revInitializeVideoGrabber questions

[Doug Lerner]

(1) In the docs, the revInitializeVideoGrabber command has just two
parameters, as in

revInitializeVideoGrabber "qt",iRect

However, in the actual sample stack provided there are three parameters, as
in

revInitializeVideoGrabber short name of this stack,"qt",iRect


What exactly is that first parameter used for?

(2) How can you detect that revInitializeVideoGrabber has been called and
thus does not need to be called again?

Thanks,


doug