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