RFC 3951
Internet Low Bit Rate Codec (iLBC)
Pages: 194
Experimental
Experimental
Part 5 of 6 – Pages 109 to 152
A.15. enhancer.h
/****************************************************************** iLBC Speech Coder ANSI-C Source Code enhancer.h Copyright (C) The Internet Society (2004). All Rights Reserved.
******************************************************************/
#ifndef __ENHANCER_H
#define __ENHANCER_H
#include "iLBC_define.h"
float xCorrCoef(
float *target, /* (i) first array */
float *regressor, /* (i) second array */
int subl /* (i) dimension arrays */
);
int enhancerInterface(
float *out, /* (o) the enhanced recidual signal */
float *in, /* (i) the recidual signal to enhance */
iLBC_Dec_Inst_t *iLBCdec_inst
/* (i/o) the decoder state structure */
);
#endif
A.16. enhancer.c
/******************************************************************
iLBC Speech Coder ANSI-C Source Code
enhancer.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"
/*----------------------------------------------------------------*
* Find index in array such that the array element with said
* index is the element of said array closest to "value"
* according to the squared-error criterion
*---------------------------------------------------------------*/
void NearestNeighbor(
int *index, /* (o) index of array element closest
to value */
float *array, /* (i) data array */
float value,/* (i) value */
int arlength/* (i) dimension of data array */
){
int i;
float bestcrit,crit;
crit=array[0]-value;
bestcrit=crit*crit;
*index=0;
for (i=1; i<arlength; i++) {
crit=array[i]-value;
crit=crit*crit;
if (crit<bestcrit) {
bestcrit=crit;
*index=i;
}
}
}
/*----------------------------------------------------------------*
* compute cross correlation between sequences
*---------------------------------------------------------------*/
void mycorr1(
float* corr, /* (o) correlation of seq1 and seq2 */
float* seq1, /* (i) first sequence */
int dim1, /* (i) dimension first seq1 */
const float *seq2, /* (i) second sequence */
int dim2 /* (i) dimension seq2 */
){
int i,j;
for (i=0; i<=dim1-dim2; i++) {
corr[i]=0.0;
for (j=0; j<dim2; j++) {
corr[i] += seq1[i+j] * seq2[j];
}
}
}
/*----------------------------------------------------------------*
* upsample finite array assuming zeros outside bounds
*---------------------------------------------------------------*/
void enh_upsample(
float* useq1, /* (o) upsampled output sequence */
float* seq1,/* (i) unupsampled sequence */
int dim1, /* (i) dimension seq1 */
int hfl /* (i) polyphase filter length=2*hfl+1 */
){
float *pu,*ps;
int i,j,k,q,filterlength,hfl2;
const float *polyp[ENH_UPS0]; /* pointers to
polyphase columns */
const float *pp;
/* define pointers for filter */
filterlength=2*hfl+1;
if ( filterlength > dim1 ) {
hfl2=(int) (dim1/2);
for (j=0; j<ENH_UPS0; j++) {
polyp[j]=polyphaserTbl+j*filterlength+hfl-hfl2;
}
hfl=hfl2;
filterlength=2*hfl+1;
}
else {
for (j=0; j<ENH_UPS0; j++) {
polyp[j]=polyphaserTbl+j*filterlength;
}
}
/* filtering: filter overhangs left side of sequence */
pu=useq1;
for (i=hfl; i<filterlength; i++) {
for (j=0; j<ENH_UPS0; j++) {
*pu=0.0;
pp = polyp[j];
ps = seq1+i;
for (k=0; k<=i; k++) {
*pu += *ps-- * *pp++;
}
pu++;
}
}
/* filtering: simple convolution=inner products */
for (i=filterlength; i<dim1; i++) {
for (j=0;j<ENH_UPS0; j++){
*pu=0.0;
pp = polyp[j];
ps = seq1+i;
for (k=0; k<filterlength; k++) {
*pu += *ps-- * *pp++;
}
pu++;
}
}
/* filtering: filter overhangs right side of sequence */
for (q=1; q<=hfl; q++) {
for (j=0; j<ENH_UPS0; j++) {
*pu=0.0;
pp = polyp[j]+q;
ps = seq1+dim1-1;
for (k=0; k<filterlength-q; k++) {
*pu += *ps-- * *pp++;
}
pu++;
}
}
}
/*----------------------------------------------------------------*
* find segment starting near idata+estSegPos that has highest
* correlation with idata+centerStartPos through
* idata+centerStartPos+ENH_BLOCKL-1 segment is found at a
* resolution of ENH_UPSO times the original of the original
* sampling rate
*---------------------------------------------------------------*/
void refiner(
float *seg, /* (o) segment array */
float *updStartPos, /* (o) updated start point */
float* idata, /* (i) original data buffer */
int idatal, /* (i) dimension of idata */
int centerStartPos, /* (i) beginning center segment */
float estSegPos,/* (i) estimated beginning other segment */
float period /* (i) estimated pitch period */
){
int estSegPosRounded,searchSegStartPos,searchSegEndPos,corrdim;
int tloc,tloc2,i,st,en,fraction;
