file.

-movflags disable_chpl

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

-movflags omit_tfhd_offset

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

-movflags default_base_moof

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

-write_tmcd

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

-movflags negative_cts_offsets

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


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1.18.2 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)

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1.18.3 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

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1.19 mp3

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

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

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1.20 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’.


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1.20.1 Options

The muxer options are:

mpegts_transport_stream_id integer

Set the ‘transport_stream_id’. This identifies a transponder in DVB. Default is 0x0001.

mpegts_original_network_id integer

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

mpegts_service_id integer

Set the ‘service_id’, also known as program in DVB. Default is 0x0001.

mpegts_service_type integer

Set the program ‘service_type’. Default is digital_tv. Accepts the following options:

hex_value

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

digital_tv

Digital TV service.

digital_radio

Digital Radio service.

teletext

Teletext service.

advanced_codec_digital_radio

Advanced Codec Digital Radio service.

mpeg2_digital_hdtv

MPEG2 Digital HDTV service.

advanced_codec_digital_sdtv

Advanced Codec Digital SDTV service.

advanced_codec_digital_hdtv

Advanced Codec Digital HDTV service.

mpegts_pmt_start_pid integer

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

mpegts_start_pid integer

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

mpegts_m2ts_mode boolean

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

muxrate integer

Set a constant muxrate. Default is VBR.

pes_payload_size integer

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

mpegts_flags flags

Set mpegts flags. Accepts the following options:

resend_headers

Reemit PAT/PMT before writing the next packet.

latm

Use LATM packetization for AAC.

pat_pmt_at_frames

Reemit PAT and PMT at each video frame.

system_b

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

initial_discontinuity

Mark the initial packet of each stream as discontinuity.

resend_headers integer

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

mpegts_copyts boolean

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

omit_video_pes_length boolean

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

pcr_period integer

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

pat_period double

Maximum time in seconds between PAT/PMT tables.

sdt_period double

Maximum time in seconds between SDT tables.

tables_version integer

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

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

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1.20.2 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

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1.21 mxf, mxf_d10

MXF muxer.


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1.21.1 Options

The muxer options are:

store_user_comments bool

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


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1.22 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 -

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1.23 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, -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

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1.24 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.


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1.25 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.


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1.25.1 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 @ref{concat} demuxer.

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

m3u8

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

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

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

segment_time time

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

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

segment_atclocktime 1|0

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

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

Default value is "0".

segment_clocktime_offset duration

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

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

Default value is "0".

segment_clocktime_wrap_duration duration

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

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

segment_time_delta delta

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

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

PTS >= start_time - time_delta

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

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

segment_times times

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

segment_frames frames

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

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

segment_wrap limit

Wrap around segment index once it reaches limit.

segment_start_number number

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

strftime 1|0

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

break_non_keyframes 1|0

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

reset_timestamps 1|0

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

initial_offset offset

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

write_empty_segments 1|0

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


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1.25.2 Examples


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1.26 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).


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1.27 fifo

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

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

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

fifo_format

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

queue_size

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

format_opts

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

drop_pkts_on_overflow bool

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

attempt_recovery bool

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

max_recovery_attempts

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

recovery_wait_time duration

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

recovery_wait_streamtime bool

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

recover_any_error bool

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

restart_with_keyframe bool

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


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1.27.1 Examples


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1.28 tee

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

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

use_fifo bool

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

fifo_options

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

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

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

The following special options are also recognized:

f

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

bsfs[/spec]

Specify a list of bitstream filters to apply to the specified output.

use_fifo bool

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

fifo_options

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

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

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

select

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

onfail

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


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1.28.1 Examples

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


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1.29 webm_dash_manifest

WebM DASH Manifest muxer.

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

For more information see:


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1.29.1 Options

This muxer supports the following options:

adaptation_sets

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

live

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

chunk_start_index

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

chunk_duration_ms

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

utc_timing_url

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

time_shift_buffer_depth

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

minimum_update_period

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


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1.29.2 Example

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

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1.30 webm_chunk

WebM Live Chunk Muxer.

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


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1.30.1 Options

This muxer supports the following options:

chunk_start_index

Index of the first chunk (defaults to 0).

header

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

audio_chunk_duration

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


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1.30.2 Example

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

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