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 -formats of the ff* tools will display the list of enabled muxers.

A description of some of the currently available muxers follows.

aiff
====

Audio Interchange File Format muxer.

Options
-------

It accepts the following options:

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

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

asf
===

Advanced Systems Format muxer.

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

Options
-------

It accepts the following options:

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

chromaprint
===========

Chromaprint fingerprinter

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

Options
-------

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

algorithm
     Algorithm index to fingerprint with.

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

     raw
          Binary raw fingerprint

     compressed
          Binary compressed fingerprint

     base64
          Base64 compressed fingerprint

crc
===

CRC (Cyclic Redundancy Check) testing format.

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

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

See also the framecrc muxer.

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 -

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.

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.

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.

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.

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.

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.

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 in 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 small time base: the delay between two frames can not be smaller than one centi second.

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.

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.

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.

Options
-------

This muxer supports the following options:

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
     Set the number after which the segment filename number (the number specified in each segment file) wraps. If set to 0 the number will be never wrapped. Default value is 0.

     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.

start_number NUMBER
     Start the playlist sequence number from NUMBER. 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 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.

use_localtime
     Use strftime on FILENAME to expand the segment filename with localtime. The segment number (%d) is not available in this mode.

          ffmpeg 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.

use_localtime_mkdir
     Used together with -use_localtime, it will create up to one subdirectory which is expanded in FILENAME.

          ffmpeg 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: 201560215/file-20160215-1455569023.ts, 201560215/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.

     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_flags 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.

hls_flags 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.

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

hls_flags round_durations
     Round the duration info in the playlist file segment info to integer values, instead of using floating point.

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

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

hls_flags 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.

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.

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.

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 1 -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 1 -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 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"

Options
-------

start_number
     Start the sequence from the specified number. Default value is 0.

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.

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.

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 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.

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.

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).

Example
-------

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

     ffmpeg -re <NORMAL INPUT/TRANSCODING OPTIONS> -movflags isml+frag_keyframe -f ismv http://server/publishingpoint.isml/Streams(Encoder1)

Audible AAX
-----------

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

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

mp3
===

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

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

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

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

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

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

Examples:

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

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

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

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

Write a "clean" MP3 without any extra features:

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

mpegts
======

MPEG transport stream muxer.

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

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

Options
-------

The muxer options are:

mpegts_original_network_id NUMBER
     Set the original_network_id (default 0x0001). 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.

mpegts_transport_stream_id NUMBER
     Set the transport_stream_id (default 0x0001). This identifies a transponder in DVB.

mpegts_service_id NUMBER
     Set the service_id (default 0x0001) also known as program in DVB.

mpegts_service_type NUMBER
     Set the program service_type (default DIGITAL_TV), see below a list of pre defined values.

mpegts_pmt_start_pid NUMBER
     Set the first PID for PMT (default 0x1000, max 0x1f00).

mpegts_start_pid NUMBER
     Set the first PID for data packets (default 0x0100, max 0x0f00).

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

muxrate NUMBER
     Set a constant muxrate (default VBR).

pcr_period NUMER
     Override the default PCR retransmission time (default 20ms), ignored if variable muxrate is selected.

pat_period NUMBER
     Maximal time in seconds between PAT/PMT tables.

sdt_period NUMBER
     Maximal time in seconds between SDT tables.

pes_payload_size NUMBER
     Set minimum PES packet payload in bytes.

mpegts_flags FLAGS
     Set flags (see below).

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

tables_version NUMBER
     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
          ...

Option mpegts_service_type accepts the following values:

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.

Option mpegts_flags may take a set of such flags:

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).

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" \
          -y out.ts

mxf, mxf_d10
============

MXF muxer.

Options
-------

The muxer options are:

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

null
====

Null muxer.

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

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

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

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

Alternatively you can write the command as:

     ffmpeg -benchmark -i INPUT -f null -

nut
===

-syncpoints FLAGS
     Change the syncpoint usage in nut:

     DEFAULT use the normal low-overhead seeking aids.

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

     TIMESTAMPED extend the syncpoint with a wallclock field.

     The NONE and TIMESTAMPED flags are experimental.

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

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

ogg
===

Ogg container muxer.

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

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

segment, stream_segment, ssegment
=================================

Basic stream segmenter.

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

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

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

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

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

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

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

Options
-------

The segment muxer supports the following options:

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

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

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

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

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

segment_list_flags FLAGS
     Set flags affecting the segment list generation.

     It currently supports the following flags:

     cache
          Allow caching (only affects M3U8 list files).

     live
          Allow live-friendly file generation.

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

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

segment_list_type TYPE
     Select the listing format.

     The following values are recognized:

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

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

               SEGMENT_FILENAME,SEGMENT_START_TIME,SEGMENT_END_TIME

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

          SEGMENT_START_TIME and SEGMENT_END_TIME specify the segment start and end time expressed in seconds.

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

          ext is deprecated in favor or csv.

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

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

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

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

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

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

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

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

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

     Default value is "0".

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

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

     Default value is "0".

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

     Assuming that the delay between the packets of your source is less than 0.5 second you can detect a leap second by specifying 0.5 as the duration.

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

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

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

Examples
--------

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

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

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

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

  * Segment the input file according to the split points specified by the SEGMENT_TIMES option:

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

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

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

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

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

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

  * Convert the in.mkv to TS segments using the libx264 and libfaac encoders:

          ffmpeg -i in.mkv -map 0 -codec:v libx264 -codec:a libfaac -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).

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.

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

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.

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

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

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

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

Examples
--------

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

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

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

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

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

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

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

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

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

webm_dash_manifest
==================

WebM DASH Manifest muxer.

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

For more information see:

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

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

Options
-------

This muxer supports the following options:

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

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

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

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

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

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

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

Example
-------

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

webm_chunk
==========

WebM Live Chunk Muxer.

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

Options
-------

This muxer supports the following options:

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

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

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

Example
-------

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