float vect[ENH_VECTL],corrVec[ENH_CORRDIM],maxv;
float corrVecUps[ENH_CORRDIM*ENH_UPS0];
/* defining array bounds */
estSegPosRounded=(int)(estSegPos - 0.5);
searchSegStartPos=estSegPosRounded-ENH_SLOP;
if (searchSegStartPos<0) {
searchSegStartPos=0;
}
searchSegEndPos=estSegPosRounded+ENH_SLOP;
if (searchSegEndPos+ENH_BLOCKL >= idatal) {
searchSegEndPos=idatal-ENH_BLOCKL-1;
}
corrdim=searchSegEndPos-searchSegStartPos+1;
/* compute upsampled correlation (corr33) and find
location of max */
mycorr1(corrVec,idata+searchSegStartPos,
corrdim+ENH_BLOCKL-1,idata+centerStartPos,ENH_BLOCKL);
enh_upsample(corrVecUps,corrVec,corrdim,ENH_FL0);
tloc=0; maxv=corrVecUps[0];
for (i=1; i<ENH_UPS0*corrdim; i++) {
if (corrVecUps[i]>maxv) {
tloc=i;
maxv=corrVecUps[i];
}
}
/* make vector can be upsampled without ever running outside
bounds */
*updStartPos= (float)searchSegStartPos +
(float)tloc/(float)ENH_UPS0+(float)1.0;
tloc2=(int)(tloc/ENH_UPS0);
if (tloc>tloc2*ENH_UPS0) {
tloc2++;
}
st=searchSegStartPos+tloc2-ENH_FL0;
if (st<0) {
memset(vect,0,-st*sizeof(float));
memcpy(&vect[-st],idata, (ENH_VECTL+st)*sizeof(float));
}
else {
en=st+ENH_VECTL;
if (en>idatal) {
memcpy(vect, &idata[st],
(ENH_VECTL-(en-idatal))*sizeof(float));
memset(&vect[ENH_VECTL-(en-idatal)], 0,
(en-idatal)*sizeof(float));
}
else {
memcpy(vect, &idata[st], ENH_VECTL*sizeof(float));
}
}
fraction=tloc2*ENH_UPS0-tloc;
/* compute the segment (this is actually a convolution) */
mycorr1(seg,vect,ENH_VECTL,polyphaserTbl+(2*ENH_FL0+1)*fraction,
2*ENH_FL0+1);
}
/*----------------------------------------------------------------*
* find the smoothed output data
*---------------------------------------------------------------*/
void smath(
float *odata, /* (o) smoothed output */
float *sseq,/* (i) said second sequence of waveforms */
int hl, /* (i) 2*hl+1 is sseq dimension */
float alpha0/* (i) max smoothing energy fraction */
){
int i,k;
float w00,w10,w11,A,B,C,*psseq,err,errs;
float surround[BLOCKL_MAX]; /* shape contributed by other than
current */
float wt[2*ENH_HL+1]; /* waveform weighting to get
surround shape */
float denom;
/* create shape of contribution from all waveforms except the
current one */
for (i=1; i<=2*hl+1; i++) {
wt[i-1] = (float)0.5*(1 - (float)cos(2*PI*i/(2*hl+2)));
}
wt[hl]=0.0; /* for clarity, not used */
for (i=0; i<ENH_BLOCKL; i++) {
surround[i]=sseq[i]*wt[0];
}
for (k=1; k<hl; k++) {
psseq=sseq+k*ENH_BLOCKL;
for(i=0;i<ENH_BLOCKL; i++) {
surround[i]+=psseq[i]*wt[k];
}
}
for (k=hl+1; k<=2*hl; k++) {
psseq=sseq+k*ENH_BLOCKL;
for(i=0;i<ENH_BLOCKL; i++) {
surround[i]+=psseq[i]*wt[k];
}
}
/* compute some inner products */
w00 = w10 = w11 = 0.0;
psseq=sseq+hl*ENH_BLOCKL; /* current block */
for (i=0; i<ENH_BLOCKL;i++) {
w00+=psseq[i]*psseq[i];
w11+=surround[i]*surround[i];
w10+=surround[i]*psseq[i];
}
if (fabs(w11) < 1.0) {
w11=1.0;
}
C = (float)sqrt( w00/w11);
/* first try enhancement without power-constraint */
errs=0.0;
psseq=sseq+hl*ENH_BLOCKL;
for (i=0; i<ENH_BLOCKL; i++) {
odata[i]=C*surround[i];
err=psseq[i]-odata[i];
errs+=err*err;
}
/* if constraint violated by first try, add constraint */
if (errs > alpha0 * w00) {
if ( w00 < 1) {
w00=1;
}
denom = (w11*w00-w10*w10)/(w00*w00);
if (denom > 0.0001) { /* eliminates numerical problems
for if smooth */
A = (float)sqrt( (alpha0- alpha0*alpha0/4)/denom);
B = -alpha0/2 - A * w10/w00;
B = B+1;
}
else { /* essentially no difference between cycles;
smoothing not needed */
A= 0.0;
B= 1.0;
}
/* create smoothed sequence */
psseq=sseq+hl*ENH_BLOCKL;
for (i=0; i<ENH_BLOCKL; i++) {
odata[i]=A*surround[i]+B*psseq[i];
}
}
}
/*----------------------------------------------------------------*
* get the pitch-synchronous sample sequence
*---------------------------------------------------------------*/
void getsseq(
float *sseq, /* (o) the pitch-synchronous sequence */
float *idata, /* (i) original data */
int idatal, /* (i) dimension of data */
int centerStartPos, /* (i) where current block starts */
float *period, /* (i) rough-pitch-period array */
float *plocs, /* (i) where periods of period array
are taken */
int periodl, /* (i) dimension period array */
int hl /* (i) 2*hl+1 is the number of sequences */
){
int i,centerEndPos,q;
float blockStartPos[2*ENH_HL+1];
int lagBlock[2*ENH_HL+1];
float plocs2[ENH_PLOCSL];
float *psseq;
centerEndPos=centerStartPos+ENH_BLOCKL-1;
/* present */
NearestNeighbor(lagBlock+hl,plocs,
(float)0.5*(centerStartPos+centerEndPos),periodl);
blockStartPos[hl]=(float)centerStartPos;
