mime file type different in nautilus and file command

Question

I have various mp4 files, and nautilus correctly detects them as video/mp4.

However, the file command says:

$ file -i *.mp4

name20.37.00.mp4: video/mp4; charset=binary
name20.46.22.mp4: audio/mp4; charset=binary
name20.56.40.mp4: audio/mp4; charset=binary
name20.57.28.mp4: audio/mp4; charset=binary
name21.08.09.mp4: audio/mp4; charset=binary
name21.18.26.mp4: audio/mp4; charset=binary
name21.30.16.mp4: audio/mp4; charset=binary
name21.41.28.mp4: audio/mp4; charset=binary

why do I get this?

I'm on ubuntu bionic, but I get the same result with the same files in debian buster.