Choppy video?

The other evening, I wanted to watch a movie. It so happens that I had a few movies on my iBook that I purchased from the iTunes store: Rocky and Rocky II. I settled down to watch Rocky (which I have seen several times before) and, much to my dismay, the video was choppy. No matter what I did with various settings, it remained choppy. There were moments of smoothness, followed by seemingly longer moments of choppiness. It was very frustrating. So I did what any geek would do, I did a google search for choppy video in iTunes. I came up with lots of hits, most of which were complaints about iTunes 7, none of which suggested practical solutions. (More memory, some suggested. No more memory, others insisted.)

Well, I had fooled around with just about every setting I could think of. I was attempting to watch the movie in bed and so I started to think about anything that I hadn’t tried yet. I was about 30 minutes into the movie, when I noticed that I had about 1 hour of battery life left. That made me curious. Could the problem be that the onboard video card was not getting enough power? So I plugged in my iBook and resume the movie and the choppiness went away.

In fact, after that I experimented. When the laptop was plugged into the AC, there was no choppiness in video playback, but when it was not plugged in, the choppiness was obvious. What I thought was strange about this was not the difference in power provided by battery versus AC, but the fact that this solution wasn’t reported on any of the searches that I did.

Can anyone (perhaps kevnyc) explain why I’d get smooth video with the iBook plugged into the AC and choppy video when it was not plugged in? I’m curious…