| /* |
| * Copyright (c) 2015 Kevin Wheatley <kevin.j.wheatley@gmail.com> |
| * Copyright (c) 2016 Ronald S. Bultje <rsbultje@gmail.com> |
| * Copyright (c) 2023 Leo Izen <leo.izen@gmail.com> |
| * |
| * 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 <rsbultje@gmail.com> |
| * @author Leo Izen <leo.izen@gmail.com> |
| * @author Kevin Wheatley <kevin.j.wheatley@gmail.com> |
| */ |
| |
| #include <stdlib.h> |
| #include <math.h> |
| |
| #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; |
| } |