AudioSubsectionReader Class Reference

This class is used to wrap an AudioFormatReader and only read from a subsection of the file. More...

Inherits AudioFormatReader.

List of all members.

Public Member Functions
	AudioSubsectionReader (AudioFormatReader *sourceReader, int64 subsectionStartSample, int64 subsectionLength, bool deleteSourceWhenDeleted)
	Creates a AudioSubsectionReader for a given data source.
	~AudioSubsectionReader ()
	Destructor.
bool	readSamples (int **destSamples, int numDestChannels, int startOffsetInDestBuffer, int64 startSampleInFile, int numSamples)
	Subclasses must implement this method to perform the low-level read operation.
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.

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Detailed Description

This class is used to wrap an AudioFormatReader and only read from a subsection of the file.

So if you have a reader which can read a 1000 sample file, you could wrap it in one of these to only access, e.g. samples 100 to 200, and any samples outside that will come back as 0. Accessing sample 0 from this reader will actually read the first sample from the other's subsection, which might be at a non-zero position.

See also:

AudioFormatReader

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Constructor & Destructor Documentation

AudioSubsectionReader::AudioSubsectionReader	(	AudioFormatReader *	sourceReader,
		int64	subsectionStartSample,
		int64	subsectionLength,
		bool	deleteSourceWhenDeleted
	)

Creates a AudioSubsectionReader for a given data source.

Parameters:

	sourceReader	the source reader from which we'll be taking data
	subsectionStartSample	the sample within the source reader which will be mapped onto sample 0 for this reader.
	subsectionLength	the number of samples from the source that will make up the subsection. If this reader is asked for any samples beyond this region, it will return zero.
	deleteSourceWhenDeleted	if true, the sourceReader object will be deleted when this object is deleted.

AudioSubsectionReader::~AudioSubsectionReader

(

)

Destructor.

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Member Function Documentation

bool AudioSubsectionReader::readSamples	(	int **	destSamples,
		int	numDestChannels,
		int	startOffsetInDestBuffer,
		int64	startSampleInFile,
		int	numSamples
	)			[virtual]

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

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

Parameters:

	destSamples	the array of destination buffers to fill. Some of these pointers may be null
	numDestChannels	the number of items in the destSamples 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.

void AudioSubsectionReader::readMaxLevels	(	int64	startSample,
		int64	numSamples,
		float &	lowestLeft,
		float &	highestLeft,
		float &	lowestRight,
		float &	highestRight
	)			[virtual]

Finds the highest and lowest sample levels from a section of the audio stream.

This will read a block of samples from the stream, and measure the highest and lowest sample levels from the channels in that section, returning these as normalised floating-point levels.

Parameters:

	startSample	the offset into the audio stream to start reading from. It's ok for this to be beyond the start or end of the stream.
	numSamples	how many samples to read
	lowestLeft	on return, this is the lowest absolute sample from the left channel
	highestLeft	on return, this is the highest absolute sample from the left channel
	lowestRight	on return, this is the lowest absolute sample from the right channel (if there is one)
	highestRight	on return, this is the highest absolute sample from the right channel (if there is one)

See also:

read

Reimplemented from AudioFormatReader.

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

• juce_AudioSubsectionReader.h