It's a shame that the 5310XM can't play QVGA videos, although the screen has such size. I've been posting a topic for help regarding the similar problem I've met, weeks ago, but got no replies, therefore I'm adding this new topic to make it a bump.
I believe that the phone, actually, can play QVGA videos, since the size of the screen is large enough to make it. Maybe (I'm not even sure about that) the phone can't play such videos because the camera can't take QVGA videos, I guess. But anyway, this phone can run Java applications with QVGA resolution and (most probably) same is possible for the media player. Is that just a trick made by the designer? Are there any Java applications which can play QVGA videos (in fullscreen mode) available? I'll wait for replies, thanks.