VampPluginSDK 2.10
AmplitudeFollower.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 This file copyright 2006 Dan Stowell.
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 "AmplitudeFollower.h"
38
39#include <cmath>
40
41#include <string>
42#include <vector>
43#include <iostream>
44#include <algorithm>
45
46using std::string;
47using std::vector;
48using std::cerr;
49using std::endl;
50
57 Plugin(inputSampleRate),
58 m_stepSize(0),
59 m_previn(0.0f),
60 m_clampcoef(0.01f),
61 m_relaxcoef(0.01f)
62{
63}
64
66{
67}
68
69string
71{
72 return "amplitudefollower";
73}
74
75string
77{
78 return "Amplitude Follower";
79}
80
81string
83{
84 return "Track the amplitude of the audio signal";
85}
86
87string
89{
90 return "Vamp SDK Example Plugins";
91}
92
93int
95{
96 return 1;
97}
98
99string
101{
102 return "Code copyright 2006 Dan Stowell; method from SuperCollider. Freely redistributable (BSD license)";
103}
104
105bool
106AmplitudeFollower::initialise(size_t channels, size_t stepSize, size_t blockSize)
107{
108 if (channels < getMinChannelCount() ||
109 channels > getMaxChannelCount()) {
110 cerr << "ERROR: AmplitudeFollower::initialise: "
111 << "channel count " << channels << " out of supported range"
112 << endl;
113 return false;
114 }
115
116 m_stepSize = std::min(stepSize, blockSize);
117
118 // Translate the coefficients
119 // from their "convenient" 60dB convergence-time values
120 // to real coefficients
121 m_clampcoef = m_clampcoef==0.0 ? 0.0 : exp(log(0.1)/(m_clampcoef * m_inputSampleRate));
122 m_relaxcoef = m_relaxcoef==0.0 ? 0.0 : exp(log(0.1)/(m_relaxcoef * m_inputSampleRate));
123
124 return true;
125}
126
127void
129{
130 m_previn = 0.0f;
131}
132
135{
136 OutputList list;
137
139 sca.identifier = "amplitude";
140 sca.name = "Amplitude";
141 sca.description = "The peak tracked amplitude for the current processing block";
142 sca.unit = "V";
143 sca.hasFixedBinCount = true;
144 sca.binCount = 1;
145 sca.hasKnownExtents = false;
146 sca.isQuantized = false;
147 sca.sampleType = OutputDescriptor::OneSamplePerStep;
148 list.push_back(sca);
149
150 return list;
151}
152
155{
156 ParameterList list;
157
159 att.identifier = "attack";
160 att.name = "Attack time";
161 att.description = "The 60dB convergence time for an increase in amplitude";
162 att.unit = "s";
163 att.minValue = 0.0f;
164 att.maxValue = 1.f;
165 att.defaultValue = 0.01f;
166 att.isQuantized = false;
167
168 list.push_back(att);
169
171 dec.identifier = "release";
172 dec.name = "Release time";
173 dec.description = "The 60dB convergence time for a decrease in amplitude";
174 dec.unit = "s";
175 dec.minValue = 0.0f;
176 dec.maxValue = 1.f;
177 dec.defaultValue = 0.01f;
178 dec.isQuantized = false;
179
180 list.push_back(dec);
181
182 return list;
183}
184
185void AmplitudeFollower::setParameter(std::string paramid, float newval)
186{
187 if (paramid == "attack") {
188 m_clampcoef = newval;
189 } else if (paramid == "release") {
190 m_relaxcoef = newval;
191 }
192}
193
194float AmplitudeFollower::getParameter(std::string paramid) const
195{
196 if (paramid == "attack") {
197 return m_clampcoef;
198 } else if (paramid == "release") {
199 return m_relaxcoef;
200 }
201
202 return 0.0f;
203}
204
206AmplitudeFollower::process(const float *const *inputBuffers,
207 Vamp::RealTime /* timestamp */)
208{
209 if (m_stepSize == 0) {
210 cerr << "ERROR: AmplitudeFollower::process: "
211 << "AmplitudeFollower has not been initialised"
212 << endl;
213 return FeatureSet();
214 }
215
216 float previn = m_previn;
217
218 FeatureSet returnFeatures;
219
220 float val;
221 float peak = 0.0f;
222
223 for (size_t i = 0; i < m_stepSize; ++i) {
224
225 val = fabs(inputBuffers[0][i]);
226
227 if (val < previn) {
228 val = val + (previn - val) * m_relaxcoef;
229 } else {
230 val = val + (previn - val) * m_clampcoef;
231 }
232
233 if (val > peak) peak = val;
234 previn = val;
235 }
236
237 m_previn = previn;
238
239 // Now store the "feature" (peak amp) for this sample
240 Feature feature;
241 feature.hasTimestamp = false;
242 feature.values.push_back(peak);
243 returnFeatures[0].push_back(feature);
244
245 return returnFeatures;
246}
247
250{
251 return FeatureSet();
252}
253
AmplitudeFollower(float inputSampleRate)
An implementation of SuperCollider's amplitude-follower algorithm as a simple Vamp plugin.
FeatureSet getRemainingFeatures()
After all blocks have been processed, calculate and return any remaining features derived from the co...
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.
std::string getName() const
Get a human-readable name or title of the plugin.
ParameterList getParameterDescriptors() const
Get the controllable parameters of this plugin.
float getParameter(std::string paramid) const
Get the value of a named parameter.
std::string getDescription() const
Get a human-readable description for the plugin, typically a line of text that may optionally be disp...
std::string getMaker() const
Get the name of the author or vendor of the plugin in human-readable form.
std::string getCopyright() const
Get the copyright statement or licensing summary for the plugin.
void reset()
Reset the plugin after use, to prepare it for another clean run.
std::string getIdentifier() const
Get the computer-usable name of the plugin.
int getPluginVersion() const
Get the version number of the plugin.
void setParameter(std::string paramid, float newval)
Set a named parameter.
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::vector< ParameterDescriptor > ParameterList
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.
std::string name
The human-readable name of the parameter.
std::string identifier
The name of the parameter, in computer-usable form.
std::string unit
The unit of the parameter, in human-readable form.
std::string description
A human-readable short text describing the parameter.
bool isQuantized
True if the parameter values are quantized to a particular resolution.
float minValue
The minimum value of the parameter.
float maxValue
The maximum value of the parameter.
float defaultValue
The default value of the parameter.
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...