ZeroCrossing.cpp
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/* -*- 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
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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,
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*/
#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
ZeroCrossing::process
FeatureSet process(const float *const *inputBuffers, Vamp::RealTime timestamp)
Process a single block of input data.
Definition: ZeroCrossing.cpp:143
Vamp::Plugin::OutputDescriptor
Definition: vamp-sdk/Plugin.h:206
Vamp::Plugin::OutputDescriptor::sampleRate
float sampleRate
Sample rate of the output results, as samples per second.
Definition: vamp-sdk/Plugin.h:314
ZeroCrossing::getOutputDescriptors
OutputList getOutputDescriptors() const
Get the outputs of this plugin.
Definition: ZeroCrossing.cpp:112
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
Vamp::Plugin::Feature::values
std::vector< float > values
Results for a single sample of this feature.
Definition: vamp-sdk/Plugin.h:382
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
Vamp::Plugin::FeatureSet
std::map< int, FeatureList > FeatureSet
Definition: vamp-sdk/Plugin.h:395
ZeroCrossing::m_stepSize
size_t m_stepSize
Definition: ZeroCrossing.h:73
Vamp::Plugin::OutputDescriptor::quantizeStep
float quantizeStep
Quantization resolution of the output values (e.g.
Definition: vamp-sdk/Plugin.h:285
ZeroCrossing::getRemainingFeatures
FeatureSet getRemainingFeatures()
After all blocks have been processed, calculate and return any remaining features derived from the co...
Definition: ZeroCrossing.cpp:192
Vamp::Plugin::Feature::timestamp
RealTime timestamp
Timestamp of the output feature.
Definition: vamp-sdk/Plugin.h:360
Vamp::Plugin::OutputDescriptor::description
std::string description
A human-readable short text describing the output.
Definition: vamp-sdk/Plugin.h:227
ZeroCrossing::reset
void reset()
Reset the plugin after use, to prepare it for another clean run.
Definition: ZeroCrossing.cpp:106
Vamp::Plugin::OutputDescriptor::identifier
std::string identifier
The name of the output, in computer-usable form.
Definition: vamp-sdk/Plugin.h:214
Vamp::Plugin::Feature
Definition: vamp-sdk/Plugin.h:344
Vamp::Plugin::m_inputSampleRate
float m_inputSampleRate
Definition: vamp-sdk/Plugin.h:444
ZeroCrossing::getIdentifier
std::string getIdentifier() const
Get the computer-usable name of the plugin.
Definition: ZeroCrossing.cpp:59
ZeroCrossing::~ZeroCrossing
virtual ~ZeroCrossing()
Definition: ZeroCrossing.cpp:54
ZeroCrossing::ZeroCrossing
ZeroCrossing(float inputSampleRate)
Definition: ZeroCrossing.cpp:47
Vamp::Plugin::OutputDescriptor::unit
std::string unit
The unit of the output, in human-readable form.
Definition: vamp-sdk/Plugin.h:232
Vamp::Plugin::getMinChannelCount
virtual size_t getMinChannelCount() const
Get the minimum supported number of input channels.
Definition: vamp-sdk/Plugin.h:199
Vamp::Plugin::OutputDescriptor::name
std::string name
The human-readable name of the output.
Definition: vamp-sdk/Plugin.h:220
ZeroCrossing.h
Vamp::Plugin::getMaxChannelCount
virtual size_t getMaxChannelCount() const
Get the maximum supported number of input channels.
Definition: vamp-sdk/Plugin.h:204
Vamp::RealTime
RealTime represents time values to nanosecond precision with accurate arithmetic and frame-rate conve...
Definition: vamp-sdk/RealTime.h:66
Vamp::Plugin::Feature::hasTimestamp
bool hasTimestamp
True if an output feature has its own timestamp.
Definition: vamp-sdk/Plugin.h:352
ZeroCrossing::getPluginVersion
int getPluginVersion() const
Get the version number of the plugin.
Definition: ZeroCrossing.cpp:83
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
Vamp::RealTime::frame2RealTime
static RealTime frame2RealTime(long frame, unsigned int sampleRate)
Convert a sample frame at the given sample rate into a RealTime.
ZeroCrossing::getCopyright
std::string getCopyright() const
Get the copyright statement or licensing summary for the plugin.
Definition: ZeroCrossing.cpp:89
ZeroCrossing::getName
std::string getName() const
Get a human-readable name or title of the plugin.
Definition: ZeroCrossing.cpp:65
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
Vamp::Plugin::OutputDescriptor::OneSamplePerStep
Results from each process() align with that call&#39;s block start.
Definition: vamp-sdk/Plugin.h:290
Vamp::Plugin::OutputDescriptor::binCount
size_t binCount
The number of values per result of the output.
Definition: vamp-sdk/Plugin.h:247
ZeroCrossing::m_previousSample
float m_previousSample
Definition: ZeroCrossing.h:74
Vamp::Plugin::OutputDescriptor::isQuantized
bool isQuantized
True if the output values are quantized to a particular resolution.
Definition: vamp-sdk/Plugin.h:278
Vamp::Plugin::OutputDescriptor::sampleType
SampleType sampleType
Positioning in time of the output results.
Definition: vamp-sdk/Plugin.h:302
Vamp::Plugin::OutputDescriptor::VariableSampleRate
Results are unevenly spaced and have individual timestamps.
Definition: vamp-sdk/Plugin.h:296
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