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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 video quality 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 -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
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@end table
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@section Audio/Video grab options
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@table @option
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@item -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.
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@end table
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@section Advanced options
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@table @option
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@item -map @var{input_stream_id}[:@var{sync_stream_id}]
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Set stream mapping from input streams to output streams.
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Just enumerate the input streams in the order you want them in the output.
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@var{sync_stream_id} if specified sets the input stream to sync
629
against.
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@item -map_meta_data @var{outfile}[,@var{metadata}]:@var{infile}[,@var{metadata}]
631
Deprecated, use @var{-map_metadata} instead.
632

    
633
@item -map_metadata @var{outfile}[,@var{metadata}]:@var{infile}[,@var{metadata}]
634
Set metadata information of @var{outfile} from @var{infile}. Note that those
635
are file indices (zero-based), not filenames.
636
Optional @var{metadata} parameters specify, which metadata to copy - (g)lobal
637
(i.e. metadata that applies to the whole file), per-(s)tream, per-(c)hapter or
638
per-(p)rogram. All metadata specifiers other than global must be followed by the
639
stream/chapter/program number. If metadata specifier is omitted, it defaults to
640
global.
641

    
642
By default, global metadata is copied from the first input file to all output files,
643
per-stream and per-chapter metadata is copied along with streams/chapters. These
644
default mappings are disabled by creating any mapping of the relevant type. A negative
645
file index can be used to create a dummy mapping that just disables automatic copying.
646

    
647
For example to copy metadata from the first stream of the input file to global metadata
648
of the output file:
649
@example
650
ffmpeg -i in.ogg -map_metadata 0:0,s0 out.mp3
651
@end example
652
@item -map_chapters @var{outfile}:@var{infile}
653
Copy chapters from @var{infile} to @var{outfile}. If no chapter mapping is specified,
654
then chapters are copied from the first input file with at least one chapter to all
655
output files. Use a negative file index to disable any chapter copying.
656
@item -debug
657
Print specific debug info.
658
@item -benchmark
659
Show benchmarking information at the end of an encode.
660
Shows CPU time used and maximum memory consumption.
661
Maximum memory consumption is not supported on all systems,
662
it will usually display as 0 if not supported.
663
@item -dump
664
Dump each input packet.
665
@item -hex
666
When dumping packets, also dump the payload.
667
@item -bitexact
668
Only use bit exact algorithms (for codec testing).
669
@item -ps @var{size}
670
Set RTP payload size in bytes.
671
@item -re
672
Read input at native frame rate. Mainly used to simulate a grab device.
673
@item -loop_input
674
Loop over the input stream. Currently it works only for image
675
streams. This option is used for automatic FFserver testing.
676
@item -loop_output @var{number_of_times}
677
Repeatedly loop output for formats that support looping such as animated GIF
678
(0 will loop the output infinitely).
679
@item -threads @var{count}
680
Thread count.
681
@item -vsync @var{parameter}
682
Video sync method.
683

    
684
@table @option
685
@item 0
686
Each frame is passed with its timestamp from the demuxer to the muxer.
687
@item 1
688
Frames will be duplicated and dropped to achieve exactly the requested
689
constant framerate.
690
@item 2
691
Frames are passed through with their timestamp or dropped so as to
692
prevent 2 frames from having the same timestamp.
693
@item -1
694
Chooses between 1 and 2 depending on muxer capabilities. This is the
695
default method.
696
@end table
697

    
698
With -map you can select from which stream the timestamps should be
699
taken. You can leave either video or audio unchanged and sync the
700
remaining stream(s) to the unchanged one.
701

    
702
@item -async @var{samples_per_second}
703
Audio sync method. "Stretches/squeezes" the audio stream to match the timestamps,
704
the parameter is the maximum samples per second by which the audio is changed.
705
-async 1 is a special case where only the start of the audio stream is corrected
706
without any later correction.
707
@item -copyts
708
Copy timestamps from input to output.
709
@item -copytb
710
Copy input stream time base from input to output when stream copying.
711
@item -shortest
712
Finish encoding when the shortest input stream ends.
713
@item -dts_delta_threshold
714
Timestamp discontinuity delta threshold.
715
@item -muxdelay @var{seconds}
716
Set the maximum demux-decode delay.
717
@item -muxpreload @var{seconds}
718
Set the initial demux-decode delay.
719
@item -streamid @var{output-stream-index}:@var{new-value}
720
Assign a new stream-id value to an output stream. This option should be
721
specified prior to the output filename to which it applies.
722
For the situation where multiple output files exist, a streamid
723
may be reassigned to a different value.
724

    
725
For example, to set the stream 0 PID to 33 and the stream 1 PID to 36 for
726
an output mpegts file:
727
@example
728
ffmpeg -i infile -streamid 0:33 -streamid 1:36 out.ts
729
@end example
730
@end table
731

    
732
@section Preset files
733

    
734
A preset file contains a sequence of @var{option}=@var{value} pairs,
735
one for each line, specifying a sequence of options which would be
736
awkward to specify on the command line. Lines starting with the hash
737
('#') character are ignored and are used to provide comments. Check
738
the @file{ffpresets} directory in the FFmpeg source tree for examples.
739

