Stuttering play back on Ipod

I have really enjoyed Aharon Rabinowitz's podcasts on After Effects, and was quite glad when they started getting posted again regularly. I have learned a lot, and like having them on my Ipod for when I have a few min. of down time. They have all played back just fine until the last few months.

Usually it will playback fine through the opening title sequence, but once the tutorial actually starts, the video will freeze for a few seconds at a time, while the audio plays on. After a few seconds, the video will start playing again, jumping back into sync, then a few seconds later, it'll freeze again. The tutorials are still watchable, as Aharon is very detailed in his commentary, however it is quite annoying to say the least.

Like I said, this is a (sort of) recent development which I believe started with the March 30 Episode on creating a Heart Monitor. All of the previous episodes played back without a problem (Still do, in fact). I'm playing them on a new (4 months old) 80GB Ipod 5G. Any Ideas? is there something that changed with your video encoding around that time?

I'm just hoping that I can figure out a way to make the playback work
well, short of having to re-encode each episode.

Thanks,
Andrew.