enhancer.c

PA1688网络电话机全部源程序

    
   /****************************************************************** 
    
       iLBC Speech Coder ANSI-C Source Code 
    
       enhancer.c  
    
       Copyright (c) 2001, 
       Global IP Sound AB. 
       All rights reserved. 
    
   ******************************************************************/ 
    
   #include <math.h> 
   #include <string.h> 
   #include "iLBC_define.h" 
   #include "constants.h" 
   #include "filter.h" 
    
   /*----------------------------------------------------------------* 
    * Find index in array such that the array element with said 
    * index is the element of said array closest to "value"  
    * according to the squared-error criterion 
    *---------------------------------------------------------------*/ 
     
    
    
    
   void NearestNeighbor( 
       int   *index,   /* (o) index of array element closest to value */ 
       float *array,   /* (i) data array */ 
       float value,/* (i) value */ 
       int arlength/* (i) dimension of data array */ 
   ){ 
       int i; 
       float bestcrit,crit; 
    
       crit=array[0]-value; 
       bestcrit=crit*crit; 
       *index=0; 
       for (i=1; i<arlength; i++) { 
           crit=array[i]-value; 
           crit=crit*crit; 
            
           if (crit<bestcrit) { 
               bestcrit=crit; 
               *index=i; 
           } 
       } 
   } 
    
   /*----------------------------------------------------------------* 
    * compute cross correlation between sequences 
    *---------------------------------------------------------------*/ 
    
   void mycorr1(  
       float* corr,    /* (o) correlation of seq1 and seq2 */ 
       float* seq1,    /* (i) first sequence */ 
       int dim1,           /* (i) dimension first seq1 */ 
       const float *seq2,  /* (i) second sequence */ 
       int dim2        /* (i) dimension seq2 */ 
   ){ 
       int i,j; 
    
       for (i=0; i<=dim1-dim2; i++) { 
           corr[i]=0.0; 
           for (j=0; j<dim2; j++) { 
               corr[i] += seq1[i+j] * seq2[j]; 
           } 
       } 
   } 
    
   /*----------------------------------------------------------------* 
    * upsample finite array assuming zeros outside bounds 
    *---------------------------------------------------------------*/ 
    
   void enh_upsample(  
       float* useq1,   /* (o) upsampled output sequence */ 
       float* seq1,/* (i) unupsampled sequence */ 
       int dim1,       /* (i) dimension seq1 */ 
     
    
    
       int hfl         /* (i) polyphase filter length=2*hfl+1 */ 
   ){ 
       float *pu,*ps; 
       int i,j,k,q,filterlength,hfl2; 
       const float *polyp[ENH_UPS0]; /* pointers to polyphase columns */ 
       const float *pp; 
    
       /* define pointers for filter */ 
    
       filterlength=2*hfl+1; 
        
       if ( filterlength > dim1 ) { 
           hfl2=(int) (dim1/2); 
           for (j=0; j<ENH_UPS0; j++) { 
               polyp[j]=polyphaserTbl+j*filterlength+hfl-hfl2; 
           } 
           hfl=hfl2; 
           filterlength=2*hfl+1; 
       } 
       else { 
           for (j=0; j<ENH_UPS0; j++) { 
               polyp[j]=polyphaserTbl+j*filterlength; 
           } 
       } 
    
       /* filtering: filter overhangs left side of sequence */ 
    
       pu=useq1; 
       for (i=hfl; i<filterlength; i++) {  
           for (j=0; j<ENH_UPS0; j++) { 
               *pu=0.0; 
               pp = polyp[j]; 
               ps = seq1+i; 
               for (k=0; k<=i; k++) { 
                   *pu += *ps-- * *pp++; 
               } 
               pu++; 
           } 
       } 
    
       /* filtering: simple convolution=inner products */ 
    
       for (i=filterlength; i<dim1; i++) { 
           for (j=0;j<ENH_UPS0; j++){ 
               *pu=0.0; 
               pp = polyp[j]; 
               ps = seq1+i; 
               for (k=0; k<filterlength; k++) { 
                   *pu += *ps-- * *pp++; 
               } 
               pu++; 
           } 
       } 
     
    
    
    
       /* filtering: filter overhangs right side of sequence */ 
    
       for (q=1; q<=hfl; q++) {  
           for (j=0; j<ENH_UPS0; j++) { 
               *pu=0.0; 
               pp = polyp[j]+q; 
               ps = seq1+dim1-1; 
               for (k=0; k<filterlength-q; k++) { 
                   *pu += *ps-- * *pp++; 
               } 
               pu++; 
           } 
       } 
   } 
    
    
   /*----------------------------------------------------------------* 
    * find segment starting near idata+estSegPos that has highest  
    * correlation with idata+centerStartPos through  
    * idata+centerStartPos+ENH_BLOCKL-1 segment is found at a  
    * resolution of ENH_UPSO times the original of the original  
    * sampling rate 
    *---------------------------------------------------------------*/ 
    
   void refiner( 
       float *seg,         /* (o) segment array */ 
       float *updStartPos, /* (o) updated start point */ 
       float* idata,       /* (i) original data buffer */ 
       int idatal,         /* (i) dimension of idata */ 
       int centerStartPos, /* (i) beginning center segment */ 
       float estSegPos,/* (i) estimated beginning other segment */ 
       float period    /* (i) estimated pitch period */ 
   ){ 
       int estSegPosRounded,searchSegStartPos,searchSegEndPos,corrdim; 
       int tloc,tloc2,i,st,en,fraction; 
       float vect[ENH_VECTL],corrVec[ENH_CORRDIM],maxv; 
       float corrVecUps[ENH_CORRDIM*ENH_UPS0]; 
    
