I often stream videos in bed before falling asleep. Since I have the lights turned off, I manually turn down the phone's brightness to the lowest setting. And time to time, I notice the phone dims a little for a second (I don't know how the phone can dim even more since I have the brightness setting to the lowest possible...), and then comes back to set brightness. This is annoying at times since sometimes images on the the videos become so dark I can't even recognize what's being displayed. I can't say how often this happens, but I would say it happens 2-4 times during 30-minute duration. It happens on all streaming apps I use - YouTube, Mubi and Shomi. What I am not sure about is whether this happens on other apps (not just video streaming), whether this is iOS or hardware, whether these specific apps are causing this, or whether this happens only when videos are being played. Anyone else experience this? I have a 5S with 8.4.1.