www.makemkv.com

This is not universal... but... A lot of Anime has multiple English tracks, and even multiple Japanese. The extra tracks are (usually) commentary. On a series that was mastered with "one large play-all track" that contains all the episodes (even if MakeMKV finds the individual episodes), ...

A show (Death Note) I've been ripping keeps episodes with commentary as separate files. I've been using mkvmerge to take just the one audio track containing the commentary and adding it to the file with everything else. I've noticed though that the commentary files contain two english subtitle track...