    
740
Preset files are specified with the @code{vpre}, @code{apre},
741
@code{spre}, and @code{fpre} options. The @code{fpre} option takes the
742
filename of the preset instead of a preset name as input and can be
743
used for any kind of codec. For the @code{vpre}, @code{apre}, and
744
@code{spre} options, the options specified in a preset file are
745
applied to the currently selected codec of the same type as the preset
746
option.
747

    
748
The argument passed to the @code{vpre}, @code{apre}, and @code{spre}
749
preset options identifies the preset file to use according to the
750
following rules:
751

    
752
First ffmpeg searches for a file named @var{arg}.ffpreset in the
753
directories @file{$FFMPEG_DATADIR} (if set), and @file{$HOME/.ffmpeg}, and in
754
the datadir defined at configuration time (usually @file{PREFIX/share/ffmpeg})
755
in that order. For example, if the argument is @code{libx264-max}, it will
756
search for the file @file{libx264-max.ffpreset}.
757

    
758
If no such file is found, then ffmpeg will search for a file named
759
@var{codec_name}-@var{arg}.ffpreset in the above-mentioned
760
directories, where @var{codec_name} is the name of the codec to which
761
the preset file options will be applied. For example, if you select
762
the video codec with @code{-vcodec libx264} and use @code{-vpre max},
763
then it will search for the file @file{libx264-max.ffpreset}.
764
@c man end
765

    
766
@chapter Tips
767
@c man begin TIPS
768

    
769
@itemize
770
@item
771
For streaming at very low bitrate application, use a low frame rate
772
and a small GOP size. This is especially true for RealVideo where
773
the Linux player does not seem to be very fast, so it can miss
774
frames. An example is:
775

    
776
@example
777
ffmpeg -g 3 -r 3 -t 10 -b 50k -s qcif -f rv10 /tmp/b.rm
778
@end example
779

    
780
@item
781
The parameter 'q' which is displayed while encoding is the current
782
quantizer. The value 1 indicates that a very good quality could
783
be achieved. The value 31 indicates the worst quality. If q=31 appears
784
too often, it means that the encoder cannot compress enough to meet
785
your bitrate. You must either increase the bitrate, decrease the
786
frame rate or decrease the frame size.
787

    
788
@item
789
If your computer is not fast enough, you can speed up the
790
compression at the expense of the compression ratio. You can use
791
'-me zero' to speed up motion estimation, and '-intra' to disable
792
motion estimation completely (you have only I-frames, which means it
793
is about as good as JPEG compression).
794

    
795
@item
796
To have very low audio bitrates, reduce the sampling frequency
797
(down to 22050 Hz for MPEG audio, 22050 or 11025 for AC-3).
798

    
799
@item
800
To have a constant quality (but a variable bitrate), use the option
801
'-qscale n' when 'n' is between 1 (excellent quality) and 31 (worst
802
quality).
803

    
804
@item
805
When converting video files, you can use the '-sameq' option which
806
uses the same quality factor in the encoder as in the decoder.
807
It allows almost lossless encoding.
808

    
809
@end itemize
810
@c man end TIPS
811

    
812
@chapter Examples
813
@c man begin EXAMPLES
814

    
815
@section Video and Audio grabbing
816

    
817
FFmpeg can grab video and audio from devices given that you specify the input
818
format and device.
819

    
820
@example
821
ffmpeg -f oss -i /dev/dsp -f video4linux2 -i /dev/video0 /tmp/out.mpg
822
@end example
823

    
824
Note that you must activate the right video source and channel before
825
launching FFmpeg with any TV viewer such as xawtv
826
(@url{http://linux.bytesex.org/xawtv/}) by Gerd Knorr. You also
827
have to set the audio recording levels correctly with a
828
standard mixer.
829

    
830
@section X11 grabbing
831

    
832
FFmpeg can grab the X11 display.
833

    
834
@example
835
ffmpeg -f x11grab -s cif -r 25 -i :0.0 /tmp/out.mpg
836
@end example
837

    
838
0.0 is display.screen number of your X11 server, same as
839
the DISPLAY environment variable.
840

    
841
@example
842
ffmpeg -f x11grab -s cif -r 25 -i :0.0+10,20 /tmp/out.mpg
843
@end example
844

    
845
0.0 is display.screen number of your X11 server, same as the DISPLAY environment
846
variable. 10 is the x-offset and 20 the y-offset for the grabbing.
847

    
848
@section Video and Audio file format conversion
849

    
850
FFmpeg can use any supported file format and protocol as input:
851

    
852
Examples:
853
@itemize
854
@item
855
You can use YUV files as input:
856

    
857
@example
858
ffmpeg -i /tmp/test%d.Y /tmp/out.mpg
859
@end example
860

    
861
It will use the files:
862
@example
863
/tmp/test0.Y, /tmp/test0.U, /tmp/test0.V,
864
/tmp/test1.Y, /tmp/test1.U, /tmp/test1.V, etc...
865
@end example
866

