I would like to have that ‘algolith” as well.
I think that to blow an image up, is one of the worst thing can ever be done to the poor image. And 1.33 is not an small blow-up. How ever if is not any other solution, (and there is not in this case: From 16×9 to 4×3) there are some filters and plugins to help to get a better result (I’ve never try them). But if you don’t want to expend extra money, try to use the features that the applications offer. When ever I have to resize something I do it with Shake. Shake uses diferent filters for resizing up or down the image. I think that AE7 offer as well diferent filter taht you can chose for this task. Motion include a high quality filter calls Lanczos (that is also included in Shake) but is for resizing down. FC, for example,do not offer this chance, but at least offer you the oportunity of a “Better” rendering when there is a motion transformation (resizing, repositioning, etc).
Salud,
Rafael