When we use the zoom tool on a video clip it's immediately apparent that the more you move in with your zooming that the quality of the vision you are left with quickly diminishes. Since the image size of 720 x 576 (Pal) is quite small to start with, everything should be done to maintain the quality of the original.
I know that when dealing with still images, any lab that wants to blow up a photo to poster size will employ extra software to assist in this regard. Is there some program plug in available for video similar to Lizartech's 'Genuine Factals' which is used for stills available to help do this?