psseq=sseq+ENH_BLOCKL*hl;
memcpy(psseq, idata+centerStartPos, ENH_BLOCKL*sizeof(float));
/* past */
for (q=hl-1; q>=0; q--) {
blockStartPos[q]=blockStartPos[q+1]-period[lagBlock[q+1]];
NearestNeighbor(lagBlock+q,plocs,
blockStartPos[q]+
ENH_BLOCKL_HALF-period[lagBlock[q+1]], periodl);
if (blockStartPos[q]-ENH_OVERHANG>=0) {
refiner(sseq+q*ENH_BLOCKL, blockStartPos+q, idata,
idatal, centerStartPos, blockStartPos[q],
period[lagBlock[q+1]]);
} else {
psseq=sseq+q*ENH_BLOCKL;
memset(psseq, 0, ENH_BLOCKL*sizeof(float));
}
}
/* future */
for (i=0; i<periodl; i++) {
plocs2[i]=plocs[i]-period[i];
}
for (q=hl+1; q<=2*hl; q++) {
NearestNeighbor(lagBlock+q,plocs2,
blockStartPos[q-1]+ENH_BLOCKL_HALF,periodl);
blockStartPos[q]=blockStartPos[q-1]+period[lagBlock[q]];
if (blockStartPos[q]+ENH_BLOCKL+ENH_OVERHANG<idatal) {
refiner(sseq+ENH_BLOCKL*q, blockStartPos+q, idata,
idatal, centerStartPos, blockStartPos[q],
period[lagBlock[q]]);
}
else {
psseq=sseq+q*ENH_BLOCKL;
memset(psseq, 0, ENH_BLOCKL*sizeof(float));
}
}
}
/*----------------------------------------------------------------*
* perform enhancement on idata+centerStartPos through
* idata+centerStartPos+ENH_BLOCKL-1
*---------------------------------------------------------------*/
void enhancer(
float *odata, /* (o) smoothed block, dimension blockl */
float *idata, /* (i) data buffer used for enhancing */
int idatal, /* (i) dimension idata */
int centerStartPos, /* (i) first sample current block
within idata */
float alpha0, /* (i) max correction-energy-fraction
(in [0,1]) */
float *period, /* (i) pitch period array */
float *plocs, /* (i) locations where period array
values valid */
int periodl /* (i) dimension of period and plocs */
){
float sseq[(2*ENH_HL+1)*ENH_BLOCKL];
/* get said second sequence of segments */
getsseq(sseq,idata,idatal,centerStartPos,period,
plocs,periodl,ENH_HL);
/* compute the smoothed output from said second sequence */
smath(odata,sseq,ENH_HL,alpha0);
}
/*----------------------------------------------------------------*
* cross correlation
*---------------------------------------------------------------*/
float xCorrCoef(
float *target, /* (i) first array */
float *regressor, /* (i) second array */
int subl /* (i) dimension arrays */
){
int i;
float ftmp1, ftmp2;
ftmp1 = 0.0;
ftmp2 = 0.0;
for (i=0; i<subl; i++) {
ftmp1 += target[i]*regressor[i];
ftmp2 += regressor[i]*regressor[i];
}
if (ftmp1 > 0.0) {
return (float)(ftmp1*ftmp1/ftmp2);
}
else {
return (float)0.0;
}
}
/*----------------------------------------------------------------*
* interface for enhancer
*---------------------------------------------------------------*/
int enhancerInterface(
float *out, /* (o) enhanced signal */
float *in, /* (i) unenhanced signal */
iLBC_Dec_Inst_t *iLBCdec_inst /* (i) buffers etc */
){
float *enh_buf, *enh_period;
int iblock, isample;
int lag=0, ilag, i, ioffset;
float cc, maxcc;
float ftmp1, ftmp2;
float *inPtr, *enh_bufPtr1, *enh_bufPtr2;
float plc_pred[ENH_BLOCKL];
float lpState[6], downsampled[(ENH_NBLOCKS*ENH_BLOCKL+120)/2];
int inLen=ENH_NBLOCKS*ENH_BLOCKL+120;
int start, plc_blockl, inlag;
enh_buf=iLBCdec_inst->enh_buf;
enh_period=iLBCdec_inst->enh_period;
memmove(enh_buf, &enh_buf[iLBCdec_inst->blockl],
(ENH_BUFL-iLBCdec_inst->blockl)*sizeof(float));
memcpy(&enh_buf[ENH_BUFL-iLBCdec_inst->blockl], in,
iLBCdec_inst->blockl*sizeof(float));
if (iLBCdec_inst->mode==30)
plc_blockl=ENH_BLOCKL;
else
plc_blockl=40;
/* when 20 ms frame, move processing one block */
ioffset=0;
if (iLBCdec_inst->mode==20) ioffset=1;
i=3-ioffset;
memmove(enh_period, &enh_period[i],
(ENH_NBLOCKS_TOT-i)*sizeof(float));
/* Set state information to the 6 samples right before
the samples to be downsampled. */
memcpy(lpState,
enh_buf+(ENH_NBLOCKS_EXTRA+ioffset)*ENH_BLOCKL-126,
6*sizeof(float));
/* Down sample a factor 2 to save computations */
DownSample(enh_buf+(ENH_NBLOCKS_EXTRA+ioffset)*ENH_BLOCKL-120,
lpFilt_coefsTbl, inLen-ioffset*ENH_BLOCKL,
lpState, downsampled);
/* Estimate the pitch in the down sampled domain. */
for (iblock = 0; iblock<ENH_NBLOCKS-ioffset; iblock++) {
lag = 10;
maxcc = xCorrCoef(downsampled+60+iblock*
ENH_BLOCKL_HALF, downsampled+60+iblock*
ENH_BLOCKL_HALF-lag, ENH_BLOCKL_HALF);
for (ilag=11; ilag<60; ilag++) {
cc = xCorrCoef(downsampled+60+iblock*
ENH_BLOCKL_HALF, downsampled+60+iblock*
ENH_BLOCKL_HALF-ilag, ENH_BLOCKL_HALF);
if (cc > maxcc) {
maxcc = cc;
lag = ilag;
}
}
/* Store the estimated lag in the non-downsampled domain */
