27319718b1f8/code-docs/AmplitudeFollower_8cpp_source.html

 /* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */

 /*
     Vamp

     An API for audio analysis and feature extraction plugins.

     Centre for Digital Music, Queen Mary, University of London.
     This file copyright 2006 Dan Stowell.

     Permission is hereby granted, free of charge, to any person
     obtaining a copy of this software and associated documentation
     files (the "Software"), to deal in the Software without
     restriction, including without limitation the rights to use, copy,
     modify, merge, publish, distribute, sublicense, and/or sell copies
     of the Software, and to permit persons to whom the Software is
     furnished to do so, subject to the following conditions:

     The above copyright notice and this permission notice shall be
     included in all copies or substantial portions of the Software.

     THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
     EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
     MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
     NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR
     ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
     CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
     WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

     Except as contained in this notice, the names of the Centre for
     Digital Music; Queen Mary, University of London; and Chris Cannam
     shall not be used in advertising or otherwise to promote the sale,
     use or other dealings in this Software without prior written
     authorization.
 */

 #include "AmplitudeFollower.h"

 #include <cmath>

 #include <string>
 #include <vector>
 #include <iostream>
 #include <algorithm>

 using std::string;
 using std::vector;
 using std::cerr;
 using std::endl;

 AmplitudeFollower::AmplitudeFollower(float inputSampleRate) :
     Plugin(inputSampleRate),
     m_stepSize(0),
     m_previn(0.0f),
     m_clampcoef(0.01f),
     m_relaxcoef(0.01f)
 {
 }

 AmplitudeFollower::~AmplitudeFollower()
 {
 }

 string
 AmplitudeFollower::getIdentifier() const
 {
     return "amplitudefollower";
 }

 string
 AmplitudeFollower::getName() const
 {
     return "Amplitude Follower";
 }

 string
 AmplitudeFollower::getDescription() const
 {
     return "Track the amplitude of the audio signal";
 }

 string
 AmplitudeFollower::getMaker() const
 {
     return "Vamp SDK Example Plugins";
 }

 int
 AmplitudeFollower::getPluginVersion() const
 {
     return 1;
 }

 string
 AmplitudeFollower::getCopyright() const
 {
     return "Code copyright 2006 Dan Stowell; method from SuperCollider.  Freely redistributable (BSD license)";
 }

 bool
 AmplitudeFollower::initialise(size_t channels, size_t stepSize, size_t blockSize)
 {
     if (channels < getMinChannelCount() ||
         channels > getMaxChannelCount()) return false;

     m_stepSize = std::min(stepSize, blockSize);

     // Translate the coefficients
     // from their "convenient" 60dB convergence-time values
     // to real coefficients
     m_clampcoef = m_clampcoef==0.0 ? 0.0 : exp(log(0.1)/(m_clampcoef * m_inputSampleRate));
     m_relaxcoef = m_relaxcoef==0.0 ? 0.0 : exp(log(0.1)/(m_relaxcoef * m_inputSampleRate));

     return true;
 }

 void
 AmplitudeFollower::reset()
 {
     m_previn = 0.0f;
 }

 AmplitudeFollower::OutputList
 AmplitudeFollower::getOutputDescriptors() const
 {
     OutputList list;

     OutputDescriptor sca;
     sca.identifier = "amplitude";
     sca.name = "Amplitude";
     sca.description = "The peak tracked amplitude for the current processing block";
     sca.unit = "V";
     sca.hasFixedBinCount = true;
     sca.binCount = 1;
     sca.hasKnownExtents = false;
     sca.isQuantized = false;
     sca.sampleType = OutputDescriptor::OneSamplePerStep;
     list.push_back(sca);

     return list;
 }

 AmplitudeFollower::ParameterList
 AmplitudeFollower::getParameterDescriptors() const
 {
     ParameterList list;

     ParameterDescriptor att;
     att.identifier = "attack";
     att.name = "Attack time";
     att.description = "The 60dB convergence time for an increase in amplitude";
     att.unit = "s";
     att.minValue = 0.0f;
     att.maxValue = 1.f;
     att.defaultValue = 0.01f;
     att.isQuantized = false;

     list.push_back(att);

     ParameterDescriptor dec;
     dec.identifier = "release";
     dec.name = "Release time";
     dec.description = "The 60dB convergence time for a decrease in amplitude";
     dec.unit = "s";
     dec.minValue = 0.0f;
     dec.maxValue = 1.f;
     dec.defaultValue = 0.01f;
     dec.isQuantized = false;

     list.push_back(dec);

     return list;
 }

 void AmplitudeFollower::setParameter(std::string paramid, float newval)
 {
     if (paramid == "attack") {
         m_clampcoef = newval;
     } else if (paramid == "release") {
         m_relaxcoef = newval;
     }
 }

 float AmplitudeFollower::getParameter(std::string paramid) const
 {
     if (paramid == "attack") {
         return m_clampcoef;
     } else if (paramid == "release") {
         return m_relaxcoef;
     }

     return 0.0f;
 }

 AmplitudeFollower::FeatureSet
 AmplitudeFollower::process(const float *const *inputBuffers,
                            Vamp::RealTime /* timestamp */)
 {
     if (m_stepSize == 0) {
         cerr << "ERROR: AmplitudeFollower::process: "
              << "AmplitudeFollower has not been initialised"
              << endl;
         return FeatureSet();
     }

     float previn = m_previn;

