Thor, or should that be Zeus?

[AndyGuid]

. . . . I hadn't realised myself why some videos were like that until I happened to trip over that explanation

Thanks for that Andrew, I hadn't realised this until I just read your post!
I thought videos displayed in three vertical stripes like that were simply some new technological fad intended to irritate some of us old farts! Lol
Maybe people shooting vertical videos are often unaware of this, I certainly would have been.
Let's hope the manufacturers improve their default settings to mostly phase out this mode of recording.