Render with quality in HD

when you up-scale or down-scale you add/remove pixels using algorithms. up-scaling you are adding data which was not present in the original. algorithm doesn't know that this was the face and what it should look like. All are just pixels. This is why up/down-scaled image or video may still look acceptable but it is physically impossible it could contain more details or look better than original. what was not present in the original will not magically reveal in the modified video unless you paint on it. this is why you should always aim your target. if you plan to make a dvd only - what is the use of shooting full hd?

true. that is why mpg are usually final files. but if i leave for myself a master file rendered with mpeg2 / hd / 50 Mbpsor even 25, and i cut out takes from it for another project, believe me - no one will know that this is the second generation...