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Diffstat (limited to 'libavutil/color_utils.c')
| -rw-r--r-- | libavutil/color_utils.c | 247 |
1 files changed, 247 insertions, 0 deletions
diff --git a/libavutil/color_utils.c b/libavutil/color_utils.c new file mode 100644 index 0000000000..6dba46a816 --- /dev/null +++ b/libavutil/color_utils.c @@ -0,0 +1,247 @@ +/* + * Copyright (c) 2015 Kevin Wheatley <kevin.j.wheatley@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 + */ + +#include <stddef.h> +#include <math.h> + +#include "common.h" +#include "libavutil/color_utils.h" +#include "libavutil/pixfmt.h" + +double avpriv_get_gamma_from_trc(enum AVColorTransferCharacteristic trc) +{ + double gamma; + switch (trc) { + case AVCOL_TRC_BT709: + case AVCOL_TRC_SMPTE170M: + case AVCOL_TRC_SMPTE240M: + case AVCOL_TRC_BT1361_ECG: + case AVCOL_TRC_BT2020_10: + case AVCOL_TRC_BT2020_12: + /* these share a segmented TRC, but gamma 1.961 is a close + approximation, and also more correct for decoding content */ + gamma = 1.961; + break; + case AVCOL_TRC_GAMMA22: + case AVCOL_TRC_IEC61966_2_1: + gamma = 2.2; + break; + case AVCOL_TRC_GAMMA28: + gamma = 2.8; + break; + case AVCOL_TRC_LINEAR: + gamma = 1.0; + break; + default: + gamma = 0.0; // Unknown value representation + } + return gamma; +} + +#define BT709_alpha 1.099296826809442 +#define BT709_beta 0.018053968510807 + +static double avpriv_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 avpriv_trc_gamma22(double Lc) +{ + return (0.0 > Lc) ? 0.0 : pow(Lc, 1.0/ 2.2); +} + +static double avpriv_trc_gamma28(double Lc) +{ + return (0.0 > Lc) ? 0.0 : pow(Lc, 1.0/ 2.8); +} + +static double avpriv_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 avpriv_trc_linear(double Lc) +{ + return Lc; +} + +static double avpriv_trc_log(double Lc) +{ + return (0.01 > Lc) ? 0.0 : 1.0 + log10(Lc) / 2.0; +} + +static double avpriv_trc_log_sqrt(double Lc) +{ + // sqrt(10) / 1000 + return (0.00316227766 > Lc) ? 0.0 : 1.0 + log10(Lc) / 2.5; +} + +static double avpriv_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 avpriv_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 avpriv_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 avpriv_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 avpriv_trc_smpte_st428_1(double Lc) +{ + return (0.0 > Lc) ? 0.0 + : pow(48.0 * Lc / 52.37, 1.0 / 2.6); +} + +avpriv_trc_function avpriv_get_trc_function_from_trc(enum AVColorTransferCharacteristic trc) +{ + avpriv_trc_function func = NULL; + switch (trc) { + case AVCOL_TRC_BT709: + case AVCOL_TRC_SMPTE170M: + case AVCOL_TRC_BT2020_10: + case AVCOL_TRC_BT2020_12: + func = avpriv_trc_bt709; + break; + + case AVCOL_TRC_GAMMA22: + func = avpriv_trc_gamma22; + break; + case AVCOL_TRC_GAMMA28: + func = avpriv_trc_gamma28; + break; + + case AVCOL_TRC_SMPTE240M: + func = avpriv_trc_smpte240M; + break; + + case AVCOL_TRC_LINEAR: + func = avpriv_trc_linear; + break; + + case AVCOL_TRC_LOG: + func = avpriv_trc_log; + break; + + case AVCOL_TRC_LOG_SQRT: + func = avpriv_trc_log_sqrt; + break; + + case AVCOL_TRC_IEC61966_2_4: + func = avpriv_trc_iec61966_2_4; + break; + + case AVCOL_TRC_BT1361_ECG: + func = avpriv_trc_bt1361; + break; + + case AVCOL_TRC_IEC61966_2_1: + func = avpriv_trc_iec61966_2_1; + break; + + case AVCOL_TRC_SMPTEST2084: + func = avpriv_trc_smpte_st2084; + break; + + case AVCOL_TRC_SMPTEST428_1: + func = avpriv_trc_smpte_st428_1; + break; + + case AVCOL_TRC_RESERVED0: + case AVCOL_TRC_UNSPECIFIED: + case AVCOL_TRC_RESERVED: + default: + break; + } + return func; +} + +#ifdef TEST +// LCOV_EXCL_START + +int main(int argc, char *argv[]) +{ + int i, j; + static const double test_data[] = { + -0.1, -0.018053968510807, -0.01, -0.00449, 0.0, 0.00316227760, 0.005, + 0.009, 0.015, 0.1, 1.0, 52.37, 125.098765, 1999.11123, 6945.443, + 15123.4567, 19845.88923, 98678.4231, 99999.899998 + }; + + for(i = 0; i < AVCOL_TRC_NB; i++) { + avpriv_trc_function func = avpriv_get_trc_function_from_trc(i); + for(j = 0; j < FF_ARRAY_ELEMS(test_data); j++) { + if(func != NULL) { + double result = func(test_data[j]); + printf("AVColorTransferCharacteristic=%d calling func(%f) expected=%f\n", + i, test_data[j], result); + } + } + } + +} + +// LCOV_EXCL_STOP +#endif |