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120 lines
4.1 KiB
C
120 lines
4.1 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_StateSearch.c
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******************************************************************/
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#include "defines.h"
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#include "constants.h"
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#include "abs_quant.h"
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/*----------------------------------------------------------------*
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* encoding of start state
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*---------------------------------------------------------------*/
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void WebRtcIlbcfix_StateSearch(
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iLBC_Enc_Inst_t *iLBCenc_inst,
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/* (i) Encoder instance */
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iLBC_bits *iLBC_encbits,/* (i/o) Encoded bits (output idxForMax
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and idxVec, input state_first) */
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int16_t *residual, /* (i) target residual vector */
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int16_t *syntDenum, /* (i) lpc synthesis filter */
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int16_t *weightDenum /* (i) weighting filter denuminator */
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) {
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int16_t k, index;
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int16_t maxVal;
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int16_t scale, shift;
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int32_t maxValsq;
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int16_t scaleRes;
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int16_t max;
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int i;
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/* Stack based */
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int16_t numerator[1+LPC_FILTERORDER];
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int16_t residualLongVec[2*STATE_SHORT_LEN_30MS+LPC_FILTERORDER];
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int16_t sampleMa[2*STATE_SHORT_LEN_30MS];
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int16_t *residualLong = &residualLongVec[LPC_FILTERORDER];
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int16_t *sampleAr = residualLong;
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/* Scale to maximum 12 bits to avoid saturation in circular convolution filter */
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max = WebRtcSpl_MaxAbsValueW16(residual, iLBCenc_inst->state_short_len);
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scaleRes = WebRtcSpl_GetSizeInBits(max)-12;
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scaleRes = WEBRTC_SPL_MAX(0, scaleRes);
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/* Set up the filter coefficients for the circular convolution */
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for (i=0; i<LPC_FILTERORDER+1; i++) {
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numerator[i] = (syntDenum[LPC_FILTERORDER-i]>>scaleRes);
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}
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/* Copy the residual to a temporary buffer that we can filter
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* and set the remaining samples to zero.
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*/
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WEBRTC_SPL_MEMCPY_W16(residualLong, residual, iLBCenc_inst->state_short_len);
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WebRtcSpl_MemSetW16(residualLong + iLBCenc_inst->state_short_len, 0, iLBCenc_inst->state_short_len);
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/* Run the Zero-Pole filter (Ciurcular convolution) */
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WebRtcSpl_MemSetW16(residualLongVec, 0, LPC_FILTERORDER);
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WebRtcSpl_FilterMAFastQ12(
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residualLong, sampleMa,
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numerator, LPC_FILTERORDER+1, (int16_t)(iLBCenc_inst->state_short_len + LPC_FILTERORDER));
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WebRtcSpl_MemSetW16(&sampleMa[iLBCenc_inst->state_short_len + LPC_FILTERORDER], 0, iLBCenc_inst->state_short_len - LPC_FILTERORDER);
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WebRtcSpl_FilterARFastQ12(
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sampleMa, sampleAr,
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syntDenum, LPC_FILTERORDER+1, (int16_t)(2*iLBCenc_inst->state_short_len));
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for(k=0;k<iLBCenc_inst->state_short_len;k++){
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sampleAr[k] += sampleAr[k+iLBCenc_inst->state_short_len];
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}
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/* Find maximum absolute value in the vector */
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maxVal=WebRtcSpl_MaxAbsValueW16(sampleAr, iLBCenc_inst->state_short_len);
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/* Find the best index */
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if ((((int32_t)maxVal)<<scaleRes)<23170) {
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maxValsq=((int32_t)maxVal*maxVal)<<(2+2*scaleRes);
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} else {
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maxValsq=(int32_t)WEBRTC_SPL_WORD32_MAX;
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}
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index=0;
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for (i=0;i<63;i++) {
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if (maxValsq>=WebRtcIlbcfix_kChooseFrgQuant[i]) {
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index=i+1;
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} else {
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i=63;
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}
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}
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iLBC_encbits->idxForMax=index;
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/* Rescale the vector before quantization */
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scale=WebRtcIlbcfix_kScale[index];
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if (index<27) { /* scale table is in Q16, fout[] is in Q(-1) and we want the result to be in Q11 */
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shift=4;
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} else { /* scale table is in Q21, fout[] is in Q(-1) and we want the result to be in Q11 */
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shift=9;
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}
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/* Set up vectors for AbsQuant and rescale it with the scale factor */
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WebRtcSpl_ScaleVectorWithSat(sampleAr, sampleAr, scale,
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iLBCenc_inst->state_short_len, (int16_t)(shift-scaleRes));
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/* Quantize the values in fout[] */
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WebRtcIlbcfix_AbsQuant(iLBCenc_inst, iLBC_encbits, sampleAr, weightDenum);
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return;
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}
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