MFCC MelFilter_to_MFCC (MelFilter me, long numberOfCoefficients) {
try {
autoNUMmatrix<double> cosinesTable (NUMcosinesTable (my ny), 1, 1);
autoNUMvector<double> x (1, my ny);
autoNUMvector<double> y (1, my ny);
double fmax_mel = my y1 + (my ny - 1) * my dy;
numberOfCoefficients = numberOfCoefficients > my ny - 1 ? my ny - 1 : numberOfCoefficients;
Melder_assert (numberOfCoefficients > 0);
// 20130220 new interpretation of maximumNumberOfCoefficients necessary for inverse transform
autoMFCC thee = MFCC_create (my xmin, my xmax, my nx, my dx, my x1, my ny - 1, my ymin, my ymax);
for (long frame = 1; frame <= my nx; frame++) {
CC_Frame cf = (CC_Frame) & thy frame[frame];
for (long i = 1; i <= my ny; i++) {
x[i] = my z[i][frame];
}
NUMcosineTransform (x.peek(), y.peek(), my ny, cosinesTable.peek());
CC_Frame_init (cf, numberOfCoefficients);
for (long i = 1; i <= numberOfCoefficients; i++) {
cf -> c[i] = y[i + 1];
}
cf -> c0 = y[1];
}
return thee.transfer();
} catch (MelderError) {
Melder_throw (me, ": no MFCC created.");
}
}
MFCC MelFilter_to_MFCC (MelFilter me, long numberOfCoefficients) {
try {
long nf = my ny;
double fmax_mel = my y1 + (nf - 1) * my dy;
Melder_assert (numberOfCoefficients > 0);
autoNUMmatrix<double> dct (NUMcosinesTable (1, numberOfCoefficients, nf), 1, 1);
autoMFCC thee = MFCC_create (my xmin, my xmax, my nx, my dx, my x1, numberOfCoefficients, my y1, fmax_mel);
for (long frame = 1; frame <= my nx; frame++) {
CC_Frame cf = (CC_Frame) & thy frame[frame];
CC_Frame_init (cf, numberOfCoefficients);
for (long i = 1; i <= numberOfCoefficients; i++) {
double p = 0;
for (long j = 1; j <= nf; j++) {
p += my z[j][frame] * dct[i][j];
}
cf -> c[i] = p;
}
// c0 equals the average of the filterbank outputs.
double p = 0;
for (long j = 1; j <= nf; j++) {
p += my z[j][frame];
}
cf -> c0 = p / nf;
}
return thee.transfer();
} catch (MelderError) {
Melder_throw (me, ": no MFCC created.");
}
}
LFCC LPC_to_LFCC (LPC me, long numberOfCoefficients) {
try {
if (numberOfCoefficients < 1) {
numberOfCoefficients = my maxnCoefficients;
}
autoLFCC thee = LFCC_create (my xmin, my xmax, my nx, my dx, my x1,
numberOfCoefficients, 0, 0.5 / my samplingPeriod);
for (long i = 1; i <= my nx; i++) {
CC_Frame_init (& thy frame[i], numberOfCoefficients);
LPC_Frame_into_CC_Frame (& my d_frames[i], & thy frame[i]);
}
return thee.transfer();
} catch (MelderError) {
Melder_throw (me, U": no LFCC created.");
}
}
/* Precondition: 1. CC object has been created but individual frames not yet initialized
* 2. Domains and number of frames conform
* Steps:
* 1. transform power-spectra to dB-spectra
* 2. cosine transform of dB-spectrum
*/
void BandFilterSpectrogram_into_CC (BandFilterSpectrogram me, CC thee, long numberOfCoefficients) {
autoNUMmatrix<double> cosinesTable (NUMcosinesTable (my ny), 1, 1);
autoNUMvector<double> x (1, my ny);
autoNUMvector<double> y (1, my ny);
numberOfCoefficients = numberOfCoefficients > my ny - 1 ? my ny - 1 : numberOfCoefficients;
Melder_assert (numberOfCoefficients > 0);
// 20130220 new interpretation of maximumNumberOfCoefficients necessary for inverse transform
for (long frame = 1; frame <= my nx; frame++) {
CC_Frame ccframe = (CC_Frame) & thy frame[frame];
for (long i = 1; i <= my ny; i++) {
x[i] = my v_getValueAtSample (frame, i, 1); // z[i][frame];
}
NUMcosineTransform (x.peek(), y.peek(), my ny, cosinesTable.peek());
CC_Frame_init (ccframe, numberOfCoefficients);
for (long i = 1; i <= numberOfCoefficients; i++) {
ccframe -> c[i] = y[i + 1];
}
ccframe -> c0 = y[1];
}
}
