/* CloneStream: return a clone of given stream */
MixtureVector CloneStream(HMMSet *hset, StreamElem *ste, Boolean sharing)
{
int m,M;
MixtureElem *sme,*tme;
MixtureVector mv;
M = ste->nMix;
if (hset->hsKind == PLAINHS || hset->hsKind == SHAREDHS){
tme = (MixtureElem *)New(hset->hmem,M*sizeof(MixtureElem));
mv.cpdf = tme-1; sme = ste->spdf.cpdf + 1;
for (m=1; m<=M; m++,sme++,tme++){
tme->weight = sme->weight;
tme->mpdf =
(tme->weight>MINMIX)?CloneMixPDF(hset,sme->mpdf,sharing):NULL;
}
} else if (hset->hsKind == TIEDHS) {
mv.tpdf = CreateVector(hset->hmem,M);
CopyVector(ste->spdf.tpdf,mv.tpdf);
} else {
mv.dpdf = CreateShortVec(hset->hmem,M);
CopyShortVec(ste->spdf.dpdf,mv.dpdf);
}
return mv;
}
/* EXPORT->InitFBank: Initialise an FBankInfo record */
FBankInfo InitFBank(MemHeap *x, int frameSize, long sampPeriod, int numChans,
float lopass, float hipass, Boolean usePower, Boolean takeLogs,
Boolean doubleFFT,
float alpha, float warpLowCut, float warpUpCut)
{
FBankInfo fb;
float mlo,mhi,ms,melk;
int k,chan,maxChan,Nby2;
/* Save sizes to cross-check subsequent usage */
fb.frameSize = frameSize; fb.numChans = numChans;
fb.sampPeriod = sampPeriod;
fb.usePower = usePower; fb.takeLogs = takeLogs;
/* Calculate required FFT size */
fb.fftN = 2;
while (frameSize>fb.fftN) fb.fftN *= 2;
if (doubleFFT)
fb.fftN *= 2;
Nby2 = fb.fftN / 2;
fb.fres = 1.0E7/(sampPeriod * fb.fftN * 700.0);
maxChan = numChans+1;
/* set lo and hi pass cut offs if any */
fb.klo = 2; fb.khi = Nby2; /* apply lo/hi pass filtering */
mlo = 0; mhi = Mel(Nby2+1,fb.fres);
if (lopass>=0.0) {
mlo = 1127*log(1+lopass/700.0);
fb.klo = (int) ((lopass * sampPeriod * 1.0e-7 * fb.fftN) + 2.5);
if (fb.klo<2) fb.klo = 2;
}
if (hipass>=0.0) {
mhi = 1127*log(1+hipass/700.0);
fb.khi = (int) ((hipass * sampPeriod * 1.0e-7 * fb.fftN) + 0.5);
if (fb.khi>Nby2) fb.khi = Nby2;
}
if (trace&T_MEL){
printf("FFT passband %d to %d out of 1 to %d\n",fb.klo,fb.khi,Nby2);
printf("Mel passband %f to %f\n",mlo,mhi);
}
/* Create vector of fbank centre frequencies */
fb.cf = CreateVector(x,maxChan);
ms = mhi - mlo;
for (chan=1; chan <= maxChan; chan++) {
if (alpha == 1.0) {
fb.cf[chan] = ((float)chan/(float)maxChan)*ms + mlo;
}
else {
/* scale assuming scaling starts at lopass */
float minFreq = 700.0 * (exp (mlo / 1127.0) - 1.0 );
float maxFreq = 700.0 * (exp (mhi / 1127.0) - 1.0 );
float cf = ((float)chan / (float) maxChan) * ms + mlo;
cf = 700 * (exp (cf / 1127.0) - 1.0);
fb.cf[chan] = 1127.0 * log (1.0 + WarpFreq (warpLowCut, warpUpCut, cf, minFreq, maxFreq, alpha) / 700.0);
}
}
/* Create loChan map, loChan[fftindex] -> lower channel index */
fb.loChan = CreateShortVec(x,Nby2);
for (k=1,chan=1; k<=Nby2; k++){
melk = Mel(k,fb.fres);
if (k<fb.klo || k>fb.khi) fb.loChan[k]=-1;
else {
while (fb.cf[chan] < melk && chan<=maxChan) ++chan;
fb.loChan[k] = chan-1;
}
}
/* Create vector of lower channel weights */
fb.loWt = CreateVector(x,Nby2);
for (k=1; k<=Nby2; k++) {
chan = fb.loChan[k];
if (k<fb.klo || k>fb.khi) fb.loWt[k]=0.0;
else {
if (chan>0)
fb.loWt[k] = ((fb.cf[chan+1] - Mel(k,fb.fres)) /
(fb.cf[chan+1] - fb.cf[chan]));
else
fb.loWt[k] = (fb.cf[1]-Mel(k,fb.fres))/(fb.cf[1] - mlo);
}
}
/* Create workspace for fft */
fb.x = CreateVector(x,fb.fftN);
return fb;
}
