If you’re looking for mplayer + dvdnav support, there’s two ways to get it right now. Depending on how much support you want is going to change which ebuilds you’ll have to use right now, though.
If you just want simple playback support (no menu navigation), then use portage’s tree. Just unmask and emerge media-libs/libdvdnav, then re-emerge media-video/mplayer. That will build against the older, original dvdread library, but it should be enough to get you around the Sony ARccOS DRM. Hint: mplayer dvdnav://[track_number]
If you want the full playback + navigation support, you’re going to have to use an overlay (specifically, mine). I, personally, am against the idea of using overlays since I think it splits the tree, only asks for problems, and reminds me of using Mandrake back in the day when I had to have all these third-party mirrors just to get software I want. So, I’m really against the idea and wouldn’t be doing this unless there were an easier, simpler way.
Ranting aside, my overlay is at http://overlays.gentoo.org/dev/beandog Browse the ebuilds here. I would give some slick instructions on how to add it using layman, but since I never use overlays, I can’t tell you how, and I assume that the people who really know what they’re doing don’t need instructions anyway.
There are very few differences in my ebuilds. libdvdnav will use the newer version of libdvdread, so the one from the portage tree will show up as a blocker (and possibly break all your other packages that use it). After it’s installed, you’ll have to use my mplayer ebuild as well, since it’s configured to use the external dvdread library as well. After that, you can use dvdnav:// as you normally would. Hint: mplayer dvdnav://
I know it’s a bit of work, but until the forked libdvdnav can also work as a replacement or secondary slot to libdvdread in the tree, either option which would require testing, that’s how its gotta be. The plus side though is, it works.