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_MyCorr.c 16 17 ******************************************************************/ 18 19 #include "defines.h" 20 21 /*----------------------------------------------------------------* 22 * compute cross correlation between sequences 23 *---------------------------------------------------------------*/ 24 25 void WebRtcIlbcfix_MyCorr( 26 int32_t *corr, /* (o) correlation of seq1 and seq2 */ 27 int16_t *seq1, /* (i) first sequence */ 28 int16_t dim1, /* (i) dimension first seq1 */ 29 const int16_t *seq2, /* (i) second sequence */ 30 int16_t dim2 /* (i) dimension seq2 */ 31 ){ 32 int16_t max, scale, loops; 33 34 /* Calculate correlation between the two sequences. Scale the 35 result of the multiplcication to maximum 26 bits in order 36 to avoid overflow */ 37 max=WebRtcSpl_MaxAbsValueW16(seq1, dim1); 38 scale=WebRtcSpl_GetSizeInBits(max); 39 40 scale = (int16_t)(WEBRTC_SPL_MUL_16_16(2,scale)-26); 41 if (scale<0) { 42 scale=0; 43 } 44 45 loops=dim1-dim2+1; 46 47 /* Calculate the cross correlations */ 48 WebRtcSpl_CrossCorrelation(corr, (int16_t*)seq2, seq1, dim2, loops, scale, 1); 49 50 return; 51 } 52
