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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. 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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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
631
@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
641
Synchronize read on input.
642
@end table
643

    
644
@section Advanced options
645

    
646
@table @option
647
@item -map @var{input_file_id}.@var{input_stream_id}[:@var{sync_file_id}.@var{sync_stream_id}]
648

    
649
Designate an input stream as a source for the output file. Each input
650
stream is identified by the input file index @var{input_file_id} and
651
the input stream index @var{input_stream_id} within the input
652
file. Both indexes start at 0. If specified,
653
@var{sync_file_id}.@var{sync_stream_id} sets which input stream
654
is used as a presentation sync reference.
655

    
656
The @code{-map} options must be specified just after the output file.
657
If any @code{-map} options are used, the number of @code{-map} options
658
on the command line must match the number of streams in the output
659
file. The first @code{-map} option on the command line specifies the
660
source for output stream 0, the second @code{-map} option specifies
661
the source for output stream 1, etc.
662

    
663
For example, if you have two audio streams in the first input file,
664
these streams are identified by "0.0" and "0.1". You can use
665
@code{-map} to select which stream to place in an output file. For
666
example:
667
@example
668
ffmpeg -i INPUT out.wav -map 0.1
669
@end example
670
will map the input stream in @file{INPUT} identified by "0.1" to
671
the (single) output stream in @file{out.wav}.
672

    
673
For example, to select the stream with index 2 from input file
674
@file{a.mov} (specified by the identifier "0.2"), and stream with
675
index 6 from input @file{b.mov} (specified by the identifier "1.6"),
676
and copy them to the output file @file{out.mov}:
677
@example
678
ffmpeg -i a.mov -i b.mov -vcodec copy -acodec copy out.mov -map 0.2 -map 1.6
679
@end example
680

    
681
To add more streams to the output file, you can use the
682
@code{-newaudio}, @code{-newvideo}, @code{-newsubtitle} options.
683

    
684
@item -map_meta_data @var{outfile}[,@var{metadata}]:@var{infile}[,@var{metadata}]
685
Deprecated, use @var{-map_metadata} instead.
686

    
687
@item -map_metadata @var{outfile}[,@var{metadata}]:@var{infile}[,@var{metadata}]
688
Set metadata information of @var{outfile} from @var{infile}. Note that those
689
are file indices (zero-based), not filenames.
690
Optional @var{metadata} parameters specify, which metadata to copy - (g)lobal
691
(i.e. metadata that applies to the whole file), per-(s)tream, per-(c)hapter or
692
per-(p)rogram. All metadata specifiers other than global must be followed by the
693
stream/chapter/program number. If metadata specifier is omitted, it defaults to
694
global.
695

    
696
By default, global metadata is copied from the first input file to all output files,
697
per-stream and per-chapter metadata is copied along with streams/chapters. These
698
default mappings are disabled by creating any mapping of the relevant type. A negative
699
file index can be used to create a dummy mapping that just disables automatic copying.
700

    
701
For example to copy metadata from the first stream of the input file to global metadata
702
of the output file:
703
@example
704
ffmpeg -i in.ogg -map_metadata 0:0,s0 out.mp3
705
@end example
706
@item -map_chapters @var{outfile}:@var{infile}
707
Copy chapters from @var{infile} to @var{outfile}. If no chapter mapping is specified,
708
then chapters are copied from the first input file with at least one chapter to all
709
output files. Use a negative file index to disable any chapter copying.
710
@item -debug
711
Print specific debug info.
712
@item -benchmark
713
Show benchmarking information at the end of an encode.
714
Shows CPU time used and maximum memory consumption.
715
Maximum memory consumption is not supported on all systems,
716
it will usually display as 0 if not supported.
717
@item -dump
718
Dump each input packet.
719
@item -hex
720
When dumping packets, also dump the payload.
721
@item -bitexact
722
Only use bit exact algorithms (for codec testing).
723
@item -ps @var{size}
724
Set RTP payload size in bytes.
725
@item -re
726
Read input at native frame rate. Mainly used to simulate a grab device.
727
@item -loop_input
728
Loop over the input stream. Currently it works only for image
729
streams. This option is used for automatic FFserver testing.
730
@item -loop_output @var{number_of_times}
731
Repeatedly loop output for formats that support looping such as animated GIF
732
(0 will loop the output infinitely).
733
@item -threads @var{count}
734
Thread count.
735
@item -vsync @var{parameter}
736
Video sync method.
737

