src/replay_gain_info.c

   1 /*
   2  * Copyright (C) 2003-2010 The Music Player Daemon Project
   3  * http://www.musicpd.org
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  18  */
  19
  20 #include "config.h"
  21 #include "replay_gain_info.h"
  22
  23 float
  24 replay_gain_tuple_scale(const struct replay_gain_tuple *tuple, float preamp)
  25 {
  26         float scale;
  27
  28         scale = pow(10.0, tuple->gain / 20.0);
  29         scale *= preamp;
  30         if (scale > 15.0)
  31                 scale = 15.0;
  32
  33         if (scale * tuple->peak > 1.0)
  34                 scale = 1.0 / tuple->peak;
  35
  36         return scale;
  37 }
  38
  39 void
  40 replay_gain_info_complete(struct replay_gain_info *info)
  41 {
  42         if (!replay_gain_tuple_defined(&info->tuples[REPLAY_GAIN_ALBUM]))
  43                 info->tuples[REPLAY_GAIN_ALBUM] =
  44                         info->tuples[REPLAY_GAIN_TRACK];
  45 }