src/pcm_dither.h

   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 #ifndef MPD_PCM_DITHER_H
  21 #define MPD_PCM_DITHER_H
  22
  23 #include <stdint.h>
  24
  25 struct pcm_dither {
  26         int32_t error[3];
  27         int32_t random;
  28 };
  29
  30 static inline void
  31 pcm_dither_24_init(struct pcm_dither *dither)
  32 {
  33         dither->error[0] = dither->error[1] = dither->error[2] = 0;
  34         dither->random = 0;
  35 }
  36
  37 void
  38 pcm_dither_24_to_16(struct pcm_dither *dither,
  39                     int16_t *dest, const int32_t *src,
  40                     unsigned num_samples);
  41
  42 void
  43 pcm_dither_32_to_16(struct pcm_dither *dither,
  44                     int16_t *dest, const int32_t *src,
  45                     unsigned num_samples);
  46
  47 #endif