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