504 lines
14 KiB
C
504 lines
14 KiB
C
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/******************************************************************
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iLBC Speech Coder ANSI-C Source Code
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iCBSearch.c
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Copyright (C) The Internet Society (2004).
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All Rights Reserved.
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******************************************************************/
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#include <math.h>
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#include <string.h>
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#include "iLBC_define.h"
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#include "gainquant.h"
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#include "createCB.h"
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#include "filter.h"
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#include "constants.h"
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/*----------------------------------------------------------------*
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* Search routine for codebook encoding and gain quantization.
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*---------------------------------------------------------------*/
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void iCBSearch(
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iLBC_Enc_Inst_t *iLBCenc_inst,
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/* (i) the encoder state structure */
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int *index, /* (o) Codebook indices */
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int *gain_index,/* (o) Gain quantization indices */
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float *intarget,/* (i) Target vector for encoding */
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float *mem, /* (i) Buffer for codebook construction */
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int lMem, /* (i) Length of buffer */
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int lTarget, /* (i) Length of vector */
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int nStages, /* (i) Number of codebook stages */
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float *weightDenum, /* (i) weighting filter coefficients */
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float *weightState, /* (i) weighting filter state */
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int block /* (i) the sub-block number */
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){
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int i, j, icount, stage, best_index, range, counter;
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float max_measure, gain, measure, crossDot, ftmp;
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float gains[CB_NSTAGES];
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float target[SUBL];
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int base_index, sInd, eInd, base_size;
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int sIndAug=0, eIndAug=0;
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float buf[CB_MEML+SUBL+2*LPC_FILTERORDER];
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float invenergy[CB_EXPAND*128], energy[CB_EXPAND*128];
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float *pp, *ppi=0, *ppo=0, *ppe=0;
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float cbvectors[CB_MEML];
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float tene, cene, cvec[SUBL];
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float aug_vec[SUBL];
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memset(cvec,0,SUBL*sizeof(float));
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/* Determine size of codebook sections */
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base_size=lMem-lTarget+1;
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if (lTarget==SUBL) {
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base_size=lMem-lTarget+1+lTarget/2;
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}
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/* setup buffer for weighting */
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memcpy(buf,weightState,sizeof(float)*LPC_FILTERORDER);
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memcpy(buf+LPC_FILTERORDER,mem,lMem*sizeof(float));
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memcpy(buf+LPC_FILTERORDER+lMem,intarget,lTarget*sizeof(float));
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/* weighting */
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AllPoleFilter(buf+LPC_FILTERORDER, weightDenum,
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lMem+lTarget, LPC_FILTERORDER);
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/* Construct the codebook and target needed */
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memcpy(target, buf+LPC_FILTERORDER+lMem, lTarget*sizeof(float));
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tene=0.0;
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for (i=0; i<lTarget; i++) {
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tene+=target[i]*target[i];
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}
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/* Prepare search over one more codebook section. This section
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is created by filtering the original buffer with a filter. */
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filteredCBvecs(cbvectors, buf+LPC_FILTERORDER, lMem);
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/* The Main Loop over stages */
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for (stage=0; stage<nStages; stage++) {
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range = search_rangeTbl[block][stage];
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/* initialize search measure */
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max_measure = (float)-10000000.0;
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gain = (float)0.0;
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best_index = 0;
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/* Compute cross dot product between the target
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and the CB memory */
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crossDot=0.0;
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pp=buf+LPC_FILTERORDER+lMem-lTarget;
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for (j=0; j<lTarget; j++) {
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crossDot += target[j]*(*pp++);
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}
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if (stage==0) {
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/* Calculate energy in the first block of
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'lTarget' samples. */
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ppe = energy;
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ppi = buf+LPC_FILTERORDER+lMem-lTarget-1;
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ppo = buf+LPC_FILTERORDER+lMem-1;
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*ppe=0.0;
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pp=buf+LPC_FILTERORDER+lMem-lTarget;
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for (j=0; j<lTarget; j++, pp++) {
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*ppe+=(*pp)*(*pp);
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}
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if (*ppe>0.0) {
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invenergy[0] = (float) 1.0 / (*ppe + EPS);
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} else {
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invenergy[0] = (float) 0.0;
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}
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ppe++;
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measure=(float)-10000000.0;
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if (crossDot > 0.0) {
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measure = crossDot*crossDot*invenergy[0];
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}
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}
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else {
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measure = crossDot*crossDot*invenergy[0];
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}
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/* check if measure is better */
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ftmp = crossDot*invenergy[0];
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if ((measure>max_measure) && (fabs(ftmp)<CB_MAXGAIN)) {
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best_index = 0;
