ref: 688c1f15cdaa5fcad19d9fddb30e1c555bfc59e0
dir: /sys/src/cmd/audio/libFLAC/fixed.c/
/* libFLAC - Free Lossless Audio Codec library
* Copyright (C) 2000,2001,2002,2003,2004 Josh Coalson
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* - Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* - Neither the name of the Xiph.org Foundation nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <math.h>
#include "private/fixed.h"
#include "FLAC/assert.h"
#ifndef M_LN2
/* math.h in VC++ doesn't seem to have this (how Microsoft is that?) */
#define M_LN2 0.69314718055994530942
#endif
#ifdef min
#undef min
#endif
#define min(x,y) ((x) < (y)? (x) : (y))
#ifdef local_abs
#undef local_abs
#endif
#define local_abs(x) ((unsigned)((x)<0? -(x) : (x)))
unsigned FLAC__fixed_compute_best_predictor(const FLAC__int32 data[], unsigned data_len, FLAC__real residual_bits_per_sample[FLAC__MAX_FIXED_ORDER+1])
{
FLAC__int32 last_error_0 = data[-1];
FLAC__int32 last_error_1 = data[-1] - data[-2];
FLAC__int32 last_error_2 = last_error_1 - (data[-2] - data[-3]);
FLAC__int32 last_error_3 = last_error_2 - (data[-2] - 2*data[-3] + data[-4]);
FLAC__int32 error, save;
FLAC__uint32 total_error_0 = 0, total_error_1 = 0, total_error_2 = 0, total_error_3 = 0, total_error_4 = 0;
unsigned i, order;
for(i = 0; i < data_len; i++) {
error = data[i] ; total_error_0 += local_abs(error); save = error;
error -= last_error_0; total_error_1 += local_abs(error); last_error_0 = save; save = error;
error -= last_error_1; total_error_2 += local_abs(error); last_error_1 = save; save = error;
error -= last_error_2; total_error_3 += local_abs(error); last_error_2 = save; save = error;
error -= last_error_3; total_error_4 += local_abs(error); last_error_3 = save;
}
if(total_error_0 < min(min(min(total_error_1, total_error_2), total_error_3), total_error_4))
order = 0;
else if(total_error_1 < min(min(total_error_2, total_error_3), total_error_4))
order = 1;
else if(total_error_2 < min(total_error_3, total_error_4))
order = 2;
else if(total_error_3 < total_error_4)
order = 3;
else
order = 4;
/* Estimate the expected number of bits per residual signal sample. */
/* 'total_error*' is linearly related to the variance of the residual */
/* signal, so we use it directly to compute E(|x|) */
FLAC__ASSERT(data_len > 0 || total_error_0 == 0);
FLAC__ASSERT(data_len > 0 || total_error_1 == 0);
FLAC__ASSERT(data_len > 0 || total_error_2 == 0);
FLAC__ASSERT(data_len > 0 || total_error_3 == 0);
FLAC__ASSERT(data_len > 0 || total_error_4 == 0);
residual_bits_per_sample[0] = (FLAC__real)((total_error_0 > 0) ? log(M_LN2 * (double)total_error_0 / (double)data_len) / M_LN2 : 0.0);
residual_bits_per_sample[1] = (FLAC__real)((total_error_1 > 0) ? log(M_LN2 * (double)total_error_1 / (double)data_len) / M_LN2 : 0.0);
residual_bits_per_sample[2] = (FLAC__real)((total_error_2 > 0) ? log(M_LN2 * (double)total_error_2 / (double)data_len) / M_LN2 : 0.0);
residual_bits_per_sample[3] = (FLAC__real)((total_error_3 > 0) ? log(M_LN2 * (double)total_error_3 / (double)data_len) / M_LN2 : 0.0);
residual_bits_per_sample[4] = (FLAC__real)((total_error_4 > 0) ? log(M_LN2 * (double)total_error_4 / (double)data_len) / M_LN2 : 0.0);
return order;
}
unsigned FLAC__fixed_compute_best_predictor_wide(const FLAC__int32 data[], unsigned data_len, FLAC__real residual_bits_per_sample[FLAC__MAX_FIXED_ORDER+1])
{
FLAC__int32 last_error_0 = data[-1];
FLAC__int32 last_error_1 = data[-1] - data[-2];
FLAC__int32 last_error_2 = last_error_1 - (data[-2] - data[-3]);
FLAC__int32 last_error_3 = last_error_2 - (data[-2] - 2*data[-3] + data[-4]);
FLAC__int32 error, save;
/* total_error_* are 64-bits to avoid overflow when encoding
* erratic signals when the bits-per-sample and blocksize are
* large.
