asterisk/codecs/ilbc/StateSearchW.c

 
/****************************************************************** 
 
    iLBC Speech Coder ANSI-C Source Code 
 
    StateSearchW.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" 
#include "helpfun.h" 
 
/*----------------------------------------------------------------* 
 *  predictive noise shaping encoding of scaled start state  
 *  (subrutine for StateSearchW)  
 *---------------------------------------------------------------*/ 
 
void AbsQuantW( 
    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, syntOutBuf[LPC_FILTERORDER+STATE_SHORT_LEN]; 
    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, 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==(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(  
    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, tmpbuf[LPC_FILTERORDER+2*STATE_SHORT_LEN]; 
    float *tmp, numerator[1+LPC_FILTERORDER];  
    float foutbuf[LPC_FILTERORDER+2*STATE_SHORT_LEN], *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(fout,syntDenum,weightDenum,idxVec, len, state_first); 
}