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-rw-r--r--src/pcm_volume.c105
1 files changed, 105 insertions, 0 deletions
diff --git a/src/pcm_volume.c b/src/pcm_volume.c
new file mode 100644
index 000000000..af7916b1f
--- /dev/null
+++ b/src/pcm_volume.c
@@ -0,0 +1,105 @@
+/*
+ * 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);
+ }
+}