ref: 511421003a44633d8907828aef280acc762cc56b
dir: /sys/src/cmd/audio/libFLAC/lpc.c/
/* libFLAC - Free Lossless Audio Codec library
* Copyright (C) 2000-2009 Josh Coalson
* Copyright (C) 2011-2022 Xiph.Org Foundation
*
* 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.
*/
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#include <math.h>
#include <stdlib.h>
#include "FLAC/assert.h"
#include "FLAC/format.h"
#include "share/compat.h"
#include "private/bitmath.h"
#include "private/lpc.h"
#include "private/macros.h"
#if !defined(NDEBUG) || defined FLAC__OVERFLOW_DETECT || defined FLAC__OVERFLOW_DETECT_VERBOSE
#include <stdio.h>
#endif
/* OPT: #undef'ing this may improve the speed on some architectures */
#define FLAC__LPC_UNROLLED_FILTER_LOOPS
#ifndef FLAC__INTEGER_ONLY_LIBRARY
#if defined(_MSC_VER) && (_MSC_VER < 1800)
#include <float.h>
#elif defined(Plan9)
#define _copysign(x,y) ((x > 0.0 && y < 0.0) || (x < 0.0 && y > 0.0)) ? -x : x
static inline long int lround(double x) {
return (long)(x + _copysign(0.5, x));
}
#elif !defined(HAVE_LROUND) && defined(__GNUC__)
static inline long int lround(double x) {
return (long)(x + __builtin_copysign(0.5, x));
}
/* If this fails, we are in the presence of a mid 90's compiler, move along... */
#endif
void FLAC__lpc_window_data(const FLAC__int32 in[], const FLAC__real window[], FLAC__real out[], uint32_t data_len)
{
uint32_t i;
for(i = 0; i < data_len; i++)
out[i] = in[i] * window[i];
}
void FLAC__lpc_window_data_wide(const FLAC__int64 in[], const FLAC__real window[], FLAC__real out[], uint32_t data_len)
{
uint32_t i;
for(i = 0; i < data_len; i++)
out[i] = in[i] * window[i];
}
void FLAC__lpc_window_data_partial(const FLAC__int32 in[], const FLAC__real window[], FLAC__real out[], uint32_t data_len, uint32_t part_size, uint32_t data_shift)
{
uint32_t i, j;
if((part_size + data_shift) < data_len){
for(i = 0; i < part_size; i++)
out[i] = in[data_shift+i] * window[i];
i = flac_min(i,data_len - part_size - data_shift);
for(j = data_len - part_size; j < data_len; i++, j++)
out[i] = in[data_shift+i] * window[j];
if(i < data_len)
out[i] = 0.0f;
}
}
void FLAC__lpc_window_data_partial_wide(const FLAC__int64 in[], const FLAC__real window[], FLAC__real out[], uint32_t data_len, uint32_t part_size, uint32_t data_shift)
{
uint32_t i, j;
if((part_size + data_shift) < data_len){
for(i = 0; i < part_size; i++)
out[i] = in[data_shift+i] * window[i];
i = flac_min(i,data_len - part_size - data_shift);
for(j = data_len - part_size; j < data_len; i++, j++)
out[i] = in[data_shift+i] * window[j];
if(i < data_len)
out[i] = 0.0f;
}
}
void FLAC__lpc_compute_autocorrelation(const FLAC__real data[], uint32_t data_len, uint32_t lag, double autoc[])
{
/* a readable, but slower, version */
#if 0
double d;
uint32_t i;
FLAC__ASSERT(lag > 0);
FLAC__ASSERT(lag <= data_len);
/*
* Technically we should subtract the mean first like so:
* for(i = 0; i < data_len; i++)
* data[i] -= mean;
* but it appears not to make enough of a difference to matter, and
* most signals are already closely centered around zero
*/
while(lag--) {
for(i = lag, d = 0.0; i < data_len; i++)
d += data[i] * (double)data[i - lag];
autoc[lag] = d;
}
#endif
/*
* this version tends to run faster because of better data locality
* ('data_len' is usually much larger than 'lag')
*/
double d;
uint32_t sample, coeff;
const uint32_t limit = data_len - lag;
FLAC__ASSERT(lag > 0);
FLAC__ASSERT(lag <= data_len);
for(coeff = 0; coeff < lag; coeff++)
autoc[coeff] = 0.0;
for(sample = 0; sample <= limit; sample++) {
d = data[sample];
for(coeff = 0; coeff < lag; coeff++)
autoc[coeff] += d * data[sample+coeff];
}
for(; sample < data_len; sample++) {
d = data[sample];
for(coeff = 0; coeff < data_len - sample; coeff++)
autoc[coeff] += d * data[sample+coeff];
}
}
void FLAC__lpc_compute_lp_coefficients(const double autoc[], uint32_t *max_order, FLAC__real lp_coeff[][FLAC__MAX_LPC_ORDER], double error[])
{
uint32_t i, j;
double r, err, lpc[FLAC__MAX_LPC_ORDER];
FLAC__ASSERT(0 != max_order);
FLAC__ASSERT(0 < *max_order);
FLAC__ASSERT(*max_order <= FLAC__MAX_LPC_ORDER);
FLAC__ASSERT(autoc[0] != 0.0);
err = autoc[0];
for(i = 0; i < *max_order; i++) {
/* Sum up this iteration's reflection coefficient. */
r = -autoc[i+1];
for(j = 0; j < i; j++)
r -= lpc[j] * autoc[i-j];
r /= err;
/* Update LPC coefficients and total error. */
lpc[i]=r;
for(j = 0; j < (i>>1); j++) {
double tmp = lpc[j];
lpc[j] += r * lpc[i-1-j];
lpc[i-1-j] += r * tmp;
}
if(i & 1)
lpc[j] += lpc[j] * r;
err *= (1.0 - r * r);
/* save this order */
for(j = 0; j <= i; j++)
lp_coeff[i][j] = (FLAC__real)(-lpc[j]); /* negate FIR filter coeff to get predictor coeff */
error[i] = err;
/* see SF bug https://sourceforge.net/p/flac/bugs/234/ */
if(err == 0.0) {
*max_order = i+1;
return;
}
}
}
int FLAC__lpc_quantize_coefficients(const FLAC__real lp_coeff[], uint32_t order, uint32_t precision, FLAC__int32 qlp_coeff[], int *shift)
{
uint32_t i;
double cmax;
FLAC__int32 qmax, qmin;
FLAC__ASSERT(precision > 0);
FLAC__ASSERT(precision >= FLAC__MIN_QLP_COEFF_PRECISION);
/* drop one bit for the sign; from here on out we consider only |lp_coeff[i]| */
precision--;
qmax = 1 << precision;
qmin = -qmax;
qmax--;
/* calc cmax = max( |lp_coeff[i]| ) */
cmax = 0.0;
for(i = 0; i < order; i++) {
const double d = fabs(lp_coeff[i]);
if(d > cmax)
cmax = d;
}
if(cmax <= 0.0) {
/* => coefficients are all 0, which means our constant-detect didn't work */
return 2;
}
else {
const int max_shiftlimit = (1 << (FLAC__SUBFRAME_LPC_QLP_SHIFT_LEN-1)) - 1;
const int min_shiftlimit = -max_shiftlimit - 1;
int log2cmax;
(void)frexp(cmax, &log2cmax);
log2cmax--;
*shift = (int)precision - log2cmax - 1;
if(*shift > max_shiftlimit)
*shift = max_shiftlimit;
else if(*shift < min_shiftlimit)
return 1;
}
if(*shift >= 0) {
double error = 0.0;
FLAC__int32 q;
for(i = 0; i < order; i++) {
error += lp_coeff[i] * (1 << *shift);
q = lround(error);
#ifdef FLAC__OVERFLOW_DETECT
if(q > qmax+1) /* we expect q==qmax+1 occasionally due to rounding */
fprintf(stderr,"FLAC__lpc_quantize_coefficients: quantizer overflow: q>qmax %d>%d shift=%d cmax=%f precision=%u lpc[%u]=%f\n",q,qmax,*shift,cmax,precision+1,i,lp_coeff[i]);
else if(q < qmin)
fprintf(stderr,"FLAC__lpc_quantize_coefficients: quantizer overflow: q<qmin %d<%d shift=%d cmax=%f precision=%u lpc[%u]=%f\n",q,qmin,*shift,cmax,precision+1,i,lp_coeff[i]);
#endif
if(q > qmax)
q = qmax;
else if(q < qmin)
q = qmin;
error -= q;
qlp_coeff[i] = q;
}
}
/* negative shift is very rare but due to design flaw, negative shift is
* not allowed in the decoder, so it must be handled specially by scaling
* down coeffs
*/
else {
const int nshift = -(*shift);
double error = 0.0;
FLAC__int32 q;
#ifndef NDEBUG
fprintf(stderr,"FLAC__lpc_quantize_coefficients: negative shift=%d order=%u cmax=%f\n", *shift, order, cmax);
#endif
for(i = 0; i < order; i++) {
error += lp_coeff[i] / (1 << nshift);
q = lround(error);
#ifdef FLAC__OVERFLOW_DETECT
if(q > qmax+1) /* we expect q==qmax+1 occasionally due to rounding */
fprintf(stderr,"FLAC__lpc_quantize_coefficients: quantizer overflow: q>qmax %d>%d shift=%d cmax=%f precision=%u lpc[%u]=%f\n",q,qmax,*shift,cmax,precision+1,i,lp_coeff[i]);
else if(q < qmin)
fprintf(stderr,"FLAC__lpc_quantize_coefficients: quantizer overflow: q<qmin %d<%d shift=%d cmax=%f precision=%u lpc[%u]=%f\n",q,qmin,*shift,cmax,precision+1,i,lp_coeff[i]);
#endif
if(q > qmax)
q = qmax;
else if(q < qmin)
q = qmin;
error -= q;
qlp_coeff[i] = q;
}
*shift = 0;
}
return 0;
}
#if defined(_MSC_VER)
// silence MSVC warnings about __restrict modifier
#pragma warning ( disable : 4028 )
#endif
void FLAC__lpc_compute_residual_from_qlp_coefficients(const FLAC__int32 * flac_restrict data, uint32_t data_len, const FLAC__int32 * flac_restrict qlp_coeff, uint32_t order, int lp_quantization, FLAC__int32 * flac_restrict residual)
#if defined(FLAC__OVERFLOW_DETECT) || !defined(FLAC__LPC_UNROLLED_FILTER_LOOPS)
{
FLAC__int64 sumo;
uint32_t i, j;
FLAC__int32 sum;
const FLAC__int32 *history;
#ifdef FLAC__OVERFLOW_DETECT_VERBOSE
fprintf(stderr,"FLAC__lpc_compute_residual_from_qlp_coefficients: data_len=%d, order=%u, lpq=%d",data_len,order,lp_quantization);
for(i=0;i<order;i++)
fprintf(stderr,", q[%u]=%d",i,qlp_coeff[i]);
fprintf(stderr,"\n");
#endif
FLAC__ASSERT(order > 0);
for(i = 0; i < data_len; i++) {
sumo = 0;
sum = 0;
history = data;
for(j = 0; j < order; j++) {
sum += qlp_coeff[j] * (*(--history));
sumo += (FLAC__int64)qlp_coeff[j] * (FLAC__int64)(*history);
if(sumo > 2147483647ll || sumo < -2147483648ll)
fprintf(stderr,"FLAC__lpc_compute_residual_from_qlp_coefficients: OVERFLOW, i=%u, j=%u, c=%d, d=%d, sumo=%" PRId64 "\n",i,j,qlp_coeff[j],*history,sumo);
}
*(residual++) = *(data++) - (sum >> lp_quantization);
}
/* Here's a slower but clearer version:
for(i = 0; i < data_len; i++) {
sum = 0;
for(j = 0; j < order; j++)
sum += qlp_coeff[j] * data[i-j-1];
residual[i] = data[i] - (sum >> lp_quantization);
}
*/
}
#else /* fully unrolled version for normal use */
{
int i;
FLAC__int32 sum;
FLAC__ASSERT(order > 0);
FLAC__ASSERT(order <= 32);
/*
* We do unique versions up to 12th order since that's the subset limit.
