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PKEY_AudioEndpoint_GUID Property

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PKEY_AudioEndpoint_GUID Property

The PKEY_AudioEndpoint_GUID property supplies the DirectSound device identifier that corresponds to the audio endpoint device. The property value is a GUID that the client can supply as the device identifier to the DirectSoundCreate or DirectSoundCaptureCreate function in the DirectSound API. This value uniquely identifies the audio endpoint device across all audio endpoint devices in the system. For more information about DirectSound, see the DirectX SDK documentation.

The vt member of the PROPVARIANT structure is set to VT_LPWSTR.

The pwszVal member of the PROPVARIANT structure points to a null-terminated, wide-character string that contains a GUID that identifies the audio endpoint device in DirectSound.

As explained previously, the MMDevice API supports device roles. Although DirectSound does not directly support device roles, a DirectSound client can use the PKEY_AudioEndpoint_GUID property to select a DirectSound rendering or capture device based on its device role.

For example, a DirectSound application performs the following steps to create a DirectSound device that corresponds to the rendering endpoint device that the user has assigned the eMultimedia role to:

  1. Call the IMMDeviceEnumerator::GetDefaultAudioEndpoint method to get the IMMDevice interface of the rendering endpoint device that has the eMultimedia role.
  2. Call the IMMDevice::OpenPropertyStore method to obtain the IPropertyStore interface of the eMultimedia device. For more information about IPropertyStore, see the Windows SDK documentation.
  3. Call the IPropertyStore::GetValue method to obtain the PKEY_AudioEndpoint_GUID property value.
  4. Convert the property value from a GUID in string format to a 16-byte GUID structure.
  5. Call the DirectSoundCreate function with the GUID to create the device with the eMultimedia role.

Note that the 16-byte GUID generated in step 4 matches the device GUID that identifies the device during DirectSound device enumeration. The DirectSoundEnumerate function enumerates rendering endpoint devices, and the DirectSoundCaptureEnumerate function enumerates capture endpoint devices. In either case, the device GUID is the first parameter passed to the enumeration callback function. For more information about DirectSound enumeration, see the DirectX SDK documentation.

For a code example that uses the PKEY_AudioEndpoint_GUID property, see Device Roles for DirectSound Applications.

Requirements

Client: Windows Vista

Header: Include Mmdeviceapi.h.

See Also

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