getCBvec.c

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

 iLBC Speech Coder ANSI-C Source Code

 getCBvec.c

 Copyright (C) The Internet Society (2004).
 All Rights Reserved.

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

 #include "iLBC_define.h"
 #include "constants.h"
 #include <string.h>

 /*----------------------------------------------------------------*
 * Construct codebook vector for given index.
 *---------------------------------------------------------------*/

 void getCBvec(





 float *cbvec, /* (o) Constructed codebook vector */
 float *mem, /* (i) Codebook buffer */
 int index, /* (i) Codebook index */
 int lMem, /* (i) Length of codebook buffer */
 int cbveclen/* (i) Codebook vector length */
 ){
 int j, k, n, memInd, sFilt;
 float tmpbuf[CB_MEML];
 int base_size;
 int ilow, ihigh;
 float alfa, alfa1;

 /* Determine size of codebook sections */

 base_size=lMem-cbveclen+1;

 if (cbveclen==SUBL) {
 base_size+=cbveclen/2;
 }

 /* No filter -> First codebook section */

 if (index<lMem-cbveclen+1) {

 /* first non-interpolated vectors */

 k=index+cbveclen;
 /* get vector */
 memcpy(cbvec, mem+lMem-k, cbveclen*sizeof(float));

 } else if (index < base_size) {

 k=2*(index-(lMem-cbveclen+1))+cbveclen;

 ihigh=k/2;
 ilow=ihigh-5;

 /* Copy first noninterpolated part */

 memcpy(cbvec, mem+lMem-k/2, ilow*sizeof(float));

 /* interpolation */

 alfa1=(float)0.2;
 alfa=0.0;
 for (j=ilow; j<ihigh; j++) {
 cbvec[j]=((float)1.0-alfa)*mem[lMem-k/2+j]+
 alfa*mem[lMem-k+j];





 alfa+=alfa1;
 }

 /* Copy second noninterpolated part */

 memcpy(cbvec+ihigh, mem+lMem-k+ihigh,
 (cbveclen-ihigh)*sizeof(float));

 }

 /* Higher codebook section based on filtering */

 else {

 /* first non-interpolated vectors */

 if (index-base_size<lMem-cbveclen+1) {
 float tempbuff2[CB_MEML+CB_FILTERLEN+1];
 float *pos;
 float *pp, *pp1;

 memset(tempbuff2, 0,
 CB_HALFFILTERLEN*sizeof(float));
 memcpy(&tempbuff2[CB_HALFFILTERLEN], mem,
 lMem*sizeof(float));
 memset(&tempbuff2[lMem+CB_HALFFILTERLEN], 0,
 (CB_HALFFILTERLEN+1)*sizeof(float));

 k=index-base_size+cbveclen;
 sFilt=lMem-k;
 memInd=sFilt+1-CB_HALFFILTERLEN;

 /* do filtering */
 pos=cbvec;
 memset(pos, 0, cbveclen*sizeof(float));
 for (n=0; n<cbveclen; n++) {
 pp=&tempbuff2[memInd+n+CB_HALFFILTERLEN];
 pp1=&cbfiltersTbl[CB_FILTERLEN-1];
 for (j=0; j<CB_FILTERLEN; j++) {
 (*pos)+=(*pp++)*(*pp1--);
 }
 pos++;
 }
 }

 /* interpolated vectors */

 else {





 float tempbuff2[CB_MEML+CB_FILTERLEN+1];

 float *pos;
 float *pp, *pp1;
 int i;

 memset(tempbuff2, 0,
 CB_HALFFILTERLEN*sizeof(float));
 memcpy(&tempbuff2[CB_HALFFILTERLEN], mem,
 lMem*sizeof(float));
 memset(&tempbuff2[lMem+CB_HALFFILTERLEN], 0,
 (CB_HALFFILTERLEN+1)*sizeof(float));

 k=2*(index-base_size-
 (lMem-cbveclen+1))+cbveclen;
 sFilt=lMem-k;
 memInd=sFilt+1-CB_HALFFILTERLEN;

 /* do filtering */
 pos=&tmpbuf[sFilt];
 memset(pos, 0, k*sizeof(float));
 for (i=0; i<k; i++) {
 pp=&tempbuff2[memInd+i+CB_HALFFILTERLEN];
 pp1=&cbfiltersTbl[CB_FILTERLEN-1];
 for (j=0; j<CB_FILTERLEN; j++) {
 (*pos)+=(*pp++)*(*pp1--);
 }
 pos++;
 }

 ihigh=k/2;
 ilow=ihigh-5;

 /* Copy first noninterpolated part */

 memcpy(cbvec, tmpbuf+lMem-k/2,
 ilow*sizeof(float));

 /* interpolation */

 alfa1=(float)0.2;
 alfa=0.0;
 for (j=ilow; j<ihigh; j++) {
 cbvec[j]=((float)1.0-alfa)*
 tmpbuf[lMem-k/2+j]+alfa*tmpbuf[lMem-k+j];
 alfa+=alfa1;
 }






 /* Copy second noninterpolated part */

 memcpy(cbvec+ihigh, tmpbuf+lMem-k+ihigh,
 (cbveclen-ihigh)*sizeof(float));
 }
 }
 }