@chapter Muxers
 @c man begin 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 @code{--list-muxers}.
 
 You can disable all the muxers with the configure option
 @code{--disable-muxers} and selectively enable / disable single muxers
 with the options @code{--enable-muxer=@var{MUXER}} /
 @code{--disable-muxer=@var{MUXER}}.
 
 The option @code{-formats} of the ff* tools will display the list of
 enabled muxers.
 
 A description of some of the currently available muxers follows.
 

 @anchor{aiff}
 @section aiff
 
 Audio Interchange File Format muxer.
 

 @subsection Options
 

 It accepts the following options:
 
 @table @option
 @item write_id3v2
 Enable ID3v2 tags writing when set to 1. Default is 0 (disabled).
 
 @item 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.
 
 @end table
 

 @anchor{crc}

 @section 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=0x@var{CRC}, where @var{CRC} is a hexadecimal number 0-padded to
 8 digits containing the CRC for all the decoded input frames.
 

 See also the @ref{framecrc} muxer.
 
 @subsection Examples
 

 For example to compute the CRC of the input, and store it in the file
 @file{out.crc}:
 @example
 ffmpeg -i INPUT -f crc out.crc
 @end example
 
 You can print the CRC to stdout with the command:
 @example
 ffmpeg -i INPUT -f crc -
 @end example
 

 You can select the output format of each frame with @command{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:
 @example

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

 @end example
 

 @anchor{framecrc}
 @section 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:
 @example
 @var{stream_index}, @var{packet_dts}, @var{packet_pts}, @var{packet_duration}, @var{packet_size}, 0x@var{CRC}
 @end example

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

 @subsection Examples
 

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

 @example
 ffmpeg -i INPUT -f framecrc out.crc
 @end example
 

 To print the information to stdout, use the command:

 @example
 ffmpeg -i INPUT -f framecrc -
 @end example
 

 With @command{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:
 @example

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

 @end example
 

 See also the @ref{crc} muxer.

 @anchor{framemd5}
 @section framemd5
 
 Per-packet MD5 testing format.
 
 This muxer computes and prints the MD5 hash 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
 hash.
 
 The output of the muxer consists of a line for each audio and video
 packet of the form:
 @example
 @var{stream_index}, @var{packet_dts}, @var{packet_pts}, @var{packet_duration}, @var{packet_size}, @var{MD5}
 @end example
 
 @var{MD5} is a hexadecimal number representing the computed MD5 hash
 for the packet.
 

 @subsection Examples
 

 For example to compute the MD5 of the audio and video frames in
 @file{INPUT}, converted to raw audio and video packets, and store it
 in the file @file{out.md5}:
 @example
 ffmpeg -i INPUT -f framemd5 out.md5
 @end example
 
 To print the information to stdout, use the command:
 @example
 ffmpeg -i INPUT -f framemd5 -
 @end example
 
 See also the @ref{md5} muxer.
 

 @anchor{gif}
 @section gif
 
 Animated GIF muxer.
 
 It accepts the following options:
 
 @table @option
 @item loop
 Set the number of times to loop the output. Use @code{-1} for no loop, @code{0}
 for looping indefinitely (default).
 
 @item 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 @code{-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.
 @end table
 
 For example, to encode a gif looping 10 times, with a 5 seconds delay between
 the loops:
 @example
 ffmpeg -i INPUT -loop 10 -final_delay 500 out.gif
 @end example
 
 Note 1: if you wish to extract the frames in separate GIF files, you need to
 force the @ref{image2} muxer:
 @example
 ffmpeg -i INPUT -c:v gif -f image2 "out%d.gif"
 @end example
 
 Note 2: the GIF format has a very small time base: the delay between two frames
 can not be smaller than one centi second.
 

 @anchor{hls}
 @section 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 @command{ffmpeg}:

 @example

 ffmpeg -i in.nut out.m3u8

 @end example

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

 See also the @ref{segment} muxer, which provides a more generic and

 flexible implementation of a segmenter, and can be used to perform HLS

 segmentation.
 

 @subsection Options
 

 This muxer supports the following options:
 

 @table @option

 @item hls_time @var{seconds}
 Set the segment length in seconds. Default value is 2.
 
