If you want to view oculus Rift videos on Linux and display them on the Rift in an extended graphics mode you can use these options :

To send the video to the screen the Oculus Rift is connected to (generally -xineramascreen 1) :
-xineramascreen <0-...>
In Xinerama configurations (i.e. a single desktop that spans across multiple displays) this option tells MPlayer which screen to display movie on.

To prevent screen tearing :
Enables VBI for vesa.

To start the video in fullscreen mode :
Fullscreen playing (centers movie, and makes black bands around it). Toggle it with the 'f' key (not all video outputs support it). See also -zoom.

Example : mplayer -fs -vsync -xineramascreen 1 video.avi