@chapter Muxers
@c man begin MUXERS
-Muxers are configured elements in Libav which allow writing
+Muxers are configured elements in FFmpeg which allow writing
multimedia streams to a particular type of file.
-When you configure your Libav build, all the supported muxers
+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}.
with the options @code{--enable-muxer=@var{MUXER}} /
@code{--disable-muxer=@var{MUXER}}.
-The option @code{-formats} of the av* tools will display the list of
+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=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
-avconv -i INPUT -f crc out.crc
+ffmpeg -i INPUT -f crc out.crc
@end example
You can print the CRC to stdout with the command:
@example
-avconv -i INPUT -f crc -
+ffmpeg -i INPUT -f crc -
@end example
-You can select the output format of each frame with @command{avconv} by
+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
-avconv -i INPUT -c:a pcm_u8 -c:v mpeg2video -f crc -
+ffmpeg -i INPUT -c:a pcm_u8 -c:v mpeg2video -f crc -
@end example
-See also the @ref{framecrc} muxer.
-
@anchor{framecrc}
@section framecrc
-Per-frame CRC (Cyclic Redundancy Check) testing format.
+Per-packet CRC (Cyclic Redundancy Check) testing format.
-This muxer computes and prints the Adler-32 CRC for each decoded audio
-and video frame. By default audio frames are converted to signed
+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
-frame of the form: @var{stream_index}, @var{frame_dts},
-@var{frame_size}, 0x@var{CRC}, where @var{CRC} is a hexadecimal
-number 0-padded to 8 digits containing the CRC of the decoded frame.
+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
-For example to compute the CRC of each decoded frame in the input, and
-store it in the file @file{out.crc}:
+@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
-avconv -i INPUT -f framecrc out.crc
+ffmpeg -i INPUT -f framecrc out.crc
@end example
-You can print the CRC of each decoded frame to stdout with the command:
+To print the information to stdout, use the command:
@example
-avconv -i INPUT -f framecrc -
+ffmpeg -i INPUT -f framecrc -
@end example
-You can select the output format of each frame with @command{avconv} by
-specifying the audio and video codec and format. For example, to
+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
-avconv -i INPUT -c:a pcm_u8 -c:v mpeg2video -f framecrc -
+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 specification.
+the HTTP Live Streaming (HLS) specification.
+
+It creates a playlist file, and one or more segment files. The output filename
+specifies the playlist filename.
-It creates a playlist file and numbered segment files. The output
-filename specifies the playlist filename; the segment filenames
-receive the same basename as the playlist, a sequential number and
-a .ts extension.
+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
-avconv -i in.nut out.m3u8
+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.
-@item -hls_list_size @var{size}
-Set the maximum number of playlist entries.
-@item -hls_wrap @var{wrap}
-Set the number after which index wraps.
-@item -start_number @var{number}
-Start the sequence from @var{number}.
-@item -hls_base_url @var{baseurl}
+@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.
-@item -hls_allow_cache @var{allowcache}
-Explicitly set whether the client MAY (1) or MUST NOT (0) cache media segments
+
+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_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}.
@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
form @file{img%-1.jpg}, @file{img%-2.jpg}, ..., @file{img%-10.jpg},
etc.
-The following example shows how to use @command{avconv} for creating a
+@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
-avconv -i in.avi -vsync 1 -r 1 -f image2 'img-%03d.jpeg'
+ffmpeg -i in.avi -vsync 1 -r 1 -f image2 'img-%03d.jpeg'
@end example
-Note that with @command{avconv}, if the format is not specified with the
+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
-avconv -i in.avi -vsync 1 -r 1 'img-%03d.jpeg'
+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
-avconv -i in.avi -f image2 -frames:v 1 img.jpeg
+ffmpeg -i in.avi -f image2 -frames:v 1 img.jpeg
@end example
-@table @option
-@item -start_number @var{number}
-Start the sequence from @var{number}.
+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.
-@item -update @var{number}
-If @var{number} is nonzero, the filename will always be interpreted as just a
-filename, not a pattern, and this file will be continuously overwritten with new
-images.
