/* libFLAC - Free Lossless Audio Codec library
- * Copyright (C) 2000,2001 Josh Coalson
+ * Copyright (C) 2000,2001,2002,2003 Josh Coalson
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
*/
#include <math.h>
-#include <stdio.h>
#include "FLAC/assert.h"
#include "FLAC/format.h"
+#include "private/bitmath.h"
#include "private/lpc.h"
+#if defined DEBUG || defined FLAC__OVERFLOW_DETECT || defined FLAC__OVERFLOW_DETECT_VERBOSE
+#include <stdio.h>
+#endif
#ifndef M_LN2
/* math.h in VC++ doesn't seem to have this (how Microsoft is that?) */
#define M_LN2 0.69314718055994530942
#endif
-#define LOCAL_FABS(x) ((x)<0.0? -(x):(x))
-
-void FLAC__lpc_compute_autocorrelation(const real data[], unsigned data_len, unsigned lag, real autoc[])
+void FLAC__lpc_compute_autocorrelation(const FLAC__real data[], unsigned data_len, unsigned lag, FLAC__real autoc[])
{
/* a readable, but slower, version */
#if 0
- real d;
+ FLAC__real d;
unsigned i;
FLAC__ASSERT(lag > 0);
* this version tends to run faster because of better data locality
* ('data_len' is usually much larger than 'lag')
*/
- real d;
+ FLAC__real d;
unsigned sample, coeff;
const unsigned limit = data_len - lag;
}
}
-void FLAC__lpc_compute_lp_coefficients(const real autoc[], unsigned max_order, real lp_coeff[][FLAC__MAX_LPC_ORDER], real error[])
+void FLAC__lpc_compute_lp_coefficients(const FLAC__real autoc[], unsigned max_order, FLAC__real lp_coeff[][FLAC__MAX_LPC_ORDER], FLAC__real error[])
{
unsigned i, j;
- real r, err, ref[FLAC__MAX_LPC_ORDER], lpc[FLAC__MAX_LPC_ORDER];
+ double r, err, ref[FLAC__MAX_LPC_ORDER], lpc[FLAC__MAX_LPC_ORDER];
FLAC__ASSERT(0 < max_order);
FLAC__ASSERT(max_order <= FLAC__MAX_LPC_ORDER);
/* Update LPC coefficients and total error. */
lpc[i]=r;
for(j = 0; j < (i>>1); j++) {
- real tmp = lpc[j];
+ double tmp = lpc[j];
lpc[j] += r * lpc[i-1-j];
lpc[i-1-j] += r * tmp;
}
/* save this order */
for(j = 0; j <= i; j++)
- lp_coeff[i][j] = -lpc[j]; /* negate FIR filter coeff to get predictor coeff */
- error[i] = err;
+ lp_coeff[i][j] = (FLAC__real)(-lpc[j]); /* negate FIR filter coeff to get predictor coeff */
+ error[i] = (FLAC__real)err;
}
}
-int FLAC__lpc_quantize_coefficients(const real lp_coeff[], unsigned order, unsigned precision, unsigned bits_per_sample, int32 qlp_coeff[], int *shift)
+int FLAC__lpc_quantize_coefficients(const FLAC__real lp_coeff[], unsigned order, unsigned precision, FLAC__int32 qlp_coeff[], int *shift)
{
unsigned i;
- real d, cmax = -1e32;
+ double d, cmax = -1e32;
+ FLAC__int32 qmax, qmin;
+ const int max_shiftlimit = (1 << (FLAC__SUBFRAME_LPC_QLP_SHIFT_LEN-1)) - 1;
+ const int min_shiftlimit = -max_shiftlimit - 1;
- FLAC__ASSERT(bits_per_sample > 0);
- FLAC__ASSERT(bits_per_sample <= sizeof(int32)*8);
FLAC__ASSERT(precision > 0);
FLAC__ASSERT(precision >= FLAC__MIN_QLP_COEFF_PRECISION);
- FLAC__ASSERT(precision + bits_per_sample < sizeof(int32)*8);
-#ifdef NDEBUG
- (void)bits_per_sample; /* silence compiler warning about unused parameter */
-#endif
