diff options
Diffstat (limited to 'video/out/gl_video_shaders.glsl')
| -rw-r--r-- | video/out/gl_video_shaders.glsl | 54 |
1 files changed, 25 insertions, 29 deletions
diff --git a/video/out/gl_video_shaders.glsl b/video/out/gl_video_shaders.glsl index dac19cb673..3fd3f9ab75 100644 --- a/video/out/gl_video_shaders.glsl +++ b/video/out/gl_video_shaders.glsl @@ -110,11 +110,8 @@ void main() { // Although we are not scaling in linear light, both 3DLUT and SRGB still // operate on linear light inputs so we have to convert to it before // either step can be applied. -#ifdef USE_OSD_LINEAR_CONV_APPROX - color.rgb = pow(color.rgb, vec3(1.95)); -#endif -#ifdef USE_OSD_LINEAR_CONV_BT2020 - color.rgb = bt2020_expand(color.rgb); +#ifdef USE_OSD_LINEAR_CONV_BT1886 + color.rgb = pow(color.rgb, vec3(1.961)); #endif #ifdef USE_OSD_LINEAR_CONV_SRGB color.rgb = srgb_expand(color.rgb); @@ -416,6 +413,17 @@ void main() { // contributions from the three different channels. color.br = color.br * mix(vec2(1.5816, 0.9936), vec2(1.9404, 1.7184), lessThanEqual(color.br, vec2(0))) + color.gg; + + // Expand channels to camera-linear light. This shader currently just + // assumes everything uses the BT.2020 12-bit gamma function, since the + // difference between 10 and 12-bit is negligible for anything other than + // 12-bit content. + color = bt2020_expand(color); + // Calculate the green channel from the expanded RYcB + // The BT.2020 specification says Yc = 0.2627*R + 0.6780*G + 0.0593*B + color.g = (color.g - 0.2627*color.r - 0.0593*color.b)/0.6780; + // Re-compand to receive the R'G'B' result, same as other systems + color = bt2020_compand(color); #endif #ifdef USE_COLORMATRIX // CONST_LUMA involves numbers outside the [0,1] range so we make sure @@ -424,19 +432,18 @@ void main() { color = clamp(color, 0.0, 1.0); #endif // If we are scaling in linear light (SRGB or 3DLUT option enabled), we - // expand our source colors before scaling. This shader currently just - // assumes everything uses the BT.2020 12-bit gamma function, since the - // difference between this and BT.601, BT.709 and BT.2020 10-bit is well - // below the rounding error threshold for both 8-bit and even 10-bit - // content. It only makes a difference for 12-bit sources, so it should be - // fine to use here. -#ifdef USE_LINEAR_LIGHT_APPROX - // We differentiate between approximate BT.2020 (gamma 1.95) ... - color = pow(color, vec3(1.95)); -#endif -#ifdef USE_LINEAR_LIGHT_BT2020 - // ... and actual BT.2020 (two-part function) - color = bt2020_expand(color); + // expand our source colors before scaling. We distinguish between + // BT.1886 (typical video files) and sRGB (typical image files). +#ifdef USE_LINEAR_LIGHT_BT1886 + // This calculation is derived from the BT.1886 recommendation which + // is itself derived from the curves of typical CRT monitors. It claims + // that a correct video playback environment should have a pure power + // curve transfer function (in contrast to the complex BT.709 function) + // with a gamma value of 2.40, but this includes the typical gamma boost + // of ~1.2 for dark viewing environments. The figure used here instead + // (1.961) is therefore a pure power curve but without the boost, which + // is a very close approximation of the true BT.709 function. + color = pow(color, vec3(1.961)); #endif #ifdef USE_LINEAR_LIGHT_SRGB // This is not needed for most sRGB content since we can use GL_SRGB to @@ -445,11 +452,6 @@ void main() { // to convert to linear light manually. color = srgb_expand(color); #endif -#ifdef USE_CONST_LUMA - // Calculate the green channel from the expanded RYcB - // The BT.2020 specification says Yc = 0.2627*R + 0.6780*G + 0.0593*B - color.g = (color.g - 0.2627*color.r - 0.0593*color.b)/0.6780; -#endif #ifdef USE_SIGMOID color = sig_center - log(1.0/(color * sig_scale + sig_offset) - 1.0)/sig_slope; #endif @@ -485,12 +487,6 @@ void main() { // Adapt and compand from the linear BT2020 source to the sRGB output color = srgb_compand(color); #endif - // If none of these options took care of companding again (ie. CMS is - // disabled), we still need to re-compand const luma signals, because - // they always come out as linear light (and we can't simply output that). -#ifdef USE_CONST_LUMA_INV - color = bt2020_compand(color); -#endif #ifdef USE_DITHER vec2 dither_pos = gl_FragCoord.xy / dither_size; #ifdef USE_TEMPORAL_DITHER |