I am having the same problem. It runs OK but every once in a while I get lines on the screen, and it's choppy. It's only for a second, but when you are watching a movie you can see every imperfection. I guess I'm picky. I really like Kaffeine's interface but Mplayer seems to play better.... anyway when I typed:
mplayer -vo xv filename.ext
I got this:
rzavarella@linux:~> mplayer -vo xv filename.ext
MPlayer 1.0pre6-3.3.4 (C) 2000-2004 MPlayer Team
CPU: Intel Pentium M Banias (Family: 6, Stepping: 5)
Detected cache-line size is 64 bytes
CPUflags: MMX: 1 MMX2: 1 3DNow: 0 3DNow2: 0 SSE: 1 SSE2: 1
Compiled with runtime CPU detection - WARNING - this is not optimal!
To get best performance, recompile MPlayer with --disable-runtime-cpudetection.
Failed to open /dev/rtc: Permission denied (it should be readable by the user.)
Opening joystick device /dev/input/js0
Can't open joystick device /dev/input/js0 : No such device
Can't init input joystick
Setting up LIRC support...
mplayer: could not connect to socket
mplayer: Permission denied
Failed to open LIRC support.
You will not be able to use your remote control.
File not found: 'filename.ext'
Failed to open filename.ext