Leah

MKV has no sound on Mac: why it happens and how to fix it

An MKV file plays without sound on a Mac when the app playing it can’t decode the file’s audio format. The picture and the sound are separate tracks inside an MKV file, so a player can show the video while skipping audio it doesn’t understand.

The usual cause: the audio format

Movies and TV episodes in MKV files often carry surround sound in formats that macOS’s built-in player doesn’t decode inside MKV:

• Dolby TrueHD, the lossless surround format from Blu-ray discs, often with Dolby Atmos.
• DTS, including the DTS core of DTS-HD Master Audio and DTS:X tracks.
• Dolby Digital (AC-3) and Dolby Digital Plus (E-AC-3).

QuickTime Player doesn’t open MKV files on its own. Other players may open the file but play it silently, or play only some of these formats.

How to check the audio format

A player that shows track details, or a tool such as MediaInfo, shows the audio format of each track. Look for the audio track’s format: TrueHD, DTS, AC-3, E-AC-3, AAC, FLAC, Opus or Vorbis.

How to fix it

1. Use a player that decodes the format. Leah plays Dolby TrueHD in up to 7.1 channels exactly as recorded, DTS in up to 5.1, and Dolby Digital, Dolby Digital Plus, AAC, FLAC, Opus, MP3 and Apple Lossless. See Formats Leah plays.
2. Check the audio track. Some files have more than one audio track, such as a main track and a commentary. A DTS Express commentary track, for example, has no DTS core and plays silently in Leah. See DTS audio on Mac.
3. Check the output. Make sure your Mac’s volume is up, the app isn’t muted, and sound is going to the speakers or headphones you expect in System Settings > Sound.

Formats that won’t play in Leah

Vorbis audio, used in some MKV and WebM files, isn’t supported. Leah plays such a video without sound. DTS Express commentary tracks don’t play either.

For video and subtitles too, see How to play MKV files on Mac.

Get Leah

Leah is a video player for Macs with Apple silicon and macOS 15 or later, on the Mac App Store.