I've been searching the web for days trying to figure this out, but almost every forum thread and web page that mentions these problems has to do with playing Bluray discs on a PC.
I've got a Samsung BD-6500 and there are a few movies that the player just has a horrible time with. One is Rio and another is The Lorax. The stuttering video/audio isn't constant, but it seems to get worse during musical scenes, which generally have a lot going on visually as well as with the audio.
Even the previews on The Lorax disc had trouble playing, and there were extended black pauses in between.
Where it's only specific movies, could it be a disc problem?
The player has the most recent firmware installed, which was released back in January.