public float[] map(final float[] data) {
final float[] out = new float[data.length * upFactor / downFactor];
for (int i = 0; i < data.length; i++) {
final float sample = data[i];
for (int j = 0; j < upFactor; j++) {
final Filters.FIRFilter filter = filters[j];
filter.addToDelayLine(sample);
final int upsampledIndex = i * upFactor + j;
if (upsampledIndex % downFactor == 0) {
out[upsampledIndex / downFactor] = (float) filter.filter();
}
}
}
return out;
}
public float[] map(final float[] data) {
final int outLength = data.length * factor;
if (out == null || out.length != outLength) {
out = new float[outLength];
} else {
Arrays.fill(out, 0);
}
for (int i = 0; i < data.length; i++) {
final float sample = data[i];
for (int j = 0; j < factor; j++) {
final Filters.FIRFilter filter = filters[j];
filter.addToDelayLine(sample);
out[i * factor + j] = (float) filter.filter();
}
}
return out;
}
/**
* Creates a decimator with the given FIR (low pass) filter.
*
* @param filter FIR filter
* @param factor nth frame to keep (factor)
*/
public Decimator(final Filters.FIRFilter filter, final int factor) {
super(filter.getCoefficients());
this.factor = factor;
}
@Override
public void reset() {
super.reset();
pos = 0;
}
/**
* Creates a resampler using a FIR low pass filter and the given up- and down-sample factors.
* The filter must be appropriate for the given factors. Internally the up- and down-factors are
* divided by their greatest common divisor to increase efficiency.
*
* @param filter FIR filter
* @param upFactor upsample factor
* @param downFactor downsample factor
*/
public Resampler(final Filters.FIRFilter filter, final int upFactor, final int downFactor) {
this(filter.getCoefficients(), upFactor, downFactor);
}
/**
* Creates an interpolator with the given FIR filter for filtering after upsampling to avoid
* aliasing. It's recommended to use a filter with a multiple of the upsample factor as the
* number of coefficients (taps). If that's not the case, zeros are added to the filter's
* coefficients.
*
* @param filter FIR filter
* @param factor upsample factor
*/
public Interpolator(final Filters.FIRFilter filter, final int factor) {
this(filter.getCoefficients(), factor);
}