enh_period[iblock+ENH_NBLOCKS_EXTRA+ioffset] = (float)lag*2;
}
/* PLC was performed on the previous packet */
if (iLBCdec_inst->prev_enh_pl==1) {
inlag=(int)enh_period[ENH_NBLOCKS_EXTRA+ioffset];
lag = inlag-1;
maxcc = xCorrCoef(in, in+lag, plc_blockl);
for (ilag=inlag; ilag<=inlag+1; ilag++) {
cc = xCorrCoef(in, in+ilag, plc_blockl);
if (cc > maxcc) {
maxcc = cc;
lag = ilag;
}
}
enh_period[ENH_NBLOCKS_EXTRA+ioffset-1]=(float)lag;
/* compute new concealed residual for the old lookahead,
mix the forward PLC with a backward PLC from
the new frame */
inPtr=&in[lag-1];
enh_bufPtr1=&plc_pred[plc_blockl-1];
if (lag>plc_blockl) {
start=plc_blockl;
} else {
start=lag;
}
for (isample = start; isample>0; isample--) {
*enh_bufPtr1-- = *inPtr--;
}
enh_bufPtr2=&enh_buf[ENH_BUFL-1-iLBCdec_inst->blockl];
for (isample = (plc_blockl-1-lag); isample>=0; isample--) {
*enh_bufPtr1-- = *enh_bufPtr2--;
}
/* limit energy change */
ftmp2=0.0;
ftmp1=0.0;
for (i=0;i<plc_blockl;i++) {
ftmp2+=enh_buf[ENH_BUFL-1-iLBCdec_inst->blockl-i]*
enh_buf[ENH_BUFL-1-iLBCdec_inst->blockl-i];
ftmp1+=plc_pred[i]*plc_pred[i];
}
ftmp1=(float)sqrt(ftmp1/(float)plc_blockl);
ftmp2=(float)sqrt(ftmp2/(float)plc_blockl);
if (ftmp1>(float)2.0*ftmp2 && ftmp1>0.0) {
for (i=0;i<plc_blockl-10;i++) {
plc_pred[i]*=(float)2.0*ftmp2/ftmp1;
}
for (i=plc_blockl-10;i<plc_blockl;i++) {
plc_pred[i]*=(float)(i-plc_blockl+10)*
((float)1.0-(float)2.0*ftmp2/ftmp1)/(float)(10)+
(float)2.0*ftmp2/ftmp1;
}
}
enh_bufPtr1=&enh_buf[ENH_BUFL-1-iLBCdec_inst->blockl];
for (i=0; i<plc_blockl; i++) {
ftmp1 = (float) (i+1) / (float) (plc_blockl+1);
*enh_bufPtr1 *= ftmp1;
*enh_bufPtr1 += ((float)1.0-ftmp1)*
plc_pred[plc_blockl-1-i];
enh_bufPtr1--;
}
}
if (iLBCdec_inst->mode==20) {
/* Enhancer with 40 samples delay */
for (iblock = 0; iblock<2; iblock++) {
enhancer(out+iblock*ENH_BLOCKL, enh_buf,
ENH_BUFL, (5+iblock)*ENH_BLOCKL+40,
ENH_ALPHA0, enh_period, enh_plocsTbl,
ENH_NBLOCKS_TOT);
}
} else if (iLBCdec_inst->mode==30) {
/* Enhancer with 80 samples delay */
for (iblock = 0; iblock<3; iblock++) {
enhancer(out+iblock*ENH_BLOCKL, enh_buf,
ENH_BUFL, (4+iblock)*ENH_BLOCKL,
ENH_ALPHA0, enh_period, enh_plocsTbl,
ENH_NBLOCKS_TOT);
}
}
return (lag*2);
}
A.17. filter.h
/******************************************************************
iLBC Speech Coder ANSI-C Source Code
filter.h
Copyright (C) The Internet Society (2004).
All Rights Reserved.
******************************************************************/
#ifndef __iLBC_FILTER_H
#define __iLBC_FILTER_H
void AllPoleFilter(
float *InOut, /* (i/o) on entrance InOut[-orderCoef] to
InOut[-1] contain the state of the
filter (delayed samples). InOut[0] to
InOut[lengthInOut-1] contain the filter
input, on en exit InOut[-orderCoef] to
InOut[-1] is unchanged and InOut[0] to
InOut[lengthInOut-1] contain filtered
samples */
float *Coef,/* (i) filter coefficients, Coef[0] is assumed
to be 1.0 */
int lengthInOut,/* (i) number of input/output samples */
int orderCoef /* (i) number of filter coefficients */
);
void AllZeroFilter(
float *In, /* (i) In[0] to In[lengthInOut-1] contain
filter input samples */
float *Coef,/* (i) filter coefficients (Coef[0] is assumed
to be 1.0) */
int lengthInOut,/* (i) number of input/output samples */
int orderCoef, /* (i) number of filter coefficients */
float *Out /* (i/o) on entrance Out[-orderCoef] to Out[-1]
contain the filter state, on exit Out[0]
to Out[lengthInOut-1] contain filtered
samples */
);
void ZeroPoleFilter(
float *In, /* (i) In[0] to In[lengthInOut-1] contain filter
input samples In[-orderCoef] to In[-1]
contain state of all-zero section */
float *ZeroCoef,/* (i) filter coefficients for all-zero
section (ZeroCoef[0] is assumed to
be 1.0) */
float *PoleCoef,/* (i) filter coefficients for all-pole section
(ZeroCoef[0] is assumed to be 1.0) */
int lengthInOut,/* (i) number of input/output samples */
int orderCoef, /* (i) number of filter coefficients */
float *Out /* (i/o) on entrance Out[-orderCoef] to Out[-1]
contain state of all-pole section. On
exit Out[0] to Out[lengthInOut-1]
contain filtered samples */
);
void DownSample (
float *In, /* (i) input samples */
float *Coef, /* (i) filter coefficients */
int lengthIn, /* (i) number of input samples */
float *state, /* (i) filter state */
float *Out /* (o) downsampled output */
);
#endif
A.18. filter.c
/******************************************************************
iLBC Speech Coder ANSI-C Source Code
filter.c
Copyright (C) The Internet Society (2004).
All Rights Reserved.