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max_measure = measure;
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gain = ftmp;
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}
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/* loop over the main first codebook section,
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full search */
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for (icount=1; icount<range; icount++) {
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/* calculate measure */
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crossDot=0.0;
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pp = buf+LPC_FILTERORDER+lMem-lTarget-icount;
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for (j=0; j<lTarget; j++) {
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crossDot += target[j]*(*pp++);
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}
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if (stage==0) {
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*ppe++ = energy[icount-1] + (*ppi)*(*ppi) -
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(*ppo)*(*ppo);
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ppo--;
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ppi--;
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if (energy[icount]>0.0) {
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invenergy[icount] =
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(float)1.0/(energy[icount]+EPS);
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} else {
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invenergy[icount] = (float) 0.0;
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}
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measure=(float)-10000000.0;
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if (crossDot > 0.0) {
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measure = crossDot*crossDot*invenergy[icount];
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}
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}
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else {
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measure = crossDot*crossDot*invenergy[icount];
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}
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/* check if measure is better */
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ftmp = crossDot*invenergy[icount];
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if ((measure>max_measure) && (fabs(ftmp)<CB_MAXGAIN)) {
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best_index = icount;
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max_measure = measure;
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gain = ftmp;
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}
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}
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/* Loop over augmented part in the first codebook
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* section, full search.
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* The vectors are interpolated.
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*/
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if (lTarget==SUBL) {
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/* Search for best possible cb vector and
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compute the CB-vectors' energy. */
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searchAugmentedCB(20, 39, stage, base_size-lTarget/2,
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target, buf+LPC_FILTERORDER+lMem,
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&max_measure, &best_index, &gain, energy,
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invenergy);
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}
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/* set search range for following codebook sections */
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base_index=best_index;
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/* unrestricted search */
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if (CB_RESRANGE == -1) {
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sInd=0;
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eInd=range-1;
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sIndAug=20;
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eIndAug=39;
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}
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/* restricted search around best index from first
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codebook section */
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else {
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/* Initialize search indices */
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sIndAug=0;
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eIndAug=0;
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sInd=base_index-CB_RESRANGE/2;
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eInd=sInd+CB_RESRANGE;
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if (lTarget==SUBL) {
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if (sInd<0) {
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sIndAug = 40 + sInd;
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eIndAug = 39;
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sInd=0;
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} else if ( base_index < (base_size-20) ) {
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if (eInd > range) {
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sInd -= (eInd-range);
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eInd = range;
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}
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} else { /* base_index >= (base_size-20) */
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if (sInd < (base_size-20)) {
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sIndAug = 20;
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sInd = 0;
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eInd = 0;
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eIndAug = 19 + CB_RESRANGE;
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if(eIndAug > 39) {
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eInd = eIndAug-39;
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eIndAug = 39;
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}
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} else {
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sIndAug = 20 + sInd - (base_size-20);
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eIndAug = 39;
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sInd = 0;
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eInd = CB_RESRANGE - (eIndAug-sIndAug+1);
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}
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}
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} else { /* lTarget = 22 or 23 */
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if (sInd < 0) {
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eInd -= sInd;
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sInd = 0;
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}
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if(eInd > range) {
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sInd -= (eInd - range);
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eInd = range;
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}
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}
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}
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/* search of higher codebook section */
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/* index search range */
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counter = sInd;
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sInd += base_size;
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eInd += base_size;
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if (stage==0) {
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ppe = energy+base_size;
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*ppe=0.0;
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pp=cbvectors+lMem-lTarget;
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for (j=0; j<lTarget; j++, pp++) {
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*ppe+=(*pp)*(*pp);
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}
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ppi = cbvectors + lMem - 1 - lTarget;
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ppo = cbvectors + lMem - 1;
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for (j=0; j<(range-1); j++) {
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*(ppe+1) = *ppe + (*ppi)*(*ppi) - (*ppo)*(*ppo);
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ppo--;
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ppi--;
