yading@10: @chapter Muxers
yading@10: @c man begin MUXERS
yading@10: 
yading@10: Muxers are configured elements in FFmpeg which allow writing
yading@10: multimedia streams to a particular type of file.
yading@10: 
yading@10: When you configure your FFmpeg build, all the supported muxers
yading@10: are enabled by default. You can list all available muxers using the
yading@10: configure option @code{--list-muxers}.
yading@10: 
yading@10: You can disable all the muxers with the configure option
yading@10: @code{--disable-muxers} and selectively enable / disable single muxers
yading@10: with the options @code{--enable-muxer=@var{MUXER}} /
yading@10: @code{--disable-muxer=@var{MUXER}}.
yading@10: 
yading@10: The option @code{-formats} of the ff* tools will display the list of
yading@10: enabled muxers.
yading@10: 
yading@10: A description of some of the currently available muxers follows.
yading@10: 
yading@10: @anchor{crc}
yading@10: @section crc
yading@10: 
yading@10: CRC (Cyclic Redundancy Check) testing format.
yading@10: 
yading@10: This muxer computes and prints the Adler-32 CRC of all the input audio
yading@10: and video frames. By default audio frames are converted to signed
yading@10: 16-bit raw audio and video frames to raw video before computing the
yading@10: CRC.
yading@10: 
yading@10: The output of the muxer consists of a single line of the form:
yading@10: CRC=0x@var{CRC}, where @var{CRC} is a hexadecimal number 0-padded to
yading@10: 8 digits containing the CRC for all the decoded input frames.
yading@10: 
yading@10: For example to compute the CRC of the input, and store it in the file
yading@10: @file{out.crc}:
yading@10: @example
yading@10: ffmpeg -i INPUT -f crc out.crc
yading@10: @end example
yading@10: 
yading@10: You can print the CRC to stdout with the command:
yading@10: @example
yading@10: ffmpeg -i INPUT -f crc -
yading@10: @end example
yading@10: 
yading@10: You can select the output format of each frame with @command{ffmpeg} by
yading@10: specifying the audio and video codec and format. For example to
yading@10: compute the CRC of the input audio converted to PCM unsigned 8-bit
yading@10: and the input video converted to MPEG-2 video, use the command:
yading@10: @example
yading@10: ffmpeg -i INPUT -c:a pcm_u8 -c:v mpeg2video -f crc -
yading@10: @end example
yading@10: 
yading@10: See also the @ref{framecrc} muxer.
yading@10: 
yading@10: @anchor{framecrc}
yading@10: @section framecrc
yading@10: 
yading@10: Per-packet CRC (Cyclic Redundancy Check) testing format.
yading@10: 
yading@10: This muxer computes and prints the Adler-32 CRC for each audio
yading@10: and video packet. By default audio frames are converted to signed
yading@10: 16-bit raw audio and video frames to raw video before computing the
yading@10: CRC.
yading@10: 
yading@10: The output of the muxer consists of a line for each audio and video
yading@10: packet of the form:
yading@10: @example
yading@10: @var{stream_index}, @var{packet_dts}, @var{packet_pts}, @var{packet_duration}, @var{packet_size}, 0x@var{CRC}
yading@10: @end example
yading@10: 
yading@10: @var{CRC} is a hexadecimal number 0-padded to 8 digits containing the
yading@10: CRC of the packet.
yading@10: 
yading@10: For example to compute the CRC of the audio and video frames in
yading@10: @file{INPUT}, converted to raw audio and video packets, and store it
yading@10: in the file @file{out.crc}:
yading@10: @example
yading@10: ffmpeg -i INPUT -f framecrc out.crc
yading@10: @end example
yading@10: 
yading@10: To print the information to stdout, use the command:
yading@10: @example
yading@10: ffmpeg -i INPUT -f framecrc -
yading@10: @end example
yading@10: 
yading@10: With @command{ffmpeg}, you can select the output format to which the
yading@10: audio and video frames are encoded before computing the CRC for each
yading@10: packet by specifying the audio and video codec. For example, to
yading@10: compute the CRC of each decoded input audio frame converted to PCM
yading@10: unsigned 8-bit and of each decoded input video frame converted to
yading@10: MPEG-2 video, use the command:
yading@10: @example
yading@10: ffmpeg -i INPUT -c:a pcm_u8 -c:v mpeg2video -f framecrc -
yading@10: @end example
yading@10: 
yading@10: See also the @ref{crc} muxer.
yading@10: 
yading@10: @anchor{framemd5}
yading@10: @section framemd5
yading@10: 
yading@10: Per-packet MD5 testing format.
