mirror of https://git.ffmpeg.org/ffmpeg.git
doc/encoders: partially rewrite and reformat libx264 docs
Format is based on the thread: "[PATCH] doc/encoders: Add libopus encoder doc" (06-28-2013) http://thread.gmane.org/gmane.comp.video.ffmpeg.devel/165368/ Also merge the two option sections (Mapping and Private options). Patch partially edited by Stefano Sabatini. Signed-off-by: Stefano Sabatini <stefasab@gmail.com>
This commit is contained in:
Timothy Gu
Stefano Sabatini
parent
c5f3cc40e3
commit
11cb697501
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@ -873,178 +873,318 @@ For more information about libvpx see:
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x264 H.264/MPEG-4 AVC encoder wrapper.
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Requires the presence of the libx264 headers and library during
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configuration. You need to explicitly configure the build with
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This encoder requires the presence of the libx264 headers and library
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during configuration. You need to explicitly configure the build with
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@code{--enable-libx264}.
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x264 supports an impressive number of features, including 8x8 and 4x4 adaptive
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spatial transform, adaptive B-frame placement, CAVLC/CABAC entropy coding,
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interlacing (MBAFF), lossless mode, psy optimizations for detail retention
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(adaptive quantization, psy-RD, psy-trellis).
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libx264 supports an impressive number of features, including 8x8 and
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4x4 adaptive spatial transform, adaptive B-frame placement, CAVLC/CABAC
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entropy coding, interlacing (MBAFF), lossless mode, psy optimizations
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for detail retention (adaptive quantization, psy-RD, psy-trellis).
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The FFmpeg wrapper provides a mapping for most of them using global options
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that match those of the encoders and provides private options for the unique
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encoder options. Additionally an expert override is provided to directly pass
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a list of key=value tuples as accepted by x264_param_parse.
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Many libx264 encoder options are mapped to FFmpeg global codec
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options, while unique encoder options are provided through private
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options. Additionally the @option{x264opts} and @option{x264-params}
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private options allows to pass a list of key=value tuples as accepted
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by the libx264 @code{x264_param_parse} function.
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@subsection Option Mapping
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The x264 project website is at
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@url{http://www.videolan.org/developers/x264.html}.
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The following options are supported by the x264 wrapper, the x264-equivalent
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options follow the FFmpeg ones.
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@subsection Options
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@multitable @columnfractions .2 .2
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@item b @tab bitrate
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FFmpeg @code{b} option is expressed in bits/s, x264 @code{bitrate} in kilobits/s.
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@item bf @tab bframes
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Maximum number of B-frames.
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@item g @tab keyint
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Maximum GOP size.
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@item qmin @tab qpmin
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@item qmax @tab qpmax
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@item qdiff @tab qpstep
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@item qblur @tab qblur
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@item qcomp @tab qcomp
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@item refs @tab ref
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@item sc_threshold @tab scenecut
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@item trellis @tab trellis
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@item nr @tab nr
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Noise reduction.
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@item me_range @tab merange
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@item me_method @tab me
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@item subq @tab subme
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@item b_strategy @tab b-adapt
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@item keyint_min @tab keyint-min
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@item coder @tab cabac
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Set coder to @code{ac} to use CABAC.
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@item cmp @tab chroma-me
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Set to @code{chroma} to use chroma motion estimation.
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@item threads @tab threads
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@item thread_type @tab sliced_threads
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Set to @code{slice} to use sliced threading instead of frame threading.
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@item flags -cgop @tab open-gop
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Set @code{-cgop} to use recovery points to close GOPs.
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@item rc_init_occupancy @tab vbv-init
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Initial buffer occupancy.
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@end multitable
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The following options are supported by the libx264 wrapper. The
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@command{x264}-equivalent options or values are listed in parentheses
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for easy migration.
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To reduce the duplication of documentation, only the private options
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and some others requiring special attention are documented here. For
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the documentation of the undocumented generic options, see
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@ref{codec-options}.
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To get a more accurate and extensive documentation of the libx264
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options, invoke the command @command{x264 --full-help} or consult
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the libx264 documentation.
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@subsection Private Options
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@table @option
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@item -preset @var{string}
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Set the encoding preset (cf. x264 --fullhelp).
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@item -tune @var{string}
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Tune the encoding params (cf. x264 --fullhelp).
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@item -profile @var{string}
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Set profile restrictions (cf. x264 --fullhelp).
