mirror of
https://github.com/mollyim/webrtc.git
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62 lines
2.1 KiB
C
62 lines
2.1 KiB
C
/*
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* Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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/******************************************************************
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iLBC Speech Coder ANSI-C Source Code
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WebRtcIlbcfix_SimpleLsfDeQ.c
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******************************************************************/
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#include "modules/audio_coding/codecs/ilbc/simple_lsf_dequant.h"
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#include "modules/audio_coding/codecs/ilbc/constants.h"
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#include "modules/audio_coding/codecs/ilbc/defines.h"
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/*----------------------------------------------------------------*
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* obtain dequantized lsf coefficients from quantization index
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*---------------------------------------------------------------*/
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void WebRtcIlbcfix_SimpleLsfDeQ(
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int16_t *lsfdeq, /* (o) dequantized lsf coefficients */
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int16_t *index, /* (i) quantization index */
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int16_t lpc_n /* (i) number of LPCs */
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){
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int i, j, pos, cb_pos;
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/* decode first LSF */
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pos = 0;
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cb_pos = 0;
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for (i = 0; i < LSF_NSPLIT; i++) {
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for (j = 0; j < WebRtcIlbcfix_kLsfDimCb[i]; j++) {
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lsfdeq[pos + j] = WebRtcIlbcfix_kLsfCb[cb_pos + j + index[i] *
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WebRtcIlbcfix_kLsfDimCb[i]];
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}
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pos += WebRtcIlbcfix_kLsfDimCb[i];
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cb_pos += WebRtcIlbcfix_kLsfSizeCb[i] * WebRtcIlbcfix_kLsfDimCb[i];
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}
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if (lpc_n>1) {
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/* decode last LSF */
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pos = 0;
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cb_pos = 0;
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for (i = 0; i < LSF_NSPLIT; i++) {
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for (j = 0; j < WebRtcIlbcfix_kLsfDimCb[i]; j++) {
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lsfdeq[LPC_FILTERORDER + pos + j] = WebRtcIlbcfix_kLsfCb[
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cb_pos + index[LSF_NSPLIT + i] * WebRtcIlbcfix_kLsfDimCb[i] + j];
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}
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pos += WebRtcIlbcfix_kLsfDimCb[i];
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cb_pos += WebRtcIlbcfix_kLsfSizeCb[i] * WebRtcIlbcfix_kLsfDimCb[i];
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}
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}
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return;
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}
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