yading@10: 
yading@10: This muxer computes and prints the MD5 hash for each audio
yading@10: and video packet. By default audio frames are converted to signed
yading@10: 16-bit raw audio and video frames to raw video before computing the
yading@10: hash.
yading@10: 
yading@10: The output of the muxer consists of a line for each audio and video
yading@10: packet of the form:
yading@10: @example
yading@10: @var{stream_index}, @var{packet_dts}, @var{packet_pts}, @var{packet_duration}, @var{packet_size}, @var{MD5}
yading@10: @end example
yading@10: 
yading@10: @var{MD5} is a hexadecimal number representing the computed MD5 hash
yading@10: for the packet.
yading@10: 
yading@10: For example to compute the MD5 of the audio and video frames in
yading@10: @file{INPUT}, converted to raw audio and video packets, and store it
yading@10: in the file @file{out.md5}:
yading@10: @example
yading@10: ffmpeg -i INPUT -f framemd5 out.md5
yading@10: @end example
yading@10: 
yading@10: To print the information to stdout, use the command:
yading@10: @example
yading@10: ffmpeg -i INPUT -f framemd5 -
yading@10: @end example
yading@10: 
yading@10: See also the @ref{md5} muxer.
yading@10: 
yading@10: @anchor{hls}
yading@10: @section hls
yading@10: 
yading@10: Apple HTTP Live Streaming muxer that segments MPEG-TS according to
yading@10: the HTTP Live Streaming specification.
yading@10: 
yading@10: It creates a playlist file and numbered segment files. The output
yading@10: filename specifies the playlist filename; the segment filenames
yading@10: receive the same basename as the playlist, a sequential number and
yading@10: a .ts extension.
yading@10: 
yading@10: @example
yading@10: ffmpeg -i in.nut out.m3u8
yading@10: @end example
yading@10: 
yading@10: @table @option
yading@10: @item -hls_time @var{seconds}
yading@10: Set the segment length in seconds.
yading@10: @item -hls_list_size @var{size}
yading@10: Set the maximum number of playlist entries.
yading@10: @item -hls_wrap @var{wrap}
yading@10: Set the number after which index wraps.
yading@10: @item -start_number @var{number}
yading@10: Start the sequence from @var{number}.
yading@10: @end table
yading@10: 
yading@10: @anchor{ico}
yading@10: @section ico
yading@10: 
yading@10: ICO file muxer.
yading@10: 
yading@10: Microsoft's icon file format (ICO) has some strict limitations that should be noted:
yading@10: 
yading@10: @itemize
yading@10: @item
yading@10: Size cannot exceed 256 pixels in any dimension
yading@10: 
yading@10: @item
yading@10: Only BMP and PNG images can be stored
yading@10: 
yading@10: @item
yading@10: If a BMP image is used, it must be one of the following pixel formats:
yading@10: @example
yading@10: BMP Bit Depth      FFmpeg Pixel Format
yading@10: 1bit               pal8
yading@10: 4bit               pal8
yading@10: 8bit               pal8
yading@10: 16bit              rgb555le
yading@10: 24bit              bgr24
yading@10: 32bit              bgra
yading@10: @end example
yading@10: 
yading@10: @item
yading@10: If a BMP image is used, it must use the BITMAPINFOHEADER DIB header
yading@10: 
yading@10: @item
yading@10: If a PNG image is used, it must use the rgba pixel format
yading@10: @end itemize
yading@10: 
yading@10: @anchor{image2}
yading@10: @section image2
yading@10: 
yading@10: Image file muxer.
yading@10: 
yading@10: The image file muxer writes video frames to image files.
yading@10: 
yading@10: The output filenames are specified by a pattern, which can be used to
yading@10: produce sequentially numbered series of files.
yading@10: The pattern may contain the string "%d" or "%0@var{N}d", this string
yading@10: specifies the position of the characters representing a numbering in
yading@10: the filenames. If the form "%0@var{N}d" is used, the string
yading@10: representing the number in each filename is 0-padded to @var{N}
yading@10: digits. The literal character '%' can be specified in the pattern with
yading@10: the string "%%".
yading@10: 
yading@10: If the pattern contains "%d" or "%0@var{N}d", the first filename of
yading@10: the file list specified will contain the number 1, all the following
yading@10: numbers will be sequential.
yading@10: 
yading@10: The pattern may contain a suffix which is used to automatically
yading@10: determine the format of the image files to write.
yading@10: 
yading@10: For example the pattern "img-%03d.bmp" will specify a sequence of
yading@10: filenames of the form @file{img-001.bmp}, @file{img-002.bmp}, ...,
yading@10: @file{img-010.bmp}, etc.
