enhancer.c

视频监控vc源代码.对于做视频系统的朋友们很有帮助

/******************************************************************

    iLBC Speech Coder ANSI-C Source Code

    enhancer.c 

    Copyright (C) The Internet Society (2004). 
    All Rights Reserved.

******************************************************************/

#include <math.h>
#include <string.h>
#include "iLBC_define.h"
#include "enhancer.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
 *---------------------------------------------------------------*/

static 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
 *---------------------------------------------------------------*/

static 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
 *---------------------------------------------------------------*/



static 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
 *---------------------------------------------------------------*/

static 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
 *---------------------------------------------------------------*/

static 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);
            B = -alpha0/2 - A * w10/w00;
            B = B+1;
        }
        else { /* essentially no difference between cycles; 
                  smoothing not needed */