Audio sync isues with itunes m4v purchased videos

[animematic]

So downloaded wreck it ralph from the iTunes store today an it plays but after a few minutes of watching I notice the video/audio starts to go out of sync the video moves slightly faster then the audio. If I stop and restart it fixes it but after a few minutes it happens again

 

[kenrivers]

These links from Apple communities may help:
https://discussions.apple.com/thread/2673011?start=0&tstart=0
http://support.apple.com/kb/TS1386 (Applies to Windows XP).
What OS and version of iTunes are you using?