In the frame
If you shoot video on a phone, what’s in the frame depends how you hold it. Because it is a phone, the temptation is to hold it upright a.k.a. portrait orientation to shoot video. That’s all good but it can limit your viewing options. Social media platforms accommodate this orientation by hiding the redundant third of the screen on either side of your vision from view.
However, if you want it to be seen on a computer monitor, TV or on YouTube or vimeo make the most of the screen real estate on offer by turning the phone on its side and filming in landscape orientation. The advantages of this aspect are no black bars on either side of your footage and an entire screen to make use of into the bargain. What’s to lose?