* Also they are roughly ordered to match frequency of occurrence to
* minimize branching.
*/
if(order <= 12) {
if(order > 8) {
if(order > 10) {
if(order == 12) {
for(i = 0; i < (int)data_len; i++) {
sum = 0;
sum += qlp_coeff[11] * data[i-12];
sum += qlp_coeff[10] * data[i-11];
sum += qlp_coeff[9] * data[i-10];
sum += qlp_coeff[8] * data[i-9];
sum += qlp_coeff[7] * data[i-8];
sum += qlp_coeff[6] * data[i-7];
sum += qlp_coeff[5] * data[i-6];
sum += qlp_coeff[4] * data[i-5];
sum += qlp_coeff[3] * data[i-4];
sum += qlp_coeff[2] * data[i-3];
sum += qlp_coeff[1] * data[i-2];
sum += qlp_coeff[0] * data[i-1];
residual[i] = data[i] - (sum >> lp_quantization);
}
}
else { /* order == 11 */
for(i = 0; i < (int)data_len; i++) {
sum = 0;
sum += qlp_coeff[10] * data[i-11];
sum += qlp_coeff[9] * data[i-10];
sum += qlp_coeff[8] * data[i-9];
sum += qlp_coeff[7] * data[i-8];
sum += qlp_coeff[6] * data[i-7];
sum += qlp_coeff[5] * data[i-6];
sum += qlp_coeff[4] * data[i-5];
sum += qlp_coeff[3] * data[i-4];
sum += qlp_coeff[2] * data[i-3];
sum += qlp_coeff[1] * data[i-2];
sum += qlp_coeff[0] * data[i-1];
residual[i] = data[i] - (sum >> lp_quantization);
}
}
}
else {
if(order == 10) {
for(i = 0; i < (int)data_len; i++) {
sum = 0;
sum += qlp_coeff[9] * data[i-10];
sum += qlp_coeff[8] * data[i-9];
sum += qlp_coeff[7] * data[i-8];
sum += qlp_coeff[6] * data[i-7];
sum += qlp_coeff[5] * data[i-6];
sum += qlp_coeff[4] * data[i-5];
sum += qlp_coeff[3] * data[i-4];
sum += qlp_coeff[2] * data[i-3];
sum += qlp_coeff[1] * data[i-2];
sum += qlp_coeff[0] * data[i-1];
residual[i] = data[i] - (sum >> lp_quantization);
}
}
else { /* order == 9 */
for(i = 0; i < (int)data_len; i++) {
sum = 0;
sum += qlp_coeff[8] * data[i-9];
sum += qlp_coeff[7] * data[i-8];
sum += qlp_coeff[6] * data[i-7];
sum += qlp_coeff[5] * data[i-6];
sum += qlp_coeff[4] * data[i-5];
sum += qlp_coeff[3] * data[i-4];
sum += qlp_coeff[2] * data[i-3];
sum += qlp_coeff[1] * data[i-2];
sum += qlp_coeff[0] * data[i-1];
residual[i] = data[i] - (sum >> lp_quantization);
}
}
}
}
else if(order > 4) {
if(order > 6) {
if(order == 8) {
for(i = 0; i < (int)data_len; i++) {
sum = 0;
sum += qlp_coeff[7] * data[i-8];
sum += qlp_coeff[6] * data[i-7];
sum += qlp_coeff[5] * data[i-6];
sum += qlp_coeff[4] * data[i-5];
sum += qlp_coeff[3] * data[i-4];
sum += qlp_coeff[2] * data[i-3];
sum += qlp_coeff[1] * data[i-2];
sum += qlp_coeff[0] * data[i-1];
residual[i] = data[i] - (sum >> lp_quantization);
}
}
else { /* order == 7 */
for(i = 0; i < (int)data_len; i++) {
sum = 0;
sum += qlp_coeff[6] * data[i-7];
sum += qlp_coeff[5] * data[i-6];
sum += qlp_coeff[4] * data[i-5];
sum += qlp_coeff[3] * data[i-4];
sum += qlp_coeff[2] * data[i-3];
sum += qlp_coeff[1] * data[i-2];
sum += qlp_coeff[0] * data[i-1];
residual[i] = data[i] - (sum >> lp_quantization);
}
}
}
else {
if(order == 6) {
for(i = 0; i < (int)data_len; i++) {
sum = 0;
sum += qlp_coeff[5] * data[i-6];
sum += qlp_coeff[4] * data[i-5];
sum += qlp_coeff[3] * data[i-4];
sum += qlp_coeff[2] * data[i-3];
sum += qlp_coeff[1] * data[i-2];
sum += qlp_coeff[0] * data[i-1];
residual[i] = data[i] - (sum >> lp_quantization);
}
}
else { /* order == 5 */
for(i = 0; i < (int)data_len; i++) {
sum = 0;
sum += qlp_coeff[4] * data[i-5];
sum += qlp_coeff[3] * data[i-4];
sum += qlp_coeff[2] * data[i-3];
sum += qlp_coeff[1] * data[i-2];
sum += qlp_coeff[0] * data[i-1];
residual[i] = data[i] - (sum >> lp_quantization);
}
}
}
}
else {
if(order > 2) {
if(order == 4) {
for(i = 0; i < (int)data_len; i++) {
sum = 0;
sum += qlp_coeff[3] * data[i-4];
sum += qlp_coeff[2] * data[i-3];
sum += qlp_coeff[1] * data[i-2];
sum += qlp_coeff[0] * data[i-1];
residual[i] = data[i] - (sum >> lp_quantization);
}
}
else { /* order == 3 */
for(i = 0; i < (int)data_len; i++) {
sum = 0;
sum += qlp_coeff[2] * data[i-3];
sum += qlp_coeff[1] * data[i-2];
sum += qlp_coeff[0] * data[i-1];
residual[i] = data[i] - (sum >> lp_quantization);
}
}
}
else {
if(order == 2) {
for(i = 0; i < (int)data_len; i++) {
sum = 0;
sum += qlp_coeff[1] * data[i-2];
sum += qlp_coeff[0] * data[i-1];
residual[i] = data[i] - (sum >> lp_quantization);
}
}
else { /* order == 1 */
for(i = 0; i < (int)data_len; i++)
residual[i] = data[i] - ((qlp_coeff[0] * data[i-1]) >> lp_quantization);
}
}
}
}
else { /* order > 12 */
for(i = 0; i < (int)data_len; i++) {
sum = 0;
switch(order) {
case 32: sum += qlp_coeff[31] * data[i-32]; /* Falls through. */
case 31: sum += qlp_coeff[30] * data[i-31]; /* Falls through. */
case 30: sum += qlp_coeff[29] * data[i-30]; /* Falls through. */
case 29: sum += qlp_coeff[28] * data[i-29]; /* Falls through. */
case 28: sum += qlp_coeff[27] * data[i-28]; /* Falls through. */
case 27: sum += qlp_coeff[26] * data[i-27]; /* Falls through. */
case 26: sum += qlp_coeff[25] * data[i-26]; /* Falls through. */
case 25: sum += qlp_coeff[24] * data[i-25]; /* Falls through. */
case 24: sum += qlp_coeff[23] * data[i-24]; /* Falls through. */
case 23: sum += qlp_coeff[22] * data[i-23]; /* Falls through. */
case 22: sum += qlp_coeff[21] * data[i-22]; /* Falls through. */
case 21: sum += qlp_coeff[20] * data[i-21]; /* Falls through. */
case 20: sum += qlp_coeff[19] * data[i-20]; /* Falls through. */
case 19: sum += qlp_coeff[18] * data[i-19]; /* Falls through. */
case 18: sum += qlp_coeff[17] * data[i-18]; /* Falls through. */
case 17: sum += qlp_coeff[16] * data[i-17]; /* Falls through. */
case 16: sum += qlp_coeff[15] * data[i-16]; /* Falls through. */
case 15: sum += qlp_coeff[14] * data[i-15]; /* Falls through. */
case 14: sum += qlp_coeff[13] * data[i-14]; /* Falls through. */
case 13: sum += qlp_coeff[12] * data[i-13];
sum += qlp_coeff[11] * data[i-12];
sum += qlp_coeff[10] * data[i-11];
sum += qlp_coeff[ 9] * data[i-10];
sum += qlp_coeff[ 8] * data[i- 9];
sum += qlp_coeff[ 7] * data[i- 8];
sum += qlp_coeff[ 6] * data[i- 7];
sum += qlp_coeff[ 5] * data[i- 6];
sum += qlp_coeff[ 4] * data[i- 5];
sum += qlp_coeff[ 3] * data[i- 4];
sum += qlp_coeff[ 2] * data[i- 3];
sum += qlp_coeff[ 1] * data[i- 2];
sum += qlp_coeff[ 0] * data[i- 1];