******************************************************************/
#include "iLBC_define.h"
/*----------------------------------------------------------------*
* all-pole filter
*---------------------------------------------------------------*/
void AllPoleFilter(
float *InOut, /* (i/o) on entrance InOut[-orderCoef] to
InOut[-1] contain the state of the
filter (delayed samples). InOut[0] to
InOut[lengthInOut-1] contain the filter
input, on en exit InOut[-orderCoef] to
InOut[-1] is unchanged and InOut[0] to
InOut[lengthInOut-1] contain filtered
samples */
float *Coef,/* (i) filter coefficients, Coef[0] is assumed
to be 1.0 */
int lengthInOut,/* (i) number of input/output samples */
int orderCoef /* (i) number of filter coefficients */
){
int n,k;
for(n=0;n<lengthInOut;n++){
for(k=1;k<=orderCoef;k++){
*InOut -= Coef[k]*InOut[-k];
}
InOut++;
}
}
/*----------------------------------------------------------------*
* all-zero filter
*---------------------------------------------------------------*/
void AllZeroFilter(
float *In, /* (i) In[0] to In[lengthInOut-1] contain
filter input samples */
float *Coef,/* (i) filter coefficients (Coef[0] is assumed
to be 1.0) */
int lengthInOut,/* (i) number of input/output samples */
int orderCoef, /* (i) number of filter coefficients */
float *Out /* (i/o) on entrance Out[-orderCoef] to Out[-1]
contain the filter state, on exit Out[0]
to Out[lengthInOut-1] contain filtered
samples */
){
int n,k;
for(n=0;n<lengthInOut;n++){
*Out = Coef[0]*In[0];
for(k=1;k<=orderCoef;k++){
*Out += Coef[k]*In[-k];
}
Out++;
In++;
}
}
/*----------------------------------------------------------------*
* pole-zero filter
*---------------------------------------------------------------*/
void ZeroPoleFilter(
float *In, /* (i) In[0] to In[lengthInOut-1] contain
filter input samples In[-orderCoef] to
In[-1] contain state of all-zero
section */
float *ZeroCoef,/* (i) filter coefficients for all-zero
section (ZeroCoef[0] is assumed to
be 1.0) */
float *PoleCoef,/* (i) filter coefficients for all-pole section
(ZeroCoef[0] is assumed to be 1.0) */
int lengthInOut,/* (i) number of input/output samples */
int orderCoef, /* (i) number of filter coefficients */
float *Out /* (i/o) on entrance Out[-orderCoef] to Out[-1]
contain state of all-pole section. On
exit Out[0] to Out[lengthInOut-1]
contain filtered samples */
){
AllZeroFilter(In,ZeroCoef,lengthInOut,orderCoef,Out);
AllPoleFilter(Out,PoleCoef,lengthInOut,orderCoef);
}
/*----------------------------------------------------------------*
* downsample (LP filter and decimation)
*---------------------------------------------------------------*/
void DownSample (
float *In, /* (i) input samples */
float *Coef, /* (i) filter coefficients */
int lengthIn, /* (i) number of input samples */
float *state, /* (i) filter state */
float *Out /* (o) downsampled output */
){
float o;
float *Out_ptr = Out;
float *Coef_ptr, *In_ptr;
float *state_ptr;
int i, j, stop;
/* LP filter and decimate at the same time */
for (i = DELAY_DS; i < lengthIn; i+=FACTOR_DS)
{
Coef_ptr = &Coef[0];
In_ptr = &In[i];
state_ptr = &state[FILTERORDER_DS-2];
o = (float)0.0;
stop = (i < FILTERORDER_DS) ? i + 1 : FILTERORDER_DS;
for (j = 0; j < stop; j++)
{
o += *Coef_ptr++ * (*In_ptr--);
}
for (j = i + 1; j < FILTERORDER_DS; j++)
{
o += *Coef_ptr++ * (*state_ptr--);
}
*Out_ptr++ = o;
}
/* Get the last part (use zeros as input for the future) */
for (i=(lengthIn+FACTOR_DS); i<(lengthIn+DELAY_DS);
i+=FACTOR_DS) {
o=(float)0.0;
if (i<lengthIn) {
Coef_ptr = &Coef[0];
In_ptr = &In[i];
for (j=0; j<FILTERORDER_DS; j++) {
o += *Coef_ptr++ * (*Out_ptr--);
}
} else {
Coef_ptr = &Coef[i-lengthIn];
In_ptr = &In[lengthIn-1];
for (j=0; j<FILTERORDER_DS-(i-lengthIn); j++) {
o += *Coef_ptr++ * (*In_ptr--);
}
}
*Out_ptr++ = o;
}
}
A.19. FrameClassify.h
/******************************************************************
iLBC Speech Coder ANSI-C Source Code
FrameClassify.h
Copyright (C) The Internet Society (2004).
All Rights Reserved.
******************************************************************/
#ifndef __iLBC_FRAMECLASSIFY_H
#define __iLBC_FRAMECLASSIFY_H
int FrameClassify( /* index to the max-energy sub-frame */
iLBC_Enc_Inst_t *iLBCenc_inst,
/* (i/o) the encoder state structure */
float *residual /* (i) lpc residual signal */
);
#endifA.20. FrameClassify.c
/****************************************************************** iLBC Speech Coder ANSI-C Source Code FrameClassify.c Copyright (C) The Internet Society (2004). All Rights Reserved. ******************************************************************/ #include "iLBC_define.h" /*---------------------------------------------------------------* * Classification of subframes to localize start state *--------------------------------------------------------------*/ int FrameClassify( /* index to the max-energy sub-frame */ iLBC_Enc_Inst_t *iLBCenc_inst, /* (i/o) the encoder state structure */ float *residual /* (i) lpc residual signal */ ) { float max_ssqEn, fssqEn[NSUB_MAX], bssqEn[NSUB_MAX], *pp; int n, l, max_ssqEn_n; const float ssqEn_win[NSUB_MAX-1]={(float)0.8,(float)0.9, (float)1.0,(float)0.9,(float)0.8}; const float sampEn_win[5]={(float)1.0/(float)6.0, (float)2.0/(float)6.0, (float)3.0/(float)6.0, (float)4.0/(float)6.0, (float)5.0/(float)6.0}; /* init the front and back energies to zero */ memset(fssqEn, 0, NSUB_MAX*sizeof(float)); memset(bssqEn, 0, NSUB_MAX*sizeof(float)); /* Calculate front of first seqence */ n=0; pp=residual; for (l=0; l<5; l++) { fssqEn[n] += sampEn_win[l] * (*pp) * (*pp); pp++; } for (l=5; l<SUBL; l++) {
fssqEn[n] += (*pp) * (*pp);
pp++;
}
/* Calculate front and back of all middle sequences */
for (n=1; n<iLBCenc_inst->nsub-1; n++) {
pp=residual+n*SUBL;
for (l=0; l<5; l++) {
fssqEn[n] += sampEn_win[l] * (*pp) * (*pp);
bssqEn[n] += (*pp) * (*pp);
pp++;
}
for (l=5; l<SUBL-5; l++) {
fssqEn[n] += (*pp) * (*pp);
bssqEn[n] += (*pp) * (*pp);
pp++;
}
for (l=SUBL-5; l<SUBL; l++) {
fssqEn[n] += (*pp) * (*pp);
bssqEn[n] += sampEn_win[SUBL-l-1] * (*pp) * (*pp);
pp++;
}
}
/* Calculate back of last seqence */
n=iLBCenc_inst->nsub-1;
pp=residual+n*SUBL;
for (l=0; l<SUBL-5; l++) {
bssqEn[n] += (*pp) * (*pp);
pp++;
}
for (l=SUBL-5; l<SUBL; l++) {
bssqEn[n] += sampEn_win[SUBL-l-1] * (*pp) * (*pp);
pp++;
}
/* find the index to the weighted 80 sample with
most energy */
if (iLBCenc_inst->mode==20) l=1;
else l=0;
max_ssqEn=(fssqEn[0]+bssqEn[1])*ssqEn_win[l];
max_ssqEn_n=1;
for (n=2; n<iLBCenc_inst->nsub; n++) {
l++;
if ((fssqEn[n-1]+bssqEn[n])*ssqEn_win[l] > max_ssqEn) {
max_ssqEn=(fssqEn[n-1]+bssqEn[n]) *
ssqEn_win[l];
max_ssqEn_n=n;
}
}
return max_ssqEn_n;
}
A.21. gainquant.h
/******************************************************************
iLBC Speech Coder ANSI-C Source Code
gainquant.h
Copyright (C) The Internet Society (2004).
