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How to convert a DTS audio file to MP3 on a Mac

· 6 min read

A .dts file is surround sound audio pulled from a disc or a video, and nothing built into macOS plays it. Converting it to MP3 gives you a file that plays anywhere, but the conversion folds the surround mix into stereo and discards some detail, so keep the DTS file if the original mix matters to you.

What a DTS file actually is

DTS is a surround sound codec used on DVDs, Blu-ray discs and some downloaded video. A standalone .dts file usually appears when the audio track has been extracted from a movie or concert disc and saved on its own. It may carry five or more channels: left, right, center, rear speakers and a low-frequency channel.

That is useful in a home theater and awkward on a Mac. QuickTime Player does not read it, Music will not import it, and Quick Look in Finder shows a plain icon. Nothing is wrong with the file. The Mac simply has no decoder for it, which is the same situation as what an MKA file is and many other disc-era formats.

What you lose going to MP3

Two things change at once, and it is worth knowing both.

  • Channels. MP3 is built for stereo. A five-channel DTS mix must be mixed down to two channels. Dialogue and music usually survive well, but the sense of sound coming from behind you is gone.
  • Detail. MP3 is lossy. It discards sound the encoder judges you are unlikely to hear. At a reasonable bitrate this is fine for casual listening, and it cannot be undone.

If you want to preserve the surround mix, MP3 is the wrong target. AC3 and a few others hold more channels, but they do not play on a Mac either. For a copy you can actually listen to on a phone, in a car or in Music, stereo MP3 is the practical choice. Why converted audio sounds worse than the original explains what to expect.

Convert it with Manatee

Manatee accepts DTS audio as an input and can write MP3. It bundles its own ffmpeg engine, so nothing needs installing, and the whole job runs on your Mac with no upload.

  1. Open Manatee and choose Convert.
  2. Drop the .dts file, or several, into the window or onto the menu bar icon. You can also right-click a file in Finder and use Services, then Fix with Manatee.
  3. Choose MP3 as the target.
  4. The MP3 is written beside the original. The DTS file is never changed.

Manatee is free for 24 hours with every feature, then $9 once. Once the MP3 exists, double-click it to play it in QuickTime Player, or drag it into Music to add it to your library.

Converting with ffmpeg in Terminal

If you already use ffmpeg, this converts the audio and mixes it down to two channels at a good quality setting:

ffmpeg -i track.dts -ac 2 -q:a 2 track.mp3

The -ac 2 option does the stereo mixdown, and -q:a 2 selects a high-quality variable bitrate. Lower numbers mean better quality and bigger files, so -q:a 0 is the best and -q:a 6 is noticeably more compressed.

If the mixdown sounds quiet, the cause is common: five channels folded into two lowers the overall level. You can raise it with the -af volume=1.5 option, but listen for distortion.

When the DTS audio came from a video

Often the real situation is a movie file whose sound is DTS, and you want the audio as MP3. You do not need to extract the DTS first. Drop the video itself into Manatee and convert it to MP3, which pulls out the sound and mixes it for stereo in one step. How to convert MP4 to MP3 covers the same idea for ordinary video files.

If the video has several audio tracks, such as different languages, play the result and check you got the one you wanted before deleting anything.

Checking the result

  1. Play the start and end of the MP3. If the file cuts off early, the original may have been cut short; an MP3 that shows the wrong length explains how that looks.
  2. Check the volume against other music in your library. A surround mixdown is often quieter.
  3. Keep the DTS file until you are happy with the result, especially if it came from a disc you no longer have.

Questions

Can QuickTime Player play a DTS file? No. It cannot decode DTS, so the file will not open there. Converting to MP3 or another format Apple supports is the way around it.

Will I keep the surround sound? Not in an MP3. It is a stereo format, so the channels are mixed down to two. Keep the original DTS file if the surround mix matters.

Is the original file changed? No. Manatee writes a new MP3 next to the DTS file and leaves the original as it was.