@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}.
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.
+
+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.
+
+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{hls}
@section hls
a .ts extension.
@example
-avconv -i in.nut out.m3u8
+ffmpeg -i in.nut out.m3u8
@end example
@table @option
Start the sequence from @var{number}.
@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
+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
Start the sequence from @var{number}.
@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.
+
+@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
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
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
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 moov atom on top 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.
@end table
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 mpegts
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_provider} is "FFmpeg" and the default for
@code{service_name} is "Service01".
@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 matroska
@table @option
-@item STEREO_MODE=@var{mode}
+@item stereo_mode=@var{mode}
Stereo 3D video layout of two views in a single video track
@table @option
@item mono
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
-@section segment
+@section segment, stream_segment, ssegment
Basic stream segmenter.
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 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 choosen
+automatically. Otherwise it must be a stream specifier (see the ``Stream
+specifiers'' chapter in the ffmpeg manual) which specifies the
+reference stream. The default value is ``auto''.
+
@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_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 @var
+@item cache
+Allow caching (only affects M3U8 list files).
+
+@item live
+Allow live-friendly file generation.
+
+This currently only affects M3U8 lists. In particular, write a fake
+EXT-X-TARGETDURATION duration field at the top of the file, based on
+the specified @var{segment_time}.
+@end table
+
+Default value is @code{cache}.
+
@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 the last @var{size}
+segments. If 0 the list file will contain all the segments. Default
+value is 0.
+
+@item segment_list type @var{type}
+Specify the format for the segment list file.
+
+The following values are recognized:
+@table @option
+@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.
+
+@code{ext} is deprecated in favor or @code{csv}.
+
+@item m3u8
+Generate an extended M3U8 file, version 4, compliant with
+@url{http://tools.ietf.org/id/draft-pantos-http-live-streaming-08.txt}.
+
+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}. Default value is "2".
+
+@item segment_time_delta @var{delta}
+Specify the accuracy time when selecting the start time for a
+segment. 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.
+
+@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.
@end table
+@section Examples
+
+@itemize
+@item
+To 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
+As the example above, but 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
+As the example above, but use the @code{ffmpeg} @var{force_key_frames}
+option to force key frames in the input at the specified location, together
+with the segment option @var{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 @var{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
+To 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
-avconv -i in.mkv -c copy -map 0 -f segment -list out.list out%03d.nut
+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 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:
@example
-avconv -i input.mp3 -i cover.png -c copy -metadata:s:v title="Album cover"
+ffmpeg -i input.mp3 -i cover.png -c copy -metadata:s:v title="Album cover"
-metadata:s:v comment="Cover (Front)" out.mp3
@end example
projects / ffmpeg / blobdiff