Keep mplayer open after video playback
Solution 1:
You can use this
#mplayer test.ogg -idle -fixed-vo
Solution 2:
You can do this with mplayer's slave mode. See:
http://www1.mplayerhq.hu/DOCS/tech/slave.txt
Also mentioned in the FAQ, 5th question under General Questions:
http://wiki.multimedia.cx/index.php?title=MPlayer_FAQ#General_Questions
Good luck!