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\input texinfo @c -*- texinfo -*-
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@settitle ffmpeg Documentation
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@titlepage
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@center @titlefont{ffmpeg Documentation}
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@end titlepage
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@top
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@contents
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@chapter Synopsis
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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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@chapter Description
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@c man begin DESCRIPTION
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ffmpeg is a very fast video and audio converter that can also grab from
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a live audio/video source. It can also convert between arbitrary sample
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rates and resize video on the fly with a high quality polyphase filter.
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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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As a general rule, options are applied to the next specified
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file. Therefore, order is important, and you can have the same
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option on the command line multiple times. Each occurrence is
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then applied to the next input or output file.
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@itemize
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@item
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To set the video bitrate of the output file to 64kbit/s:
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@example
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ffmpeg -i input.avi -b 64k output.avi
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@end example
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@item
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To force the frame rate of the output file to 24 fps:
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@example
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ffmpeg -i input.avi -r 24 output.avi
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@end example
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@item
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To force the frame rate of the input file (valid for raw formats only)
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to 1 fps and the frame rate of the output file to 24 fps:
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@example
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ffmpeg -r 1 -i input.m2v -r 24 output.avi
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@end example
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@end itemize
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The format option may be needed for raw input 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 DESCRIPTION
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@chapter Options
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@c man begin OPTIONS
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@include fftools-common-opts.texi
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@section Main options
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@table @option
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@item -f @var{fmt}
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Force format.
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@item -i @var{filename}
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input file name
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@item -y
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Overwrite output files.
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@item -t @var{duration}
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Restrict the transcoded/captured video sequence
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to the duration specified in seconds.
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@code{hh:mm:ss[.xxx]} syntax is also supported.
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@item -fs @var{limit_size}
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Set the file size limit.
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@item -ss @var{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 -itsoffset @var{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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@item -timestamp @var{time}
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Set the recording timestamp in the container.
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The syntax for @var{time} is:
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@example
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now|([(YYYY-MM-DD|YYYYMMDD)[T|t| ]]((HH[:MM[:SS[.m...]]])|(HH[MM[SS[.m...]]]))[Z|z])
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@end example
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If the value is "now" it takes the current time.
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Time is local time unless 'Z' or 'z' is appended, in which case it is
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interpreted as UTC.
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If the year-month-day part is not specified it takes the current
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year-month-day.
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@item -metadata @var{key}=@var{value}
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Set a metadata key/value pair.
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For example, for setting the title in the output file:
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@example
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ffmpeg -i in.avi -metadata title="my title" out.flv
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@end example
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@item -v @var{number}
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Set the logging verbosity level.
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@item -target @var{type}
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Specify target file type ("vcd", "svcd", "dvd", "dv", "dv50", "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 -dframes @var{number}
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Set the number of data frames to record.
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@item -scodec @var{codec}
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Force subtitle codec ('copy' to copy stream).
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@item -newsubtitle
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Add a new subtitle stream to the current output stream.
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@item -slang @var{code}
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Set the ISO 639 language code (3 letters) of the current subtitle stream.
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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 @var{bitrate}
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Set the video bitrate in bit/s (default = 200 kb/s).
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@item -vframes @var{number}
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Set the number of video frames to record.
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@item -r @var{fps}
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Set frame rate (Hz value, fraction or abbreviation), (default = 25).
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@item -s @var{size}
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Set frame size. The format is @samp{wxh} (ffserver default = 160x128, ffmpeg default = same as source).
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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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@item 16cif
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1408x1152
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@item qqvga
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160x120
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@item qvga
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320x240
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@item vga
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640x480
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@item svga
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800x600
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@item xga
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1024x768
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@item uxga
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1600x1200
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@item qxga
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2048x1536
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@item sxga
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1280x1024
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@item qsxga
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2560x2048
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@item hsxga
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5120x4096
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@item wvga
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852x480
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@item wxga
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1366x768
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@item wsxga
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1600x1024
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@item wuxga
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1920x1200
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@item woxga
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2560x1600
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@item wqsxga
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3200x2048
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@item wquxga
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3840x2400
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@item whsxga
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6400x4096
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@item whuxga
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7680x4800
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@item cga
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320x200
