mirror of https://git.ffmpeg.org/ffmpeg.git
303 lines
9.8 KiB
Plaintext
303 lines
9.8 KiB
Plaintext
@chapter Muxers
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@c man begin MUXERS
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Muxers are configured elements in Libav which allow writing
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multimedia streams to a particular type of file.
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When you configure your Libav build, all the supported muxers
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are enabled by default. You can list all available muxers using the
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configure option @code{--list-muxers}.
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You can disable all the muxers with the configure option
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@code{--disable-muxers} and selectively enable / disable single muxers
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with the options @code{--enable-muxer=@var{MUXER}} /
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@code{--disable-muxer=@var{MUXER}}.
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The option @code{-formats} of the av* tools will display the list of
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enabled muxers.
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A description of some of the currently available muxers follows.
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@anchor{crc}
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@section crc
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CRC (Cyclic Redundancy Check) testing format.
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This muxer computes and prints the Adler-32 CRC of all the input audio
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and video frames. By default audio frames are converted to signed
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16-bit raw audio and video frames to raw video before computing the
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CRC.
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The output of the muxer consists of a single line of the form:
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CRC=0x@var{CRC}, where @var{CRC} is a hexadecimal number 0-padded to
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8 digits containing the CRC for all the decoded input frames.
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For example to compute the CRC of the input, and store it in the file
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@file{out.crc}:
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@example
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avconv -i INPUT -f crc out.crc
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@end example
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You can print the CRC to stdout with the command:
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@example
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avconv -i INPUT -f crc -
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@end example
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You can select the output format of each frame with @command{avconv} by
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specifying the audio and video codec and format. For example to
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compute the CRC of the input audio converted to PCM unsigned 8-bit
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and the input video converted to MPEG-2 video, use the command:
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@example
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avconv -i INPUT -c:a pcm_u8 -c:v mpeg2video -f crc -
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@end example
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See also the @ref{framecrc} muxer.
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@anchor{framecrc}
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@section framecrc
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Per-frame CRC (Cyclic Redundancy Check) testing format.
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This muxer computes and prints the Adler-32 CRC for each decoded audio
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and video frame. By default audio frames are converted to signed
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16-bit raw audio and video frames to raw video before computing the
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CRC.
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The output of the muxer consists of a line for each audio and video
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frame of the form: @var{stream_index}, @var{frame_dts},
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@var{frame_size}, 0x@var{CRC}, where @var{CRC} is a hexadecimal
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number 0-padded to 8 digits containing the CRC of the decoded frame.
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For example to compute the CRC of each decoded frame in the input, and
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store it in the file @file{out.crc}:
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@example
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avconv -i INPUT -f framecrc out.crc
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@end example
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You can print the CRC of each decoded frame to stdout with the command:
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@example
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avconv -i INPUT -f framecrc -
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@end example
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You can select the output format of each frame with @command{avconv} by
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specifying the audio and video codec and format. For example, to
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compute the CRC of each decoded input audio frame converted to PCM
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unsigned 8-bit and of each decoded input video frame converted to
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MPEG-2 video, use the command:
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@example
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avconv -i INPUT -c:a pcm_u8 -c:v mpeg2video -f framecrc -
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@end example
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See also the @ref{crc} muxer.
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@anchor{image2}
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@section image2
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Image file muxer.
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The image file muxer writes video frames to image files.
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The output filenames are specified by a pattern, which can be used to
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produce sequentially numbered series of files.
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The pattern may contain the string "%d" or "%0@var{N}d", this string
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specifies the position of the characters representing a numbering in
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the filenames. If the form "%0@var{N}d" is used, the string
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representing the number in each filename is 0-padded to @var{N}
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digits. The literal character '%' can be specified in the pattern with
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the string "%%".
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If the pattern contains "%d" or "%0@var{N}d", the first filename of
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the file list specified will contain the number 1, all the following
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numbers will be sequential.
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The pattern may contain a suffix which is used to automatically
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determine the format of the image files to write.
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For example the pattern "img-%03d.bmp" will specify a sequence of
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filenames of the form @file{img-001.bmp}, @file{img-002.bmp}, ...,
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@file{img-010.bmp}, etc.
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The pattern "img%%-%d.jpg" will specify a sequence of filenames of the
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form @file{img%-1.jpg}, @file{img%-2.jpg}, ..., @file{img%-10.jpg},
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etc.
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The following example shows how to use @command{avconv} for creating a
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sequence of files @file{img-001.jpeg}, @file{img-002.jpeg}, ...,
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taking one image every second from the input video:
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@example
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avconv -i in.avi -vsync 1 -r 1 -f image2 'img-%03d.jpeg'
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@end example
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Note that with @command{avconv}, if the format is not specified with the
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@code{-f} option and the output filename specifies an image file
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format, the image2 muxer is automatically selected, so the previous
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command can be written as:
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@example
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avconv -i in.avi -vsync 1 -r 1 'img-%03d.jpeg'
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@end example
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Note also that the pattern must not necessarily contain "%d" or
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"%0@var{N}d", for example to create a single image file
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@file{img.jpeg} from the input video you can employ the command:
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@example
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avconv -i in.avi -f image2 -frames:v 1 img.jpeg
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@end example
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@section mpegts
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MPEG transport stream muxer.