/* drop one bit for the sign; from here on out we consider only |lp_coeff[i]| */
precision--;
+ qmax = 1 << precision;
+ qmin = -qmax;
+ qmax--;
for(i = 0; i < order; i++) {
if(lp_coeff[i] == 0.0)
continue;
- d = LOCAL_FABS(lp_coeff[i]);
+ d = fabs(lp_coeff[i]);
if(d > cmax)
cmax = d;
}
- if(cmax < 0.0) {
+redo_it:
+ if(cmax <= 0.0) {
/* => coefficients are all 0, which means our constant-detect didn't work */
return 2;
}
else {
- const int maxshift = (int)precision - (int)floor(log(cmax) / M_LN2) - 1;
- const int max_shiftlimit = (1 << (FLAC__SUBFRAME_LPC_QLP_SHIFT_LEN-1)) - 1;
- const int min_shiftlimit = -max_shiftlimit - 1;
+ int log2cmax;
- *shift = maxshift;
+ (void)frexp(cmax, &log2cmax);
+ log2cmax--;
+ *shift = (int)precision - log2cmax - 1;
if(*shift < min_shiftlimit || *shift > max_shiftlimit) {
- return 1;
+#if 0
+ /*@@@ this does not seem to help at all, but was not extensively tested either: */
+ if(*shift > max_shiftlimit)
+ *shift = max_shiftlimit;
+ else
+#endif
+ return 1;
}
}
- if(*shift != 0) { /* just to avoid wasting time... */
- for(i = 0; i < order; i++)
- qlp_coeff[i] = (int32)floor(lp_coeff[i] * (real)(1 << *shift));
+ if(*shift >= 0) {
+ for(i = 0; i < order; i++) {
+ qlp_coeff[i] = (FLAC__int32)floor((double)lp_coeff[i] * (double)(1 << *shift));
+
+ /* double-check the result */
+ if(qlp_coeff[i] > qmax || qlp_coeff[i] < qmin) {
+#ifdef FLAC__OVERFLOW_DETECT
+ fprintf(stderr,"FLAC__lpc_quantize_coefficients: compensating for overflow, qlp_coeff[%u]=%d, lp_coeff[%u]=%f, cmax=%f, precision=%u, shift=%d, q=%f, f(q)=%f\n", i, qlp_coeff[i], i, lp_coeff[i], cmax, precision, *shift, (double)lp_coeff[i] * (double)(1 << *shift), floor((double)lp_coeff[i] * (double)(1 << *shift)));
+#endif
+ cmax *= 2.0;
+ goto redo_it;
+ }
+ }
+ }
+ else { /* (*shift < 0) */
+ const int nshift = -(*shift);
+#ifdef DEBUG
+ fprintf(stderr,"FLAC__lpc_quantize_coefficients: negative shift = %d\n", *shift);
+#endif
+ for(i = 0; i < order; i++) {
+ qlp_coeff[i] = (FLAC__int32)floor((double)lp_coeff[i] / (double)(1 << nshift));
+
+ /* double-check the result */
+ if(qlp_coeff[i] > qmax || qlp_coeff[i] < qmin) {
+#ifdef FLAC__OVERFLOW_DETECT
+ fprintf(stderr,"FLAC__lpc_quantize_coefficients: compensating for overflow, qlp_coeff[%u]=%d, lp_coeff[%u]=%f, cmax=%f, precision=%u, shift=%d, q=%f, f(q)=%f\n", i, qlp_coeff[i], i, lp_coeff[i], cmax, precision, *shift, (double)lp_coeff[i] / (double)(1 << nshift), floor((double)lp_coeff[i] / (double)(1 << nshift)));
+#endif
+ cmax *= 2.0;
+ goto redo_it;
+ }
+ }
}
+
return 0;
}
-void FLAC__lpc_compute_residual_from_qlp_coefficients(const int32 data[], unsigned data_len, const int32 qlp_coeff[], unsigned order, int lp_quantization, int32 residual[])
+void FLAC__lpc_compute_residual_from_qlp_coefficients(const FLAC__int32 data[], unsigned data_len, const FLAC__int32 qlp_coeff[], unsigned order, int lp_quantization, FLAC__int32 residual[])
{
#ifdef FLAC__OVERFLOW_DETECT
- int64 sumo;
+ FLAC__int64 sumo;
#endif
unsigned i, j;
- int32 sum;