yading@10: The pattern "img%%-%d.jpg" will specify a sequence of filenames of the
yading@10: form @file{img%-1.jpg}, @file{img%-2.jpg}, ..., @file{img%-10.jpg},
yading@10: etc.
yading@10: 
yading@10: The following example shows how to use @command{ffmpeg} for creating a
yading@10: sequence of files @file{img-001.jpeg}, @file{img-002.jpeg}, ...,
yading@10: taking one image every second from the input video:
yading@10: @example
yading@10: ffmpeg -i in.avi -vsync 1 -r 1 -f image2 'img-%03d.jpeg'
yading@10: @end example
yading@10: 
yading@10: Note that with @command{ffmpeg}, if the format is not specified with the
yading@10: @code{-f} option and the output filename specifies an image file
yading@10: format, the image2 muxer is automatically selected, so the previous
yading@10: command can be written as:
yading@10: @example
yading@10: ffmpeg -i in.avi -vsync 1 -r 1 'img-%03d.jpeg'
yading@10: @end example
yading@10: 
yading@10: Note also that the pattern must not necessarily contain "%d" or
yading@10: "%0@var{N}d", for example to create a single image file
yading@10: @file{img.jpeg} from the input video you can employ the command:
yading@10: @example
yading@10: ffmpeg -i in.avi -f image2 -frames:v 1 img.jpeg
yading@10: @end example
yading@10: 
yading@10: @table @option
yading@10: @item start_number @var{number}
yading@10: Start the sequence from @var{number}. Default value is 1. Must be a
yading@10: positive number.
yading@10: 
yading@10: @item -update @var{number}
yading@10: If @var{number} is nonzero, the filename will always be interpreted as just a
yading@10: filename, not a pattern, and this file will be continuously overwritten with new
yading@10: images.
yading@10: 
yading@10: @end table
yading@10: 
yading@10: The image muxer supports the .Y.U.V image file format. This format is
yading@10: special in that that each image frame consists of three files, for
yading@10: each of the YUV420P components. To read or write this image file format,
yading@10: specify the name of the '.Y' file. The muxer will automatically open the
yading@10: '.U' and '.V' files as required.
yading@10: 
yading@10: @anchor{md5}
yading@10: @section md5
yading@10: 
yading@10: MD5 testing format.
yading@10: 
yading@10: This muxer computes and prints the MD5 hash of all the input audio
yading@10: and video frames. By default audio frames are converted to signed
yading@10: 16-bit raw audio and video frames to raw video before computing the
yading@10: hash.
yading@10: 
yading@10: The output of the muxer consists of a single line of the form:
yading@10: MD5=@var{MD5}, where @var{MD5} is a hexadecimal number representing
yading@10: the computed MD5 hash.
yading@10: 
yading@10: For example to compute the MD5 hash of the input converted to raw
yading@10: audio and video, and store it in the file @file{out.md5}:
yading@10: @example
yading@10: ffmpeg -i INPUT -f md5 out.md5
yading@10: @end example
yading@10: 
yading@10: You can print the MD5 to stdout with the command:
yading@10: @example
yading@10: ffmpeg -i INPUT -f md5 -
yading@10: @end example
yading@10: 
yading@10: See also the @ref{framemd5} muxer.
yading@10: 
yading@10: @section MOV/MP4/ISMV
yading@10: 
yading@10: The mov/mp4/ismv muxer supports fragmentation. Normally, a MOV/MP4
yading@10: file has all the metadata about all packets stored in one location
yading@10: (written at the end of the file, it can be moved to the start for
yading@10: better playback by adding @var{faststart} to the @var{movflags}, or
yading@10: using the @command{qt-faststart} tool). A fragmented
yading@10: file consists of a number of fragments, where packets and metadata
yading@10: about these packets are stored together. Writing a fragmented
yading@10: file has the advantage that the file is decodable even if the
yading@10: writing is interrupted (while a normal MOV/MP4 is undecodable if
yading@10: it is not properly finished), and it requires less memory when writing
yading@10: very long files (since writing normal MOV/MP4 files stores info about
yading@10: every single packet in memory until the file is closed). The downside
yading@10: is that it is less compatible with other applications.
yading@10: 
yading@10: Fragmentation is enabled by setting one of the AVOptions that define
yading@10: how to cut the file into fragments:
yading@10: 
yading@10: @table @option
yading@10: @item -moov_size @var{bytes}
yading@10: Reserves space for the moov atom at the beginning of the file instead of placing the
yading@10: moov atom at the end. If the space reserved is insufficient, muxing will fail.