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ppe++;
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}
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}
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/* loop over search range */
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for (icount=sInd; icount<eInd; icount++) {
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/* calculate measure */
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crossDot=0.0;
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pp=cbvectors + lMem - (counter++) - lTarget;
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for (j=0;j<lTarget;j++) {
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crossDot += target[j]*(*pp++);
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}
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if (energy[icount]>0.0) {
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invenergy[icount] =(float)1.0/(energy[icount]+EPS);
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} else {
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invenergy[icount] =(float)0.0;
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}
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if (stage==0) {
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measure=(float)-10000000.0;
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if (crossDot > 0.0) {
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measure = crossDot*crossDot*
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invenergy[icount];
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}
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}
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else {
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measure = crossDot*crossDot*invenergy[icount];
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}
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/* check if measure is better */
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ftmp = crossDot*invenergy[icount];
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if ((measure>max_measure) && (fabs(ftmp)<CB_MAXGAIN)) {
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best_index = icount;
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max_measure = measure;
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gain = ftmp;
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}
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}
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/* Search the augmented CB inside the limited range. */
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if ((lTarget==SUBL)&&(sIndAug!=0)) {
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searchAugmentedCB(sIndAug, eIndAug, stage,
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2*base_size-20, target, cbvectors+lMem,
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&max_measure, &best_index, &gain, energy,
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invenergy);
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}
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/* record best index */
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index[stage] = best_index;
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/* gain quantization */
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if (stage==0){
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if (gain<0.0){
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gain = 0.0;
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}
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if (gain>CB_MAXGAIN) {
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gain = (float)CB_MAXGAIN;
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}
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gain = gainquant(gain, 1.0, 32, &gain_index[stage]);
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}
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else {
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if (stage==1) {
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gain = gainquant(gain, (float)fabs(gains[stage-1]),
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16, &gain_index[stage]);
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} else {
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gain = gainquant(gain, (float)fabs(gains[stage-1]),
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8, &gain_index[stage]);
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}
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}
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/* Extract the best (according to measure)
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codebook vector */
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if (lTarget==(STATE_LEN-iLBCenc_inst->state_short_len)) {
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if (index[stage]<base_size) {
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pp=buf+LPC_FILTERORDER+lMem-lTarget-index[stage];
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} else {
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pp=cbvectors+lMem-lTarget-
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index[stage]+base_size;
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}
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} else {
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if (index[stage]<base_size) {
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if (index[stage]<(base_size-20)) {
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pp=buf+LPC_FILTERORDER+lMem-
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lTarget-index[stage];
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} else {
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createAugmentedVec(index[stage]-base_size+40,
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buf+LPC_FILTERORDER+lMem,aug_vec);
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pp=aug_vec;
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}
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} else {
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int filterno, position;
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filterno=index[stage]/base_size;
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position=index[stage]-filterno*base_size;
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if (position<(base_size-20)) {
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pp=cbvectors+filterno*lMem-lTarget-
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index[stage]+filterno*base_size;
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} else {
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createAugmentedVec(
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index[stage]-(filterno+1)*base_size+40,
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cbvectors+filterno*lMem,aug_vec);
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pp=aug_vec;
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}
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}
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}
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/* Subtract the best codebook vector, according
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to measure, from the target vector */
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for (j=0;j<lTarget;j++) {
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cvec[j] += gain*(*pp);
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target[j] -= gain*(*pp++);
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}
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/* record quantized gain */
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gains[stage]=gain;
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}/* end of Main Loop. for (stage=0;... */
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/* Gain adjustment for energy matching */
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cene=0.0;
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for (i=0; i<lTarget; i++) {
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cene+=cvec[i]*cvec[i];
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}
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j=gain_index[0];
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for (i=gain_index[0]; i<32; i++) {
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ftmp=cene*gain_sq5Tbl[i]*gain_sq5Tbl[i];
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if ((ftmp<(tene*gains[0]*gains[0])) &&
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(gain_sq5Tbl[j]<(2.0*gains[0]))) {
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j=i;
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}
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}
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gain_index[0]=j;
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}
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