Mark, Okay thanks, I was not aware of that being a standard trick.  I'm curious how far one can push this - can you double the linear frame dimensions (i.e. 4x the frame area)?  Also, I wonder if that's more or less what happens when my 720x480 animations are shown on the same large movie screens as the live action HD entries ... altho I confess I don't know how they are projected, I'm just glad they look reasonable.