    
738
@table @option
739
@item 0
740
Each frame is passed with its timestamp from the demuxer to the muxer.
741
@item 1
742
Frames will be duplicated and dropped to achieve exactly the requested
743
constant framerate.
744
@item 2
745
Frames are passed through with their timestamp or dropped so as to
746
prevent 2 frames from having the same timestamp.
747
@item -1
748
Chooses between 1 and 2 depending on muxer capabilities. This is the
749
default method.
750
@end table
751

    
752
With -map you can select from which stream the timestamps should be
753
taken. You can leave either video or audio unchanged and sync the
754
remaining stream(s) to the unchanged one.
755

    
756
@item -async @var{samples_per_second}
757
Audio sync method. "Stretches/squeezes" the audio stream to match the timestamps,
758
the parameter is the maximum samples per second by which the audio is changed.
759
-async 1 is a special case where only the start of the audio stream is corrected
760
without any later correction.
761
@item -copyts
762
Copy timestamps from input to output.
763
@item -copytb
764
Copy input stream time base from input to output when stream copying.
765
@item -shortest
766
Finish encoding when the shortest input stream ends.
767
@item -dts_delta_threshold
768
Timestamp discontinuity delta threshold.
769
@item -muxdelay @var{seconds}
770
Set the maximum demux-decode delay.
771
@item -muxpreload @var{seconds}
772
Set the initial demux-decode delay.
773
@item -streamid @var{output-stream-index}:@var{new-value}
774
Assign a new stream-id value to an output stream. This option should be
775
specified prior to the output filename to which it applies.
776
For the situation where multiple output files exist, a streamid
777
may be reassigned to a different value.
778

    
779
For example, to set the stream 0 PID to 33 and the stream 1 PID to 36 for
780
an output mpegts file:
781
@example
782
ffmpeg -i infile -streamid 0:33 -streamid 1:36 out.ts
783
@end example
784
@end table
785

    
786
@section Preset files
787

    
788
A preset file contains a sequence of @var{option}=@var{value} pairs,
789
one for each line, specifying a sequence of options which would be
790
awkward to specify on the command line. Lines starting with the hash
791
('#') character are ignored and are used to provide comments. Check
792
the @file{ffpresets} directory in the Libav source tree for examples.
793

    
794
Preset files are specified with the @code{vpre}, @code{apre},
795
@code{spre}, and @code{fpre} options. The @code{fpre} option takes the
796
filename of the preset instead of a preset name as input and can be
797
used for any kind of codec. For the @code{vpre}, @code{apre}, and
798
@code{spre} options, the options specified in a preset file are
799
applied to the currently selected codec of the same type as the preset
800
option.
801

    
802
The argument passed to the @code{vpre}, @code{apre}, and @code{spre}
803
preset options identifies the preset file to use according to the
804
following rules:
805

    
806
First ffmpeg searches for a file named @var{arg}.ffpreset in the
807
directories @file{$FFMPEG_DATADIR} (if set), and @file{$HOME/.ffmpeg}, and in
808
the datadir defined at configuration time (usually @file{PREFIX/share/ffmpeg})
809
in that order. For example, if the argument is @code{libx264-max}, it will
810
search for the file @file{libx264-max.ffpreset}.
811

    
812
If no such file is found, then ffmpeg will search for a file named
813
@var{codec_name}-@var{arg}.ffpreset in the above-mentioned
814
directories, where @var{codec_name} is the name of the codec to which
815
the preset file options will be applied. For example, if you select
816
the video codec with @code{-vcodec libx264} and use @code{-vpre max},
817
then it will search for the file @file{libx264-max.ffpreset}.
818
@c man end
819

    
820
@chapter Tips
821
@c man begin TIPS
822

    
823
@itemize
824
@item
825
For streaming at very low bitrate application, use a low frame rate
826
and a small GOP size. This is especially true for RealVideo where
827
the Linux player does not seem to be very fast, so it can miss
828
frames. An example is:
829

    
830
@example
831
ffmpeg -g 3 -r 3 -t 10 -b 50k -s qcif -f rv10 /tmp/b.rm
832
@end example
833

