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doc/filters: add tonemap_opencl document.

Signed-off-by: Ruiling Song <ruiling.song@intel.com>
Signed-off-by: Gyan Doshi <gyandoshi@gmail.com>
This commit is contained in:
Ruiling Song 2018-10-29 13:56:59 +08:00 committed by Lou Logan
parent 952a299fd3
commit a587454fd0

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@ -16650,6 +16650,7 @@ tmix=frames=3:weights="-1 2 -1":scale=1
@end example
@end itemize
@anchor{tonemap}
@section tonemap
Tone map colors from different dynamic ranges.
@ -18885,6 +18886,101 @@ Apply sobel operator with scale set to 2 and delta set to 10
@end example
@end itemize
@section tonemap_opencl
Perform HDR(PQ/HLG) to SDR conversion with tone-mapping.
It accepts the following parameters:
@table @option
@item tonemap
Specify the tone-mapping operator to be used. Same as tonemap option in @ref{tonemap}.
@item param
Tune the tone mapping algorithm. same as param option in @ref{tonemap}.
@item desat
Apply desaturation for highlights that exceed this level of brightness. The
higher the parameter, the more color information will be preserved. This
setting helps prevent unnaturally blown-out colors for super-highlights, by
(smoothly) turning into white instead. This makes images feel more natural,
at the cost of reducing information about out-of-range colors.
The default value is 0.5, and the algorithm here is a little different from
the cpu version tonemap currently. A setting of 0.0 disables this option.
@item threshold
The tonemapping algorithm parameters is fine-tuned per each scene. And a threshold
is used to detect whether the scene has changed or not. If the distance beween
the current frame average brightness and the current running average exceeds
a threshold value, we would re-calculate scene average and peak brightness.
The default value is 0.2.
@item format
Specify the output pixel format.
Currently supported formats are:
@table @var
@item p010
@item nv12
@end table
@item range, r
Set the output color range.
Possible values are:
@table @var
@item tv/mpeg
@item pc/jpeg
@end table
Default is same as input.
@item primaries, p
Set the output color primaries.
Possible values are:
@table @var
@item bt709
@item bt2020
@end table
Default is same as input.
@item transfer, t
Set the output transfer characteristics.
Possible values are:
@table @var
@item bt709
@item bt2020
@end table
Default is bt709.
@item matrix, m
Set the output colorspace matrix.
Possible value are:
@table @var
@item bt709
@item bt2020
@end table
Default is same as input.
@end table
@subsection Example
@itemize
@item
Convert HDR(PQ/HLG) video to bt2020-transfer-characteristic p010 format using linear operator.
@example
-i INPUT -vf "format=p010,hwupload,tonemap_opencl=t=bt2020:tonemap=linear:format=p010,hwdownload,format=p010" OUTPUT
@end example
@end itemize
@section unsharp_opencl
Sharpen or blur the input video.