AmplitudeFollower.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     This file copyright 2006 Dan Stowell.
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 "AmplitudeFollower.h"
00038 
00039 #include <cmath>
00040 
00041 #include <string>
00042 #include <vector>
00043 #include <iostream>
00044 
00045 using std::string;
00046 using std::vector;
00047 using std::cerr;
00048 using std::endl;
00049 
00055 AmplitudeFollower::AmplitudeFollower(float inputSampleRate) :
00056     Plugin(inputSampleRate),
00057     m_stepSize(0),
00058     m_previn(0.0f),
00059     m_clampcoef(0.01f),
00060     m_relaxcoef(0.01f)
00061 {
00062 }
00063 
00064 AmplitudeFollower::~AmplitudeFollower()
00065 {
00066 }
00067 
00068 string
00069 AmplitudeFollower::getIdentifier() const
00070 {
00071     return "amplitudefollower";
00072 }
00073 
00074 string
00075 AmplitudeFollower::getName() const
00076 {
00077     return "Amplitude Follower";
00078 }
00079 
00080 string
00081 AmplitudeFollower::getDescription() const
00082 {
00083     return "Track the amplitude of the audio signal";
00084 }
00085 
00086 string
00087 AmplitudeFollower::getMaker() const
00088 {
00089     return "Vamp SDK Example Plugins";
00090 }
00091 
00092 int
00093 AmplitudeFollower::getPluginVersion() const
00094 {
00095     return 1;
00096 }
00097 
00098 string
00099 AmplitudeFollower::getCopyright() const
00100 {
00101     return "Code copyright 2006 Dan Stowell; method from SuperCollider.  Freely redistributable (BSD license)";
00102 }
00103 
00104 bool
00105 AmplitudeFollower::initialise(size_t channels, size_t stepSize, size_t blockSize)
00106 {
00107     if (channels < getMinChannelCount() ||
00108         channels > getMaxChannelCount()) return false;
00109 
00110     m_stepSize = std::min(stepSize, blockSize);
00111         
00112     // Translate the coefficients 
00113     // from their "convenient" 60dB convergence-time values
00114     // to real coefficients
00115     m_clampcoef = m_clampcoef==0.0 ? 0.0 : exp(log(0.1)/(m_clampcoef * m_inputSampleRate));
00116     m_relaxcoef = m_relaxcoef==0.0 ? 0.0 : exp(log(0.1)/(m_relaxcoef * m_inputSampleRate));
00117 
00118     return true;
00119 }
00120 
00121 void
00122 AmplitudeFollower::reset()
00123 {
00124     m_previn = 0.0f;
00125 }
00126 
00127 AmplitudeFollower::OutputList
00128 AmplitudeFollower::getOutputDescriptors() const
00129 {
00130     OutputList list;
00131 
00132     OutputDescriptor sca;
00133     sca.identifier = "amplitude";
00134     sca.name = "Amplitude";
00135     sca.description = "The peak tracked amplitude for the current processing block";
00136     sca.unit = "V";
00137     sca.hasFixedBinCount = true;
00138     sca.binCount = 1;
00139     sca.hasKnownExtents = false;
00140     sca.isQuantized = false;
00141     sca.sampleType = OutputDescriptor::OneSamplePerStep;
00142     list.push_back(sca);
00143 
00144     return list;
00145 }
00146 
00147 AmplitudeFollower::ParameterList
00148 AmplitudeFollower::getParameterDescriptors() const
00149 {
00150     ParameterList list;
00151         
00152     ParameterDescriptor att;
00153     att.identifier = "attack";
00154     att.name = "Attack time";
00155     att.description = "The 60dB convergence time for an increase in amplitude";
00156     att.unit = "s";
00157     att.minValue = 0.0f;
00158     att.maxValue = 1.f;
00159     att.defaultValue = 0.01f;
00160     att.isQuantized = false;
00161     
00162     list.push_back(att);
00163     
00164     ParameterDescriptor dec;
00165     dec.identifier = "release";
00166     dec.name = "Release time";
00167     dec.description = "The 60dB convergence time for a decrease in amplitude";
00168     dec.unit = "s";
00169     dec.minValue = 0.0f;
00170     dec.maxValue = 1.f;
00171     dec.defaultValue = 0.01f;
00172     dec.isQuantized = false;
00173     
00174     list.push_back(dec);
00175     
00176     return list;
00177 }
00178 
00179 void AmplitudeFollower::setParameter(std::string paramid, float newval)
00180 {
00181     if (paramid == "attack") {
00182         m_clampcoef = newval;
00183     } else if (paramid == "release") {
00184         m_relaxcoef = newval;
00185     }
00186 }
00187 
00188 float AmplitudeFollower::getParameter(std::string paramid) const
00189 {
00190     if (paramid == "attack") {
00191         return m_clampcoef;
00192     } else if (paramid == "release") {
00193         return m_relaxcoef;
00194     }
00195 
00196     return 0.0f;
00197 }
00198 
00199 AmplitudeFollower::FeatureSet
00200 AmplitudeFollower::process(const float *const *inputBuffers,
00201                            Vamp::RealTime timestamp)
00202 {
00203     if (m_stepSize == 0) {
00204         cerr << "ERROR: AmplitudeFollower::process: "
00205              << "AmplitudeFollower has not been initialised"
00206              << endl;
00207         return FeatureSet();
00208     }
00209 
00210     float previn = m_previn;
00211 
00212     FeatureSet returnFeatures;
00213         
00214     float val;
00215     float peak = 0.0f;
00216 
00217     for (size_t i = 0; i < m_stepSize; ++i) {
00218 
00219         val = fabs(inputBuffers[0][i]);
00220                 
00221         if (val < previn) {
00222             val = val + (previn - val) * m_relaxcoef;
00223         } else {
00224             val = val + (previn - val) * m_clampcoef;
00225         }
00226 
00227         if (val > peak) peak = val;
00228         previn = val;
00229     }
00230 
00231     m_previn = previn;
00232 
00233     // Now store the "feature" (peak amp) for this sample
00234     Feature feature;
00235     feature.hasTimestamp = false;
00236     feature.values.push_back(peak);
00237     returnFeatures[0].push_back(feature);
00238 
00239     return returnFeatures;
00240 }
00241 
00242 AmplitudeFollower::FeatureSet
00243 AmplitudeFollower::getRemainingFeatures()
00244 {
00245     return FeatureSet();
00246 }
00247 

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