Alright, just tried No.Ordinary.Family.S01E07.HDTV.XviD-LOL.avi and I gotta say wow. It runs great, subs are very good readable. For vids on the go it's great (maybe not on a DS Phat, but I imagine it very good on a DSi XL).
This may be a noob question but....it says no conversion required but what if you video size is larger than the DS screen? Like if ure video size is 500x500 but the DS screen is i think 256x192 what will happen then.