/*
  * 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;
 }