I believe that it will behave exactly as a non-copied DVD would. If you have an upconverting DVD player it would work the same algorithms on the picture of the burned DVD as it would the normal DVD. If it isn't upconverting, then your TV would attempt to scale it like it does with a normal DVD.
If you're talking about an otherwise downloaded movie, you would probably not see anything great. I know when I watch downloaded TV shows or movies streamed to my xbox 360 it doesn't look 1080p by any stretch...or really 480p in most cases.
I hope that helps, anyone can correct me if I'm misunderstanding the question
