3c430ef1ed66/code-docs/ZeroCrossing_8cpp_source.html

00001 /* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
Chris@1: 00002
Chris@1: 00003 /*
Chris@1: 00004     Vamp
Chris@1: 00005
Chris@1: 00006     An API for audio analysis and feature extraction plugins.
Chris@1: 00007
Chris@1: 00008     Centre for Digital Music, Queen Mary, University of London.
Chris@1: 00009     Copyright 2006 Chris Cannam.
Chris@1: 00010
Chris@1: 00011     Permission is hereby granted, free of charge, to any person
Chris@1: 00012     obtaining a copy of this software and associated documentation
Chris@1: 00013     files (the "Software"), to deal in the Software without
Chris@1: 00014     restriction, including without limitation the rights to use, copy,
Chris@1: 00015     modify, merge, publish, distribute, sublicense, and/or sell copies
Chris@1: 00016     of the Software, and to permit persons to whom the Software is
Chris@1: 00017     furnished to do so, subject to the following conditions:
Chris@1: 00018
Chris@1: 00019     The above copyright notice and this permission notice shall be
Chris@1: 00020     included in all copies or substantial portions of the Software.
Chris@1: 00021
Chris@1: 00022     THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
Chris@1: 00023     EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
Chris@1: 00024     MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
Chris@1: 00025     NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR
Chris@1: 00026     ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
Chris@1: 00027     CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
Chris@1: 00028     WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
Chris@1: 00029
Chris@1: 00030     Except as contained in this notice, the names of the Centre for
Chris@1: 00031     Digital Music; Queen Mary, University of London; and Chris Cannam
Chris@1: 00032     shall not be used in advertising or otherwise to promote the sale,
Chris@1: 00033     use or other dealings in this Software without prior written
Chris@1: 00034     authorization.
Chris@1: 00035 */
Chris@1: 00036
Chris@1: 00037 #include "ZeroCrossing.h"
Chris@1: 00038
Chris@1: 00039 using std::string;
Chris@1: 00040 using std::vector;
Chris@1: 00041 using std::cerr;
Chris@1: 00042 using std::endl;
Chris@1: 00043
Chris@1: 00044 #include <cmath>
Chris@1: 00045
Chris@1: 00046 ZeroCrossing::ZeroCrossing(float inputSampleRate) :
Chris@1: 00047     Plugin(inputSampleRate),
Chris@1: 00048     m_stepSize(0),
Chris@1: 00049     m_previousSample(0.0f)
Chris@1: 00050 {
Chris@1: 00051 }
Chris@1: 00052
Chris@1: 00053 ZeroCrossing::~ZeroCrossing()
Chris@1: 00054 {
Chris@1: 00055 }
Chris@1: 00056
Chris@1: 00057 string
Chris@1: 00058 ZeroCrossing::getIdentifier() const
Chris@1: 00059 {
Chris@1: 00060     return "zerocrossing";
Chris@1: 00061 }
Chris@1: 00062
Chris@1: 00063 string
Chris@1: 00064 ZeroCrossing::getName() const
Chris@1: 00065 {
Chris@1: 00066     return "Zero Crossings";
Chris@1: 00067 }
Chris@1: 00068
Chris@1: 00069 string
Chris@1: 00070 ZeroCrossing::getDescription() const
Chris@1: 00071 {
Chris@1: 00072     return "Detect and count zero crossing points";
Chris@1: 00073 }
Chris@1: 00074
Chris@1: 00075 string
Chris@1: 00076 ZeroCrossing::getMaker() const
Chris@1: 00077 {
Chris@1: 00078     return "Vamp SDK Example Plugins";
Chris@1: 00079 }
Chris@1: 00080
Chris@1: 00081 int
Chris@1: 00082 ZeroCrossing::getPluginVersion() const
Chris@1: 00083 {
Chris@1: 00084     return 2;
Chris@1: 00085 }
Chris@1: 00086
Chris@1: 00087 string
Chris@1: 00088 ZeroCrossing::getCopyright() const
Chris@1: 00089 {
Chris@1: 00090     return "Freely redistributable (BSD license)";
Chris@1: 00091 }
Chris@1: 00092
Chris@1: 00093 bool
Chris@1: 00094 ZeroCrossing::initialise(size_t channels, size_t stepSize, size_t blockSize)
Chris@1: 00095 {
