VampPluginSDK  2.4
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 
45 using std::string;
46 using std::vector;
47 using std::cerr;
48 using std::endl;
49 
55 AmplitudeFollower::AmplitudeFollower(float inputSampleRate) :
56  Plugin(inputSampleRate),
57  m_stepSize(0),
58  m_previn(0.0f),
59  m_clampcoef(0.01f),
60  m_relaxcoef(0.01f)
61 {
62 }
63 
65 {
66 }
67 
68 string
70 {
71  return "amplitudefollower";
72 }
73 
74 string
76 {
77  return "Amplitude Follower";
78 }
79 
80 string
82 {
83  return "Track the amplitude of the audio signal";
84 }
85 
86 string
88 {
89  return "Vamp SDK Example Plugins";
90 }
91 
92 int
94 {
95  return 1;
96 }
97 
98 string
100 {
101  return "Code copyright 2006 Dan Stowell; method from SuperCollider. Freely redistributable (BSD license)";
102 }
103 
104 bool
105 AmplitudeFollower::initialise(size_t channels, size_t stepSize, size_t blockSize)
106 {
107  if (channels < getMinChannelCount() ||
108  channels > getMaxChannelCount()) return false;
109 
110  m_stepSize = std::min(stepSize, blockSize);
111 
112  // Translate the coefficients
113  // from their "convenient" 60dB convergence-time values
114  // to real coefficients
115  m_clampcoef = m_clampcoef==0.0 ? 0.0 : exp(log(0.1)/(m_clampcoef * m_inputSampleRate));
116  m_relaxcoef = m_relaxcoef==0.0 ? 0.0 : exp(log(0.1)/(m_relaxcoef * m_inputSampleRate));
117 
118  return true;
119 }
120 
121 void
123 {
124  m_previn = 0.0f;
125 }
126 
129 {
130  OutputList list;
131 
132  OutputDescriptor sca;
133  sca.identifier = "amplitude";
134  sca.name = "Amplitude";
135  sca.description = "The peak tracked amplitude for the current processing block";
136  sca.unit = "V";
137  sca.hasFixedBinCount = true;
138  sca.binCount = 1;
139  sca.hasKnownExtents = false;
140  sca.isQuantized = false;
142  list.push_back(sca);
143 
144  return list;
145 }
146 
149 {
150  ParameterList list;
151 
153  att.identifier = "attack";
154  att.name = "Attack time";
155  att.description = "The 60dB convergence time for an increase in amplitude";
156  att.unit = "s";
157  att.minValue = 0.0f;
158  att.maxValue = 1.f;
159  att.defaultValue = 0.01f;
160  att.isQuantized = false;
161 
162  list.push_back(att);
163 
165  dec.identifier = "release";
166  dec.name = "Release time";
167  dec.description = "The 60dB convergence time for a decrease in amplitude";
168  dec.unit = "s";
169  dec.minValue = 0.0f;
170  dec.maxValue = 1.f;
171  dec.defaultValue = 0.01f;
172  dec.isQuantized = false;
173 
174  list.push_back(dec);
175 
176  return list;
177 }
178 
179 void AmplitudeFollower::setParameter(std::string paramid, float newval)
180 {
181  if (paramid == "attack") {
182  m_clampcoef = newval;
183  } else if (paramid == "release") {
184  m_relaxcoef = newval;
185  }
186 }
187 
188 float AmplitudeFollower::getParameter(std::string paramid) const
189 {
190  if (paramid == "attack") {
191  return m_clampcoef;
192  } else if (paramid == "release") {
193  return m_relaxcoef;
194  }
195 
196  return 0.0f;
197 }
198 
200 AmplitudeFollower::process(const float *const *inputBuffers,
201  Vamp::RealTime timestamp)
202 {
203  if (m_stepSize == 0) {
204  cerr << "ERROR: AmplitudeFollower::process: "
205  << "AmplitudeFollower has not been initialised"
206  << endl;
207  return FeatureSet();
208  }
209 
210  float previn = m_previn;
211 
212  FeatureSet returnFeatures;
213 
214  float val;
215  float peak = 0.0f;
216 
217  for (size_t i = 0; i < m_stepSize; ++i) {
218 
219  val = fabs(inputBuffers[0][i]);
220 
221  if (val < previn) {
222  val = val + (previn - val) * m_relaxcoef;
223  } else {
224  val = val + (previn - val) * m_clampcoef;
225  }
226 
227  if (val > peak) peak = val;
228  previn = val;
229  }
230 
231  m_previn = previn;
232 
233  // Now store the "feature" (peak amp) for this sample
234  Feature feature;
235  feature.hasTimestamp = false;
236  feature.values.push_back(peak);
237  returnFeatures[0].push_back(feature);
238 
239  return returnFeatures;
240 }
241 
244 {
245  return FeatureSet();
246 }
247