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@item ega
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640x350
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@item hd480
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852x480
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@item hd720
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1280x720
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@item hd1080
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1920x1080
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@end table
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@item -aspect @var{aspect}
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Set aspect ratio (4:3, 16:9 or 1.3333, 1.7777).
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@item -croptop @var{size}
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@item -cropbottom @var{size}
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@item -cropleft @var{size}
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@item -cropright @var{size}
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All the crop options have been removed. Use -vf
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crop=width:height:x:y instead.
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@item -padtop @var{size}
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@item -padbottom @var{size}
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@item -padleft @var{size}
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@item -padright @var{size}
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@item -padcolor @var{hex_color}
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All the pad options have been removed. Use -vf
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pad=width:height:x:y:color instead.
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@item -vn
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Disable video recording.
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@item -bt @var{tolerance}
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Set video bitrate tolerance (in bits, default 4000k).
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Has a minimum value of: (target_bitrate/target_framerate).
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In 1-pass mode, bitrate tolerance specifies how far ratecontrol is
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willing to deviate from the target average bitrate value. This is
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not related to min/max bitrate. Lowering tolerance too much has
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an adverse effect on quality.
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@item -maxrate @var{bitrate}
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Set max video bitrate (in bit/s).
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Requires -bufsize to be set.
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@item -minrate @var{bitrate}
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Set min video bitrate (in bit/s).
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Most useful in setting up a CBR encode:
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@example
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ffmpeg -i myfile.avi -b 4000k -minrate 4000k -maxrate 4000k -bufsize 1835k out.m2v
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@end example
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It is of little use elsewise.
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@item -bufsize @var{size}
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Set video buffer verifier buffer size (in bits).
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@item -vcodec @var{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 quantizer as source (implies VBR).
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@item -pass @var{n}
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Select the pass number (1 or 2). It is used to do two-pass
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video encoding. The statistics of the video are recorded in the first
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pass into a log file (see also the option -passlogfile),
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and in the second pass that log file is used to generate the video
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at the exact requested bitrate.
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On pass 1, you may just deactivate audio and set output to null,
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examples for Windows and Unix:
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@example
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ffmpeg -i foo.mov -vcodec libxvid -pass 1 -an -f rawvideo -y NUL
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ffmpeg -i foo.mov -vcodec libxvid -pass 1 -an -f rawvideo -y /dev/null
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@end example
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@item -passlogfile @var{prefix}
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Set two-pass log file name prefix to @var{prefix}, the default file name
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prefix is ``ffmpeg2pass''. The complete file name will be
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@file{PREFIX-N.log}, where N is a number specific to the output
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stream.
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@item -newvideo
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Add a new video stream to the current output stream.
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@item -vlang @var{code}
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Set the ISO 639 language code (3 letters) of the current video stream.
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@item -vf @var{filter_graph}
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@var{filter_graph} is a description of the filter graph to apply to
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the input video.
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Use the option "-filters" to show all the available filters (including
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also sources and sinks).
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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 -pix_fmt @var{format}
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Set pixel format. Use 'list' as parameter to show all the supported
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pixel formats.
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@item -sws_flags @var{flags}
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Set SwScaler flags.
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@item -g @var{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 -vdt @var{n}
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Discard threshold.
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@item -qscale @var{q}
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Use fixed video quantizer scale (VBR).
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@item -qmin @var{q}
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minimum video quantizer scale (VBR)
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@item -qmax @var{q}
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maximum video quantizer scale (VBR)
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@item -qdiff @var{q}
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maximum difference between the quantizer scales (VBR)
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@item -qblur @var{blur}
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video quantizer scale blur (VBR) (range 0.0 - 1.0)
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@item -qcomp @var{compression}
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video quantizer scale compression (VBR) (default 0.5).
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Constant of ratecontrol equation. Recommended range for default rc_eq: 0.0-1.0
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@item -lmin @var{lambda}
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minimum video lagrange factor (VBR)
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@item -lmax @var{lambda}
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max video lagrange factor (VBR)
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@item -mblmin @var{lambda}
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minimum macroblock quantizer scale (VBR)
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@item -mblmax @var{lambda}
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maximum macroblock quantizer scale (VBR)
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These four options (lmin, lmax, mblmin, mblmax) use 'lambda' units,
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but you may use the QP2LAMBDA constant to easily convert from 'q' units:
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@example
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ffmpeg -i src.ext -lmax 21*QP2LAMBDA dst.ext
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@end example
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@item -rc_init_cplx @var{complexity}
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initial complexity for single pass encoding
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@item -b_qfactor @var{factor}
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qp factor between P- and B-frames
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@item -i_qfactor @var{factor}
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qp factor between P- and I-frames
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@item -b_qoffset @var{offset}
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qp offset between P- and B-frames
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@item -i_qoffset @var{offset}
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qp offset between P- and I-frames
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@item -rc_eq @var{equation}
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Set rate control equation (see section "Expression Evaluation")
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(default = @code{tex^qComp}).
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When computing the rate control equation expression, besides the
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standard functions defined in the section "Expression Evaluation", the
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following functions are available:
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@table @var
