| /* |
| * 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 */ |
| size_t lag, /* (i) pitch lag */ |
| size_t bLen, /* (i) length of buffer */ |
| size_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; |
| } |
| } |