final cut and imovie can directly address cameras and bypass quicktime ...
so you cant guarantee this.
none of the eyetv products had quicktime drivers last time i checked. totally proprietary.
security spy usually has best video digitiser links:
http://www.bensoftware.com/ss/instal...usbinputs.html
it lists some usb composite devices- they indicate a 3rd party driver is required
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decklink also have this:
http://www.decklink.com/products/videorecorder/
but i dont know whether its only proprietary