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@item bits2qp(bits)
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@item qp2bits(qp)
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@end table
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and the following constants are available:
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@table @var
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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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@item -rc_override @var{override}
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rate control override for specific intervals
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@item -me_method @var{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 hex
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@item umh
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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 @var{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 @var{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 @var{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 @var{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 @var{frames}
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Use 'frames' B-frames (supported for MPEG-1, MPEG-2 and MPEG-4).
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@item -mbd @var{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 @var{param}
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Work around encoder bugs that are not auto-detected.
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@item -strict @var{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 -vstats_file @var{file}
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Dump video coding statistics to @var{file}.
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@item -top @var{n}
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top=1/bottom=0/auto=-1 field first
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@item -dc @var{precision}
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Intra_dc_precision.
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@item -vtag @var{fourcc/tag}
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Force video tag/fourcc.
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@item -qphist
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Show QP histogram.
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@item -vbsf @var{bitstream_filter}
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Bitstream filters available are "dump_extra", "remove_extra", "noise", "h264_mp4toannexb", "imxdump", "mjpegadump", "mjpeg2jpeg".
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@example
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ffmpeg -i h264.mp4 -vcodec copy -vbsf h264_mp4toannexb -an out.h264
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@end example
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@item -force_key_frames @var{time}[,@var{time}...]
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Force key frames at the specified timestamps, more precisely at the first
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frames after each specified time.
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This option can be useful to ensure that a seek point is present at a
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chapter mark or any other designated place in the output file.
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The timestamps must be specified in ascending order.
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@end table
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@section Audio Options
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@table @option
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@item -aframes @var{number}
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Set the number of audio frames to record.
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@item -ar @var{freq}
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Set the audio sampling frequency. For input streams it is set by
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default to 44100 Hz, for output streams it is set by default to the
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frequency of the input stream. If the input file has audio streams
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with different frequencies, the behaviour is undefined.
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@item -ab @var{bitrate}
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Set the audio bitrate in bit/s (default = 64k).
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@item -aq @var{q}
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Set the audio quality (codec-specific, VBR).
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@item -ac @var{channels}
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Set the number of audio channels. For input streams it is set by
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default to 1, for output streams it is set by default to the same
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number of audio channels in input. If the input file has audio streams
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with different channel count, the behaviour is undefined.
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@item -an
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Disable audio recording.
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@item -acodec @var{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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@item -newaudio
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Add a new audio track to the output file. If you want to specify parameters,
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do so before @code{-newaudio} (@code{-acodec}, @code{-ab}, etc..).
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Mapping will be done automatically, if the number of output streams is equal to
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the number of input streams, else it will pick the first one that matches. You
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can override the mapping using @code{-map} as usual.
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Example:
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@example
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ffmpeg -i file.mpg -vcodec copy -acodec ac3 -ab 384k test.mpg -acodec mp2 -ab 192k -newaudio
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@end example
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@item -alang @var{code}
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Set the ISO 639 language code (3 letters) of the current audio stream.
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@end table
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@section Advanced Audio options:
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@table @option
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@item -atag @var{fourcc/tag}
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Force audio tag/fourcc.
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@item -audio_service_type @var{type}
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Set the type of service that the audio stream contains.
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@table @option
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@item ma
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Main Audio Service (default)
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@item ef
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Effects
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@item vi
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Visually Impaired
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@item hi
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Hearing Impaired
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@item di
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Dialogue
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@item co
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Commentary
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@item em
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Emergency
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@item vo
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Voice Over
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@item ka
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Karaoke
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@end table
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@item -absf @var{bitstream_filter}
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Bitstream filters available are "dump_extra", "remove_extra", "noise", "mp3comp", "mp3decomp".
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@end table
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@section Subtitle options:
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@table @option
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@item -scodec @var{codec}
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Force subtitle codec ('copy' to copy stream).
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@item -newsubtitle
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Add a new subtitle stream to the current output stream.
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@item -slang @var{code}
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Set the ISO 639 language code (3 letters) of the current subtitle stream.
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@item -sn
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Disable subtitle recording.
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@item -sbsf @var{bitstream_filter}
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Bitstream filters available are "mov2textsub", "text2movsub".
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@example
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ffmpeg -i file.mov -an -vn -sbsf mov2textsub -scodec copy -f rawvideo sub.txt
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@end example
629
@end table
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@section Audio/Video grab options
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@table @option
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@item -vc @var{channel}
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Set video grab channel (DV1394 only).
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@item -tvstd @var{standard}
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Set television standard (NTSC, PAL (SECAM)).
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@item -isync
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Synchronize read on input.
640
@end table
641