 @item hls_list_size @var{size}
 Set the maximum number of playlist entries. If set to 0 the list file
 will contain all the segments. Default value is 5.
 

 @item hls_ts_options @var{options_list}
 Set output format options using a :-separated list of key=value
 parameters. Values containing @code{:} special characters must be
 escaped.
 

 @item hls_wrap @var{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 @var{wrap}.
 
 @item start_number @var{number}
 Start the playlist sequence number from @var{number}. Default value is
 0.
 

 @item hls_allow_cache @var{allowcache}

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

 @item hls_base_url @var{baseurl}

 Append @var{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 @option{wrap} option is
 specified.

 @item hls_segment_filename @var{filename}
 Set the segment filename. Unless hls_flags single_file is set @var{filename}
 is used as a string format with the segment number:
 @example
 ffmpeg in.nut -hls_segment_filename 'file%03d.ts' out.m3u8
 @end example
 This example will produce the playlist, @file{out.m3u8}, and segment files:
 @file{file000.ts}, @file{file001.ts}, @file{file002.ts}, etc.
 

 @item 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:
 @example
 ffmpeg -i in.nut -hls_flags single_file out.m3u8
 @end example
 Will produce the playlist, @file{out.m3u8}, and a single segment file,
 @file{out.ts}.

 
 @item 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.

 @end table
 

 @anchor{ico}
 @section ico
 
 ICO file muxer.
 
 Microsoft's icon file format (ICO) has some strict limitations that should be noted:
 
 @itemize
 @item
 Size cannot exceed 256 pixels in any dimension
 
 @item
 Only BMP and PNG images can be stored
 
 @item
 If a BMP image is used, it must be one of the following pixel formats:
 @example
 BMP Bit Depth      FFmpeg Pixel Format
 1bit               pal8
 4bit               pal8
 8bit               pal8
 16bit              rgb555le
 24bit              bgr24
 32bit              bgra
 @end example
 
 @item
 If a BMP image is used, it must use the BITMAPINFOHEADER DIB header
 
 @item
 If a PNG image is used, it must use the rgba pixel format
 @end itemize
 

 @anchor{image2}

 @section 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 "%0@var{N}d", this string

 specifies the position of the characters representing a numbering in

 the filenames. If the form "%0@var{N}d" is used, the string

 representing the number in each filename is 0-padded to @var{N}
 digits. The literal character '%' can be specified in the pattern with
 the string "%%".
 
 If the pattern contains "%d" or "%0@var{N}d", 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 @file{img-001.bmp}, @file{img-002.bmp}, ...,
 @file{img-010.bmp}, etc.
 The pattern "img%%-%d.jpg" will specify a sequence of filenames of the
 form @file{img%-1.jpg}, @file{img%-2.jpg}, ..., @file{img%-10.jpg},
 etc.
 

 @subsection Examples
 

 The following example shows how to use @command{ffmpeg} for creating a

 sequence of files @file{img-001.jpeg}, @file{img-002.jpeg}, ...,
 taking one image every second from the input video:
 @example

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

 @end example
 

 Note that with @command{ffmpeg}, if the format is not specified with the

 @code{-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:
 @example

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

 @end example
 
 Note also that the pattern must not necessarily contain "%d" or
 "%0@var{N}d", for example to create a single image file
 @file{img.jpeg} from the input video you can employ the command:
 @example

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

 @end example
 

 The @option{strftime} option allows you to expand the filename with
 date and time information. Check the documentation of
 the @code{strftime()} function for the syntax.
 
 For example to generate image files from the @code{strftime()}
 "%Y-%m-%d_%H-%M-%S" pattern, the following @command{ffmpeg} command
 can be used:
 @example
 ffmpeg -f v4l2 -r 1 -i /dev/video0 -f image2 -strftime 1 "%Y-%m-%d_%H-%M-%S.jpg"
 @end example
 

 @subsection Options
 

 @table @option

 @item start_number

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

 @item 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.

 @item strftime

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

 @end table
 

 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.
 

 @section matroska
 
 Matroska container muxer.
 
 This muxer implements the matroska and webm container specs.
 

 @subsection Metadata
 

 The recognized metadata settings in this muxer are:
 
 @table @option

 @item title
 Set title name provided to a single track.