*/
FLAC__uint64 total_error_0 = 0, total_error_1 = 0, total_error_2 = 0, total_error_3 = 0, total_error_4 = 0;
unsigned i, order;
for(i = 0; i < data_len; i++) {
error = data[i] ; total_error_0 += local_abs(error); save = error;
error -= last_error_0; total_error_1 += local_abs(error); last_error_0 = save; save = error;
error -= last_error_1; total_error_2 += local_abs(error); last_error_1 = save; save = error;
error -= last_error_2; total_error_3 += local_abs(error); last_error_2 = save; save = error;
error -= last_error_3; total_error_4 += local_abs(error); last_error_3 = save;
}
if(total_error_0 < min(min(min(total_error_1, total_error_2), total_error_3), total_error_4))
order = 0;
else if(total_error_1 < min(min(total_error_2, total_error_3), total_error_4))
order = 1;
else if(total_error_2 < min(total_error_3, total_error_4))
order = 2;
else if(total_error_3 < total_error_4)
order = 3;
else
order = 4;
/* Estimate the expected number of bits per residual signal sample. */
/* 'total_error*' is linearly related to the variance of the residual */
/* signal, so we use it directly to compute E(|x|) */
FLAC__ASSERT(data_len > 0 || total_error_0 == 0);
FLAC__ASSERT(data_len > 0 || total_error_1 == 0);
FLAC__ASSERT(data_len > 0 || total_error_2 == 0);
FLAC__ASSERT(data_len > 0 || total_error_3 == 0);
FLAC__ASSERT(data_len > 0 || total_error_4 == 0);
#if defined _MSC_VER || defined __MINGW32__
/* with VC++ you have to spoon feed it the casting */
residual_bits_per_sample[0] = (FLAC__real)((total_error_0 > 0) ? log(M_LN2 * (double)(FLAC__int64)total_error_0 / (double)data_len) / M_LN2 : 0.0);
residual_bits_per_sample[1] = (FLAC__real)((total_error_1 > 0) ? log(M_LN2 * (double)(FLAC__int64)total_error_1 / (double)data_len) / M_LN2 : 0.0);
residual_bits_per_sample[2] = (FLAC__real)((total_error_2 > 0) ? log(M_LN2 * (double)(FLAC__int64)total_error_2 / (double)data_len) / M_LN2 : 0.0);
residual_bits_per_sample[3] = (FLAC__real)((total_error_3 > 0) ? log(M_LN2 * (double)(FLAC__int64)total_error_3 / (double)data_len) / M_LN2 : 0.0);
residual_bits_per_sample[4] = (FLAC__real)((total_error_4 > 0) ? log(M_LN2 * (double)(FLAC__int64)total_error_4 / (double)data_len) / M_LN2 : 0.0);
#else
residual_bits_per_sample[0] = (FLAC__real)((total_error_0 > 0) ? log(M_LN2 * (double)total_error_0 / (double)data_len) / M_LN2 : 0.0);
residual_bits_per_sample[1] = (FLAC__real)((total_error_1 > 0) ? log(M_LN2 * (double)total_error_1 / (double)data_len) / M_LN2 : 0.0);
residual_bits_per_sample[2] = (FLAC__real)((total_error_2 > 0) ? log(M_LN2 * (double)total_error_2 / (double)data_len) / M_LN2 : 0.0);
residual_bits_per_sample[3] = (FLAC__real)((total_error_3 > 0) ? log(M_LN2 * (double)total_error_3 / (double)data_len) / M_LN2 : 0.0);
residual_bits_per_sample[4] = (FLAC__real)((total_error_4 > 0) ? log(M_LN2 * (double)total_error_4 / (double)data_len) / M_LN2 : 0.0);
#endif
return order;
}
void FLAC__fixed_compute_residual(const FLAC__int32 data[], unsigned data_len, unsigned order, FLAC__int32 residual[])
{
const int idata_len = (int)data_len;
int i;
switch(order) {
case 0:
for(i = 0; i < idata_len; i++) {
residual[i] = data[i];
}
break;
case 1:
for(i = 0; i < idata_len; i++) {
residual[i] = data[i] - data[i-1];
}
break;
case 2:
for(i = 0; i < idata_len; i++) {
/* == data[i] - 2*data[i-1] + data[i-2] */
residual[i] = data[i] - (data[i-1] << 1) + data[i-2];
}
break;
case 3:
for(i = 0; i < idata_len; i++) {
/* == data[i] - 3*data[i-1] + 3*data[i-2] - data[i-3] */
residual[i] = data[i] - (((data[i-1]-data[i-2])<<1) + (data[i-1]-data[i-2])) - data[i-3];
}
break;
case 4:
for(i = 0; i < idata_len; i++) {
/* == data[i] - 4*data[i-1] + 6*data[i-2] - 4*data[i-3] + data[i-4] */
residual[i] = data[i] - ((data[i-1]+data[i-3])<<2) + ((data[i-2]<<2) + (data[i-2]<<1)) + data[i-4];
}
break;
default:
FLAC__ASSERT(0);
}
}
void FLAC__fixed_restore_signal(const FLAC__int32 residual[], unsigned data_len, unsigned order, FLAC__int32 data[])
{
int i, idata_len = (int)data_len;
switch(order) {
case 0:
for(i = 0; i < idata_len; i++) {
data[i] = residual[i];
}
break;
case 1:
for(i = 0; i < idata_len; i++) {
data[i] = residual[i] + data[i-1];
}
break;
case 2:
for(i = 0; i < idata_len; i++) {
/* == residual[i] + 2*data[i-1] - data[i-2] */
data[i] = residual[i] + (data[i-1]<<1) - data[i-2];
}
break;
case 3:
for(i = 0; i < idata_len; i++) {
/* residual[i] + 3*data[i-1] - 3*data[i-2]) + data[i-3] */
data[i] = residual[i] + (((data[i-1]-data[i-2])<<1) + (data[i-1]-data[i-2])) + data[i-3];
}
break;
case 4:
for(i = 0; i < idata_len; i++) {
/* == residual[i] + 4*data[i-1] - 6*data[i-2] + 4*data[i-3] - data[i-4] */
data[i] = residual[i] + ((data[i-1]+data[i-3])<<2) - ((data[i-2]<<2) + (data[i-2]<<1)) - data[i-4];
}
break;
default:
FLAC__ASSERT(0);
}
}