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\input texinfo @c -*- texinfo -*-
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@settitle FFmpeg Documentation
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@titlepage
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@sp 7
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@center @titlefont{FFmpeg Documentation}
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@sp 3
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@end titlepage
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@chapter Introduction
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FFmpeg is a very fast video and audio converter. It can also grab from
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a live audio/video source.
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The command line interface is designed to be intuitive, in the sense
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that FFmpeg tries to figure out all parameters that can possibly be
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derived automatically. You usually only have to specify the target
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bitrate you want.
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FFmpeg can also convert from any sample rate to any other, and resize
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video on the fly with a high quality polyphase filter.
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@chapter Quick Start
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@c man begin EXAMPLES
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@section Video and Audio grabbing
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FFmpeg can use a video4linux compatible video source and any Open Sound
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System audio source:
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@example
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ffmpeg /tmp/out.mpg
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@end example
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Note that you must activate the right video source and channel before
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launching FFmpeg with any TV viewer such as xawtv
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(@url{http://bytesex.org/xawtv/}) by Gerd Knorr. You also
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have to set the audio recording levels correctly with a
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standard mixer.
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@section Video and Audio file format conversion
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* FFmpeg can use any supported file format and protocol as input:
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Examples:
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* You can use YUV files as input:
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@example
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ffmpeg -i /tmp/test%d.Y /tmp/out.mpg
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@end example
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It will use the files:
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@example
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/tmp/test0.Y, /tmp/test0.U, /tmp/test0.V,
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/tmp/test1.Y, /tmp/test1.U, /tmp/test1.V, etc...
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@end example
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The Y files use twice the resolution of the U and V files. They are
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raw files, without header. They can be generated by all decent video
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decoders. You must specify the size of the image with the @option{-s} option
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if FFmpeg cannot guess it.
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* You can input from a raw YUV420P file:
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@example
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ffmpeg -i /tmp/test.yuv /tmp/out.avi
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@end example
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test.yuv is a file containing raw YUV planar data. Each frame is composed
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of the Y plane followed by the U and V planes at half vertical and
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horizontal resolution.
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* You can output to a raw YUV420P file:
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@example
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ffmpeg -i mydivx.avi hugefile.yuv
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@end example
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* You can set several input files and output files:
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@example
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ffmpeg -i /tmp/a.wav -s 640x480 -i /tmp/a.yuv /tmp/a.mpg
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@end example
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Converts the audio file a.wav and the raw YUV video file a.yuv
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to MPEG file a.mpg.
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* You can also do audio and video conversions at the same time:
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@example
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ffmpeg -i /tmp/a.wav -ar 22050 /tmp/a.mp2
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@end example
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Converts a.wav to MPEG audio at 22050Hz sample rate.
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* You can encode to several formats at the same time and define a
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mapping from input stream to output streams:
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@example
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ffmpeg -i /tmp/a.wav -ab 64 /tmp/a.mp2 -ab 128 /tmp/b.mp2 -map 0:0 -map 0:0
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@end example
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Converts a.wav to a.mp2 at 64 kbits and to b.mp2 at 128 kbits. '-map
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file:index' specifies which input stream is used for each output
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stream, in the order of the definition of output streams.
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* You can transcode decrypted VOBs
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@example
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ffmpeg -i snatch_1.vob -f avi -vcodec mpeg4 -b 800k -g 300 -bf 2 -acodec mp3 -ab 128 snatch.avi
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@end example
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This is a typical DVD ripping example; the input is a VOB file, the
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output an AVI file with MPEG-4 video and MP3 audio. Note that in this
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command we use B-frames so the MPEG-4 stream is DivX5 compatible, and
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GOP size is 300 which means one intra frame every 10 seconds for 29.97fps
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input video. Furthermore, the audio stream is MP3-encoded so you need
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to enable LAME support by passing @code{--enable-mp3lame} to configure.
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The mapping is particularly useful for DVD transcoding
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to get the desired audio language.
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NOTE: To see the supported input formats, use @code{ffmpeg -formats}.
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@c man end
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@chapter Invocation
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@section Syntax
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The generic syntax is:
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@example
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@c man begin SYNOPSIS
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ffmpeg [[infile options][@option{-i} @var{infile}]]... @{[outfile options] @var{outfile}@}...
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@c man end
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@end example
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@c man begin DESCRIPTION
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If no input file is given, audio/video grabbing is done.
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As a general rule, options are applied to the next specified
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file. For example, if you give the @option{-b 64k} option, it sets the video
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bitrate of the next file. The format option may be needed for raw input
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files.
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By default, FFmpeg tries to convert as losslessly as possible: It
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uses the same audio and video parameters for the outputs as the one
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specified for the inputs.
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@c man end
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@c man begin OPTIONS
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@section Main options
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@table @option
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@item -L
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Show license.
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@item -h
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Show help.
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@item -formats
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Show available formats, codecs, protocols, ...
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@item -f fmt
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Force format.
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@item -i filename
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input filename
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@item -y
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Overwrite output files.
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@item -t duration
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Set the recording time in seconds.
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@code{hh:mm:ss[.xxx]} syntax is also supported.
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@item -ss position
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Seek to given time position in seconds.
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@code{hh:mm:ss[.xxx]} syntax is also supported.
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@item -title string
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Set the title.
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@item -author string
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Set the author.
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@item -copyright string
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Set the copyright.
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@item -comment string
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Set the comment.
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@item -track number
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Set the track.
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@item -year number
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Set the year.
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@item -target type
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Specify target file type ("vcd", "svcd", "dvd", "dv", "pal-vcd",
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"ntsc-svcd", ... ). All the format options (bitrate, codecs,
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buffer sizes) are then set automatically. You can just type:
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@example
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ffmpeg -i myfile.avi -target vcd /tmp/vcd.mpg
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@end example
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Nevertheless you can specify additional options as long as you know
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they do not conflict with the standard, as in:
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@example
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ffmpeg -i myfile.avi -target vcd -bf 2 /tmp/vcd.mpg
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@end example
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@item -itsoffset offset
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Set the input time offset in seconds.
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@code{[-]hh:mm:ss[.xxx]} syntax is also supported.
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This option affects all the input files that follow it.
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The offset is added to the timestamps of the input files.
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Specifying a positive offset means that the corresponding
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streams are delayed by 'offset' seconds.
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@end table
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@section Video Options
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@table @option
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@item -b bitrate
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Set the video bitrate in bit/s (default = 200 kb/s).
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@item -r fps
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Set frame rate (default = 25).
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@item -s size
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Set frame size. The format is @samp{wxh} (default = 160x128).
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The following abbreviations are recognized:
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@table @samp
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@item sqcif
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128x96
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@item qcif
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176x144
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@item cif
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352x288
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@item 4cif
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704x576
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@end table
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@item -aspect aspect
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Set aspect ratio (4:3, 16:9 or 1.3333, 1.7777).
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@item -croptop size
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Set top crop band size (in pixels).
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@item -cropbottom size
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Set bottom crop band size (in pixels).
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@item -cropleft size
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Set left crop band size (in pixels).
