| /* |
| * This file is part of FFmpeg. |
| * |
| * FFmpeg is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU Lesser General Public |
| * License as published by the Free Software Foundation; either |
| * version 2.1 of the License, or (at your option) any later version. |
| * |
| * FFmpeg is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| * Lesser General Public License for more details. |
| * |
| * You should have received a copy of the GNU Lesser General Public |
| * License along with FFmpeg; if not, write to the Free Software |
| * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| */ |
| |
| #define ST2084_MAX_LUMINANCE 10000.0f |
| #define REFERENCE_WHITE 100.0f |
| |
| #if chroma_loc == 1 |
| #define chroma_sample(a,b,c,d) (((a) + (c)) * 0.5f) |
| #elif chroma_loc == 3 |
| #define chroma_sample(a,b,c,d) (a) |
| #elif chroma_loc == 4 |
| #define chroma_sample(a,b,c,d) (((a) + (b)) * 0.5f) |
| #elif chroma_loc == 5 |
| #define chroma_sample(a,b,c,d) (c) |
| #elif chroma_loc == 6 |
| #define chroma_sample(a,b,c,d) (((c) + (d)) * 0.5f) |
| #else |
| #define chroma_sample(a,b,c,d) (((a) + (b) + (c) + (d)) * 0.25f) |
| #endif |
| |
| constant const float ST2084_M1 = 0.1593017578125f; |
| constant const float ST2084_M2 = 78.84375f; |
| constant const float ST2084_C1 = 0.8359375f; |
| constant const float ST2084_C2 = 18.8515625f; |
| constant const float ST2084_C3 = 18.6875f; |
| |
| float get_luma_dst(float3 c) { |
| return luma_dst.x * c.x + luma_dst.y * c.y + luma_dst.z * c.z; |
| } |
| |
| float get_luma_src(float3 c) { |
| return luma_src.x * c.x + luma_src.y * c.y + luma_src.z * c.z; |
| } |
| |
| float3 get_chroma_sample(float3 a, float3 b, float3 c, float3 d) { |
| return chroma_sample(a, b, c, d); |
| } |
| |
| float eotf_st2084(float x) { |
| float p = powr(x, 1.0f / ST2084_M2); |
| float a = max(p -ST2084_C1, 0.0f); |
| float b = max(ST2084_C2 - ST2084_C3 * p, 1e-6f); |
| float c = powr(a / b, 1.0f / ST2084_M1); |
| return x > 0.0f ? c * ST2084_MAX_LUMINANCE / REFERENCE_WHITE : 0.0f; |
| } |
| |
| __constant const float HLG_A = 0.17883277f; |
| __constant const float HLG_B = 0.28466892f; |
| __constant const float HLG_C = 0.55991073f; |
| |
| // linearizer for HLG |
| float inverse_oetf_hlg(float x) { |
| float a = 4.0f * x * x; |
| float b = exp((x - HLG_C) / HLG_A) + HLG_B; |
| return x < 0.5f ? a : b; |
| } |
| |
| // delinearizer for HLG |
| float oetf_hlg(float x) { |
| float a = 0.5f * sqrt(x); |
| float b = HLG_A * log(x - HLG_B) + HLG_C; |
| return x <= 1.0f ? a : b; |
| } |
| |
| float3 ootf_hlg(float3 c, float peak) { |
| float luma = get_luma_src(c); |
| float gamma = 1.2f + 0.42f * log10(peak * REFERENCE_WHITE / 1000.0f); |
| gamma = max(1.0f, gamma); |
| float factor = peak * powr(luma, gamma - 1.0f) / powr(12.0f, gamma); |
| return c * factor; |
| } |
| |
| float3 inverse_ootf_hlg(float3 c, float peak) { |
| float gamma = 1.2f + 0.42f * log10(peak * REFERENCE_WHITE / 1000.0f); |
| c *= powr(12.0f, gamma) / peak; |
| c /= powr(get_luma_dst(c), (gamma - 1.0f) / gamma); |
