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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_SimpleLsfDeQ.c
******************************************************************/
#include "modules/audio_coding/codecs/ilbc/simple_lsf_dequant.h"
#include "modules/audio_coding/codecs/ilbc/constants.h"
#include "modules/audio_coding/codecs/ilbc/defines.h"
/*----------------------------------------------------------------*
* obtain dequantized lsf coefficients from quantization index
*---------------------------------------------------------------*/
void WebRtcIlbcfix_SimpleLsfDeQ(
int16_t *lsfdeq, /* (o) dequantized lsf coefficients */
int16_t *index, /* (i) quantization index */
int16_t lpc_n /* (i) number of LPCs */
){
int i, j, pos, cb_pos;
/* decode first LSF */
pos = 0;
cb_pos = 0;
for (i = 0; i < LSF_NSPLIT; i++) {
for (j = 0; j < WebRtcIlbcfix_kLsfDimCb[i]; j++) {
lsfdeq[pos + j] = WebRtcIlbcfix_kLsfCb[cb_pos + j + index[i] *
WebRtcIlbcfix_kLsfDimCb[i]];
}
pos += WebRtcIlbcfix_kLsfDimCb[i];
cb_pos += WebRtcIlbcfix_kLsfSizeCb[i] * WebRtcIlbcfix_kLsfDimCb[i];
}
if (lpc_n>1) {
/* decode last LSF */
pos = 0;
cb_pos = 0;
for (i = 0; i < LSF_NSPLIT; i++) {
for (j = 0; j < WebRtcIlbcfix_kLsfDimCb[i]; j++) {
lsfdeq[LPC_FILTERORDER + pos + j] = WebRtcIlbcfix_kLsfCb[
cb_pos + index[LSF_NSPLIT + i] * WebRtcIlbcfix_kLsfDimCb[i] + j];
}
pos += WebRtcIlbcfix_kLsfDimCb[i];
cb_pos += WebRtcIlbcfix_kLsfSizeCb[i] * WebRtcIlbcfix_kLsfDimCb[i];
}
}
return;
}
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