Contains a caller-defined value for an METransformMarker event.
ULONG_PTR stored as UINT64
GUID MF_EVENT_MFT_CONTEXT = {0xb7cd31f1,0x899e,0x4b41,{0x80,0xc9,0x26,0xa8,0x96,0xd3,0x29,0x77} }
To get this attribute, call IMFAttributes::GetUINT64
To set this attribute, call IMFAttributes::SetUINT64
This attribute is used with the METransformMarker event. The value of the attribute is taken from the ulParam parameter of the IMFTransform::ProcessMessage method.
The GUID constant for this attribute is exported from mfuuid.lib.
Header: Declared in mfapi.h.