1 /**
2 * Copyright (c) 2011, The University of Southampton and the individual contributors.
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without modification,
6 * are permitted provided that the following conditions are met:
7 *
8 * * Redistributions of source code must retain the above copyright notice,
9 * this list of conditions and the following disclaimer.
10 *
11 * * Redistributions in binary form must reproduce the above copyright notice,
12 * this list of conditions and the following disclaimer in the documentation
13 * and/or other materials provided with the distribution.
14 *
15 * * Neither the name of the University of Southampton nor the names of its
16 * contributors may be used to endorse or promote products derived from this
17 * software without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
21 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
22 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
23 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
24 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
25 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
26 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
28 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 */
30 /**
31 *
32 */
33 package org.openimaj.audio.features;
34
35 import java.util.Stack;
36
37 import org.openimaj.audio.AudioStream;
38
39 /**
40 * Wrapper around the jAudio implementation of Spectral flux.
41 *
42 * @author David Dupplaw (dpd@ecs.soton.ac.uk)
43 * @created 23 May 2013
44 * @version $Author$, $Revision$, $Date$
45 */
46 public class SpectralFlux extends JAudioFeatureExtractor
47 {
48 /** The mag spec processor */
49 private MagnitudeSpectrum magSpec = null;
50
51 /** The last n spectral flux values */
52 private final Stack<double[]> lastSpec = new Stack<double[]>();
53
54 /** The number of previous spectral flux to store */
55 private int numberToStore = 2;
56
57 /**
58 * Default constructor
59 */
60 public SpectralFlux()
61 {
62 this.featureExtractor = new jAudioFeatureExtractor.AudioFeatures.SpectralFlux();
63 this.magSpec = new MagnitudeSpectrum();
64 }
65
66 /**
67 * Constructor that's chainable.
68 * @param as The stream to chain to
69 */
70 public SpectralFlux( final AudioStream as )
71 {
72 super( as );
73 this.featureExtractor = new jAudioFeatureExtractor.AudioFeatures.SpectralFlux();
74 this.magSpec = new MagnitudeSpectrum();
75 }
76
77 /**
78 * {@inheritDoc}
79 * @see org.openimaj.audio.features.JAudioFeatureExtractor#getExtraInputs(double[], double)
80 */
81 @Override
82 public double[][] getExtraInputs( final double[] samples, final double sampleRate )
83 {
84 // Calculate the mag spec for this sample array
85 final double[] ms = this.magSpec.process( samples, sampleRate );
86
87 double[] ms1 = null;
88 if( this.lastSpec.size() == this.numberToStore )
89 ms1 = this.lastSpec.pop();
90 this.lastSpec.push( ms );
91
92 // System.out.println( Arrays.toString(ms) );
93 // System.out.println( Arrays.toString(ms1) );
94
95 // If we don't have 2 spectra, we return empty otherwise we return both.
96 return ms1 == null ? new double[][] {{0},{0}} : new double[][] {ms, ms1};
97 }
98
99 /**
100 * Get the number of spectral flux values to store in the feature
101 * @return the numberToStore The number to store
102 */
103 public int getNumberToStore()
104 {
105 return this.numberToStore;
106 }
107
108 /**
109 * Set the number of spectral flux values to store in the feature
110 * @param numberToStore The number of values to store
111 */
112 public void setNumberToStore( final int numberToStore )
113 {
114 this.numberToStore = numberToStore;
115 }
116 }