IAudioMidrange interface (devicetopology.h)
The IAudioMidrange interface provides access to a hardware midrange-level control. The client obtains a reference to the IAudioMidrange interface of a subunit by calling the IPart::Activate method with parameter refiid set to REFIID IID_IAudioMidrange. The call to IPart::Activate succeeds only if the subunit supports the IAudioMidrange interface. Only a subunit object that represents a hardware function for controlling the level of the mid-range frequencies in each channel will support this interface.
The IAudioMidrange interface provides per-channel controls for setting and getting the gain or attenuation level of the midrange frequencies in the audio stream. If a midrange-level hardware control can only attenuate the channels in the audio stream, then the maximum midrange level for any channel is 0 dB. If a midrange-level control can provide gain (amplification), then the maximum midrange level is greater than 0 dB.
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 IAudioMidrange interface provides convenient access to the KSPROPERTY_AUDIO_MID property of a subunit that has a subtype GUID value of KSNODETYPE_TONE. 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.
Inheritance
The IAudioMidrange interface inherits from the IPerChannelDbLevel interface.
Requirements
| Requirement | Value |
|---|---|
| Minimum supported client | Windows Vista [desktop apps only] |
| Minimum supported server | Windows Server 2008 [desktop apps only] |
| Target Platform | Windows |
| Header | devicetopology.h |