StateSearchW.c

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

 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 "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);
 }