If anyone else decides to give this a try on video files with multiple audio tracks, there doesn't seem to be an easy way to tell it to select a certain track.

I got it working by manually adding `-map 0:2` (`2` being the trackid I'm interested in) when calling ffmpeg.

You'll have to make that edit in both `videogrep/transcribe.py` as well as `moviepy/audio/io/readers.py`.

And I'm not sure how easy adding real support for that would be, considering that moviepy doesn't currently have a way to support it (https://github.com/Zulko/moviepy/issues/1654)