The problem is those mplayer binary packages is too old, for example, the ubuntu 12.04 LTS package in is built one year ago.
If I build newer mplayer myself, I system's package manager will think there is a broken dependency for smplayer.
So I have to build my own smplayer either. The home-made smplayer have not support for ubuntu's global menu.
I suggest remove the dependency for mplayer in smplayer's binary packages. In fact, as a program, smplayer will execute without mplayer.