SF_ShapedBandPass.java

/* For Copyright and License see LICENSE.txt and COPYING.txt in the root directory */
package com.nerdscentral.audio.pitch;

import java.util.ArrayList;
import java.util.List;

import com.nerdscentral.audio.core.SFSignal;
import com.nerdscentral.audio.pitch.algorithm.SFFilterGenerator;
import com.nerdscentral.audio.pitch.algorithm.SFFilterGenerator.NPoleFilterDef;
import com.nerdscentral.audio.pitch.algorithm.SFFilterGenerator.NPoleFilterDefListNode;
import com.nerdscentral.sython.Caster;
import com.nerdscentral.sython.SFPL_Operator;
import com.nerdscentral.sython.SFPL_RuntimeException;

public class SF_ShapedBandPass extends SFNPoleFilterOperator implements SFPL_Operator
{

    private static final double minDifference    = 1.0005777895;
    private static final long   serialVersionUID = 1L;

    @Override
    public String Word()
    {
        return Messages.getString("SF_ShapedBandPass.0"); //$NON-NLS-1$
    }

    @Override
    public Object Interpret(Object input) throws SFPL_RuntimeException
    {
        List<Object> l = Caster.makeBunch(input);

        SFSignal x = Caster.makeSFSignal(l.get(0));
        SFSignal frequencyAShape = Caster.makeSFSignal(l.get(1));
        SFSignal frequencyBShape = Caster.makeSFSignal(l.get(2));
        double order = Caster.makeDouble(l.get(3));
        double frequencyA = 0;
        double frequencyB = 0;
        SFSignal y = x.replicateEmpty();
        List<SFFilterGenerator.NPoleFilterDefListNode> filters = new ArrayList<>();
        int length = frequencyAShape.getLength();
        if (frequencyBShape.getLength() != length)
        {
            throw new SFPL_RuntimeException(Messages.getString("SF_ShapedBandPass.1")); //$NON-NLS-1$
        }
        if (x.getLength() != length)
        {
            throw new SFPL_RuntimeException(Messages.getString("SF_ShapedBandPass.2")); //$NON-NLS-1$
        }
        for (int index = 0; index < length; ++index)
        {
            double a = frequencyAShape.getSample(index);
            double b = frequencyBShape.getSample(index);
            double ar = a / frequencyA;
            if (ar < 1.0) ar = 1.0 / ar;
            double br = b / frequencyB;
            if (br < 1.0) br = 1.0 / br;
            if (index == 0 || ar > minDifference || br > minDifference)
            {
                // recalculate
                frequencyA = a;
                frequencyB = b;
                // System.out.println("" + a + "," + b);
                NPoleFilterDef fd = SFFilterGenerator.computeButterworthNBP(frequencyA, frequencyB, (int) order);
                NPoleFilterDefListNode node = new NPoleFilterDefListNode();
                node.setDefinition(fd);
                node.setPosition(index);
                filters.add(node);
            }
        }
        filterLoop(x, y, filters);
        return y;
    }
}