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Diffstat (limited to '3rdparty/libflac/src/plugin_common/dither.c')
-rw-r--r--3rdparty/libflac/src/plugin_common/dither.c262
1 files changed, 262 insertions, 0 deletions
diff --git a/3rdparty/libflac/src/plugin_common/dither.c b/3rdparty/libflac/src/plugin_common/dither.c
new file mode 100644
index 00000000000..538a28029e0
--- /dev/null
+++ b/3rdparty/libflac/src/plugin_common/dither.c
@@ -0,0 +1,262 @@
+/* plugin_common - Routines common to several plugins
+ * Copyright (C) 2002,2003,2004,2005,2006,2007 Josh Coalson
+ *
+ * dithering routine derived from (other GPLed source):
+ * mad - MPEG audio decoder
+ * Copyright (C) 2000-2001 Robert Leslie
+ *
+ * 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.
+ */
+
+#if HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#include "dither.h"
+#include "FLAC/assert.h"
+
+#ifdef max
+#undef max
+#endif
+#define max(a,b) ((a)>(b)?(a):(b))
+
+#ifndef FLaC__INLINE
+#define FLaC__INLINE
+#endif
+
+
+/* 32-bit pseudo-random number generator
+ *
+ * @@@ According to Miroslav, this one is poor quality, the one from the
+ * @@@ original replaygain code is much better
+ */
+static FLaC__INLINE FLAC__uint32 prng(FLAC__uint32 state)
+{
+ return (state * 0x0019660dL + 0x3c6ef35fL) & 0xffffffffL;
+}
+
+/* dither routine derived from MAD winamp plugin */
+
+typedef struct {
+ FLAC__int32 error[3];
+ FLAC__int32 random;
+} dither_state;
+
+static FLaC__INLINE FLAC__int32 linear_dither(unsigned source_bps, unsigned target_bps, FLAC__int32 sample, dither_state *dither, const FLAC__int32 MIN, const FLAC__int32 MAX)
+{
+ unsigned scalebits;
+ FLAC__int32 output, mask, random;
+
+ FLAC__ASSERT(source_bps < 32);
+ FLAC__ASSERT(target_bps <= 24);
+ FLAC__ASSERT(target_bps <= source_bps);
+
+ /* noise shape */
+ sample += dither->error[0] - dither->error[1] + dither->error[2];
+
+ dither->error[2] = dither->error[1];
+ dither->error[1] = dither->error[0] / 2;
+
+ /* bias */
+ output = sample + (1L << (source_bps - target_bps - 1));
+
+ scalebits = source_bps - target_bps;
+ mask = (1L << scalebits) - 1;
+
+ /* dither */
+ random = (FLAC__int32)prng(dither->random);
+ output += (random & mask) - (dither->random & mask);
+
+ dither->random = random;
+
+ /* clip */
+ if(output > MAX) {
+ output = MAX;
+
+ if(sample > MAX)
+ sample = MAX;
+ }
+ else if(output < MIN) {
+ output = MIN;
+
+ if(sample < MIN)
+ sample = MIN;
+ }
+
+ /* quantize */
+ output &= ~mask;
+
+ /* error feedback */
+ dither->error[0] = sample - output;
+
+ /* scale */
+ return output >> scalebits;
+}
+
+size_t FLAC__plugin_common__pack_pcm_signed_big_endian(FLAC__byte *data, const FLAC__int32 * const input[], unsigned wide_samples, unsigned channels, unsigned source_bps, unsigned target_bps)
+{
+ static dither_state dither[FLAC_PLUGIN__MAX_SUPPORTED_CHANNELS];
+ FLAC__byte * const start = data;
+ FLAC__int32 sample;
+ const FLAC__int32 *input_;
+ unsigned samples, channel;
+ const unsigned bytes_per_sample = target_bps / 8;
+ const unsigned incr = bytes_per_sample * channels;
+
+ FLAC__ASSERT(channels > 0 && channels <= FLAC_PLUGIN__MAX_SUPPORTED_CHANNELS);
+ FLAC__ASSERT(source_bps < 32);
+ FLAC__ASSERT(target_bps <= 24);
+ FLAC__ASSERT(target_bps <= source_bps);
+ FLAC__ASSERT((source_bps & 7) == 0);
