I have an external Sony drx-510UL. When I play my official movies, they are very choppy (slowdowns, and choppy sounds, etc...). I then use dvd shrink on it and have an image on the hard drive. I then burn it onto a dvd-r, and pop it into the same drive. I can now watch the movie with no choppiness whatsoever. Does anyone know what the cause of this is? It doesn't make sense to me that a copy of something that doesn't work 100% works 100%.