[jitter] Smoother look

Dear Reader, 

I have got a video which I loader into Jitter. It is 640 x 480. Because the low resolution, the full screen projection looks very bad. If I just change the resolution of the jit.matrix or the jit.op. .... these will not help. 
 My query is about how you would make the screen look smoother, which objects could i use to make the video look better, after I changed the output to a higher resolution?

All help appreciated, 
all the best, 

tEdor