A small percentage of iPads have had their video freeze, even through a reboot. One solution that might work is a "hard reset": hold the Home button and the sleep button for longer than it takes to get the Power Down slider. A few seconds later, it will reboot from scratch.
Also, there is some evidence it may be a hardware issue. But also that it does not happen if you don't leave the app in the middle of a video, but press Done before going to another app.
Why the iPad 2 may have super-resolution screen.
If an app is misbehaving and keeps doing so, it might help to plug in the 'pad and remove the app via iTunes. And then unplug it, and download the app again via the App Store from the iPad itself.
This just solved a problem with a fun app I have called Gravity Clock. As the second hand goes around, the numbers fall off and stack at the bottom. If you turn it around, the number debris will roll around like they are inside a box. Once, while demoing it, gravity was reversed, and they started falling up! And not collecting. Not as fun. But the tip above solved it.