I recently purchased an hd movie from itunes and when i play it on my 6 month old macbook, it doesnt sync, the movement is jumpy and the sound is not syncing to the lip movement. I contacted itunes and they had me update my software and redownload the movie. Its still doing it. Non hd movies work fine. Is this something a macbook can't handle or is the movie thats the issue. Thanks for any help!