DVD Player, included with Mac OS X, can be used to watch DVD movies on your computer. You can watch movies recorded on standard DVD-video discs or you can view DVD projects that are stored on your hard disk.
DVD Player can play HD DVD discs that were authored using Apple's DVD Studio Pro.
Note: DVD Player cannot play HD DVD discs that were not authored in DVD Studio Pro, even if a compatible HD DVD drive is connected to, or installed in, your computer.