Signed-off-by: Ruiling Song <ruiling.s...@intel.com> --- doc/filters.texi | 158 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 158 insertions(+)
diff --git a/doc/filters.texi b/doc/filters.texi index 6695999c84..f622d03226 100644 --- a/doc/filters.texi +++ b/doc/filters.texi @@ -17776,6 +17776,164 @@ 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. + +Possible values are: +@table @var +@item none +Do not apply any tone mapping, only desaturate overbright pixels. + +@item clip +Hard-clip any out-of-range values. Use it for perfect color accuracy for +in-range values, while distorting out-of-range values. + +@item linear +Stretch the entire reference gamut to a linear multiple of the display. + +@item gamma +Fit a logarithmic transfer between the tone curves. + +@item reinhard +Preserve overall image brightness with a simple curve, using nonlinear +contrast, which results in flattening details and degrading color accuracy. + +@item hable +Preserve both dark and bright details better than @var{reinhard}, at the cost +of slightly darkening everything. Use it when detail preservation is more +important than color and brightness accuracy. + +@item mobius +Smoothly map out-of-range values, while retaining contrast and colors for +in-range material as much as possible. Use it when color accuracy is more +important than detail preservation. +@end table + +@item param +Tune the tone mapping algorithm. + +This affects the following algorithms: +@table @var +@item none +Ignored. + +@item linear +Specifies the scale factor to use while stretching. +Default to 1.0. + +@item gamma +Specifies the exponent of the function. +Default to 1.8. + +@item clip +Specify an extra linear coefficient to multiply into the signal before clipping. +Default to 1.0. + +@item reinhard +Specify the local contrast coefficient at the display peak. +Default to 0.5, which means that in-gamut values will be about half as bright +as when clipping. + +@item hable +Ignored. + +@item mobius +Specify the transition point from linear to mobius transform. Every value +below this point is guaranteed to be mapped 1:1. The higher the value, the +more accurate the result will be, at the cost of losing bright details. +Default to 0.3, which due to the steep initial slope still preserves in-range +colors fairly accurately. +@end table + +@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 "hwupload, format=p010,tonemap_opencl=t=bt2020:tonemap=linear:format=p010, hwdownload" OUTPUT +@end example +@end itemize + @section unsharp_opencl Sharpen or blur the input video. -- 2.17.0 _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel