No audio for some movies after upgrading to iTunes 11

I've ripped my DVD collection to my hard drive so I could use home sharing on all my apple tvs. I used handbrake on all of them, but now since upgrading to iTunes 11 several of the movies play with no audio. There were no issues prior to the upgrade. I would say it looks like 1 out of every 10 play with no audio. I really like iTunes 11 and I understand it will take a bit to work out the bugs, but is anyone else having this issue? I have a 2011 Mac mini and 2tb seagate external drive that only has my iTunes library on it. I'm relatively new to Mac, is there any way to access file info through iTunes or system preferences? Maybe I'm missing something easy? I really don't want to rip the movies again, it takes an hour per rip and I'd like to avoid that if possible. I have to be missing something though, right? How could a movie play fine prior to the upgrade, but after still play, but with no audio? Any help would be great. Thanks.