     FeatureSet returnFeatures;

     float val;
     float peak = 0.0f;

     for (size_t i = 0; i < m_stepSize; ++i) {

         val = fabs(inputBuffers[0][i]);

         if (val < previn) {
             val = val + (previn - val) * m_relaxcoef;
         } else {
             val = val + (previn - val) * m_clampcoef;
         }

         if (val > peak) peak = val;
         previn = val;
     }

     m_previn = previn;

     // Now store the "feature" (peak amp) for this sample
     Feature feature;
     feature.hasTimestamp = false;
     feature.values.push_back(peak);
     returnFeatures[0].push_back(feature);

     return returnFeatures;
 }

 AmplitudeFollower::FeatureSet
 AmplitudeFollower::getRemainingFeatures()
 {
     return FeatureSet();
 }

Vamp::Plugin::OutputList
std::vector< OutputDescriptor > OutputList
Definition: vamp-sdk/Plugin.h:335

Chris@6: AmplitudeFollower::initialise
bool initialise(size_t channels, size_t stepSize, size_t blockSize)
Initialise a plugin to prepare it for use with the given number of input channels, step size (window increment, in sample frames) and block size (window size, in sample frames).
Definition: AmplitudeFollower.cpp:106

Chris@6: Vamp::Plugin::OutputDescriptor
Definition: vamp-sdk/Plugin.h:206

Chris@6: AmplitudeFollower::AmplitudeFollower
AmplitudeFollower(float inputSampleRate)
An implementation of SuperCollider&#39;s amplitude-follower algorithm as a simple Vamp plugin...
Definition: AmplitudeFollower.cpp:56

Chris@6: Vamp::Plugin::OutputDescriptor::hasFixedBinCount
bool hasFixedBinCount
True if the output has the same number of values per sample for every output sample.
Definition: vamp-sdk/Plugin.h:239

Chris@6: Vamp::Plugin::Feature::values
std::vector< float > values
Results for a single sample of this feature.
Definition: vamp-sdk/Plugin.h:382

Chris@6: Vamp::Plugin::FeatureSet
std::map< int, FeatureList > FeatureSet
Definition: vamp-sdk/Plugin.h:395

Chris@6: Vamp::PluginBase::ParameterDescriptor::identifier
std::string identifier
The name of the parameter, in computer-usable form.
Definition: vamp-sdk/PluginBase.h:133

Chris@6: Vamp::Plugin::OutputDescriptor::description
std::string description
A human-readable short text describing the output.
Definition: vamp-sdk/Plugin.h:227

Chris@6: Vamp::Plugin::OutputDescriptor::identifier
std::string identifier
The name of the output, in computer-usable form.
Definition: vamp-sdk/Plugin.h:214

Chris@6: AmplitudeFollower::getRemainingFeatures
FeatureSet getRemainingFeatures()
After all blocks have been processed, calculate and return any remaining features derived from the co...
Definition: AmplitudeFollower.cpp:244

Chris@6: Vamp::PluginBase::ParameterDescriptor::name
std::string name
The human-readable name of the parameter.
Definition: vamp-sdk/PluginBase.h:138

Chris@6: Vamp::Plugin::Feature
Definition: vamp-sdk/Plugin.h:344

Chris@6: Vamp::Plugin::m_inputSampleRate
float m_inputSampleRate
Definition: vamp-sdk/Plugin.h:444

Chris@6: AmplitudeFollower::getName
std::string getName() const
Get a human-readable name or title of the plugin.
Definition: AmplitudeFollower.cpp:76

Chris@6: Vamp::PluginBase::ParameterDescriptor::minValue
float minValue
The minimum value of the parameter.
Definition: vamp-sdk/PluginBase.h:154

Chris@6: Vamp::PluginBase::ParameterDescriptor::unit
std::string unit
The unit of the parameter, in human-readable form.
Definition: vamp-sdk/PluginBase.h:149

Chris@6: Vamp::Plugin::OutputDescriptor::unit
std::string unit
The unit of the output, in human-readable form.
Definition: vamp-sdk/Plugin.h:232

Chris@6: Vamp::Plugin::getMinChannelCount
virtual size_t getMinChannelCount() const
Get the minimum supported number of input channels.
Definition: vamp-sdk/Plugin.h:199

Chris@6: Vamp::Plugin::OutputDescriptor::name
std::string name
The human-readable name of the output.
Definition: vamp-sdk/Plugin.h:220

Chris@6: Vamp::Plugin::getMaxChannelCount
virtual size_t getMaxChannelCount() const
Get the maximum supported number of input channels.
Definition: vamp-sdk/Plugin.h:204

