27319718b1f8/code-docs/ZeroCrossing_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.
     Copyright 2006 Chris Cannam.

     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 "ZeroCrossing.h"

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

 #include <cmath>
 #include <algorithm>

 ZeroCrossing::ZeroCrossing(float inputSampleRate) :
     Plugin(inputSampleRate),
     m_stepSize(0),
     m_previousSample(0.0f)
 {
 }

 ZeroCrossing::~ZeroCrossing()
 {
 }

 string
 ZeroCrossing::getIdentifier() const
 {
     return "zerocrossing";
 }

 string
 ZeroCrossing::getName() const
 {
     return "Zero Crossings";
 }

 string
 ZeroCrossing::getDescription() const
 {
     return "Detect and count zero crossing points";
 }

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

 int
 ZeroCrossing::getPluginVersion() const
 {
     return 2;
 }

 string
 ZeroCrossing::getCopyright() const
 {
     return "Freely redistributable (BSD license)";
 }

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

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

     return true;
 }

 void
 ZeroCrossing::reset()
 {
     m_previousSample = 0.0f;
 }

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

     OutputDescriptor zc;
     zc.identifier = "counts";
     zc.name = "Zero Crossing Counts";
     zc.description = "The number of zero crossing points per processing block";
     zc.unit = "crossings";
     zc.hasFixedBinCount = true;
     zc.binCount = 1;
     zc.hasKnownExtents = false;
     zc.isQuantized = true;
     zc.quantizeStep = 1.0;
     zc.sampleType = OutputDescriptor::OneSamplePerStep;
     list.push_back(zc);

     zc.identifier = "zerocrossings";
     zc.name = "Zero Crossings";
     zc.description = "The locations of zero crossing points";
     zc.unit = "";
     zc.hasFixedBinCount = true;
     zc.binCount = 0;
     zc.sampleType = OutputDescriptor::VariableSampleRate;
     zc.sampleRate = m_inputSampleRate;
     list.push_back(zc);

     return list;
 }

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

     float prev = m_previousSample;
     size_t count = 0;

     FeatureSet returnFeatures;

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

         float sample = inputBuffers[0][i];
         bool crossing = false;

         if (sample <= 0.0) {
             if (prev > 0.0) crossing = true;
         } else if (sample > 0.0) {
             if (prev <= 0.0) crossing = true;
         }

         if (crossing) {
             ++count;
             Feature feature;
             feature.hasTimestamp = true;
             feature.timestamp = timestamp +
                 Vamp::RealTime::frame2RealTime(i, (size_t)m_inputSampleRate);
             returnFeatures[1].push_back(feature);
         }

         prev = sample;
     }

     m_previousSample = prev;

     Feature feature;
     feature.hasTimestamp = false;
     feature.values.push_back(float(count));

     returnFeatures[0].push_back(feature);
     return returnFeatures;
 }

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

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

Chris@6: ZeroCrossing::process
FeatureSet process(const float *const *inputBuffers, Vamp::RealTime timestamp)
Process a single block of input data.
Definition: ZeroCrossing.cpp:143

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

Chris@6: Vamp::Plugin::OutputDescriptor::sampleRate
float sampleRate
Sample rate of the output results, as samples per second.
Definition: vamp-sdk/Plugin.h:314

Chris@6: ZeroCrossing::getOutputDescriptors
OutputList getOutputDescriptors() const
Get the outputs of this plugin.
Definition: ZeroCrossing.cpp:112

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: ZeroCrossing::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: ZeroCrossing.cpp:95

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

Chris@6: ZeroCrossing::m_stepSize
size_t m_stepSize
Definition: ZeroCrossing.h:73

Chris@6: Vamp::Plugin::OutputDescriptor::quantizeStep
float quantizeStep
Quantization resolution of the output values (e.g.
Definition: vamp-sdk/Plugin.h:285

Chris@6: ZeroCrossing::getRemainingFeatures
FeatureSet getRemainingFeatures()
After all blocks have been processed, calculate and return any remaining features derived from the co...
Definition: ZeroCrossing.cpp:192

Chris@6: Vamp::Plugin::Feature::timestamp
RealTime timestamp
Timestamp of the output feature.
Definition: vamp-sdk/Plugin.h:360

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: ZeroCrossing::reset
void reset()
Reset the plugin after use, to prepare it for another clean run.
Definition: ZeroCrossing.cpp:106

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: 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: ZeroCrossing::getIdentifier
std::string getIdentifier() const
Get the computer-usable name of the plugin.
Definition: ZeroCrossing.cpp:59

Chris@6: ZeroCrossing::~ZeroCrossing
virtual ~ZeroCrossing()
Definition: ZeroCrossing.cpp:54

Chris@6: ZeroCrossing::ZeroCrossing
ZeroCrossing(float inputSampleRate)
Definition: ZeroCrossing.cpp:47

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: ZeroCrossing.h

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: ZeroCrossing::getPluginVersion
int getPluginVersion() const
Get the version number of the plugin.
Definition: ZeroCrossing.cpp:83

Chris@6: ZeroCrossing::getMaker
std::string getMaker() const
Get the name of the author or vendor of the plugin in human-readable form.
Definition: ZeroCrossing.cpp:77

Chris@6: Vamp::RealTime::frame2RealTime
static RealTime frame2RealTime(long frame, unsigned int sampleRate)
Convert a sample frame at the given sample rate into a RealTime.

Chris@6: ZeroCrossing::getCopyright
std::string getCopyright() const
Get the copyright statement or licensing summary for the plugin.
Definition: ZeroCrossing.cpp:89

Chris@6: ZeroCrossing::getName
std::string getName() const
Get a human-readable name or title of the plugin.
Definition: ZeroCrossing.cpp:65

Chris@6: ZeroCrossing::getDescription
std::string getDescription() const
Get a human-readable description for the plugin, typically a line of text that may optionally be disp...
Definition: ZeroCrossing.cpp:71

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: ZeroCrossing::m_previousSample
float m_previousSample
Definition: ZeroCrossing.h:74

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

Chris@6: Vamp::Plugin::OutputDescriptor::VariableSampleRate
Results are unevenly spaced and have individual timestamps.
Definition: vamp-sdk/Plugin.h:296

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: