Class AudioContext

Provides methods to instantiate, use and destroy an audio context for playback. Static methods are provided to list available devices known by the driver.

Inheritance

Object

AudioContext

Implements

IDisposable

Inherited Members

Object.Equals(Object, Object)

Object.ReferenceEquals(Object, Object)

Object.GetType()

Object.MemberwiseClone()

Namespace: OpenTK.Audio

Assembly: OpenTK.dll

Syntax

public sealed class AudioContext : IDisposable

Constructors

AudioContext()

Constructs a new AudioContext, using the default audio device.

Declaration

public AudioContext()

AudioContext(String)

Constructs a new AudioContext instance.

Declaration

public AudioContext(string device)

Parameters

Type	Name	Description
String	device	The device name that will host this instance.

AudioContext(String, Int32)

Constructs a new AudioContext, using the specified audio device and device parameters.

Declaration

public AudioContext(string device, int freq)

Parameters

Type	Name	Description
String	device	The name of the audio device to use.
Int32	freq	Frequency for mixing output buffer, in units of Hz. Pass 0 for driver default.

Remarks

Use AudioContext.AvailableDevices to obtain a list of all available audio devices. devices.

AudioContext(String, Int32, Int32)

Constructs a new AudioContext, using the specified audio device and device parameters.

Declaration

public AudioContext(string device, int freq, int refresh)

Parameters

Type	Name	Description
String	device	The name of the audio device to use.
Int32	freq	Frequency for mixing output buffer, in units of Hz. Pass 0 for driver default.
Int32	refresh	Refresh intervals, in units of Hz. Pass 0 for driver default.

Remarks

Use AudioContext.AvailableDevices to obtain a list of all available audio devices. devices.

AudioContext(String, Int32, Int32, Boolean)

Constructs a new AudioContext, using the specified audio device and device parameters.

Declaration

public AudioContext(string device, int freq, int refresh, bool sync)

Parameters

Type	Name	Description
String	device	The name of the audio device to use.
Int32	freq	Frequency for mixing output buffer, in units of Hz. Pass 0 for driver default.
Int32	refresh	Refresh intervals, in units of Hz. Pass 0 for driver default.
Boolean	sync	Flag, indicating a synchronous context.

Remarks

Use AudioContext.AvailableDevices to obtain a list of all available audio devices. devices.

AudioContext(String, Int32, Int32, Boolean, Boolean)

Creates the audio context using the specified device and device parameters.

Declaration

public AudioContext(string device, int freq, int refresh, bool sync, bool enableEfx)

Parameters

Type	Name	Description
String	device	The device descriptor obtained through AudioContext.AvailableDevices.
Int32	freq	Frequency for mixing output buffer, in units of Hz. Pass 0 for driver default.
Int32	refresh	Refresh intervals, in units of Hz. Pass 0 for driver default.
Boolean	sync	Flag, indicating a synchronous context.
Boolean	enableEfx	Indicates whether the EFX extension should be initialized, if present.

Remarks

For maximum compatibility, you are strongly recommended to use the default constructor.

Multiple AudioContexts are not supported at this point.

The number of auxilliary EFX sends depends on the audio hardware and drivers. Most Realtek devices, as well as the Creative SB Live!, support 1 auxilliary send. Creative's Audigy and X-Fi series support 4 sends. Values higher than supported will be clamped by the driver.

Exceptions

Type	Condition
ArgumentNullException	Occurs when the device string is invalid.
ArgumentOutOfRangeException	Occurs when a specified parameter is invalid.
AudioDeviceException	Occurs when the specified device is not available, or is in use by another program.
AudioContextException	Occurs when an audio context could not be created with the specified parameters.
NotSupportedException	Occurs when an AudioContext already exists.

AudioContext(String, Int32, Int32, Boolean, Boolean, AudioContext.MaxAuxiliarySends)

Creates the audio context using the specified device and device parameters.

Declaration

public AudioContext(string device, int freq, int refresh, bool sync, bool enableEfx, AudioContext.MaxAuxiliarySends efxMaxAuxSends)

Parameters

Type	Name	Description
String	device	The device descriptor obtained through AudioContext.AvailableDevices.
Int32	freq	Frequency for mixing output buffer, in units of Hz. Pass 0 for driver default.
Int32	refresh	Refresh intervals, in units of Hz. Pass 0 for driver default.
Boolean	sync	Flag, indicating a synchronous context.
Boolean	enableEfx	Indicates whether the EFX extension should be initialized, if present.
AudioContext.MaxAuxiliarySends	efxMaxAuxSends	Requires EFX enabled. The number of desired Auxiliary Sends per source.

Remarks

For maximum compatibility, you are strongly recommended to use the default constructor.

Multiple AudioContexts are not supported at this point.