yading@10: @item -movflags frag_keyframe
yading@10: Start a new fragment at each video keyframe.
yading@10: @item -frag_duration @var{duration}
yading@10: Create fragments that are @var{duration} microseconds long.
yading@10: @item -frag_size @var{size}
yading@10: Create fragments that contain up to @var{size} bytes of payload data.
yading@10: @item -movflags frag_custom
yading@10: Allow the caller to manually choose when to cut fragments, by
yading@10: calling @code{av_write_frame(ctx, NULL)} to write a fragment with
yading@10: the packets written so far. (This is only useful with other
yading@10: applications integrating libavformat, not from @command{ffmpeg}.)
yading@10: @item -min_frag_duration @var{duration}
yading@10: Don't create fragments that are shorter than @var{duration} microseconds long.
yading@10: @end table
yading@10: 
yading@10: If more than one condition is specified, fragments are cut when
yading@10: one of the specified conditions is fulfilled. The exception to this is
yading@10: @code{-min_frag_duration}, which has to be fulfilled for any of the other
yading@10: conditions to apply.
yading@10: 
yading@10: Additionally, the way the output file is written can be adjusted
yading@10: through a few other options:
yading@10: 
yading@10: @table @option
yading@10: @item -movflags empty_moov
yading@10: Write an initial moov atom directly at the start of the file, without
yading@10: describing any samples in it. Generally, an mdat/moov pair is written
yading@10: at the start of the file, as a normal MOV/MP4 file, containing only
yading@10: a short portion of the file. With this option set, there is no initial
yading@10: mdat atom, and the moov atom only describes the tracks but has
yading@10: a zero duration.
yading@10: 
yading@10: Files written with this option set do not work in QuickTime.
yading@10: This option is implicitly set when writing ismv (Smooth Streaming) files.
yading@10: @item -movflags separate_moof
yading@10: Write a separate moof (movie fragment) atom for each track. Normally,
yading@10: packets for all tracks are written in a moof atom (which is slightly
yading@10: more efficient), but with this option set, the muxer writes one moof/mdat
yading@10: pair for each track, making it easier to separate tracks.
yading@10: 
yading@10: This option is implicitly set when writing ismv (Smooth Streaming) files.
yading@10: @item -movflags faststart
yading@10: Run a second pass moving the moov atom on top of the file. This
yading@10: operation can take a while, and will not work in various situations such
yading@10: as fragmented output, thus it is not enabled by default.
yading@10: @item -movflags rtphint
yading@10: Add RTP hinting tracks to the output file.
yading@10: @end table
yading@10: 
yading@10: Smooth Streaming content can be pushed in real time to a publishing
yading@10: point on IIS with this muxer. Example:
yading@10: @example
yading@10: ffmpeg -re @var{<normal input/transcoding options>} -movflags isml+frag_keyframe -f ismv http://server/publishingpoint.isml/Streams(Encoder1)
yading@10: @end example
yading@10: 
yading@10: @section mpegts
yading@10: 
yading@10: MPEG transport stream muxer.
yading@10: 
yading@10: This muxer implements ISO 13818-1 and part of ETSI EN 300 468.
yading@10: 
yading@10: The muxer options are:
yading@10: 
yading@10: @table @option
yading@10: @item -mpegts_original_network_id @var{number}
yading@10: Set the original_network_id (default 0x0001). This is unique identifier
yading@10: of a network in DVB. Its main use is in the unique identification of a
yading@10: service through the path Original_Network_ID, Transport_Stream_ID.
yading@10: @item -mpegts_transport_stream_id @var{number}
yading@10: Set the transport_stream_id (default 0x0001). This identifies a
yading@10: transponder in DVB.
yading@10: @item -mpegts_service_id @var{number}
yading@10: Set the service_id (default 0x0001) also known as program in DVB.
yading@10: @item -mpegts_pmt_start_pid @var{number}
yading@10: Set the first PID for PMT (default 0x1000, max 0x1f00).
yading@10: @item -mpegts_start_pid @var{number}
yading@10: Set the first PID for data packets (default 0x0100, max 0x0f00).
yading@10: @end table
yading@10: 
yading@10: The recognized metadata settings in mpegts muxer are @code{service_provider}
yading@10: and @code{service_name}. If they are not set the default for
yading@10: @code{service_provider} is "FFmpeg" and the default for
yading@10: @code{service_name} is "Service01".
