/* * Copyright (c) 2015 Kevin Wheatley * Copyright (c) 2016 Ronald S. Bultje * Copyright (c) 2023 Leo Izen * * 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 */ /** * @file Colorspace functions for libavutil * @author Ronald S. Bultje * @author Leo Izen * @author Kevin Wheatley */ #include #include #include "attributes.h" #include "csp.h" #include "pixfmt.h" #include "rational.h" #define AVR(d) { (int)(d * 100000 + 0.5), 100000 } /* * All constants explained in e.g. https://linuxtv.org/downloads/v4l-dvb-apis/ch02s06.html * The older ones (bt470bg/m) are also explained in their respective ITU docs * (e.g. https://www.itu.int/dms_pubrec/itu-r/rec/bt/R-REC-BT.470-5-199802-S!!PDF-E.pdf) * whereas the newer ones can typically be copied directly from wikipedia :) */ static const struct AVLumaCoefficients luma_coefficients[AVCOL_SPC_NB] = { [AVCOL_SPC_FCC] = { AVR(0.30), AVR(0.59), AVR(0.11) }, [AVCOL_SPC_BT470BG] = { AVR(0.299), AVR(0.587), AVR(0.114) }, [AVCOL_SPC_SMPTE170M] = { AVR(0.299), AVR(0.587), AVR(0.114) }, [AVCOL_SPC_BT709] = { AVR(0.2126), AVR(0.7152), AVR(0.0722) }, [AVCOL_SPC_SMPTE240M] = { AVR(0.212), AVR(0.701), AVR(0.087) }, [AVCOL_SPC_YCOCG] = { AVR(0.25), AVR(0.5), AVR(0.25) }, [AVCOL_SPC_RGB] = { AVR(1), AVR(1), AVR(1) }, [AVCOL_SPC_BT2020_NCL] = { AVR(0.2627), AVR(0.6780), AVR(0.0593) }, [AVCOL_SPC_BT2020_CL] = { AVR(0.2627), AVR(0.6780), AVR(0.0593) }, }; const struct AVLumaCoefficients *av_csp_luma_coeffs_from_avcsp(enum AVColorSpace csp) { const AVLumaCoefficients *coeffs; if (csp >= AVCOL_SPC_NB) return NULL; coeffs = &luma_coefficients[csp]; if (!coeffs->cr.num) return NULL; return coeffs; } #define WP_D65 { AVR(0.3127), AVR(0.3290) } #define WP_C { AVR(0.3100), AVR(0.3160) } #define WP_DCI { AVR(0.3140), AVR(0.3510) } #define WP_E { {1, 3}, {1, 3} } static const AVColorPrimariesDesc color_primaries[AVCOL_PRI_NB] = { [AVCOL_PRI_BT709] = { WP_D65, { { AVR(0.640), AVR(0.330) }, { AVR(0.300), AVR(0.600) }, { AVR(0.150), AVR(0.060) } } }, [AVCOL_PRI_BT470M] = { WP_C, { { AVR(0.670), AVR(0.330) }, { AVR(0.210), AVR(0.710) }, { AVR(0.140), AVR(0.080) } } }, [AVCOL_PRI_BT470BG] = { WP_D65, { { AVR(0.640), AVR(0.330) }, { AVR(0.290), AVR(0.600) }, { AVR(0.150), AVR(0.060) } } }, [AVCOL_PRI_SMPTE170M] = { WP_D65, { { AVR(0.630), AVR(0.340) }, { AVR(0.310), AVR(0.595) }, { AVR(0.155), AVR(0.070) } } }, [AVCOL_PRI_SMPTE240M] = { WP_D65, { { AVR(0.630), AVR(0.340) }, { AVR(0.310), AVR(0.595) }, { AVR(0.155), AVR(0.070) } } }, [AVCOL_PRI_SMPTE428] = { WP_E, { { AVR(0.735), AVR(0.265) }, { AVR(0.274), AVR(0.718) }, { AVR(0.167), AVR(0.009) } } }, [AVCOL_PRI_SMPTE431] = { WP_DCI, { { AVR(0.680), AVR(0.320) }, { AVR(0.265), AVR(0.690) }, { AVR(0.150), AVR(0.060) } } }, [AVCOL_PRI_SMPTE432] = { WP_D65, { { AVR(0.680), AVR(0.320) }, { AVR(0.265), AVR(0.690) }, { AVR(0.150), AVR(0.060) } } }, [AVCOL_PRI_FILM] = { WP_C, { { AVR(0.681), AVR(0.319) }, { AVR(0.243), AVR(0.692) }, { AVR(0.145), AVR(0.049) } } }, [AVCOL_PRI_BT2020] = { WP_D65, { { AVR(0.708), AVR(0.292) }, { AVR(0.170), AVR(0.797) }, { AVR(0.131), AVR(0.046) } } }, [AVCOL_PRI_JEDEC_P22] = { WP_D65, { { AVR(0.630), AVR(0.340) }, { AVR(0.295), AVR(0.605) }, { AVR(0.155), AVR(0.077) } } }, }; const AVColorPrimariesDesc *av_csp_primaries_desc_from_id(enum AVColorPrimaries prm) { const AVColorPrimariesDesc *p; if (prm >= AVCOL_PRI_NB) return NULL; p = &color_primaries[prm]; if (!p->prim.r.x.num) return NULL; return p; } static av_always_inline AVRational abs_sub_q(AVRational r1, AVRational r2) { AVRational diff = av_sub_q(r1, r2); /* denominator assumed to be positive */ return av_make_q(abs(diff.num), diff.den); } enum AVColorPrimaries av_csp_primaries_id_from_desc(const AVColorPrimariesDesc *prm) { AVRational delta; for (enum AVColorPrimaries p = 0; p < AVCOL_PRI_NB; p++) { const AVColorPrimariesDesc *ref = &color_primaries[p]; if (!ref->prim.r.x.num) continue; delta = abs_sub_q(prm->prim.r.x, ref->prim.r.x); delta = av_add_q(delta, abs_sub_q(prm->prim.r.y, ref->prim.r.y)); delta = av_add_q(delta, abs_sub_q(prm->prim.g.x, ref->prim.g.x)); delta = av_add_q(delta, abs_sub_q(prm->prim.g.y, ref->prim.g.y)); delta = av_add_q(delta, abs_sub_q(prm->prim.b.x, ref->prim.b.x)); delta = av_add_q(delta, abs_sub_q(prm->prim.b.y, ref->prim.b.y)); delta = av_add_q(delta, abs_sub_q(prm->wp.x, ref->wp.x)); delta = av_add_q(delta, abs_sub_q(prm->wp.y, ref->wp.y)); if (av_cmp_q(delta, av_make_q(1, 1000)) < 0) return p; } return AVCOL_PRI_UNSPECIFIED; } static const double approximate_gamma[AVCOL_TRC_NB] = { [AVCOL_TRC_BT709] = 1.961, [AVCOL_TRC_SMPTE170M] = 1.961, [AVCOL_TRC_SMPTE240M] = 1.961, [AVCOL_TRC_BT1361_ECG] = 1.961, [AVCOL_TRC_BT2020_10] = 1.961, [AVCOL_TRC_BT2020_12] = 1.961, [AVCOL_TRC_GAMMA22] = 2.2, [AVCOL_TRC_IEC61966_2_1] = 2.2, [AVCOL_TRC_GAMMA28] = 2.8, [AVCOL_TRC_LINEAR] = 1.0, [AVCOL_TRC_SMPTE428] = 2.6, }; double av_csp_approximate_trc_gamma(enum AVColorTransferCharacteristic trc) { double gamma; if (trc >= AVCOL_TRC_NB) return 0.0; gamma = approximate_gamma[trc]; if (gamma > 0) return gamma; return 0.0; } #define BT709_alpha 1.099296826809442 #define BT709_beta 0.018053968510807 static double trc_bt709(double Lc) { const double a = BT709_alpha; const double b = BT709_beta; return (0.0 > Lc) ? 0.0 : ( b > Lc) ? 4.500 * Lc : a * pow(Lc, 0.45) - (a - 1.0); } static double trc_gamma22(double Lc) { return (0.0 > Lc) ? 0.0 : pow(Lc, 1.0/ 2.2); } static double trc_gamma28(double Lc) { return (0.0 > Lc) ? 0.0 : pow(Lc, 1.0/ 2.8); } static double trc_smpte240M(double Lc) { const double a = 1.1115; const double b = 0.0228; return (0.0 > Lc) ? 