Identifies the combination of audio devices that the application is currently using with the Voice Capture DSP.

Constant for IPropertyBag

Available only by using IPropertyStore.

Data Type


Applies To


Set this property if you are using the DSP in filter mode and the value of the MFPKEY_WMAAECMA_RETRIEVE_TS_STATS property is VARIANT_TRUE.

When the MFPKEY_WMAAECMA_RETRIEVE_TS_STATS property is VARIANT_TRUE, the DSP collects statistics about the time stamps from the audio devices and stores this information in the registry. These statistics can change for each combination of audio capture device and audio rendering device. Therefore, the application must assign a GUID to identify the particular combination of devices in use. The application should keep track of this GUID, so that it can assign the same GUID whenever it uses the same pair of audio devices.

If you are using the DSP in source mode, you do not need to set this property. The DSP automatically generates a GUID based on the value of the MFPKEY_WMAAECMA_DEVICE_INDEXES property.


Minimum supported client
Windows Vista [desktop apps only]
Minimum supported server
Windows Server 2008 [desktop apps only]

See also

Media Foundation Properties

Voice Capture DSP