yading@10: 
yading@10: @example
yading@10: ffmpeg -i file.mpg -c copy \
yading@10:      -mpegts_original_network_id 0x1122 \
yading@10:      -mpegts_transport_stream_id 0x3344 \
yading@10:      -mpegts_service_id 0x5566 \
yading@10:      -mpegts_pmt_start_pid 0x1500 \
yading@10:      -mpegts_start_pid 0x150 \
yading@10:      -metadata service_provider="Some provider" \
yading@10:      -metadata service_name="Some Channel" \
yading@10:      -y out.ts
yading@10: @end example
yading@10: 
yading@10: @section null
yading@10: 
yading@10: Null muxer.
yading@10: 
yading@10: This muxer does not generate any output file, it is mainly useful for
yading@10: testing or benchmarking purposes.
yading@10: 
yading@10: For example to benchmark decoding with @command{ffmpeg} you can use the
yading@10: command:
yading@10: @example
yading@10: ffmpeg -benchmark -i INPUT -f null out.null
yading@10: @end example
yading@10: 
yading@10: Note that the above command does not read or write the @file{out.null}
yading@10: file, but specifying the output file is required by the @command{ffmpeg}
yading@10: syntax.
yading@10: 
yading@10: Alternatively you can write the command as:
yading@10: @example
yading@10: ffmpeg -benchmark -i INPUT -f null -
yading@10: @end example
yading@10: 
yading@10: @section matroska
yading@10: 
yading@10: Matroska container muxer.
yading@10: 
yading@10: This muxer implements the matroska and webm container specs.
yading@10: 
yading@10: The recognized metadata settings in this muxer are:
yading@10: 
yading@10: @table @option
yading@10: 
yading@10: @item title=@var{title name}
yading@10: Name provided to a single track
yading@10: @end table
yading@10: 
yading@10: @table @option
yading@10: 
yading@10: @item language=@var{language name}
yading@10: Specifies the language of the track in the Matroska languages form
yading@10: @end table
yading@10: 
yading@10: @table @option
yading@10: 
yading@10: @item stereo_mode=@var{mode}
yading@10: Stereo 3D video layout of two views in a single video track
yading@10: @table @option
yading@10: @item mono
yading@10: video is not stereo
yading@10: @item left_right
yading@10: Both views are arranged side by side, Left-eye view is on the left
yading@10: @item bottom_top
yading@10: Both views are arranged in top-bottom orientation, Left-eye view is at bottom
yading@10: @item top_bottom
yading@10: Both views are arranged in top-bottom orientation, Left-eye view is on top
yading@10: @item checkerboard_rl
yading@10: Each view is arranged in a checkerboard interleaved pattern, Left-eye view being first
yading@10: @item checkerboard_lr
yading@10: Each view is arranged in a checkerboard interleaved pattern, Right-eye view being first
yading@10: @item row_interleaved_rl
yading@10: Each view is constituted by a row based interleaving, Right-eye view is first row
yading@10: @item row_interleaved_lr
yading@10: Each view is constituted by a row based interleaving, Left-eye view is first row
yading@10: @item col_interleaved_rl
yading@10: Both views are arranged in a column based interleaving manner, Right-eye view is first column
yading@10: @item col_interleaved_lr
yading@10: Both views are arranged in a column based interleaving manner, Left-eye view is first column
yading@10: @item anaglyph_cyan_red
yading@10: All frames are in anaglyph format viewable through red-cyan filters
yading@10: @item right_left
yading@10: Both views are arranged side by side, Right-eye view is on the left
yading@10: @item anaglyph_green_magenta
yading@10: All frames are in anaglyph format viewable through green-magenta filters
yading@10: @item block_lr
yading@10: Both eyes laced in one Block, Left-eye view is first
yading@10: @item block_rl
yading@10: Both eyes laced in one Block, Right-eye view is first
yading@10: @end table
yading@10: @end table
yading@10: 
yading@10: For example a 3D WebM clip can be created using the following command line:
yading@10: @example
yading@10: ffmpeg -i sample_left_right_clip.mpg -an -c:v libvpx -metadata stereo_mode=left_right -y stereo_clip.webm
yading@10: @end example
yading@10: 
yading@10: @section segment, stream_segment, ssegment
yading@10: 
yading@10: Basic stream segmenter.
yading@10: 
yading@10: The segmenter muxer outputs streams to a number of separate files of nearly
yading@10: fixed duration. Output filename pattern can be set in a fashion similar to
yading@10: @ref{image2}.
yading@10: 
yading@10: @code{stream_segment} is a variant of the muxer used to write to
yading@10: streaming output formats, i.e. which do not require global headers,
yading@10: and is recommended for outputting e.g. to MPEG transport stream segments.
yading@10: @code{ssegment} is a shorter alias for @code{stream_segment}.
yading@10: 
yading@10: Every segment starts with a keyframe of the selected reference stream,
yading@10: which is set through the @option{reference_stream} option.
