gets an access to internal object. Required "device_sharing" feature disable for correct work.
For Blackmagic devices the 1st parameter is ignored. The method returns IDeckLinkInput (MFLive) / IDeckLinkOutput (MFRenderer) object (information about these interfaces is placed into Decklink SDK documentation)

Public Overridable Sub DeviceGetInternal( _
   ByVal _eDevType As eMFDeviceType, _
   ByRef _ppObject As Object _
) 

public virtual void DeviceGetInternal( 
   eMFDeviceType _eDevType,
   out object _ppObject
)

public procedure DeviceGetInternal( 
    _eDevType: eMFDeviceType;
   Out  _ppObject: TObject
); virtual; 

public: virtual void DeviceGetInternal( 
   eMFDeviceType _eDevType,
   [PARAMFLAG::Out] IUnknown* _ppObject
) 

object screenCapture;
m_objLive.DeviceGetInternal(eMFDeviceType.eMFDT_Video, out screenCapture);