Contains a pointer to the token that was provided to the IMFMediaStream::RequestSample method.
To get this attribute, call IMFAttributes::GetUnknown.
To set this attribute, call IMFAttributes::SetUnknown.
This attribute applies to media samples. The value of the attribute is the IUnknown pointer that is passed to the pToken parameter of the RequestSample method. The caller uses this attribute to track the status of the request.
If you are writing a custom media source, set this attribute on the sample when the media stream delivers a sample in response to the RequestSample method, unless the value of pToken is NULL.
The GUID constant for this attribute is exported from mfuuid.lib.
Minimum supported client
|Windows Vista [desktop apps | Windows Store apps]|
Minimum supported server
|Windows Server 2008 [desktop apps | Windows Store apps]|