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 "defines.h" 20 21 /*----------------------------------------------------------------* 22 * Compute cross correlation and pitch gain for pitch prediction 23 * of last subframe at given lag. 24 *---------------------------------------------------------------*/ 25 26 void WebRtcIlbcfix_CompCorr( 27 int32_t *corr, /* (o) cross correlation */ 28 int32_t *ener, /* (o) energy */ 29 int16_t *buffer, /* (i) signal buffer */ 30 int16_t lag, /* (i) pitch lag */ 31 int16_t bLen, /* (i) length of buffer */ 32 int16_t sRange, /* (i) correlation search length */ 33 int16_t scale /* (i) number of rightshifts to use */ 34 ){ 35 int16_t *w16ptr; 36 37 w16ptr=&buffer[bLen-sRange-lag]; 38 39 /* Calculate correlation and energy */ 40 (*corr)=WebRtcSpl_DotProductWithScale(&buffer[bLen-sRange], w16ptr, sRange, scale); 41 (*ener)=WebRtcSpl_DotProductWithScale(w16ptr, w16ptr, sRange, scale); 42 43 /* For zero energy set the energy to 0 in order to avoid potential 44 problems for coming divisions */ 45 if (*ener == 0) { 46 *corr = 0; 47 *ener = 1; 48 } 49 } 50
