What did you do? Upscale? You say your source is DVD but then go on to say you are encoding at iPad resolution, which is 1024*(aspectratio). DVD's are better off not being upscaled. If you use a source which is HD, then of-course use the 1024*(aspectratio) to get max quality for the screen size. Up to 1280x720 is supported, but you can cut corners to save on file size.