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 
46 using std::string;
47 using std::vector;
48 using std::cerr;
49 using std::endl;
50 
56 AmplitudeFollower::AmplitudeFollower(float inputSampleRate) :
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 
69 string
71 {
72  return "amplitudefollower";
73 }
74 
75 string
77 {
78  return "Amplitude Follower";
79 }
80 
81 string
83 {
84  return "Track the amplitude of the audio signal";
85 }
86 
87 string
89 {
90  return "Vamp SDK Example Plugins";
91 }
92 
93 int
95 {
96  return 1;
97 }
98 
99 string
101 {
102  return "Code copyright 2006 Dan Stowell; method from SuperCollider. Freely redistributable (BSD license)";
103 }
104 
105 bool
106 AmplitudeFollower::initialise(size_t channels, size_t stepSize, size_t blockSize)
107 {
108  if (channels < getMinChannelCount() ||
109  channels > getMaxChannelCount()) return false;
110 
111  m_stepSize = std::min(stepSize, blockSize);
112 
113  // Translate the coefficients
114  // from their "convenient" 60dB convergence-time values
115  // to real coefficients
116  m_clampcoef = m_clampcoef==0.0 ? 0.0 : exp(log(0.1)/(m_clampcoef * m_inputSampleRate));
117  m_relaxcoef = m_relaxcoef==0.0 ? 0.0 : exp(log(0.1)/(m_relaxcoef * m_inputSampleRate));
118 
119  return true;
120 }
121 
122 void
124 {
125  m_previn = 0.0f;
126 }
127 
130 {
131  OutputList list;
132 
133  OutputDescriptor sca;
134  sca.identifier = "amplitude";
135  sca.name = "Amplitude";
136  sca.description = "The peak tracked amplitude for the current processing block";
137  sca.unit = "V";
138  sca.hasFixedBinCount = true;
139  sca.binCount = 1;
140  sca.hasKnownExtents = false;
141  sca.isQuantized = false;
143  list.push_back(sca);
144 
145  return list;
146 }
147 
150 {
151  ParameterList list;
152 
154  att.identifier = "attack";
155  att.name = "Attack time";
156  att.description = "The 60dB convergence time for an increase in amplitude";
157  att.unit = "s";
158  att.minValue = 0.0f;
159  att.maxValue = 1.f;
160  att.defaultValue = 0.01f;
161  att.isQuantized = false;
162 
163  list.push_back(att);
164 
166  dec.identifier = "release";
167  dec.name = "Release time";
168  dec.description = "The 60dB convergence time for a decrease in amplitude";
169  dec.unit = "s";
170  dec.minValue = 0.0f;
171  dec.maxValue = 1.f;
172  dec.defaultValue = 0.01f;
173  dec.isQuantized = false;
174 
175  list.push_back(dec);
176 
177  return list;
178 }
179 
180 void AmplitudeFollower::setParameter(std::string paramid, float newval)
181 {
182  if (paramid == "attack") {
183  m_clampcoef = newval;
184  } else if (paramid == "release") {
185  m_relaxcoef = newval;
186  }
187 }
188 
189 float AmplitudeFollower::getParameter(std::string paramid) const
190 {
191  if (paramid == "attack") {
192  return m_clampcoef;
193  } else if (paramid == "release") {
194  return m_relaxcoef;
195  }
196 
197  return 0.0f;
198 }
199 
201 AmplitudeFollower::process(const float *const *inputBuffers,
202  Vamp::RealTime /* timestamp */)
203 {
204  if (m_stepSize == 0) {
205  cerr << "ERROR: AmplitudeFollower::process: "
206  << "AmplitudeFollower has not been initialised"
207  << endl;
208  return FeatureSet();
209  }
210 
211  float previn = m_previn;
212 
213  FeatureSet returnFeatures;
214 
215  float val;
216  float peak = 0.0f;
217 
218  for (size_t i = 0; i < m_stepSize; ++i) {
219 
220  val = fabs(inputBuffers[0][i]);
221 
222  if (val < previn) {
223  val = val + (previn - val) * m_relaxcoef;
224  } else {
225  val = val + (previn - val) * m_clampcoef;
226  }
227 
228  if (val > peak) peak = val;
229  previn = val;
230  }
231 
232  m_previn = previn;
233 
234  // Now store the "feature" (peak amp) for this sample
235  Feature feature;
236  feature.hasTimestamp = false;
237  feature.values.push_back(peak);
238  returnFeatures[0].push_back(feature);
239 
240  return returnFeatures;
241 }
242 
245 {
246  return FeatureSet();
247 }
248 
std::vector< OutputDescriptor > OutputList
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).
OutputList getOutputDescriptors() const
Get the outputs of this plugin.
AmplitudeFollower(float inputSampleRate)
An implementation of SuperCollider&#39;s amplitude-follower algorithm as a simple Vamp plugin...
bool hasFixedBinCount
True if the output has the same number of values per sample for every output sample.
std::vector< float > values
Results for a single sample of this feature.
std::map< int, FeatureList > FeatureSet
std::string identifier
The name of the parameter, in computer-usable form.
std::string description
A human-readable short text describing the output.
std::string identifier
The name of the output, in computer-usable form.
FeatureSet getRemainingFeatures()
After all blocks have been processed, calculate and return any remaining features derived from the co...
std::string name
The human-readable name of the parameter.
float m_inputSampleRate
std::string getMaker() const
Get the name of the author or vendor of the plugin in human-readable form.
float minValue
The minimum value of the parameter.
std::string unit
The unit of the parameter, in human-readable form.
std::string unit
The unit of the output, in human-readable form.
std::string name
The human-readable name of the output.
RealTime represents time values to nanosecond precision with accurate arithmetic and frame-rate conve...
bool hasTimestamp
True if an output feature has its own timestamp.
std::string description
A human-readable short text describing the parameter.
float maxValue
The maximum value of the parameter.
std::string getIdentifier() const
Get the computer-usable name of the plugin.
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.
std::string getName() const
Get a human-readable name or title of the plugin.
std::string getCopyright() const
Get the copyright statement or licensing summary for the plugin.
ParameterList getParameterDescriptors() const
Get the controllable parameters of this plugin.
Results from each process() align with that call&#39;s block start.
virtual size_t getMaxChannelCount() const
Get the maximum supported number of input channels.
size_t binCount
The number of values per result of the output.
int getPluginVersion() const
Get the version number of the plugin.
bool isQuantized
True if the output values are quantized to a particular resolution.
float defaultValue
The default value of the parameter.
void setParameter(std::string paramid, float newval)
Set a named parameter.
virtual size_t getMinChannelCount() const
Get the minimum supported number of input channels.
FeatureSet process(const float *const *inputBuffers, Vamp::RealTime timestamp)
Process a single block of input data.
bool isQuantized
True if the parameter values are quantized to a particular resolution.
SampleType sampleType
Positioning in time of the output results.
float getParameter(std::string paramid) const
Get the value of a named parameter.
bool hasKnownExtents
True if the results in each output bin fall within a fixed numeric range (minimum and maximum values)...
std::vector< ParameterDescriptor > ParameterList