Convolution Class Reference

Performs stereo uniform-partitioned convolution of an input signal with an impulse response in the frequency domain, using the juce FFT class. More...

#include <juce_Convolution.h>

Collaboration diagram for Convolution:

Public Member Functions
	Convolution ()
	Initialises an object for performing convolution in the frequency domain. More...
	~Convolution ()
	Destructor. More...
void	copyAndLoadImpulseResponseFromBuffer (const AudioBuffer< float > &buffer, double bufferSampleRate, bool wantsStereo, size_t size)
	This function loads an impulse response from an audio buffer, which is copied before doing anything else. More...
void	loadImpulseResponse (const void *sourceData, size_t sourceDataSize, bool wantsStereo, size_t size)
	This function loads an impulse response audio file from memory, added in a JUCE project with the Projucer as binary data. More...
void	loadImpulseResponse (const File &fileImpulseResponse, bool wantsStereo, size_t size)
	This function loads an impulse response from an audio file on any drive. More...
void	prepare (const ProcessSpec &)
	Must be called before loading any impulse response, to provide to the convolution the maximumBufferSize to handle, and the sample rate useful for optional resampling. More...
template<typename ProcessContext >
void	process (const ProcessContext &context) noexcept
	Performs the filter operation on the given set of samples, with optional stereo processing. More...
void	reset () noexcept
	Resets the processing pipeline, ready to start a new stream of data. More...

Private Member Functions
void	processSamples (const AudioBlock< float > &, AudioBlock< float > &, bool isBypassed) noexcept

Private Attributes
bool	currentIsBypassed = false
AudioBlock< float >	dryBuffer
HeapBlock< char >	dryBufferStorage
ScopedPointer< Pimpl >	pimpl
double	sampleRate
LinearSmoothedValue< float >	volumeDry [2]
LinearSmoothedValue< float >	volumeWet [2]

Detailed Description

Performs stereo uniform-partitioned convolution of an input signal with an impulse response in the frequency domain, using the juce FFT class.

It provides some thread-safe functions to load impulse responses as well, from audio files or memory on the fly without any noticeable artefacts, performing resampling and trimming if necessary.

The processing is equivalent to the time domain convolution done in the class FIRFilter, with a FIRFilter::Coefficients object having as coefficients the samples of the impulse response. However, it is more efficient in general to do frequency domain convolution when the size of the impulse response is higher than 64 samples.

See also

FIRFilter, FIRFilter::Coefficients, FFT

Constructor & Destructor Documentation

Convolution()

Convolution::Convolution

(

)

Initialises an object for performing convolution in the frequency domain.

~Convolution()

Convolution::~Convolution

(

)

Destructor.

Member Function Documentation

copyAndLoadImpulseResponseFromBuffer()

void Convolution::copyAndLoadImpulseResponseFromBuffer	(	const AudioBuffer< float > &	buffer,
		double	bufferSampleRate,
		bool	wantsStereo,
		size_t	size
	)

This function loads an impulse response from an audio buffer, which is copied before doing anything else.

Performs some resampling and pre-processing as well if needed.

Parameters

buffer	the AudioBuffer to use
bufferSampleRate	the sampleRate of the data in the AudioBuffer
wantsStereo	requests to load both stereo channels or only one mono channel
size	the expected size for the impulse response after loading

loadImpulseResponse() [1/2]

void Convolution::loadImpulseResponse	(	const void *	sourceData,
		size_t	sourceDataSize,
		bool	wantsStereo,
		size_t	size
	)

This function loads an impulse response audio file from memory, added in a JUCE project with the Projucer as binary data.

It can load any of the audio formats registered in JUCE, and performs some resampling and pre-processing as well if needed.

Note : obviously, don't try to use this function on float samples, since the data is supposed to be an audio file in its binary format, and be sure that the original data is not going to move at all its memory location during the process !!

Parameters

sourceData	the block of data to use as the stream's source
sourceDataSize	the number of bytes in the source data block
wantsStereo	requests to load both stereo channels or only one mono channel
size	the expected size for the impulse response after loading

loadImpulseResponse() [2/2]

void Convolution::loadImpulseResponse	(	const File &	fileImpulseResponse,
		bool	wantsStereo,
		size_t	size
	)

This function loads an impulse response from an audio file on any drive.

It can load any of the audio formats registered in JUCE, and performs some resampling and pre-processing as well if needed.

Parameters

fileImpulseResponse	the location of the audio file
wantsStereo	requests to load both stereo channels or only one mono channel
size	the expected size for the impulse response after loading

prepare()

void Convolution::prepare

(

const ProcessSpec &

)

Must be called before loading any impulse response, to provide to the convolution the maximumBufferSize to handle, and the sample rate useful for optional resampling.

process()

template<typename ProcessContext >

void Convolution::process ( const ProcessContext &  context )

inlinenoexcept

Performs the filter operation on the given set of samples, with optional stereo processing.

processSamples()

void Convolution::processSamples ( const AudioBlock< float > &  , AudioBlock< float > &  , bool  isBypassed  )

privatenoexcept

reset()

void Convolution::reset ( )

noexcept

Resets the processing pipeline, ready to start a new stream of data.

Member Data Documentation

currentIsBypassed

bool Convolution::currentIsBypassed = false

private

dryBuffer

AudioBlock<float> Convolution::dryBuffer

private

dryBufferStorage

HeapBlock<char> Convolution::dryBufferStorage

private

pimpl

ScopedPointer<Pimpl> Convolution::pimpl

private

sampleRate

double Convolution::sampleRate

private

volumeDry

LinearSmoothedValue<float> Convolution::volumeDry[2]

private

volumeWet

LinearSmoothedValue<float> Convolution::volumeWet[2]

private

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The documentation for this class was generated from the following file:

• juce_Convolution.h