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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_StateConstruct.c
******************************************************************/
#include "modules/audio_coding/codecs/ilbc/state_construct.h"
#include "modules/audio_coding/codecs/ilbc/constants.h"
#include "modules/audio_coding/codecs/ilbc/defines.h"
/*----------------------------------------------------------------*
* decoding of the start state
*---------------------------------------------------------------*/
void WebRtcIlbcfix_StateConstruct(
size_t idxForMax, /* (i) 6-bit index for the quantization of
max amplitude */
int16_t *idxVec, /* (i) vector of quantization indexes */
int16_t *syntDenum, /* (i) synthesis filter denumerator */
int16_t *Out_fix, /* (o) the decoded state vector */
size_t len /* (i) length of a state vector */
) {
size_t k;
int16_t maxVal;
int16_t *tmp1, *tmp2, *tmp3;
/* Stack based */
int16_t numerator[1+LPC_FILTERORDER];
int16_t sampleValVec[2*STATE_SHORT_LEN_30MS+LPC_FILTERORDER];
int16_t sampleMaVec[2*STATE_SHORT_LEN_30MS+LPC_FILTERORDER];
int16_t *sampleVal = &sampleValVec[LPC_FILTERORDER];
int16_t *sampleMa = &sampleMaVec[LPC_FILTERORDER];
int16_t *sampleAr = &sampleValVec[LPC_FILTERORDER];
/* initialization of coefficients */
for (k=0; k<LPC_FILTERORDER+1; k++){
numerator[k] = syntDenum[LPC_FILTERORDER-k];
}
/* decoding of the maximum value */
maxVal = WebRtcIlbcfix_kFrgQuantMod[idxForMax];
/* decoding of the sample values */
tmp1 = sampleVal;
tmp2 = &idxVec[len-1];
if (idxForMax<37) {
for(k=0; k<len; k++){
/*the shifting is due to the Q13 in sq4_fixQ13[i], also the adding of 2097152 (= 0.5 << 22)
maxVal is in Q8 and result is in Q(-1) */
*tmp1 = (int16_t)((maxVal * WebRtcIlbcfix_kStateSq3[*tmp2] + 2097152) >>
22);
tmp1++;
tmp2--;
}
} else if (idxForMax<59) {
for(k=0; k<len; k++){
/*the shifting is due to the Q13 in sq4_fixQ13[i], also the adding of 262144 (= 0.5 << 19)
maxVal is in Q5 and result is in Q(-1) */
*tmp1 = (int16_t)((maxVal * WebRtcIlbcfix_kStateSq3[*tmp2] + 262144) >>
19);
tmp1++;
tmp2--;
}
} else {
for(k=0; k<len; k++){
/*the shifting is due to the Q13 in sq4_fixQ13[i], also the adding of 65536 (= 0.5 << 17)
maxVal is in Q3 and result is in Q(-1) */
*tmp1 = (int16_t)((maxVal * WebRtcIlbcfix_kStateSq3[*tmp2] + 65536) >>
17);
tmp1++;
tmp2--;
}
}
/* Set the rest of the data to zero */
WebRtcSpl_MemSetW16(&sampleVal[len], 0, len);
/* circular convolution with all-pass filter */
/* Set the state to zero */
WebRtcSpl_MemSetW16(sampleValVec, 0, (LPC_FILTERORDER));
/* Run MA filter + AR filter */
WebRtcSpl_FilterMAFastQ12(
sampleVal, sampleMa,
numerator, LPC_FILTERORDER+1, len + LPC_FILTERORDER);
WebRtcSpl_MemSetW16(&sampleMa[len + LPC_FILTERORDER], 0, (len - LPC_FILTERORDER));
WebRtcSpl_FilterARFastQ12(
sampleMa, sampleAr,
syntDenum, LPC_FILTERORDER+1, 2 * len);
tmp1 = &sampleAr[len-1];
tmp2 = &sampleAr[2*len-1];
tmp3 = Out_fix;
for(k=0;k<len;k++){
(*tmp3) = (*tmp1) + (*tmp2);
tmp1--;
tmp2--;
tmp3++;
}
}
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