3c430ef1ed66/code-docs/AmplitudeFollower_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     This file copyright 2006 Dan Stowell.
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 "AmplitudeFollower.h"
Chris@1: 00038
Chris@1: 00039 #include <cmath>
Chris@1: 00040
Chris@1: 00041 #include <string>
Chris@1: 00042 #include <vector>
Chris@1: 00043 #include <iostream>
Chris@1: 00044
Chris@1: 00045 using std::string;
Chris@1: 00046 using std::vector;
Chris@1: 00047 using std::cerr;
Chris@1: 00048 using std::endl;
Chris@1: 00049
Chris@1: 00055 AmplitudeFollower::AmplitudeFollower(float inputSampleRate) :
Chris@1: 00056     Plugin(inputSampleRate),
Chris@1: 00057     m_stepSize(0),
Chris@1: 00058     m_previn(0.0f),
Chris@1: 00059     m_clampcoef(0.01f),
Chris@1: 00060     m_relaxcoef(0.01f)
Chris@1: 00061 {
Chris@1: 00062 }
Chris@1: 00063
Chris@1: 00064 AmplitudeFollower::~AmplitudeFollower()
Chris@1: 00065 {
Chris@1: 00066 }
Chris@1: 00067
Chris@1: 00068 string
Chris@1: 00069 AmplitudeFollower::getIdentifier() const
Chris@1: 00070 {
Chris@1: 00071     return "amplitudefollower";
Chris@1: 00072 }
Chris@1: 00073
Chris@1: 00074 string
Chris@1: 00075 AmplitudeFollower::getName() const
Chris@1: 00076 {
Chris@1: 00077     return "Amplitude Follower";
Chris@1: 00078 }
Chris@1: 00079
Chris@1: 00080 string
Chris@1: 00081 AmplitudeFollower::getDescription() const
Chris@1: 00082 {
Chris@1: 00083     return "Track the amplitude of the audio signal";
Chris@1: 00084 }
Chris@1: 00085
Chris@1: 00086 string
Chris@1: 00087 AmplitudeFollower::getMaker() const
Chris@1: 00088 {
Chris@1: 00089     return "Vamp SDK Example Plugins";
Chris@1: 00090 }
Chris@1: 00091
Chris@1: 00092 int
Chris@1: 00093 AmplitudeFollower::getPluginVersion() const
Chris@1: 00094 {
Chris@1: 00095     return 1;
Chris@1: 00096 }
Chris@1: 00097
Chris@1: 00098 string
Chris@1: 00099 AmplitudeFollower::getCopyright() const
Chris@1: 00100 {
Chris@1: 00101     return "Code copyright 2006 Dan Stowell; method from SuperCollider.  Freely redistributable (BSD license)";
Chris@1: 00102 }
Chris@1: 00103
Chris@1: 00104 bool
Chris@1: 00105 AmplitudeFollower::initialise(size_t channels, size_t stepSize, size_t blockSize)
Chris@1: 00106 {
Chris@1: 00107     if (channels < getMinChannelCount() ||
Chris@1: 00108         channels > getMaxChannelCount()) return false;
Chris@1: 00109
Chris@1: 00110     m_stepSize = std::min(stepSize, blockSize);
Chris@1: 00111
Chris@1: 00112     // Translate the coefficients
Chris@1: 00113     // from their "convenient" 60dB convergence-time values
Chris@1: 00114     // to real coefficients
Chris@1: 00115     m_clampcoef = m_clampcoef==0.0 ? 0.0 : exp(log(0.1)/(m_clampcoef * m_inputSampleRate));
Chris@1: 00116     m_relaxcoef = m_relaxcoef==0.0 ? 0.0 : exp(log(0.1)/(m_relaxcoef * m_inputSampleRate));
Chris@1: 00117
Chris@1: 00118     return true;
Chris@1: 00119 }
Chris@1: 00120
Chris@1: 00121 void
Chris@1: 00122 AmplitudeFollower::reset()
Chris@1: 00123 {
Chris@1: 00124     m_previn = 0.0f;
Chris@1: 00125 }
Chris@1: 00126
Chris@1: 00127 AmplitudeFollower::OutputList
Chris@1: 00128 AmplitudeFollower::getOutputDescriptors() const
Chris@1: 00129 {
Chris@1: 00130     OutputList list;
Chris@1: 00131
Chris@1: 00132     OutputDescriptor sca;
Chris@1: 00133     sca.identifier = "amplitude";
Chris@1: 00134     sca.name = "Amplitude";
Chris@1: 00135     sca.description = "The peak tracked amplitude for the current processing block";
Chris@1: 00136     sca.unit = "V";
Chris@1: 00137     sca.hasFixedBinCount = true;
Chris@1: 00138     sca.binCount = 1;
Chris@1: 00139     sca.hasKnownExtents = false;
Chris@1: 00140     sca.isQuantized = false;
Chris@1: 00141     sca.sampleType = OutputDescriptor::OneSamplePerStep;
Chris@1: 00142     list.push_back(sca);
Chris@1: 00143
Chris@1: 00144     return list;
Chris@1: 00145 }
