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Updated default SDR white point and HDR headroom to better match game content

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This commit is contained in:
Sam Lantinga
2024-02-22 14:51:23 -08:00
parent 1fb5b9672e
commit 2f1f55aeb1
1 changed files with 8 additions and 2 deletions
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10
src/video/SDL_surface.c
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@@ -323,7 +323,12 @@ float SDL_GetSurfaceSDRWhitePoint(SDL_Surface *surface, SDL_Colorspace colorspac
props = 0; props = 0;
} }
if (transfer == SDL_TRANSFER_CHARACTERISTICS_PQ) { if (transfer == SDL_TRANSFER_CHARACTERISTICS_PQ) {
const float DEFAULT_PQ_SDR_WHITE_POINT = 100.0f; /* The older standards use an SDR white point of 100 nits.
* ITU-R BT.2408-6 recommends using an SDR white point of 203 nits.
* This is the default Chrome uses, and what a lot of game content
* assumes, so we'll go with that.
*/
const float DEFAULT_PQ_SDR_WHITE_POINT = 203.0f;
default_value = DEFAULT_PQ_SDR_WHITE_POINT; default_value = DEFAULT_PQ_SDR_WHITE_POINT;
} }
return SDL_GetFloatProperty(props, SDL_PROP_SURFACE_SDR_WHITE_POINT_FLOAT, default_value); return SDL_GetFloatProperty(props, SDL_PROP_SURFACE_SDR_WHITE_POINT_FLOAT, default_value);
@@ -351,7 +356,8 @@ float SDL_GetSurfaceHDRHeadroom(SDL_Surface *surface, SDL_Colorspace colorspace)
props = 0; props = 0;
} }
if (transfer == SDL_TRANSFER_CHARACTERISTICS_PQ) { if (transfer == SDL_TRANSFER_CHARACTERISTICS_PQ) {
const int DEFAULT_PQ_MAXCLL = 400; /* The official definition is 10000, but PQ game content is often mastered for 400 nits */ /* The official definition is 10000, but PQ game content is often mastered for 400 or 1000 nits */
const int DEFAULT_PQ_MAXCLL = 1000;
default_value = (float)SDL_GetNumberProperty(props, SDL_PROP_SURFACE_MAXCLL_NUMBER, DEFAULT_PQ_MAXCLL) / SDL_GetSurfaceSDRWhitePoint(surface, colorspace); default_value = (float)SDL_GetNumberProperty(props, SDL_PROP_SURFACE_MAXCLL_NUMBER, DEFAULT_PQ_MAXCLL) / SDL_GetSurfaceSDRWhitePoint(surface, colorspace);
} }
return SDL_GetFloatProperty(props, SDL_PROP_SURFACE_HDR_HEADROOM_FLOAT, default_value); return SDL_GetFloatProperty(props, SDL_PROP_SURFACE_HDR_HEADROOM_FLOAT, default_value);