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 org.openimaj.audio.AudioStream;
36 import org.openimaj.audio.samples.SampleBuffer;
37
38 /**
39 * A wrapper around the MFCC implementation of jAudio (which itself
40 * is a wrapper around the OrangeCow Volume implementation of FFT).
41 *
42 * @author David Dupplaw (dpd@ecs.soton.ac.uk)
43 * @created 5 Mar 2013
44 * @version $Author$, $Revision$, $Date$
45 */
46 public class MFCC extends JAudioFeatureExtractor
47 {
48 /** Processor for magnitude spectrum */
49 private MagnitudeSpectrum magSpec = null;
50
51 /**
52 * Default constructor
53 */
54 public MFCC()
55 {
56 this.featureExtractor = new jAudioFeatureExtractor.AudioFeatures.MFCC();
57 this.magSpec = new MagnitudeSpectrum();
58 }
59
60 /**
61 * Constructor for chaining to a stream
62 * @param as The audio stream
63 */
64 public MFCC( final AudioStream as )
65 {
66 super( as );
67 this.featureExtractor = new jAudioFeatureExtractor.AudioFeatures.MFCC();
68 this.magSpec = new MagnitudeSpectrum();
69 }
70
71 /**
72 * Calculate the MFCCs for the given sample buffer.
73 * @param sb The sample buffer
74 * @return The MFCCs
75 */
76 public double[][] calculateMFCC( final SampleBuffer sb )
77 {
78 this.process( sb );
79 return this.getLastCalculatedFeature();
80 }
81
82 /**
83 * {@inheritDoc}
84 * @see org.openimaj.audio.features.JAudioFeatureExtractor#getExtraInputs(double[], double)
85 */
86 @Override
87 public double[][] getExtraInputs( final double[] samples, final double sampleRate )
88 {
89 return new double[][] { this.magSpec.process( samples, sampleRate ) };
90 }
91
92 /**
93 * Returns the MFCCs with the first coefficient set to zero.
94 * @return The MFCCs with the first set to zero.
95 */
96 public double[][] getLastCalculatedFeatureWithoutFirst()
97 {
98 final double[][] d = this.getLastCalculatedFeature();
99 for( final double[] dd : d )
100 dd[0] = 0;
101 return d;
102 }
103 }