src/replayGain.c

   1 /* the Music Player Daemon (MPD)
   2  * Copyright (C) 2003-2007 by Warren Dukes (warren.dukes@gmail.com)
   3  * (c)2004 replayGain code by AliasMrJones
   4  * This project's homepage is: http://www.musicpd.org
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  18  */
  19
  20 #include "replayGain.h"
  21 #include "utils.h"
  22
  23 #include "log.h"
  24 #include "conf.h"
  25
  26 #include <string.h>
  27 #include <math.h>
  28 #include <stdlib.h>
  29
  30 /* Added 4/14/2004 by AliasMrJones */
  31 int replayGainState = REPLAYGAIN_OFF;
  32
  33 static float replayGainPreamp = 1.0;
  34
  35 void initReplayGainState(void)
  36 {
  37         ConfigParam *param = getConfigParam(CONF_REPLAYGAIN);
  38
  39         if (!param)
  40                 return;
  41
  42         if (strcmp(param->value, "track") == 0) {
  43                 replayGainState = REPLAYGAIN_TRACK;
  44         } else if (strcmp(param->value, "album") == 0) {
  45                 replayGainState = REPLAYGAIN_ALBUM;
  46         } else {
  47                 FATAL("replaygain value \"%s\" at line %i is invalid\n",
  48                       param->value, param->line);
  49         }
  50
  51         param = getConfigParam(CONF_REPLAYGAIN_PREAMP);
  52
  53         if (param) {
  54                 char *test;
  55                 float f = strtod(param->value, &test);
  56
  57                 if (*test != '\0') {
  58                         FATAL("Replaygain preamp \"%s\" is not a number at "
  59                               "line %i\n", param->value, param->line);
  60                 }
  61
  62                 if (f < -15 || f > 15) {
  63                         FATAL("Replaygain preamp \"%s\" is not between -15 and"
  64                               "15 at line %i\n", param->value, param->line);
  65                 }
  66
  67                 replayGainPreamp = pow(10, f / 20.0);
  68         }
  69 }
  70
  71 static float computeReplayGainScale(float gain, float peak)
  72 {
  73         float scale;
  74
  75         if (gain == 0.0)
  76                 return (1);
  77         scale = pow(10.0, gain / 20.0);
  78         scale *= replayGainPreamp;
  79         if (scale > 15.0)
  80                 scale = 15.0;
  81
  82         if (scale * peak > 1.0) {
  83                 scale = 1.0 / peak;
  84         }
  85         return (scale);
  86 }
  87
  88 ReplayGainInfo *newReplayGainInfo(void)
  89 {
  90         ReplayGainInfo *ret = xmalloc(sizeof(ReplayGainInfo));
  91
  92         ret->albumGain = 0.0;
  93         ret->albumPeak = 0.0;
  94
  95         ret->trackGain = 0.0;
  96         ret->trackPeak = 0.0;
  97
  98         /* set to -1 so that we know in doReplayGain to compute the scale */
  99         ret->scale = -1.0;
 100
 101         return ret;
 102 }
 103
 104 void freeReplayGainInfo(ReplayGainInfo * info)
 105 {
 106         free(info);
 107 }
 108
 109 void doReplayGain(ReplayGainInfo * info, char *buffer, int bufferSize,
 110                   AudioFormat * format)
 111 {
 112         mpd_sint16 *buffer16;
 113         mpd_sint8 *buffer8;
 114         mpd_sint32 temp32;
 115         float scale;
 116
 117         if (replayGainState == REPLAYGAIN_OFF || !info)
 118                 return;
 119
 120         if (info->scale < 0) {
 121                 switch (replayGainState) {
 122                 case REPLAYGAIN_TRACK:
 123                         DEBUG("computing ReplayGain track scale with gain %f, "
 124                               "peak %f\n", info->trackGain, info->trackPeak);
 125                         info->scale = computeReplayGainScale(info->trackGain,
 126                                                              info->trackPeak);
 127                         break;
 128                 default:
 129                         DEBUG("computing ReplayGain album scale with gain %f, "
 130                               "peak %f\n", info->albumGain, info->albumPeak);
 131                         info->scale = computeReplayGainScale(info->albumGain,
 132                                                              info->albumPeak);
 133                         break;
 134                 }
 135         }
 136
 137         if (info->scale <= 1.01 && info->scale >= 0.99)
 138                 return;
 139
 140         buffer16 = (mpd_sint16 *) buffer;
 141         buffer8 = (mpd_sint8 *) buffer;
 142
 143         scale = info->scale;
 144
 145         switch (format->bits) {
 146         case 16:
 147                 while (bufferSize > 0) {
 148                         temp32 = *buffer16;
 149                         temp32 *= scale;
 150                         *buffer16 = temp32 > 32767 ? 32767 :
 151                             (temp32 < -32768 ? -32768 : temp32);
 152                         buffer16++;
 153                         bufferSize -= 2;
 154                 }
 155                 break;
 156         case 8:
 157                 while (bufferSize > 0) {
 158                         temp32 = *buffer8;
 159                         temp32 *= scale;
 160                         *buffer8 = temp32 > 127 ? 127 :
 161                             (temp32 < -128 ? -128 : temp32);
 162                         buffer8++;
 163                         bufferSize--;
 164                 }
 165                 break;
 166         default:
 167                 ERROR("%i bits not supported by doReplaygain!\n", format->bits);
 168         }
 169 }