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@item -fastfirstpass @var{integer}
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Use fast settings when encoding first pass.
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@item -crf @var{float}
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Select the quality for constant quality mode.
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@item -crf_max @var{float}
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In CRF mode, prevents VBV from lowering quality beyond this point.
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@item -qp @var{integer}
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Constant quantization parameter rate control method.
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@item -aq-mode @var{integer}
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AQ method
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@item b (@emph{bitrate})
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Set bitrate in bits/s. Note that FFmpeg's @option{b} option is
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expressed in bits/s, while @command{x264}'s @option{bitrate} is in
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kilobits/s.
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@item bf (@emph{bframes})
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@item g (@emph{keyint})
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@item qmax (@emph{qpmax})
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@item qmin (@emph{qpmin})
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@item qdiff (@emph{qpstep})
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@item qblur (@emph{qblur})
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@item qcomp (@emph{qcomp})
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@item refs (@emph{ref})
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@item sc_threshold (@emph{scenecut})
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@item trellis (@emph{trellis})
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@item nr (@emph{nr})
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@item me_range (@emph{merange})
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@item me_method (@emph{me})
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Set motion estimation method. Possible values in the decreasing order
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of speed:
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Possible values:
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@table @samp
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@item none
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@item dia (@emph{dia})
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@item epzs (@emph{dia})
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Diamond search with radius 1 (fastest). @samp{epzs} is an alias for
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@samp{dia}.
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@item hex (@emph{hex})
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Hexagonal search with radius 2.
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@item umh (@emph{umh})
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Uneven multi-hexagon search.
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@item esa (@emph{esa})
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Exhaustive search.
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@item tesa (@emph{tesa})
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Hadamard exhaustive search (slowest).
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@end table
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@item variance
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@item subq (@emph{subme})
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@item b_strategy (@emph{b-adapt})
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@item keyint_min (@emph{min-keyint})
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@item coder
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Set entropy encoder. Possible values:
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@table @samp
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@item ac
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Enable CABAC.
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@item vlc
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Enable CAVLC and disable CABAC. It generates the same effect as
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@command{x264}'s @option{--no-cabac} option.
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@end table
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@item cmp
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Set full pixel motion estimation comparation algorithm. Possible values:
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@table @samp
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@item chroma
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Enable chroma in motion estimation.
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@item sad
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Ignore chroma in motion estimation. It generates the same effect as
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@command{x264}'s @option{--no-chroma-me} option.
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@end table
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@item threads (@emph{threads})
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@item thread_type
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Set multithreading technique. Possible values:
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@table @samp
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@item slice
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Slice-based multithreading. It generates the same effect as
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@command{x264}'s @option{--sliced-threads} option.
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@item frame
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Frame-based multithreading.
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@end table
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@item flags
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Set encoding flags. It can be used to disable closed GOP and enable
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open GOP by setting it to @code{-cgop}. The result is similar to
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the behavior of @command{x264}'s @option{--open-gop} option.
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@item rc_init_occupancy (@emph{vbv-init})
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@item preset (@emph{preset})
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Set the encoding preset.
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@item tune (@emph{tune})
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Set tuning of the encoding params.
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@item profile (@emph{profile})
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Set profile restrictions.
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@item fastfirstpass
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Enable fast settings when encoding first pass, when set to 1. When set
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to 0, it has the same effect of @command{x264}'s
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@option{--slow-firstpass} option.
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@item crf (@emph{crf})
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Set the quality for constant quality mode.
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@item crf_max (@emph{crf-max})
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In CRF mode, prevents VBV from lowering quality beyond this point.
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@item qp (@emph{qp})
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Set constant quantization rate control method parameter.
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@item aq-mode (@emph{aq-mode})
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Set AQ method. Possible values:
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@table @samp
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@item none (@emph{0})
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Disabled.
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@item variance (@emph{1})
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Variance AQ (complexity mask).
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@item autovariance
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@item autovariance (@emph{2})
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Auto-variance AQ (experimental).
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@end table
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@item -aq-strength @var{float}
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AQ strength, reduces blocking and blurring in flat and textured areas.
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@item -psy @var{integer}
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Use psychovisual optimizations.
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@item -psy-rd @var{string}
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Strength of psychovisual optimization, in <psy-rd>:<psy-trellis> format.
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@item -rc-lookahead @var{integer}
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Number of frames to look ahead for frametype and ratecontrol.
