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No sound from your MKV in Final Cut or QuickTime

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The picture is there. The waveform is flat. QuickTime plays the file in silence, or Final Cut imports it with an audio track that exists and produces nothing. Nothing is obviously broken, which is the frustrating part. The file plays fine in VLC or IINA, so it is clearly not corrupt.

Two different problems produce this symptom, and they have different fixes.

Problem one: Apple cannot decode the format

Blu-ray and DVD backups routinely carry DTS, DTS-HD Master Audio, or Dolby TrueHD. VLC and IINA play them because they bundle their own decoders. Apple’s media stack does not include a decoder for any of them. That stack sits underneath QuickTime, Final Cut Pro, Compressor, and every other app built on AVFoundation.

So the track is present, correctly described, and completely silent. Nothing in the file is wrong. macOS simply has no way to turn it into sound.

The fix is to convert that one track to something Apple does decode. The right target is 24-bit PCM: DTS-HD Master Audio and TrueHD are lossless formats, so decoding them to PCM keeps every sample. You are unpacking the audio, not degrading it. The file gets larger, because PCM is uncompressed, and the sound is identical.

What you must not do is re-encode the video to get there. The audio is the only thing that needs to change.

Problem two: the audio decodes, but comes out of the wrong speakers

This one is worse, because it does not look like a failure. The track plays. Dialogue is just quiet, or coming from the left, or the surrounds are dead.

A 5.1 track is six channels in a specific order, and the file has to say which channel is which. MOV and MP4 record that as a named channel layout. A tool that writes six channels without naming the layout leaves Apple to guess, and the guess is frequently wrong: Center lands where Left Surround should be, and your dialogue walks into the wrong speaker.

You often will not catch this on a stereo laptop. You catch it in the mix room, which is the expensive place to catch it.

Why “just remux it” is not enough on its own

A plain container swap copies the audio stream across as it is. That covers ffmpeg -c copy and any tool that only rewraps. If Apple could not decode DTS-HD before, it still cannot. And a stream copy that does write PCM without a named layout produces exactly the wrong-speaker problem above.

What you need is narrower and more specific: convert only the tracks Apple cannot read, to PCM, with the channel layout named correctly, and leave everything else alone.

What ClipReady does about it

ClipReady looks at every audio track and gives it one of three verdicts before anything runs:

  • Copied. AAC, AC-3 (Dolby Digital) and E-AC-3 (Dolby Digital Plus) are formats Apple already plays, so they cross into the new file untouched.
  • Converted. DTS-HD Master Audio, TrueHD, DTS and multichannel ALAC are decoded to 24-bit PCM at full channel count. For the lossless formats, nothing is discarded.
  • Stays behind. A few formats have no decoder in the bundled runtime at all, and ClipReady says so and leaves the track in your original file instead of guessing at it.

The channel layout is written as a named CoreAudio tag and checked against Apple’s own decoder, the same one Final Cut and QuickTime use, rather than trusted from the source file’s tags. Center stays Center.

And because it is a remux, the encoded video is carried across without ever being decoded. Fixing your audio does not cost you a generation of picture.

If you would rather keep the file small

Uncompressed 24-bit PCM makes a big file. ClipReady offers a compact option, E-AC-3 or AAC, as an explicit, labeled choice. It will never quietly pick the lossy path for you and call it lossless.