mirror of
https://github.com/cookiengineer/audacity
synced 2026-02-07 04:01:54 +01:00
264 lines
6.7 KiB
C
264 lines
6.7 KiB
C
/* plugin_common - Routines common to several plugins
|
|
* Copyright (C) 2002-2009 Josh Coalson
|
|
* Copyright (C) 2011-2014 Xiph.Org Foundation
|
|
*
|
|
* 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.,
|
|
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
|
|
*/
|
|
|
|
#ifdef 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__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);
|
|
}
|