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Apple Broke Dolby Digital 5.1 Output on Apple TV 4K

Not sure why nobody else is mentioning this, but figured I'd post to help others. One of these last few tvOS updates has completely broken Dolby Digital output (on Apple TV 4K, it seems).


I have a 2nd gen 4K model that had been fine until a recent update. I change the audio output in Settings to force Dolby Digital 5.1 for my speakers (Logitech Z906), but this suddenly no longer works! My speakers do not light the proper "Decode" light to indicate a true 5.1 signal, and the voices clearly come from left and right channels instead of just the center.


This was easy to confirm. I purchased a brand new 3rd gen Apple TV 4K (128GB) and it shipped with tvOS 17.1. I configured the audio output to force DD 5.1 and tested a movie... and everything worked perfectly. The "Decode" light indicated a 5.1 signal and voices, etc, clearly only came through the center channel. Then I upgraded to tvOS 17.4 and immediately tested the same movie, and it's broken! Nothing else changed.


Strangely enough, I have an old 1080p Apple TV running tvOS 17.4 (latest) and it still outputs Dolby Digital just fine.


I have provided this information to AppleCare as well as Apple.com/feedback. Kind of a ridiculous bug to go unpatched still. Hopefully someone will notice while we all sit here with broken audio.

Posted on May 7, 2024 10:30 AM

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Posted on Sep 16, 2024 10:59 PM

updated to TvOS 18 and 5.1 is broken. Apple TV connected to TV Samsung KS8000. HDMI ARC to Yamaha receiver. Only detects stereo. Please fix asap.

280 replies

Sep 24, 2024 1:52 PM in response to llee

Anyway, let me explain the situation as I see it. If your audio system is automatically detected by your Apple TV as a system that can use multichannel audio, then fine, you're one of the lucky ones. However, Apple engineers created a back door for audio systems that can use multichannel audio, but which are not recognized as such by the Apple TV. For the people who need it, it's the only way to receive multichannel audio. A simplified summary of the back door is the "Change Format" option. I'm convinced that it's this back door, the "Change Format" option, that is broken.

Sep 28, 2024 11:56 AM in response to llee

Agreed. I have two Apple TVs and this update broke them both. They work perfectly fine except the crippling the update has done and no reason they should be replaced. I'm not purchasing another one because of that. I'll switch to something with more freedom. Updates breaking important features is not something I will look passed. I really hope Apple makes good and fixes this soon but so far, it seems they won't even acknowledge it.

Oct 1, 2024 8:22 AM in response to Payton Garner

Same thing happened to me after the tvOS 18 update on my Apple TV HD. I change the audio output in Settings to force Dolby Digital 5.1 for my speakers (Logitech Z906). I pass my audio from the tv to the speakers with a TOSLINK optical cable.


A fix that worked for me. I temporarily switched my audio output to my HomePod mini from the Control Center and then switched back to TV speakers. Now I am getting a 5.1 signal. It works with AirPods too. As long as you switch the audio output to something else and then back to TV, it seems to correct itself.


Definitely a bug that Apple needs to fix.

Oct 3, 2024 9:34 PM in response to Payton Garner

I have an Apple TV HD and can’t find the solution that people are saying is working for them.


Apple TV > Samsung Smart TV > optical > Sonos.


PlayStation, Sky Stream, smart tv apps all output Dolby digital. YouTube surround test works, otherwise the Apple TV reverts to PCM stereo.


This was working fine, but now can’t get it to work. I’ve tried everything I can.

Oct 9, 2024 2:30 AM in response to Payton Garner

I was quite fortunate to have 2 x individual 4K Apple TV pucks. One of them updated to TVOS 18 resulting in a loss of DD5.1 via my Yamaha AVR. The other remained on TVOS 17.6.1 and still supported DD5.1, so I was able to switch the pucks over.


note to self: Disable auto updates. Only update one and review for bugs.


The b version has fixed it the issue for me, but still keeping the other on 17.6.1 until the official update is pushed out for me to review.


Thank you to those of you that started of the thread, and reported to A HQ.

Oct 28, 2024 8:46 AM in response to Payton Garner

So I just updated to the latest tvos 18.1 public released version. And as I already noticed on the b versions, the problem has not been fixed for me. Switching to dolby 5.1 does not give me surround sound. The light which indicates that it is receiving a dolby digital 5.1 signal on my logitech z906 doesn't light up. This is very disappointing, as I beginning to lose hope if it will ever be fixed.

Sep 17, 2024 7:26 AM in response to Paul Brook

Unfortunately, I’m beginning to think this “bug” is more of an architectural change to how Apple TV 4K handles Dolby signals overall, and our specific configurations and equipment just happen to be victims of this codec adjustment. As it has been an issue so long now, I don’t have lots of hope this will be addressed. The best thing we can do is give feedback here…


Feedback - Apple TV - Apple


Since audio is half the experience, this is difficult to accept. After all, if all of our Apple TVs started outputting 1080p instead of 4K, I’d imagine that would be fixed by now.


Until we get eyes on this from engineers, just continue to send feedback and hope it gets noticed. At least this thread lets people know they’re not alone.

Oct 4, 2024 11:49 AM in response to llee

Interesting. Sounds plausible to me. Here's that documentation on Apple's Dev website for the technical crowd:


AudioConverterFillComplexBuffer(_:_:_:_:_:_:) | Apple Developer Documentation


Also might explain why this works for some apps and not others. If that particular app is using another method or API to convert audio, it may not be affected.

Apple Broke Dolby Digital 5.1 Output on Apple TV 4K

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