comparison examples/ZeroCrossing.cpp @ 0:6479539d1b32

* Importing first cut of Sonic Visualiser's Vamp plugin format SDK

+/* -*- 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 X CONSORTIUM 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;
+
+
+ZeroCrossing::ZeroCrossing(float inputSampleRate) :
+    Plugin(inputSampleRate),
+    m_stepSize(0),
+    m_previousSample(0.0f)
+{
+}
+
+ZeroCrossing::~ZeroCrossing()
+{
+}
+
+string
+ZeroCrossing::getName() const
+{
+    return "zerocrossing";
+}
+
+string
+ZeroCrossing::getDescription() const
+{
+    return "Zero Crossings";
+}
+
+string
+ZeroCrossing::getMaker() const
+{
+    return "QMUL";
+}
+
+int
+ZeroCrossing::getPluginVersion() const
+{
+    return 2;
+}
+
+string
+ZeroCrossing::getCopyright() const
+{
+    return "GPL";
+}
+
+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;
+}
+
+size_t
+ZeroCrossing::getPreferredStepSize() const
+{
+    return 4096; // or whatever
+}
+
+size_t
+ZeroCrossing::getPreferredBlockSize() const
+{
+    return getPreferredStepSize();
+}
+
+ZeroCrossing::OutputList
+ZeroCrossing::getOutputDescriptors() const
+{
+    OutputList list;
+
+    OutputDescriptor zc;
+    zc.name = "counts";
+    zc.unit = "crossings";
+    zc.description = "Zero Crossing Counts";
+    zc.hasFixedValueCount = true;
+    zc.valueCount = 1;
+    zc.hasKnownExtents = false;
+    zc.isQuantized = true;
+    zc.quantizeStep = 1.0;
+    zc.sampleType = OutputDescriptor::OneSamplePerStep;
+    list.push_back(zc);
+
+    zc.name = "zerocrossings";
+    zc.unit = "";
+    zc.description = "Zero Crossings";
+    zc.hasFixedValueCount = true;
+    zc.valueCount = 0;
+    zc.sampleType = OutputDescriptor::VariableSampleRate;
+    zc.sampleRate = m_inputSampleRate;
+    list.push_back(zc);
+
+    return list;
+}
+
+ZeroCrossing::FeatureSet
+ZeroCrossing::process(float **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(count);
+
+    returnFeatures[0].push_back(feature);
+    return returnFeatures;
+}
+
+ZeroCrossing::FeatureSet
+ZeroCrossing::getRemainingFeatures()
+{
+    return FeatureSet();
+}
+