All Rights Reserved.
******************************************************************/
#ifndef __iLBC_GAINQUANT_H
#define __iLBC_GAINQUANT_H
float gainquant(/* (o) quantized gain value */
float in, /* (i) gain value */
float maxIn,/* (i) maximum of gain value */
int cblen, /* (i) number of quantization indices */
int *index /* (o) quantization index */
);
float gaindequant( /* (o) quantized gain value */
int index, /* (i) quantization index */
float maxIn,/* (i) maximum of unquantized gain */
int cblen /* (i) number of quantization indices */
);
#endif
A.22. gainquant.c
/******************************************************************
iLBC Speech Coder ANSI-C Source Code
gainquant.c
Copyright (C) The Internet Society (2004).
All Rights Reserved.
******************************************************************/
#include <string.h>
#include <math.h>
#include "constants.h"
#include "filter.h"
/*----------------------------------------------------------------*
* quantizer for the gain in the gain-shape coding of residual
*---------------------------------------------------------------*/
float gainquant(/* (o) quantized gain value */
float in, /* (i) gain value */
float maxIn,/* (i) maximum of gain value */
int cblen, /* (i) number of quantization indices */
int *index /* (o) quantization index */
){
int i, tindex;
float minmeasure,measure, *cb, scale;
/* ensure a lower bound on the scaling factor */
scale=maxIn;
if (scale<0.1) {
scale=(float)0.1;
}
/* select the quantization table */
if (cblen == 8) {
cb = gain_sq3Tbl;
} else if (cblen == 16) {
cb = gain_sq4Tbl;
} else {
cb = gain_sq5Tbl;
}
/* select the best index in the quantization table */
minmeasure=10000000.0;
tindex=0;
for (i=0; i<cblen; i++) {
measure=(in-scale*cb[i])*(in-scale*cb[i]);
if (measure<minmeasure) {
tindex=i;
minmeasure=measure;
}
}
*index=tindex;
/* return the quantized value */
return scale*cb[tindex];
}
/*----------------------------------------------------------------*
* decoder for quantized gains in the gain-shape coding of
* residual
*---------------------------------------------------------------*/
float gaindequant( /* (o) quantized gain value */
int index, /* (i) quantization index */
float maxIn,/* (i) maximum of unquantized gain */
int cblen /* (i) number of quantization indices */
){
float scale;
/* obtain correct scale factor */
scale=(float)fabs(maxIn);
if (scale<0.1) {
scale=(float)0.1;
}
/* select the quantization table and return the decoded value */
if (cblen==8) {
return scale*gain_sq3Tbl[index];
} else if (cblen==16) {
return scale*gain_sq4Tbl[index];
}
else if (cblen==32) {
return scale*gain_sq5Tbl[index];
}
return 0.0;
}
A.23. getCBvec.h
/****************************************************************** iLBC Speech Coder ANSI-C Source Code getCBvec.h Copyright (C) The Internet Society (2004). All Rights Reserved. ******************************************************************/ #ifndef __iLBC_GETCBVEC_H #define __iLBC_GETCBVEC_H 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 */ ); #endifA.24. getCBvec.c
/****************************************************************** 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));
}
}
}
A.25. helpfun.h
/******************************************************************
iLBC Speech Coder ANSI-C Source Code
helpfun.h
Copyright (C) The Internet Society (2004).
All Rights Reserved.
******************************************************************/
#ifndef __iLBC_HELPFUN_H
#define __iLBC_HELPFUN_H
void autocorr(
float *r, /* (o) autocorrelation vector */
const float *x, /* (i) data vector */
int N, /* (i) length of data vector */
int order /* largest lag for calculated
autocorrelations */
);
void window(
float *z, /* (o) the windowed data */
const float *x, /* (i) the original data vector */
const float *y, /* (i) the window */
int N /* (i) length of all vectors */
);
void levdurb(
float *a, /* (o) lpc coefficient vector starting
with 1.0 */
float *k, /* (o) reflection coefficients */
float *r, /* (i) autocorrelation vector */
int order /* (i) order of lpc filter */
);
void interpolate(
float *out, /* (o) the interpolated vector */
float *in1, /* (i) the first vector for the
interpolation */
float *in2, /* (i) the second vector for the
interpolation */
float coef, /* (i) interpolation weights */
int length /* (i) length of all vectors */
);
void bwexpand(
float *out, /* (o) the bandwidth expanded lpc
coefficients */
float *in, /* (i) the lpc coefficients before bandwidth
expansion */
float coef, /* (i) the bandwidth expansion factor */
int length /* (i) the length of lpc coefficient vectors */
);
void vq(
float *Xq, /* (o) the quantized vector */
int *index, /* (o) the quantization index */
const float *CB,/* (i) the vector quantization codebook */
float *X, /* (i) the vector to quantize */
int n_cb, /* (i) the number of vectors in the codebook */
int dim /* (i) the dimension of all vectors */
);
void SplitVQ(
float *qX, /* (o) the quantized vector */
int *index, /* (o) a vector of indexes for all vector
codebooks in the split */
float *X, /* (i) the vector to quantize */
const float *CB,/* (i) the quantizer codebook */
int nsplit, /* the number of vector splits */
const int *dim, /* the dimension of X and qX */
const int *cbsize /* the number of vectors in the codebook */
);
void sort_sq(
float *xq, /* (o) the quantized value */
int *index, /* (o) the quantization index */
float x, /* (i) the value to quantize */
const float *cb,/* (i) the quantization codebook */
int cb_size /* (i) the size of the quantization codebook */
);
int LSF_check( /* (o) 1 for stable lsf vectors and 0 for
nonstable ones */
float *lsf, /* (i) a table of lsf vectors */
int dim, /* (i) the dimension of each lsf vector */
int NoAn /* (i) the number of lsf vectors in the
table */
);
#endif
A.26. helpfun.c
/******************************************************************
iLBC Speech Coder ANSI-C Source Code
helpfun.c
Copyright (C) The Internet Society (2004).
