Still trying to get this MP4 to play...

[M A V I C]

There has to be another way. It used to work. It works on two other machines.

The other challenge is transcoding creates a lot larger files than the original. This is a shared family laptop, and there's not enough storage to deal with transcoding.

I managed to get iMovie to update. The Mojave version has a feature to check media compatibility. It says the media is supported.