ddf.minim.effects
Class Convolver

java.lang.Object
  ddf.minim.effects.Convolver

All Implemented Interfaces:

AudioEffect

public class Convolver
extends java.lang.Object
implements AudioEffect

Convolver is an effect that convolves a signal with a kernal. The kernal can be thought of as the impulse response of an audio filter, or simply as a set of weighting coefficients. Convolver performs brute-force convolution, meaning that it is slow, relatively speaking. However, the algorithm is very straighforward. Each output sample i is calculated by multiplying each kernal value j with the input sample i - j and then summing the resulting values. The output will be kernal.length + signal.length - 1 samples long, so the extra samples are stored in an overlap array. The overlap array from the previous signal convolution is added into the beginning of the output array, which results in a output signal without pops.

Author:

Damien Di Fede

See Also:

Convolution

Field Summary

protected float[]	kernal
protected float[]	outputL
protected float[]	outputR
protected float[]	overlapL
protected float[]	overlapR
protected int	sigLen

Constructor Summary

Convolver(float[] k, int sigLength)
Constructs a Convolver with the kernal k that expects buffer of length sigLength.

Method Summary

void	process(float[] signal) Processes signal in some way.
void	process(float[] sigLeft, float[] sigRight) Processes sigLeft and sigRight in some way.
void	setKernal(float[] k) Sets the kernal to k.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

kernal

protected float[] kernal

outputL

protected float[] outputL

overlapL

protected float[] overlapL

outputR

protected float[] outputR

overlapR

protected float[] overlapR

sigLen

protected int sigLen

Constructor Detail

Convolver

public Convolver(float[] k,
                 int sigLength)

Constructs a Convolver with the kernal k that expects buffer of length sigLength.

Parameters:

k - the kernal of the filter

sigLength - the length of the buffer that will be convolved with the kernal

Method Detail

setKernal

public void setKernal(float[] k)

Sets the kernal to k. The values in k are copied so it is not possible to alter the kernal after it has been set except by setting it again.

Parameters:

k - the kernal to use

process

public void process(float[] signal)

Description copied from interface: AudioEffect

Processes signal in some way.

Specified by:

process in interface AudioEffect

Parameters:

signal - an array of audio samples, representing a mono sound stream.

process

public void process(float[] sigLeft,
                    float[] sigRight)

Description copied from interface: AudioEffect

Processes sigLeft and sigRight in some way.

Specified by:

process in interface AudioEffect

Parameters:

sigLeft - an array of audio samples, representing the left channel of a stereo sound stream

sigRight - an array of audio samples, representing the right channel of a stereo sound stream