How to remove commentary tracks and unwanted languages from an MKV on a Mac

A full remux is faithful to the disc, and that means it has everything on the disc. A typical 4K film might carry a lossless main track, two or three dubs, a couple of commentaries and a dozen subtitle languages. That’s great for an archive and less great when your player opens the film in the wrong language, or starts on the director’s commentary.

What a tidy file looks like

• Only the languages you watch in. Audio and subtitles in other languages are left out.
• No commentary, unless you want it.
• The right default audio, so the film starts in the language you expect.
• Forced subtitles marked as forced. A forced track only covers the lines you’re not meant to understand, like a few lines of another language or a sign on screen. Players can show it automatically, but only if it’s flagged.
• Every track labelled. Tracks tagged “undetermined” defeat a player’s language preferences.

None of this needs anything re-encoded. Leaving out a track, or changing its flags and labels, is just a remux: everything you keep is copied exactly.

The manual way

MKVToolNix is excellent and free. Open the file, untick the tracks you don’t want, set the language, default and forced flags on the rest, and start multiplexing. It’s quick for one film. For a whole library, it’s the same set of clicks, file after file, and it’s easy to miss one.

With Remux Doctor

Remux Doctor treats tidy tracks as part of your target, so it can check and fix a whole library at once.

1. Say what you want. In your target, choose the audio and subtitle languages to keep, whether to leave out commentary, and the default audio language.
2. See which files differ. Every file with extra languages, commentary or the wrong default is flagged, with the change it needs spelled out.
3. Fix, one file at a time or with Fix All.

A few details worth knowing:

• Commentary is found by name. Tracks named as commentary, such as “Director’s Commentary”, are left out. Check any file where the commentary isn’t labelled.
• It won’t leave a film silent. If a film has no audio in the languages you keep, it keeps its audio rather than removing every track.
• Untagged tracks can be labelled, so they stop showing up as “undetermined”.
• On a single file you can also choose the default and forced subtitles, rename tracks and set the file’s title.
• The DTS core. A DTS-HD Master Audio track has a lossy DTS core built in. Remux Doctor can add that core as its own track alongside the original, for gear that only decodes plain DTS. It’s copied out, not re-encoded.

Tidying tracks works on MKV files for now. As with every fix, the result is a new file, checked before it’s kept, and your original stays as it is.

Keep the archive, tidy the copy

If you like having every track somewhere, keep the original remux on an archive drive and point your player at the tidied copies. Remux Doctor can write new files to a folder you choose, so the two never get mixed up.

Examining and checking your library is free, and you can fix your first three files free to see the result. After that, every fix is a one-time unlock with Family Sharing. Remux Doctor is coming soon for Macs with Apple silicon running macOS 15 or later.