All Rights Reserved.
******************************************************************/
#include <math.h>
#include "iLBC_define.h"
#include "constants.h"
/*----------------------------------------------------------------*
* calculation of auto correlation
*---------------------------------------------------------------*/
void autocorr(
float *r, /* (o) autocorrelation vector */
const float *x, /* (i) data vector */
int N, /* (i) length of data vector */
int order /* largest lag for calculated
autocorrelations */
){
int lag, n;
float sum;
for (lag = 0; lag <= order; lag++) {
sum = 0;
for (n = 0; n < N - lag; n++) {
sum += x[n] * x[n+lag];
}
r[lag] = sum;
}
}
/*----------------------------------------------------------------*
* window multiplication
*---------------------------------------------------------------*/
void window(
float *z, /* (o) the windowed data */
const float *x, /* (i) the original data vector */
const float *y, /* (i) the window */
int N /* (i) length of all vectors */
){
int i;
for (i = 0; i < N; i++) {
z[i] = x[i] * y[i];
}
}
/*----------------------------------------------------------------*
* levinson-durbin solution for lpc coefficients
*---------------------------------------------------------------*/
void levdurb(
float *a, /* (o) lpc coefficient vector starting
with 1.0 */
float *k, /* (o) reflection coefficients */
float *r, /* (i) autocorrelation vector */
int order /* (i) order of lpc filter */
){
float sum, alpha;
int m, m_h, i;
a[0] = 1.0;
if (r[0] < EPS) { /* if r[0] <= 0, set LPC coeff. to zero */
for (i = 0; i < order; i++) {
k[i] = 0;
a[i+1] = 0;
}
} else {
a[1] = k[0] = -r[1]/r[0];
alpha = r[0] + r[1] * k[0];
for (m = 1; m < order; m++){
sum = r[m + 1];
for (i = 0; i < m; i++){
sum += a[i+1] * r[m - i];
}
k[m] = -sum / alpha;
alpha += k[m] * sum;
m_h = (m + 1) >> 1;
for (i = 0; i < m_h; i++){
sum = a[i+1] + k[m] * a[m - i];
a[m - i] += k[m] * a[i+1];
a[i+1] = sum;
}
a[m+1] = k[m];
}
}
}
/*----------------------------------------------------------------*
* interpolation between vectors
*---------------------------------------------------------------*/
void interpolate(
float *out, /* (o) the interpolated vector */
float *in1, /* (i) the first vector for the
interpolation */
float *in2, /* (i) the second vector for the
interpolation */
float coef, /* (i) interpolation weights */
int length /* (i) length of all vectors */
){
int i;
float invcoef;
invcoef = (float)1.0 - coef;
for (i = 0; i < length; i++) {
out[i] = coef * in1[i] + invcoef * in2[i];
}
}
/*----------------------------------------------------------------*
* lpc bandwidth expansion
*---------------------------------------------------------------*/
void bwexpand(
float *out, /* (o) the bandwidth expanded lpc
coefficients */
float *in, /* (i) the lpc coefficients before bandwidth
expansion */
float coef, /* (i) the bandwidth expansion factor */
int length /* (i) the length of lpc coefficient vectors */
){
int i;
float chirp;
chirp = coef;
out[0] = in[0];
for (i = 1; i < length; i++) {
out[i] = chirp * in[i];
chirp *= coef;
}
}
/*----------------------------------------------------------------*
* vector quantization
*---------------------------------------------------------------*/
void vq(
float *Xq, /* (o) the quantized vector */
int *index, /* (o) the quantization index */
const float *CB,/* (i) the vector quantization codebook */
float *X, /* (i) the vector to quantize */
int n_cb, /* (i) the number of vectors in the codebook */
int dim /* (i) the dimension of all vectors */
){
int i, j;
int pos, minindex;
float dist, tmp, mindist;
pos = 0;
mindist = FLOAT_MAX;
minindex = 0;
for (j = 0; j < n_cb; j++) {
dist = X[0] - CB[pos];
dist *= dist;
for (i = 1; i < dim; i++) {
tmp = X[i] - CB[pos + i];
dist += tmp*tmp;
}
if (dist < mindist) {
mindist = dist;
minindex = j;
}
pos += dim;
}
for (i = 0; i < dim; i++) {
Xq[i] = CB[minindex*dim + i];
}
*index = minindex;
}
/*----------------------------------------------------------------*
* split vector quantization
*---------------------------------------------------------------*/
void SplitVQ(
float *qX, /* (o) the quantized vector */
int *index, /* (o) a vector of indexes for all vector
codebooks in the split */
float *X, /* (i) the vector to quantize */
const float *CB,/* (i) the quantizer codebook */
int nsplit, /* the number of vector splits */
const int *dim, /* the dimension of X and qX */
const int *cbsize /* the number of vectors in the codebook */
){
int cb_pos, X_pos, i;
cb_pos = 0;
X_pos= 0;
for (i = 0; i < nsplit; i++) {
vq(qX + X_pos, index + i, CB + cb_pos, X + X_pos,
cbsize[i], dim[i]);
X_pos += dim[i];
cb_pos += dim[i] * cbsize[i];
}
}
/*----------------------------------------------------------------*
* scalar quantization
*---------------------------------------------------------------*/
void sort_sq(
float *xq, /* (o) the quantized value */
int *index, /* (o) the quantization index */
float x, /* (i) the value to quantize */
const float *cb,/* (i) the quantization codebook */
int cb_size /* (i) the size of the quantization codebook */
){
int i;
if (x <= cb[0]) {
*index = 0;
*xq = cb[0];
} else {
i = 0;