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This muxer implements ISO 13818-1 and part of ETSI EN 300 468.
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The muxer options are:
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@table @option
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@item -mpegts_original_network_id @var{number}
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Set the original_network_id (default 0x0001). This is unique identifier
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of a network in DVB. Its main use is in the unique identification of a
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service through the path Original_Network_ID, Transport_Stream_ID.
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@item -mpegts_transport_stream_id @var{number}
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Set the transport_stream_id (default 0x0001). This identifies a
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transponder in DVB.
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@item -mpegts_service_id @var{number}
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Set the service_id (default 0x0001) also known as program in DVB.
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@item -mpegts_pmt_start_pid @var{number}
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Set the first PID for PMT (default 0x1000, max 0x1f00).
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@item -mpegts_start_pid @var{number}
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Set the first PID for data packets (default 0x0100, max 0x0f00).
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@end table
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The recognized metadata settings in mpegts muxer are @code{service_provider}
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and @code{service_name}. If they are not set the default for
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@code{service_provider} is "Libav" and the default for
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@code{service_name} is "Service01".
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@example
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avconv -i file.mpg -c copy \
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-mpegts_original_network_id 0x1122 \
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-mpegts_transport_stream_id 0x3344 \
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-mpegts_service_id 0x5566 \
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-mpegts_pmt_start_pid 0x1500 \
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-mpegts_start_pid 0x150 \
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-metadata service_provider="Some provider" \
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-metadata service_name="Some Channel" \
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-y out.ts
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@end example
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@section null
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Null muxer.
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This muxer does not generate any output file, it is mainly useful for
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testing or benchmarking purposes.
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For example to benchmark decoding with @command{avconv} you can use the
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command:
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@example
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avconv -benchmark -i INPUT -f null out.null
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@end example
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Note that the above command does not read or write the @file{out.null}
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file, but specifying the output file is required by the @command{avconv}
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syntax.
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Alternatively you can write the command as:
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@example
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avconv -benchmark -i INPUT -f null -
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@end example
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@section matroska
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Matroska container muxer.
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This muxer implements the matroska and webm container specs.
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The recognized metadata settings in this muxer are:
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@table @option
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@item title=@var{title name}
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Name provided to a single track
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@end table
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@table @option
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@item language=@var{language name}
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Specifies the language of the track in the Matroska languages form
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@end table
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@table @option
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@item STEREO_MODE=@var{mode}
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Stereo 3D video layout of two views in a single video track
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@table @option
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@item mono
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video is not stereo
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@item left_right
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Both views are arranged side by side, Left-eye view is on the left
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@item bottom_top
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Both views are arranged in top-bottom orientation, Left-eye view is at bottom
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@item top_bottom
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Both views are arranged in top-bottom orientation, Left-eye view is on top
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@item checkerboard_rl
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Each view is arranged in a checkerboard interleaved pattern, Left-eye view being first
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@item checkerboard_lr
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Each view is arranged in a checkerboard interleaved pattern, Right-eye view being first
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@item row_interleaved_rl
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Each view is constituted by a row based interleaving, Right-eye view is first row
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@item row_interleaved_lr
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Each view is constituted by a row based interleaving, Left-eye view is first row
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@item col_interleaved_rl
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Both views are arranged in a column based interleaving manner, Right-eye view is first column
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@item col_interleaved_lr
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Both views are arranged in a column based interleaving manner, Left-eye view is first column
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@item anaglyph_cyan_red
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All frames are in anaglyph format viewable through red-cyan filters
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@item right_left
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Both views are arranged side by side, Right-eye view is on the left
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@item anaglyph_green_magenta
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All frames are in anaglyph format viewable through green-magenta filters
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@item block_lr
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Both eyes laced in one Block, Left-eye view is first
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@item block_rl
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Both eyes laced in one Block, Right-eye view is first
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@end table
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@end table
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For example a 3D WebM clip can be created using the following command line:
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@example
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avconv -i sample_left_right_clip.mpg -an -c:v libvpx -metadata STEREO_MODE=left_right -y stereo_clip.webm
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@end example
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@section segment
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Basic stream segmenter.
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The segmenter muxer outputs streams to a number of separate files of nearly
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fixed duration. Output filename pattern can be set in a fashion similar to
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@ref{image2}.
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Every segment starts with a video keyframe, if a video stream is present.
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The segment muxer works best with a single constant frame rate video.
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Optionally it can generate a flat list of the created segments, one segment
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per line.
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@table @option
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@item segment_format @var{format}
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Override the inner container format, by default it is guessed by the filename
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extension.
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@item segment_time @var{t}
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Set segment duration to @var{t} seconds.
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@item segment_list @var{name}
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Generate also a listfile named @var{name}.
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@item segment_list_size @var{size}
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Overwrite the listfile once it reaches @var{size} entries.
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@end table
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@example
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avconv -i in.mkv -c copy -map 0 -f segment -list out.list out%03d.nut
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@end example
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@c man end MUXERS
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