 @item 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).
 

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

 The following values are recognized:
 @table @samp

 @item mono
 video is not stereo
 @item left_right
 Both views are arranged side by side, Left-eye view is on the left
 @item bottom_top
 Both views are arranged in top-bottom orientation, Left-eye view is at bottom
 @item top_bottom
 Both views are arranged in top-bottom orientation, Left-eye view is on top
 @item checkerboard_rl
 Each view is arranged in a checkerboard interleaved pattern, Left-eye view being first
 @item checkerboard_lr
 Each view is arranged in a checkerboard interleaved pattern, Right-eye view being first
 @item row_interleaved_rl
 Each view is constituted by a row based interleaving, Right-eye view is first row
 @item row_interleaved_lr
 Each view is constituted by a row based interleaving, Left-eye view is first row
 @item col_interleaved_rl
 Both views are arranged in a column based interleaving manner, Right-eye view is first column
 @item col_interleaved_lr
 Both views are arranged in a column based interleaving manner, Left-eye view is first column
 @item anaglyph_cyan_red
 All frames are in anaglyph format viewable through red-cyan filters
 @item right_left
 Both views are arranged side by side, Right-eye view is on the left
 @item anaglyph_green_magenta
 All frames are in anaglyph format viewable through green-magenta filters
 @item block_lr
 Both eyes laced in one Block, Left-eye view is first
 @item block_rl
 Both eyes laced in one Block, Right-eye view is first
 @end table
 @end table
 
 For example a 3D WebM clip can be created using the following command line:
 @example
 ffmpeg -i sample_left_right_clip.mpg -an -c:v libvpx -metadata stereo_mode=left_right -y stereo_clip.webm
 @end example
 

 @subsection Options
 

 This muxer supports the following options:
 
 @table @option
 @item 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.
 @end table
 

 @anchor{md5}
 @section md5
 
 MD5 testing format.
 
 This muxer computes and prints the MD5 hash 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
 hash.
 
 The output of the muxer consists of a single line of the form:
 MD5=@var{MD5}, where @var{MD5} is a hexadecimal number representing
 the computed MD5 hash.
 
 For example to compute the MD5 hash of the input converted to raw
 audio and video, and store it in the file @file{out.md5}:
 @example
 ffmpeg -i INPUT -f md5 out.md5
 @end example
 
 You can print the MD5 to stdout with the command:
 @example
 ffmpeg -i INPUT -f md5 -
 @end example
 
 See also the @ref{framemd5} muxer.
 

 @section 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 @var{faststart} to the @var{movflags}, or
 using the @command{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.
 

 @subsection Options
 

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

 
 @table @option
 @item -moov_size @var{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.

 @item -movflags frag_keyframe
 Start a new fragment at each video keyframe.
 @item -frag_duration @var{duration}
 Create fragments that are @var{duration} microseconds long.
 @item -frag_size @var{size}
 Create fragments that contain up to @var{size} bytes of payload data.
 @item -movflags frag_custom
 Allow the caller to manually choose when to cut fragments, by
 calling @code{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 @command{ffmpeg}.)

 @item -min_frag_duration @var{duration}
 Don't create fragments that are shorter than @var{duration} microseconds long.

 @end table
 

 If more than one condition is specified, fragments are cut when
 one of the specified conditions is fulfilled. The exception to this is
 @code{-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:
 
 @table @option
 @item -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.
 @item -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.

 @item -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.

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

 @item -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.

 @item -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.

 @item -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).

 @end table
 

 @subsection Example
 

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

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

 @end example
 

 @section mp3
 

 The MP3 muxer writes a raw MP3 stream with the following optional features:
 @itemize @bullet
 @item
 An ID3v2 metadata header at the beginning (enabled by default). Versions 2.3 and
 2.4 are supported, the @code{id3v2_version} private option controls which one is
 used (3 or 4). Setting @code{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 @var{title} and @var{comment} map
 to APIC @var{description} and @var{picture type} respectively. See

 @url{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.
 

 @item
 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
 @code{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.

