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/*
* Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
/******************************************************************
iLBC Speech Coder ANSI-C Source Code
WebRtcIlbcfix_CompCorr.c
******************************************************************/
#include "defines.h"
/*----------------------------------------------------------------*
* Compute cross correlation and pitch gain for pitch prediction
* of last subframe at given lag.
*---------------------------------------------------------------*/
void WebRtcIlbcfix_CompCorr(
int32_t *corr, /* (o) cross correlation */
int32_t *ener, /* (o) energy */
int16_t *buffer, /* (i) signal buffer */
int16_t lag, /* (i) pitch lag */
int16_t bLen, /* (i) length of buffer */
int16_t sRange, /* (i) correlation search length */
int16_t scale /* (i) number of rightshifts to use */
){
int16_t *w16ptr;
w16ptr=&buffer[bLen-sRange-lag];
/* Calculate correlation and energy */
(*corr)=WebRtcSpl_DotProductWithScale(&buffer[bLen-sRange], w16ptr, sRange, scale);
(*ener)=WebRtcSpl_DotProductWithScale(w16ptr, w16ptr, sRange, scale);
/* For zero energy set the energy to 0 in order to avoid potential
problems for coming divisions */
if (*ener == 0) {
*corr = 0;
*ener = 1;
}
}
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