yading@10: 
yading@10: Note that if you want accurate splitting for a video file, you need to
yading@10: make the input key frames correspond to the exact splitting times
yading@10: expected by the segmenter, or the segment muxer will start the new
yading@10: segment with the key frame found next after the specified start
yading@10: time.
yading@10: 
yading@10: The segment muxer works best with a single constant frame rate video.
yading@10: 
yading@10: Optionally it can generate a list of the created segments, by setting
yading@10: the option @var{segment_list}. The list type is specified by the
yading@10: @var{segment_list_type} option.
yading@10: 
yading@10: The segment muxer supports the following options:
yading@10: 
yading@10: @table @option
yading@10: @item reference_stream @var{specifier}
yading@10: Set the reference stream, as specified by the string @var{specifier}.
yading@10: If @var{specifier} is set to @code{auto}, the reference is choosen
yading@10: automatically. Otherwise it must be a stream specifier (see the ``Stream
yading@10: specifiers'' chapter in the ffmpeg manual) which specifies the
yading@10: reference stream. The default value is ``auto''.
yading@10: 
yading@10: @item segment_format @var{format}
yading@10: Override the inner container format, by default it is guessed by the filename
yading@10: extension.
yading@10: 
yading@10: @item segment_list @var{name}
yading@10: Generate also a listfile named @var{name}. If not specified no
yading@10: listfile is generated.
yading@10: 
yading@10: @item segment_list_flags @var{flags}
yading@10: Set flags affecting the segment list generation.
yading@10: 
yading@10: It currently supports the following flags:
yading@10: @table @var
yading@10: @item cache
yading@10: Allow caching (only affects M3U8 list files).
yading@10: 
yading@10: @item live
yading@10: Allow live-friendly file generation.
yading@10: @end table
yading@10: 
yading@10: Default value is @code{cache}.
yading@10: 
yading@10: @item segment_list_size @var{size}
yading@10: Update the list file so that it contains at most the last @var{size}
yading@10: segments. If 0 the list file will contain all the segments. Default
yading@10: value is 0.
yading@10: 
yading@10: @item segment_list type @var{type}
yading@10: Specify the format for the segment list file.
yading@10: 
yading@10: The following values are recognized:
yading@10: @table @option
yading@10: @item flat
yading@10: Generate a flat list for the created segments, one segment per line.
yading@10: 
yading@10: @item csv, ext
yading@10: Generate a list for the created segments, one segment per line,
yading@10: each line matching the format (comma-separated values):
yading@10: @example
yading@10: @var{segment_filename},@var{segment_start_time},@var{segment_end_time}
yading@10: @end example
yading@10: 
yading@10: @var{segment_filename} is the name of the output file generated by the
yading@10: muxer according to the provided pattern. CSV escaping (according to
yading@10: RFC4180) is applied if required.
yading@10: 
yading@10: @var{segment_start_time} and @var{segment_end_time} specify
yading@10: the segment start and end time expressed in seconds.
yading@10: 
yading@10: A list file with the suffix @code{".csv"} or @code{".ext"} will
yading@10: auto-select this format.
yading@10: 
yading@10: @code{ext} is deprecated in favor or @code{csv}.
yading@10: 
yading@10: @item ffconcat
yading@10: Generate an ffconcat file for the created segments. The resulting file
yading@10: can be read using the FFmpeg @ref{concat} demuxer.
yading@10: 
yading@10: A list file with the suffix @code{".ffcat"} or @code{".ffconcat"} will
yading@10: auto-select this format.
yading@10: 
yading@10: @item m3u8
yading@10: Generate an extended M3U8 file, version 3, compliant with
yading@10: @url{http://tools.ietf.org/id/draft-pantos-http-live-streaming}.
yading@10: 
yading@10: A list file with the suffix @code{".m3u8"} will auto-select this format.
yading@10: @end table
yading@10: 
yading@10: If not specified the type is guessed from the list file name suffix.
yading@10: 
yading@10: @item segment_time @var{time}
yading@10: Set segment duration to @var{time}, the value must be a duration
yading@10: specification. Default value is "2". See also the
yading@10: @option{segment_times} option.
yading@10: 
yading@10: Note that splitting may not be accurate, unless you force the
yading@10: reference stream key-frames at the given time. See the introductory
yading@10: notice and the examples below.
yading@10: 
yading@10: @item segment_time_delta @var{delta}
yading@10: Specify the accuracy time when selecting the start time for a
yading@10: segment, expressed as a duration specification. Default value is "0".
