Mix 5.1 Audio Down To Stereo With ffmpeg

This can help if you only listen through stereo speakers and the dialog is mized for a 5.1 or 7.1 or whatever setup.

I haven't tried this on, but keeping it here for reference so I don't lose it when I'm ready to try it

Via:

https://hachyderm.io/deck/@johnnydecimal/111622141507326664