    
642
@section Advanced options
643

    
644
@table @option
645
@item -map @var{input_file_id}.@var{input_stream_id}[:@var{sync_file_id}.@var{sync_stream_id}]
646

    
647
Designate an input stream as a source for the output file. Each input
648
stream is identified by the input file index @var{input_file_id} and
649
the input stream index @var{input_stream_id} within the input
650
file. Both indexes start at 0. If specified,
651
@var{sync_file_id}.@var{sync_stream_id} sets which input stream
652
is used as a presentation sync reference.
653

    
654
The @code{-map} options must be specified just after the output file.
655
If any @code{-map} options are used, the number of @code{-map} options
656
on the command line must match the number of streams in the output
657
file. The first @code{-map} option on the command line specifies the
658
source for output stream 0, the second @code{-map} option specifies
659
the source for output stream 1, etc.
660

    
661
For example, if you have two audio streams in the first input file,
662
these streams are identified by "0.0" and "0.1". You can use
663
@code{-map} to select which stream to place in an output file. For
664
example:
665
@example
666
ffmpeg -i INPUT out.wav -map 0.1
667
@end example
668
will map the input stream in @file{INPUT} identified by "0.1" to
669
the (single) output stream in @file{out.wav}.
670

    
671
For example, to select the stream with index 2 from input file
672
@file{a.mov} (specified by the identifier "0.2"), and stream with
673
index 6 from input @file{b.mov} (specified by the identifier "1.6"),
674
and copy them to the output file @file{out.mov}:
675
@example
676
ffmpeg -i a.mov -i b.mov -vcodec copy -acodec copy out.mov -map 0.2 -map 1.6
677
@end example
678

    
679
To add more streams to the output file, you can use the
680
@code{-newaudio}, @code{-newvideo}, @code{-newsubtitle} options.
681

    
682
@item -map_meta_data @var{outfile}[,@var{metadata}]:@var{infile}[,@var{metadata}]
683
Deprecated, use @var{-map_metadata} instead.
684

    
685
@item -map_metadata @var{outfile}[,@var{metadata}]:@var{infile}[,@var{metadata}]
686
Set metadata information of @var{outfile} from @var{infile}. Note that those
687
are file indices (zero-based), not filenames.
688
Optional @var{metadata} parameters specify, which metadata to copy - (g)lobal
689
(i.e. metadata that applies to the whole file), per-(s)tream, per-(c)hapter or
690
per-(p)rogram. All metadata specifiers other than global must be followed by the
691
stream/chapter/program number. If metadata specifier is omitted, it defaults to
692
global.
693

    
694
By default, global metadata is copied from the first input file to all output files,
695
per-stream and per-chapter metadata is copied along with streams/chapters. These
696
default mappings are disabled by creating any mapping of the relevant type. A negative
697
file index can be used to create a dummy mapping that just disables automatic copying.
698

    
699
For example to copy metadata from the first stream of the input file to global metadata
700
of the output file:
701
@example
702
ffmpeg -i in.ogg -map_metadata 0:0,s0 out.mp3
703
@end example
704
@item -map_chapters @var{outfile}:@var{infile}
705
Copy chapters from @var{infile} to @var{outfile}. If no chapter mapping is specified,
706
then chapters are copied from the first input file with at least one chapter to all
707
output files. Use a negative file index to disable any chapter copying.
708
@item -debug
709
Print specific debug info.
710
@item -benchmark
711
Show benchmarking information at the end of an encode.
712
Shows CPU time used and maximum memory consumption.
713
Maximum memory consumption is not supported on all systems,
714
it will usually display as 0 if not supported.
715
@item -dump
716
Dump each input packet.
717
@item -hex
718
When dumping packets, also dump the payload.
719
@item -bitexact
720
Only use bit exact algorithms (for codec testing).
721
@item -ps @var{size}
722
Set RTP payload size in bytes.
723
@item -re
724
Read input at native frame rate. Mainly used to simulate a grab device.
725
@item -loop_input
726
Loop over the input stream. Currently it works only for image
727
streams. This option is used for automatic FFserver testing.
728
@item -loop_output @var{number_of_times}
729
Repeatedly loop output for formats that support looping such as animated GIF
730
(0 will loop the output infinitely).
731
@item -threads @var{count}
732
Thread count.
733
@item -vsync @var{parameter}
734
Video sync method.
735