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@item -cropright size
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Set right crop band size (in pixels).
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@item -padtop size
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Set top pad band size (in pixels).
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@item -padbottom size
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Set bottom pad band size (in pixels).
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@item -padleft size
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Set left pad band size (in pixels).
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@item -padright size
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Set right pad band size (in pixels).
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@item -padcolor (hex color)
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Set color of padded bands. The value for padcolor is expressed
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as a six digit hexadecimal number where the first two digits
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represent red, the middle two digits green and last two digits
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blue (default = 000000 (black)).
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@item -vn
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Disable video recording.
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@item -bt tolerance
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Set video bitrate tolerance (in bit/s).
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@item -maxrate bitrate
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Set max video bitrate tolerance (in bit/s).
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@item -minrate bitrate
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Set min video bitrate tolerance (in bit/s).
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@item -bufsize size
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Set rate control buffer size (in bits).
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@item -vcodec codec
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Force video codec to @var{codec}. Use the @code{copy} special value to
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tell that the raw codec data must be copied as is.
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@item -sameq
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Use same video quality as source (implies VBR).
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@item -pass n
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Select the pass number (1 or 2). It is useful to do two pass
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encoding. The statistics of the video are recorded in the first
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pass and the video is generated at the exact requested bitrate
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in the second pass.
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@item -passlogfile file
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Set two pass logfile name to @var{file}.
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@end table
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@section Advanced Video Options
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@table @option
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@item -g gop_size
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Set the group of pictures size.
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@item -intra
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Use only intra frames.
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@item -qscale q
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Use fixed video quantiser scale (VBR).
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@item -qmin q
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minimum video quantiser scale (VBR)
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@item -qmax q
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maximum video quantiser scale (VBR)
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@item -qdiff q
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maximum difference between the quantiser scales (VBR)
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@item -qblur blur
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video quantiser scale blur (VBR)
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@item -qcomp compression
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video quantiser scale compression (VBR)
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@item -rc_init_cplx complexity
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initial complexity for single pass encoding
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@item -b_qfactor factor
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qp factor between P- and B-frames
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@item -i_qfactor factor
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qp factor between P- and I-frames
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@item -b_qoffset offset
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qp offset between P- and B-frames
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@item -i_qoffset offset
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qp offset between P- and I-frames
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@item -rc_eq equation
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Set rate control equation (@pxref{FFmpeg formula
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evaluator}) (default = @code{tex^qComp}).
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@item -rc_override override
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rate control override for specific intervals
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@item -me method
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Set motion estimation method to @var{method}.
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Available methods are (from lowest to best quality):
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@table @samp
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@item zero
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Try just the (0, 0) vector.
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@item phods
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@item log
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@item x1
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@item epzs
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(default method)
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@item full
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exhaustive search (slow and marginally better than epzs)
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@end table
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@item -dct_algo algo
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Set DCT algorithm to @var{algo}. Available values are:
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@table @samp
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@item 0
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FF_DCT_AUTO (default)
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@item 1
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FF_DCT_FASTINT
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@item 2
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FF_DCT_INT
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@item 3
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FF_DCT_MMX
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@item 4
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FF_DCT_MLIB
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@item 5
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FF_DCT_ALTIVEC
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@end table
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@item -idct_algo algo
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Set IDCT algorithm to @var{algo}. Available values are:
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@table @samp
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@item 0
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FF_IDCT_AUTO (default)
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@item 1
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FF_IDCT_INT
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@item 2
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FF_IDCT_SIMPLE
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@item 3
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FF_IDCT_SIMPLEMMX
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@item 4
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FF_IDCT_LIBMPEG2MMX
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@item 5
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FF_IDCT_PS2
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@item 6
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FF_IDCT_MLIB
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@item 7
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FF_IDCT_ARM
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@item 8
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FF_IDCT_ALTIVEC
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@item 9
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FF_IDCT_SH4
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@item 10
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FF_IDCT_SIMPLEARM
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@end table
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@item -er n
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Set error resilience to @var{n}.
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@table @samp
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@item 1
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FF_ER_CAREFUL (default)
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@item 2
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FF_ER_COMPLIANT
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@item 3
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FF_ER_AGGRESSIVE
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@item 4
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FF_ER_VERY_AGGRESSIVE
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@end table
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@item -ec bit_mask
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Set error concealment to @var{bit_mask}. @var{bit_mask} is a bit mask of
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the following values:
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@table @samp
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@item 1
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FF_EC_GUESS_MVS (default = enabled)
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@item 2
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FF_EC_DEBLOCK (default = enabled)
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@end table
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@item -bf frames
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Use 'frames' B-frames (supported for MPEG-1, MPEG-2 and MPEG-4).
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@item -mbd mode
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macroblock decision
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@table @samp
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@item 0
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FF_MB_DECISION_SIMPLE: Use mb_cmp (cannot change it yet in FFmpeg).
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@item 1
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FF_MB_DECISION_BITS: Choose the one which needs the fewest bits.
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@item 2
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FF_MB_DECISION_RD: rate distortion
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@end table
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@item -4mv
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Use four motion vector by macroblock (MPEG-4 only).
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@item -part
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Use data partitioning (MPEG-4 only).
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@item -bug param
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Work around encoder bugs that are not auto-detected.
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@item -strict strictness
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How strictly to follow the standards.
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@item -aic
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Enable Advanced intra coding (h263+).
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@item -umv
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Enable Unlimited Motion Vector (h263+)
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@item -deinterlace
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Deinterlace pictures.
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@item -ilme
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Force interlacing support in encoder (MPEG-2 and MPEG-4 only).
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Use this option if your input file is interlaced and you want
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to keep the interlaced format for minimum losses.
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The alternative is to deinterlace the input stream with
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@option{-deinterlace}, but deinterlacing introduces losses.
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@item -psnr
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Calculate PSNR of compressed frames.
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@item -vstats
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Dump video coding statistics to @file{vstats_HHMMSS.log}.
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@item -vhook module
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Insert video processing @var{module}. @var{module} contains the module
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name and its parameters separated by spaces.
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@end table
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@section Audio Options
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@table @option
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@item -ar freq
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Set the audio sampling frequency (default = 44100 Hz).
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@item -ab bitrate
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Set the audio bitrate in kbit/s (default = 64).
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@item -ac channels
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Set the number of audio channels (default = 1).
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@item -an
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Disable audio recording.
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@item -acodec codec
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Force audio codec to @var{codec}. Use the @code{copy} special value to
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specify that the raw codec data must be copied as is.
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@end table
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@section Audio/Video grab options
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@table @option
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@item -vd device
