ARAPlaybackRegionReader Class Reference

Subclass of AudioFormatReader that reads samples from a group of playback regions. More...

Inheritance diagram for ARAPlaybackRegionReader:

Public Member Functions
	ARAPlaybackRegionReader (ARAPlaybackRegion *playbackRegion)
	Create an ARAPlaybackRegionReader instance to read the given playbackRegion, using the sample rate and channel count of the underlying ARAAudioSource.
	ARAPlaybackRegionReader (double sampleRate, int numChannels, const std::vector< ARAPlaybackRegion * > &playbackRegions)
	Create an ARAPlaybackRegionReader instance to read the given playbackRegions.
	~ARAPlaybackRegionReader () override
bool	isValid () const
	Returns true as long as any of the reader's underlying playback region's haven't changed.
void	invalidate ()
	Invalidate the reader - this should be called if the sample content of any of the reader's ARAPlaybackRegions changes.
bool	readSamples (int *const *destSamples, int numDestChannels, int startOffsetInDestBuffer, int64 startSampleInFile, int numSamples) override
	Subclasses must implement this method to perform the low-level read operation.
void	willUpdatePlaybackRegionProperties (ARAPlaybackRegion *playbackRegion, ARAPlaybackRegion::PropertiesPtr newProperties) override
	Called before the playback region's properties are updated.
void	didUpdatePlaybackRegionContent (ARAPlaybackRegion *playbackRegion, ARAContentUpdateScopes scopeFlags) override
	Called when the playback region's content (i.e.
void	willDestroyPlaybackRegion (ARAPlaybackRegion *playbackRegion) override
	Called before the playback region is destroyed.
Public Member Functions inherited from AudioFormatReader
virtual	~AudioFormatReader ()
	Destructor.
const String &	getFormatName () const noexcept
	Returns a description of what type of format this is.
bool	read (float *const *destChannels, int numDestChannels, int64 startSampleInSource, int numSamplesToRead)
	Reads samples from the stream.
bool	read (int *const *destChannels, int numDestChannels, int64 startSampleInSource, int numSamplesToRead, bool fillLeftoverChannelsWithCopies)
	Reads samples from the stream.
bool	read (AudioBuffer< float > *buffer, int startSampleInDestBuffer, int numSamples, int64 readerStartSample, bool useReaderLeftChan, bool useReaderRightChan)
	Fills a section of an AudioBuffer from this reader.
virtual void	readMaxLevels (int64 startSample, int64 numSamples, Range< float > *results, int numChannelsToRead)
	Finds the highest and lowest sample levels from a section of the audio stream.
virtual void	readMaxLevels (int64 startSample, int64 numSamples, float &lowestLeft, float &highestLeft, float &lowestRight, float &highestRight)
	Finds the highest and lowest sample levels from a section of the audio stream.
int64	searchForLevel (int64 startSample, int64 numSamplesToSearch, double magnitudeRangeMinimum, double magnitudeRangeMaximum, int minimumConsecutiveSamples)
	Scans the source looking for a sample whose magnitude is in a specified range.
virtual AudioChannelSet	getChannelLayout ()
	Get the channel layout of the audio stream.

Public Attributes
int64	startInSamples = 0
	The starting point of the reader in playback samples.
Public Attributes inherited from AudioFormatReader
double	sampleRate = 0
	The sample-rate of the stream.
unsigned int	bitsPerSample = 0
	The number of bits per sample, e.g.
int64	lengthInSamples = 0
	The total number of samples in the audio stream.
unsigned int	numChannels = 0
	The total number of channels in the audio stream.
bool	usesFloatingPointData = false
	Indicates whether the data is floating-point or fixed.
StringPairArray	metadataValues
	A set of metadata values that the reader has pulled out of the stream.
InputStream *	input
	The input stream, for use by subclasses.

Additional Inherited Members
Protected Member Functions inherited from AudioFormatReader
	AudioFormatReader (InputStream *sourceStream, const String &formatName)
	Creates an AudioFormatReader object.
Static Protected Member Functions inherited from AudioFormatReader
static void	clearSamplesBeyondAvailableLength (int *const *destChannels, int numDestChannels, int startOffsetInDestBuffer, int64 startSampleInFile, int &numSamples, int64 fileLengthInSamples)
	Used by AudioFormatReader subclasses to clear any parts of the data blocks that lie beyond the end of their available length.