}
residual[i] = data[i] - (sum >> lp_quantization);
}
}
}
#endif
void FLAC__lpc_compute_residual_from_qlp_coefficients_wide(const FLAC__int32 * flac_restrict data, uint32_t data_len, const FLAC__int32 * flac_restrict qlp_coeff, uint32_t order, int lp_quantization, FLAC__int32 * flac_restrict residual)
#if defined(FLAC__OVERFLOW_DETECT) || !defined(FLAC__LPC_UNROLLED_FILTER_LOOPS)
{
uint32_t i, j;
FLAC__int64 sum;
const FLAC__int32 *history;
#ifdef FLAC__OVERFLOW_DETECT_VERBOSE
fprintf(stderr,"FLAC__lpc_compute_residual_from_qlp_coefficients_wide: data_len=%d, order=%u, lpq=%d",data_len,order,lp_quantization);
for(i=0;i<order;i++)
fprintf(stderr,", q[%u]=%d",i,qlp_coeff[i]);
fprintf(stderr,"\n");
#endif
FLAC__ASSERT(order > 0);
for(i = 0; i < data_len; i++) {
sum = 0;
history = data;
for(j = 0; j < order; j++)
sum += (FLAC__int64)qlp_coeff[j] * (FLAC__int64)(*(--history));
if(FLAC__bitmath_silog2((FLAC__int64)(*data) - (sum >> lp_quantization)) > 32) {
fprintf(stderr,"FLAC__lpc_compute_residual_from_qlp_coefficients_wide: OVERFLOW, i=%u, data=%d, sum=%" PRId64 ", residual=%" PRId64 "\n", i, *data, (int64_t)(sum >> lp_quantization), ((FLAC__int64)(*data) - (sum >> lp_quantization)));
break;
}
*(residual++) = *(data++) - (FLAC__int32)(sum >> lp_quantization);
}
}
#else /* fully unrolled version for normal use */
{
int i;
FLAC__int64 sum;
FLAC__ASSERT(order > 0);
FLAC__ASSERT(order <= 32);
/*
* We do unique versions up to 12th order since that's the subset limit.
* Also they are roughly ordered to match frequency of occurrence to
* minimize branching.
*/
if(order <= 12) {
if(order > 8) {
if(order > 10) {
if(order == 12) {
for(i = 0; i < (int)data_len; i++) {
sum = 0;
sum += qlp_coeff[11] * (FLAC__int64)data[i-12];
sum += qlp_coeff[10] * (FLAC__int64)data[i-11];
sum += qlp_coeff[9] * (FLAC__int64)data[i-10];
sum += qlp_coeff[8] * (FLAC__int64)data[i-9];
sum += qlp_coeff[7] * (FLAC__int64)data[i-8];
sum += qlp_coeff[6] * (FLAC__int64)data[i-7];
sum += qlp_coeff[5] * (FLAC__int64)data[i-6];
sum += qlp_coeff[4] * (FLAC__int64)data[i-5];
sum += qlp_coeff[3] * (FLAC__int64)data[i-4];
sum += qlp_coeff[2] * (FLAC__int64)data[i-3];
sum += qlp_coeff[1] * (FLAC__int64)data[i-2];
sum += qlp_coeff[0] * (FLAC__int64)data[i-1];
residual[i] = data[i] - (sum >> lp_quantization);
}
}
else { /* order == 11 */
for(i = 0; i < (int)data_len; i++) {
sum = 0;
sum += qlp_coeff[10] * (FLAC__int64)data[i-11];
sum += qlp_coeff[9] * (FLAC__int64)data[i-10];
sum += qlp_coeff[8] * (FLAC__int64)data[i-9];
sum += qlp_coeff[7] * (FLAC__int64)data[i-8];
sum += qlp_coeff[6] * (FLAC__int64)data[i-7];
sum += qlp_coeff[5] * (FLAC__int64)data[i-6];
sum += qlp_coeff[4] * (FLAC__int64)data[i-5];
sum += qlp_coeff[3] * (FLAC__int64)data[i-4];
sum += qlp_coeff[2] * (FLAC__int64)data[i-3];
sum += qlp_coeff[1] * (FLAC__int64)data[i-2];
sum += qlp_coeff[0] * (FLAC__int64)data[i-1];
residual[i] = data[i] - (sum >> lp_quantization);
}
}
}
else {
if(order == 10) {
for(i = 0; i < (int)data_len; i++) {
sum = 0;
sum += qlp_coeff[9] * (FLAC__int64)data[i-10];
sum += qlp_coeff[8] * (FLAC__int64)data[i-9];
sum += qlp_coeff[7] * (FLAC__int64)data[i-8];
sum += qlp_coeff[6] * (FLAC__int64)data[i-7];
sum += qlp_coeff[5] * (FLAC__int64)data[i-6];
sum += qlp_coeff[4] * (FLAC__int64)data[i-5];
sum += qlp_coeff[3] * (FLAC__int64)data[i-4];
sum += qlp_coeff[2] * (FLAC__int64)data[i-3];
sum += qlp_coeff[1] * (FLAC__int64)data[i-2];
sum += qlp_coeff[0] * (FLAC__int64)data[i-1];
residual[i] = data[i] - (sum >> lp_quantization);
}
}
else { /* order == 9 */
for(i = 0; i < (int)data_len; i++) {
sum = 0;
sum += qlp_coeff[8] * (FLAC__int64)data[i-9];
sum += qlp_coeff[7] * (FLAC__int64)data[i-8];
sum += qlp_coeff[6] * (FLAC__int64)data[i-7];
sum += qlp_coeff[5] * (FLAC__int64)data[i-6];
sum += qlp_coeff[4] * (FLAC__int64)data[i-5];
sum += qlp_coeff[3] * (FLAC__int64)data[i-4];
sum += qlp_coeff[2] * (FLAC__int64)data[i-3];
sum += qlp_coeff[1] * (FLAC__int64)data[i-2];
sum += qlp_coeff[0] * (FLAC__int64)data[i-1];
residual[i] = data[i] - (sum >> lp_quantization);
}
}
}
}
else if(order > 4) {
if(order > 6) {
if(order == 8) {
for(i = 0; i < (int)data_len; i++) {
sum = 0;
sum += qlp_coeff[7] * (FLAC__int64)data[i-8];
sum += qlp_coeff[6] * (FLAC__int64)data[i-7];
sum += qlp_coeff[5] * (FLAC__int64)data[i-6];
sum += qlp_coeff[4] * (FLAC__int64)data[i-5];
sum += qlp_coeff[3] * (FLAC__int64)data[i-4];
sum += qlp_coeff[2] * (FLAC__int64)data[i-3];
sum += qlp_coeff[1] * (FLAC__int64)data[i-2];
sum += qlp_coeff[0] * (FLAC__int64)data[i-1];
residual[i] = data[i] - (sum >> lp_quantization);
}
}
else { /* order == 7 */
for(i = 0; i < (int)data_len; i++) {
sum = 0;
sum += qlp_coeff[6] * (FLAC__int64)data[i-7];
sum += qlp_coeff[5] * (FLAC__int64)data[i-6];
sum += qlp_coeff[4] * (FLAC__int64)data[i-5];
sum += qlp_coeff[3] * (FLAC__int64)data[i-4];
sum += qlp_coeff[2] * (FLAC__int64)data[i-3];
sum += qlp_coeff[1] * (FLAC__int64)data[i-2];
sum += qlp_coeff[0] * (FLAC__int64)data[i-1];
residual[i] = data[i] - (sum >> lp_quantization);
}
}
}
else {
if(order == 6) {
for(i = 0; i < (int)data_len; i++) {
sum = 0;
sum += qlp_coeff[5] * (FLAC__int64)data[i-6];
sum += qlp_coeff[4] * (FLAC__int64)data[i-5];
sum += qlp_coeff[3] * (FLAC__int64)data[i-4];
sum += qlp_coeff[2] * (FLAC__int64)data[i-3];
sum += qlp_coeff[1] * (FLAC__int64)data[i-2];
sum += qlp_coeff[0] * (FLAC__int64)data[i-1];
residual[i] = data[i] - (sum >> lp_quantization);
}
}
else { /* order == 5 */
for(i = 0; i < (int)data_len; i++) {
sum = 0;
sum += qlp_coeff[4] * (FLAC__int64)data[i-5];
sum += qlp_coeff[3] * (FLAC__int64)data[i-4];
sum += qlp_coeff[2] * (FLAC__int64)data[i-3];
sum += qlp_coeff[1] * (FLAC__int64)data[i-2];
sum += qlp_coeff[0] * (FLAC__int64)data[i-1];
residual[i] = data[i] - (sum >> lp_quantization);
}
}
}
}
else {
if(order > 2) {
if(order == 4) {
for(i = 0; i < (int)data_len; i++) {
sum = 0;
sum += qlp_coeff[3] * (FLAC__int64)data[i-4];
sum += qlp_coeff[2] * (FLAC__int64)data[i-3];
sum += qlp_coeff[1] * (FLAC__int64)data[i-2];
