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/* the Music Player Daemon (MPD)
* (c)2003-2004 by Warren Dukes (shank@mercury.chem.pitt.edu)
* (c)2004 replayGain code by AliasMrJones
* This project's homepage is: http://www.musicpd.org
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program 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 General Public License for more details.
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include "replayGain.h"
#include "log.h"
#include "conf.h"
#include <string.h>
#include <math.h>
#include <stdlib.h>
/* Added 4/14/2004 by AliasMrJones */
static int replayGainState = REPLAYGAIN_OFF;
static float replayGainPreamp = 1.0;
void initReplayGainState() {
ConfigParam * param = getConfigParam(CONF_REPLAYGAIN);
if(!param) return;
if(strcmp(param->value, "track") == 0) {
replayGainState = REPLAYGAIN_TRACK;
}
else if(strcmp(param->value, "album") == 0) {
replayGainState = REPLAYGAIN_ALBUM;
}
else {
ERROR("replaygain value \"%s\" at line %i is invalid\n",
param->value, param->line);
exit(EXIT_FAILURE);
}
param = getConfigParam(CONF_REPLAYGAIN_PREAMP);
if(param) {
char * test;
float f = strtod(param->value, &test);
if(*test != '\0') {
ERROR("Replaygain preamp \"%s\" is not a number at "
"line %i\n", param->value, param->line);
exit(EXIT_FAILURE);
}
if(f < -15 || f > 15) {
ERROR("Replaygain preamp \"%s\" is not between -15 and"
"15 at line %i\n",
param->value, param->line);
exit(EXIT_FAILURE);
}
replayGainPreamp = pow(10, f/20.0);
}
}
static float computeReplayGainScale(float gain, float peak) {
float scale;
if(gain == 0.0) return(1);
scale = pow(10.0, gain/20.0);
scale*= replayGainPreamp;
if(scale > 15.0) scale = 15.0;
if (scale * peak > 1.0) {
scale = 1.0 / peak;
}
return(scale);
}
ReplayGainInfo * newReplayGainInfo() {
ReplayGainInfo * ret = malloc(sizeof(ReplayGainInfo));
ret->albumGain = 0.0;
ret->albumPeak = 0.0;
ret->trackGain = 0.0;
ret->trackPeak = 0.0;
/* set to -1 so that we know in doReplayGain to compute the scale */
ret->scale = -1.0;
return ret;
}
void freeReplayGainInfo(ReplayGainInfo * info) {
free(info);
}
void doReplayGain(ReplayGainInfo * info, char * buffer, int bufferSize,
AudioFormat * format)
{
mpd_sint32 * buffer32 = (mpd_sint32 *)buffer;
int samples;
int shift;
int iScale;
if(format->bits!=32 || format->channels!=2 ) {
ERROR("Only 32 bit stereo is supported for doReplayGain!\n");
exit(EXIT_FAILURE);
return;
}
if(replayGainState == REPLAYGAIN_OFF || !info) return;
if(info->scale < 0) {
switch(replayGainState) {
case REPLAYGAIN_TRACK:
info->scale = computeReplayGainScale(info->trackGain,
info->trackPeak);
break;
default:
info->scale = computeReplayGainScale(info->albumGain,
info->albumPeak);
break;
}
}
samples = bufferSize >> 2;
/* 64 steps is enough - gives 0.13db resolution at 0dB and 2.5dB at -25dB*/
iScale = info->scale * 64;
shift = 6;
/* handle negative or zero scale */
if(iScale<=0) {
memset(buffer,0,bufferSize);
return;
}
/* lower shift value as much as possible */
while(!(iScale & 1) && shift) {
iScale >>= 1;
shift--;
}
/* change samples */
/* no check for overflow needed - replaygain peak info prevent
* clipping and we have 3 headroom bits in our 32 bit samples */
if(iScale == 1) {
while(samples--) {
*buffer32 = *buffer32 >> shift;
buffer32++;
}
}
else {
while(samples--) {
*buffer32 = (*buffer32 >> shift) * iScale;
buffer32++;
}
}
}
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