screen flickers when playing mpeg movie

[khallebal]

the screen goes crazy as if you gave it a higher resolution that it can not support(i had to use a shortcut to close mediaplayer) ,this prob existed since R1A1,but playing it with vlc goes smooth,this prob occurs only with MPEG file format,not with AVI and it doesn't matter wich encoding,i got this prob with mpeg1,mpeg4 and mp4 files,this doesn't happen on another machine,it could be related to the intel extreme driver,because haiku detects my 15" monitor as a 13.1" and it gives it a 640x480 resolution,but when i change the resolution to 800x600 it generates a vesa file in the settings with that resolution.if you need more info just ask.