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juce::ResamplingAudioSource Class Reference

#include <juce_ResamplingAudioSource.h>

Inheritance diagram for juce::ResamplingAudioSource:
juce::AudioSource

Classes

struct  FilterState

Public Member Functions

 ResamplingAudioSource (AudioSource *inputSource, bool deleteInputWhenDeleted, int numChannels=2)
 ~ResamplingAudioSource () override
void setResamplingRatio (double samplesInPerOutputSample)
double getResamplingRatio () const noexcept
void flushBuffers ()
void prepareToPlay (int samplesPerBlockExpected, double sampleRate) override
void releaseResources () override
void getNextAudioBlock (const AudioSourceChannelInfo &) override
Public Member Functions inherited from juce::AudioSource
virtual ~AudioSource ()=default

Private Member Functions

void setFilterCoefficients (double c1, double c2, double c3, double c4, double c5, double c6)
void createLowPass (double proportionalRate)
void resetFilters ()
void applyFilter (float *samples, int num, FilterState &fs)

Private Attributes

OptionalScopedPointer< AudioSourceinput
double ratio = 1.0
double lastRatio = 1.0
AudioBuffer< float > buffer
int bufferPos = 0
int sampsInBuffer = 0
double subSampleOffset = 0.0
double coefficients [6]
SpinLock ratioLock
CriticalSection callbackLock
const int numChannels
HeapBlock< float * > destBuffers
HeapBlock< const float * > srcBuffers
HeapBlock< FilterStatefilterStates

Additional Inherited Members

Protected Member Functions inherited from juce::AudioSource
 AudioSource ()=default

Detailed Description

A type of AudioSource that takes an input source and changes its sample rate.

See also
AudioSource, LagrangeInterpolator, CatmullRomInterpolator

@tags{Audio}

Constructor & Destructor Documentation

◆ ResamplingAudioSource()

juce::ResamplingAudioSource::ResamplingAudioSource ( AudioSource * inputSource,
bool deleteInputWhenDeleted,
int numChannels = 2 )

Creates a ResamplingAudioSource for a given input source.

Parameters
inputSourcethe input source to read from
deleteInputWhenDeletedif true, the input source will be deleted when this object is deleted
numChannelsthe number of channels to process

◆ ~ResamplingAudioSource()

juce::ResamplingAudioSource::~ResamplingAudioSource ( )
override

Destructor.

Member Function Documentation

◆ applyFilter()

void juce::ResamplingAudioSource::applyFilter ( float * samples,
int num,
FilterState & fs )
private

◆ createLowPass()

void juce::ResamplingAudioSource::createLowPass ( double proportionalRate)
private

◆ flushBuffers()

void juce::ResamplingAudioSource::flushBuffers ( )

Clears any buffers and filters that the resampler is using.

◆ getNextAudioBlock()

void juce::ResamplingAudioSource::getNextAudioBlock ( const AudioSourceChannelInfo & bufferToFill)
overridevirtual

Called repeatedly to fetch subsequent blocks of audio data.

After calling the prepareToPlay() method, this callback will be made each time the audio playback hardware (or whatever other destination the audio data is going to) needs another block of data.

It will generally be called on a high-priority system thread, or possibly even an interrupt, so be careful not to do too much work here, as that will cause audio glitches!

See also
AudioSourceChannelInfo, prepareToPlay, releaseResources

Implements juce::AudioSource.

◆ getResamplingRatio()

double juce::ResamplingAudioSource::getResamplingRatio ( ) const
inlinenoexcept

Returns the current resampling ratio.

This is the value that was set by setResamplingRatio().

◆ prepareToPlay()

void juce::ResamplingAudioSource::prepareToPlay ( int samplesPerBlockExpected,
double sampleRate )
overridevirtual

Tells the source to prepare for playing.

An AudioSource has two states: prepared and unprepared.

The prepareToPlay() method is guaranteed to be called at least once on an 'unprepared' source to put it into a 'prepared' state before any calls will be made to getNextAudioBlock(). This callback allows the source to initialise any resources it might need when playing.

Once playback has finished, the releaseResources() method is called to put the stream back into an 'unprepared' state.

Note that this method could be called more than once in succession without a matching call to releaseResources(), so make sure your code is robust and can handle that kind of situation.

Parameters
samplesPerBlockExpectedthe number of samples that the source will be expected to supply each time its getNextAudioBlock() method is called. This number may vary slightly, because it will be dependent on audio hardware callbacks, and these aren't guaranteed to always use a constant block size, so the source should be able to cope with small variations.
sampleRatethe sample rate that the output will be used at - this is needed by sources such as tone generators.
See also
releaseResources, getNextAudioBlock

Implements juce::AudioSource.

◆ releaseResources()

void juce::ResamplingAudioSource::releaseResources ( )
overridevirtual

Allows the source to release anything it no longer needs after playback has stopped.

This will be called when the source is no longer going to have its getNextAudioBlock() method called, so it should release any spare memory, etc. that it might have allocated during the prepareToPlay() call.

Note that there's no guarantee that prepareToPlay() will actually have been called before releaseResources(), and it may be called more than once in succession, so make sure your code is robust and doesn't make any assumptions about when it will be called.

See also
prepareToPlay, getNextAudioBlock

Implements juce::AudioSource.

◆ resetFilters()

void juce::ResamplingAudioSource::resetFilters ( )
private

◆ setFilterCoefficients()

void juce::ResamplingAudioSource::setFilterCoefficients ( double c1,
double c2,
double c3,
double c4,
double c5,
double c6 )
private

◆ setResamplingRatio()

void juce::ResamplingAudioSource::setResamplingRatio ( double samplesInPerOutputSample)

Changes the resampling ratio.

(This value can be changed at any time, even while the source is running).

Parameters
samplesInPerOutputSampleif 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

Member Data Documentation

◆ buffer

AudioBuffer<float> juce::ResamplingAudioSource::buffer
private

◆ bufferPos

int juce::ResamplingAudioSource::bufferPos = 0
private

◆ callbackLock

CriticalSection juce::ResamplingAudioSource::callbackLock
private

◆ coefficients

double juce::ResamplingAudioSource::coefficients[6]
private

◆ destBuffers

HeapBlock<float*> juce::ResamplingAudioSource::destBuffers
private

◆ filterStates

HeapBlock<FilterState> juce::ResamplingAudioSource::filterStates
private

◆ input

OptionalScopedPointer<AudioSource> juce::ResamplingAudioSource::input
private

◆ lastRatio

double juce::ResamplingAudioSource::lastRatio = 1.0
private

◆ numChannels

const int juce::ResamplingAudioSource::numChannels
private

◆ ratio

double juce::ResamplingAudioSource::ratio = 1.0
private

◆ ratioLock

SpinLock juce::ResamplingAudioSource::ratioLock
private

◆ sampsInBuffer

int juce::ResamplingAudioSource::sampsInBuffer = 0
private

◆ srcBuffers

HeapBlock<const float*> juce::ResamplingAudioSource::srcBuffers
private

◆ subSampleOffset

double juce::ResamplingAudioSource::subSampleOffset = 0.0
private

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