From e047cc0931a22d277d7ccd14588f905d7852f7e0 Mon Sep 17 00:00:00 2001 From: Niklas Haas Date: Mon, 16 May 2016 02:44:30 +0200 Subject: vo_opengl: implement more HDR tonemapping algorithms This is now a configurable option, with tunable parameters. I got inspiration for these algorithms off wikipedia. "simple" seems to work pretty well, but not well enough to make it a reasonable default. Some other notable candidates: - Local functions (e.g. based on local contrast or gradient) - Clamp with soft knee (linear up to a point) - Mapping in CIE L*Ch. Map L smoothly, clamp C and h. - Color appearance models These will have to be implemented some other time. Note that the parameter "peak_src" to pass_tone_map should, in principle, be auto-detected from the SEI information of the source file where available. This will also have to be implemented in a later commit. --- DOCS/man/vo.rst | 35 ++++++++++++++++++++++++++++++++--- 1 file changed, 32 insertions(+), 3 deletions(-) (limited to 'DOCS/man') diff --git a/DOCS/man/vo.rst b/DOCS/man/vo.rst index 046fa7e0e6..7792831dd5 100644 --- a/DOCS/man/vo.rst +++ b/DOCS/man/vo.rst @@ -1057,9 +1057,38 @@ Available video output drivers are: ``target-brightness=<1..100000>`` Specifies the display's approximate brightness in cd/m^2. When playing - HDR content, video colors will be scaled and clipped to this - brightness. The default of 250 cd/m^2 corresponds to a typical consumer - display. + HDR content, video colors will be tone mapped to this target brightness + using the algorithm specified by ``hdr-tone-mapping``. The default of + 250 cd/m^2 corresponds to a typical consumer display. + + ``hdr-tone-mapping=`` + Specifies the algorithm used for tone-mapping HDR images onto the + target display. Valid values are: + + clip + Hard-clip any out-of-range values (default) + simple + Very simple continuous curve. Preserves dynamic range and peak but + uses nonlinear contrast. + gamma + Fits a logarithmic transfer between the tone curves. + linear + Linearly stretches the entire reference gamut to (a linear multiple + of) the display. + + ``tone-mapping-param=`` + Set tone mapping parameters. Ignored if the tone mapping algorithm is + not tunable. This affects the following tone mapping algorithms: + + simple + Specifies the local contrast coefficient at the display peak. + Defaults to 0.5, which means that in-gamut values will be about + half as bright as when clipping. + gamma + Specifies the exponent of the function. Defaults to 1.8. + linear + Specifies the scale factor to use while stretching. Defaults to + 1.0. ``icc-profile=`` Load an ICC profile and use it to transform video RGB to screen output. -- cgit v1.2.3