asterisk/codecs/ilbc/StateSearchW.c

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2023-05-25 18:45:57 +00:00
/******************************************************************
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
* (subroutine 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 denumerator */
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);
}