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sEt video grab device (e.g. @file{/dev/video0}).
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@item -vc channel
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Set video grab channel (DV1394 only).
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@item -tvstd standard
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Set television standard (NTSC, PAL (SECAM)).
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@item -dv1394
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Set DV1394 grab.
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@item -ad device
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Set audio device (e.g. @file{/dev/dsp}).
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@end table
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@section Advanced options
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@table @option
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@item -map input stream id[:input stream id]
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Set stream mapping from input streams to output streams.
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Just enumerate the input streams in the order you want them in the output.
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[input stream id] sets the (input) stream to sync against.
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@item -debug
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Print specific debug info.
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@item -benchmark
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Add timings for benchmarking.
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@item -hex
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Dump each input packet.
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@item -bitexact
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Only use bit exact algorithms (for codec testing).
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@item -ps size
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Set packet size in bits.
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@item -re
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Read input at native frame rate. Mainly used to simulate a grab device.
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@item -loop
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Loop over the input stream. Currently it works only for image
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streams. This option is used for automatic FFserver testing.
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@item -loop_output number_of_times
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Repeatedly loop output for formats that support looping such as animated GIF
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(0 will loop the output infinitely).
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@item -vsync parameter
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Video sync method. Video will be stretched/squeezed to match the timestamps,
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it is done by duplicating and dropping frames. With -map you can select from
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which stream the timestamps should be taken. You can leave either video or
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audio unchanged and sync the remaining stream(s) to the unchanged one.
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@item -async samples_per_second
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Audio sync method. "Stretches/squeezes" the audio stream to match the timestamps,
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the parameter is the maximum samples per second by which the audio is changed.
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-async 1 is a special case where only the start of the audio stream is corrected
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without any later correction.
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@end table
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@node FFmpeg formula evaluator
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@section FFmpeg formula evaluator
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When evaluating a rate control string, FFmpeg uses an internal formula
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evaluator.
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The following binary operators are available: @code{+}, @code{-},
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@code{*}, @code{/}, @code{^}.
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The following unary operators are available: @code{+}, @code{-},
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@code{(...)}.
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The following functions are available:
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@table @var
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@item sinh(x)
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@item cosh(x)
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@item tanh(x)
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@item sin(x)
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@item cos(x)
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@item tan(x)
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@item exp(x)
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@item log(x)
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@item squish(x)
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@item gauss(x)
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@item abs(x)
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@item max(x, y)
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@item min(x, y)
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@item gt(x, y)
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@item lt(x, y)
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@item eq(x, y)
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@item bits2qp(bits)
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@item qp2bits(qp)
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@end table
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The following constants are available:
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@table @var
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@item PI
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@item E
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@item iTex
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@item pTex
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@item tex
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@item mv
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@item fCode
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@item iCount
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@item mcVar
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@item var
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@item isI
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@item isP
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@item isB
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@item avgQP
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@item qComp
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@item avgIITex
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@item avgPITex
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@item avgPPTex
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@item avgBPTex
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@item avgTex
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@end table
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@c man end
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@ignore
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@setfilename ffmpeg
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@settitle FFmpeg video converter
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@c man begin SEEALSO
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ffserver(1), ffplay(1) and the HTML documentation of @file{ffmpeg}.
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@c man end
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@c man begin AUTHOR
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Fabrice Bellard
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@c man end
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@end ignore
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@section Protocols
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The filename can be @file{-} to read from standard input or to write
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to standard output.
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FFmpeg also handles many protocols specified with an URL syntax.
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Use 'ffmpeg -formats' to see a list of the supported protocols.
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The protocol @code{http:} is currently used only to communicate with
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FFserver (see the FFserver documentation). When FFmpeg will be a
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video player it will also be used for streaming :-)
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@chapter Tips
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@itemize
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@item For streaming at very low bitrate application, use a low frame rate
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and a small GOP size. This is especially true for RealVideo where
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the Linux player does not seem to be very fast, so it can miss
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frames. An example is:
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@example
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ffmpeg -g 3 -r 3 -t 10 -b 50k -s qcif -f rv10 /tmp/b.rm
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@end example
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@item  The parameter 'q' which is displayed while encoding is the current
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quantizer. The value 1 indicates that a very good quality could
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be achieved. The value 31 indicates the worst quality. If q=31 appears
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too often, it means that the encoder cannot compress enough to meet
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your bitrate. You must either increase the bitrate, decrease the
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frame rate or decrease the frame size.
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@item If your computer is not fast enough, you can speed up the
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compression at the expense of the compression ratio. You can use
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'-me zero' to speed up motion estimation, and '-intra' to disable
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motion estimation completely (you have only I-frames, which means it
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is about as good as JPEG compression).
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@item To have very low audio bitrates, reduce the sampling frequency
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(down to 22050 kHz for MPEG audio, 22050 or 11025 for AC3).
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@item To have a constant quality (but a variable bitrate), use the option
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'-qscale n' when 'n' is between 1 (excellent quality) and 31 (worst
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quality).
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@item When converting video files, you can use the '-sameq' option which
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uses the same quality factor in the encoder as in the decoder.
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It allows almost lossless encoding.
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@end itemize
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@chapter Supported File Formats and Codecs
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You can use the @code{-formats} option to have an exhaustive list.
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@section File Formats
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FFmpeg supports the following file formats through the @code{libavformat}
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library:
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@multitable @columnfractions .4 .1 .1 .4
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@item Supported File Format @tab Encoding @tab Decoding @tab Comments
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@item MPEG audio @tab X @tab X
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@item MPEG-1 systems @tab X  @tab  X
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@tab muxed audio and video
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@item MPEG-2 PS @tab X  @tab  X
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@tab also known as @code{VOB} file
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@item MPEG-2 TS @tab    @tab  X
667
@tab also known as DVB Transport Stream
668
@item ASF@tab X @tab X
669
@item AVI@tab X @tab X
670
@item WAV@tab X @tab X
671
@item Macromedia Flash@tab X @tab X
672
@tab Only embedded audio is decoded.
673
@item FLV              @tab  X @tab X
674
@tab Macromedia Flash video files
675
@item Real Audio and Video @tab X @tab X
676
@item Raw AC3 @tab X  @tab  X
677
@item Raw MJPEG @tab X  @tab  X
678
@item Raw MPEG video @tab X  @tab  X
679
@item Raw PCM8/16 bits, mulaw/Alaw@tab X  @tab  X
680
@item Raw CRI ADX audio @tab X  @tab  X
681
@item Raw Shorten audio @tab    @tab  X
682
@item SUN AU format @tab X  @tab  X
683
@item NUT @tab X @tab X @tab NUT Open Container Format
684
@item QuickTime        @tab X @tab  X
685
@item MPEG-4           @tab X @tab  X
686
@tab MPEG-4 is a variant of QuickTime.
687
@item Raw MPEG4 video  @tab  X @tab  X
688
@item DV               @tab  X @tab  X
689
@item 4xm              @tab    @tab X
690
@tab 4X Technologies format, used in some games.
691
@item Playstation STR  @tab    @tab X
692
@item Id RoQ           @tab    @tab X
693
@tab Used in Quake III, Jedi Knight 2, other computer games.
694
@item Interplay MVE    @tab    @tab X
695
@tab Format used in various Interplay computer games.
696
@item WC3 Movie        @tab    @tab X
697
@tab Multimedia format used in Origin's Wing Commander III computer game.
698
@item Sega FILM/CPK    @tab    @tab X
699
@tab Used in many Sega Saturn console games.
700
@item Westwood Studios VQA/AUD  @tab    @tab X
701
@tab Multimedia formats used in Westwood Studios games.
702
@item Id Cinematic (.cin) @tab    @tab X
703
@tab Used in Quake II.
704
@item FLIC format      @tab    @tab X
705
@tab .fli/.flc files
706
@item Sierra VMD       @tab    @tab X
707
@tab Used in Sierra CD-ROM games.
708
@item Sierra Online    @tab    @tab X
709
@tab .sol files used in Sierra Online games.
710
@item Matroska         @tab    @tab X
711
@item Electronic Arts Multimedia    @tab    @tab X
712
@tab Used in various EA games; files have extensions like WVE and UV2.
713
@item Nullsoft Video (NSV) format @tab    @tab X
714
@item ADTS AAC audio @tab X @tab X
715
@item Creative VOC @tab X @tab X @tab Created for the Sound Blaster Pro.
716
@item American Laser Games MM  @tab    @tab X
717
@tab Multimedia format used in games like Mad Dog McCree
718
@item AVS @tab    @tab X
719
@tab Multimedia format used by the Creature Shock game.
720
@item Smacker @tab    @tab X
721
@tab Multimedia format used by many games.
722
@item GXF @tab    @tab X
723
@end multitable
724