    
834
@item
835
The parameter 'q' which is displayed while encoding is the current
836
quantizer. The value 1 indicates that a very good quality could
837
be achieved. The value 31 indicates the worst quality. If q=31 appears
838
too often, it means that the encoder cannot compress enough to meet
839
your bitrate. You must either increase the bitrate, decrease the
840
frame rate or decrease the frame size.
841

    
842
@item
843
If your computer is not fast enough, you can speed up the
844
compression at the expense of the compression ratio. You can use
845
'-me zero' to speed up motion estimation, and '-intra' to disable
846
motion estimation completely (you have only I-frames, which means it
847
is about as good as JPEG compression).
848

    
849
@item
850
To have very low audio bitrates, reduce the sampling frequency
851
(down to 22050 Hz for MPEG audio, 22050 or 11025 for AC-3).
852

    
853
@item
854
To have a constant quality (but a variable bitrate), use the option
855
'-qscale n' when 'n' is between 1 (excellent quality) and 31 (worst
856
quality).
857

    
858
@item
859
When converting video files, you can use the '-sameq' option which
860
uses the same quality factor in the encoder as in the decoder.
861
It allows almost lossless encoding.
862

    
863
@end itemize
864
@c man end TIPS
865

    
866
@chapter Examples
867
@c man begin EXAMPLES
868

    
869
@section Video and Audio grabbing
870

    
871
FFmpeg can grab video and audio from devices given that you specify the input
872
format and device.
873

    
874
@example
875
ffmpeg -f oss -i /dev/dsp -f video4linux2 -i /dev/video0 /tmp/out.mpg
876
@end example
877

    
878
Note that you must activate the right video source and channel before
879
launching FFmpeg with any TV viewer such as xawtv
880
(@url{http://linux.bytesex.org/xawtv/}) by Gerd Knorr. You also
881
have to set the audio recording levels correctly with a
882
standard mixer.
883

    
884
@section X11 grabbing
885

    
886
FFmpeg can grab the X11 display.
887

    
888
@example
889
ffmpeg -f x11grab -s cif -r 25 -i :0.0 /tmp/out.mpg
890
@end example
891

    
892
0.0 is display.screen number of your X11 server, same as
893
the DISPLAY environment variable.
894

    
895
@example
896
ffmpeg -f x11grab -s cif -r 25 -i :0.0+10,20 /tmp/out.mpg
897
@end example
898

    
899
0.0 is display.screen number of your X11 server, same as the DISPLAY environment
900
variable. 10 is the x-offset and 20 the y-offset for the grabbing.
901

    
902
@section Video and Audio file format conversion
903

    
904
FFmpeg can use any supported file format and protocol as input:
905

    
906
Examples:
907
@itemize
908
@item
909
You can use YUV files as input:
910

    
911
@example
912
ffmpeg -i /tmp/test%d.Y /tmp/out.mpg
913
@end example
914

    
915
It will use the files:
916
@example
917
/tmp/test0.Y, /tmp/test0.U, /tmp/test0.V,
918
/tmp/test1.Y, /tmp/test1.U, /tmp/test1.V, etc...
919
@end example
920

    
921
The Y files use twice the resolution of the U and V files. They are
922
raw files, without header. They can be generated by all decent video
923
decoders. You must specify the size of the image with the @option{-s} option
924
if FFmpeg cannot guess it.
925

    
926
@item
927
You can input from a raw YUV420P file:
928

    
929
@example
930
ffmpeg -i /tmp/test.yuv /tmp/out.avi
931
@end example
932

    
933
test.yuv is a file containing raw YUV planar data. Each frame is composed
934
of the Y plane followed by the U and V planes at half vertical and
935
horizontal resolution.
936

    
937
@item
938
You can output to a raw YUV420P file:
939

    
940
@example
941
ffmpeg -i mydivx.avi hugefile.yuv
942
@end example
943

    
944
@item
945
You can set several input files and output files:
946

    
947
@example
948
ffmpeg -i /tmp/a.wav -s 640x480 -i /tmp/a.yuv /tmp/a.mpg
949
@end example
950