The number of auxilliary EFX sends depends on the audio hardware and drivers. Most Realtek devices, as well as the Creative SB Live!, support 1 auxilliary send. Creative's Audigy and X-Fi series support 4 sends. Values higher than supported will be clamped by the driver.

Exceptions

Type	Condition
ArgumentNullException	Occurs when the device string is invalid.
ArgumentOutOfRangeException	Occurs when a specified parameter is invalid.
AudioDeviceException	Occurs when the specified device is not available, or is in use by another program.
AudioContextException	Occurs when an audio context could not be created with the specified parameters.
NotSupportedException	Occurs when an AudioContext already exists.

Properties

AvailableDevices

Returns a list of strings containing all known playback devices.

Declaration

public static IList<string> AvailableDevices { get; }

Property Value

Type	Description
IList<String>

CurrentContext

Gets the OpenTK.Audio.AudioContext which is current in the application.

Declaration

public static AudioContext CurrentContext { get; }

Property Value

Type	Description
AudioContext

Remarks

Only one AudioContext can be current in the application at any time, regardless of the number of threads.

CurrentDevice

Gets a System.String with the name of the device used in this context.

Declaration

public string CurrentDevice { get; }

Property Value

Type	Description
String

CurrentError

Returns the ALC error code for this instance.

Declaration

public AlcError CurrentError { get; }

Property Value

Type	Description
AlcError

DefaultDevice

Returns the name of the device that will be used as playback default.

Declaration

public static string DefaultDevice { get; }

Property Value

Type	Description
String

IsProcessing

Gets a System.Boolean indicating whether the AudioContext is currently processing audio events.

Declaration

public bool IsProcessing { get; }

Property Value

Type	Description
Boolean

See Also

Process()

Suspend()

IsSynchronized

Gets a System.Boolean indicating whether the AudioContext is synchronized.

Declaration

public bool IsSynchronized { get; }

Property Value

Type	Description
Boolean

See Also

Process()

Methods

CheckErrors()

Checks for ALC error conditions.

Declaration

public void CheckErrors()

Exceptions

Type	Condition
OutOfMemoryException	Raised when an out of memory error is detected.
AudioValueException	Raised when an invalid value is detected.
AudioDeviceException	Raised when an invalid device is detected.
AudioContextException	Raised when an invalid context is detected.

Dispose()

Disposes of the AudioContext, cleaning up all resources consumed by it.

Declaration

public void Dispose()

Equals(Object)

Compares this instance with another.

Declaration

public override bool Equals(object obj)

Parameters

Type	Name	Description
Object	obj	The instance to compare to.

Returns

Type	Description
Boolean	True, if obj refers to this instance; false otherwise.

Overrides

Object.Equals(Object)

Finalize()

Finalizes this instance.

Declaration

protected void Finalize()

GetHashCode()

Calculates the hash code for this instance.

Declaration

public override int GetHashCode()

Returns

Type	Description
Int32

Overrides

Object.GetHashCode()

MakeCurrent()

Makes the AudioContext current in the calling thread.

Declaration

public void MakeCurrent()

Remarks

Only one AudioContext can be current in the application at any time, regardless of the number of threads.

Exceptions

Type	Condition
ObjectDisposedException	Occurs if this function is called after the AudioContext has been disposed.
AudioContextException	Occurs when the AudioContext could not be made current.

Process()

Processes queued audio events.

Declaration

public void Process()

Remarks

If AudioContext.IsSynchronized is true, this function will resume the internal audio processing thread. If AudioContext.IsSynchronized is false, you will need to call this function multiple times per second to process audio events.

In some implementations this function may have no effect.

Exceptions

Type	Condition
ObjectDisposedException	Occurs when this function is called after the AudioContext had been disposed.

See Also

Suspend()

IsProcessing

IsSynchronized

SupportsExtension(String)

Checks whether the specified OpenAL extension is supported.

Declaration

public bool SupportsExtension(string extension)

Parameters

Type	Name	Description
String	extension	The name of the extension to check (e.g. "ALC_EXT_EFX").

Returns

Type	Description
Boolean	true if the extension is supported; false otherwise.

Suspend()

Suspends processing of audio events.

Declaration

public void Suspend()

Remarks

To avoid audio artifacts when calling this function, set audio gain to zero before suspending an AudioContext.

In some implementations, it can be faster to suspend processing before changing AudioContext state.

In some implementations this function may have no effect.

Exceptions

Type	Condition
ObjectDisposedException	Occurs when this function is called after the AudioContext had been disposed.

See Also

Process()

IsProcessing

IsSynchronized

ToString()

Returns a String that desrcibes this instance.

Declaration

public override string ToString()

Returns

Type	Description
String	A String that desrcibes this instance.

Overrides

Object.ToString()

Implements

System.IDisposable