+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 1. Must
+be a non-negative number.
+
+@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 title=@var{title name}
-Name provided to a single track
-@end table
+@item language
+Specify the language of the track in the Matroska languages form.
-@table @option
+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 language=@var{language name}
-Specifies the language of the track in the Matroska languages form
-@end table
-
-@table @option
+@item stereo_mode
+Set stereo 3D video layout of two views in a single video track.
-@item STEREO_MODE=@var{mode}
-Stereo 3D video layout of two views in a single video track
-@table @option
+The following values are recognized:
+@table @samp
@item mono
video is not stereo
@item left_right
For example a 3D WebM clip can be created using the following command line:
@example
-avconv -i sample_left_right_clip.mpg -an -c:v libvpx -metadata STEREO_MODE=left_right -y stereo_clip.webm
+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
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 using the @command{qt-faststart} tool). A fragmented
+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
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}
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{avconv}.)
+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
mdat atom, and the moov atom only describes the tracks but has
a zero duration.
-Files written with this option set do not work in QuickTime.
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,
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.
+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.
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
-avconv -re @var{<normal input/transcoding options>} -movflags isml+frag_keyframe -f ismv http://server/publishingpoint.isml/Streams(Encoder1)
+ffmpeg -re @var{<normal input/transcoding options>} -movflags isml+frag_keyframe -f ismv http://server/publishingpoint.isml/Streams(Encoder1)
@end example
@section mp3
Write an mp3 with an ID3v2.3 header and an ID3v1 footer:
@example
-avconv -i INPUT -id3v2_version 3 -write_id3v1 1 out.mp3
+ffmpeg -i INPUT -id3v2_version 3 -write_id3v1 1 out.mp3
@end example
-Attach a picture to an mp3:
+To attach a picture to an mp3 file select both the audio and the picture stream
+with @code{map}:
@example
-avconv -i input.mp3 -i cover.png -c copy -metadata:s:v title="Album cover"
--metadata:s:v comment="Cover (Front)" out.mp3
+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
-avconv -i input.wav -write_xing 0 -id3v2_version 0 out.mp3
+ffmpeg -i input.wav -write_xing 0 -id3v2_version 0 out.mp3
@end example
@section mpegts
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
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
-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 "Libav" and the default for
-@code{service_name} is "Service01".
+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
-avconv -i file.mpg -c copy \
+ffmpeg -i file.mpg -c copy \
-mpegts_original_network_id 0x1122 \
-mpegts_transport_stream_id 0x3344 \
-mpegts_service_id 0x5566 \
This muxer does not generate any output file, it is mainly useful for
testing or benchmarking purposes.
-For example to benchmark decoding with @command{avconv} you can use the
+For example to benchmark decoding with @command{ffmpeg} you can use the
command:
@example
-avconv -benchmark -i INPUT -f null out.null
+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{avconv}
+file, but specifying the output file is required by the @command{ffmpeg}
syntax.
Alternatively you can write the command as:
@example
-avconv -benchmark -i INPUT -f null -
+ffmpeg -benchmark -i INPUT -f null -
@end example
@section 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 wihout 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
-avconv -i INPUT -f_strict experimental -syncpoints none - | processor
+ffmpeg -i INPUT -f_strict experimental -syncpoints none - | processor
@end example
@section ogg
overhead.
@end table
-@section segment
+@anchor{segment}
+@section segment, stream_segment, ssegment
Basic stream segmenter.
-The segmenter muxer outputs streams to a number of separate files of nearly
+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}.
-Every segment starts with a video keyframe, if a video stream is present.
+@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 flat list of the created segments, one segment
-per line.
+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_time @var{t}
-Set segment duration to @var{t} seconds.
+
+@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}.
+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}
-Overwrite the listfile once it reaches @var{size} entries.
+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 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.
+
+@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.
@end table
+@subsection Example
@example
-avconv -i in.mkv -c copy -map 0 -f segment -list out.list out%03d.nut
+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
@c man end MUXERS
projects / ffmpeg / blobdiff