Why does 5g video play movie in tiny window?

I have a 5g video ipod. Sometimes the movie plays in a tiny window on the side of the title and time. When this happens it is hard to correct it and I'm not sure why it happens or how to fix it.

 

Yes, That's what it looks like. I try to toggle the center button, but no change.

 

I am clicking from movies. It has always had this problem. The firmware was updated several months ago. Today I selected a movie with the center button and it worked fine. Later I forgot and selected a movie with the play button and it worked fine too, over and over. Most of my movies are handbrake encoded from dvd.

 

It has been restored a couple times in the last couple years with no change.

About the codec, even when a movie gives me trouble, it will either work next time or it worked before. I will check the tv-out.

Thanks everyone for your replies...