statesearchw.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

    StateSearchW.c 

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

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

#include <math.h> 
#include <string.h>

#include "iLBC_define.h"
#include "StateSearchW.h"
#include "constants.h"
#include "filter.h"
#include "helpfun.h"

/*----------------------------------------------------------------*
 *  predictive noise shaping encoding of scaled start state 
 *  (subrutine for StateSearchW) 
 *---------------------------------------------------------------*/

void AbsQuantW(
    iLBC_Enc_Inst_t *iLBCenc_inst,  
                        /* (i) Encoder instance */
    float *in,          /* (i) vector to encode */
    float *syntDenum,   /* (i) denominator of synthesis filter */
    float *weightDenum, /* (i) denominator of weighting filter */
    int *out,           /* (o) vector of quantizer indexes */
    int len,        /* (i) length of vector to encode and 
                               vector of quantizer indexes */
    int state_first     /* (i) position of start state in the 
                               80 vec */
){
    float *syntOut;
    float syntOutBuf[LPC_FILTERORDER+STATE_SHORT_LEN_30MS];
    float toQ, xq;
    int n;
    int index;

    /* initialization of buffer for filtering */
            
    memset(syntOutBuf, 0, LPC_FILTERORDER*sizeof(float));



    /* initialization of pointer for filtering */

    syntOut = &syntOutBuf[LPC_FILTERORDER];
    
    /* synthesis and weighting filters on input */
    
    if (state_first) {
        AllPoleFilter (in, weightDenum, SUBL, LPC_FILTERORDER);
    } else {
        AllPoleFilter (in, weightDenum, 
            iLBCenc_inst->state_short_len-SUBL, 
            LPC_FILTERORDER);
    }

    /* encoding loop */

    for (n=0; n<len; n++) {
        
        /* time update of filter coefficients */  
        
        if ((state_first)&&(n==SUBL)){
            syntDenum += (LPC_FILTERORDER+1);
            weightDenum += (LPC_FILTERORDER+1);

            /* synthesis and weighting filters on input */
            AllPoleFilter (&in[n], weightDenum, len-n, 
                LPC_FILTERORDER);

        } else if ((state_first==0)&&
            (n==(iLBCenc_inst->state_short_len-SUBL))) {
            syntDenum += (LPC_FILTERORDER+1);
            weightDenum += (LPC_FILTERORDER+1);

            /* synthesis and weighting filters on input */
            AllPoleFilter (&in[n], weightDenum, len-n, 
                LPC_FILTERORDER);
            
        }
        
        /* prediction of synthesized and weighted input */

        syntOut[n] = 0.0;
        AllPoleFilter (&syntOut[n], weightDenum, 1, 
            LPC_FILTERORDER);
        
        /* quantization */      

        toQ = in[n]-syntOut[n];
        sort_sq(&xq, &index, toQ, state_sq3Tbl, 8);
        out[n]=index;
        syntOut[n] = state_sq3Tbl[out[n]];

        /* update of the prediction filter */



        AllPoleFilter(&syntOut[n], weightDenum, 1, 
            LPC_FILTERORDER);
    }
}

/*----------------------------------------------------------------*
 *  encoding of start state                          
 *---------------------------------------------------------------*/

void StateSearchW( 
    iLBC_Enc_Inst_t *iLBCenc_inst,  
                        /* (i) Encoder instance */
    float *residual,/* (i) target residual vector */
    float *syntDenum,   /* (i) lpc synthesis filter */
    float *weightDenum, /* (i) weighting filter denuminator */
    int *idxForMax,     /* (o) quantizer index for maximum 
                               amplitude */
    int *idxVec,    /* (o) vector of quantization indexes */
    int len,        /* (i) length of all vectors */
    int state_first     /* (i) position of start state in the 
                               80 vec */
){  
    float dtmp, maxVal;
    float tmpbuf[LPC_FILTERORDER+2*STATE_SHORT_LEN_30MS];
    float *tmp, numerator[1+LPC_FILTERORDER]; 
    float foutbuf[LPC_FILTERORDER+2*STATE_SHORT_LEN_30MS], *fout;
    int k;
    float qmax, scal;
    
    /* initialization of buffers and filter coefficients */

    memset(tmpbuf, 0, LPC_FILTERORDER*sizeof(float));
    memset(foutbuf, 0, LPC_FILTERORDER*sizeof(float));
    for (k=0; k<LPC_FILTERORDER; k++) {
        numerator[k]=syntDenum[LPC_FILTERORDER-k];
    }
    numerator[LPC_FILTERORDER]=syntDenum[0];
    tmp = &tmpbuf[LPC_FILTERORDER];
    fout = &foutbuf[LPC_FILTERORDER];

    /* circular convolution with the all-pass filter */
    
    memcpy(tmp, residual, len*sizeof(float));
    memset(tmp+len, 0, len*sizeof(float));
    ZeroPoleFilter(tmp, numerator, syntDenum, 2*len, 
        LPC_FILTERORDER, fout);
    for (k=0; k<len; k++) {
        fout[k] += fout[k+len];
    }   
        
    /* identification of the maximum amplitude value */
    
    maxVal = fout[0];


    for (k=1; k<len; k++) {
        
        if (fout[k]*fout[k] > maxVal*maxVal){
            maxVal = fout[k];
        }
    }
    maxVal=(float)fabs(maxVal);
        
    /* encoding of the maximum amplitude value */
    
    if (maxVal < 10.0) {
        maxVal = 10.0;
    }
    maxVal = (float)log10(maxVal);
    sort_sq(&dtmp, idxForMax, maxVal, state_frgqTbl, 64);

    /* decoding of the maximum amplitude representation value,
       and corresponding scaling of start state */

    maxVal=state_frgqTbl[*idxForMax];
    qmax = (float)pow(10,maxVal);
    scal = (float)(4.5)/qmax;
    for (k=0; k<len; k++){
        fout[k] *= scal;
    }

    /* predictive noise shaping encoding of scaled start state */

    AbsQuantW(iLBCenc_inst, fout,syntDenum, 
        weightDenum,idxVec, len, state_first);
}