Manatee

What an MKA file is, and how to play or convert it on a Mac

· 6 min read

An MKA file is a Matroska audio file: the sound-only sibling of the MKV video format. Nothing on a Mac opens it out of the box, because QuickTime Player, Music and Quick Look do not read Matroska at all. The practical fix is to convert it once into a format the Mac understands: M4A or MP3 for listening, or FLAC to keep every detail.

What is inside an MKA

Matroska is a container: a box that holds audio (and, in an MKV, video), along with extras such as chapter markers, tags, cover art and more than one track. The .mka extension says “this box holds only audio”. It does not say which audio.

Inside you might find any of these:

  • AAC or MP3, the same compressed audio your music library uses.
  • Opus or Vorbis, compressed formats common in files that came from the web.
  • FLAC or plain PCM, lossless audio with nothing thrown away.
  • AC-3 or DTS, surround sound tracks lifted out of a film.

The difference matters because it decides which format you should convert to. Container vs codec explains why two files with the same extension can behave so differently.

MKA files usually come from one of three places: an audio track someone pulled out of an MKV movie, a concert or radio recording made with capture software, or an album or audiobook kept as one long file with chapter markers.

Why the Mac will not play it

macOS builds its media support around the MPEG-4 family (MP4, M4A, MOV) plus older formats such as MP3, WAV and AIFF. Matroska is not on the list. So an MKA shows a generic icon in Finder, pressing Space gives you no preview, and double-clicking it either does nothing useful or asks which app to use.

Renaming does not help. Changing .mka to .m4a or .mp3 leaves the Matroska box around the audio, and the Mac still cannot open the box. Even when the audio inside is AAC or MP3, it has to be taken out and put into a container the Mac reads.

Working out what kind of audio you have

No tool that ships with macOS can look inside Matroska. In Terminal, file followed by the file’s path will confirm it is “Matroska data”, and stop there. The file size gives a better hint, if you know roughly how long the recording is. Divide the size in megabytes by the length in minutes:

  • Under about 2.5 MB per minute: compressed stereo audio such as AAC, MP3, Opus or Vorbis.
  • Roughly 5 to 11 MB per minute: most likely lossless stereo, FLAC or PCM.

Surround tracks from films break the rule, because they can be both compressed and large. If the file came out of a movie, assume it is surround and read the section on what may not survive the trip below.

Converting MKA on a Mac

With nothing built in that reads Matroska, you need a converter that brings its own decoder. Manatee bundles one, and MKA is among the formats its Convert mode accepts:

  1. Open Manatee and choose Convert, or drag the MKA files onto its menu bar icon.
  2. Drop in one file or a batch.
  3. Pick a target: - M4A to play it in Music, on an iPhone, or in anything Apple makes. - MP3 to play it on almost anything, including older car stereos and other people’s devices. - FLAC if the audio inside is lossless and you want to keep it that way. - WAV if you are going to edit it, for example in GarageBand.
  4. Each converted file is written next to the original, which is left untouched.

Everything runs on your Mac with no upload and no account. Manatee is free for 24 hours with every feature, then $9 once.

If the audio inside is already compressed, converting it to M4A or MP3 compresses it a second time. At a sensible bitrate that is hard to hear in everyday listening. Converting compressed audio to FLAC or WAV, on the other hand, does not restore anything; it only makes the file bigger. Lossless vs lossy explains the trade-off.

What may not survive the trip

Matroska can hold more than an MP3 or M4A can, so check the result before you delete the original:

  • More than one track. An MKA taken from a film can hold several languages or a commentary. A conversion produces a single track, so listen to confirm you got the one you wanted.
  • Chapters. Albums, audiobooks and concert recordings in MKA often carry chapter markers. MP3 has no widely supported place for them, so expect to lose them there.
  • Surround sound. MP3 holds two channels at most, so a 5.1 track has to be folded down to stereo. Converting AC-3 surround audio covers the choices when you want to keep the channels.

Keep the MKA until you have played the converted file through. It costs some disk space, and it is the only copy with everything in it.

If you still have the MKV it came from

If the MKA was pulled out of a video you still have, you can skip it and convert the MKV straight to an audio format. The steps are the same: drop the MKV into Manatee’s Convert mode and pick MP3 or M4A. How to convert MP4 to MP3 walks through taking the audio out of a video, and MKV file won’t open on Mac covers the video side.

Questions

Is MKA a lossless format? Not in itself. MKA is only the container, so the file is lossless if the audio inside is FLAC or PCM, and lossy if it is AAC, MP3, Opus, Vorbis or AC-3. The size check above is the quickest way to guess.

Can the Music app import an MKA? No. Convert it to M4A or MP3 first, then drag the result into Music. M4A is the better fit if the file will end up on an iPhone.

What is the difference between MKA, MKV and WEBM? MKV is the same Matroska container with video in it. WEBM is a restricted version of Matroska designed for the web, usually with Opus audio. What is a WEBM file covers that format, and OGG and Opus audio covers the web audio formats you may find inside an MKA.