Chris@6: Vamp::RealTime
RealTime represents time values to nanosecond precision with accurate arithmetic and frame-rate conve...
Definition: vamp-sdk/RealTime.h:66

Chris@6: Vamp::Plugin::Feature::hasTimestamp
bool hasTimestamp
True if an output feature has its own timestamp.
Definition: vamp-sdk/Plugin.h:352

Chris@6: AmplitudeFollower::getMaker
std::string getMaker() const
Get the name of the author or vendor of the plugin in human-readable form.
Definition: AmplitudeFollower.cpp:88

Chris@6: AmplitudeFollower.h

Chris@6: Vamp::PluginBase::ParameterDescriptor::description
std::string description
A human-readable short text describing the parameter.
Definition: vamp-sdk/PluginBase.h:144

Chris@6: Vamp::PluginBase::ParameterDescriptor
Definition: vamp-sdk/PluginBase.h:126

Chris@6: Vamp::PluginBase::ParameterDescriptor::maxValue
float maxValue
The maximum value of the parameter.
Definition: vamp-sdk/PluginBase.h:159

Chris@6: AmplitudeFollower::reset
void reset()
Reset the plugin after use, to prepare it for another clean run.
Definition: AmplitudeFollower.cpp:123

Chris@6: AmplitudeFollower::m_stepSize
size_t m_stepSize
Definition: AmplitudeFollower.h:77

Chris@6: AmplitudeFollower::getIdentifier
std::string getIdentifier() const
Get the computer-usable name of the plugin.
Definition: AmplitudeFollower.cpp:70

Chris@6: AmplitudeFollower::m_previn
float m_previn
Definition: AmplitudeFollower.h:78

Chris@6: AmplitudeFollower::getCopyright
std::string getCopyright() const
Get the copyright statement or licensing summary for the plugin.
Definition: AmplitudeFollower.cpp:100

Chris@6: AmplitudeFollower::getOutputDescriptors
OutputList getOutputDescriptors() const
Get the outputs of this plugin.
Definition: AmplitudeFollower.cpp:129

Chris@6: Vamp::Plugin::OutputDescriptor::OneSamplePerStep
Results from each process() align with that call&#39;s block start.
Definition: vamp-sdk/Plugin.h:290

Chris@6: Vamp::Plugin::OutputDescriptor::binCount
size_t binCount
The number of values per result of the output.
Definition: vamp-sdk/Plugin.h:247

Chris@6: AmplitudeFollower::getParameterDescriptors
ParameterList getParameterDescriptors() const
Get the controllable parameters of this plugin.
Definition: AmplitudeFollower.cpp:149

Chris@6: AmplitudeFollower::getParameter
float getParameter(std::string paramid) const
Get the value of a named parameter.
Definition: AmplitudeFollower.cpp:189

Chris@6: AmplitudeFollower::m_clampcoef
float m_clampcoef
Definition: AmplitudeFollower.h:79

Chris@6: Vamp::Plugin::OutputDescriptor::isQuantized
bool isQuantized
True if the output values are quantized to a particular resolution.
Definition: vamp-sdk/Plugin.h:278

Chris@6: AmplitudeFollower::m_relaxcoef
float m_relaxcoef
Definition: AmplitudeFollower.h:80

Chris@6: Vamp::PluginBase::ParameterDescriptor::defaultValue
float defaultValue
The default value of the parameter.
Definition: vamp-sdk/PluginBase.h:167

Chris@6: AmplitudeFollower::setParameter
void setParameter(std::string paramid, float newval)
Set a named parameter.
Definition: AmplitudeFollower.cpp:180

Chris@6: AmplitudeFollower::getPluginVersion
int getPluginVersion() const
Get the version number of the plugin.
Definition: AmplitudeFollower.cpp:94

Chris@6: AmplitudeFollower::getDescription
std::string getDescription() const
Get a human-readable description for the plugin, typically a line of text that may optionally be disp...
Definition: AmplitudeFollower.cpp:82

Chris@6: AmplitudeFollower::process
FeatureSet process(const float *const *inputBuffers, Vamp::RealTime timestamp)
Process a single block of input data.
Definition: AmplitudeFollower.cpp:201

Chris@6: Vamp::PluginBase::ParameterDescriptor::isQuantized
bool isQuantized
True if the parameter values are quantized to a particular resolution.
Definition: vamp-sdk/PluginBase.h:173

Chris@6: AmplitudeFollower::~AmplitudeFollower
virtual ~AmplitudeFollower()
Definition: AmplitudeFollower.cpp:65

Chris@6: Vamp::Plugin::OutputDescriptor::sampleType
SampleType sampleType
Positioning in time of the output results.
Definition: vamp-sdk/Plugin.h:302

Chris@6: Vamp::Plugin::OutputDescriptor::hasKnownExtents
bool hasKnownExtents
True if the results in each output bin fall within a fixed numeric range (minimum and maximum values)...
Definition: vamp-sdk/Plugin.h:260

Chris@6: Vamp::PluginBase::ParameterList
std::vector< ParameterDescriptor > ParameterList
Definition: vamp-sdk/PluginBase.h:203

Chris@6: