VampPluginSDK 2.10
ZeroCrossing.cpp
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1/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*- vi:set ts=8 sts=4 sw=4: */
2
3/*
4 Vamp
5
6 An API for audio analysis and feature extraction plugins.
7
8 Centre for Digital Music, Queen Mary, University of London.
9 Copyright 2006 Chris Cannam.
10
11 Permission is hereby granted, free of charge, to any person
12 obtaining a copy of this software and associated documentation
13 files (the "Software"), to deal in the Software without
14 restriction, including without limitation the rights to use, copy,
15 modify, merge, publish, distribute, sublicense, and/or sell copies
16 of the Software, and to permit persons to whom the Software is
17 furnished to do so, subject to the following conditions:
18
19 The above copyright notice and this permission notice shall be
20 included in all copies or substantial portions of the Software.
21
22 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
23 EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
24 MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
25 NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR
26 ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
27 CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
28 WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
29
30 Except as contained in this notice, the names of the Centre for
31 Digital Music; Queen Mary, University of London; and Chris Cannam
32 shall not be used in advertising or otherwise to promote the sale,
33 use or other dealings in this Software without prior written
34 authorization.
35*/
36
37#include "ZeroCrossing.h"
38
39using std::string;
40using std::vector;
41using std::cerr;
42using std::endl;
43
44#include <cmath>
45#include <algorithm>
46
47ZeroCrossing::ZeroCrossing(float inputSampleRate) :
48 Plugin(inputSampleRate),
49 m_stepSize(0),
50 m_previousSample(0.0f)
51{
52}
53
55{
56}
57
58string
60{
61 return "zerocrossing";
62}
63
64string
66{
67 return "Zero Crossings";
68}
69
70string
72{
73 return "Detect and count zero crossing points";
74}
75
76string
78{
79 return "Vamp SDK Example Plugins";
80}
81
82int
84{
85 return 2;
86}
87
88string
90{
91 return "Freely redistributable (BSD license)";
92}
93
94bool
95ZeroCrossing::initialise(size_t channels, size_t stepSize, size_t blockSize)
96{
97 if (channels < getMinChannelCount() ||
98 channels > getMaxChannelCount()) return false;
99
100 m_stepSize = std::min(stepSize, blockSize);
101
102 return true;
103}
104
105void
107{
108 m_previousSample = 0.0f;
109}
110
113{
114 OutputList list;
115
117 zc.identifier = "counts";
118 zc.name = "Zero Crossing Counts";
119 zc.description = "The number of zero crossing points per processing block";
120 zc.unit = "crossings";
121 zc.hasFixedBinCount = true;
122 zc.binCount = 1;
123 zc.hasKnownExtents = false;
124 zc.isQuantized = true;
125 zc.quantizeStep = 1.0;
126 zc.sampleType = OutputDescriptor::OneSamplePerStep;
127 list.push_back(zc);
128
129 zc.identifier = "zerocrossings";
130 zc.name = "Zero Crossings";
131 zc.description = "The locations of zero crossing points";
132 zc.unit = "";
133 zc.hasFixedBinCount = true;
134 zc.binCount = 0;
135 zc.sampleType = OutputDescriptor::VariableSampleRate;
137 list.push_back(zc);
138
139 return list;
140}
141
143ZeroCrossing::process(const float *const *inputBuffers,
144 Vamp::RealTime timestamp)
145{
146 if (m_stepSize == 0) {
147 cerr << "ERROR: ZeroCrossing::process: "
148 << "ZeroCrossing has not been initialised"
149 << endl;
150 return FeatureSet();
151 }
152
153 float prev = m_previousSample;
154 size_t count = 0;
155
156 FeatureSet returnFeatures;
157
158 for (size_t i = 0; i < m_stepSize; ++i) {
159
160 float sample = inputBuffers[0][i];
161 bool crossing = false;
162
163 if (sample <= 0.0) {
164 if (prev > 0.0) crossing = true;
165 } else if (sample > 0.0) {
166 if (prev <= 0.0) crossing = true;
167 }
168
169 if (crossing) {
170 ++count;
171 Feature feature;
172 feature.hasTimestamp = true;
173 feature.timestamp = timestamp +
175 returnFeatures[1].push_back(feature);
176 }
177
178 prev = sample;
179 }
180
181 m_previousSample = prev;
182
183 Feature feature;
184 feature.hasTimestamp = false;
185 feature.values.push_back(float(count));
186
187 returnFeatures[0].push_back(feature);
188 return returnFeatures;
189}
190
193{
194 return FeatureSet();
195}
196
virtual size_t getMaxChannelCount() const
Get the maximum supported number of input channels.
std::vector< OutputDescriptor > OutputList
std::map< int, FeatureList > FeatureSet
float m_inputSampleRate
virtual size_t getMinChannelCount() const
Get the minimum supported number of input channels.
float m_previousSample
Definition: ZeroCrossing.h:74
std::string getName() const
Get a human-readable name or title of the plugin.
int getPluginVersion() const
Get the version number of the plugin.
size_t m_stepSize
Definition: ZeroCrossing.h:73
FeatureSet getRemainingFeatures()
After all blocks have been processed, calculate and return any remaining features derived from the co...
std::string getDescription() const
Get a human-readable description for the plugin, typically a line of text that may optionally be disp...
ZeroCrossing(float inputSampleRate)
void reset()
Reset the plugin after use, to prepare it for another clean run.
std::string getMaker() const
Get the name of the author or vendor of the plugin in human-readable form.
OutputList getOutputDescriptors() const
Get the outputs of this plugin.
FeatureSet process(const float *const *inputBuffers, Vamp::RealTime timestamp)
Process a single block of input data.
virtual ~ZeroCrossing()
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,...
std::string getIdentifier() const
Get the computer-usable name of the plugin.
std::string getCopyright() const
Get the copyright statement or licensing summary for the plugin.
std::vector< float > values
Results for a single sample of this feature.
bool hasTimestamp
True if an output feature has its own timestamp.
RealTime timestamp
Timestamp of the output feature.
SampleType sampleType
Positioning in time of the output results.
bool isQuantized
True if the output values are quantized to a particular resolution.
float quantizeStep
Quantization resolution of the output values (e.g.
std::string unit
The unit of the output, in human-readable form.
std::string name
The human-readable name of the output.
float sampleRate
Sample rate of the output results, as samples per second.
std::string identifier
The name of the output, in computer-usable form.
bool hasKnownExtents
True if the results in each output bin fall within a fixed numeric range (minimum and maximum values)...
bool hasFixedBinCount
True if the output has the same number of values per sample for every output sample.
std::string description
A human-readable short text describing the output.
size_t binCount
The number of values per result of the output.
RealTime represents time values to nanosecond precision with accurate arithmetic and frame-rate conve...
static RealTime frame2RealTime(long frame, unsigned int sampleRate)
Convert a sample frame at the given sample rate into a RealTime.