When using DVI and some AMD/ATI graphics boards, the output gets scaled where the resolution or frequecy changes. Stupid ATI...

This script will detect a XBMC player start and force set scaling to zero on the DVI output to accieve true unscaled fullscreen. I made this fix when trying to get lovley and correct 24Hz refreshrate output.

player.py 

import xbmc
import xbmcgui
import subprocess
import os


class MyPlayer(xbmc.Player):
   def init (self): 
      xbmc.Player.init(self)


def onPlayBackStarted(self):
      if xbmc.Player().isPlayingVideo():
          os.system("~/.xbmc/scripts/scanset.sh &")


player=MyPlayer()
VIDEO = 0


while(1):
    if xbmc.Player().isPlaying():
        if xbmc.Player().isPlayingVideo():
        VIDEO = 1
    else:
        VIDEO = 0
    xbmc.sleep(1000)

Place in ~/.xbmc/scripts/. This also relies on scanset.sh script down below.

#!/bin/bash
sleep 3
echo "running aticonfig underscan-fix"
aticonfig --set-dispattrib=dfp1,positionX:0 >/dev/null
aticonfig --set-dispattrib=dfp1,positionY:0 >/dev/null
aticonfig --set-dispattrib=dfp1,sizeX:1920 >/dev/null
aticonfig --set-dispattrib=dfp1,sizeY:1080 >/dev/null
sleep 1