Async::AudioFilter Class Reference

A class for creating a wide range of audio filters. More...

#include <AsyncAudioFilter.h>

Inheritance diagram for Async::AudioFilter:

Public Member Functions
	AudioFilter (int sample_rate=INTERNAL_SAMPLE_RATE)
	Constuctor.
	AudioFilter (const std::string &filter_spec, int sample_rate=INTERNAL_SAMPLE_RATE)
	Constuctor.
	~AudioFilter (void)
	Destructor.
bool	parseFilterSpec (const std::string &filter_spec)
	Create the filter from the given filter specification.
std::string	errorString (void) const
	Get the latest filter creation error.
void	setOutputGain (float gain_db)
	Set the output gain of the filter.
void	reset (void)
	Reset the filter state.
Public Member Functions inherited from Async::AudioProcessor
	AudioProcessor (void)
	Default constuctor.
virtual	~AudioProcessor (void)
	Destructor.
int	writeSamples (const float *samples, int len)
	Write audio to the filter.
void	flushSamples (void)
	Order a flush of all samples.
void	resumeOutput (void)
	Resume output to the sink if previously stopped.
void	allSamplesFlushed (void)
	All samples have been flushed by the sink.
Public Member Functions inherited from Async::AudioSink
	AudioSink (void)
	Default constuctor.
virtual	~AudioSink (void)
	Destructor.
bool	registerSource (AudioSource *source)
	Register an audio source to provide samples to this sink.
void	unregisterSource (void)
	Unregister the previously registered audio source.
bool	isRegistered (void) const
	Check if an audio source has been registered.
AudioSource *	source (void) const
	Get the registered audio source.
Public Member Functions inherited from Async::AudioSource
	AudioSource (void)
	Default constuctor.
virtual	~AudioSource (void)
	Destructor.
bool	registerSink (AudioSink *sink, bool managed=false)
	Register an audio sink to provide samples to.
void	unregisterSink (void)
	Unregister the previously registered audio sink.
bool	isRegistered (void) const
	Check if an audio sink has been registered.
AudioSink *	sink (void) const
	Get the registered audio sink.
bool	sinkManaged (void) const
	Check if the sink is managed or not.
void	handleAllSamplesFlushed (void)
	The registered sink has flushed all samples.

Protected Member Functions
void	processSamples (float *dest, const float *src, int count)
	Process incoming samples and put them into the output buffer.
Protected Member Functions inherited from Async::AudioProcessor
void	setInputOutputSampleRate (int input_rate, int output_rate)
	Set the input and output sample rates.
Protected Member Functions inherited from Async::AudioSink
void	sourceResumeOutput (void)
	Tell the source that we are ready to accept more samples.
void	sourceAllSamplesFlushed (void)
	Tell the source that all samples have been flushed.
bool	setHandler (AudioSink *handler)
	Setup another sink to handle the incoming audio.
void	clearHandler (void)
	Clear a handler that was previously setup with setHandler.
AudioSink *	handler (void) const
Protected Member Functions inherited from Async::AudioSource
int	sinkWriteSamples (const float *samples, int len)
void	sinkFlushSamples (void)
bool	setHandler (AudioSource *handler)
	Setup another source to handle the outgoing audio.
AudioSource *	handler (void) const
void	clearHandler (void)
	Clear a handler that was previously setup with setHandler.

Detailed Description

A class for creating a wide range of audio filters.

Author

Tobias Blomberg / SM0SVX

Date

2006-04-23

Definition at line 113 of file AsyncAudioFilter.h.

Constructor & Destructor Documentation

AudioFilter() [1/2]

Async::AudioFilter::AudioFilter ( int sample_rate = INTERNAL_SAMPLE_RATE )

explicit

Constuctor.

Parameters

sample_rate

The sampling rate

AudioFilter() [2/2]

Async::AudioFilter::AudioFilter ( const std::string & filter_spec, int sample_rate = INTERNAL_SAMPLE_RATE )

explicit

Constuctor.

Parameters

filter_spec	The filter specification
sample_rate	The sampling rate

Use this constructor to set up at filter and call parseFilterSpec on the given filter specification. If the filter creation fails, this function will do an "exit(1)".

~AudioFilter()

Async::AudioFilter::~AudioFilter

(

void

)

Destructor.

Member Function Documentation

errorString()

std::string Async::AudioFilter::errorString ( void ) const

inline

Get the latest filter creation error.

Returns

Returns an error string if an error has occured previously

If the parseFilterSpec function return false, this function can be used to retrieve an error text describing the error.

Definition at line 158 of file AsyncAudioFilter.h.

parseFilterSpec()

bool Async::AudioFilter::parseFilterSpec

(

const std::string &

filter_spec

)

Create the filter from the given filter specification.

Parameters

filter_spec

The filter specification

Returns

Returns true on success or else false

If using the constructor where a filter specification string is not given, use this function to set up the filter. This function may be called multiple times to change the filter without creating a new filter object.

processSamples()

void Async::AudioFilter::processSamples ( float * dest, const float * src, int count )

protectedvirtual

Process incoming samples and put them into the output buffer.

Parameters

dest	Destination buffer
src	Source buffer
count	Number of samples in the source buffer

This function is called from the base class to do the actual processing of the incoming samples. All samples must be processed, otherwise they are lost and the output buffer will contain garbage.

Implements Async::AudioProcessor.

reset()

void Async::AudioFilter::reset

(

void

)

Reset the filter state.

setOutputGain()

void Async::AudioFilter::setOutputGain

(

float

gain_db

)

Set the output gain of the filter.

Parameters

gain_db

The gain to set in dB

Use this function to apply a gain (positive) or attenuation (negative) after the filter output. A gain of 6dB will amplify the signal with a factor of two.

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

• AsyncAudioFilter.h