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@item -weightb @var{integer}
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Weighted prediction for B-frames.
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@item -weightp @var{integer}
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Weighted prediction analysis method.
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Possible values:
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@item aq-strength (@emph{aq-strength})
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Set AQ strength, reduce blocking and blurring in flat and textured areas.
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@item psy
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Use psychovisual optimizations when set to 1. When set to 0, it has the
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same effect as @command{x264}'s @option{--no-psy} option.
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@item psy-rd (@emph{psy-rd})
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Set strength of psychovisual optimization, in
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@var{psy-rd}:@var{psy-trellis} format.
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@item rc-lookahead (@emph{rc-lookahead})
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Set number of frames to look ahead for frametype and ratecontrol.
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@item weightb
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Enable weighted prediction for B-frames when set to 1. When set to 0,
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it has the same effect as @command{x264}'s @option{--no-weightb} option.
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@item weightp (@emph{weightp})
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Set weighted prediction method for P-frames. Possible values:
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@table @samp
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@item none
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@item simple
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@item smart
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@item none (@emph{0})
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Disabled
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@item simple (@emph{1})
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Enable only weighted refs
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@item smart (@emph{2})
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Enable both weighted refs and duplicates
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@end table
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@item -ssim @var{integer}
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Calculate and print SSIM stats.
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@item -intra-refresh @var{integer}
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Use Periodic Intra Refresh instead of IDR frames.
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@item -b-bias @var{integer}
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Influences how often B-frames are used.
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@item -b-pyramid @var{integer}
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Keep some B-frames as references.
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Possible values:
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@item ssim (@emph{ssim})
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Enable calculation and printing SSIM stats after the encoding.
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@item intra-refresh (@emph{intra-refresh})
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Enable the use of Periodic Intra Refresh instead of IDR frames when set
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to 1.
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@item b-bias (@emph{b-bias})
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Set the influence on how often B-frames are used.
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@item b-pyramid (@emph{b-pyramid})
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Set method for keeping of some B-frames as references. Possible values:
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@table @samp
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@item none
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@item strict
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@item none (@emph{none})
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Disabled.
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@item strict (@emph{strict})
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Strictly hierarchical pyramid.
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@item normal
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@item normal (@emph{normal})
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Non-strict (not Blu-ray compatible).
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@end table
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@item -mixed-refs @var{integer}
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One reference per partition, as opposed to one reference per macroblock.
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@item -8x8dct @var{integer}
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High profile 8x8 transform.
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@item -fast-pskip @var{integer}
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@item -aud @var{integer}
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Use access unit delimiters.
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@item -mbtree @var{integer}
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Use macroblock tree ratecontrol.
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@item -deblock @var{string}
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Loop filter parameters, in <alpha:beta> form.
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@item -cplxblur @var{float}
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Reduce fluctuations in QP (before curve compression).
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@item -partitions @var{string}
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A comma-separated list of partitions to consider, possible values: p8x8, p4x4, b8x8, i8x8, i4x4, none, all.
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@item -direct-pred @var{integer}
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Direct MV prediction mode
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Possible values:
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@item mixed-refs
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Enable the use of one reference per partition, as opposed to one
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reference per macroblock when set to 1. When set to 0, it has the
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same effect as @command{x264}'s @option{--no-mixed-refs} option.
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@item 8x8dct
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Enable adaptive spatial transform (high profile 8x8 transform)
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when set to 1. When set to 0, it has the same effect as
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@command{x264}'s @option{--no-8x8dct} option.
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@item fast-pskip
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Enable early SKIP detection on P-frames when set to 1. When set
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to 0, it has the same effect as @command{x264}'s
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@option{--no-fast-pskip} option.
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@item aud (@emph{aud})
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Enable use of access unit delimiters when set to 1.
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@item mbtree
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Enable use macroblock tree ratecontrol when set to 1. When set
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to 0, it has the same effect as @command{x264}'s
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@option{--no-mbtree} option.
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@item deblock (@emph{deblock})
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Set loop filter parameters, in @var{alpha}:@var{beta} form.
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@item cplxblur (@emph{cplxblur})
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Set fluctuations reduction in QP (before curve compression).
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@item partitions (@emph{partitions})
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Set partitions to consider as a comma-separated list of. Possible
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values in the list:
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@table @samp
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@item none
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@item spatial
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@item temporal
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@item auto
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@end table
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@item -slice-max-size @var{integer}
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Limit the size of each slice in bytes.
