112 lines
3.8 KiB
C
112 lines
3.8 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_StateConstruct.c
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******************************************************************/
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#include "defines.h"
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#include "constants.h"
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/*----------------------------------------------------------------*
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* decoding of the start state
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*---------------------------------------------------------------*/
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void WebRtcIlbcfix_StateConstruct(
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WebRtc_Word16 idxForMax, /* (i) 6-bit index for the quantization of
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max amplitude */
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WebRtc_Word16 *idxVec, /* (i) vector of quantization indexes */
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WebRtc_Word16 *syntDenum, /* (i) synthesis filter denumerator */
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WebRtc_Word16 *Out_fix, /* (o) the decoded state vector */
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WebRtc_Word16 len /* (i) length of a state vector */
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) {
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int k;
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WebRtc_Word16 maxVal;
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WebRtc_Word16 *tmp1, *tmp2, *tmp3;
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/* Stack based */
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WebRtc_Word16 numerator[1+LPC_FILTERORDER];
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WebRtc_Word16 sampleValVec[2*STATE_SHORT_LEN_30MS+LPC_FILTERORDER];
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WebRtc_Word16 sampleMaVec[2*STATE_SHORT_LEN_30MS+LPC_FILTERORDER];
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WebRtc_Word16 *sampleVal = &sampleValVec[LPC_FILTERORDER];
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WebRtc_Word16 *sampleMa = &sampleMaVec[LPC_FILTERORDER];
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WebRtc_Word16 *sampleAr = &sampleValVec[LPC_FILTERORDER];
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/* initialization of coefficients */
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for (k=0; k<LPC_FILTERORDER+1; k++){
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numerator[k] = syntDenum[LPC_FILTERORDER-k];
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}
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/* decoding of the maximum value */
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maxVal = WebRtcIlbcfix_kFrgQuantMod[idxForMax];
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/* decoding of the sample values */
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tmp1 = sampleVal;
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tmp2 = &idxVec[len-1];
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if (idxForMax<37) {
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for(k=0; k<len; k++){
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/*the shifting is due to the Q13 in sq4_fixQ13[i], also the adding of 2097152 (= 0.5 << 22)
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maxVal is in Q8 and result is in Q(-1) */
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(*tmp1) = (WebRtc_Word16) ((WEBRTC_SPL_MUL_16_16(maxVal,WebRtcIlbcfix_kStateSq3[(*tmp2)])+(WebRtc_Word32)2097152) >> 22);
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tmp1++;
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tmp2--;
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}
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} else if (idxForMax<59) {
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for(k=0; k<len; k++){
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/*the shifting is due to the Q13 in sq4_fixQ13[i], also the adding of 262144 (= 0.5 << 19)
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maxVal is in Q5 and result is in Q(-1) */
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(*tmp1) = (WebRtc_Word16) ((WEBRTC_SPL_MUL_16_16(maxVal,WebRtcIlbcfix_kStateSq3[(*tmp2)])+(WebRtc_Word32)262144) >> 19);
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tmp1++;
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tmp2--;
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}
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} else {
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for(k=0; k<len; k++){
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/*the shifting is due to the Q13 in sq4_fixQ13[i], also the adding of 65536 (= 0.5 << 17)
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maxVal is in Q3 and result is in Q(-1) */
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(*tmp1) = (WebRtc_Word16) ((WEBRTC_SPL_MUL_16_16(maxVal,WebRtcIlbcfix_kStateSq3[(*tmp2)])+(WebRtc_Word32)65536) >> 17);
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tmp1++;
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tmp2--;
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}
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}
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/* Set the rest of the data to zero */
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WebRtcSpl_MemSetW16(&sampleVal[len], 0, len);
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/* circular convolution with all-pass filter */
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/* Set the state to zero */
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WebRtcSpl_MemSetW16(sampleValVec, 0, (LPC_FILTERORDER));
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/* Run MA filter + AR filter */
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WebRtcSpl_FilterMAFastQ12(
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sampleVal, sampleMa,
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numerator, LPC_FILTERORDER+1, (WebRtc_Word16)(len + LPC_FILTERORDER));
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WebRtcSpl_MemSetW16(&sampleMa[len + LPC_FILTERORDER], 0, (len - LPC_FILTERORDER));
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WebRtcSpl_FilterARFastQ12(
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sampleMa, sampleAr,
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syntDenum, LPC_FILTERORDER+1, (WebRtc_Word16)(2*len));
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tmp1 = &sampleAr[len-1];
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tmp2 = &sampleAr[2*len-1];
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tmp3 = Out_fix;
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for(k=0;k<len;k++){
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(*tmp3) = (*tmp1) + (*tmp2);
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tmp1--;
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tmp2--;
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tmp3++;
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}
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}
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