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java.lang.ObjectjAudioFeatureExtractor.AudioFeatures.FeatureExtractor
jAudioFeatureExtractor.AudioFeatures.BeatHistogram
public class BeatHistogram
A feature extractor that extracts the Beat Histogram from a signal. This is histogram showing the strength of different rhythmic periodicities in a signal.
This is calculated by taking the RMS of 256 windows and then taking the FFT of the result.
No extracted feature values are stored in objects of this class.
IMPORTANT:
The window size of 256 RMS windows used here is hard-coded into the class BeatHistogramLabels. Any changes to the window size in this class must be made there as well.Daniel McEnnis 05-07-05 Added setElement, getElement, setElement, and clone functions
Field Summary |
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Fields inherited from class jAudioFeatureExtractor.AudioFeatures.FeatureExtractor |
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definition, dependencies, offsets, parent |
Constructor Summary | |
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BeatHistogram()
Basic constructor that sets the definition and dependencies (and their offsets) of this feature. |
Method Summary | |
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java.lang.Object |
clone()
Create an identical copy of this feature. |
double[] |
extractFeature(double[] samples,
double sampling_rate,
double[][] other_feature_values)
Extracts this feature from the given samples at the given sampling rate and given the other feature values. |
java.lang.String |
getElement(int index)
Function permitting an unintelligent outside function (ie. |
void |
setElement(int index,
java.lang.String value)
Function permitting an unintelligent outside function (i.e. |
void |
setWindowLength(int n)
Helper function to set window length for this feature. |
Methods inherited from class jAudioFeatureExtractor.AudioFeatures.FeatureExtractor |
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getDepenedencies, getDepenedencyOffsets, getFeatureDefinition, setParent, setWindow |
Methods inherited from class java.lang.Object |
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equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Constructor Detail |
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public BeatHistogram()
Method Detail |
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public double[] extractFeature(double[] samples, double sampling_rate, double[][] other_feature_values) throws java.lang.Exception
In the case of this feature the sampling_rate is ignored.
extractFeature
in class FeatureExtractor
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 index
indicates the feature/window and the second indicates the
value.
java.lang.Exception
- Throws an informative exception if the feature cannot be
calculated.public void setWindowLength(int n) throws java.lang.Exception
n
- new number of beat bins
java.lang.Exception
- thrown if the new value is less than 2public java.lang.String getElement(int index) throws java.lang.Exception
getElement
in class FeatureExtractor
index
- which of Beat Histograms's attributes should be edited.
java.lang.Exception
public void setElement(int index, java.lang.String value) throws java.lang.Exception
setElement
in class FeatureExtractor
index
- attribute to be setvalue
- new value of the attribute
java.lang.Exception
public java.lang.Object clone()
clone
in class FeatureExtractor
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