1 /*
2 * Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
3 *
4 * Use of this source code is governed by a BSD-style license
5 * that can be found in the LICENSE file in the root of the source
6 * tree. An additional intellectual property rights grant can be found
7 * in the file PATENTS. All contributing project authors may
8 * be found in the AUTHORS file in the root of the source tree.
9 */
10
11 /******************************************************************
12
13 iLBC Speech Coder ANSI-C Source Code
14
15 WebRtcIlbcfix_CompCorr.c
16
17 ******************************************************************/
18
19 #include "modules/audio_coding/codecs/ilbc/comp_corr.h"
20
21 #include "modules/audio_coding/codecs/ilbc/defines.h"
22
23 /*----------------------------------------------------------------*
24 * Compute cross correlation and pitch gain for pitch prediction
25 * of last subframe at given lag.
26 *---------------------------------------------------------------*/
27
WebRtcIlbcfix_CompCorr(int32_t * corr,int32_t * ener,int16_t * buffer,size_t lag,size_t bLen,size_t sRange,int16_t scale)28 void WebRtcIlbcfix_CompCorr(
29 int32_t *corr, /* (o) cross correlation */
30 int32_t *ener, /* (o) energy */
31 int16_t *buffer, /* (i) signal buffer */
32 size_t lag, /* (i) pitch lag */
33 size_t bLen, /* (i) length of buffer */
34 size_t sRange, /* (i) correlation search length */
35 int16_t scale /* (i) number of rightshifts to use */
36 ){
37 int16_t *w16ptr;
38
39 w16ptr=&buffer[bLen-sRange-lag];
40
41 /* Calculate correlation and energy */
42 (*corr)=WebRtcSpl_DotProductWithScale(&buffer[bLen-sRange], w16ptr, sRange, scale);
43 (*ener)=WebRtcSpl_DotProductWithScale(w16ptr, w16ptr, sRange, scale);
44
45 /* For zero energy set the energy to 0 in order to avoid potential
46 problems for coming divisions */
47 if (*ener == 0) {
48 *corr = 0;
49 *ener = 1;
50 }
51 }
52