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JUCE/modules/juce_audio_basics/sources/juce_ResamplingAudioSource.h

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C++

/*
==============================================================================
This file is part of the JUCE library - "Jules' Utility Class Extensions"
Copyright 2004-11 by Raw Material Software Ltd.
------------------------------------------------------------------------------
JUCE can be redistributed and/or modified under the terms of the GNU General
Public License (Version 2), as published by the Free Software Foundation.
A copy of the license is included in the JUCE distribution, or can be found
online at www.gnu.org/licenses.
JUCE is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
A PARTICULAR PURPOSE. See the GNU General Public License for more details.
------------------------------------------------------------------------------
To release a closed-source product which uses JUCE, commercial licenses are
available: visit www.rawmaterialsoftware.com/juce for more information.
==============================================================================
*/
#ifndef __JUCE_RESAMPLINGAUDIOSOURCE_JUCEHEADER__
#define __JUCE_RESAMPLINGAUDIOSOURCE_JUCEHEADER__
#include "juce_AudioSource.h"
//==============================================================================
/**
A type of AudioSource that takes an input source and changes its sample rate.
@see AudioSource
*/
class JUCE_API ResamplingAudioSource : public AudioSource
{
public:
//==============================================================================
/** Creates a ResamplingAudioSource for a given input source.
@param inputSource the input source to read from
@param deleteInputWhenDeleted if true, the input source will be deleted when
this object is deleted
@param numChannels the number of channels to process
*/
ResamplingAudioSource (AudioSource* inputSource,
bool deleteInputWhenDeleted,
int numChannels = 2);
/** Destructor. */
~ResamplingAudioSource();
/** Changes the resampling ratio.
(This value can be changed at any time, even while the source is running).
@param samplesInPerOutputSample if set to 1.0, the input is passed through; higher
values will speed it up; lower values will slow it
down. The ratio must be greater than 0
*/
void setResamplingRatio (double samplesInPerOutputSample);
/** Returns the current resampling ratio.
This is the value that was set by setResamplingRatio().
*/
double getResamplingRatio() const noexcept { return ratio; }
//==============================================================================
void prepareToPlay (int samplesPerBlockExpected, double sampleRate);
void releaseResources();
void getNextAudioBlock (const AudioSourceChannelInfo& bufferToFill);
private:
//==============================================================================
OptionalScopedPointer<AudioSource> input;
double ratio, lastRatio;
AudioSampleBuffer buffer;
int bufferPos, sampsInBuffer;
double subSampleOffset;
double coefficients[6];
SpinLock ratioLock;
const int numChannels;
HeapBlock<float*> destBuffers, srcBuffers;
void setFilterCoefficients (double c1, double c2, double c3, double c4, double c5, double c6);
void createLowPass (double proportionalRate);
struct FilterState
{
double x1, x2, y1, y2;
};
HeapBlock<FilterState> filterStates;
void resetFilters();
void applyFilter (float* samples, int num, FilterState& fs);
JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (ResamplingAudioSource);
};
#endif // __JUCE_RESAMPLINGAUDIOSOURCE_JUCEHEADER__