Formant LPC_to_Formant (LPC me, double margin) {
try {
double samplingFrequency = 1.0 / my samplingPeriod;
long nmax = my maxnCoefficients, err = 0;
long interval = nmax > 20 ? 1 : 10;
if (nmax > 99) {
Melder_throw ("We cannot find the roots of a polynomial of order > 99.");
}
if (margin >= samplingFrequency / 4) {
Melder_throw ("Margin must be smaller than ", samplingFrequency / 4, ".");
}
autoFormant thee = Formant_create (my xmin, my xmax, my nx, my dx, my x1, (nmax + 1) / 2);
autoMelderProgress progress (L"LPC to Formant");
for (long i = 1; i <= my nx; i++) {
Formant_Frame formant = & thy d_frames[i];
LPC_Frame lpc = & my d_frames[i];
// Initialisation of Formant_Frame is taken care of in Roots_into_Formant_Frame!
try {
LPC_Frame_into_Formant_Frame (lpc, formant, my samplingPeriod, margin);
} catch (MelderError) {
Melder_clearError();
err++;
}
if ( (interval == 1 || (i % interval) == 1)) {
Melder_progress ( (double) i / my nx, L"LPC to Formant: frame ", Melder_integer (i),
L" out of ", Melder_integer (my nx), L".");
}
}
Formant_sort (thee.peek());
if (err > 0) {
Melder_warning (Melder_integer (err), L" formant frames out of ", Melder_integer (my nx), L" suspect.");
}
return thee.transfer();
} catch (MelderError) {
Melder_throw (me, ": no Formant created.");
}
}
static autoFormant Sound_to_Formant_any_inline (Sound me, double dt_in, int numberOfPoles,
double halfdt_window, int which, double preemphasisFrequency, double safetyMargin)
{
double dt = dt_in > 0.0 ? dt_in : halfdt_window / 4.0;
double duration = my nx * my dx, t1;
double dt_window = 2.0 * halfdt_window;
long nFrames = 1 + (long) floor ((duration - dt_window) / dt);
long nsamp_window = (long) floor (dt_window / my dx), halfnsamp_window = nsamp_window / 2;
if (nsamp_window < numberOfPoles + 1)
Melder_throw (U"Window too short.");
t1 = my x1 + 0.5 * (duration - my dx - (nFrames - 1) * dt); // centre of first frame
if (nFrames < 1) {
nFrames = 1;
t1 = my x1 + 0.5 * duration;
dt_window = duration;
nsamp_window = my nx;
}
autoFormant thee = Formant_create (my xmin, my xmax, nFrames, dt, t1, (numberOfPoles + 1) / 2); // e.g. 11 poles -> maximally 6 formants
autoNUMvector <double> window (1, nsamp_window);
autoNUMvector <double> frame (1, nsamp_window);
autoNUMvector <double> cof (1, numberOfPoles); // superfluous if which==2, but nobody uses that anyway
autoMelderProgress progress (U"Formant analysis...");
/* Pre-emphasis. */
Sound_preEmphasis (me, preemphasisFrequency);
/* Gaussian window. */
for (long i = 1; i <= nsamp_window; i ++) {
double imid = 0.5 * (nsamp_window + 1), edge = exp (-12.0);
window [i] = (exp (-48.0 * (i - imid) * (i - imid) / (nsamp_window + 1) / (nsamp_window + 1)) - edge) / (1.0 - edge);
}
for (long iframe = 1; iframe <= nFrames; iframe ++) {
double t = Sampled_indexToX (thee.peek(), iframe);
long leftSample = Sampled_xToLowIndex (me, t);
long rightSample = leftSample + 1;
long startSample = rightSample - halfnsamp_window;
long endSample = leftSample + halfnsamp_window;
double maximumIntensity = 0.0;
if (startSample < 1) startSample = 1;
if (endSample > my nx) endSample = my nx;
for (long i = startSample; i <= endSample; i ++) {
double value = Sampled_getValueAtSample (me, i, Sound_LEVEL_MONO, 0);
if (value * value > maximumIntensity) {
maximumIntensity = value * value;
}
}
if (maximumIntensity == HUGE_VAL)
Melder_throw (U"Sound contains infinities.");
thy d_frames [iframe]. intensity = maximumIntensity;
if (maximumIntensity == 0.0) continue; // Burg cannot stand all zeroes
/* Copy a pre-emphasized window to a frame. */
for (long j = 1, i = startSample; j <= nsamp_window; j ++)
frame [j] = Sampled_getValueAtSample (me, i ++, Sound_LEVEL_MONO, 0) * window [j];
if (which == 1) {
burg (frame.peek(), endSample - startSample + 1, cof.peek(), numberOfPoles, & thy d_frames [iframe], 0.5 / my dx, safetyMargin);
} else if (which == 2) {
if (! splitLevinson (frame.peek(), endSample - startSample + 1, numberOfPoles, & thy d_frames [iframe], 0.5 / my dx)) {
Melder_clearError ();
Melder_casual (U"(Sound_to_Formant:)"
U" Analysis results of frame ", iframe,
U" will be wrong."
);
}
}
Melder_progress ((double) iframe / (double) nFrames, U"Formant analysis: frame ", iframe);
}
Formant_sort (thee.peek());
return thee;
}