I've actually managed to compile mplayer.28 for the 770. For some mysterious reason, the 'gmplayer' launched did not get built, but the mplayer binary did and it works decently in my 770 with OS2008HE (except that it crashes if I enable tearsync, no idea why!).

You can get get it at http://www.phys.ualberta.ca/~pbian/n770 if you want to try it. If anybody does, I'd be curious to see how it works for other people.

Bye & Good Luck!

Pablo B.