    
736
@table @option
737
@item 0
738
Each frame is passed with its timestamp from the demuxer to the muxer.
739
@item 1
740
Frames will be duplicated and dropped to achieve exactly the requested
741
constant framerate.
742
@item 2
743
Frames are passed through with their timestamp or dropped so as to
744
prevent 2 frames from having the same timestamp.
745
@item -1
746
Chooses between 1 and 2 depending on muxer capabilities. This is the
747
default method.
748
@end table
749

    
750
With -map you can select from which stream the timestamps should be
751
taken. You can leave either video or audio unchanged and sync the
752
remaining stream(s) to the unchanged one.
753

    
754
@item -async @var{samples_per_second}
755
Audio sync method. "Stretches/squeezes" the audio stream to match the timestamps,
756
the parameter is the maximum samples per second by which the audio is changed.
757
-async 1 is a special case where only the start of the audio stream is corrected
758
without any later correction.
759
@item -copyts
760
Copy timestamps from input to output.
761
@item -copytb
762
Copy input stream time base from input to output when stream copying.
763
@item -shortest
764
Finish encoding when the shortest input stream ends.
765
@item -dts_delta_threshold
766
Timestamp discontinuity delta threshold.
767
@item -muxdelay @var{seconds}
768
Set the maximum demux-decode delay.
769
@item -muxpreload @var{seconds}
770
Set the initial demux-decode delay.
771
@item -streamid @var{output-stream-index}:@var{new-value}
772
Assign a new stream-id value to an output stream. This option should be
773
specified prior to the output filename to which it applies.
774
For the situation where multiple output files exist, a streamid
775
may be reassigned to a different value.
776

    
777
For example, to set the stream 0 PID to 33 and the stream 1 PID to 36 for
778
an output mpegts file:
779
@example
780
ffmpeg -i infile -streamid 0:33 -streamid 1:36 out.ts
781
@end example
782
@end table
783

    
784
@section Preset files
785

    
786
A preset file contains a sequence of @var{option}=@var{value} pairs,
787
one for each line, specifying a sequence of options which would be
788
awkward to specify on the command line. Lines starting with the hash
789
('#') character are ignored and are used to provide comments. Check
790
the @file{ffpresets} directory in the Libav source tree for examples.
791

    
792
Preset files are specified with the @code{vpre}, @code{apre},
793
@code{spre}, and @code{fpre} options. The @code{fpre} option takes the
794
filename of the preset instead of a preset name as input and can be
795
used for any kind of codec. For the @code{vpre}, @code{apre}, and
796
@code{spre} options, the options specified in a preset file are
797
applied to the currently selected codec of the same type as the preset
798
option.
799

    
800
The argument passed to the @code{vpre}, @code{apre}, and @code{spre}
801
preset options identifies the preset file to use according to the
802
following rules:
803

    
804
First ffmpeg searches for a file named @var{arg}.ffpreset in the
805
directories @file{$FFMPEG_DATADIR} (if set), and @file{$HOME/.ffmpeg}, and in
806
the datadir defined at configuration time (usually @file{PREFIX/share/ffmpeg})
807
in that order. For example, if the argument is @code{libx264-max}, it will
808
search for the file @file{libx264-max.ffpreset}.
809

    
810
If no such file is found, then ffmpeg will search for a file named
811
@var{codec_name}-@var{arg}.ffpreset in the above-mentioned
812
directories, where @var{codec_name} is the name of the codec to which
813
the preset file options will be applied. For example, if you select
814
the video codec with @code{-vcodec libx264} and use @code{-vpre max},
815
then it will search for the file @file{libx264-max.ffpreset}.
816
@c man end
817