Detailed Description

Subclass of AudioFormatReader that reads samples from a group of playback regions.

Plug-Ins typically use this to draw the output of a playback region in their UI.

In order to read from playback regions, the reader requires an audio processor that acts as ARA playback renderer. Configuring the audio processor for real-time operation results in the reader being real-time capable too, unlike most other AudioFormatReaders. The reader instance will take care of adding all regions being read to the renderer and invoke its processBlock function in order to read the region samples.

The reader becomes invalid if

• any region properties are updated in a way that would affect its samples,
• any region content is updated in a way that would affect its samples, or
• any of its regions are destroyed.

Constructor & Destructor Documentation

ARAPlaybackRegionReader() [1/2]

ARAPlaybackRegionReader::ARAPlaybackRegionReader ( ARAPlaybackRegion * playbackRegion )

explicit

Create an ARAPlaybackRegionReader instance to read the given playbackRegion, using the sample rate and channel count of the underlying ARAAudioSource.

Parameters

playbackRegion

The playback region that should be read - must not be nullptr!

ARAPlaybackRegionReader() [2/2]

ARAPlaybackRegionReader::ARAPlaybackRegionReader	(	double	sampleRate,
		int	numChannels,
		const std::vector< ARAPlaybackRegion * > &	playbackRegions )

Create an ARAPlaybackRegionReader instance to read the given playbackRegions.

Parameters

sampleRate	The sample rate that should be used for reading.
numChannels	The channel count that should be used for reading.
playbackRegions	The vector of playback regions that should be read - must not be empty! All regions must be part of the same ARADocument.

~ARAPlaybackRegionReader()

ARAPlaybackRegionReader::~ARAPlaybackRegionReader ( )

override

Member Function Documentation

isValid()

bool ARAPlaybackRegionReader::isValid

(

)

const

Returns true as long as any of the reader's underlying playback region's haven't changed.

invalidate()

void ARAPlaybackRegionReader::invalidate

(

)

Invalidate the reader - this should be called if the sample content of any of the reader's ARAPlaybackRegions changes.

readSamples()

bool ARAPlaybackRegionReader::readSamples ( int *const * destChannels, int numDestChannels, int startOffsetInDestBuffer, int64 startSampleInFile, int numSamples )

overridevirtual

Subclasses must implement this method to perform the low-level read operation.

Callers should use read() instead of calling this directly.

Parameters

destChannels	the array of destination buffers to fill. Some of these pointers may be null
numDestChannels	the number of items in the destChannels array. This value is guaranteed not to be greater than the number of channels that this reader object contains
startOffsetInDestBuffer	the number of samples from the start of the dest data at which to begin writing
startSampleInFile	the number of samples into the source data at which to begin reading. This value is guaranteed to be >= 0.
numSamples	the number of samples to read

Implements AudioFormatReader.

willUpdatePlaybackRegionProperties()

void ARAPlaybackRegionReader::willUpdatePlaybackRegionProperties ( ARAPlaybackRegion * playbackRegion, ARAPlaybackRegion::PropertiesPtr newProperties )

overridevirtual

Called before the playback region's properties are updated.

Parameters

playbackRegion	The playback region whose properties will be updated.
newProperties	The playback region properties that will be assigned to playbackRegion.

Reimplemented from ARAPlaybackRegionListener.

didUpdatePlaybackRegionContent()

void ARAPlaybackRegionReader::didUpdatePlaybackRegionContent ( ARAPlaybackRegion * playbackRegion, ARAContentUpdateScopes scopeFlags )

overridevirtual

Called when the playback region's content (i.e.

samples or notes) changes.

Parameters

playbackRegion	The playback region with updated content.
scopeFlags	The scope of the content update.

Reimplemented from ARAPlaybackRegionListener.

willDestroyPlaybackRegion()

void ARAPlaybackRegionReader::willDestroyPlaybackRegion ( ARAPlaybackRegion * playbackRegion )

overridevirtual

Called before the playback region is destroyed.

Parameters

playbackRegion

The playback region that will be destroyed.

Reimplemented from ARAPlaybackRegionListener.

Member Data Documentation

startInSamples

int64 ARAPlaybackRegionReader::startInSamples = 0

The starting point of the reader in playback samples.