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PowerSpectrum.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 2008 QMUL.
    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 "PowerSpectrum.h"
    00038
    00039 using std::string;
    00040 using std::cerr;
    00041 using std::endl;
    00042
    00043 #include <math.h>
    00044
    00045 PowerSpectrum::PowerSpectrum(float inputSampleRate) :
    00046     Plugin(inputSampleRate),
    00047     m_blockSize(0)
    00048 {
    00049 }
    00050
    00051 PowerSpectrum::~PowerSpectrum()
    00052 {
    00053 }
    00054
    00055 string
    00056 PowerSpectrum::getIdentifier() const
    00057 {
    00058     return "powerspectrum";
    00059 }
    00060
    00061 string
    00062 PowerSpectrum::getName() const
    00063 {
    00064     return "Simple Power Spectrum";
    00065 }
    00066
    00067 string
    00068 PowerSpectrum::getDescription() const
    00069 {
    00070     return "Return the power spectrum of a signal";
    00071 }
    00072
    00073 string
    00074 PowerSpectrum::getMaker() const
    00075 {
    00076     return "Vamp SDK Example Plugins";
    00077 }
    00078
    00079 int
    00080 PowerSpectrum::getPluginVersion() const
    00081 {
    00082     return 1;
    00083 }
    00084
    00085 string
    00086 PowerSpectrum::getCopyright() const
    00087 {
    00088     return "Freely redistributable (BSD license)";
    00089 }
    00090
    00091 bool
    00092 PowerSpectrum::initialise(size_t channels, size_t stepSize, size_t blockSize)
    00093 {
    00094     if (channels < getMinChannelCount() ||
    00095         channels > getMaxChannelCount()) return false;
    00096
    00097     m_blockSize = blockSize;
    00098
    00099     return true;
    00100 }
    00101
    00102 void
    00103 PowerSpectrum::reset()
    00104 {
    00105 }
    00106
    00107 PowerSpectrum::OutputList
    00108 PowerSpectrum::getOutputDescriptors() const
    00109 {
    00110     OutputList list;
    00111
    00112     OutputDescriptor d;
    00113     d.identifier = "powerspectrum";
    00114     d.name = "Power Spectrum";
    00115     d.description = "Power values of the frequency spectrum bins calculated from the input signal";
    00116     d.unit = "";
    00117     d.hasFixedBinCount = true;
    00118     if (m_blockSize == 0) {
    00119         // Just so as not to return "1".  This is the bin count that
    00120         // would result from a block size of 1024, which is a likely
    00121         // default -- but the host should always set the block size
    00122         // before querying the bin count for certain.
    00123         d.binCount = 513;
    00124     } else {
    00125         d.binCount = m_blockSize / 2 + 1;
    00126     }
    00127     d.hasKnownExtents = false;
    00128     d.isQuantized = false;
    00129     d.sampleType = OutputDescriptor::OneSamplePerStep;
    00130     list.push_back(d);
    00131
    00132     return list;
    00133 }
    00134
    00135 PowerSpectrum::FeatureSet
    00136 PowerSpectrum::process(const float *const *inputBuffers, Vamp::RealTime timestamp)
    00137 {
    00138     FeatureSet fs;
    00139
    00140     if (m_blockSize == 0) {
    00141         cerr << "ERROR: PowerSpectrum::process: Not initialised" << endl;
    00142         return fs;
    00143     }
    00144
    00145     size_t n = m_blockSize / 2 + 1;
    00146     const float *fbuf = inputBuffers[0];
    00147
    00148     Feature feature;
    00149     feature.hasTimestamp = false;
    00150     feature.values.reserve(n); // optional
    00151
    00152     for (size_t i = 0; i < n; ++i) {
    00153
    00154         double real = fbuf[i * 2];
    00155         double imag = fbuf[i * 2 + 1];
    00156
    00157         feature.values.push_back(real * real + imag * imag);
    00158     }
    00159
    00160     fs[0].push_back(feature);
    00161
    00162     return fs;
    00163 }
    00164
    00165 PowerSpectrum::FeatureSet
    00166 PowerSpectrum::getRemainingFeatures()
    00167 {
    00168     return FeatureSet();
    00169 }
    00170