    
725
@code{X} means that encoding (resp. decoding) is supported.
726

    
727
@section Image Formats
728

    
729
FFmpeg can read and write images for each frame of a video sequence. The
730
following image formats are supported:
731

    
732
@multitable @columnfractions .4 .1 .1 .4
733
@item Supported Image Format @tab Encoding @tab Decoding @tab Comments
734
@item PGM, PPM     @tab X @tab X
735
@item PAM          @tab X @tab X @tab PAM is a PNM extension with alpha support.
736
@item PGMYUV       @tab X @tab X @tab PGM with U and V components in YUV 4:2:0
737
@item JPEG         @tab X @tab X @tab Progressive JPEG is not supported.
738
@item .Y.U.V       @tab X @tab X @tab one raw file per component
739
@item animated GIF @tab X @tab X @tab Only uncompressed GIFs are generated.
740
@item PNG          @tab X @tab X @tab 2 bit and 4 bit/pixel not supported yet.
741
@item SGI          @tab X @tab X @tab SGI RGB image format
742
@end multitable
743

    
744
@code{X} means that encoding (resp. decoding) is supported.
745

    
746
@section Video Codecs
747

    
748
@multitable @columnfractions .4 .1 .1 .4
749
@item Supported Codec @tab Encoding @tab Decoding @tab Comments
750
@item MPEG-1 video           @tab  X  @tab  X
751
@item MPEG-2 video           @tab  X  @tab  X
752
@item MPEG-4                 @tab  X  @tab  X @tab also known as DivX4/5
753
@item MSMPEG4 V1             @tab  X  @tab  X
754
@item MSMPEG4 V2             @tab  X  @tab  X
755
@item MSMPEG4 V3             @tab  X  @tab  X @tab also known as DivX3
756
@item WMV7                   @tab  X  @tab  X
757
@item WMV8                   @tab  X  @tab  X @tab not completely working
758
@item H.261                  @tab  X  @tab  X
759
@item H.263(+)               @tab  X  @tab  X @tab also known as RealVideo 1.0
760
@item H.264                  @tab     @tab  X
761
@item RealVideo 1.0          @tab  X  @tab  X
762
@item RealVideo 2.0          @tab  X  @tab  X
763
@item MJPEG                  @tab  X  @tab  X
764
@item lossless MJPEG         @tab  X  @tab  X
765
@item JPEG-LS                @tab  X  @tab  X @tab fourcc: MJLS, lossless and near-lossless is supported
766
@item Apple MJPEG-B          @tab     @tab  X
767
@item Sunplus MJPEG          @tab     @tab  X @tab fourcc: SP5X
768
@item DV                     @tab  X  @tab  X
769
@item HuffYUV                @tab  X  @tab  X
770
@item FFmpeg Video 1         @tab  X  @tab  X @tab experimental lossless codec (fourcc: FFV1)
771
@item FFmpeg Snow            @tab  X  @tab  X @tab experimental wavelet codec (fourcc: SNOW)
772
@item Asus v1                @tab  X  @tab  X @tab fourcc: ASV1
773
@item Asus v2                @tab  X  @tab  X @tab fourcc: ASV2
774
@item Creative YUV           @tab     @tab  X @tab fourcc: CYUV
775
@item Sorenson Video 1       @tab  X  @tab  X @tab fourcc: SVQ1
776
@item Sorenson Video 3       @tab     @tab  X @tab fourcc: SVQ3
777
@item On2 VP3                @tab     @tab  X @tab still experimental
778
@item On2 VP5                @tab     @tab  X @tab fourcc: VP50
779
@item On2 VP6                @tab     @tab  X @tab fourcc: VP62
780
@item Theora                 @tab     @tab  X @tab still experimental
781
@item Intel Indeo 3          @tab     @tab  X
782
@item FLV                    @tab  X  @tab  X @tab Sorenson H.263 used in Flash
783
@item Flash Screen Video     @tab     @tab  X @tab fourcc: FSV1
784
@item ATI VCR1               @tab     @tab  X @tab fourcc: VCR1
785
@item ATI VCR2               @tab     @tab  X @tab fourcc: VCR2
786
@item Cirrus Logic AccuPak   @tab     @tab  X @tab fourcc: CLJR
787
@item 4X Video               @tab     @tab  X @tab Used in certain computer games.
788
@item Sony Playstation MDEC  @tab     @tab  X
789
@item Id RoQ                 @tab     @tab  X @tab Used in Quake III, Jedi Knight 2, other computer games.
790
@item Xan/WC3                @tab     @tab  X @tab Used in Wing Commander III .MVE files.
791
@item Interplay Video        @tab     @tab  X @tab Used in Interplay .MVE files.
792
@item Apple Animation        @tab     @tab  X @tab fourcc: 'rle '
793
@item Apple Graphics         @tab     @tab  X @tab fourcc: 'smc '
794
@item Apple Video            @tab     @tab  X @tab fourcc: rpza
795
@item Apple QuickDraw        @tab     @tab  X @tab fourcc: qdrw
796
@item Cinepak                @tab     @tab  X
797
@item Microsoft RLE          @tab     @tab  X
798
@item Microsoft Video-1      @tab     @tab  X
799
@item Westwood VQA           @tab     @tab  X
800
@item Id Cinematic Video     @tab     @tab  X @tab Used in Quake II.
801
@item Planar RGB             @tab     @tab  X @tab fourcc: 8BPS
802
@item FLIC video             @tab     @tab  X
803
@item Duck TrueMotion v1     @tab     @tab  X @tab fourcc: DUCK
804
@item Duck TrueMotion v2     @tab     @tab  X @tab fourcc: TM20
805
@item VMD Video              @tab     @tab  X @tab Used in Sierra VMD files.
806
@item MSZH                   @tab     @tab  X @tab Part of LCL
807
@item ZLIB                   @tab  X  @tab  X @tab Part of LCL, encoder experimental
808
@item TechSmith Camtasia     @tab     @tab  X @tab fourcc: TSCC
809
@item IBM Ultimotion         @tab     @tab  X @tab fourcc: ULTI
810
@item Miro VideoXL           @tab     @tab  X @tab fourcc: VIXL
811
@item QPEG                   @tab     @tab  X @tab fourccs: QPEG, Q1.0, Q1.1
812
@item LOCO                   @tab     @tab  X @tab
813
@item Winnov WNV1            @tab     @tab  X @tab
814
@item Autodesk Animator Studio Codec  @tab     @tab  X @tab fourcc: AASC
815
@item Fraps FPS1             @tab     @tab  X @tab
816
@item CamStudio              @tab     @tab  X @tab fourcc: CSCD
817
@item American Laser Games Video  @tab    @tab X @tab Used in games like Mad Dog McCree
818
@item ZMBV                   @tab     @tab  X @tab
819
@item AVS Video              @tab     @tab  X @tab Video encoding used by the Creature Shock game.
820
@item Smacker Video          @tab     @tab  X @tab Video encoding used in Smacker.
821
@item RTjpeg                 @tab     @tab  X @tab Video encoding used in NuppelVideo files.
822
@item KMVC                   @tab     @tab  X @tab Codec used in Worms games.
823
@item VMware Video           @tab     @tab  X @tab Codec used in videos captured by VMware.
824
@end multitable
825

