jAudioFeatureExtractor.AudioFeatures
Class RelativeDifferenceFunction

java.lang.Object
  extended by jAudioFeatureExtractor.AudioFeatures.FeatureExtractor
      extended by jAudioFeatureExtractor.AudioFeatures.RelativeDifferenceFunction

public class RelativeDifferenceFunction
extends FeatureExtractor

This feature calculates the log of the derivative of the RMS. This is useful for onset detection.

Author:
Daniel McEnnis

Field Summary
 
Fields inherited from class jAudioFeatureExtractor.AudioFeatures.FeatureExtractor
definition, dependencies, offsets, parent
 
Constructor Summary
RelativeDifferenceFunction()
          Basic constructor that sets the definition and dependencies (and their offsets) of this feature.
 
Method Summary
 java.lang.Object clone()
          Create an identical copy of this feature.
 double[] extractFeature(double[] samples, double sampling_rate, double[][] other_feature_values)
          Calculates the log ofthe derivative of the RMS from the last 2 versions of RMS
 
Methods inherited from class jAudioFeatureExtractor.AudioFeatures.FeatureExtractor
getDepenedencies, getDepenedencyOffsets, getElement, getFeatureDefinition, setElement, setParent, setWindow
 
Methods inherited from class java.lang.Object
equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

RelativeDifferenceFunction

public RelativeDifferenceFunction()
Basic constructor that sets the definition and dependencies (and their offsets) of this feature.

Method Detail

extractFeature

public double[] extractFeature(double[] samples,
                               double sampling_rate,
                               double[][] other_feature_values)
                        throws java.lang.Exception
Calculates the log ofthe derivative of the RMS from the last 2 versions of RMS

Specified by:
extractFeature in class FeatureExtractor
Parameters:
samples - The samples to extract the feature from.
sampling_rate - The sampling rate that the samples are encoded with.
other_feature_values - The values of other features that are needed to calculate this value. The order and offsets of these features must be the same as those returned by this class's getDependencies and getDependencyOffsets methods respectively. The first indice indicates the feature/window and the second indicates the value.
Returns:
The extracted feature value(s).
Throws:
java.lang.Exception - Throws an informative exception if the feature cannot be calculated.

clone

public java.lang.Object clone()
Create an identical copy of this feature. This permits FeatureExtractor to use the prototype pattern to create new composite features using metafeatures.

Specified by:
clone in class FeatureExtractor