AirPlay stops working when iPad screen blanks
I found that after upgrading my iPad 2 to iOS 5 and Apple TV to iOS 4.4 AirPlay video no longer continues in the background. When I move away from the iPad 2 app that is steaming to the TV or the iPad 2 locks itself (screen blanks), the Apple TV stops playing the video. This worked fine before the iOS updates.
AppleTV 2, iOS 5