src/pcm_utils.h

   1 /* the Music Player Daemon (MPD)
   2  * Copyright (C) 2003-2007 by Warren Dukes (warren.dukes@gmail.com)
   3  * This project's homepage is: 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  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  17  */
  18
  19 #ifndef MPD_PCM_UTILS_H
  20 #define MPD_PCM_UTILS_H
  21
  22 #include "pcm_resample.h"
  23 #include "pcm_dither.h"
  24
  25 #include <stdint.h>
  26 #include <stddef.h>
  27
  28 struct audio_format;
  29
  30 enum {
  31         /** this value means "100% volume" */
  32         PCM_VOLUME_1 = 1000,
  33 };
  34
  35 struct pcm_convert_state {
  36         struct pcm_resample_state resample;
  37
  38         struct pcm_dither_24 dither;
  39
  40         /* Strict C99 doesn't allow empty structs */
  41         int error;
  42 };
  43
  44 /**
  45  * Converts a float value (0.0 = silence, 1.0 = 100% volume) to an
  46  * integer volume value (1000 = 100%).
  47  */
  48 static inline int
  49 pcm_float_to_volume(float volume)
  50 {
  51         return volume * PCM_VOLUME_1 + 0.5;
  52 }
  53
  54 void pcm_volume(char *buffer, int bufferSize,
  55                 const struct audio_format *format,
  56                 int volume);
  57
  58 void pcm_mix(char *buffer1, const char *buffer2, size_t size,
  59              const struct audio_format *format, float portion1);
  60
  61 void pcm_convert_init(struct pcm_convert_state *state);
  62
  63 size_t pcm_convert(const struct audio_format *inFormat,
  64                    const char *inBuffer, size_t inSize,
  65                    const struct audio_format *outFormat,
  66                    char *outBuffer,
  67                    struct pcm_convert_state *convState);
  68
  69 size_t pcm_convert_size(const struct audio_format *inFormat, size_t inSize,
  70                         const struct audio_format *outFormat);
  71
  72 #endif