OpenShot Library | OpenShotAudio  0.2.2
juce_Gain.h
1 
2 /** @weakgroup juce_dsp-processors
3  * @{
4  */
5 /*
6  ==============================================================================
7 
8  This file is part of the JUCE library.
9  Copyright (c) 2017 - ROLI Ltd.
10 
11  JUCE is an open source library subject to commercial or open-source
12  licensing.
13 
14  By using JUCE, you agree to the terms of both the JUCE 5 End-User License
15  Agreement and JUCE 5 Privacy Policy (both updated and effective as of the
16  27th April 2017).
17 
18  End User License Agreement: www.juce.com/juce-5-licence
19  Privacy Policy: www.juce.com/juce-5-privacy-policy
20 
21  Or: You may also use this code under the terms of the GPL v3 (see
22  www.gnu.org/licenses).
23 
24  JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
25  EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
26  DISCLAIMED.
27 
28  ==============================================================================
29 */
30 
31 namespace juce
32 {
33 namespace dsp
34 {
35 
36 /**
37  Applies a gain to audio samples as single samples or AudioBlocks.
38 
39  @tags{DSP}
40 */
41 template <typename FloatType>
42 class Gain
43 {
44 public:
45  Gain() noexcept = default;
46 
47  //==============================================================================
48  /** Applies a new gain as a linear value. */
49  void setGainLinear (FloatType newGain) noexcept { gain.setTargetValue (newGain); }
50 
51  /** Applies a new gain as a decibel value. */
52  void setGainDecibels (FloatType newGainDecibels) noexcept { setGainLinear (Decibels::decibelsToGain<FloatType> (newGainDecibels)); }
53 
54  /** Returns the current gain as a linear value. */
55  FloatType getGainLinear() const noexcept { return gain.getTargetValue(); }
56 
57  /** Returns the current gain in decibels. */
58  FloatType getGainDecibels() const noexcept { return Decibels::gainToDecibels<FloatType> (getGainLinear()); }
59 
60  /** Sets the length of the ramp used for smoothing gain changes. */
61  void setRampDurationSeconds (double newDurationSeconds) noexcept
62  {
63  if (rampDurationSeconds != newDurationSeconds)
64  {
65  rampDurationSeconds = newDurationSeconds;
66  reset();
67  }
68  }
69 
70  /** Returns the ramp duration in seconds. */
71  double getRampDurationSeconds() const noexcept { return rampDurationSeconds; }
72 
73  /** Returns true if the current value is currently being interpolated. */
74  bool isSmoothing() const noexcept { return gain.isSmoothing(); }
75 
76  //==============================================================================
77  /** Called before processing starts. */
78  void prepare (const ProcessSpec& spec) noexcept
79  {
80  sampleRate = spec.sampleRate;
81  reset();
82  }
83 
84  /** Resets the internal state of the gain */
85  void reset() noexcept
86  {
87  if (sampleRate > 0)
88  gain.reset (sampleRate, rampDurationSeconds);
89  }
90 
91  //==============================================================================
92  /** Returns the result of processing a single sample. */
93  template <typename SampleType>
94  SampleType JUCE_VECTOR_CALLTYPE processSample (SampleType s) noexcept
95  {
96  return s * gain.getNextValue();
97  }
98 
99  /** Processes the input and output buffers supplied in the processing context. */
100  template <typename ProcessContext>
101  void process (const ProcessContext& context) noexcept
102  {
103  auto&& inBlock = context.getInputBlock();
104  auto&& outBlock = context.getOutputBlock();
105 
106  jassert (inBlock.getNumChannels() == outBlock.getNumChannels());
107  jassert (inBlock.getNumSamples() == outBlock.getNumSamples());
108 
109  auto len = inBlock.getNumSamples();
110  auto numChannels = inBlock.getNumChannels();
111 
112  if (context.isBypassed)
113  {
114  gain.skip (static_cast<int> (len));
115 
116  if (context.usesSeparateInputAndOutputBlocks())
117  outBlock.copyFrom (inBlock);
118 
119  return;
120  }
121 
122  if (numChannels == 1)
123  {
124  auto* src = inBlock.getChannelPointer (0);
125  auto* dst = outBlock.getChannelPointer (0);
126 
127  for (size_t i = 0; i < len; ++i)
128  dst[i] = src[i] * gain.getNextValue();
129  }
130  else
131  {
132  auto* gains = static_cast<FloatType*> (alloca (sizeof (FloatType) * len));
133 
134  for (size_t i = 0; i < len; ++i)
135  gains[i] = gain.getNextValue();
136 
137  for (size_t chan = 0; chan < numChannels; ++chan)
138  FloatVectorOperations::multiply (outBlock.getChannelPointer (chan),
139  inBlock.getChannelPointer (chan),
140  gains, static_cast<int> (len));
141  }
142  }
143 
144 private:
145  //==============================================================================
147  double sampleRate = 0, rampDurationSeconds = 0;
148 };
149 
150 } // namespace dsp
151 } // namespace juce
152 
153 /** @}*/
static void JUCE_CALLTYPE multiply(float *dest, const float *src, int numValues) noexcept
Multiplies the destination values by the source values.
A utility class for values that need smoothing to avoid audio glitches.
Applies a gain to audio samples as single samples or AudioBlocks.
Definition: juce_Gain.h:43
FloatType getGainDecibels() const noexcept
Returns the current gain in decibels.
Definition: juce_Gain.h:58
FloatType getGainLinear() const noexcept
Returns the current gain as a linear value.
Definition: juce_Gain.h:55
void prepare(const ProcessSpec &spec) noexcept
Called before processing starts.
Definition: juce_Gain.h:78
double getRampDurationSeconds() const noexcept
Returns the ramp duration in seconds.
Definition: juce_Gain.h:71
bool isSmoothing() const noexcept
Returns true if the current value is currently being interpolated.
Definition: juce_Gain.h:74
void setGainLinear(FloatType newGain) noexcept
Applies a new gain as a linear value.
Definition: juce_Gain.h:49
SampleType JUCE_VECTOR_CALLTYPE processSample(SampleType s) noexcept
Returns the result of processing a single sample.
Definition: juce_Gain.h:94
void reset() noexcept
Resets the internal state of the gain.
Definition: juce_Gain.h:85
void process(const ProcessContext &context) noexcept
Processes the input and output buffers supplied in the processing context.
Definition: juce_Gain.h:101
void setRampDurationSeconds(double newDurationSeconds) noexcept
Sets the length of the ramp used for smoothing gain changes.
Definition: juce_Gain.h:61
void setGainDecibels(FloatType newGainDecibels) noexcept
Applies a new gain as a decibel value.
Definition: juce_Gain.h:52
This structure is passed into a DSP algorithm's prepare() method, and contains information about vari...