createcb.c

PA1688网络电话机全部源程序

    
   /****************************************************************** 
    
       iLBC Speech Coder ANSI-C Source Code 
    
       createCB.c 
    
       Copyright (c) 2001, 
       Global IP Sound AB. 
       All rights reserved. 
    
     
    
    
   ******************************************************************/ 
    
   #include "iLBC_define.h" 
   #include "constants.h" 
   #include <string.h> 
   #include <math.h> 
    
   /*----------------------------------------------------------------* 
    *  Construct an additional codebook vector by filtering the 
    *  initial codebook buffer. This vector is then used to expand 
    *  the codebook with an additional section. 
    *---------------------------------------------------------------*/ 
    
   void filteredCBvecs( 
       float *cbvectors,   /* (o) Codebook vectors for the  
                                  higher section */ 
       float *mem,         /* (i) Buffer to create codebook  
                                  vector from */ 
       int lMem        /* (i) Length of buffer */ 
   ){ 
       int j, k; 
       float *pp, *pp1; 
       float tempbuff2[CB_MEML+CB_FILTERLEN]; 
       float *pos; 
    
       memset(tempbuff2, 0, (CB_HALFFILTERLEN-1)*sizeof(float)); 
       memcpy(&tempbuff2[CB_HALFFILTERLEN-1], mem, lMem*sizeof(float)); 
       memset(&tempbuff2[lMem+CB_HALFFILTERLEN-1], 0,  
           (CB_HALFFILTERLEN+1)*sizeof(float)); 
    
       /* Create codebook vector for higher section by filtering */ 
    
       /* do filtering */ 
       pos=cbvectors; 
       memset(pos, 0, lMem*sizeof(float)); 
       for (k=0; k<lMem; k++) { 
           pp=&tempbuff2[k]; 
           pp1=&cbfiltersTbl[0]; 
           for (j=0;j<CB_FILTERLEN;j++) { 
               (*pos)+=(*pp++)*(*pp1++); 
           } 
           pos++; 
       } 
   } 
    
   /*----------------------------------------------------------------* 
    *  Search the augmented part of the codebook to find the best 
    *  measure. 
    *----------------------------------------------------------------*/ 
    
   void searchAugmentedCB( 
       int low,        /* (i) Start index for the search */ 
       int high,           /* (i) End index for the search */ 
     
    
    
       int stage,          /* (i) Current stage */ 
       int startIndex,     /* (i) Codebook index for the first  
                                  aug vector */ 
       float *target,      /* (i) Target vector for encoding */ 
       float *buffer,      /* (i) Pointer to the end of the buffer for 
                                  augmented codebook construction */ 
       float *max_measure, /* (i/o) Currently maximum measure */ 
       int *best_index,/* (o) Currently the best index */ 
       float *gain,    /* (o) Currently the best gain */ 
       float *energy,      /* (o) Energy of augmented codebook  
                                  vectors */ 
       float *invenergy/* (o) Inv energy of augmented codebook  
                                  vectors */ 
   ) { 
       int lagcount, ilow, j, tmpIndex; 
       float *pp, *ppo, *ppi, *ppe, crossDot, alfa;  
       float weighted, measure, nrjRecursive; 
       float ftmp; 
    
       /* Compute the energy for the first (low-5)  
          noninterpolated samples */ 
       nrjRecursive = (float) 0.0; 
       pp = buffer - low + 1; 
       for (j=0; j<(low-5); j++) { 
           nrjRecursive += ( (*pp)*(*pp) ); 
           pp++; 
       } 
       ppe = buffer - low; 
    
    
       for (lagcount=low; lagcount<=high; lagcount++) { 
    
           /* Index of the codebook vector used for retrieving  
              energy values */ 
           tmpIndex = startIndex+lagcount-20; 
    
           ilow = lagcount-4; 
                
           /* Update the energy recursively to save complexity */ 
           nrjRecursive = nrjRecursive + (*ppe)*(*ppe); 
           ppe--; 
           energy[tmpIndex] = nrjRecursive; 
    
           /* Compute cross dot product for the first (low-5) samples */ 
           crossDot = (float) 0.0; 
           pp = buffer-lagcount; 
           for (j=0; j<ilow; j++) { 
               crossDot += target[j]*(*pp++); 
           } 
    
           /* interpolation */ 
           alfa = (float) 0.2; 
           ppo = buffer-4; 
     
    
    
           ppi = buffer-lagcount-4; 
           for (j=ilow; j<lagcount; j++) { 
               weighted = ((float)1.0-alfa)*(*ppo)+alfa*(*ppi); 
               ppo++; 
               ppi++; 
               energy[tmpIndex] += weighted*weighted; 
               crossDot += target[j]*weighted; 
               alfa += (float)0.2; 
           } 
    
           /* Compute energy and cross dot product for the  
              remaining samples */ 
           pp = buffer - lagcount; 
           for (j=lagcount; j<SUBL; j++) { 
               energy[tmpIndex] += (*pp)*(*pp); 
               crossDot += target[j]*(*pp++); 
           } 
            
           if (energy[tmpIndex]>0.0) { 
               invenergy[tmpIndex]=(float)1.0/(energy[tmpIndex]+EPS); 
           } else { 
               invenergy[tmpIndex] = (float) 0.0; 
           } 
            
           if (stage==0) { 
               measure = (float)-10000000.0; 
                
               if (crossDot > 0.0) { 
                   measure = crossDot*crossDot*invenergy[tmpIndex]; 
               } 
           } 
           else { 
               measure = crossDot*crossDot*invenergy[tmpIndex]; 
           } 
        
           /* check if measure is better */ 
           ftmp = crossDot*invenergy[tmpIndex]; 
            
           if ((measure>*max_measure) && (fabs(ftmp)<CB_MAXGAIN)) { 
               *best_index = tmpIndex; 
               *max_measure = measure; 
               *gain = ftmp; 
           } 
       } 
   } 
    
    
   /*----------------------------------------------------------------* 
    *  Recreate a specific codebook vector from the augmented part. 
    * 
    *----------------------------------------------------------------*/ 
    
   void createAugmentedVec( 
     
    
    
       int index,      /* (i) Index for the augmented vector  
                              to be created */ 
       float *buffer,  /* (i) Pointer to the end of the buffer for 
                              augmented codebook construction */ 
       float *cbVec/* (o) The construced codebook vector */ 
   ) { 
       int ilow, j; 
       float *pp, *ppo, *ppi, alfa, alfa1, weighted; 
    
       ilow = index-5; 
                
       /* copy the first noninterpolated part */ 
    
       pp = buffer-index; 
       memcpy(cbVec,pp,sizeof(float)*index); 
    
       /* interpolation */ 
    
       alfa1 = (float)0.2; 
       alfa = 0.0; 
       ppo = buffer-5; 
       ppi = buffer-index-5; 
       for (j=ilow; j<index; j++) { 
           weighted = ((float)1.0-alfa)*(*ppo)+alfa*(*ppi); 
           ppo++; 
           ppi++; 
           cbVec[j] = weighted; 
           alfa += alfa1; 
       } 
    
       /* copy the second noninterpolated part */ 
    
       pp = buffer - index; 
       memcpy(cbVec+index,pp,sizeof(float)*(SUBL-index)); 
   }