    
826
@code{X} means that encoding (resp. decoding) is supported.
827

    
828
@section Audio Codecs
829

    
830
@multitable @columnfractions .4 .1 .1 .1 .7
831
@item Supported Codec @tab Encoding @tab Decoding @tab Comments
832
@item MPEG audio layer 2     @tab  IX  @tab  IX
833
@item MPEG audio layer 1/3   @tab IX   @tab  IX
834
@tab MP3 encoding is supported through the external library LAME.
835
@item AC3                    @tab  IX  @tab  IX
836
@tab liba52 is used internally for decoding.
837
@item Vorbis                 @tab  X   @tab  X
838
@tab Supported through the external library libvorbis.
839
@item WMA V1/V2              @tab      @tab X
840
@item AAC                    @tab X    @tab X
841
@tab Supported through the external library libfaac/libfaad.
842
@item Microsoft ADPCM        @tab X    @tab X
843
@item MS IMA ADPCM           @tab X    @tab X
844
@item QT IMA ADPCM           @tab      @tab X
845
@item 4X IMA ADPCM           @tab      @tab X
846
@item G.726  ADPCM           @tab X    @tab X
847
@item Duck DK3 IMA ADPCM     @tab      @tab X
848
@tab Used in some Sega Saturn console games.
849
@item Duck DK4 IMA ADPCM     @tab      @tab X
850
@tab Used in some Sega Saturn console games.
851
@item Westwood Studios IMA ADPCM @tab      @tab X
852
@tab Used in Westwood Studios games like Command and Conquer.
853
@item SMJPEG IMA ADPCM       @tab      @tab X
854
@tab Used in certain Loki game ports.
855
@item CD-ROM XA ADPCM        @tab      @tab X
856
@item CRI ADX ADPCM          @tab X    @tab X
857
@tab Used in Sega Dreamcast games.
858
@item Electronic Arts ADPCM  @tab      @tab X
859
@tab Used in various EA titles.
860
@item Creative ADPCM         @tab      @tab X
861
@tab 16 -> 4, 8 -> 4, 8 -> 3, 8 -> 2
862
@item RA144                  @tab      @tab X
863
@tab Real 14400 bit/s codec
864
@item RA288                  @tab      @tab X
865
@tab Real 28800 bit/s codec
866
@item RADnet                 @tab X    @tab IX
867
@tab Real low bitrate AC3 codec, liba52 is used for decoding.
868
@item AMR-NB                 @tab X    @tab X
869
@tab Supported through an external library.
870
@item AMR-WB                 @tab X    @tab X
871
@tab Supported through an external library.
872
@item DV audio               @tab      @tab X
873
@item Id RoQ DPCM            @tab      @tab X
874
@tab Used in Quake III, Jedi Knight 2, other computer games.
875
@item Interplay MVE DPCM     @tab      @tab X
876
@tab Used in various Interplay computer games.
877
@item Xan DPCM               @tab      @tab X
878
@tab Used in Origin's Wing Commander IV AVI files.
879
@item Sierra Online DPCM     @tab      @tab X
880
@tab Used in Sierra Online game audio files.
881
@item Apple MACE 3           @tab      @tab X
882
@item Apple MACE 6           @tab      @tab X
883
@item FLAC lossless audio    @tab      @tab X
884
@item Shorten lossless audio @tab      @tab X
885
@item Apple lossless audio   @tab      @tab X
886
@tab QuickTime fourcc 'alac'
887
@item FFmpeg Sonic           @tab X    @tab X
888
@tab experimental lossy/lossless codec
889
@item Qdesign QDM2           @tab      @tab X
890
@tab there are still some distortions
891
@item Real COOK              @tab      @tab X
892
@tab All versions except 5.1 are supported
893
@item DSP Group TrueSpeech   @tab      @tab X
894
@item True Audio (TTA)       @tab      @tab X
895
@item Smacker Audio          @tab      @tab X
896
@item WavPack Audio          @tab      @tab X
897
@end multitable
898

    
899
@code{X} means that encoding (resp. decoding) is supported.
900

    
901
@code{I} means that an integer-only version is available, too (ensures high
902
performance on systems without hardware floating point support).
903

    
904
@chapter Platform Specific information
905

    
906
@section Linux
907

    
908
FFmpeg should be compiled with at least GCC 2.95.3. GCC 3.2 is the
909
preferred compiler now for FFmpeg. All future optimizations will depend on
910
features only found in GCC 3.2.
911

    
912
@section BSD
913

    
914
BSD make will not build FFmpeg, you need to install and use GNU Make
915
(@file{gmake}).
916

    
917
@section Windows
918

    
919
@subsection Native Windows compilation
920

    
921
@itemize
922
@item Install the current versions of MSYS and MinGW from
923
@url{http://www.mingw.org/}. You can find detailed installation
924
instructions in the download section and the FAQ.
925

    
926
@item If you want to test the FFplay, also download
927
the MinGW development library of SDL 1.2.x
928
(@file{SDL-devel-1.2.x-mingw32.tar.gz}) from
929
@url{http://www.libsdl.org}. Unpack it in a temporary directory, and
930
unpack the archive @file{i386-mingw32msvc.tar.gz} in the MinGW tool
931
directory. Edit the @file{sdl-config} script so that it gives the
932
correct SDL directory when invoked.
933

    
934
@item Extract the current version of FFmpeg.
935

    
936
@item Start the MSYS shell (file @file{msys.bat}).
937

    
938
@item Change to the FFmpeg directory and follow
939
 the instructions of how to compile FFmpeg (file
940
@file{INSTALL}). Usually, launching @file{./configure} and @file{make}
941
suffices. If you have problems using SDL, verify that
942
@file{sdl-config} can be launched from the MSYS command line.
943

