My screen brightness used to dim after a few seconds to preserve battery. This is default in Ubuntu 12.04. However when watching video it should not dim.
This works correctly when I watch videos using native applications like VLC. With in-browser video, however, the screen is not prevented from dimming.
This is very annoying as you have to move your cursor every 10 seconds or so.
I used to use Mac OSX where I had the same dimming settings and Flash videos were taken into account correctly.
Anyone an idea how you can make YouTube prevent your screen from dimming?