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

 Examples:
 
 Write an mp3 with an ID3v2.3 header and an ID3v1 footer:
 @example
 ffmpeg -i INPUT -id3v2_version 3 -write_id3v1 1 out.mp3
 @end example
 
 To attach a picture to an mp3 file select both the audio and the picture stream
 with @code{map}:
 @example
 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
 @end example
 

 Write a "clean" MP3 without any extra features:
 @example
 ffmpeg -i input.wav -write_xing 0 -id3v2_version 0 out.mp3

 @end example
 

 @section 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 @code{service_provider}
 and @code{service_name}. If they are not set the default for
 @code{service_provider} is "FFmpeg" and the default for
 @code{service_name} is "Service01".
 
 @subsection Options
 

 The muxer options are:
 
 @table @option
 @item -mpegts_original_network_id @var{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.
 @item -mpegts_transport_stream_id @var{number}
 Set the transport_stream_id (default 0x0001). This identifies a
 transponder in DVB.
 @item -mpegts_service_id @var{number}
 Set the service_id (default 0x0001) also known as program in DVB.

 @item -mpegts_service_type @var{number}
 Set the program service_type (default @var{digital_tv}), see below
 a list of pre defined values.

 @item -mpegts_pmt_start_pid @var{number}
 Set the first PID for PMT (default 0x1000, max 0x1f00).
 @item -mpegts_start_pid @var{number}
 Set the first PID for data packets (default 0x0100, max 0x0f00).

 @item -mpegts_m2ts_mode @var{number}
 Enable m2ts mode if set to 1. Default value is -1 which disables m2ts mode.
 @item -muxrate @var{number}

 Set a constant muxrate (default VBR).

 @item -pcr_period @var{numer}
 Override the default PCR retransmission time (default 20ms), ignored
 if variable muxrate is selected.

 @item -pes_payload_size @var{number}
 Set minimum PES packet payload in bytes.
 @item -mpegts_flags @var{flags}
 Set flags (see below).
 @item -mpegts_copyts @var{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.
 @item -tables_version @var{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:
 @example
 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
 ...
 @end example

 @end table
 

 Option mpegts_service_type accepts the following values:
 
 @table @option
 @item hex_value
 Any hexdecimal value between 0x01 to 0xff as defined in ETSI 300 468.
 @item digital_tv
 Digital TV service.
 @item digital_radio
 Digital Radio service.
 @item teletext
 Teletext service.
 @item advanced_codec_digital_radio
 Advanced Codec Digital Radio service.
 @item mpeg2_digital_hdtv
 MPEG2 Digital HDTV service.
 @item advanced_codec_digital_sdtv
 Advanced Codec Digital SDTV service.
 @item advanced_codec_digital_hdtv
 Advanced Codec Digital HDTV service.
 @end table
 

 Option mpegts_flags may take a set of such flags:
 
 @table @option
 @item resend_headers
 Reemit PAT/PMT before writing the next packet.
 @item latm
 Use LATM packetization for AAC.

 @end table
 

 @subsection Example

 
 @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
 @end example
 

 @section 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 @command{ffmpeg} you can use the

 command:
 @example
 ffmpeg -benchmark -i INPUT -f null out.null
 @end example
 
 Note that the above command does not read or write the @file{out.null}

 file, but specifying the output file is required by the @command{ffmpeg}

 syntax.
 
 Alternatively you can write the command as:
 @example
 ffmpeg -benchmark -i INPUT -f null -
 @end example
 

 @section nut
 
 @table @option
 @item -syncpoints @var{flags}
 Change the syncpoint usage in nut:
 @table @option
 @item @var{default} use the normal low-overhead seeking aids.
 @item @var{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, -@code{write_index} 0 can be used to disable
     all growing data tables, allowing to mux endless streams with limited memory

     and without these disadvantages.

 @item @var{timestamped} extend the syncpoint with a wallclock field.
 @end table
 The @var{none} and @var{timestamped} flags are experimental.

 @item -write_index @var{bool}
 Write index at the end, the default is to write an index.

 @end table
 
 @example

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

 @end example
 

 @section ogg

 Ogg container muxer.

 
 @table @option

 @item -page_duration @var{duration}
 Preferred page duration, in microseconds. The muxer will attempt to create
 pages that are approximately @var{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.

 @item -serial_offset @var{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.
 

