* LPC utility code
* Copyright (c) 2006 Justin Ruggles <justin.ruggles@gmail.com>
*
- * This file is part of FFmpeg.
+ * This file is part of Libav.
*
- * FFmpeg is free software; you can redistribute it and/or
+ * Libav is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
- * FFmpeg is distributed in the hope that it will be useful,
+ * Libav 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
- * License along with FFmpeg; if not, write to the Free Software
+ * License along with Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "libavutil/lls.h"
-#include "dsputil.h"
#define LPC_USE_DOUBLE
#include "lpc.h"
/**
* Apply Welch window function to audio block
*/
-static void apply_welch_window(const int32_t *data, int len, double *w_data)
+static void lpc_apply_welch_window_c(const int32_t *data, int len,
+ double *w_data)
{
int i, n2;
double w;
double c;
- assert(!(len&1)); //the optimization in r11881 does not support odd len
- //if someone wants odd len extend the change in r11881
+ /* The optimization in commit fa4ed8c does not support odd len.
+ * If someone wants odd len extend that change. */
+ assert(!(len & 1));
n2 = (len >> 1);
c = 2.0 / (len - 1.0);
* Calculate autocorrelation data from audio samples
* A Welch window function is applied before calculation.
*/
-void ff_lpc_compute_autocorr(const int32_t *data, int len, int lag,
- double *autoc)
+static void lpc_compute_autocorr_c(const double *data, int len, int lag,
+ double *autoc)
{
int i, j;
- double tmp[len + lag + 1];
- double *data1= tmp + lag;
-
- apply_welch_window(data, len, data1);
-
- for(j=0; j<lag; j++)
- data1[j-lag]= 0.0;
- data1[len] = 0.0;
for(j=0; j<lag; j+=2){
double sum0 = 1.0, sum1 = 1.0;
for(i=j; i<len; i++){
- sum0 += data1[i] * data1[i-j];
- sum1 += data1[i] * data1[i-j-1];
+ sum0 += data[i] * data[i-j];
+ sum1 += data[i] * data[i-j-1];
}
autoc[j ] = sum0;
autoc[j+1] = sum1;
if(j==lag){
double sum = 1.0;
for(i=j-1; i<len; i+=2){
- sum += data1[i ] * data1[i-j ]
- + data1[i+1] * data1[i-j+1];
+ sum += data[i ] * data[i-j ]
+ + data[i+1] * data[i-j+1];
}
autoc[j] = sum;
}
/**
* Calculate LPC coefficients for multiple orders
*
- * @param use_lpc LPC method for determining coefficients
- * 0 = LPC with fixed pre-defined coeffs
- * 1 = LPC with coeffs determined by Levinson-Durbin recursion
- * 2+ = LPC with coeffs determined by Cholesky factorization using (use_lpc-1) passes.
+ * @param lpc_type LPC method for determining coefficients,
+ * see #FFLPCType for details
*/
-int ff_lpc_calc_coefs(DSPContext *s,
+int ff_lpc_calc_coefs(LPCContext *s,
const int32_t *samples, int blocksize, int min_order,
int max_order, int precision,
int32_t coefs[][MAX_LPC_ORDER], int *shift,
- enum AVLPCType lpc_type, int lpc_passes,
+ enum FFLPCType lpc_type, int lpc_passes,
int omethod, int max_shift, int zero_shift)
{
double autoc[MAX_LPC_ORDER+1];
int opt_order;
assert(max_order >= MIN_LPC_ORDER && max_order <= MAX_LPC_ORDER &&
- lpc_type > AV_LPC_TYPE_FIXED);
+ lpc_type > FF_LPC_TYPE_FIXED);
+
+ /* reinit LPC context if parameters have changed */
+ if (blocksize != s->blocksize || max_order != s->max_order ||
+ lpc_type != s->lpc_type) {
+ ff_lpc_end(s);
+ ff_lpc_init(s, blocksize, max_order, lpc_type);
+ }
+
+ if (lpc_type == FF_LPC_TYPE_LEVINSON) {
+ double *windowed_samples = s->windowed_samples + max_order;
- if (lpc_type == AV_LPC_TYPE_LEVINSON) {
- s->lpc_compute_autocorr(samples, blocksize, max_order, autoc);
+ s->lpc_apply_welch_window(samples, blocksize, windowed_samples);
+
+ s->lpc_compute_autocorr(windowed_samples, blocksize, max_order, autoc);
compute_lpc_coefs(autoc, max_order, &lpc[0][0], MAX_LPC_ORDER, 0, 1);
for(i=0; i<max_order; i++)
ref[i] = fabs(lpc[i][i]);
- } else if (lpc_type == AV_LPC_TYPE_CHOLESKY) {
+ } else if (lpc_type == FF_LPC_TYPE_CHOLESKY) {
LLSModel m[2];
double var[MAX_LPC_ORDER+1], av_uninit(weight);
return opt_order;
}
+
+av_cold int ff_lpc_init(LPCContext *s, int blocksize, int max_order,
+ enum FFLPCType lpc_type)
+{
+ s->blocksize = blocksize;
+ s->max_order = max_order;
+ s->lpc_type = lpc_type;
+
+ if (lpc_type == FF_LPC_TYPE_LEVINSON) {
+ s->windowed_samples = av_mallocz((blocksize + max_order + 2) *
+ sizeof(*s->windowed_samples));
+ if (!s->windowed_samples)
+ return AVERROR(ENOMEM);
+ } else {
+ s->windowed_samples = NULL;
+ }
+
+ s->lpc_apply_welch_window = lpc_apply_welch_window_c;
+ s->lpc_compute_autocorr = lpc_compute_autocorr_c;
+
+ if (HAVE_MMX)
+ ff_lpc_init_x86(s);
+
+ return 0;
+}
+
+av_cold void ff_lpc_end(LPCContext *s)
+{
+ av_freep(&s->windowed_samples);
+}
projects / ffmpeg / blobdiff