If you want to do experiment you can try but i've try this my self with a pinnacle stick and it did not work , then i've tried with a Terratec Box and it did not work .... There might be a TV/Video input box out there working with with quick time but no one know.
on by the way it's not a catalyst issue , if the box work with Quick Time it work with catalyst , if doesn't work with Quick Time it doesn't work with catalyst.
Try searching for a Cheep box compatible with Quick time .
don't you have a Camcorder ?