 @end table
 

 @anchor{segment}

 @section 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 @ref{image2}, or by using a @code{strftime} template if
 the @option{strftime} option is enabled.

 @code{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.
 @code{ssegment} is a shorter alias for @code{stream_segment}.
 

 Every segment starts with a keyframe of the selected reference stream,
 which is set through the @option{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 @var{segment_list}. The list type is specified by the

 @var{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 @ref{hls} muxer, which provides a more specific
 implementation for HLS segmentation.
 

 @subsection Options
 

 The segment muxer supports the following options:

 
 @table @option

 @item reference_stream @var{specifier}
 Set the reference stream, as specified by the string @var{specifier}.

 If @var{specifier} is set to @code{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 @code{auto}.

 @item segment_format @var{format}
 Override the inner container format, by default it is guessed by the filename
 extension.

 @item segment_format_options @var{options_list}
 Set output format options using a :-separated list of key=value
 parameters. Values containing the @code{:} special character must be
 escaped.
 

 @item segment_list @var{name}

 Generate also a listfile named @var{name}. If not specified no
 listfile is generated.

 @item segment_list_flags @var{flags}
 Set flags affecting the segment list generation.
 
 It currently supports the following flags:

 @table @samp

 @item cache
 Allow caching (only affects M3U8 list files).
 
 @item live
 Allow live-friendly file generation.
 @end table
 

 @item segment_list_type @var{type}
 Select the listing format.
 @table @option
 @item @var{flat} use a simple flat list of entries.
 @item @var{hls} use a m3u8-like structure.
 @end table

 @item segment_list_size @var{size}

 Update the list file so that it contains at most @var{size}

 segments. If 0 the list file will contain all the segments. Default
 value is 0.
 

 @item segment_list_entry_prefix @var{prefix}

 Prepend @var{prefix} to each entry. Useful to generate absolute paths.

 By default no prefix is applied.

 The following values are recognized:

 @table @samp

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

 @item csv, ext

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

 each line matching the format (comma-separated values):

 @example
 @var{segment_filename},@var{segment_start_time},@var{segment_end_time}
 @end example
 
 @var{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.

 
 @var{segment_start_time} and @var{segment_end_time} specify
 the segment start and end time expressed in seconds.

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

 @samp{ext} is deprecated in favor or @samp{csv}.

 @item 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 @code{".ffcat"} or @code{".ffconcat"} will
 auto-select this format.
 

 @item m3u8

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

 
 A list file with the suffix @code{".m3u8"} will auto-select this format.

 @end table
 

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

 @item segment_time @var{time}

 Set segment duration to @var{time}, the value must be a duration
 specification. Default value is "2". See also the
 @option{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.

 @item segment_atclocktime @var{1|0}
 If set to "1" split at regular clock time intervals starting from 00:00
 o'clock. The @var{time} value specified in @option{segment_time} is
 used for setting the length of the splitting interval.
 
 For example with @option{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".
 

 @item segment_time_delta @var{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:
 @example
 PTS >= start_time - time_delta
 @end example
 
 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 @file{ffmpeg} option
 @var{force_key_frames}. The key frame times specified by
 @var{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*@var{frame_rate}) should address the worst case mismatch between

 the specified time and the time set by @var{force_key_frames}.
 

 @item segment_times @var{times}
 Specify a list of split points. @var{times} contains a list of comma

 separated duration specifications, in increasing order. See also
 the @option{segment_time} option.

 @item segment_frames @var{frames}
 Specify a list of split video frame numbers. @var{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.
 

 @item segment_wrap @var{limit}
 Wrap around segment index once it reaches @var{limit}.

 @item segment_start_number @var{number}
 Set the sequence number of the first segment. Defaults to @code{0}.
 

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

 @item break_non_keyframes @var{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 @code{0}.
 

 @item reset_timestamps @var{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 @code{0} by default.

