Try PS3 Media Server program in Windows. I currently use it for my PS3 and my Samsung TV. It's a DLNA media server app but with transcoding on the fly support. It should allow even full HD videos on the N900 via transcoding on the fly. (even resize to non-HD) I haven't tried yet but I sure will when I get my N900.

http://ps3mediaserver.org/forum/view...php?f=2&t=3217