static int Sound_into_MelFilter_frame (Sound me, MelFilter thee, long frame) {
autoMatrix pv = Sound_to_spectralpower (me);
double z1 = pv -> x1;
double dz = pv -> dx;
long nf = pv -> nx;
double df = thy dy;
for (long i = 1; i <= thy ny; i++) {
double p = 0;
double fc_mel = thy y1 + (i - 1) * df;
double fc_hz = MELTOHZ (fc_mel);
double fl_hz = MELTOHZ (fc_mel - df);
double fh_hz = MELTOHZ (fc_mel + df);
double *pow = pv -> z[1];
for (long j = 1; j <= nf; j++) {
// Filter with a triangular filter the power (=amplitude-squared)
double f = z1 + (j - 1) * dz;
double a = NUMtriangularfilter_amplitude (fl_hz, fc_hz, fh_hz, f);
p += a * pow[j] ;
}
thy z[i][frame] = p;
}
return 1;
}
void MelFilter_drawFilterFunctions (MelFilter me, Graphics g,
int toFreqScale, int fromFilter, int toFilter, double zmin, double zmax,
int dbScale, double ymin, double ymax, int garnish) {
if (! checkLimits (me, FilterBank_MEL, toFreqScale, & fromFilter, & toFilter,
& zmin, & zmax, dbScale, & ymin, & ymax)) {
return;
}
long n = 1000;
autoNUMvector<double> a (1, n);
Graphics_setInner (g);
Graphics_setWindow (g, zmin, zmax, ymin, ymax);
for (long j = fromFilter; j <= toFilter; j++) {
double df = (zmax - zmin) / (n - 1);
double fc_mel = my y1 + (j - 1) * my dy;
double fc_hz = MELTOHZ (fc_mel);
double fl_hz = MELTOHZ (fc_mel - my dy);
double fh_hz = MELTOHZ (fc_mel + my dy);
long ibegin, iend;
for (long i = 1; i <= n; i++) {
// Filterfunction: triangular on a linear frequency scale AND a linear amplitude scale.
double f = zmin + (i - 1) * df;
double z = scaleFrequency (f, toFreqScale, FilterBank_HERTZ);
if (z == NUMundefined) {
a[i] = NUMundefined;
} else {
a[i] = NUMtriangularfilter_amplitude (fl_hz, fc_hz, fh_hz, z);
if (dbScale) {
a[i] = to_dB (a[i], 10, ymin);
}
}
}
setDrawingLimits (a.peek(), n, ymin, ymax, &ibegin, &iend);
if (ibegin <= iend) {
double fmin = zmin + (ibegin - 1) * df;
double fmax = zmax - (n - iend) * df;
Graphics_function (g, a.peek(), ibegin, iend, fmin, fmax);
}
}
Graphics_unsetInner (g);
if (garnish) {
double distance = dbScale ? 10 : 1;
char32 const *ytext = dbScale ? U"Amplitude (dB)" : U"Amplitude";
Graphics_drawInnerBox (g);
Graphics_marksBottom (g, 2, 1, 1, 0);
Graphics_marksLeftEvery (g, 1, distance, 1, 1, 0);
Graphics_textLeft (g, 1, ytext);
Graphics_textBottom (g, 1, GetFreqScaleText (toFreqScale));
}
}
static double scaleFrequency (double f, int scale_from, int scale_to) {
double fhz = NUMundefined;
if (scale_from == scale_to) {
return f;
}
if (scale_from == FilterBank_HERTZ) {
fhz = f;
} else if (scale_from == FilterBank_BARK) {
fhz = BARKTOHZ (f);
} else if (scale_from == FilterBank_MEL) {
fhz = MELTOHZ (f);
}
if (scale_to == FilterBank_HERTZ || fhz == NUMundefined) {
return fhz;
}
if (scale_to == FilterBank_BARK) {
f = HZTOBARK (fhz);
} else if (scale_to == FilterBank_MEL) {
f = HZTOMEL (fhz);
} else {
return NUMundefined;
}
return f;
}