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

 @end table
 

 @subsection Examples

 
 @itemize
 @item

 Remux the content of file @file{in.mkv} to a list of segments

 @file{out-000.nut}, @file{out-001.nut}, etc., and write the list of
 generated segments to @file{out.list}:

 @example

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

 @end example
 

 @item

 Segment input and set output format options for the output segments:
 @example
 ffmpeg -i in.mkv -f segment -segment_time 10 -segment_format_options movflags=+faststart out%03d.mp4
 @end example
 
 @item

 Segment the input file according to the split points specified by the
 @var{segment_times} option:

 @example

 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

 @end example
 
 @item

 Use the @command{ffmpeg} @option{force_key_frames}

 option to force key frames in the input at the specified location, together

 with the segment option @option{segment_time_delta} to account for

 possible roundings operated when setting key frame times.
 @example

 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

 @end example
 In order to force key frames on the input file, transcoding is
 required.
 
 @item

 Segment the input file by splitting the input file according to the

 frame numbers sequence specified with the @option{segment_frames} option:

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

 Convert the @file{in.mkv} to TS segments using the @code{libx264}

 and @code{libfaac} encoders:
 @example
 ffmpeg -i in.mkv -map 0 -codec:v libx264 -codec:a libfaac -f ssegment -segment_list out.list out%03d.ts
 @end example

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

 @end itemize
 

 @section smoothstreaming
 
 Smooth Streaming muxer generates a set of files (Manifest, chunks) suitable for serving with conventional web server.
 
 @table @option
 @item window_size
 Specify the number of fragments kept in the manifest. Default 0 (keep all).
 
 @item extra_window_size
 Specify the number of fragments kept outside of the manifest before removing from disk. Default 5.
 
 @item lookahead_count
 Specify the number of lookahead fragments. Default 2.
 
 @item min_frag_duration
 Specify the minimum fragment duration (in microseconds). Default 5000000.
 
 @item remove_at_exit
 Specify whether to remove all fragments when finished. Default 0 (do not remove).
 
 @end table
 

 @section 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 @command{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 @ref{quoting_and_escaping,,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

 @var{key}=@var{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:
 @table @option
 @item f
 Specify the format name. Useful if it cannot be guessed from the
 output name suffix.
 
 @item bsfs[/@var{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
 @code{/}. @var{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 ",".

 
 @item 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.

 @end table
 

 @subsection Examples
 

 @itemize
 @item
 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):

 @example

 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/"
 @end example
 

 @item
 Use @command{ffmpeg} to encode the input, and send the output

 to three different destinations. The @code{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 @file{out.aac} in order to make it contain only
 audio packets.
 @example
 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"
 @end example

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

 @end itemize

 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 @option{global_header} flag.
 

 @section 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:
 
 @itemize @bullet
 @item
 WebM DASH Specification: @url{https://sites.google.com/a/webmproject.org/wiki/adaptive-streaming/webm-dash-specification}
 @item
 ISO DASH Specification: @url{http://standards.iso.org/ittf/PubliclyAvailableStandards/c065274_ISO_IEC_23009-1_2014.zip}
 @end itemize

 
 @subsection Options
 
 This muxer supports the following options:
 
 @table @option
 @item 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.

 
 @item live
 Set this to 1 to create a live stream DASH Manifest. Default: 0.
 
 @item chunk_start_index
 Start index of the first chunk. This will go in the @samp{startNumber} attribute
 of the @samp{SegmentTemplate} element in the manifest. Default: 0.
 
 @item chunk_duration_ms
 Duration of each chunk in milliseconds. This will go in the @samp{duration}
 attribute of the @samp{SegmentTemplate} element in the manifest. Default: 1000.
 
 @item utc_timing_url
 URL of the page that will return the UTC timestamp in ISO format. This will go
 in the @samp{value} attribute of the @samp{UTCTiming} element in the manifest.
 Default: None.
 
 @item time_shift_buffer_depth
 Smallest time (in seconds) shifting buffer for which any Representation is
 guaranteed to be available. This will go in the @samp{timeShiftBufferDepth}
 attribute of the @samp{MPD} element. Default: 60.
 

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

 @end table
 
 @subsection Example
 @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
 @end example
 

 @section 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.
 
 @subsection Options
 
 This muxer supports the following options:
 
 @table @option
 @item chunk_start_index
 Index of the first chunk (defaults to 0).
 
 @item header
 Filename of the header where the initialization data will be written.
 
 @item audio_chunk_duration
 Duration of each audio chunk in milliseconds (defaults to 5000).
 @end table
 
 @subsection Example
 @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
 @end example
 

 @c man end MUXERS