- const int32 *history;
+ 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(j = 0; j < order; j++) {
sum += qlp_coeff[j] * (*(--history));
#ifdef FLAC__OVERFLOW_DETECT
- sumo += (int64)qlp_coeff[j] * (int64)(*history);
- if(sumo > 2147483647ll || sumo < -2147483648ll) {
+ sumo += (FLAC__int64)qlp_coeff[j] * (FLAC__int64)(*history);
+#if defined _MSC_VER
+ if(sumo > 2147483647I64 || sumo < -2147483648I64)
+#else
+ if(sumo > 2147483647ll || sumo < -2147483648ll)
+#endif
+ {
fprintf(stderr,"FLAC__lpc_compute_residual_from_qlp_coefficients: OVERFLOW, i=%u, j=%u, c=%d, d=%d, sumo=%lld\n",i,j,qlp_coeff[j],*history,sumo);
}
#endif
*/
}
-void FLAC__lpc_restore_signal(const int32 residual[], unsigned data_len, const int32 qlp_coeff[], unsigned order, int lp_quantization, int32 data[])
+void FLAC__lpc_compute_residual_from_qlp_coefficients_wide(const FLAC__int32 data[], unsigned data_len, const FLAC__int32 qlp_coeff[], unsigned order, int lp_quantization, FLAC__int32 residual[])
{
+ unsigned 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));
#ifdef FLAC__OVERFLOW_DETECT
- int64 sumo;
+ if(FLAC__bitmath_silog2_wide(sum >> lp_quantization) > 32) {
+ fprintf(stderr,"FLAC__lpc_compute_residual_from_qlp_coefficients_wide: OVERFLOW, i=%u, sum=%lld\n", i, sum >> lp_quantization);
+ break;
+ }
+ if(FLAC__bitmath_silog2_wide((FLAC__int64)(*data) - (sum >> lp_quantization)) > 32) {
+ fprintf(stderr,"FLAC__lpc_compute_residual_from_qlp_coefficients_wide: OVERFLOW, i=%u, data=%d, sum=%lld, residual=%lld\n", i, *data, sum >> lp_quantization, (FLAC__int64)(*data) - (sum >> lp_quantization));
+ break;
+ }
+#endif
+ *(residual++) = *(data++) - (FLAC__int32)(sum >> lp_quantization);
+ }
+}
+
+void FLAC__lpc_restore_signal(const FLAC__int32 residual[], unsigned data_len, const FLAC__int32 qlp_coeff[], unsigned order, int lp_quantization, FLAC__int32 data[])
+{
+#ifdef FLAC__OVERFLOW_DETECT
+ FLAC__int64 sumo;
#endif
unsigned i, j;
- int32 sum;
- const int32 *history;
+ FLAC__int32 sum;
+ const FLAC__int32 *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(j = 0; j < order; j++) {
sum += qlp_coeff[j] * (*(--history));
#ifdef FLAC__OVERFLOW_DETECT
- sumo += (int64)qlp_coeff[j] * (int64)(*history);
- if(sumo > 2147483647ll || sumo < -2147483648ll) {
+ sumo += (FLAC__int64)qlp_coeff[j] * (FLAC__int64)(*history);
+#if defined _MSC_VER
+ if(sumo > 2147483647I64 || sumo < -2147483648I64)
+#else
+ if(sumo > 2147483647ll || sumo < -2147483648ll)
+#endif
+ {
fprintf(stderr,"FLAC__lpc_restore_signal: OVERFLOW, i=%u, j=%u, c=%d, d=%d, sumo=%lld\n",i,j,qlp_coeff[j],*history,sumo);
}
#endif
*/
}
-real FLAC__lpc_compute_expected_bits_per_residual_sample(real lpc_error, unsigned total_samples)
+void FLAC__lpc_restore_signal_wide(const FLAC__int32 residual[], unsigned data_len, const FLAC__int32 qlp_coeff[], unsigned order, int lp_quantization, FLAC__int32 data[])
{
- real error_scale;
+ unsigned i, j;
+ FLAC__int64 sum;
+ const FLAC__int32 *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_wide(sum >> lp_quantization) > 32) {