Chris@1: 00146
Chris@1: 00147 AmplitudeFollower::ParameterList
Chris@1: 00148 AmplitudeFollower::getParameterDescriptors() const
Chris@1: 00149 {
Chris@1: 00150     ParameterList list;
Chris@1: 00151
Chris@1: 00152     ParameterDescriptor att;
Chris@1: 00153     att.identifier = "attack";
Chris@1: 00154     att.name = "Attack time";
Chris@1: 00155     att.description = "The 60dB convergence time for an increase in amplitude";
Chris@1: 00156     att.unit = "s";
Chris@1: 00157     att.minValue = 0.0f;
Chris@1: 00158     att.maxValue = 1.f;
Chris@1: 00159     att.defaultValue = 0.01f;
Chris@1: 00160     att.isQuantized = false;
Chris@1: 00161
Chris@1: 00162     list.push_back(att);
Chris@1: 00163
Chris@1: 00164     ParameterDescriptor dec;
Chris@1: 00165     dec.identifier = "release";
Chris@1: 00166     dec.name = "Release time";
Chris@1: 00167     dec.description = "The 60dB convergence time for a decrease in amplitude";
Chris@1: 00168     dec.unit = "s";
Chris@1: 00169     dec.minValue = 0.0f;
Chris@1: 00170     dec.maxValue = 1.f;
Chris@1: 00171     dec.defaultValue = 0.01f;
Chris@1: 00172     dec.isQuantized = false;
Chris@1: 00173
Chris@1: 00174     list.push_back(dec);
Chris@1: 00175
Chris@1: 00176     return list;
Chris@1: 00177 }
Chris@1: 00178
Chris@1: 00179 void AmplitudeFollower::setParameter(std::string paramid, float newval)
Chris@1: 00180 {
Chris@1: 00181     if (paramid == "attack") {
Chris@1: 00182         m_clampcoef = newval;
Chris@1: 00183     } else if (paramid == "release") {
Chris@1: 00184         m_relaxcoef = newval;
Chris@1: 00185     }
Chris@1: 00186 }
Chris@1: 00187
Chris@1: 00188 float AmplitudeFollower::getParameter(std::string paramid) const
Chris@1: 00189 {
Chris@1: 00190     if (paramid == "attack") {
Chris@1: 00191         return m_clampcoef;
Chris@1: 00192     } else if (paramid == "release") {
Chris@1: 00193         return m_relaxcoef;
Chris@1: 00194     }
Chris@1: 00195
Chris@1: 00196     return 0.0f;
Chris@1: 00197 }
Chris@1: 00198
Chris@1: 00199 AmplitudeFollower::FeatureSet
Chris@1: 00200 AmplitudeFollower::process(const float *const *inputBuffers,
Chris@1: 00201                            Vamp::RealTime timestamp)
Chris@1: 00202 {
Chris@1: 00203     if (m_stepSize == 0) {
Chris@1: 00204         cerr << "ERROR: AmplitudeFollower::process: "
Chris@1: 00205              << "AmplitudeFollower has not been initialised"
Chris@1: 00206              << endl;
Chris@1: 00207         return FeatureSet();
Chris@1: 00208     }
Chris@1: 00209
Chris@1: 00210     float previn = m_previn;
Chris@1: 00211
Chris@1: 00212     FeatureSet returnFeatures;
Chris@1: 00213
Chris@1: 00214     float val;
Chris@1: 00215     float peak = 0.0f;
Chris@1: 00216
Chris@1: 00217     for (size_t i = 0; i < m_stepSize; ++i) {
Chris@1: 00218
Chris@1: 00219         val = fabs(inputBuffers[0][i]);
Chris@1: 00220
Chris@1: 00221         if (val < previn) {
Chris@1: 00222             val = val + (previn - val) * m_relaxcoef;
Chris@1: 00223         } else {
Chris@1: 00224             val = val + (previn - val) * m_clampcoef;
Chris@1: 00225         }
Chris@1: 00226
Chris@1: 00227         if (val > peak) peak = val;
Chris@1: 00228         previn = val;
Chris@1: 00229     }
Chris@1: 00230
Chris@1: 00231     m_previn = previn;
Chris@1: 00232
Chris@1: 00233     // Now store the "feature" (peak amp) for this sample
Chris@1: 00234     Feature feature;
Chris@1: 00235     feature.hasTimestamp = false;
Chris@1: 00236     feature.values.push_back(peak);
Chris@1: 00237     returnFeatures[0].push_back(feature);
Chris@1: 00238
Chris@1: 00239     return returnFeatures;
Chris@1: 00240 }
Chris@1: 00241
Chris@1: 00242 AmplitudeFollower::FeatureSet
Chris@1: 00243 AmplitudeFollower::getRemainingFeatures()
Chris@1: 00244 {
Chris@1: 00245     return FeatureSet();
Chris@1: 00246 }
Chris@1: 00247
Chris@1: