Did you try installing from the PPA repository as described in the link I gave you? You shouldn't need to compile anything if you use those.
If you want to give compiling a shot, I'd suggest using the source from the mplayer2 site, then doing the following:
I didn't have auto* and libtool installed even after using build-dep, so I encountered some compiler errors along the way. Once I had all the tools, mplayer2 built pretty easily. It installs to /usr/local by default; the player is /usr/local/bin/mplayer. On my 64-bit machine /usr/local/bin is a symlink to /usr/local/bin32, which appears to be something that mplayer2 created during installation. bin32 has the same timestamp as mplayer.
sudo apt-get build-essential yasm git autogen autoconf automake libtool
sudo apt-get build-dep mplayer
tar xjvf mplayer2-build-2.0.tar.bz2
sudo make install