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/*
* Copyright (C) 2003-2009 The Music Player Daemon Project
* 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 "pcm_volume.h"
#include "pcm_utils.h"
#include "audio_format.h"
#include <glib.h>
#include <stdint.h>
#include <string.h>
#undef G_LOG_DOMAIN
#define G_LOG_DOMAIN "pcm_volume"
static void
pcm_volume_change_8(int8_t *buffer, unsigned num_samples, int volume)
{
while (num_samples > 0) {
int32_t sample = *buffer;
sample = (sample * volume + pcm_dither() + PCM_VOLUME_1 / 2)
/ PCM_VOLUME_1;
*buffer++ = pcm_range(sample, 8);
--num_samples;
}
}
static void
pcm_volume_change_16(int16_t *buffer, unsigned num_samples, int volume)
{
while (num_samples > 0) {
int32_t sample = *buffer;
sample = (sample * volume + pcm_dither() + PCM_VOLUME_1 / 2)
/ PCM_VOLUME_1;
*buffer++ = pcm_range(sample, 16);
--num_samples;
}
}
static void
pcm_volume_change_24(int32_t *buffer, unsigned num_samples, int volume)
{
while (num_samples > 0) {
int64_t sample = *buffer;
sample = (sample * volume + pcm_dither() + PCM_VOLUME_1 / 2)
/ PCM_VOLUME_1;
*buffer++ = pcm_range(sample, 24);
--num_samples;
}
}
void
pcm_volume(char *buffer, int bufferSize,
const struct audio_format *format,
int volume)
{
if (volume == PCM_VOLUME_1)
return;
if (volume <= 0) {
memset(buffer, 0, bufferSize);
return;
}
switch (format->bits) {
case 8:
pcm_volume_change_8((int8_t *)buffer, bufferSize, volume);
break;
case 16:
pcm_volume_change_16((int16_t *)buffer, bufferSize / 2,
volume);
break;
case 24:
pcm_volume_change_24((int32_t*)buffer, bufferSize / 4,
volume);
break;
default:
g_error("%u bits not supported by pcm_volume!\n",
format->bits);
}
}
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