0.0 : ( b > Lc) ? 4.000 * Lc : a * pow(Lc, 0.45) - (a - 1.0); } static double trc_linear(double Lc) { return Lc; } static double trc_log(double Lc) { return (0.01 > Lc) ? 0.0 : 1.0 + log10(Lc) / 2.0; } static double trc_log_sqrt(double Lc) { // sqrt(10) / 1000 return (0.00316227766 > Lc) ? 0.0 : 1.0 + log10(Lc) / 2.5; } static double trc_iec61966_2_4(double Lc) { const double a = BT709_alpha; const double b = BT709_beta; return (-b >= Lc) ? -a * pow(-Lc, 0.45) + (a - 1.0) : ( b > Lc) ? 4.500 * Lc : a * pow( Lc, 0.45) - (a - 1.0); } static double trc_bt1361(double Lc) { const double a = BT709_alpha; const double b = BT709_beta; return (-0.0045 >= Lc) ? -(a * pow(-4.0 * Lc, 0.45) + (a - 1.0)) / 4.0 : ( b > Lc) ? 4.500 * Lc : a * pow( Lc, 0.45) - (a - 1.0); } static double trc_iec61966_2_1(double Lc) { const double a = 1.055; const double b = 0.0031308; return (0.0 > Lc) ? 0.0 : ( b > Lc) ? 12.92 * Lc : a * pow(Lc, 1.0 / 2.4) - (a - 1.0); } static double trc_smpte_st2084(double Lc) { const double c1 = 3424.0 / 4096.0; // c3-c2 + 1 const double c2 = 32.0 * 2413.0 / 4096.0; const double c3 = 32.0 * 2392.0 / 4096.0; const double m = 128.0 * 2523.0 / 4096.0; const double n = 0.25 * 2610.0 / 4096.0; const double L = Lc / 10000.0; const double Ln = pow(L, n); return (0.0 > Lc) ? 0.0 : pow((c1 + c2 * Ln) / (1.0 + c3 * Ln), m); } static double trc_smpte_st428_1(double Lc) { return (0.0 > Lc) ? 0.0 : pow(48.0 * Lc / 52.37, 1.0 / 2.6); } static double trc_arib_std_b67(double Lc) { // The function uses the definition from HEVC, which assumes that the peak // white is input level = 1. (this is equivalent to scaling E = Lc * 12 and // using the definition from the ARIB STD-B67 spec) const double a = 0.17883277; const double b = 0.28466892; const double c = 0.55991073; return (0.0 > Lc) ? 0.0 : (Lc <= 1.0 / 12.0 ? sqrt(3.0 * Lc) : a * log(12.0 * Lc - b) + c); } static const av_csp_trc_function trc_funcs[AVCOL_TRC_NB] = { [AVCOL_TRC_BT709] = trc_bt709, [AVCOL_TRC_GAMMA22] = trc_gamma22, [AVCOL_TRC_GAMMA28] = trc_gamma28, [AVCOL_TRC_SMPTE170M] = trc_bt709, [AVCOL_TRC_SMPTE240M] = trc_smpte240M, [AVCOL_TRC_LINEAR] = trc_linear, [AVCOL_TRC_LOG] = trc_log, [AVCOL_TRC_LOG_SQRT] = trc_log_sqrt, [AVCOL_TRC_IEC61966_2_4] = trc_iec61966_2_4, [AVCOL_TRC_BT1361_ECG] = trc_bt1361, [AVCOL_TRC_IEC61966_2_1] = trc_iec61966_2_1, [AVCOL_TRC_BT2020_10] = trc_bt709, [AVCOL_TRC_BT2020_12] = trc_bt709, [AVCOL_TRC_SMPTE2084] = trc_smpte_st2084, [AVCOL_TRC_SMPTE428] = trc_smpte_st428_1, [AVCOL_TRC_ARIB_STD_B67] = trc_arib_std_b67, }; av_csp_trc_function av_csp_trc_func_from_id(enum AVColorTransferCharacteristic trc) { av_csp_trc_function func; if (trc >= AVCOL_TRC_NB) return NULL; func = trc_funcs[trc]; if (!func) return NULL; return func; }