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@item -stats @var{string}
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Filename for 2 pass stats.
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@item -nal-hrd @var{integer}
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Signal HRD information (requires vbv-bufsize; cbr not allowed in .mp4).
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Possible values:
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@table @samp
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@item none
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@item vbr
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@item cbr
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@item p8x8
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8x8 P-frame partition.
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@item p4x4
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4x4 P-frame partition.
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@item b8x8
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4x4 B-frame partition.
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@item i8x8
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8x8 I-frame partition.
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@item i4x4
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4x4 I-frame partition.
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(Enabling @samp{p4x4} requires @samp{p8x8} to be enabled. Enabling
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@samp{i8x8} requires adaptive spatial transform (@option{8x8dct}
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option) to be enabled.)
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@item none (@emph{none})
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Do not consider any partitions.
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@item all (@emph{all})
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Consider every partition.
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@end table
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@item x264opts @var{options}
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Allow to set any x264 option, see @code{x264 --fullhelp} for a list.
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@item direct-pred (@emph{direct})
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Set direct MV prediction mode. Possible values:
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@var{options} is a list of @var{key}=@var{value} couples separated by
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@table @samp
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@item none (@emph{none})
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Disable MV prediction.
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@item spatial (@emph{spatial})
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Enable spatial predicting.
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@item temporal (@emph{temporal})
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Enable temporal predicting.
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@item auto (@emph{auto})
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Automatically decided.
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@end table
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@item slice-max-size (@emph{slice-max-size})
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Set the limit of the size of each slice in bytes. If not specified
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but RTP payload size (@option{ps}) is specified, that is used.
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@item stats (@emph{stats})
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Set the file name for multi-pass stats.
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@item nal-hrd (@emph{nal-hrd})
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Set signal HRD information (requires @option{vbv-bufsize} to be set).
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Possible values:
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@table @samp
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@item none (@emph{none})
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Disable HRD information signaling.
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@item vbr (@emph{vbr})
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Variable bit rate.
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@item cbr (@emph{cbr})
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Constant bit rate (not allowed in MP4 container).
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@end table
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@item x264opts (N.A.)
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Set any x264 option, see @command{x264 --fullhelp} for a list.
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Argument is a list of @var{key}=@var{value} couples separated by
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":". In @var{filter} and @var{psy-rd} options that use ":" as a separator
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themselves, use "," instead. They accept it as well since long ago but this
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is kept undocumented for some reason.
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|
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@ -1054,18 +1194,23 @@ For example to specify libx264 encoding options with @command{ffmpeg}:
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ffmpeg -i foo.mpg -vcodec libx264 -x264opts keyint=123:min-keyint=20 -an out.mkv
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@end example
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For more information about libx264 and the supported options see:
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@url{http://www.videolan.org/developers/x264.html}
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@item x264-params (N.A.)
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Override the x264 configuration using a :-separated list of key=value
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parameters.
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@item -x264-params @var{string}
|
||||
Override the x264 configuration using a :-separated list of key=value parameters.
|
||||
This option is functionally the same as the @option{x264opts}, but is
|
||||
duplicated for compability with the Libav fork.
|
||||
|
||||
For example to specify libx264 encoding options with @command{ffmpeg}:
|
||||
@example
|
||||
-x264-params level=30:bframes=0:weightp=0:cabac=0:ref=1:vbv-maxrate=768:vbv-bufsize=2000:analyse=all:me=umh:no-fast-pskip=1:subq=6:8x8dct=0:trellis=0
|
||||
ffmpeg -i INPUT -c:v libx264 -x264-params level=30:bframes=0:weightp=0:\
|
||||
cabac=0:ref=1:vbv-maxrate=768:vbv-bufsize=2000:analyse=all:me=umh:\
|
||||
no-fast-pskip=1:subq=6:8x8dct=0:trellis=0 OUTPUT
|
||||
@end example
|
||||
@end table
|
||||
|
||||
Encoding avpresets for common usages are provided so they can be used with the
|
||||
general presets system (e.g. passing the @code{-pre} option).
|
||||
Encoding ffpresets for common usages are provided so they can be used with the
|
||||
general presets system (e.g. passing the @option{pre} option).
|
||||
|
||||
@section png
|
||||
|
||||
|
|
|
|||
Loading…
Reference in New Issue