sum += qlp_coeff[0] * (FLAC__int64)data[i-1];
residual[i] = data[i] - (sum >> lp_quantization);
}
}
else { /* order == 3 */
for(i = 0; i < (int)data_len; i++) {
sum = 0;
sum += qlp_coeff[2] * (FLAC__int64)data[i-3];
sum += qlp_coeff[1] * (FLAC__int64)data[i-2];
sum += qlp_coeff[0] * (FLAC__int64)data[i-1];
residual[i] = data[i] - (sum >> lp_quantization);
}
}
}
else {
if(order == 2) {
for(i = 0; i < (int)data_len; i++) {
sum = 0;
sum += qlp_coeff[1] * (FLAC__int64)data[i-2];
sum += qlp_coeff[0] * (FLAC__int64)data[i-1];
residual[i] = data[i] - (sum >> lp_quantization);
}
}
else { /* order == 1 */
for(i = 0; i < (int)data_len; i++)
residual[i] = data[i] - ((qlp_coeff[0] * (FLAC__int64)data[i-1]) >> lp_quantization);
}
}
}
}
else { /* order > 12 */
for(i = 0; i < (int)data_len; i++) {
sum = 0;
switch(order) {
case 32: sum += qlp_coeff[31] * (FLAC__int64)data[i-32]; /* Falls through. */
case 31: sum += qlp_coeff[30] * (FLAC__int64)data[i-31]; /* Falls through. */
case 30: sum += qlp_coeff[29] * (FLAC__int64)data[i-30]; /* Falls through. */
case 29: sum += qlp_coeff[28] * (FLAC__int64)data[i-29]; /* Falls through. */
case 28: sum += qlp_coeff[27] * (FLAC__int64)data[i-28]; /* Falls through. */
case 27: sum += qlp_coeff[26] * (FLAC__int64)data[i-27]; /* Falls through. */
case 26: sum += qlp_coeff[25] * (FLAC__int64)data[i-26]; /* Falls through. */
case 25: sum += qlp_coeff[24] * (FLAC__int64)data[i-25]; /* Falls through. */
case 24: sum += qlp_coeff[23] * (FLAC__int64)data[i-24]; /* Falls through. */
case 23: sum += qlp_coeff[22] * (FLAC__int64)data[i-23]; /* Falls through. */
case 22: sum += qlp_coeff[21] * (FLAC__int64)data[i-22]; /* Falls through. */
case 21: sum += qlp_coeff[20] * (FLAC__int64)data[i-21]; /* Falls through. */
case 20: sum += qlp_coeff[19] * (FLAC__int64)data[i-20]; /* Falls through. */
case 19: sum += qlp_coeff[18] * (FLAC__int64)data[i-19]; /* Falls through. */
case 18: sum += qlp_coeff[17] * (FLAC__int64)data[i-18]; /* Falls through. */
case 17: sum += qlp_coeff[16] * (FLAC__int64)data[i-17]; /* Falls through. */
case 16: sum += qlp_coeff[15] * (FLAC__int64)data[i-16]; /* Falls through. */
case 15: sum += qlp_coeff[14] * (FLAC__int64)data[i-15]; /* Falls through. */
case 14: sum += qlp_coeff[13] * (FLAC__int64)data[i-14]; /* Falls through. */
case 13: sum += qlp_coeff[12] * (FLAC__int64)data[i-13];
sum += qlp_coeff[11] * (FLAC__int64)data[i-12];
sum += qlp_coeff[10] * (FLAC__int64)data[i-11];
sum += qlp_coeff[ 9] * (FLAC__int64)data[i-10];
sum += qlp_coeff[ 8] * (FLAC__int64)data[i- 9];
sum += qlp_coeff[ 7] * (FLAC__int64)data[i- 8];
sum += qlp_coeff[ 6] * (FLAC__int64)data[i- 7];
sum += qlp_coeff[ 5] * (FLAC__int64)data[i- 6];
sum += qlp_coeff[ 4] * (FLAC__int64)data[i- 5];
sum += qlp_coeff[ 3] * (FLAC__int64)data[i- 4];
sum += qlp_coeff[ 2] * (FLAC__int64)data[i- 3];
sum += qlp_coeff[ 1] * (FLAC__int64)data[i- 2];
sum += qlp_coeff[ 0] * (FLAC__int64)data[i- 1];
}
residual[i] = data[i] - (sum >> lp_quantization);
}
}
}
#endif
FLAC__bool FLAC__lpc_compute_residual_from_qlp_coefficients_limit_residual(const FLAC__int32 * flac_restrict data, uint32_t data_len, const FLAC__int32 * flac_restrict qlp_coeff, uint32_t order, int lp_quantization, FLAC__int32 * flac_restrict residual)
{
int i;
FLAC__int64 sum, residual_to_check;
FLAC__ASSERT(order > 0);
FLAC__ASSERT(order <= 32);
for(i = 0; i < (int)data_len; i++) {
sum = 0;
switch(order) {
case 32: sum += qlp_coeff[31] * (FLAC__int64)data[i-32]; /* Falls through. */
case 31: sum += qlp_coeff[30] * (FLAC__int64)data[i-31]; /* Falls through. */
case 30: sum += qlp_coeff[29] * (FLAC__int64)data[i-30]; /* Falls through. */
case 29: sum += qlp_coeff[28] * (FLAC__int64)data[i-29]; /* Falls through. */
case 28: sum += qlp_coeff[27] * (FLAC__int64)data[i-28]; /* Falls through. */
case 27: sum += qlp_coeff[26] * (FLAC__int64)data[i-27]; /* Falls through. */
case 26: sum += qlp_coeff[25] * (FLAC__int64)data[i-26]; /* Falls through. */
case 25: sum += qlp_coeff[24] * (FLAC__int64)data[i-25]; /* Falls through. */
case 24: sum += qlp_coeff[23] * (FLAC__int64)data[i-24]; /* Falls through. */
case 23: sum += qlp_coeff[22] * (FLAC__int64)data[i-23]; /* Falls through. */
case 22: sum += qlp_coeff[21] * (FLAC__int64)data[i-22]; /* Falls through. */
case 21: sum += qlp_coeff[20] * (FLAC__int64)data[i-21]; /* Falls through. */
case 20: sum += qlp_coeff[19] * (FLAC__int64)data[i-20]; /* Falls through. */
case 19: sum += qlp_coeff[18] * (FLAC__int64)data[i-19]; /* Falls through. */
case 18: sum += qlp_coeff[17] * (FLAC__int64)data[i-18]; /* Falls through. */
case 17: sum += qlp_coeff[16] * (FLAC__int64)data[i-17]; /* Falls through. */
case 16: sum += qlp_coeff[15] * (FLAC__int64)data[i-16]; /* Falls through. */
case 15: sum += qlp_coeff[14] * (FLAC__int64)data[i-15]; /* Falls through. */
case 14: sum += qlp_coeff[13] * (FLAC__int64)data[i-14]; /* Falls through. */
case 13: sum += qlp_coeff[12] * (FLAC__int64)data[i-13]; /* Falls through. */
case 12: sum += qlp_coeff[11] * (FLAC__int64)data[i-12]; /* Falls through. */
case 11: sum += qlp_coeff[10] * (FLAC__int64)data[i-11]; /* Falls through. */
case 10: sum += qlp_coeff[ 9] * (FLAC__int64)data[i-10]; /* Falls through. */
case 9: sum += qlp_coeff[ 8] * (FLAC__int64)data[i- 9]; /* Falls through. */
case 8: sum += qlp_coeff[ 7] * (FLAC__int64)data[i- 8]; /* Falls through. */
case 7: sum += qlp_coeff[ 6] * (FLAC__int64)data[i- 7]; /* Falls through. */
case 6: sum += qlp_coeff[ 5] * (FLAC__int64)data[i- 6]; /* Falls through. */
case 5: sum += qlp_coeff[ 4] * (FLAC__int64)data[i- 5]; /* Falls through. */
case 4: sum += qlp_coeff[ 3] * (FLAC__int64)data[i- 4]; /* Falls through. */
case 3: sum += qlp_coeff[ 2] * (FLAC__int64)data[i- 3]; /* Falls through. */
case 2: sum += qlp_coeff[ 1] * (FLAC__int64)data[i- 2]; /* Falls through. */
case 1: sum += qlp_coeff[ 0] * (FLAC__int64)data[i- 1];
}
residual_to_check = data[i] - (sum >> lp_quantization);
/* residual must not be INT32_MIN because abs(INT32_MIN) is undefined */