    
944
@item You can install FFmpeg in @file{Program Files/FFmpeg} by typing
945
@file{make install}. Don't forget to copy @file{SDL.dll} to the place
946
you launch @file{ffplay} from.
947

    
948
@end itemize
949

    
950
Notes:
951
@itemize
952

    
953
@item The target @file{make wininstaller} can be used to create a
954
Nullsoft based Windows installer for FFmpeg and FFplay. @file{SDL.dll}
955
must be copied to the FFmpeg directory in order to build the
956
installer.
957

    
958
@item By using @code{./configure --enable-shared} when configuring FFmpeg,
959
you can build @file{avcodec.dll} and @file{avformat.dll}. With
960
@code{make install} you install the FFmpeg DLLs and the associated
961
headers in @file{Program Files/FFmpeg}.
962

    
963
@item Visual C++ compatibility: If you used @code{./configure --enable-shared}
964
when configuring FFmpeg, FFmpeg tries to use the Microsoft Visual
965
C++ @code{lib} tool to build @code{avcodec.lib} and
966
@code{avformat.lib}. With these libraries you can link your Visual C++
967
code directly with the FFmpeg DLLs (see below).
968

    
969
@end itemize
970

    
971
@subsection Visual C++ compatibility
972

    
973
FFmpeg will not compile under Visual C++ -- and it has too many
974
dependencies on the GCC compiler to make a port viable. However,
975
if you want to use the FFmpeg libraries in your own applications,
976
you can still compile those applications using Visual C++. An
977
important restriction to this is that you have to use the
978
dynamically linked versions of the FFmpeg libraries (i.e. the
979
DLLs), and you have to make sure that Visual-C++-compatible
980
import libraries are created during the FFmpeg build process.
981

    
982
This description of how to use the FFmpeg libraries with Visual C++ is
983
based on Visual C++ 2005 Express Edition Beta 2. If you have a different
984
version, you might have to modify the procedures slightly.
985

    
986
Here are the step-by-step instructions for building the FFmpeg libraries
987
so they can be used with Visual C++:
988

    
989
@enumerate
990

    
991
@item Install Visual C++ (if you haven't done so already).
992

    
993
@item Install MinGW and MSYS as described above.
994

    
995
@item Add a call to @file{vcvars32.bat} (which sets up the environment
996
variables for the Visual C++ tools) as the first line of
997
@file{msys.bat}. The standard location for @file{vcvars32.bat} is
998
@file{C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat},
999
and the standard location for @file{msys.bat} is
1000
@file{C:\msys\1.0\msys.bat}. If this corresponds to your setup, add the
1001
following line as the first line of @file{msys.bat}:
1002

    
1003
@code{call "C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat"}
1004

    
1005
@item Start the MSYS shell (file @file{msys.bat}) and type @code{link.exe}.
1006
If you get a help message with the command line options of @code{link.exe},
1007
this means your environment variables are set up correctly, the
1008
Microsoft linker is on the path and will be used by FFmpeg to
1009
create Visual-C++-compatible import libraries.
1010

    
1011
@item Extract the current version of FFmpeg and change to the FFmpeg directory.
1012

    
1013
@item Type the command
1014
@code{./configure --enable-shared --disable-static --enable-memalign-hack}
1015
to configure and, if that didn't produce any errors,
1016
type @code{make} to build FFmpeg.
1017

    
1018
@item The subdirectories @file{libavformat}, @file{libavcodec}, and
1019
@file{libavutil} should now contain the files @file{avformat.dll},
1020
@file{avformat.lib}, @file{avcodec.dll}, @file{avcodec.lib},
1021
@file{avutil.dll}, and @file{avutil.lib}, respectively. Copy the three
1022
DLLs to your System32 directory (typically @file{C:\Windows\System32}).
1023

    
1024
@end enumerate
1025

    
1026
And here is how to use these libraries with Visual C++:
1027

    
1028
@enumerate
1029

    
1030
@item Create a new console application ("File / New / Project") and then
1031
select "Win32 Console Application". On the appropriate page of the
1032
Application Wizard, uncheck the "Precompiled headers" option.
1033

    
1034
@item Write the source code for your application, or, for testing, just
1035
copy the code from an existing sample application into the source file
1036
that Visual C++ has already created for you. (Note that your source
1037
filehas to have a @code{.cpp} extension; otherwise, Visual C++ won't
1038
compile the FFmpeg headers correctly because in C mode, it doesn't
1039
recognize the @code{inline} keyword.)  For example, you can copy
1040
@file{output_example.c} from the FFmpeg distribution (but you will
1041
have to make minor modifications so the code will compile under
1042
C++, see below).
1043

    
1044
@item Open the "Project / Properties" dialog box. In the "Configuration"
1045
combo box, select "All Configurations" so that the changes you make will
1046
affect both debug and release builds. In the tree view on the left hand
1047
side, select "C/C++ / General", then edit the "Additional Include
1048
Directories" setting to contain the complete paths to the
1049
@file{libavformat}, @file{libavcodec}, and @file{libavutil}
1050
subdirectories of your FFmpeg directory. Note that the directories have
1051
to be separated using semicolons. Now select "Linker / General" from the
1052
tree view and edit the "Additional Library Directories" setting to
1053
contain the same three directories.
1054

    
1055
@item Still in the "Project / Properties" dialog box, select "Linker / Input"
1056
from the tree view, then add the files @file{avformat.lib},
1057
@file{avcodec.lib}, and @file{avutil.lib} to the end of the "Additional
1058
Dependencies". Note that the names of the libraries have to be separated
1059
using spaces.
1060

    
1061
@item Now, select "C/C++ / Code Generation" from the tree view. Select
1062
"Debug" in the "Configuration" combo box. Make sure that "Runtime
1063
Library" is set to "Multi-threaded Debug DLL". Then, select "Release" in
1064
the "Configuration" combo box and make sure that "Runtime Library" is
1065
set to "Multi-threaded DLL".
1066

    
1067
@item Click "OK" to close the "Project / Properties" dialog box and build
1068
the application. Hopefully, it should compile and run cleanly. If you
1069
used @file{output_example.c} as your sample application, you will get a
1070
few compiler errors, but they are easy to fix. The first type of error
1071
occurs because Visual C++ doesn't allow an @code{int} to be converted to
1072
an @code{enum} without a cast. To solve the problem, insert the required
1073
casts (this error occurs once for a @code{CodecID} and once for a
1074
@code{CodecType}).  The second type of error occurs because C++ requires
1075
the return value of @code{malloc} to be cast to the exact type of the
1076
pointer it is being assigned to. Visual C++ will complain that, for
1077
example, @code{(void *)} is being assigned to @code{(uint8_t *)} without
1078
an explicit cast. So insert an explicit cast in these places to silence
1079
the compiler. The third type of error occurs because the @code{snprintf}
1080
library function is called @code{_snprintf} under Visual C++.  So just
1081
add an underscore to fix the problem. With these changes,
1082
@file{output_example.c} should compile under Visual C++, and the
1083
resulting executable should produce valid video files.
1084

