StateConstructW.h File Reference

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Functions
void	StateConstructW (int idxForMax, int *idxVec, float *syntDenum, float *out, int len)

Function Documentation

StateConstructW()

void StateConstructW	(	int	idxForMax,
		int *	idxVec,
		float *	syntDenum,
		float *	out,
		int	len
	)

Definition at line 24 of file StateConstructW.c.

References len(), LPC_FILTERORDER, state_frgqTbl, STATE_LEN, state_sq3Tbl, tmp(), and ZeroPoleFilter().

Referenced by Decode(), and iLBC_encode().

    {
       float maxVal, tmpbuf[LPC_FILTERORDER+2*STATE_LEN], *tmp,
           numerator[LPC_FILTERORDER+1];
       float foutbuf[LPC_FILTERORDER+2*STATE_LEN], *fout;
       int k,tmpi;

       /* decoding of the maximum value */

       maxVal = state_frgqTbl[idxForMax];
       maxVal = (float)pow(10,maxVal)/(float)4.5;

       /* initialization of buffers and 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];

       /* decoding of the sample values */

       for (k=0; k<len; k++) {
           tmpi = len-1-k;
           /* maxVal = 1/scal */
           tmp[k] = maxVal*state_sq3Tbl[idxVec[tmpi]];
       }

       /* circular convolution with all-pass filter */

       memset(tmp+len, 0, len*sizeof(float));
       ZeroPoleFilter(tmp, numerator, syntDenum, 2*len,
           LPC_FILTERORDER, fout);
       for (k=0;k<len;k++) {
           out[k] = fout[len-1-k]+fout[2*len-1-k];
       }
   }