Which is better DIVX or XviD when playing .avi file?

[adicoto]

:) Since Peter mentioned my name, I can't help. :)

So, if you want to play any file on a relatively slow computer, use FFDshow to decode (J7N will also recomend it) or XviD, with no post processing activated. Poor quality, but the files are running.

If you play DivX files using XviD decoder and vice-versa, if you want my opinion, haven't seen any difference. Just that DivX interface is more complex and let you alter some post processing options. In my case, brightness/contrast is the most important. Some builds of XviD didn't have this option, so I prefered DivX. But now I use DivX 5.xx to decode DivX 4 and newer, XviD to decode XviD encoded files and DivX 3.11 to decode older files.
So, try to use DivX as decoder and XviD as encoder.