IAudioAutoGainControl Interface
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IAudioAutoGainControl Interface
The IAudioAutoGainControl interface provides access to a hardware automatic gain control (AGC). The client obtains a reference to the IAudioAutoGainControl interface of a subunit by calling the IPart::Activate method with parameter refiid set to REFIID IID_IAudioAutoGainControl. The call to IPart::Activate succeeds only if the subunit supports the IAudioAutoGainControl interface. Only a subunit object that represents a hardware AGC function will support this interface.
Most Windows audio adapter drivers support the Windows Driver Model (WDM) and use kernel-streaming (KS) properties to represent the hardware control parameters in subunits (referred to as KS nodes). The IAudioAutoGainControl interface provides convenient access to the KSPROPERTY_AUDIO_AGC property of a subunit that has a subtype GUID value of KSNODETYPE_AGC. To obtain the subtype GUID of a subunit, call the IPart::GetSubType method. For more information about KS properties and KS node types, see the Windows DDK documentation.
IAudioAutoGainControl inherits from the IUnknown interface. In addition to the methods inherited from IUnknown, IAudioAutoGainControl supports the following methods.
| Method | Description |
| GetEnabled | Gets the current state (enabled or disabled) of the AGC. |
| SetEnabled | Enables or disables the AGC. |
Requirements
Client: Windows Vista
Header: Include Devicetopology.h.
See Also
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