Chris@1: 00096     if (channels < getMinChannelCount() ||
Chris@1: 00097         channels > getMaxChannelCount()) return false;
Chris@1: 00098
Chris@1: 00099     m_stepSize = std::min(stepSize, blockSize);
Chris@1: 00100
Chris@1: 00101     return true;
Chris@1: 00102 }
Chris@1: 00103
Chris@1: 00104 void
Chris@1: 00105 ZeroCrossing::reset()
Chris@1: 00106 {
Chris@1: 00107     m_previousSample = 0.0f;
Chris@1: 00108 }
Chris@1: 00109
Chris@1: 00110 ZeroCrossing::OutputList
Chris@1: 00111 ZeroCrossing::getOutputDescriptors() const
Chris@1: 00112 {
Chris@1: 00113     OutputList list;
Chris@1: 00114
Chris@1: 00115     OutputDescriptor zc;
Chris@1: 00116     zc.identifier = "counts";
Chris@1: 00117     zc.name = "Zero Crossing Counts";
Chris@1: 00118     zc.description = "The number of zero crossing points per processing block";
Chris@1: 00119     zc.unit = "crossings";
Chris@1: 00120     zc.hasFixedBinCount = true;
Chris@1: 00121     zc.binCount = 1;
Chris@1: 00122     zc.hasKnownExtents = false;
Chris@1: 00123     zc.isQuantized = true;
Chris@1: 00124     zc.quantizeStep = 1.0;
Chris@1: 00125     zc.sampleType = OutputDescriptor::OneSamplePerStep;
Chris@1: 00126     list.push_back(zc);
Chris@1: 00127
Chris@1: 00128     zc.identifier = "zerocrossings";
Chris@1: 00129     zc.name = "Zero Crossings";
Chris@1: 00130     zc.description = "The locations of zero crossing points";
Chris@1: 00131     zc.unit = "";
Chris@1: 00132     zc.hasFixedBinCount = true;
Chris@1: 00133     zc.binCount = 0;
Chris@1: 00134     zc.sampleType = OutputDescriptor::VariableSampleRate;
Chris@1: 00135     zc.sampleRate = m_inputSampleRate;
Chris@1: 00136     list.push_back(zc);
Chris@1: 00137
Chris@1: 00138     return list;
Chris@1: 00139 }
Chris@1: 00140
Chris@1: 00141 ZeroCrossing::FeatureSet
Chris@1: 00142 ZeroCrossing::process(const float *const *inputBuffers,
Chris@1: 00143                       Vamp::RealTime timestamp)
Chris@1: 00144 {
Chris@1: 00145     if (m_stepSize == 0) {
Chris@1: 00146         cerr << "ERROR: ZeroCrossing::process: "
Chris@1: 00147              << "ZeroCrossing has not been initialised"
Chris@1: 00148              << endl;
Chris@1: 00149         return FeatureSet();
Chris@1: 00150     }
Chris@1: 00151
Chris@1: 00152     float prev = m_previousSample;
Chris@1: 00153     size_t count = 0;
Chris@1: 00154
Chris@1: 00155     FeatureSet returnFeatures;
Chris@1: 00156
Chris@1: 00157     for (size_t i = 0; i < m_stepSize; ++i) {
Chris@1: 00158
Chris@1: 00159         float sample = inputBuffers[0][i];
Chris@1: 00160         bool crossing = false;
Chris@1: 00161
Chris@1: 00162         if (sample <= 0.0) {
Chris@1: 00163             if (prev > 0.0) crossing = true;
Chris@1: 00164         } else if (sample > 0.0) {
Chris@1: 00165             if (prev <= 0.0) crossing = true;
Chris@1: 00166         }
Chris@1: 00167
Chris@1: 00168         if (crossing) {
Chris@1: 00169             ++count;
Chris@1: 00170             Feature feature;
Chris@1: 00171             feature.hasTimestamp = true;
Chris@1: 00172             feature.timestamp = timestamp +
Chris@1: 00173                 Vamp::RealTime::frame2RealTime(i, (size_t)m_inputSampleRate);
Chris@1: 00174             returnFeatures[1].push_back(feature);
Chris@1: 00175         }
Chris@1: 00176
Chris@1: 00177         prev = sample;
Chris@1: 00178     }
Chris@1: 00179
Chris@1: 00180     m_previousSample = prev;
Chris@1: 00181
Chris@1: 00182     Feature feature;
Chris@1: 00183     feature.hasTimestamp = false;
Chris@1: 00184     feature.values.push_back(float(count));
Chris@1: 00185
Chris@1: 00186     returnFeatures[0].push_back(feature);
Chris@1: 00187     return returnFeatures;
Chris@1: 00188 }
Chris@1: 00189
Chris@1: 00190 ZeroCrossing::FeatureSet
Chris@1: 00191 ZeroCrossing::getRemainingFeatures()
Chris@1: 00192 {
Chris@1: 00193     return FeatureSet();
Chris@1: 00194 }
Chris@1: 00195
Chris@1: