No, I was running on normal untrusted video files. The standard ffmpeg command line would happily attempt to parse those with the LucasArts Smush codec even though I'd never heard of it before.

See the POC in the report by google, the command they run is just `./ffmpeg -i crash.anim -f null /dev/null -loglevel repeat+trace -threads 1` and the only relevant part of that for being vulnerable is that crash.anim is untrusted.

Edit: And to be clear, it doesn't care about the extension. You can name it kittens.mp4 instead of crash.anim and the vulnerability works the same way.