    
1085
@end enumerate
1086

    
1087
@subsection Cross compilation for Windows with Linux
1088

    
1089
You must use the MinGW cross compilation tools available at
1090
@url{http://www.mingw.org/}.
1091

    
1092
Then configure FFmpeg with the following options:
1093
@example
1094
./configure --enable-mingw32 --cross-prefix=i386-mingw32msvc-
1095
@end example
1096
(you can change the cross-prefix according to the prefix chosen for the
1097
MinGW tools).
1098

    
1099
Then you can easily test FFmpeg with Wine
1100
(@url{http://www.winehq.com/}).
1101

    
1102
@subsection Compilation under Cygwin
1103

    
1104
Cygwin works very much like Unix.
1105

    
1106
Just install your Cygwin with all the "Base" packages, plus the
1107
following "Devel" ones:
1108
@example
1109
binutils, gcc-core, make, subversion
1110
@end example
1111

    
1112
Do not install binutils-20060709-1 (they are buggy on shared builds);
1113
use binutils-20050610-1 instead.
1114

    
1115
Then run
1116

    
1117
@example
1118
./configure --enable-static --disable-shared
1119
@end example
1120

    
1121
to make a static build or
1122

    
1123
@example
1124
./configure --enable-shared --disable-static
1125
@end example
1126

    
1127
to build shared libraries.
1128

    
1129
If you want to build FFmpeg with additional libraries, download Cygwin
1130
"Devel" packages for Ogg and Vorbis from any Cygwin packages repository
1131
and/or SDL, xvid, faac, faad2 packages from Cygwin Ports,
1132
(@url{http://cygwinports.dotsrc.org/}).
1133

    
1134
@subsection Crosscompilation for Windows under Cygwin
1135

    
1136
With Cygwin you can create Windows binaries that don't need the cygwin1.dll.
1137

    
1138
Just install your Cygwin as explained before, plus these additional
1139
"Devel" packages:
1140
@example
1141
gcc-mingw-core, mingw-runtime, mingw-zlib
1142
@end example
1143

    
1144
and add some special flags to your configure invocation.
1145

    
1146
For a static build run
1147
@example
1148
./configure --enable-mingw32 --enable-memalign-hack --enable-static --disable-shared --extra-cflags=-mno-cygwin --extra-libs=-mno-cygwin
1149
@end example
1150

    
1151
and for a build with shared libraries
1152
@example
1153
./configure --enable-mingw32 --enable-memalign-hack --enable-shared --disable-static --extra-cflags=-mno-cygwin --extra-libs=-mno-cygwin
1154
@end example
1155

    
1156
@section Mac OS X
1157

    
1158
@section BeOS
1159

    
1160
The configure script should guess the configuration itself.
1161
Networking support is currently not finished.
1162
errno issues fixed by Andrew Bachmann.
1163

    
1164
Old stuff:
1165

    
1166
Fran├žois Revol - revol at free dot fr - April 2002
1167

    
1168
The configure script should guess the configuration itself,
1169
however I still didn't test building on the net_server version of BeOS.
1170

    
1171
FFserver is broken (needs poll() implementation).
1172

    
1173
There are still issues with errno codes, which are negative in BeOS, and
1174
that FFmpeg negates when returning. This ends up turning errors into
1175
valid results, then crashes.
1176
(To be fixed)
1177

    
1178
@chapter Developers Guide
1179

    
1180
@section API
1181
@itemize @bullet
1182
@item libavcodec is the library containing the codecs (both encoding and
1183
decoding). Look at @file{libavcodec/apiexample.c} to see how to use it.
1184

    
1185
@item libavformat is the library containing the file format handling (mux and
1186
demux code for several formats). Look at @file{ffplay.c} to use it in a
1187
player. See @file{output_example.c} to use it to generate audio or video
1188
streams.
1189

    
1190
@end itemize
1191

    
1192
@section Integrating libavcodec or libavformat in your program
1193

    
1194
You can integrate all the source code of the libraries to link them
1195
statically to avoid any version problem. All you need is to provide a
1196
'config.mak' and a 'config.h' in the parent directory. See the defines
1197
generated by ./configure to understand what is needed.
1198

    
1199
You can use libavcodec or libavformat in your commercial program, but
1200
@emph{any patch you make must be published}. The best way to proceed is
1201
to send your patches to the FFmpeg mailing list.
1202

    
1203
@node Coding Rules
1204
@section Coding Rules
1205

    
1206
FFmpeg is programmed in the ISO C90 language with a few additional
1207
features from ISO C99, namely:
1208
@itemize @bullet
1209
@item
1210
the @samp{inline} keyword;
1211
@item
1212
@samp{//} comments;
1213
@item
1214
designated struct initializers (@samp{struct s x = @{ .i = 17 @};})
1215
@item
1216
compound literals (@samp{x = (struct s) @{ 17, 23 @};})
1217
@end itemize
1218

    
1219
These features are supported by all compilers we care about, so we won't
1220
accept patches to remove their use unless they absolutely don't impair
1221
clarity and performance.
1222

    
1223
All code must compile with GCC 2.95 and GCC 3.3. Currently, FFmpeg also
1224
compiles with several other compilers, such as the Compaq ccc compiler
1225
or Sun Studio 9, and we would like to keep it that way unless it would
1226
be exceedingly involved. To ensure compatibility, please don't use any
1227
additional C99 features or GCC extensions. Especially watch out for:
1228
@itemize @bullet
1229
@item
1230
mixing statements and declarations;
1231
@item
1232
@samp{long long} (use @samp{int64_t} instead);
1233
@item
1234
@samp{__attribute__} not protected by @samp{#ifdef __GNUC__} or similar;
1235
@item
1236
GCC statement expressions (@samp{(x = (@{ int y = 4; y; @})}).
1237
@end itemize
1238

    
1239
Indent size is 4.
1240
The presentation is the one specified by 'indent -i4 -kr -nut'.
1241
The TAB character is forbidden outside of Makefiles as is any
1242
form of trailing whitespace. Commits containing either will be
1243
rejected by the Subversion repository.
1244

    
1245
Main priority in FFmpeg is simplicity and small code size (=less
1246
bugs).
1247

    
1248
Comments: Use the JavaDoc/Doxygen
1249
format (see examples below) so that code documentation
1250
can be generated automatically. All nontrivial functions should have a comment
1251
above them explaining what the function does, even if it's just one sentence.
1252
All structures and their member variables should be documented, too.
1253
@example
1254
/**
1255
 * @@file mpeg.c
1256
 * MPEG codec.
1257
 * @@author ...
1258
 */
1259

    
1260
/**
1261
 * Summary sentence.
1262
 * more text ...
1263
 * ...
1264
 */
1265
typedef struct Foobar@{
1266
    int var1; /**< var1 description */
1267
    int var2; ///< var2 description
1268
    /** var3 description */
1269
    int var3;
1270
@} Foobar;
1271

    
1272
/**
1273
 * Summary sentence.
1274
 * more text ...
1275
 * ...
1276
 * @@param my_parameter description of my_parameter
1277
 * @@return return value description
1278
 */
1279
int myfunc(int my_parameter)
1280
...
1281
@end example
1282