| return c; |
| } |
| |
| float inverse_eotf_bt1886(float c) { |
| return c < 0.0f ? 0.0f : powr(c, 1.0f / 2.4f); |
| } |
| |
| float oetf_bt709(float c) { |
| c = c < 0.0f ? 0.0f : c; |
| float r1 = 4.5f * c; |
| float r2 = 1.099f * powr(c, 0.45f) - 0.099f; |
| return c < 0.018f ? r1 : r2; |
| } |
| float inverse_oetf_bt709(float c) { |
| float r1 = c / 4.5f; |
| float r2 = powr((c + 0.099f) / 1.099f, 1.0f / 0.45f); |
| return c < 0.081f ? r1 : r2; |
| } |
| |
| float3 yuv2rgb(float y, float u, float v) { |
| #ifdef FULL_RANGE_IN |
| u -= 0.5f; v -= 0.5f; |
| #else |
| y = (y * 255.0f - 16.0f) / 219.0f; |
| u = (u * 255.0f - 128.0f) / 224.0f; |
| v = (v * 255.0f - 128.0f) / 224.0f; |
| #endif |
| float r = y * rgb_matrix[0] + u * rgb_matrix[1] + v * rgb_matrix[2]; |
| float g = y * rgb_matrix[3] + u * rgb_matrix[4] + v * rgb_matrix[5]; |
| float b = y * rgb_matrix[6] + u * rgb_matrix[7] + v * rgb_matrix[8]; |
| return (float3)(r, g, b); |
| } |
| |
| float3 yuv2lrgb(float3 yuv) { |
| float3 rgb = yuv2rgb(yuv.x, yuv.y, yuv.z); |
| #ifdef linearize |
| float r = linearize(rgb.x); |
| float g = linearize(rgb.y); |
| float b = linearize(rgb.z); |
| return (float3)(r, g, b); |
| #else |
| return rgb; |
| #endif |
| } |
| |
| float3 rgb2yuv(float r, float g, float b) { |
| float y = r*yuv_matrix[0] + g*yuv_matrix[1] + b*yuv_matrix[2]; |
| float u = r*yuv_matrix[3] + g*yuv_matrix[4] + b*yuv_matrix[5]; |
| float v = r*yuv_matrix[6] + g*yuv_matrix[7] + b*yuv_matrix[8]; |
| #ifdef FULL_RANGE_OUT |
| u += 0.5f; v += 0.5f; |
| #else |
| y = (219.0f * y + 16.0f) / 255.0f; |
| u = (224.0f * u + 128.0f) / 255.0f; |
| v = (224.0f * v + 128.0f) / 255.0f; |
| #endif |
| return (float3)(y, u, v); |
| } |
| |
| float rgb2y(float r, float g, float b) { |
| float y = r*yuv_matrix[0] + g*yuv_matrix[1] + b*yuv_matrix[2]; |
| y = (219.0f * y + 16.0f) / 255.0f; |
| return y; |
| } |
| |
| float3 lrgb2yuv(float3 c) { |
| #ifdef delinearize |
| float r = delinearize(c.x); |
| float g = delinearize(c.y); |
| float b = delinearize(c.z); |
| return rgb2yuv(r, g, b); |
| #else |
| return rgb2yuv(c.x, c.y, c.z); |
| #endif |
| } |
| |
| float lrgb2y(float3 c) { |
| #ifdef delinearize |
| float r = delinearize(c.x); |
| float g = delinearize(c.y); |
| float b = delinearize(c.z); |
| return rgb2y(r, g, b); |
| #else |
| return rgb2y(c.x, c.y, c.z); |
| #endif |
| } |
| |
| float3 lrgb2lrgb(float3 c) { |
| #ifdef RGB2RGB_PASSTHROUGH |
| return c; |
| #else |
| float r = c.x, g = c.y, b = c.z; |
| float rr = rgb2rgb[0] * r + rgb2rgb[1] * g + rgb2rgb[2] * b; |
| float gg = rgb2rgb[3] * r + rgb2rgb[4] * g + rgb2rgb[5] * b; |
| float bb = rgb2rgb[6] * r + rgb2rgb[7] * g + rgb2rgb[8] * b; |
| return (float3)(rr, gg, bb); |
| #endif |
| } |
| |
| float3 ootf(float3 c, float peak) { |
| #ifdef ootf_impl |
| return ootf_impl(c, peak); |
| #else |
| return c; |
| #endif |
| } |
| |
| float3 inverse_ootf(float3 c, float peak) { |
| #ifdef inverse_ootf_impl |
| return inverse_ootf_impl(c, peak); |
| #else |
| return c; |
| #endif |
| } |