Installing MPlayer:

1) Log in as root. That means in YDL’s login menu your Username should be “root” and your password is the root password you typed during installation.

2) Launch Gnome Terminal. (Just like you did with VLC).

3) This time type: "yum install mplayer" hit Enter. (type "y" when prompted and hit Enter)

4) After the previous step finishes, Type "yum install mplayer-gui" hit Enter.

5) After process is complete, mplayer should be installed on your PS3.

Configuring, Launching and Using MPlayer:

MPlayer doesn't seem to pick the right drivers for the PS3 by default, so we are going to have to configure it.

NOTE: These configurations might not apply to everyone, I'm using a component cable, not HDMI.

1) Log in as root. Browse to /etc/mplayer and double click mplayer.conf. Make the changes shown in the pictures:

In video settings, vo=sdl
In audio settings, ao=sdl (Scroll down)

2) Once in GNOME (not as root), to launch MPlayer go to:
Applications ---> Sound & Video ---> MPlayer

3) Using MPlayer now should be easy, right click and check out the options.

4) If you pick a video and mplayer still fails to initialize, Open up a Terminal (we're still in Gnome) Applications ---> Accessories ---> Terminal

Type: "gmplayer -vo sdl" and hit enter. I only had to do this once. After that, MPlayer caught on.

5) To go to full screen, DON'T PRESS f, Press C. just trust me. To exit, press ESC

6) For further controls, check the MPlayer site: