Whenever I watch a video on my Android tablet (in landscape mode), from any source (e.g. web via Chrome, iPlayer, 4OD, mp4), there are black bars at the top and bottom of the screen. When watching the same video on my laptop, which has the same resolution and therefore aspect ratio, the bars are not there. Android seems to squashing the video vertically making people look shorter and fatter. Why, and how do I stop it from doing this?