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## jAudioFeatureExtractor.AudioFeatures
クラス BeatHistogram

    java.lang.Object
      jAudioFeatureExtractor.AudioFeatures.FeatureExtractor
          jAudioFeatureExtractor.AudioFeatures.BeatHistogram

    public class BeatHistogram

extends FeatureExtractor

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

作成者:
  Cory McKay

フィールドの概要

クラス jAudioFeatureExtractor.AudioFeatures.FeatureExtractor から継承されたフィールド
`definition, dependencies, offsets, parent`

コンストラクタの概要
`BeatHistogram()` Basic constructor that sets the definition and dependencies (and their offsets) of this feature.

メソッドの概要
`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.

クラス jAudioFeatureExtractor.AudioFeatures.FeatureExtractor から継承されたメソッド
`getDepenedencies, getDepenedencyOffsets, getFeatureDefinition, setParent, setWindow`

クラス java.lang.Object から継承されたメソッド
`equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

コンストラクタの詳細

### BeatHistogram

    public BeatHistogram()

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

メソッドの詳細

### extractFeature

    public double[] extractFeature(double[] samples,
                                   double sampling_rate,
                                   double[][] other_feature_values)
                            throws java.lang.Exception

  Extracts this feature from the given samples at the given sampling rate and given the other feature values.

  In the case of this feature the sampling_rate is ignored.

  定義:
    クラス `FeatureExtractor` 内の `extractFeature`
  パラメータ:
    `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.
  戻り値:
    The extracted feature value(s).
  例外:
    `java.lang.Exception` - Throws an informative exception if the feature cannot be calculated.

### setWindowLength

    public void setWindowLength(int n)
                         throws java.lang.Exception

  Helper function to set window length for this feature. Note that this feature does *not* conform to the syntax of setWindow so this feature is not affected by a global window change. This is necessary since the beat bins have a different meaning than most windowed features.

  パラメータ:
    `n` - new number of beat bins
  例外:
    `java.lang.Exception` - thrown if the new value is less than 2

### getElement

    public java.lang.String getElement(int index)
                                throws java.lang.Exception

  Function permitting an unintelligent outside function (ie. EditFeatures frame) to get the default values used to populate the table's entries. The correct index values are inferred from definition.attribute value.

  オーバーライド:
    クラス `FeatureExtractor` 内の `getElement`
  パラメータ:
    `index` - which of Beat Histograms's attributes should be edited.
  例外:
    `java.lang.Exception`

### setElement

    public void setElement(int index,
                           java.lang.String value)
                    throws java.lang.Exception

  Function permitting an unintelligent outside function (i.e. EditFeatures frame) to set the default values used to populate the table's entries. Like getElement, the correct index values are inferred from the definition.attributes value.

  オーバーライド:
    クラス `FeatureExtractor` 内の `setElement`
  パラメータ:
    `index` - attribute to be set
    `value` - new value of the attribute
  例外:
    `java.lang.Exception`

### 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.

  定義:
    クラス `FeatureExtractor` 内の `clone`

概要 | パッケージ | クラス | 階層ツリー | 非推奨 API | 索引 | ヘルプ
前のクラス 次のクラス | フレームあり フレームなし
概要: 入れ子 | フィールド | コンストラクタ | メソッド | 詳細: フィールド | コンストラクタ | メソッド