| /* |
| * 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 "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; |
| } |