+ FLAC__ASSERT((target_bps & 7) == 0);
+
+ if(source_bps != target_bps) {
+ const FLAC__int32 MIN = -(1L << (source_bps - 1));
+ const FLAC__int32 MAX = ~MIN; /*(1L << (source_bps-1)) - 1 */
+
+ for(channel = 0; channel < channels; channel++) {
+
+ samples = wide_samples;
+ data = start + bytes_per_sample * channel;
+ input_ = input[channel];
+
+ while(samples--) {
+ sample = linear_dither(source_bps, target_bps, *input_++, &dither[channel], MIN, MAX);
+
+ switch(target_bps) {
+ case 8:
+ data[0] = sample ^ 0x80;
+ break;
+ case 16:
+ data[0] = (FLAC__byte)(sample >> 8);
+ data[1] = (FLAC__byte)sample;
+ break;
+ case 24:
+ data[0] = (FLAC__byte)(sample >> 16);
+ data[1] = (FLAC__byte)(sample >> 8);
+ data[2] = (FLAC__byte)sample;
+ break;
+ }
+
+ data += incr;
+ }
+ }
+ }
+ else {
+ for(channel = 0; channel < channels; channel++) {
+ samples = wide_samples;
+ data = start + bytes_per_sample * channel;
+ input_ = input[channel];
+
+ while(samples--) {
+ sample = *input_++;
+
+ switch(target_bps) {
+ case 8:
+ data[0] = sample ^ 0x80;
+ break;
+ case 16:
+ data[0] = (FLAC__byte)(sample >> 8);
+ data[1] = (FLAC__byte)sample;
+ break;
+ case 24:
+ data[0] = (FLAC__byte)(sample >> 16);
+ data[1] = (FLAC__byte)(sample >> 8);
+ data[2] = (FLAC__byte)sample;
+ break;
+ }
+
+ data += incr;
+ }
+ }
+ }
+
+ return wide_samples * channels * (target_bps/8);
+}
+
+size_t FLAC__plugin_common__pack_pcm_signed_little_endian(FLAC__byte *data, const FLAC__int32 * const input[], unsigned wide_samples, unsigned channels, unsigned source_bps, unsigned target_bps)
+{
+ static dither_state dither[FLAC_PLUGIN__MAX_SUPPORTED_CHANNELS];
+ FLAC__byte * const start = data;
+ FLAC__int32 sample;
+ const FLAC__int32 *input_;
+ unsigned samples, channel;
+ const unsigned bytes_per_sample = target_bps / 8;
+ const unsigned incr = bytes_per_sample * channels;
+
+ FLAC__ASSERT(channels > 0 && channels <= FLAC_PLUGIN__MAX_SUPPORTED_CHANNELS);
+ FLAC__ASSERT(source_bps < 32);
+ FLAC__ASSERT(target_bps <= 24);
+ FLAC__ASSERT(target_bps <= source_bps);
+ FLAC__ASSERT((source_bps & 7) == 0);
+ FLAC__ASSERT((target_bps & 7) == 0);
+
+ if(source_bps != target_bps) {
+ const FLAC__int32 MIN = -(1L << (source_bps - 1));
+ const FLAC__int32 MAX = ~MIN; /*(1L << (source_bps-1)) - 1 */
+
+ for(channel = 0; channel < channels; channel++) {
+
+ samples = wide_samples;
+ data = start + bytes_per_sample * channel;
+ input_ = input[channel];
+
+ while(samples--) {
+ sample = linear_dither(source_bps, target_bps, *input_++, &dither[channel], MIN, MAX);
+
+ switch(target_bps) {
+ case 8:
+ data[0] = sample ^ 0x80;
+ break;
+ case 24:
+ data[2] = (FLAC__byte)(sample >> 16);
+ /* fall through */
+ case 16:
+ data[1] = (FLAC__byte)(sample >> 8);
+ data[0] = (FLAC__byte)sample;
+ }
+
+ data += incr;
+ }
+ }
+ }
+ else {
+ for(channel = 0; channel < channels; channel++) {
+ samples = wide_samples;
+ data = start + bytes_per_sample * channel;
+ input_ = input[channel];
+
+ while(samples--) {
+ sample = *input_++;
+
+ switch(target_bps) {
+ case 8:
+ data[0] = sample ^ 0x80;
+ break;
+ case 24:
+ data[2] = (FLAC__byte)(sample >> 16);
+ /* fall through */
+ case 16:
+ data[1] = (FLAC__byte)(sample >> 8);
+ data[0] = (FLAC__byte)sample;
+ }
+
+ data += incr;
+ }
+ }
+ }
+
+ return wide_samples * channels * (target_bps/8);
+}