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  doc/encoders: document the QSV option mappings

Merged-by: Hendrik Leppkes <h.leppkes@gmail.com>
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Hendrik Leppkes 2015-11-29 15:24:29 +01:00
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doc/encoders.texi
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@ -2407,6 +2407,94 @@ by commas (,). See kvazaar documentation for a list of options.
@end table
@section QSV encoders
The family of Intel QuickSync Video encoders (MPEG-2, H.264 and HEVC)
The ratecontrol method is selected as follows:
@itemize @bullet
@item
When @option{global_quality} is specified, a quality-based mode is used.
Specifically this means either
@itemize @minus
@item
@var{CQP} - constant quantizer scale, when the @option{qscale} codec flag is
also set (the @option{-qscale} avconv option).
@item
@var{LA_ICQ} - intelligent constant quality with lookahead, when the
@option{look_ahead} option is also set.
@item
@var{ICQ} -- intelligent constant quality otherwise.
@end itemize
@item
Otherwise, a bitrate-based mode is used. For all of those, you should specify at
least the desired average bitrate with the @option{b} option.
@itemize @minus
@item
@var{LA} - VBR with lookahead, when the @option{look_ahead} option is specified.
@item
@var{VCM} - video conferencing mode, when the @option{vcm} option is set.
@item
@var{CBR} - constant bitrate, when @option{maxrate} is specified and equal to
the average bitrate.
@item
@var{VBR} - variable bitrate, when @option{maxrate} is specified, but is higher
than the average bitrate.
@item
@var{AVBR} - average VBR mode, when @option{maxrate} is not specified. This mode
is further configured by the @option{avbr_accuracy} and
@option{avbr_convergence} options.
@end itemize
@end itemize
Note that depending on your system, a different mode than the one you specified
may be selected by the encoder. Set the verbosity level to @var{verbose} or
higher to see the actual settings used by the QSV runtime.
Additional libavcodec global options are mapped to MSDK options as follows:
@itemize
@item
@option{g/gop_size} -> @option{GopPicSize}
@item
@option{bf/max_b_frames}+1 -> @option{GopRefDist}
@item
@option{rc_init_occupancy/rc_initial_buffer_occupancy} ->
@option{InitialDelayInKB}
@item
@option{slices} -> @option{NumSlice}
@item
@option{refs} -> @option{NumRefFrame}
@item
@option{b_strategy/b_frame_strategy} -> @option{BRefType}
@item
@option{cgop/CLOSED_GOP} codec flag -> @option{GopOptFlag}
@item
For the @var{CQP} mode, the @option{i_qfactor/i_qoffset} and
@option{b_qfactor/b_qoffset} set the difference between @var{QPP} and @var{QPI},
and @var{QPP} and @var{QPB} respectively.
@item
Setting the @option{coder} option to the value @var{vlc} will make the H.264
encoder use CAVLC instead of CABAC.
@end itemize
@c man end VIDEO ENCODERS
@chapter Subtitles Encoders