OpenShot Audio Library | OpenShotAudio  0.3.3
juce_ResamplingAudioSource.h
1 /*
2  ==============================================================================
3 
4  This file is part of the JUCE library.
5  Copyright (c) 2017 - ROLI Ltd.
6 
7  JUCE is an open source library subject to commercial or open-source
8  licensing.
9 
10  The code included in this file is provided under the terms of the ISC license
11  http://www.isc.org/downloads/software-support-policy/isc-license. Permission
12  To use, copy, modify, and/or distribute this software for any purpose with or
13  without fee is hereby granted provided that the above copyright notice and
14  this permission notice appear in all copies.
15 
16  JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
17  EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
18  DISCLAIMED.
19 
20  ==============================================================================
21 */
22 
23 namespace juce
24 {
25 
26 //==============================================================================
34 class JUCE_API ResamplingAudioSource : public AudioSource
35 {
36 public:
37  //==============================================================================
45  ResamplingAudioSource (AudioSource* inputSource,
46  bool deleteInputWhenDeleted,
47  int numChannels = 2);
48 
50  ~ResamplingAudioSource() override;
51 
60  void setResamplingRatio (double samplesInPerOutputSample);
61 
66  double getResamplingRatio() const noexcept { return ratio; }
67 
69  void flushBuffers();
70 
71  //==============================================================================
72  void prepareToPlay (int samplesPerBlockExpected, double sampleRate) override;
73  void releaseResources() override;
74  void getNextAudioBlock (const AudioSourceChannelInfo&) override;
75 
76 private:
77  //==============================================================================
79  double ratio = 1.0, lastRatio = 1.0;
80  AudioBuffer<float> buffer;
81  int bufferPos = 0, sampsInBuffer = 0;
82  double subSampleOffset = 0.0;
83  double coefficients[6];
84  SpinLock ratioLock;
85  CriticalSection callbackLock;
86  const int numChannels;
87  HeapBlock<float*> destBuffers;
88  HeapBlock<const float*> srcBuffers;
89 
90  void setFilterCoefficients (double c1, double c2, double c3, double c4, double c5, double c6);
91  void createLowPass (double proportionalRate);
92 
93  struct FilterState
94  {
95  double x1, x2, y1, y2;
96  };
97 
98  HeapBlock<FilterState> filterStates;
99  void resetFilters();
100 
101  void applyFilter (float* samples, int num, FilterState& fs);
102 
103  JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (ResamplingAudioSource)
104 };
105 
106 } // namespace juce
double getResamplingRatio() const noexcept