yading@10: 
yading@10: When delta is specified a key-frame will start a new segment if its
yading@10: PTS satisfies the relation:
yading@10: @example
yading@10: PTS >= start_time - time_delta
yading@10: @end example
yading@10: 
yading@10: This option is useful when splitting video content, which is always
yading@10: split at GOP boundaries, in case a key frame is found just before the
yading@10: specified split time.
yading@10: 
yading@10: In particular may be used in combination with the @file{ffmpeg} option
yading@10: @var{force_key_frames}. The key frame times specified by
yading@10: @var{force_key_frames} may not be set accurately because of rounding
yading@10: issues, with the consequence that a key frame time may result set just
yading@10: before the specified time. For constant frame rate videos a value of
yading@10: 1/2*@var{frame_rate} should address the worst case mismatch between
yading@10: the specified time and the time set by @var{force_key_frames}.
yading@10: 
yading@10: @item segment_times @var{times}
yading@10: Specify a list of split points. @var{times} contains a list of comma
yading@10: separated duration specifications, in increasing order. See also
yading@10: the @option{segment_time} option.
yading@10: 
yading@10: @item segment_frames @var{frames}
yading@10: Specify a list of split video frame numbers. @var{frames} contains a
yading@10: list of comma separated integer numbers, in increasing order.
yading@10: 
yading@10: This option specifies to start a new segment whenever a reference
yading@10: stream key frame is found and the sequential number (starting from 0)
yading@10: of the frame is greater or equal to the next value in the list.
yading@10: 
yading@10: @item segment_wrap @var{limit}
yading@10: Wrap around segment index once it reaches @var{limit}.
yading@10: 
yading@10: @item segment_start_number @var{number}
yading@10: Set the sequence number of the first segment. Defaults to @code{0}.
yading@10: 
yading@10: @item reset_timestamps @var{1|0}
yading@10: Reset timestamps at the begin of each segment, so that each segment
yading@10: will start with near-zero timestamps. It is meant to ease the playback
yading@10: of the generated segments. May not work with some combinations of
yading@10: muxers/codecs. It is set to @code{0} by default.
yading@10: @end table
yading@10: 
yading@10: @subsection Examples
yading@10: 
yading@10: @itemize
yading@10: @item
yading@10: To remux the content of file @file{in.mkv} to a list of segments
yading@10: @file{out-000.nut}, @file{out-001.nut}, etc., and write the list of
yading@10: generated segments to @file{out.list}:
yading@10: @example
yading@10: ffmpeg -i in.mkv -codec copy -map 0 -f segment -segment_list out.list out%03d.nut
yading@10: @end example
yading@10: 
yading@10: @item
yading@10: As the example above, but segment the input file according to the split
yading@10: points specified by the @var{segment_times} option:
yading@10: @example
yading@10: 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
yading@10: @end example
yading@10: 
yading@10: @item
yading@10: As the example above, but use the @code{ffmpeg} @var{force_key_frames}
yading@10: option to force key frames in the input at the specified location, together
yading@10: with the segment option @var{segment_time_delta} to account for
yading@10: possible roundings operated when setting key frame times.
yading@10: @example
yading@10: ffmpeg -i in.mkv -force_key_frames 1,2,3,5,8,13,21 -codec:v mpeg4 -codec:a pcm_s16le -map 0 \
yading@10: -f segment -segment_list out.csv -segment_times 1,2,3,5,8,13,21 -segment_time_delta 0.05 out%03d.nut
yading@10: @end example
yading@10: In order to force key frames on the input file, transcoding is
yading@10: required.
yading@10: 
yading@10: @item
yading@10: Segment the input file by splitting the input file according to the
yading@10: frame numbers sequence specified with the @var{segment_frames} option:
yading@10: @example
yading@10: ffmpeg -i in.mkv -codec copy -map 0 -f segment -segment_list out.csv -segment_frames 100,200,300,500,800 out%03d.nut
yading@10: @end example
yading@10: 
yading@10: @item
yading@10: To convert the @file{in.mkv} to TS segments using the @code{libx264}
yading@10: and @code{libfaac} encoders:
yading@10: @example
yading@10: ffmpeg -i in.mkv -map 0 -codec:v libx264 -codec:a libfaac -f ssegment -segment_list out.list out%03d.ts
yading@10: @end example
yading@10: 
yading@10: @item
yading@10: Segment the input file, and create an M3U8 live playlist (can be used
yading@10: as live HLS source):
yading@10: @example
yading@10: ffmpeg -re -i in.mkv -codec copy -map 0 -f segment -segment_list playlist.m3u8 \
yading@10: -segment_list_flags +live -segment_time 10 out%03d.mkv
yading@10: @end example
yading@10: @end itemize
yading@10: 
yading@10: @section mp3
yading@10: 
yading@10: The MP3 muxer writes a raw MP3 stream with an ID3v2 header at the beginning and
yading@10: optionally an ID3v1 tag at the end. ID3v2.3 and ID3v2.4 are supported, the
yading@10: @code{id3v2_version} option controls which one is used. The legacy ID3v1 tag is
yading@10: not written by default, but may be enabled with the @code{write_id3v1} option.
