diff options
Diffstat (limited to 'video/out/opengl/video_shaders.c')
-rw-r--r-- | video/out/opengl/video_shaders.c | 90 |
1 files changed, 82 insertions, 8 deletions
diff --git a/video/out/opengl/video_shaders.c b/video/out/opengl/video_shaders.c index 14120d434b..f56c687903 100644 --- a/video/out/opengl/video_shaders.c +++ b/video/out/opengl/video_shaders.c @@ -368,6 +368,81 @@ void pass_delinearize(struct gl_shader_cache *sc, enum mp_csp_trc trc) } } +// Apply the OOTF mapping from a given light type to display-referred light. +// The extra peak parameter is used to scale the values before and after +// the OOTF, and can be inferred using mp_trc_nom_peak +void pass_ootf(struct gl_shader_cache *sc, enum mp_csp_light light, float peak) +{ + if (light == MP_CSP_LIGHT_DISPLAY) + return; + + GLSLF("// apply ootf\n", sc); + GLSLF("color.rgb *= vec3(%f);\n", peak); + + switch (light) + { + case MP_CSP_LIGHT_SCENE_HLG: + // HLG OOTF from BT.2100, assuming a reference display with a + // peak of 1000 cd/m² -> gamma = 1.2 + GLSL(float luma = dot(color.rgb, vec3(0.2627, 0.6780, 0.0593));) + GLSLF("color.rgb *= vec3(%f * pow(luma, 0.2));\n", + (1000 / MP_REF_WHITE) / pow(12, 1.2)); + break; + case MP_CSP_LIGHT_SCENE_709_1886: + // This OOTF is defined by encoding the result as 709 and then decoding + // it as 1886; although this is called 709_1886 we actually use the + // more precise (by one decimal) values from BT.2020 instead + GLSL(color.rgb = mix(color.rgb * vec3(4.5), + vec3(1.0993) * pow(color.rgb, vec3(0.45)) - vec3(0.0993), + lessThan(vec3(0.0181), color.rgb));) + GLSL(color.rgb = pow(color.rgb, vec3(2.4));) + break; + case MP_CSP_LIGHT_SCENE_1_2: + GLSL(color.rgb = pow(color.rgb, vec3(1.2));) + break; + default: + abort(); + } + + GLSLF("color.rgb /= vec3(%f);\n", peak); +} + +// Inverse of the function pass_ootf, for completeness' sake. Note that the +// inverse OOTF for MP_CSP_LIGHT_SCENE_HLG has no analytical solution and is +// therefore unimplemented. Care must be used to never call this function +// in that way.(In principle, a iterative algorithm can approach +// the solution numerically, but this is tricky and we don't really need it +// since mpv currently only supports outputting display-referred light) +void pass_inverse_ootf(struct gl_shader_cache *sc, enum mp_csp_light light, float peak) +{ + if (light == MP_CSP_LIGHT_DISPLAY) + return; + + GLSLF("// apply inverse ootf\n"); + GLSLF("color.rgb *= vec3(%f);\n", peak); + + switch (light) + { + case MP_CSP_LIGHT_SCENE_HLG: + // Has no analytical solution + abort(); + break; + case MP_CSP_LIGHT_SCENE_709_1886: + GLSL(color.rgb = pow(color.rgb, vec3(1/2.4));) + GLSL(color.rgb = mix(color.rgb / vec3(4.5), + pow((color.rgb + vec3(0.0993)) / vec3(1.0993), vec3(1/0.45)), + lessThan(vec3(0.08145), color.rgb));) + break; + case MP_CSP_LIGHT_SCENE_1_2: + GLSL(color.rgb = pow(color.rgb, vec3(1/1.2));) + break; + default: + abort(); + } + + GLSLF("color.rgb /= vec3(%f);\n", peak); +} + // Tone map from a known peak brightness to the range [0,1] static void pass_tone_map(struct gl_shader_cache *sc, float ref_peak, enum tone_mapping algo, float param) @@ -452,20 +527,16 @@ void pass_color_map(struct gl_shader_cache *sc, bool need_gamma = src.gamma != dst.gamma || src.primaries != dst.primaries || src_range != dst_range || - src.sig_peak > dst_range; + src.sig_peak > dst_range || + src.light != dst.light; if (need_gamma && !is_linear) { pass_linearize(sc, src.gamma); is_linear= true; } - // NOTE: When src.gamma = MP_CSP_TRC_ARIB_STD_B67, we would technically - // need to apply the reference OOTF as part of the EOTF (which is what we - // implement with pass_linearize), since HLG considers OOTF to be part of - // the display's EOTF (as opposed to the camera's OETF) - although arguably - // in our case this would be part of the ICC profile, not mpv. Either way, - // in case somebody ends up complaining about HLG looking different from a - // reference HLG display, this comment might be why. + if (src.light != dst.light) + pass_ootf(sc, src.light, mp_trc_nom_peak(src.gamma)); // Rescale the signal to compensate for differences in the encoding range // and reference white level. This is necessary because of how mpv encodes @@ -490,6 +561,9 @@ void pass_color_map(struct gl_shader_cache *sc, GLSL(color.rgb = cms_matrix * color.rgb;) } + if (src.light != dst.light) + pass_inverse_ootf(sc, dst.light, mp_trc_nom_peak(dst.gamma)); + if (is_linear) pass_delinearize(sc, dst.gamma); } |