iCBSearch.c

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