    
867
The Y files use twice the resolution of the U and V files. They are
868
raw files, without header. They can be generated by all decent video
869
decoders. You must specify the size of the image with the @option{-s} option
870
if FFmpeg cannot guess it.
871

    
872
@item
873
You can input from a raw YUV420P file:
874

    
875
@example
876
ffmpeg -i /tmp/test.yuv /tmp/out.avi
877
@end example
878

    
879
test.yuv is a file containing raw YUV planar data. Each frame is composed
880
of the Y plane followed by the U and V planes at half vertical and
881
horizontal resolution.
882

    
883
@item
884
You can output to a raw YUV420P file:
885

    
886
@example
887
ffmpeg -i mydivx.avi hugefile.yuv
888
@end example
889

    
890
@item
891
You can set several input files and output files:
892

    
893
@example
894
ffmpeg -i /tmp/a.wav -s 640x480 -i /tmp/a.yuv /tmp/a.mpg
895
@end example
896

    
897
Converts the audio file a.wav and the raw YUV video file a.yuv
898
to MPEG file a.mpg.
899

    
900
@item
901
You can also do audio and video conversions at the same time:
902

    
903
@example
904
ffmpeg -i /tmp/a.wav -ar 22050 /tmp/a.mp2
905
@end example
906

    
907
Converts a.wav to MPEG audio at 22050 Hz sample rate.
908

    
909
@item
910
You can encode to several formats at the same time and define a
911
mapping from input stream to output streams:
912

    
913
@example
914
ffmpeg -i /tmp/a.wav -ab 64k /tmp/a.mp2 -ab 128k /tmp/b.mp2 -map 0:0 -map 0:0
915
@end example
916

    
917
Converts a.wav to a.mp2 at 64 kbits and to b.mp2 at 128 kbits. '-map
918
file:index' specifies which input stream is used for each output
919
stream, in the order of the definition of output streams.
920

    
921
@item
922
You can transcode decrypted VOBs:
923

    
924
@example
925
ffmpeg -i snatch_1.vob -f avi -vcodec mpeg4 -b 800k -g 300 -bf 2 -acodec libmp3lame -ab 128k snatch.avi
926
@end example
927

    
928
This is a typical DVD ripping example; the input is a VOB file, the
929
output an AVI file with MPEG-4 video and MP3 audio. Note that in this
930
command we use B-frames so the MPEG-4 stream is DivX5 compatible, and
931
GOP size is 300 which means one intra frame every 10 seconds for 29.97fps
932
input video. Furthermore, the audio stream is MP3-encoded so you need
933
to enable LAME support by passing @code{--enable-libmp3lame} to configure.
934
The mapping is particularly useful for DVD transcoding
935
to get the desired audio language.
936

    
937
NOTE: To see the supported input formats, use @code{ffmpeg -formats}.
938

    
939
@item
940
You can extract images from a video, or create a video from many images:
941

    
942
For extracting images from a video:
943
@example
944
ffmpeg -i foo.avi -r 1 -s WxH -f image2 foo-%03d.jpeg
945
@end example
946

    
947
This will extract one video frame per second from the video and will
948
output them in files named @file{foo-001.jpeg}, @file{foo-002.jpeg},
949
etc. Images will be rescaled to fit the new WxH values.
950

    
951
If you want to extract just a limited number of frames, you can use the
952
above command in combination with the -vframes or -t option, or in
953
combination with -ss to start extracting from a certain point in time.
954

    
955
For creating a video from many images:
956
@example
957
ffmpeg -f image2 -i foo-%03d.jpeg -r 12 -s WxH foo.avi
958
@end example
959

    
960
The syntax @code{foo-%03d.jpeg} specifies to use a decimal number
961
composed of three digits padded with zeroes to express the sequence
962
number. It is the same syntax supported by the C printf function, but
963
only formats accepting a normal integer are suitable.
964

    
965
@item
966
You can put many streams of the same type in the output:
967

    
968
@example
969
ffmpeg -i test1.avi -i test2.avi -vcodec copy -acodec copy -vcodec copy -acodec copy test12.avi -newvideo -newaudio
970
@end example
971

    
972
In addition to the first video and audio streams, the resulting
973
output file @file{test12.avi} will contain the second video
974
and the second audio stream found in the input streams list.
975

    
976
The @code{-newvideo}, @code{-newaudio} and @code{-newsubtitle}
977
options have to be specified immediately after the name of the output
978
file to which you want to add them.
979

    
980
@end itemize
981
@c man end EXAMPLES
982

    
983
@include eval.texi
984
@include encoders.texi
985
@include demuxers.texi
986
@include muxers.texi
987
@include indevs.texi
988
@include outdevs.texi
989
@include protocols.texi
990
@include bitstream_filters.texi
991
@include filters.texi
992
@include metadata.texi
993

    
994
@ignore
995

    
996
@setfilename ffmpeg
997
@settitle FFmpeg video converter
998

    
999
@c man begin SEEALSO
1000
ffplay(1), ffprobe(1), ffserver(1) and the FFmpeg HTML documentation
1001
@c man end
1002

    
1003
@c man begin AUTHORS
1004
The FFmpeg developers
1005
@c man end
1006

    
1007
@end ignore
1008

    
1009
@bye