if(residual_to_check <= INT32_MIN || residual_to_check > INT32_MAX)
return false;
else
residual[i] = residual_to_check;
}
return true;
}
FLAC__bool FLAC__lpc_compute_residual_from_qlp_coefficients_limit_residual_33bit(const FLAC__int64 * flac_restrict data, uint32_t data_len, const FLAC__int32 * flac_restrict qlp_coeff, uint32_t order, int lp_quantization, FLAC__int32 * flac_restrict residual)
{
int i;
FLAC__int64 sum, residual_to_check;
FLAC__ASSERT(order > 0);
FLAC__ASSERT(order <= 32);
for(i = 0; i < (int)data_len; i++) {
sum = 0;
switch(order) {
case 32: sum += qlp_coeff[31] * data[i-32]; /* Falls through. */
case 31: sum += qlp_coeff[30] * data[i-31]; /* Falls through. */
case 30: sum += qlp_coeff[29] * data[i-30]; /* Falls through. */
case 29: sum += qlp_coeff[28] * data[i-29]; /* Falls through. */
case 28: sum += qlp_coeff[27] * data[i-28]; /* Falls through. */
case 27: sum += qlp_coeff[26] * data[i-27]; /* Falls through. */
case 26: sum += qlp_coeff[25] * data[i-26]; /* Falls through. */
case 25: sum += qlp_coeff[24] * data[i-25]; /* Falls through. */
case 24: sum += qlp_coeff[23] * data[i-24]; /* Falls through. */
case 23: sum += qlp_coeff[22] * data[i-23]; /* Falls through. */
case 22: sum += qlp_coeff[21] * data[i-22]; /* Falls through. */
case 21: sum += qlp_coeff[20] * data[i-21]; /* Falls through. */
case 20: sum += qlp_coeff[19] * data[i-20]; /* Falls through. */
case 19: sum += qlp_coeff[18] * data[i-19]; /* Falls through. */
case 18: sum += qlp_coeff[17] * data[i-18]; /* Falls through. */
case 17: sum += qlp_coeff[16] * data[i-17]; /* Falls through. */
case 16: sum += qlp_coeff[15] * data[i-16]; /* Falls through. */
case 15: sum += qlp_coeff[14] * data[i-15]; /* Falls through. */
case 14: sum += qlp_coeff[13] * data[i-14]; /* Falls through. */
case 13: sum += qlp_coeff[12] * data[i-13]; /* Falls through. */
case 12: sum += qlp_coeff[11] * data[i-12]; /* Falls through. */
case 11: sum += qlp_coeff[10] * data[i-11]; /* Falls through. */
case 10: sum += qlp_coeff[ 9] * data[i-10]; /* Falls through. */
case 9: sum += qlp_coeff[ 8] * data[i- 9]; /* Falls through. */
case 8: sum += qlp_coeff[ 7] * data[i- 8]; /* Falls through. */
case 7: sum += qlp_coeff[ 6] * data[i- 7]; /* Falls through. */
case 6: sum += qlp_coeff[ 5] * data[i- 6]; /* Falls through. */
case 5: sum += qlp_coeff[ 4] * data[i- 5]; /* Falls through. */
case 4: sum += qlp_coeff[ 3] * data[i- 4]; /* Falls through. */
case 3: sum += qlp_coeff[ 2] * data[i- 3]; /* Falls through. */
case 2: sum += qlp_coeff[ 1] * data[i- 2]; /* Falls through. */
case 1: sum += qlp_coeff[ 0] * data[i- 1];
}
residual_to_check = data[i] - (sum >> lp_quantization);
/* residual must not be INT32_MIN because abs(INT32_MIN) is undefined */
if(residual_to_check <= INT32_MIN || residual_to_check > INT32_MAX)
return false;
else
residual[i] = residual_to_check;
}
return true;
}
#endif /* !defined FLAC__INTEGER_ONLY_LIBRARY */
uint32_t FLAC__lpc_max_prediction_before_shift_bps(uint32_t subframe_bps, const FLAC__int32 * flac_restrict qlp_coeff, uint32_t order)
{
/* This used to be subframe_bps + qlp_coeff_precision + FLAC__bitmath_ilog2(order)
* but that treats both the samples as well as the predictor as unknown. The
* predictor is known however, so taking the log2 of the sum of the absolute values
* of all coefficients is a more accurate representation of the predictor */
FLAC__int32 abs_sum_of_qlp_coeff = 0;
for(uint32_t i = 0; i < order; i++)
abs_sum_of_qlp_coeff += abs(qlp_coeff[i]);
if(abs_sum_of_qlp_coeff == 0)
abs_sum_of_qlp_coeff = 1;
return subframe_bps + FLAC__bitmath_silog2(abs_sum_of_qlp_coeff);
}
uint32_t FLAC__lpc_max_residual_bps(uint32_t subframe_bps, const FLAC__int32 * flac_restrict qlp_coeff, uint32_t order, int lp_quantization)
{
FLAC__int32 predictor_sum_bps = FLAC__lpc_max_prediction_before_shift_bps(subframe_bps, qlp_coeff, order) - lp_quantization;
if((int)subframe_bps > predictor_sum_bps)
return subframe_bps + 1;
else
return predictor_sum_bps + 1;
}
#ifdef FUZZING_BUILD_MODE_NO_SANITIZE_SIGNED_INTEGER_OVERFLOW
/* The attribute below is to silence the undefined sanitizer of oss-fuzz.
* Because fuzzing feeds bogus predictors and residual samples to the
* decoder, having overflows in this section is unavoidable. Also,
* because the calculated values are audio path only, there is no
* potential for security problems */
__attribute__((no_sanitize("signed-integer-overflow")))
#endif
void FLAC__lpc_restore_signal(const FLAC__int32 * flac_restrict residual, uint32_t data_len, const FLAC__int32 * flac_restrict qlp_coeff, uint32_t order, int lp_quantization, FLAC__int32 * flac_restrict data)
#if defined(FLAC__OVERFLOW_DETECT) || !defined(FLAC__LPC_UNROLLED_FILTER_LOOPS)
{
FLAC__int64 sumo;
uint32_t i, j;
FLAC__int32 sum;
const FLAC__int32 *r = residual, *history;
#ifdef FLAC__OVERFLOW_DETECT_VERBOSE
fprintf(stderr,"FLAC__lpc_restore_signal: data_len=%d, order=%u, lpq=%d",data_len,order,lp_quantization);
for(i=0;i<order;i++)
fprintf(stderr,", q[%u]=%d",i,qlp_coeff[i]);
fprintf(stderr,"\n");
#endif
FLAC__ASSERT(order > 0);
for(i = 0; i < data_len; i++) {
sumo = 0;
sum = 0;
history = data;
for(j = 0; j < order; j++) {
sum += qlp_coeff[j] * (*(--history));
sumo += (FLAC__int64)qlp_coeff[j] * (FLAC__int64)(*history);
#ifdef FLAC__OVERFLOW_DETECT
if(sumo > 2147483647ll || sumo < -2147483648ll)
fprintf(stderr,"FLAC__lpc_restore_signal: OVERFLOW, i=%u, j=%u, c=%d, d=%d, sumo=%" PRId64 "\n",i,j,qlp_coeff[j],*history,sumo);
#endif
}
*(data++) = *(r++) + (sum >> lp_quantization);
}
/* Here's a slower but clearer version:
for(i = 0; i < data_len; i++) {
sum = 0;
for(j = 0; j < order; j++)
sum += qlp_coeff[j] * data[i-j-1];
data[i] = residual[i] + (sum >> lp_quantization);
}
*/
}
#else /* fully unrolled version for normal use */
{
int i;
FLAC__int32 sum;
FLAC__ASSERT(order > 0);
FLAC__ASSERT(order <= 32);
/*
* We do unique versions up to 12th order since that's the subset limit.
* Also they are roughly ordered to match frequency of occurrence to
* minimize branching.
