Actually, I think most of you don't know what he is asking or what you are talking about.
DVD's hold either ~4.5GB or ~9GB of data, while Blu-Ray holds ~25GB or ~50GB (single or dual layer for both formats). Both are capable of storing any kind of information you want (SD video, or HD video, SD graphics, or HD graphics in a game), however without Blu-Ray or some other kind of storage medium, you run out of space rather fast.
(widescreen) 480p = 720x480 = 345,600 pixels/frame
1080p = 1920x1080 = 2,073,600 pixels/frame
as you can see, 1080p has 6 times as many pixels/frame as a 480p image. To store all that extra data you need a lot more space. Sure, you can stick 10080p quality images on a DVD, but you will be able to put a lot more 1080p images on a Blu-Ray disc. Smaller disc space translates into shorter games and/or less information on the disc. Granted, compression techniques do exist, and you can sacrifice varying components to extend your games (reusing assets) but if you want a full length high quality movie image, you need the extra space.
In the end, you can make a DVD can do everything Blu-Ray can do, except at the cost of the quantity of content.