    
818
@chapter Tips
819
@c man begin TIPS
820

    
821
@itemize
822
@item
823
For streaming at very low bitrate application, use a low frame rate
824
and a small GOP size. This is especially true for RealVideo where
825
the Linux player does not seem to be very fast, so it can miss
826
frames. An example is:
827

    
828
@example
829
ffmpeg -g 3 -r 3 -t 10 -b 50k -s qcif -f rv10 /tmp/b.rm
830
@end example
831

    
832
@item
833
The parameter 'q' which is displayed while encoding is the current
834
quantizer. The value 1 indicates that a very good quality could
835
be achieved. The value 31 indicates the worst quality. If q=31 appears
836
too often, it means that the encoder cannot compress enough to meet
837
your bitrate. You must either increase the bitrate, decrease the
838
frame rate or decrease the frame size.
839

    
840
@item
841
If your computer is not fast enough, you can speed up the
842
compression at the expense of the compression ratio. You can use
843
'-me zero' to speed up motion estimation, and '-intra' to disable
844
motion estimation completely (you have only I-frames, which means it
845
is about as good as JPEG compression).
846

    
847
@item
848
To have very low audio bitrates, reduce the sampling frequency
849
(down to 22050 Hz for MPEG audio, 22050 or 11025 for AC-3).
850

    
851
@item
852
To have a constant quality (but a variable bitrate), use the option
853
'-qscale n' when 'n' is between 1 (excellent quality) and 31 (worst
854
quality).
855

    
856
@item
857
When converting video files, you can use the '-sameq' option which
858
uses the same quality factor in the encoder as in the decoder.
859
It allows almost lossless encoding.
860

    
861
@end itemize
862
@c man end TIPS
863

    
864
@chapter Examples
865
@c man begin EXAMPLES
866

    
867
@section Video and Audio grabbing
868

    
869
If you specify the input format and device then ffmpeg can grab video
870
and audio directly.
871

    
872
@example
873
ffmpeg -f oss -i /dev/dsp -f video4linux2 -i /dev/video0 /tmp/out.mpg
874
@end example
875

    
876
Note that you must activate the right video source and channel before
877
launching ffmpeg with any TV viewer such as xawtv
878
(@url{http://linux.bytesex.org/xawtv/}) by Gerd Knorr. You also
879
have to set the audio recording levels correctly with a
880
standard mixer.
881

    
882
@section X11 grabbing
883

    
884
Grab the X11 display with ffmpeg via
885

    
886
@example
887
ffmpeg -f x11grab -s cif -r 25 -i :0.0 /tmp/out.mpg
888
@end example
889

    
890
0.0 is display.screen number of your X11 server, same as
891
the DISPLAY environment variable.
892

    
893
@example
894
ffmpeg -f x11grab -s cif -r 25 -i :0.0+10,20 /tmp/out.mpg
895
@end example
896

    
897
0.0 is display.screen number of your X11 server, same as the DISPLAY environment
898
variable. 10 is the x-offset and 20 the y-offset for the grabbing.
899

    
900
@section Video and Audio file format conversion
901

    
902
Any supported file format and protocol can serve as input to ffmpeg:
903

    
904
Examples:
905
@itemize
906
@item
907
You can use YUV files as input:
908

    
909
@example
910
ffmpeg -i /tmp/test%d.Y /tmp/out.mpg
911
@end example
912

    
913
It will use the files:
914
@example
915
/tmp/test0.Y, /tmp/test0.U, /tmp/test0.V,
916
/tmp/test1.Y, /tmp/test1.U, /tmp/test1.V, etc...
917
@end example
918

    
919
The Y files use twice the resolution of the U and V files. They are
920
raw files, without header. They can be generated by all decent video
921
decoders. You must specify the size of the image with the @option{-s} option
922
if ffmpeg cannot guess it.
923

    
924
@item
925
You can input from a raw YUV420P file:
926

    
927
@example
928
ffmpeg -i /tmp/test.yuv /tmp/out.avi
929
@end example
930

    
931
test.yuv is a file containing raw YUV planar data. Each frame is composed
932
of the Y plane followed by the U and V planes at half vertical and
933
horizontal resolution.
934

    
935
@item
936
You can output to a raw YUV420P file:
937

    
938
@example
939
ffmpeg -i mydivx.avi hugefile.yuv
940
@end example
941

    
942
@item
943
You can set several input files and output files:
944

    
945
@example
946
ffmpeg -i /tmp/a.wav -s 640x480 -i /tmp/a.yuv /tmp/a.mpg
947
@end example
948