*/
if(order <= 12) {
if(order > 8) {
if(order > 10) {
if(order == 12) {
for(i = 0; i < (int)data_len; i++) {
sum = 0;
sum += qlp_coeff[11] * data[i-12];
sum += qlp_coeff[10] * data[i-11];
sum += qlp_coeff[9] * data[i-10];
sum += qlp_coeff[8] * data[i-9];
sum += qlp_coeff[7] * data[i-8];
sum += qlp_coeff[6] * data[i-7];
sum += qlp_coeff[5] * data[i-6];
sum += qlp_coeff[4] * data[i-5];
sum += qlp_coeff[3] * data[i-4];
sum += qlp_coeff[2] * data[i-3];
sum += qlp_coeff[1] * data[i-2];
sum += qlp_coeff[0] * data[i-1];
data[i] = residual[i] + (sum >> lp_quantization);
}
}
else { /* order == 11 */
for(i = 0; i < (int)data_len; i++) {
sum = 0;
sum += qlp_coeff[10] * data[i-11];
sum += qlp_coeff[9] * data[i-10];
sum += qlp_coeff[8] * data[i-9];
sum += qlp_coeff[7] * data[i-8];
sum += qlp_coeff[6] * data[i-7];
sum += qlp_coeff[5] * data[i-6];
sum += qlp_coeff[4] * data[i-5];
sum += qlp_coeff[3] * data[i-4];
sum += qlp_coeff[2] * data[i-3];
sum += qlp_coeff[1] * data[i-2];
sum += qlp_coeff[0] * data[i-1];
data[i] = residual[i] + (sum >> lp_quantization);
}
}
}
else {
if(order == 10) {
for(i = 0; i < (int)data_len; i++) {
sum = 0;
sum += qlp_coeff[9] * data[i-10];
sum += qlp_coeff[8] * data[i-9];
sum += qlp_coeff[7] * data[i-8];
sum += qlp_coeff[6] * data[i-7];
sum += qlp_coeff[5] * data[i-6];
sum += qlp_coeff[4] * data[i-5];
sum += qlp_coeff[3] * data[i-4];
sum += qlp_coeff[2] * data[i-3];
sum += qlp_coeff[1] * data[i-2];
sum += qlp_coeff[0] * data[i-1];
data[i] = residual[i] + (sum >> lp_quantization);
}
}
else { /* order == 9 */
for(i = 0; i < (int)data_len; i++) {
sum = 0;
sum += qlp_coeff[8] * data[i-9];
sum += qlp_coeff[7] * data[i-8];
sum += qlp_coeff[6] * data[i-7];
sum += qlp_coeff[5] * data[i-6];
sum += qlp_coeff[4] * data[i-5];
sum += qlp_coeff[3] * data[i-4];
sum += qlp_coeff[2] * data[i-3];
sum += qlp_coeff[1] * data[i-2];
sum += qlp_coeff[0] * data[i-1];
data[i] = residual[i] + (sum >> lp_quantization);
}
}
}
}
else if(order > 4) {
if(order > 6) {
if(order == 8) {
for(i = 0; i < (int)data_len; i++) {
sum = 0;
sum += qlp_coeff[7] * data[i-8];
sum += qlp_coeff[6] * data[i-7];
sum += qlp_coeff[5] * data[i-6];
sum += qlp_coeff[4] * data[i-5];
sum += qlp_coeff[3] * data[i-4];
sum += qlp_coeff[2] * data[i-3];
sum += qlp_coeff[1] * data[i-2];
sum += qlp_coeff[0] * data[i-1];
data[i] = residual[i] + (sum >> lp_quantization);
}
}
else { /* order == 7 */
for(i = 0; i < (int)data_len; i++) {
sum = 0;
sum += qlp_coeff[6] * data[i-7];
sum += qlp_coeff[5] * data[i-6];
sum += qlp_coeff[4] * data[i-5];
sum += qlp_coeff[3] * data[i-4];
sum += qlp_coeff[2] * data[i-3];
sum += qlp_coeff[1] * data[i-2];
sum += qlp_coeff[0] * data[i-1];
data[i] = residual[i] + (sum >> lp_quantization);
}
}
}
else {
if(order == 6) {
for(i = 0; i < (int)data_len; i++) {
sum = 0;
sum += qlp_coeff[5] * data[i-6];
sum += qlp_coeff[4] * data[i-5];
sum += qlp_coeff[3] * data[i-4];
sum += qlp_coeff[2] * data[i-3];
sum += qlp_coeff[1] * data[i-2];
sum += qlp_coeff[0] * data[i-1];
data[i] = residual[i] + (sum >> lp_quantization);
}
}
else { /* order == 5 */
for(i = 0; i < (int)data_len; i++) {
sum = 0;
sum += qlp_coeff[4] * data[i-5];
sum += qlp_coeff[3] * data[i-4];
sum += qlp_coeff[2] * data[i-3];
sum += qlp_coeff[1] * data[i-2];
sum += qlp_coeff[0] * data[i-1];
data[i] = residual[i] + (sum >> lp_quantization);
}
}
}
}
else {
if(order > 2) {
if(order == 4) {
for(i = 0; i < (int)data_len; i++) {
sum = 0;
sum += qlp_coeff[3] * data[i-4];
sum += qlp_coeff[2] * data[i-3];
sum += qlp_coeff[1] * data[i-2];
sum += qlp_coeff[0] * data[i-1];
data[i] = residual[i] + (sum >> lp_quantization);
}
}
else { /* order == 3 */
for(i = 0; i < (int)data_len; i++) {
sum = 0;
sum += qlp_coeff[2] * data[i-3];
sum += qlp_coeff[1] * data[i-2];
sum += qlp_coeff[0] * data[i-1];
data[i] = residual[i] + (sum >> lp_quantization);
}
}
}
else {
if(order == 2) {
for(i = 0; i < (int)data_len; i++) {
sum = 0;
sum += qlp_coeff[1] * data[i-2];
sum += qlp_coeff[0] * data[i-1];
data[i] = residual[i] + (sum >> lp_quantization);
}
}
else { /* order == 1 */
for(i = 0; i < (int)data_len; i++)
data[i] = residual[i] + ((qlp_coeff[0] * data[i-1]) >> lp_quantization);
}
}
}
}
else { /* order > 12 */
for(i = 0; i < (int)data_len; i++) {
sum = 0;
switch(order) {
case 32: sum += qlp_coeff[31] * data[i-32]; /* Falls through. */
case 31: sum += qlp_coeff[30] * data[i-31]; /* Falls through. */
case 30: sum += qlp_coeff[29] * data[i-30]; /* Falls through. */
case 29: sum += qlp_coeff[28] * data[i-29]; /* Falls through. */
case 28: sum += qlp_coeff[27] * data[i-28]; /* Falls through. */
case 27: sum += qlp_coeff[26] * data[i-27]; /* Falls through. */
case 26: sum += qlp_coeff[25] * data[i-26]; /* Falls through. */
case 25: sum += qlp_coeff[24] * data[i-25]; /* Falls through. */
case 24: sum += qlp_coeff[23] * data[i-24]; /* Falls through. */
case 23: sum += qlp_coeff[22] * data[i-23]; /* Falls through. */
case 22: sum += qlp_coeff[21] * data[i-22]; /* Falls through. */
case 21: sum += qlp_coeff[20] * data[i-21]; /* Falls through. */
case 20: sum += qlp_coeff[19] * data[i-20]; /* Falls through. */
case 19: sum += qlp_coeff[18] * data[i-19]; /* Falls through. */
case 18: sum += qlp_coeff[17] * data[i-18]; /* Falls through. */
case 17: sum += qlp_coeff[16] * data[i-17]; /* Falls through. */
case 16: sum += qlp_coeff[15] * data[i-16]; /* Falls through. */
case 15: sum += qlp_coeff[14] * data[i-15]; /* Falls through. */
case 14: sum += qlp_coeff[13] * data[i-14]; /* Falls through. */
case 13: sum += qlp_coeff[12] * data[i-13];
sum += qlp_coeff[11] * data[i-12];
sum += qlp_coeff[10] * data[i-11];
sum += qlp_coeff[ 9] * data[i-10];
sum += qlp_coeff[ 8] * data[i- 9];
sum += qlp_coeff[ 7] * data[i- 8];
sum += qlp_coeff[ 6] * data[i- 7];
sum += qlp_coeff[ 5] * data[i- 6];
sum += qlp_coeff[ 4] * data[i- 5];
sum += qlp_coeff[ 3] * data[i- 4];
sum += qlp_coeff[ 2] * data[i- 3];
sum += qlp_coeff[ 1] * data[i- 2];
sum += qlp_coeff[ 0] * data[i- 1];
}
data[i] = residual[i] + (sum >> lp_quantization);
}
}
}
#endif
void FLAC__lpc_restore_signal_wide(const FLAC__int32 * flac_restrict residual, uint32_t data_len, const FLAC__int32 * flac_restrict qlp_coeff, uint32_t order, int lp_quantization, FLAC__int32 * flac_restrict data)
#if defined(FLAC__OVERFLOW_DETECT) || !defined(FLAC__LPC_UNROLLED_FILTER_LOOPS)
{
uint32_t i, j;
FLAC__int64 sum;
const FLAC__int32 *r = residual, *history;
#ifdef FLAC__OVERFLOW_DETECT_VERBOSE
fprintf(stderr,"FLAC__lpc_restore_signal_wide: data_len=%d, order=%u, lpq=%d",data_len,order,lp_quantization);
for(i=0;i<order;i++)
fprintf(stderr,", q[%u]=%d",i,qlp_coeff[i]);
fprintf(stderr,"\n");
#endif
FLAC__ASSERT(order > 0);
for(i = 0; i < data_len; i++) {
sum = 0;
history = data;
for(j = 0; j < order; j++)
sum += (FLAC__int64)qlp_coeff[j] * (FLAC__int64)(*(--history));
#ifdef FLAC__OVERFLOW_DETECT
if(FLAC__bitmath_silog2((FLAC__int64)(*r) + (sum >> lp_quantization)) > 32) {
fprintf(stderr,"FLAC__lpc_restore_signal_wide: OVERFLOW, i=%u, residual=%d, sum=%" PRId64 ", data=%" PRId64 "\n", i, *r, (sum >> lp_quantization), ((FLAC__int64)(*r) + (sum >> lp_quantization)));
break;
}
#endif
*(data++) = (FLAC__int32)(*(r++) + (sum >> lp_quantization));
}
}
#else /* fully unrolled version for normal use */
{
int i;
FLAC__int64 sum;
FLAC__ASSERT(order > 0);
FLAC__ASSERT(order <= 32);
/*
* We do unique versions up to 12th order since that's the subset limit.
