If only one of the movies is causing this, it may be the way it was encoded, or the audio format isn't properly encoded as outlined in the manual's list of audio codecs that the television will support.
My husband and I just bought a Samsung 50 inch plasma model #PN50B450 and a Samsung Home Theatre System model #HTZ320. The HTS has a USB input that we used for our external hard drive that has some movies on it. The A/V is out of sync on only one of the movies, the rest play fine. Plus I started watching the movie on the computer to make sure it wasnt a bad copy and it plays fine on the computer. What could be causing the sync problems and is there a way to fix it?
Also, I tried adjusting the Speaker Delay Time with no luck as well as the AV Sync function which only made it worse. With the AV Sync set @ 0mSec the audio is still off by about 2 seconds and gets worse if I adjust it any further.
Another thing, when I first hook up the external hard drive and it starts to read it, there is a message at the top that says "Codec Not Supported." I didnt think that had anything to do with it since, like I said before, only 1 movie has the sync problem. Am I wrong in my assumption?