Earlier quoted context omitted.
But how many hours of video playback?
My iPhone today last for less than a day while I dont watch any video on it, In fact, i barely use it currently, and it still drains batteries in no time. And yes, I disabled most background services and location services and run screen on low brightness - all the popular hacks to reduce battery usage.
The drop down menu doesn't actually disable bluetooth so that alone won't work.