When people create videos using their cell phones, they usually do it in portrait mode. Not being someone who whips out a camera and records things, I am not sure why the portrait mode is the one that people prefer. Is it something to do with the ease of holding the phone? But whatever the reason, the net result is curiously dissatisfying to watch, apart from the black bands that appear on each side when you play it back on YouTube or a video player.
Rob Beschizza digs up a paper from NASA that suggests that there may be a physical reason for our preference for landscape mode videos and that is that the field of vision for human eyes correspond roughly to an aspect ratio of 16:10, close to the widescreen format in films.
But while landscape is easier on the eye for watching vides, why is it different for reading? A random check of the books on my desk reveals that they are close to the portrait mode aspect ratio of about 10:15.
Is it that the ways our eyes scan when we sequentially read text is different from the way we watch videos?