Divx on HD TV questions

[Alacard]

I have a few general questions about Divx encoded material. I have a 53" NON-HD sony big screen and an LG LDA-511 dvd/divx player. When playing divx movies on this TV, the divx movies look great. Couldn't be happier. However... when playing the same movies on a Pioneer Plasma and a JVC lcd TV, the Divx and Xvid movies are blocky and look much worse than on my standard tv. Is this normal? One of the movies..for example.. was ripped from DVD and was approx 1.4gig in size.

I'm considering converting a lot of my episode DVD's to Divx, but if this blocky look is normal on HD TV's, I might change my mind. If this is the wrong forum, please move to the correct one. Thanks.

[mic]

Very generally a TV is designed to play 720 x 480/576 video. Other displays (like HDTV) might use a larger frame size. If you take a 320 x 240 divx file that looks good playing on your PC at orig size, how does it look full screen? To my knowledge only way around this sort of thing, regardless format, is upsampling player or larger videos.