+ fprintf(stderr,"FLAC__lpc_restore_signal_wide: OVERFLOW, i=%u, sum=%lld\n", i, sum >> lp_quantization);
+ break;
+ }
+ if(FLAC__bitmath_silog2_wide((FLAC__int64)(*residual) + (sum >> lp_quantization)) > 32) {
+ fprintf(stderr,"FLAC__lpc_restore_signal_wide: OVERFLOW, i=%u, residual=%d, sum=%lld, data=%lld\n", i, *residual, sum >> lp_quantization, (FLAC__int64)(*residual) + (sum >> lp_quantization));
+ break;
+ }
+#endif
+ *(data++) = *(residual++) + (FLAC__int32)(sum >> lp_quantization);
+ }
+}
+
+FLAC__real FLAC__lpc_compute_expected_bits_per_residual_sample(FLAC__real lpc_error, unsigned total_samples)
+{
+ double error_scale;
FLAC__ASSERT(total_samples > 0);
- error_scale = 0.5 * M_LN2 * M_LN2 / (real)total_samples;
+ error_scale = 0.5 * M_LN2 * M_LN2 / (FLAC__real)total_samples;
- if(lpc_error > 0.0) {
- real bps = 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 float resolution */
- return 1e32;
- }
- else {
- return 0.0;
- }
+ return FLAC__lpc_compute_expected_bits_per_residual_sample_with_error_scale(lpc_error, error_scale);
}
-real FLAC__lpc_compute_expected_bits_per_residual_sample_with_error_scale(real lpc_error, real error_scale)
+FLAC__real FLAC__lpc_compute_expected_bits_per_residual_sample_with_error_scale(FLAC__real lpc_error, double error_scale)
{
if(lpc_error > 0.0) {
- real bps = 0.5 * log(error_scale * lpc_error) / M_LN2;
+ FLAC__real bps = (FLAC__real)((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 float resolution */
- return 1e32;
+ return (FLAC__real)1e32;
}
else {
return 0.0;
}
}
-unsigned FLAC__lpc_compute_best_order(const real lpc_error[], unsigned max_order, unsigned total_samples, unsigned bits_per_signal_sample)
+unsigned FLAC__lpc_compute_best_order(const FLAC__real lpc_error[], unsigned max_order, unsigned total_samples, unsigned bits_per_signal_sample)
{
unsigned order, best_order;
- real best_bits, tmp_bits, error_scale;
+ FLAC__real best_bits, tmp_bits;
+ double error_scale;
FLAC__ASSERT(max_order > 0);
FLAC__ASSERT(total_samples > 0);
- error_scale = 0.5 * M_LN2 * M_LN2 / (real)total_samples;
+ error_scale = 0.5 * M_LN2 * M_LN2 / (FLAC__real)total_samples;
best_order = 0;
- best_bits = FLAC__lpc_compute_expected_bits_per_residual_sample_with_error_scale(lpc_error[0], error_scale) * (real)total_samples;
+ best_bits = FLAC__lpc_compute_expected_bits_per_residual_sample_with_error_scale(lpc_error[0], error_scale) * (FLAC__real)total_samples;
for(order = 1; order < max_order; order++) {
- tmp_bits = FLAC__lpc_compute_expected_bits_per_residual_sample_with_error_scale(lpc_error[order], error_scale) * (real)(total_samples - order) + (real)(order * bits_per_signal_sample);
+ tmp_bits = FLAC__lpc_compute_expected_bits_per_residual_sample_with_error_scale(lpc_error[order], error_scale) * (FLAC__real)(total_samples - order) + (FLAC__real)(order * bits_per_signal_sample);
if(tmp_bits < best_bits) {
best_order = order;
best_bits = tmp_bits;
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