VampPluginSDK 2.10
PowerSpectrum.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 2008 QMUL.
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 "PowerSpectrum.h"
38
39using std::string;
40using std::cerr;
41using std::endl;
42
43#include <math.h>
44
45PowerSpectrum::PowerSpectrum(float inputSampleRate) :
46 Plugin(inputSampleRate),
47 m_blockSize(0)
48{
49}
50
52{
53}
54
55string
57{
58 return "powerspectrum";
59}
60
61string
63{
64 return "Simple Power Spectrum";
65}
66
67string
69{
70 return "Return the power spectrum of a signal";
71}
72
73string
75{
76 return "Vamp SDK Example Plugins";
77}
78
79int
81{
82 return 1;
83}
84
85string
87{
88 return "Freely redistributable (BSD license)";
89}
90
91bool
92PowerSpectrum::initialise(size_t channels, size_t, size_t blockSize)
93{
94 if (channels < getMinChannelCount() ||
95 channels > getMaxChannelCount()) return false;
96
97 m_blockSize = blockSize;
98
99 return true;
100}
101
102void
104{
105}
106
109{
110 OutputList list;
111
113 d.identifier = "powerspectrum";
114 d.name = "Power Spectrum";
115 d.description = "Power values of the frequency spectrum bins calculated from the input signal";
116 d.unit = "";
117 d.hasFixedBinCount = true;
118 if (m_blockSize == 0) {
119 // Just so as not to return "1". This is the bin count that
120 // would result from a block size of 1024, which is a likely
121 // default -- but the host should always set the block size
122 // before querying the bin count for certain.
123 d.binCount = 513;
124 } else {
125 d.binCount = m_blockSize / 2 + 1;
126 }
127 d.hasKnownExtents = false;
128 d.isQuantized = false;
129 d.sampleType = OutputDescriptor::OneSamplePerStep;
130 list.push_back(d);
131
132 return list;
133}
134
136PowerSpectrum::process(const float *const *inputBuffers, Vamp::RealTime)
137{
138 FeatureSet fs;
139
140 if (m_blockSize == 0) {
141 cerr << "ERROR: PowerSpectrum::process: Not initialised" << endl;
142 return fs;
143 }
144
145 size_t n = m_blockSize / 2 + 1;
146 const float *fbuf = inputBuffers[0];
147
148 Feature feature;
149 feature.hasTimestamp = false;
150 feature.values.reserve(n); // optional
151
152 for (size_t i = 0; i < n; ++i) {
153
154 double real = fbuf[i * 2];
155 double imag = fbuf[i * 2 + 1];
156
157 feature.values.push_back(real * real + imag * imag);
158 }
159
160 fs[0].push_back(feature);
161
162 return fs;
163}
164
167{
168 return FeatureSet();
169}
170
std::string getDescription() const
Get a human-readable description for the plugin, typically a line of text that may optionally be disp...
void reset()
Reset the plugin after use, to prepare it for another clean run.
size_t m_blockSize
Definition: PowerSpectrum.h:76
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.
std::string getIdentifier() const
Get the computer-usable name of the plugin.
std::string getName() const
Get a human-readable name or title of the plugin.
PowerSpectrum(float inputSampleRate)
FeatureSet process(const float *const *inputBuffers, Vamp::RealTime timestamp)
Process a single block of input data.
std::string getCopyright() const
Get the copyright statement or licensing summary for the plugin.
FeatureSet getRemainingFeatures()
After all blocks have been processed, calculate and return any remaining features derived from the co...
int getPluginVersion() const
Get the version number of the plugin.
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,...
virtual ~PowerSpectrum()
virtual size_t getMaxChannelCount() const
Get the maximum supported number of input channels.
std::vector< OutputDescriptor > OutputList
std::map< int, FeatureList > FeatureSet
virtual size_t getMinChannelCount() const
Get the minimum supported number of input channels.
std::vector< float > values
Results for a single sample of this feature.
bool hasTimestamp
True if an output feature has its own timestamp.
SampleType sampleType
Positioning in time of the output results.
bool isQuantized
True if the output values are quantized to a particular resolution.
std::string unit
The unit of the output, in human-readable form.
std::string name
The human-readable name of the output.
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...