video files lagging in full screen stretch mode.

Hello I have encountered a problem with the video only being able to run smoothly unless it's displayed in the original ratio. I know the phone doesn't support 400X240 for videos like it should, but I would like to be able to at least stretch the video so it uses up the entire display. my question is what settings should be used(ex. bit rate, fps, resolution, whatever) in the conversion process so I can stretch the display without having to deal with the choppy playback. idk maybe there is a firmware update or something, if I can't watch a movie in full screen stretch whats the point in having a large screen?