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/* libFLAC - Free Lossless Audio Codec library
* Copyright (C) 2000,2001 Josh Coalson
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library 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
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
#include <assert.h>
#include <math.h>
#include "private/fixed.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 int32 data[], unsigned data_len, real residual_bits_per_sample[FLAC__MAX_FIXED_ORDER+1])
{
int32 last_error_0 = data[-1];
int32 last_error_1 = data[-1] - data[-2];
int32 last_error_2 = last_error_1 - (data[-2] - data[-3]);
int32 last_error_3 = last_error_2 - (data[-2] - 2*data[-3] + data[-4]);
int32 error, save;
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;
residual_bits_per_sample[0] = (real)((data_len > 0 && total_error_0 > 0) ? log(M_LN2 * (real)total_error_0 / (real) data_len) / M_LN2 : 0.0);
residual_bits_per_sample[1] = (real)((data_len > 0 && total_error_1 > 0) ? log(M_LN2 * (real)total_error_1 / (real) data_len) / M_LN2 : 0.0);
residual_bits_per_sample[2] = (real)((data_len > 0 && total_error_2 > 0) ? log(M_LN2 * (real)total_error_2 / (real) data_len) / M_LN2 : 0.0);
residual_bits_per_sample[3] = (real)((data_len > 0 && total_error_3 > 0) ? log(M_LN2 * (real)total_error_3 / (real) data_len) / M_LN2 : 0.0);
residual_bits_per_sample[4] = (real)((data_len > 0 && total_error_4 > 0) ? log(M_LN2 * (real)total_error_4 / (real) data_len) / M_LN2 : 0.0);
return order;
}
unsigned FLAC__fixed_compute_best_predictor_slow(const int32 data[], unsigned data_len, real residual_bits_per_sample[FLAC__MAX_FIXED_ORDER+1])
{
int32 last_error_0 = data[-1];
int32 last_error_1 = data[-1] - data[-2];
int32 last_error_2 = last_error_1 - (data[-2] - data[-3]);
int32 last_error_3 = last_error_2 - (data[-2] - 2*data[-3] + data[-4]);
int32 error, save;
/* total_error_* are 64-bits to avoid overflow when encoding
* erratic signals when the bits-per-sample and blocksize are
* large.
*/
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|) */
#ifdef _MSC_VER
/* with VC++ you have to spoon feed it the casting */
residual_bits_per_sample[0] = (real)((data_len > 0 && total_error_0 > 0) ? log(M_LN2 * (real)(int64)total_error_0 / (real) data_len) / M_LN2 : 0.0);
residual_bits_per_sample[1] = (real)((data_len > 0 && total_error_1 > 0) ? log(M_LN2 * (real)(int64)total_error_1 / (real) data_len) / M_LN2 : 0.0);
residual_bits_per_sample[2] = (real)((data_len > 0 && total_error_2 > 0) ? log(M_LN2 * (real)(int64)total_error_2 / (real) data_len) / M_LN2 : 0.0);
residual_bits_per_sample[3] = (real)((data_len > 0 && total_error_3 > 0) ? log(M_LN2 * (real)(int64)total_error_3 / (real) data_len) / M_LN2 : 0.0);
residual_bits_per_sample[4] = (real)((data_len > 0 && total_error_4 > 0) ? log(M_LN2 * (real)(int64)total_error_4 / (real) data_len) / M_LN2 : 0.0);
#else
residual_bits_per_sample[0] = (real)((data_len > 0 && total_error_0 > 0) ? log(M_LN2 * (real)total_error_0 / (real) data_len) / M_LN2 : 0.0);
residual_bits_per_sample[1] = (real)((data_len > 0 && total_error_1 > 0) ? log(M_LN2 * (real)total_error_1 / (real) data_len) / M_LN2 : 0.0);
residual_bits_per_sample[2] = (real)((data_len > 0 && total_error_2 > 0) ? log(M_LN2 * (real)total_error_2 / (real) data_len) / M_LN2 : 0.0);
residual_bits_per_sample[3] = (real)((data_len > 0 && total_error_3 > 0) ? log(M_LN2 * (real)total_error_3 / (real) data_len) / M_LN2 : 0.0);
residual_bits_per_sample[4] = (real)((data_len > 0 && total_error_4 > 0) ? log(M_LN2 * (real)total_error_4 / (real) data_len) / M_LN2 : 0.0);
#endif
return order;
}
void FLAC__fixed_compute_residual(const int32 data[], unsigned data_len, unsigned order, int32 residual[])
{
int i, idata_len = (int)data_len;
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:
assert(0);
}
}
void FLAC__fixed_restore_signal(const int32 residual[], unsigned data_len, unsigned order, 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:
assert(0);
}
}
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