/**
* @param hh
* @param framesize
*/
public void init(double[] hh) {
// double the size of IR length next power of 2
int size = 2 << FirFilter.ldint(hh.length);
// double fft size
HHz = new double[2 * size];
for (int i = 0; i < hh.length; i++) {
HHz[2 * i] = hh[i];
}
Wz = new double[size];
FirFilter.ffw(Wz, size);
FirFilter.fft(HHz, Wz, size);
tempz = new double[2 * size];
save = new double[size / 2];
XX = new double[size];
}
/**
* performs overlap save convolution on the input signals xx
*
* @param xx input signal frame vector
* @param yy output signal frame vector
* @param hh time-domain impulse response
* @param framesize 2^n
*/
public void overlapSave(double[] xx, double[] yy) {
// prepend saved frame
System.arraycopy(save, 0, XX, 0, save.length);
System.arraycopy(xx, 0, XX, save.length, xx.length);
System.arraycopy(xx, 0, save, 0, xx.length);
// filter one frame
FirFilter.singleFir(Wz, XX, tempz, XX, HHz, xx.length);
// discard first half of output
System.arraycopy(XX, xx.length, yy, 0, xx.length);
}