scottopell

1. Install mkvtoolsnix.
2. brew install --with-qt5 mkvtoolnix
3. Use mkvinfo to get the audio track IDs that you want.
4. mkvinfo *.mkv
5. Note that the audio track IDs are not the track numbers. Check the man page of mkvmerge or mkvinfo for more details.
6. Use mkvmerge to create a copy of the mkv with ONLY the desired tracks using --audio-tracks.
7. mkvmerge -o out.mkv -a 2 orig.mkv