I've tried using ffmpeg, but it seems to keep all the metadata I'm actively looking to remove.
I'm looking to remove ALL metadata, including length, bitrate, etc. Before you say this isn't possible, yes it is, and I have multiple files that have what I'm looking to do. The files without metadata are still fully playable.
Example of what I want to do:

I've also tried exiftool but it doesn't work with WebMs.
I tried the solution here and it didn't work. The output of ffmpeg on one of the WEBMs without metadata is:

ffmpeg -i nometadata.webm– Gyan Jan 24 '19 at 04:38I tried the solution on superuser here: https://superuser.com/questions/441361/strip-metadata-from-all-formats-with-ffmpeg
– John Texas Jan 24 '19 at 05:29