# SpectralCentroid.cpp

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    00001 /* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
    00002
    00003 /*
    00004     Vamp
    00005
    00006     An API for audio analysis and feature extraction plugins.
    00007
    00008     Centre for Digital Music, Queen Mary, University of London.
    00009     Copyright 2006 Chris Cannam.
    00010
    00011     Permission is hereby granted, free of charge, to any person
    00012     obtaining a copy of this software and associated documentation
    00013     files (the "Software"), to deal in the Software without
    00014     restriction, including without limitation the rights to use, copy,
    00015     modify, merge, publish, distribute, sublicense, and/or sell copies
    00016     of the Software, and to permit persons to whom the Software is
    00017     furnished to do so, subject to the following conditions:
    00018
    00019     The above copyright notice and this permission notice shall be
    00020     included in all copies or substantial portions of the Software.
    00021
    00022     THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
    00023     EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
    00024     MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
    00025     NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR
    00026     ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
    00027     CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
    00028     WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
    00029
    00030     Except as contained in this notice, the names of the Centre for
    00031     Digital Music; Queen Mary, University of London; and Chris Cannam
    00032     shall not be used in advertising or otherwise to promote the sale,
    00033     use or other dealings in this Software without prior written
    00034     authorization.
    00035 */
    00036
    00037 #include "SpectralCentroid.h"
    00038
    00039 using std::string;
    00040 using std::vector;
    00041 using std::cerr;
    00042 using std::endl;
    00043
    00044 #include <math.h>
    00045
    00046 #ifdef __SUNPRO_CC
    00047 #include <ieeefp.h>
    00048 #define isinf(x) (!finite(x))
    00049 #endif
    00050
    00051 #ifdef WIN32
    00052 #define isnan(x) false
    00053 #define isinf(x) false
    00054 #endif
    00055
    00056 SpectralCentroid::SpectralCentroid(float inputSampleRate) :
    00057     Plugin(inputSampleRate),
    00058     m_stepSize(0),
    00059     m_blockSize(0)
    00060 {
    00061 }
    00062
    00063 SpectralCentroid::~SpectralCentroid()
    00064 {
    00065 }
    00066
    00067 string
    00068 SpectralCentroid::getIdentifier() const
    00069 {
    00070     return "spectralcentroid";
    00071 }
    00072
    00073 string
    00074 SpectralCentroid::getName() const
    00075 {
    00076     return "Spectral Centroid";
    00077 }
    00078
    00079 string
    00080 SpectralCentroid::getDescription() const
    00081 {
    00082     return "Calculate the centroid frequency of the spectrum of the input signal";
    00083 }
    00084
    00085 string
    00086 SpectralCentroid::getMaker() const
    00087 {
    00088     return "Vamp SDK Example Plugins";
    00089 }
    00090
    00091 int
    00092 SpectralCentroid::getPluginVersion() const
    00093 {
    00094     return 2;
    00095 }
    00096
    00097 string
    00098 SpectralCentroid::getCopyright() const
    00099 {
    00100     return "Freely redistributable (BSD license)";
    00101 }
    00102
    00103 bool
    00104 SpectralCentroid::initialise(size_t channels, size_t stepSize, size_t blockSize)
    00105 {
    00106     if (channels < getMinChannelCount() ||
    00107         channels > getMaxChannelCount()) return false;
    00108
    00109     m_stepSize = stepSize;
    00110     m_blockSize = blockSize;
    00111
    00112     return true;
    00113 }
    00114
    00115 void
    00116 SpectralCentroid::reset()
    00117 {
    00118 }
    00119
    00120 SpectralCentroid::OutputList
    00121 SpectralCentroid::getOutputDescriptors() const
    00122 {
    00123     OutputList list;
    00124
    00125     OutputDescriptor d;
    00126     d.identifier = "logcentroid";
    00127     d.name = "Log Frequency Centroid";
    00128     d.description = "Centroid of the log weighted frequency spectrum";
    00129     d.unit = "Hz";
    00130     d.hasFixedBinCount = true;
    00131     d.binCount = 1;
    00132     d.hasKnownExtents = false;
    00133     d.isQuantized = false;
    00134     d.sampleType = OutputDescriptor::OneSamplePerStep;
    00135     list.push_back(d);
    00136
    00137     d.identifier = "linearcentroid";
    00138     d.name = "Linear Frequency Centroid";
    00139     d.description = "Centroid of the linear frequency spectrum";
    00140     list.push_back(d);
    00141
    00142     return list;
    00143 }
    00144
    00145 SpectralCentroid::FeatureSet
    00146 SpectralCentroid::process(const float *const *inputBuffers, Vamp::RealTime timestamp)
    00147 {
    00148     if (m_stepSize == 0) {
    00149         cerr << "ERROR: SpectralCentroid::process: "
    00150              << "SpectralCentroid has not been initialised"
    00151              << endl;
    00152         return FeatureSet();
    00153     }
    00154
    00155     double numLin = 0.0, numLog = 0.0, denom = 0.0;
    00156
    00157     for (size_t i = 1; i <= m_blockSize/2; ++i) {
    00158         double freq = (double(i) * m_inputSampleRate) / m_blockSize;
    00159         double real = inputBuffers[0][i*2];
    00160         double imag = inputBuffers[0][i*2 + 1];
    00161         double scalemag = sqrt(real * real + imag * imag) / (m_blockSize/2);
    00162         numLin += freq * scalemag;
    00163         numLog += log10f(freq) * scalemag;
    00164         denom += scalemag;
    00165     }
    00166
    00167     FeatureSet returnFeatures;
    00168
    00169     if (denom != 0.0) {
    00170         float centroidLin = float(numLin / denom);
    00171         float centroidLog = powf(10, float(numLog / denom));
    00172
    00173         Feature feature;
    00174         feature.hasTimestamp = false;
    00175
    00176         if (!isnan(centroidLog) && !isinf(centroidLog)) {
    00177             feature.values.push_back(centroidLog);
    00178         }
    00179         returnFeatures[0].push_back(feature);
    00180
    00181         feature.values.clear();
    00182         if (!isnan(centroidLin) && !isinf(centroidLin)) {
    00183             feature.values.push_back(centroidLin);
    00184         }
    00185         returnFeatures[1].push_back(feature);
    00186     }
    00187
    00188     return returnFeatures;
    00189 }
    00190
    00191 SpectralCentroid::FeatureSet
    00192 SpectralCentroid::getRemainingFeatures()
    00193 {
    00194     return FeatureSet();
    00195 }
    00196