    
949
Converts the audio file a.wav and the raw YUV video file a.yuv
950
to MPEG file a.mpg.
951

    
952
@item
953
You can also do audio and video conversions at the same time:
954

    
955
@example
956
ffmpeg -i /tmp/a.wav -ar 22050 /tmp/a.mp2
957
@end example
958

    
959
Converts a.wav to MPEG audio at 22050 Hz sample rate.
960

    
961
@item
962
You can encode to several formats at the same time and define a
963
mapping from input stream to output streams:
964

    
965
@example
966
ffmpeg -i /tmp/a.wav -ab 64k /tmp/a.mp2 -ab 128k /tmp/b.mp2 -map 0:0 -map 0:0
967
@end example
968

    
969
Converts a.wav to a.mp2 at 64 kbits and to b.mp2 at 128 kbits. '-map
970
file:index' specifies which input stream is used for each output
971
stream, in the order of the definition of output streams.
972

    
973
@item
974
You can transcode decrypted VOBs:
975

    
976
@example
977
ffmpeg -i snatch_1.vob -f avi -vcodec mpeg4 -b 800k -g 300 -bf 2 -acodec libmp3lame -ab 128k snatch.avi
978
@end example
979

    
980
This is a typical DVD ripping example; the input is a VOB file, the
981
output an AVI file with MPEG-4 video and MP3 audio. Note that in this
982
command we use B-frames so the MPEG-4 stream is DivX5 compatible, and
983
GOP size is 300 which means one intra frame every 10 seconds for 29.97fps
984
input video. Furthermore, the audio stream is MP3-encoded so you need
985
to enable LAME support by passing @code{--enable-libmp3lame} to configure.
986
The mapping is particularly useful for DVD transcoding
987
to get the desired audio language.
988

    
989
NOTE: To see the supported input formats, use @code{ffmpeg -formats}.
990

    
991
@item
992
You can extract images from a video, or create a video from many images:
993

    
994
For extracting images from a video:
995
@example
996
ffmpeg -i foo.avi -r 1 -s WxH -f image2 foo-%03d.jpeg
997
@end example
998

    
999
This will extract one video frame per second from the video and will
1000
output them in files named @file{foo-001.jpeg}, @file{foo-002.jpeg},
1001
etc. Images will be rescaled to fit the new WxH values.
1002

    
1003
If you want to extract just a limited number of frames, you can use the
1004
above command in combination with the -vframes or -t option, or in
1005
combination with -ss to start extracting from a certain point in time.
1006

    
1007
For creating a video from many images:
1008
@example
1009
ffmpeg -f image2 -i foo-%03d.jpeg -r 12 -s WxH foo.avi
1010
@end example
1011

    
1012
The syntax @code{foo-%03d.jpeg} specifies to use a decimal number
1013
composed of three digits padded with zeroes to express the sequence
1014
number. It is the same syntax supported by the C printf function, but
1015
only formats accepting a normal integer are suitable.
1016

    
1017
@item
1018
You can put many streams of the same type in the output:
1019

    
1020
@example
1021
ffmpeg -i test1.avi -i test2.avi -vcodec copy -acodec copy -vcodec copy -acodec copy test12.avi -newvideo -newaudio
1022
@end example
1023

    
1024
In addition to the first video and audio streams, the resulting
1025
output file @file{test12.avi} will contain the second video
1026
and the second audio stream found in the input streams list.
1027

    
1028
The @code{-newvideo}, @code{-newaudio} and @code{-newsubtitle}
1029
options have to be specified immediately after the name of the output
1030
file to which you want to add them.
1031

    
1032
@end itemize
1033
@c man end EXAMPLES
1034

    
1035
@include eval.texi
1036
@include encoders.texi
1037
@include demuxers.texi
1038
@include muxers.texi
1039
@include indevs.texi
1040
@include outdevs.texi
1041
@include protocols.texi
1042
@include bitstream_filters.texi
1043
@include filters.texi
1044
@include metadata.texi
1045

    
1046
@ignore
1047

    
1048
@setfilename ffmpeg
1049
@settitle ffmpeg video converter
1050

    
1051
@c man begin SEEALSO
1052
ffplay(1), ffprobe(1), ffserver(1) and the Libav HTML documentation
1053
@c man end
1054

    
1055
@c man begin AUTHORS
1056
The Libav developers
1057
@c man end
1058

    
1059
@end ignore
1060

    
1061
@bye