This seems to be the conclusion I read from Arstechnica tests and some comments: http://wccftech.com/ios-9-battery-tests/ I noticed a decrease here, too, I have an iPAD 4 that had the iOS 7, and only when I updated to iOS 9 I noticed it is somehow wasting more battery. I usually let the brightness in 90%, and I am not changing everytime I want to watch a video, I always let this way, and using iOS 7 it was not wasting so fast. It seems Arstechnica tests showed there was no decrease in other devices, compared to iOS 8.4.1. Even iPAD 2 improved a little with the new iOS. Only iPAD 4 (and I'll assume 3, too) is having this issue. Was this deliberate or it depends on some factors, such as the age of the equipment you have? Mine was purchased when they released, and I've been using on a daily basis, but charging everyday, too. And I am always using almost completely the battery everyday, too. I might be wrong about the iOS and battery, yet I'll need to do more tests. What I noticed was that using the app Documents by Readdle to download PDFs and sending the contents (use the "copy" option) to Foxit Mobile PDF (another app) is capable of wasting as much battery as the VLC player, over time.