       /* defining array bounds */ 
        
       estSegPosRounded=(int)(estSegPos - 0.5); 
    
       searchSegStartPos=estSegPosRounded-ENH_SLOP; 
        
       if (searchSegStartPos<0) {  
           searchSegStartPos=0; 
       } 
       searchSegEndPos=estSegPosRounded+ENH_SLOP; 
        
       if (searchSegEndPos+ENH_BLOCKL >= idatal) {  
           searchSegEndPos=idatal-ENH_BLOCKL-1; 
       } 
     
    
    
       corrdim=searchSegEndPos-searchSegStartPos+1; 
        
       /* compute upsampled correlation (corr33) and find  
          location of max */ 
    
       mycorr1(corrVec,idata+searchSegStartPos, 
           corrdim+ENH_BLOCKL-1,idata+centerStartPos,ENH_BLOCKL); 
       enh_upsample(corrVecUps,corrVec,corrdim,ENH_FL0); 
       tloc=0; maxv=corrVecUps[0]; 
       for (i=1; i<ENH_UPS0*corrdim; i++) { 
            
           if (corrVecUps[i]>maxv) { 
               tloc=i; 
               maxv=corrVecUps[i]; 
           } 
       } 
        
       /* make vector can be upsampled without ever running outside  
          bounds */ 
        
       *updStartPos= (float)searchSegStartPos +  
           (float)tloc/(float)ENH_UPS0+(float)1.0; 
       tloc2=(int)(tloc/ENH_UPS0); 
        
       if (tloc>tloc2*ENH_UPS0) { 
           tloc2++; 
       } 
       st=searchSegStartPos+tloc2-ENH_FL0; 
        
       if (st<0) { 
           memset(vect,0,-st*sizeof(float)); 
           memcpy(&vect[-st],idata, (ENH_VECTL+st)*sizeof(float)); 
       } 
       else { 
           en=st+ENH_VECTL; 
            
           if (en>idatal) { 
               memcpy(vect, &idata[st],  
                   (ENH_VECTL-(en-idatal))*sizeof(float)); 
               memset(&vect[ENH_VECTL-(en-idatal)], 0,  
                   (en-idatal)*sizeof(float)); 
           } 
           else { 
               memcpy(vect, &idata[st], ENH_VECTL*sizeof(float)); 
           } 
       } 
       fraction=tloc2*ENH_UPS0-tloc; 
        
       /* compute the segment (this is actually a convolution) */ 
    
       mycorr1(seg,vect,ENH_VECTL,polyphaserTbl+(2*ENH_FL0+1)*fraction, 
           2*ENH_FL0+1); 
   } 
     
    
    
    
   /*----------------------------------------------------------------* 
    * find the smoothed output data 
    *---------------------------------------------------------------*/ 
    
   void smath( 
       float *odata,   /* (o) smoothed output */ 
       float *sseq,/* (i) said second sequence of waveforms */ 
       int hl,         /* (i) 2*hl+1 is sseq dimension */ 
       float alpha0/* (i) max smoothing energy fraction */ 
   ){ 
       int i,k; 
       float w00,w10,w11,A,B,C,*psseq,err,errs; 
       float surround[BLOCKL_MAX]; /* shape contributed by other than  
                                      current */ 
       float wt[2*ENH_HL+1];       /* waveform weighting to get  
                                      surround shape */ 
       float denom; 
        
       /* create shape of contribution from all waveforms except the 
          current one */ 
    
       for (i=1; i<=2*hl+1; i++) { 
           wt[i-1] = (float)0.5*(1 - (float)cos(2*PI*i/(2*hl+2)));  
       } 
       wt[hl]=0.0; /* for clarity, not used */ 
       for (i=0; i<ENH_BLOCKL; i++) { 
           surround[i]=sseq[i]*wt[0]; 
       } 
       for (k=1; k<hl; k++) { 
           psseq=sseq+k*ENH_BLOCKL; 
           for(i=0;i<ENH_BLOCKL; i++) { 
               surround[i]+=psseq[i]*wt[k]; 
           } 
       } 
       for (k=hl+1; k<=2*hl; k++) { 
           psseq=sseq+k*ENH_BLOCKL; 
           for(i=0;i<ENH_BLOCKL; i++) { 
               surround[i]+=psseq[i]*wt[k]; 
           } 
       } 
        
       /* compute some inner products */ 
    
       w00 = w10 = w11 = 0.0; 
       psseq=sseq+hl*ENH_BLOCKL; /* current block  */ 
       for (i=0; i<ENH_BLOCKL;i++) { 
           w00+=psseq[i]*psseq[i]; 
           w11+=surround[i]*surround[i]; 
           w10+=surround[i]*psseq[i]; 
       } 
        
       if (fabs(w11) < 1.0) { 
     
    
    
           w11=1.0; 
       } 
       C = (float)sqrt( w00/w11); 
        
       /* first try enhancement without power-constraint */ 
    
       errs=0.0; 
       psseq=sseq+hl*ENH_BLOCKL; 
       for (i=0; i<ENH_BLOCKL; i++) { 
           odata[i]=C*surround[i]; 
           err=psseq[i]-odata[i]; 
           errs+=err*err; 
       } 
        
       /* if constraint violated by first try, add constraint */  
        
       if (errs > alpha0 * w00) { 
           if ( w00 < 1) { 
               w00=1; 
           } 
           denom = (w11*w00-w10*w10)/(w00*w00); 
            
           if (denom > 0.0001) { /* eliminates numerical problems  
                                    for if smooth */ 
               A = (float)sqrt( (alpha0- alpha0*alpha0/4)/denom);