IAudioPeakMeter Interface
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IAudioPeakMeter Interface
The IAudioPeakMeter interface provides access to a hardware peak-meter control. The client obtains a reference to the IAudioPeakMeter interface of a subunit by calling the IPart::Activate method with parameter refiid set to REFIID IID_IAudioPeakMeter. The call to IPart::Activate succeeds only if the subunit supports the IAudioPeakMeter interface. Only a subunit object that represents a hardware peak meter 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 IAudioPeakMeter interface provides convenient access to the KSPROPERTY_AUDIO_PEAKMETER property of a subunit that has a subtype GUID value of KSNODETYPE_PEAKMETER. 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.
IAudioPeakMeter inherits from the IUnknown interface. In addition to the methods inherited from IUnknown, IAudioPeakMeter supports the following methods.
| Method | Description |
| GetChannelCount | Gets the number of channels in the audio stream. |
| GetLevel | Gets the peak level that the peak meter recorded for the specified channel since the peak level for that channel was previously read. |
Requirements
Client: Windows Vista
Header: Include Devicetopology.h.
See Also
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