yading@10: 
yading@10: For seekable output the muxer also writes a Xing frame at the beginning, which
yading@10: contains the number of frames in the file. It is useful for computing duration
yading@10: of VBR files.
yading@10: 
yading@10: The muxer supports writing ID3v2 attached pictures (APIC frames). The pictures
yading@10: are supplied to the muxer in form of a video stream with a single packet. There
yading@10: can be any number of those streams, each will correspond to a single APIC frame.
yading@10: The stream metadata tags @var{title} and @var{comment} map to APIC
yading@10: @var{description} and @var{picture type} respectively. See
yading@10: @url{http://id3.org/id3v2.4.0-frames} for allowed picture types.
yading@10: 
yading@10: Note that the APIC frames must be written at the beginning, so the muxer will
yading@10: buffer the audio frames until it gets all the pictures. It is therefore advised
yading@10: to provide the pictures as soon as possible to avoid excessive buffering.
yading@10: 
yading@10: Examples:
yading@10: 
yading@10: Write an mp3 with an ID3v2.3 header and an ID3v1 footer:
yading@10: @example
yading@10: ffmpeg -i INPUT -id3v2_version 3 -write_id3v1 1 out.mp3
yading@10: @end example
yading@10: 
yading@10: To attach a picture to an mp3 file select both the audio and the picture stream
yading@10: with @code{map}:
yading@10: @example
yading@10: ffmpeg -i input.mp3 -i cover.png -c copy -map 0 -map 1
yading@10: -metadata:s:v title="Album cover" -metadata:s:v comment="Cover (Front)" out.mp3
yading@10: @end example
yading@10: 
yading@10: @section ogg
yading@10: 
yading@10: Ogg container muxer.
yading@10: 
yading@10: @table @option
yading@10: @item -page_duration @var{duration}
yading@10: Preferred page duration, in microseconds. The muxer will attempt to create
yading@10: pages that are approximately @var{duration} microseconds long. This allows the
yading@10: user to compromise between seek granularity and container overhead. The default
yading@10: is 1 second. A value of 0 will fill all segments, making pages as large as
yading@10: possible. A value of 1 will effectively use 1 packet-per-page in most
yading@10: situations, giving a small seek granularity at the cost of additional container
yading@10: overhead.
yading@10: @end table
yading@10: 
yading@10: @section tee
yading@10: 
yading@10: The tee muxer can be used to write the same data to several files or any
yading@10: other kind of muxer. It can be used, for example, to both stream a video to
yading@10: the network and save it to disk at the same time.
yading@10: 
yading@10: It is different from specifying several outputs to the @command{ffmpeg}
yading@10: command-line tool because the audio and video data will be encoded only once
yading@10: with the tee muxer; encoding can be a very expensive process. It is not
yading@10: useful when using the libavformat API directly because it is then possible
yading@10: to feed the same packets to several muxers directly.
yading@10: 
yading@10: The slave outputs are specified in the file name given to the muxer,
yading@10: separated by '|'. If any of the slave name contains the '|' separator,
yading@10: leading or trailing spaces or any special character, it must be
yading@10: escaped (see the ``Quoting and escaping'' section in the ffmpeg-utils
yading@10: manual).
yading@10: 
yading@10: Options can be specified for each slave by prepending them as a list of
yading@10: @var{key}=@var{value} pairs separated by ':', between square brackets. If
yading@10: the options values contain a special character or the ':' separator, they
yading@10: must be escaped; note that this is a second level escaping.
yading@10: 
yading@10: Example: encode something and both archive it in a WebM file and stream it
yading@10: as MPEG-TS over UDP (the streams need to be explicitly mapped):
yading@10: 
yading@10: @example
yading@10: ffmpeg -i ... -c:v libx264 -c:a mp2 -f tee -map 0:v -map 0:a
yading@10:   "archive-20121107.mkv|[f=mpegts]udp://10.0.1.255:1234/"
yading@10: @end example
yading@10: 
yading@10: Note: some codecs may need different options depending on the output format;
yading@10: the auto-detection of this can not work with the tee muxer. The main example
yading@10: is the @option{global_header} flag.
yading@10: 
yading@10: @c man end MUXERS