106 lines
3.8 KiB
C++
106 lines
3.8 KiB
C++
/*
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==============================================================================
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This file is part of the JUCE library.
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Copyright (c) 2017 - ROLI Ltd.
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JUCE is an open source library subject to commercial or open-source
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licensing.
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The code included in this file is provided under the terms of the ISC license
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http://www.isc.org/downloads/software-support-policy/isc-license. Permission
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To use, copy, modify, and/or distribute this software for any purpose with or
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without fee is hereby granted provided that the above copyright notice and
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this permission notice appear in all copies.
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JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
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EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
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DISCLAIMED.
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==============================================================================
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*/
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namespace juce
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{
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//==============================================================================
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/**
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A type of AudioSource that takes an input source and changes its sample rate.
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@see AudioSource, LagrangeInterpolator, CatmullRomInterpolator
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@tags{Audio}
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*/
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class JUCE_API ResamplingAudioSource : public AudioSource
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{
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public:
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//==============================================================================
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/** Creates a ResamplingAudioSource for a given input source.
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@param inputSource the input source to read from
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@param deleteInputWhenDeleted if true, the input source will be deleted when
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this object is deleted
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@param numChannels the number of channels to process
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*/
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ResamplingAudioSource (AudioSource* inputSource,
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bool deleteInputWhenDeleted,
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int numChannels = 2);
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/** Destructor. */
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~ResamplingAudioSource();
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/** Changes the resampling ratio.
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(This value can be changed at any time, even while the source is running).
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@param samplesInPerOutputSample if set to 1.0, the input is passed through; higher
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values will speed it up; lower values will slow it
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down. The ratio must be greater than 0
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*/
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void setResamplingRatio (double samplesInPerOutputSample);
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/** Returns the current resampling ratio.
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This is the value that was set by setResamplingRatio().
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*/
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double getResamplingRatio() const noexcept { return ratio; }
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/** Clears any buffers and filters that the resampler is using. */
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void flushBuffers();
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//==============================================================================
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void prepareToPlay (int samplesPerBlockExpected, double sampleRate) override;
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void releaseResources() override;
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void getNextAudioBlock (const AudioSourceChannelInfo&) override;
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private:
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//==============================================================================
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OptionalScopedPointer<AudioSource> input;
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double ratio, lastRatio;
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AudioBuffer<float> buffer;
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int bufferPos, sampsInBuffer;
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double subSampleOffset;
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double coefficients[6];
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SpinLock ratioLock;
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const int numChannels;
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HeapBlock<float*> destBuffers;
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HeapBlock<const float*> srcBuffers;
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void setFilterCoefficients (double c1, double c2, double c3, double c4, double c5, double c6);
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void createLowPass (double proportionalRate);
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struct FilterState
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{
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double x1, x2, y1, y2;
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};
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HeapBlock<FilterState> filterStates;
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void resetFilters();
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void applyFilter (float* samples, int num, FilterState& fs);
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JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (ResamplingAudioSource)
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};
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} // namespace juce
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