* Also they are roughly ordered to match frequency of occurrence to
* minimize branching.
*/
if(order <= 12) {
if(order > 8) {
if(order > 10) {
if(order == 12) {
for(i = 0; i < (int)data_len; i++) {
sum = 0;
sum += qlp_coeff[11] * (FLAC__int64)data[i-12];
sum += qlp_coeff[10] * (FLAC__int64)data[i-11];
sum += qlp_coeff[9] * (FLAC__int64)data[i-10];
sum += qlp_coeff[8] * (FLAC__int64)data[i-9];
sum += qlp_coeff[7] * (FLAC__int64)data[i-8];
sum += qlp_coeff[6] * (FLAC__int64)data[i-7];
sum += qlp_coeff[5] * (FLAC__int64)data[i-6];
sum += qlp_coeff[4] * (FLAC__int64)data[i-5];
sum += qlp_coeff[3] * (FLAC__int64)data[i-4];
sum += qlp_coeff[2] * (FLAC__int64)data[i-3];
sum += qlp_coeff[1] * (FLAC__int64)data[i-2];
sum += qlp_coeff[0] * (FLAC__int64)data[i-1];
data[i] = (FLAC__int32) (residual[i] + (sum >> lp_quantization));
}
}
else { /* order == 11 */
for(i = 0; i < (int)data_len; i++) {
sum = 0;
sum += qlp_coeff[10] * (FLAC__int64)data[i-11];
sum += qlp_coeff[9] * (FLAC__int64)data[i-10];
sum += qlp_coeff[8] * (FLAC__int64)data[i-9];
sum += qlp_coeff[7] * (FLAC__int64)data[i-8];
sum += qlp_coeff[6] * (FLAC__int64)data[i-7];
sum += qlp_coeff[5] * (FLAC__int64)data[i-6];
sum += qlp_coeff[4] * (FLAC__int64)data[i-5];
sum += qlp_coeff[3] * (FLAC__int64)data[i-4];
sum += qlp_coeff[2] * (FLAC__int64)data[i-3];
sum += qlp_coeff[1] * (FLAC__int64)data[i-2];
sum += qlp_coeff[0] * (FLAC__int64)data[i-1];
data[i] = (FLAC__int32) (residual[i] + (sum >> lp_quantization));
}
}
}
else {
if(order == 10) {
for(i = 0; i < (int)data_len; i++) {
sum = 0;
sum += qlp_coeff[9] * (FLAC__int64)data[i-10];
sum += qlp_coeff[8] * (FLAC__int64)data[i-9];
sum += qlp_coeff[7] * (FLAC__int64)data[i-8];
sum += qlp_coeff[6] * (FLAC__int64)data[i-7];
sum += qlp_coeff[5] * (FLAC__int64)data[i-6];
sum += qlp_coeff[4] * (FLAC__int64)data[i-5];
sum += qlp_coeff[3] * (FLAC__int64)data[i-4];
sum += qlp_coeff[2] * (FLAC__int64)data[i-3];
sum += qlp_coeff[1] * (FLAC__int64)data[i-2];
sum += qlp_coeff[0] * (FLAC__int64)data[i-1];
data[i] = (FLAC__int32) (residual[i] + (sum >> lp_quantization));
}
}
else { /* order == 9 */
for(i = 0; i < (int)data_len; i++) {
sum = 0;
sum += qlp_coeff[8] * (FLAC__int64)data[i-9];
sum += qlp_coeff[7] * (FLAC__int64)data[i-8];
sum += qlp_coeff[6] * (FLAC__int64)data[i-7];
sum += qlp_coeff[5] * (FLAC__int64)data[i-6];
sum += qlp_coeff[4] * (FLAC__int64)data[i-5];
sum += qlp_coeff[3] * (FLAC__int64)data[i-4];
sum += qlp_coeff[2] * (FLAC__int64)data[i-3];
sum += qlp_coeff[1] * (FLAC__int64)data[i-2];
sum += qlp_coeff[0] * (FLAC__int64)data[i-1];
data[i] = (FLAC__int32) (residual[i] + (sum >> lp_quantization));
}
}
}
}
else if(order > 4) {
if(order > 6) {
if(order == 8) {
for(i = 0; i < (int)data_len; i++) {
sum = 0;
sum += qlp_coeff[7] * (FLAC__int64)data[i-8];
sum += qlp_coeff[6] * (FLAC__int64)data[i-7];
sum += qlp_coeff[5] * (FLAC__int64)data[i-6];
sum += qlp_coeff[4] * (FLAC__int64)data[i-5];
sum += qlp_coeff[3] * (FLAC__int64)data[i-4];
sum += qlp_coeff[2] * (FLAC__int64)data[i-3];
sum += qlp_coeff[1] * (FLAC__int64)data[i-2];
sum += qlp_coeff[0] * (FLAC__int64)data[i-1];
data[i] = (FLAC__int32) (residual[i] + (sum >> lp_quantization));
}
}
else { /* order == 7 */
for(i = 0; i < (int)data_len; i++) {
sum = 0;
sum += qlp_coeff[6] * (FLAC__int64)data[i-7];
sum += qlp_coeff[5] * (FLAC__int64)data[i-6];
sum += qlp_coeff[4] * (FLAC__int64)data[i-5];
sum += qlp_coeff[3] * (FLAC__int64)data[i-4];
sum += qlp_coeff[2] * (FLAC__int64)data[i-3];
sum += qlp_coeff[1] * (FLAC__int64)data[i-2];
sum += qlp_coeff[0] * (FLAC__int64)data[i-1];
data[i] = (FLAC__int32) (residual[i] + (sum >> lp_quantization));
}
}
}
else {
if(order == 6) {
for(i = 0; i < (int)data_len; i++) {
sum = 0;
sum += qlp_coeff[5] * (FLAC__int64)data[i-6];
sum += qlp_coeff[4] * (FLAC__int64)data[i-5];
sum += qlp_coeff[3] * (FLAC__int64)data[i-4];
sum += qlp_coeff[2] * (FLAC__int64)data[i-3];
sum += qlp_coeff[1] * (FLAC__int64)data[i-2];
sum += qlp_coeff[0] * (FLAC__int64)data[i-1];
data[i] = (FLAC__int32) (residual[i] + (sum >> lp_quantization));
}
}
else { /* order == 5 */
for(i = 0; i < (int)data_len; i++) {
sum = 0;
sum += qlp_coeff[4] * (FLAC__int64)data[i-5];
sum += qlp_coeff[3] * (FLAC__int64)data[i-4];
sum += qlp_coeff[2] * (FLAC__int64)data[i-3];
sum += qlp_coeff[1] * (FLAC__int64)data[i-2];
sum += qlp_coeff[0] * (FLAC__int64)data[i-1];
data[i] = (FLAC__int32) (residual[i] + (sum >> lp_quantization));
}
}
}
}
else {
if(order > 2) {
if(order == 4) {
for(i = 0; i < (int)data_len; i++) {
sum = 0;
sum += qlp_coeff[3] * (FLAC__int64)data[i-4];
sum += qlp_coeff[2] * (FLAC__int64)data[i-3];
sum += qlp_coeff[1] * (FLAC__int64)data[i-2];
sum += qlp_coeff[0] * (FLAC__int64)data[i-1];
data[i] = (FLAC__int32) (residual[i] + (sum >> lp_quantization));
}
}
else { /* order == 3 */
for(i = 0; i < (int)data_len; i++) {
sum = 0;
sum += qlp_coeff[2] * (FLAC__int64)data[i-3];
sum += qlp_coeff[1] * (FLAC__int64)data[i-2];
sum += qlp_coeff[0] * (FLAC__int64)data[i-1];
data[i] = (FLAC__int32) (residual[i] + (sum >> lp_quantization));
}
}
}
else {
if(order == 2) {
for(i = 0; i < (int)data_len; i++) {
sum = 0;
sum += qlp_coeff[1] * (FLAC__int64)data[i-2];
sum += qlp_coeff[0] * (FLAC__int64)data[i-1];
data[i] = (FLAC__int32) (residual[i] + (sum >> lp_quantization));
}
}
else { /* order == 1 */
for(i = 0; i < (int)data_len; i++)
data[i] = (FLAC__int32)(residual[i] + ((qlp_coeff[0] * (FLAC__int64)data[i-1]) >> lp_quantization));
}
}
}
}
else { /* order > 12 */
for(i = 0; i < (int)data_len; i++) {
sum = 0;
switch(order) {
case 32: sum += qlp_coeff[31] * (FLAC__int64)data[i-32]; /* Falls through. */
case 31: sum += qlp_coeff[30] * (FLAC__int64)data[i-31]; /* Falls through. */
case 30: sum += qlp_coeff[29] * (FLAC__int64)data[i-30]; /* Falls through. */
case 29: sum += qlp_coeff[28] * (FLAC__int64)data[i-29]; /* Falls through. */
case 28: sum += qlp_coeff[27] * (FLAC__int64)data[i-28]; /* Falls through. */
case 27: sum += qlp_coeff[26] * (FLAC__int64)data[i-27]; /* Falls through. */
case 26: sum += qlp_coeff[25] * (FLAC__int64)data[i-26]; /* Falls through. */
case 25: sum += qlp_coeff[24] * (FLAC__int64)data[i-25]; /* Falls through. */
case 24: sum += qlp_coeff[23] * (FLAC__int64)data[i-24]; /* Falls through. */
case 23: sum += qlp_coeff[22] * (FLAC__int64)data[i-23]; /* Falls through. */
case 22: sum += qlp_coeff[21] * (FLAC__int64)data[i-22]; /* Falls through. */
case 21: sum += qlp_coeff[20] * (FLAC__int64)data[i-21]; /* Falls through. */
case 20: sum += qlp_coeff[19] * (FLAC__int64)data[i-20]; /* Falls through. */
case 19: sum += qlp_coeff[18] * (FLAC__int64)data[i-19]; /* Falls through. */
case 18: sum += qlp_coeff[17] * (FLAC__int64)data[i-18]; /* Falls through. */
case 17: sum += qlp_coeff[16] * (FLAC__int64)data[i-17]; /* Falls through. */
case 16: sum += qlp_coeff[15] * (FLAC__int64)data[i-16]; /* Falls through. */
case 15: sum += qlp_coeff[14] * (FLAC__int64)data[i-15]; /* Falls through. */
case 14: sum += qlp_coeff[13] * (FLAC__int64)data[i-14]; /* Falls through. */
case 13: sum += qlp_coeff[12] * (FLAC__int64)data[i-13];
sum += qlp_coeff[11] * (FLAC__int64)data[i-12];
sum += qlp_coeff[10] * (FLAC__int64)data[i-11];
sum += qlp_coeff[ 9] * (FLAC__int64)data[i-10];
sum += qlp_coeff[ 8] * (FLAC__int64)data[i- 9];
sum += qlp_coeff[ 7] * (FLAC__int64)data[i- 8];
sum += qlp_coeff[ 6] * (FLAC__int64)data[i- 7];
sum += qlp_coeff[ 5] * (FLAC__int64)data[i- 6];
sum += qlp_coeff[ 4] * (FLAC__int64)data[i- 5];
sum += qlp_coeff[ 3] * (FLAC__int64)data[i- 4];
sum += qlp_coeff[ 2] * (FLAC__int64)data[i- 3];
sum += qlp_coeff[ 1] * (FLAC__int64)data[i- 2];
sum += qlp_coeff[ 0] * (FLAC__int64)data[i- 1];
}
data[i] = (FLAC__int32) (residual[i] + (sum >> lp_quantization));
}
}
}
#endif
#ifdef FUZZING_BUILD_MODE_NO_SANITIZE_SIGNED_INTEGER_OVERFLOW
/* The attribute below is to silence the undefined sanitizer of oss-fuzz.
