How to compile MPlayer with support for dvdnav:

Since the versions of dvdnav and dvdread generally shipped with most Linux
distributions are outdated and unmaintained remove any traces of dvdnav and
dvdread from your computer (something like the command below should suffice):
$ rm -rf /usr/lib/libdvdnav* /usr/lib/libdvdread* /usr/include/dvdnav* \
         /usr/include/dvdread* /usr/local/lib/libdvdnav* \
         /usr/local/lib/libdvdread* /usr/local/include/dvdnav* \
         /usr/local/include/dvdread* /usr/bin/dvdnav-config \
         /usr/local/bin/dvdnav-config

Now download dvdnav from MPHQ (dvdnav includes its own version of dvdread):
$ svn co svn://svn.mplayerhq.hu/dvdnav/trunk/libdvdnav libdvdnav
$ cd libdvdnav
$ ./autogen.sh && ./configure && make
(or, if you feel brave and want to help us improve the new build system)
$ ./configure2 && make
install it as root with
$ make install

From within the MPlayer source tree run
$ ./configure --disable-dvdread-internal
followed by your preferred parameters.
Be warned that you *MUST* disable MPlayer's internal copy of dvdread or something
- most likely - won't work as expected (if at all).
After configure is run it should say that support for dvdnav and dvdread was
enabled. If not, investigate the dvdnav and dvdread sections in configure.log
and try to understand what went wrong. If you can't solve the problem yourself
post the two sections to mplayer-users.

Notice: Audio and subtitle language selection by means of menus doesn't work yet.
Nonetheless they can be switched as usual at any time during
playback by pressing '#' and 'j' (or the keys you chose to override those two
bindings).