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/******************************************************************
iLBC Speech Coder ANSI-C Source Code
iCBConstruct.c
Copyright (C) The Internet Society (2004).
All Rights Reserved.
******************************************************************/
#include <math.h>
#include "iLBC_define.h"
#include "gainquant.h"
#include "getCBvec.h"
/*----------------------------------------------------------------*
* Convert the codebook indexes to make the search easier
*---------------------------------------------------------------*/
void index_conv_enc(
int *index /* (i/o) Codebook indexes */
){
int k;
for (k=1; k<CB_NSTAGES; k++) {
if ((index[k]>=108)&&(index[k]<172)) {
index[k]-=64;
} else if (index[k]>=236) {
index[k]-=128;
} else {
/* ERROR */
}
}
}
void index_conv_dec(
int *index /* (i/o) Codebook indexes */
){
int k;
for (k=1; k<CB_NSTAGES; k++) {
if ((index[k]>=44)&&(index[k]<108)) {
index[k]+=64;
} else if ((index[k]>=108)&&(index[k]<128)) {
index[k]+=128;
} else {
/* ERROR */
}
}
}
/*----------------------------------------------------------------*
* Construct decoded vector from codebook and gains.
*---------------------------------------------------------------*/
void iCBConstruct(
float *decvector, /* (o) Decoded vector */
int *index, /* (i) Codebook indices */
int *gain_index,/* (i) Gain quantization indices */
float *mem, /* (i) Buffer for codevector construction */
int lMem, /* (i) Length of buffer */
int veclen, /* (i) Length of vector */
int nStages /* (i) Number of codebook stages */
){
int j,k;
float gain[CB_NSTAGES];
float cbvec[SUBL];
/* gain de-quantization */
gain[0] = gaindequant(gain_index[0], 1.0, 32);
if (nStages > 1) {
gain[1] = gaindequant(gain_index[1],
(float)fabs(gain[0]), 16);
}
if (nStages > 2) {
gain[2] = gaindequant(gain_index[2],
(float)fabs(gain[1]), 8);
}
/* codebook vector construction and construction of
total vector */
getCBvec(cbvec, mem, index[0], lMem, veclen);
for (j=0;j<veclen;j++){
decvector[j] = gain[0]*cbvec[j];
}
if (nStages > 1) {
for (k=1; k<nStages; k++) {
getCBvec(cbvec, mem, index[k], lMem, veclen);
for (j=0;j<veclen;j++) {
decvector[j] += gain[k]*cbvec[j];
}
}
}
}
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