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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