I watched some videos on my new macbook with quicktime player and realplayer and in both programs the videos are flickering. i checked on another apple computer if there was something wrong with the video files but they worked normally on the other one. i also tried to play the videos on itunes and it still was the same thing on my mac. i also noticed that if the video is a mp4 file there is no flickering. however for any other file it does. could anybody help me please?