* Because fuzzing feeds bogus predictors and residual samples to the
* decoder, having overflows in this section is unavoidable. Also,
* because the calculated values are audio path only, there is no
* potential for security problems */
__attribute__((no_sanitize("signed-integer-overflow")))
#endif
void FLAC__lpc_restore_signal_wide_33bit(const FLAC__int32 * flac_restrict residual, uint32_t data_len, const FLAC__int32 * flac_restrict qlp_coeff, uint32_t order, int lp_quantization, FLAC__int64 * flac_restrict data)
#if defined(FLAC__OVERFLOW_DETECT) || !defined(FLAC__LPC_UNROLLED_FILTER_LOOPS)
{
uint32_t i, j;
FLAC__int64 sum;
const FLAC__int32 *r = residual;
const FLAC__int64 *history;
FLAC__ASSERT(order > 0);
for(i = 0; i < data_len; i++) {
sum = 0;
history = data;
for(j = 0; j < order; j++)
sum += (FLAC__int64)qlp_coeff[j] * (FLAC__int64)(*(--history));
#ifdef FLAC__OVERFLOW_DETECT
if(FLAC__bitmath_silog2((FLAC__int64)(*r) + (sum >> lp_quantization)) > 33) {
fprintf(stderr,"FLAC__lpc_restore_signal_33bit: OVERFLOW, i=%u, residual=%d, sum=%" PRId64 ", data=%" PRId64 "\n", i, *r, (sum >> lp_quantization), ((FLAC__int64)(*r) + (sum >> lp_quantization)));
break;
}
#endif
*(data++) = (FLAC__int64)(*(r++)) + (sum >> lp_quantization);
}
}
#else /* unrolled version for normal use */
{
int i;
FLAC__int64 sum;
FLAC__ASSERT(order > 0);
FLAC__ASSERT(order <= 32);
for(i = 0; i < (int)data_len; i++) {
sum = 0;
switch(order) {
case 32: sum += qlp_coeff[31] * data[i-32]; /* Falls through. */
case 31: sum += qlp_coeff[30] * data[i-31]; /* Falls through. */
case 30: sum += qlp_coeff[29] * data[i-30]; /* Falls through. */
case 29: sum += qlp_coeff[28] * data[i-29]; /* Falls through. */
case 28: sum += qlp_coeff[27] * data[i-28]; /* Falls through. */
case 27: sum += qlp_coeff[26] * data[i-27]; /* Falls through. */
case 26: sum += qlp_coeff[25] * data[i-26]; /* Falls through. */
case 25: sum += qlp_coeff[24] * data[i-25]; /* Falls through. */
case 24: sum += qlp_coeff[23] * data[i-24]; /* Falls through. */
case 23: sum += qlp_coeff[22] * data[i-23]; /* Falls through. */
case 22: sum += qlp_coeff[21] * data[i-22]; /* Falls through. */
case 21: sum += qlp_coeff[20] * data[i-21]; /* Falls through. */
case 20: sum += qlp_coeff[19] * data[i-20]; /* Falls through. */
case 19: sum += qlp_coeff[18] * data[i-19]; /* Falls through. */
case 18: sum += qlp_coeff[17] * data[i-18]; /* Falls through. */
case 17: sum += qlp_coeff[16] * data[i-17]; /* Falls through. */
case 16: sum += qlp_coeff[15] * data[i-16]; /* Falls through. */
case 15: sum += qlp_coeff[14] * data[i-15]; /* Falls through. */
case 14: sum += qlp_coeff[13] * data[i-14]; /* Falls through. */
case 13: sum += qlp_coeff[12] * data[i-13]; /* Falls through. */
case 12: sum += qlp_coeff[11] * data[i-12]; /* Falls through. */
case 11: sum += qlp_coeff[10] * data[i-11]; /* Falls through. */
case 10: sum += qlp_coeff[ 9] * data[i-10]; /* Falls through. */
case 9: sum += qlp_coeff[ 8] * data[i- 9]; /* Falls through. */
case 8: sum += qlp_coeff[ 7] * data[i- 8]; /* Falls through. */
case 7: sum += qlp_coeff[ 6] * data[i- 7]; /* Falls through. */
case 6: sum += qlp_coeff[ 5] * data[i- 6]; /* Falls through. */
case 5: sum += qlp_coeff[ 4] * data[i- 5]; /* Falls through. */
case 4: sum += qlp_coeff[ 3] * data[i- 4]; /* Falls through. */
case 3: sum += qlp_coeff[ 2] * data[i- 3]; /* Falls through. */
case 2: sum += qlp_coeff[ 1] * data[i- 2]; /* Falls through. */
case 1: sum += qlp_coeff[ 0] * data[i- 1];
}
data[i] = residual[i] + (sum >> lp_quantization);
}
}
#endif
#if defined(_MSC_VER)
#pragma warning ( default : 4028 )
#endif
#ifndef FLAC__INTEGER_ONLY_LIBRARY
double FLAC__lpc_compute_expected_bits_per_residual_sample(double lpc_error, uint32_t total_samples)
{
double error_scale;
FLAC__ASSERT(total_samples > 0);
error_scale = 0.5 / (double)total_samples;
return FLAC__lpc_compute_expected_bits_per_residual_sample_with_error_scale(lpc_error, error_scale);
}
double FLAC__lpc_compute_expected_bits_per_residual_sample_with_error_scale(double lpc_error, double error_scale)
{
if(lpc_error > 0.0) {
double bps = (double)0.5 * log(error_scale * lpc_error) / M_LN2;
if(bps >= 0.0)
return bps;
else
return 0.0;
}
else if(lpc_error < 0.0) { /* error should not be negative but can happen due to inadequate floating-point resolution */
return 1e32;
}
else {
return 0.0;
}
}
uint32_t FLAC__lpc_compute_best_order(const double lpc_error[], uint32_t max_order, uint32_t total_samples, uint32_t overhead_bits_per_order)
{
uint32_t order, indx, best_index; /* 'index' the index into lpc_error; index==order-1 since lpc_error[0] is for order==1, lpc_error[1] is for order==2, etc */
double bits, best_bits, error_scale;
FLAC__ASSERT(max_order > 0);
FLAC__ASSERT(total_samples > 0);
error_scale = 0.5 / (double)total_samples;
best_index = 0;
best_bits = (uint32_t)(-1);
for(indx = 0, order = 1; indx < max_order; indx++, order++) {
bits = FLAC__lpc_compute_expected_bits_per_residual_sample_with_error_scale(lpc_error[indx], error_scale) * (double)(total_samples - order) + (double)(order * overhead_bits_per_order);
if(bits < best_bits) {
best_index = indx;
best_bits = bits;
}
}
return best_index+1; /* +1 since indx of lpc_error[] is order-1 */
}
#endif /* !defined FLAC__INTEGER_ONLY_LIBRARY */