[CentOS] Set default MPlayer -vo?

Hi,

I'm running CentOS 4.3 with the rpmforge and kbs repos enabled. I just installed MPlayer and tried it. It has a small problem.

When I want to view myfile.wmv, Mplayer displays the following error message: "Error opening/initialising the selected video_out (-vo) device."

So I opened a console, took a peek at the various options (mplayer -vo help), and then the movie worked just fine with mplayer -vo x11.

Q: how do I make this option my default, so that when I double-click on a .wmv or .avi in Nautilus, it gets opened with the -vo x11 option? I thought about creating an alias, but there must be some more orthodox way to do that.

Cheers,

Niki Kovacs