gxAudioCard Class Reference

Writes audio data to a sound card . More...

#include <gxAudioCard.h>

List of all members.

Public Types
enum	state_t { STATE_CLOSED, STATE_OPEN, STATE_STARTED }
Public Member Functions
	gxAudioCard ()
virtual	~gxAudioCard ()
virtual int	write (float *samples, int sampleCount)=0
	Write some audio frames to the stream.
virtual bool	readyToWrite ()=0
	Always invoke readyToWrite and ensure it returns true before writing.
virtual bool	lookup (const char *driverName)=0
	Lookup the named device.
virtual int	open (int framesPerBuffer, int sampleRate)=0
	Opens the audio stream for output, but does not play sound.
virtual int	start ()=0
	Starts playing the sound.
virtual int	stop ()=0
	Stops playing the sound.
virtual int	close ()=0
	Close the audio stream.
virtual state_t	getState ()=0
	Get the card's state (closed, open, started).
virtual bool	isClockSource (gxAudioClockSource **sourceInterface)=0
	Specifies whether this filter is a clock source, and if so, provides a reference to the gxAudioClockSource interface implemented by this filter.

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Detailed Description

Writes audio data to a sound card .

.. so we can hear all this stuff.

To use this class, perform the following steps:

• Call lookupDevice, specifying the name of the sound card.
• Call openStream, specifying the sample rate and buffer size
• For event driven operation, call setEvent, specifying the object to be notified when the stream is ready to write
• Call startStream.
• (Possibly in another thread) wait on your notification event
• When event is signaled, check readyToWrite. If true..
• Call write, specifying the samples to be played.

TODO: fix up the result values from open,start,stop,close

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Member Enumeration Documentation

enum gxAudioCard::state_t

Enumerator: STATE_CLOSED  STATE_OPEN  STATE_STARTED

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Constructor & Destructor Documentation

gxAudioCard::gxAudioCard (   )  [inline]

virtual gxAudioCard::~gxAudioCard (   )  [inline, virtual]

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Member Function Documentation

virtual int gxAudioCard::close (   )  [pure virtual]

Close the audio stream.

virtual state_t gxAudioCard::getState (   )  [pure virtual]

Get the card's state (closed, open, started).

virtual bool gxAudioCard::isClockSource (  gxAudioClockSource **  sourceInterface  )  [pure virtual]

Specifies whether this filter is a clock source, and if so, provides a reference to the gxAudioClockSource interface implemented by this filter.

virtual bool gxAudioCard::lookup (  const char *  driverName  )  [pure virtual]

Lookup the named device. Returns true if the device exists. Otherwise returns false. TODO: Lookup device grabs some internal device info such as supported sample rates etc. Should add some accessors to allow application to retreive this information.

virtual int gxAudioCard::open (  int  framesPerBuffer, int  sampleRate )  [pure virtual]

Opens the audio stream for output, but does not play sound.

virtual bool gxAudioCard::readyToWrite (   )  [pure virtual]

Always invoke readyToWrite and ensure it returns true before writing.

virtual int gxAudioCard::start (   )  [pure virtual]

Starts playing the sound. Callbacks will be invoked, the notification event will be signaled periodically and writes will be allowed as audio data moves through the system.

virtual int gxAudioCard::stop (   )  [pure virtual]

Stops playing the sound.

virtual int gxAudioCard::write (  float *  samples, int  sampleCount )  [pure virtual]

Write some audio frames to the stream. "samples" is a pointer to the beginning of an array of interlaced audio samples. sampleCount indicates the number of samples in the array. Each frame contains one floating point number for each audio channel. So, for a stereo stream, the sample array will contain 2 x samplecount floating point numbers. After a successful write, the readyToWrite bit is false. Do not perform any more writes until readyToWrite becomes true. returns - the number of samples actually written

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

• gxAudioCard.h

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