while ((x > cb[i]) && i < cb_size - 1) {
i++;
}
if (x > ((cb[i] + cb[i - 1])/2)) {
*index = i;
*xq = cb[i];
} else {
*index = i - 1;
*xq = cb[i - 1];
}
}
}
/*----------------------------------------------------------------*
* check for stability of lsf coefficients
*---------------------------------------------------------------*/
int LSF_check( /* (o) 1 for stable lsf vectors and 0 for
nonstable ones */
float *lsf, /* (i) a table of lsf vectors */
int dim, /* (i) the dimension of each lsf vector */
int NoAn /* (i) the number of lsf vectors in the
table */
){
int k,n,m, Nit=2, change=0,pos;
float tmp;
static float eps=(float)0.039; /* 50 Hz */
static float eps2=(float)0.0195;
static float maxlsf=(float)3.14; /* 4000 Hz */
static float minlsf=(float)0.01; /* 0 Hz */
/* LSF separation check*/
for (n=0; n<Nit; n++) { /* Run through a couple of times */
for (m=0; m<NoAn; m++) { /* Number of analyses per frame */
for (k=0; k<(dim-1); k++) {
pos=m*dim+k;
if ((lsf[pos+1]-lsf[pos])<eps) {
if (lsf[pos+1]<lsf[pos]) {
tmp=lsf[pos+1];
lsf[pos+1]= lsf[pos]+eps2;
lsf[pos]= lsf[pos+1]-eps2;
} else {
lsf[pos]-=eps2;
lsf[pos+1]+=eps2;
}
change=1;
}
if (lsf[pos]<minlsf) {
lsf[pos]=minlsf;
change=1;
}
if (lsf[pos]>maxlsf) {
lsf[pos]=maxlsf;
change=1;
}
}
}
}
return change;
}
A.27. hpInput.h
/******************************************************************
iLBC Speech Coder ANSI-C Source Code
hpInput.h
Copyright (C) The Internet Society (2004).
All Rights Reserved.
******************************************************************/
#ifndef __iLBC_HPINPUT_H
#define __iLBC_HPINPUT_H
void hpInput(
float *In, /* (i) vector to filter */
int len, /* (i) length of vector to filter */
float *Out, /* (o) the resulting filtered vector */
float *mem /* (i/o) the filter state */
);
#endif
A.28. hpInput.c
/******************************************************************
iLBC Speech Coder ANSI-C Source Code
hpInput.c
Copyright (C) The Internet Society (2004).
All Rights Reserved.
******************************************************************/
#include "constants.h"
/*----------------------------------------------------------------*
* Input high-pass filter
*---------------------------------------------------------------*/
void hpInput(
float *In, /* (i) vector to filter */
int len, /* (i) length of vector to filter */
float *Out, /* (o) the resulting filtered vector */
float *mem /* (i/o) the filter state */
){
int i;
float *pi, *po;
/* all-zero section*/
pi = &In[0];
po = &Out[0];
for (i=0; i<len; i++) {
*po = hpi_zero_coefsTbl[0] * (*pi);
*po += hpi_zero_coefsTbl[1] * mem[0];
*po += hpi_zero_coefsTbl[2] * mem[1];
mem[1] = mem[0];
mem[0] = *pi;
po++;
pi++;
}
/* all-pole section*/
po = &Out[0];
for (i=0; i<len; i++) {
*po -= hpi_pole_coefsTbl[1] * mem[2];
*po -= hpi_pole_coefsTbl[2] * mem[3];
mem[3] = mem[2];
mem[2] = *po;
po++;
}
}
A.29. hpOutput.h
/******************************************************************
iLBC Speech Coder ANSI-C Source Code
hpOutput.h
Copyright (C) The Internet Society (2004).
All Rights Reserved.
******************************************************************/
#ifndef __iLBC_HPOUTPUT_H
#define __iLBC_HPOUTPUT_H
void hpOutput(
float *In, /* (i) vector to filter */
int len,/* (i) length of vector to filter */
float *Out, /* (o) the resulting filtered vector */
float *mem /* (i/o) the filter state */
);
#endif
A.30. hpOutput.c
/******************************************************************
iLBC Speech Coder ANSI-C Source Code
hpOutput.c
Copyright (C) The Internet Society (2004).
All Rights Reserved.
******************************************************************/
#include "constants.h"
/*----------------------------------------------------------------*
* Output high-pass filter
*---------------------------------------------------------------*/
void hpOutput(
float *In, /* (i) vector to filter */
int len,/* (i) length of vector to filter */
float *Out, /* (o) the resulting filtered vector */
float *mem /* (i/o) the filter state */
){
int i;
float *pi, *po;
/* all-zero section*/
pi = &In[0];
po = &Out[0];
for (i=0; i<len; i++) {
*po = hpo_zero_coefsTbl[0] * (*pi);
*po += hpo_zero_coefsTbl[1] * mem[0];
*po += hpo_zero_coefsTbl[2] * mem[1];
mem[1] = mem[0];
mem[0] = *pi;
po++;
pi++;
}
/* all-pole section*/
po = &Out[0];
for (i=0; i<len; i++) {
*po -= hpo_pole_coefsTbl[1] * mem[2];
*po -= hpo_pole_coefsTbl[2] * mem[3];
mem[3] = mem[2];
mem[2] = *po;
po++;
}
}
A.31. iCBConstruct.h
/******************************************************************
iLBC Speech Coder ANSI-C Source Code
iCBConstruct.h
Copyright (C) The Internet Society (2004).
All Rights Reserved.
******************************************************************/
#ifndef __iLBC_ICBCONSTRUCT_H
#define __iLBC_ICBCONSTRUCT_H
void index_conv_enc(
int *index /* (i/o) Codebook indexes */
);
void index_conv_dec(
int *index /* (i/o) Codebook indexes */
);
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 */
);
#endif
A.32. iCBConstruct.c
/******************************************************************
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];
}
}
}
}
(page 152 continued on part 6)