    
1283
fprintf and printf are forbidden in libavformat and libavcodec,
1284
please use av_log() instead.
1285

    
1286
@section Development Policy
1287

    
1288
@enumerate
1289
@item
1290
   You must not commit code which breaks FFmpeg! (Meaning unfinished but
1291
   enabled code which breaks compilation or compiles but does not work or
1292
   breaks the regression tests)
1293
   You can commit unfinished stuff (for testing etc), but it must be disabled
1294
   (#ifdef etc) by default so it does not interfere with other developers'
1295
   work.
1296
@item
1297
   You don't have to over-test things. If it works for you, and you think it
1298
   should work for others, then commit. If your code has problems
1299
   (portability, triggers compiler bugs, unusual environment etc) they will be
1300
   reported and eventually fixed.
1301
@item
1302
   Do not commit unrelated changes together, split them into self-contained
1303
   pieces.
1304
@item
1305
   Do not change behavior of the program (renaming options etc) without
1306
   first discussing it on the ffmpeg-devel mailing list. Do not remove
1307
   functionality from the code. Just improve!
1308

    
1309
   Note: Redundant code can be removed.
1310
@item
1311
   Do not commit changes to the build system (Makefiles, configure script)
1312
   which change behavior, defaults etc, without asking first. The same
1313
   applies to compiler warning fixes, trivial looking fixes and to code
1314
   maintained by other developers. We usually have a reason for doing things
1315
   the way we do. Send your changes as patches to the ffmpeg-devel mailing
1316
   list, and if the code maintainers say OK, you may commit. This does not
1317
   apply to files you wrote and/or maintain.
1318
@item
1319
   We refuse source indentation and other cosmetic changes if they are mixed
1320
   with functional changes, such commits will be rejected and removed. Every
1321
   developer has his own indentation style, you should not change it. Of course
1322
   if you (re)write something, you can use your own style, even though we would
1323
   prefer if the indentation throughout FFmpeg was consistent (Many projects
1324
   force a given indentation style - we don't.). If you really need to make
1325
   indentation changes (try to avoid this), separate them strictly from real
1326
   changes.
1327

    
1328
   NOTE: If you had to put if()@{ .. @} over a large (> 5 lines) chunk of code,
1329
   then either do NOT change the indentation of the inner part within (don't
1330
   move it to the right)! or do so in a separate commit
1331
@item
1332
   Always fill out the commit log message. Describe in a few lines what you
1333
   changed and why. You can refer to mailing list postings if you fix a
1334
   particular bug. Comments such as "fixed!" or "Changed it." are unacceptable.
1335
@item
1336
   If you apply a patch by someone else, include the name and email address in
1337
   the log message. Since the ffmpeg-cvslog mailing list is publicly
1338
   archived you should add some SPAM protection to the email address. Send an
1339
   answer to ffmpeg-devel (or wherever you got the patch from) saying that
1340
   you applied the patch.
1341
@item
1342
    Do NOT commit to code actively maintained by others without permission.
1343
    Send a patch to ffmpeg-devel instead. If noone answers within a reasonable
1344
    timeframe (12h for build failures and security fixes, 3 days small changes,
1345
    1 week for big patches) then commit your patch if you think it's OK.
1346
    Also note, the maintainer can simply ask for more time to review!
1347
@item
1348
    Subscribe to the ffmpeg-cvslog mailing list. The diffs of all commits
1349
    are sent there and reviewed by all the other developers. Bugs and possible
1350
    improvements or general questions regarding commits are discussed there. We
1351
    expect you to react if problems with your code are uncovered.
1352
@item
1353
    Update the documentation if you change behavior or add features. If you are
1354
    unsure how best to do this, send a patch to ffmpeg-devel, the documentation
1355
    maintainer(s) will review and commit your stuff.
1356
@item
1357
    Never write to unallocated memory, never write over the end of arrays,
1358
    always check values read from some untrusted source before using them
1359
    as array index or other risky things.
1360
@item
1361
    Remember to check if you need to bump versions for the specific libav
1362
    parts (libavutil, libavcodec, libavformat) you are changing. You need
1363
    to change the version integer and the version string.
1364
    Incrementing the first component means no backward compatibility to
1365
    previous versions (e.g. removal of a function from the public API).
1366
    Incrementing the second component means backward compatible change
1367
    (e.g. addition of a function to the public API).
1368
    Incrementing the third component means a noteworthy binary compatible
1369
    change (e.g. encoder bug fix that matters for the decoder).
1370
@item
1371
    If you add a new codec, remember to update the changelog, add it to
1372
    the supported codecs table in the documentation and bump the second
1373
    component of the @file{libavcodec} version number appropriately. If
1374
    it has a fourcc, add it to @file{libavformat/avienc.c}, even if it
1375
    is only a decoder.
1376
@end enumerate
1377

    
1378
We think our rules are not too hard. If you have comments, contact us.
1379

    
1380
Note, these rules are mostly borrowed from the MPlayer project.
1381

    
1382
@section Submitting patches
1383

    
1384
First, (@pxref{Coding Rules}) above if you didn't yet.
1385

    
1386
When you submit your patch, try to send a unified diff (diff '-up'
1387
option). I cannot read other diffs :-)
1388

    
1389
Also please do not submit patches which contain several unrelated changes.
1390
Split them into individual self-contained patches; this makes reviewing
1391
them much easier.
1392

    
1393
Run the regression tests before submitting a patch so that you can
1394
verify that there are no big problems.
1395

    
1396
Patches should be posted as base64 encoded attachments (or any other
1397
encoding which ensures that the patch won't be trashed during
1398
transmission) to the ffmpeg-devel mailing list, see
1399
@url{http://lists.mplayerhq.hu/mailman/listinfo/ffmpeg-devel}
1400

    
1401
It also helps quite a bit if you tell us what the patch does (for example
1402
'replaces lrint by lrintf'), and why (for example '*BSD isn't C99 compliant
1403
and has no lrint()')
1404

    
1405
We reply to all submitted patches and either apply or reject with some
1406
explanation why, but sometimes we are quite busy so it can take a week or two.
1407

    
1408
@section Regression tests
1409

    
1410
Before submitting a patch (or committing to the repository), you should at least
1411
test that you did not break anything.
1412

    
1413
The regression tests build a synthetic video stream and a synthetic
1414
audio stream. These are then encoded and decoded with all codecs or
1415
formats. The CRC (or MD5) of each generated file is recorded in a
1416
result file. A 'diff' is launched to compare the reference results and
1417
the result file.
1418

    
1419
The regression tests then go on to test the FFserver code with a
1420
limited set of streams. It is important that this step runs correctly
1421
as well.
1422

    
1423
Run 'make test' to test all the codecs and formats.
1424

    
1425
Run 'make fulltest' to test all the codecs, formats and FFserver.
1426

    
1427
[Of course, some patches may change the results of the regression tests. In
1428
this case, the reference results of the regression tests shall be modified
1429
accordingly].
1430

    
1431
@bye