zoom: Great Zoom Video Background from iPhone Videos

There are a couple of steps to get this to work right because there are a couple of problems to get a Zoom background:

Taking a video with an iPhone is handheld and if you take a nice shot it wanders
The video has to work while looping, so you don’t want to just cut something off, so for instance if you have a canoe going through, make sure it completely exits the frame and enters the frame so you don’t get a jump
The default format of the iPhone is HEIC (x.265) which Zoom doesn’t know how to deal with
The default most of the time is 4K while Zoom only handles 1080p
The file extension must be a .mov file container and it doesn’t know extensions like .m4v

So the fix is a little painful but it does work:

Start-up Final Cut Pro and choose Import to get the videos from your phone
Create an Event that is 4K HDR as that’s the default format
Then create a project for video and import a single clip
Now in the clip properties, go to the right and scroll down to stabilization and turn it on. It will take some time for it to analyze motion.
If Final Cut Pro determines it can be totally stabilized then in Automatic or Inertia mode the “Tripod Mode” will be checkable. If it isn’t then you probably can’t use his as your zoom background.
If you didn’t correctly have all moving things either stay in frame, then crop it so it works so that the objects either end up in the same position that they started or they exit and enter smoothly so you don’t get a “jump frame”
If the video isn’t quite horizontal, then you can choose the “transform” tool in the lower left of the preview window. You will get two handles, the one on the right you can rotate to make it smooth. To make it easier, in the preview window at the upper right, there is a view menu, and select “view horizon” to make sure you have this right. In preview it will show the tilted clip, but in play, it will crop it out nicely.
Now choose File > Send to Compressor
Pick as the format for the Compressor, the preset Apple Devices HD, you will get a warning about HDR input but that doesn’t seem to matter
This will produce a file in .m4v format, so rename that to .mov
Start Zoom and import it and it should work!