    
951
Converts the audio file a.wav and the raw YUV video file a.yuv
952
to MPEG file a.mpg.
953

    
954
@item
955
You can also do audio and video conversions at the same time:
956

    
957
@example
958
ffmpeg -i /tmp/a.wav -ar 22050 /tmp/a.mp2
959
@end example
960

    
961
Converts a.wav to MPEG audio at 22050 Hz sample rate.
962

    
963
@item
964
You can encode to several formats at the same time and define a
965
mapping from input stream to output streams:
966

    
967
@example
968
ffmpeg -i /tmp/a.wav -ab 64k /tmp/a.mp2 -ab 128k /tmp/b.mp2 -map 0:0 -map 0:0
969
@end example
970

    
971
Converts a.wav to a.mp2 at 64 kbits and to b.mp2 at 128 kbits. '-map
972
file:index' specifies which input stream is used for each output
973
stream, in the order of the definition of output streams.
974

    
975
@item
976
You can transcode decrypted VOBs:
977

    
978
@example
979
ffmpeg -i snatch_1.vob -f avi -vcodec mpeg4 -b 800k -g 300 -bf 2 -acodec libmp3lame -ab 128k snatch.avi
980
@end example
981

    
982
This is a typical DVD ripping example; the input is a VOB file, the
983
output an AVI file with MPEG-4 video and MP3 audio. Note that in this
984
command we use B-frames so the MPEG-4 stream is DivX5 compatible, and
985
GOP size is 300 which means one intra frame every 10 seconds for 29.97fps
986
input video. Furthermore, the audio stream is MP3-encoded so you need
987
to enable LAME support by passing @code{--enable-libmp3lame} to configure.
988
The mapping is particularly useful for DVD transcoding
989
to get the desired audio language.
990

    
991
NOTE: To see the supported input formats, use @code{ffmpeg -formats}.
992

    
993
@item
994
You can extract images from a video, or create a video from many images:
995

    
996
For extracting images from a video:
997
@example
998
ffmpeg -i foo.avi -r 1 -s WxH -f image2 foo-%03d.jpeg
999
@end example
1000

    
1001
This will extract one video frame per second from the video and will
1002
output them in files named @file{foo-001.jpeg}, @file{foo-002.jpeg},
1003
etc. Images will be rescaled to fit the new WxH values.
1004

    
1005
If you want to extract just a limited number of frames, you can use the
1006
above command in combination with the -vframes or -t option, or in
1007
combination with -ss to start extracting from a certain point in time.
1008

    
1009
For creating a video from many images:
1010
@example
1011
ffmpeg -f image2 -i foo-%03d.jpeg -r 12 -s WxH foo.avi
1012
@end example
1013

    
1014
The syntax @code{foo-%03d.jpeg} specifies to use a decimal number
1015
composed of three digits padded with zeroes to express the sequence
1016
number. It is the same syntax supported by the C printf function, but
1017
only formats accepting a normal integer are suitable.
1018

    
1019
@item
1020
You can put many streams of the same type in the output:
1021

    
1022
@example
1023
ffmpeg -i test1.avi -i test2.avi -vcodec copy -acodec copy -vcodec copy -acodec copy test12.avi -newvideo -newaudio
1024
@end example
1025

    
1026
In addition to the first video and audio streams, the resulting
1027
output file @file{test12.avi} will contain the second video
1028
and the second audio stream found in the input streams list.
1029

    
1030
The @code{-newvideo}, @code{-newaudio} and @code{-newsubtitle}
1031
options have to be specified immediately after the name of the output
1032
file to which you want to add them.
1033

    
1034
@end itemize
1035
@c man end EXAMPLES
1036

    
1037
@include eval.texi
1038
@include encoders.texi
1039
@include demuxers.texi
1040
@include muxers.texi
1041
@include indevs.texi
1042
@include outdevs.texi
1043
@include protocols.texi
1044
@include bitstream_filters.texi
1045
@include filters.texi
1046
@include metadata.texi
1047

    
1048
@ignore
1049

    
1050
@setfilename ffmpeg
1051
@settitle FFmpeg video converter
1052

    
1053
@c man begin SEEALSO
1054
ffplay(1), ffprobe(1), ffserver(1) and the Libav HTML documentation
1055
@c man end
1056

    
1057
@c man begin AUTHORS
1058
The Libav developers
1059
@c man end
1060

    
1061
@end ignore
1062

    
1063
@bye