I've seen people push for this on the web and social media in the past, but they never push hard enough. So I'm going to try one more time...
Consider the way your TV is turned or the way a movie screen is oriented. It's longer side to side than it is tall, isn't it?
So then why in the name of all that's holy wouldn't you hold your smartphone's video camera in a way that would record video to fit in that space??
For the love of God, people, defy your inherent holding tendencies and TURN YOUR PHONE SIDEWAYS (landscape orientation) FOR VIDEO CAPTURE!!
[image courtesy of PemBlog]
That is all.