LG G5 TV with Apple TV4K and Sonos Arc, only Dolby Atmos and PCM, missing Dolby Digital

The Apple TV decodes everything (besides Atmos) into (Multichannel-) PCM, so that’s normal and there’s no real solution. You could set the audio output to Dolby Digital though, but then you won’t have Atmos.

Is there any option to improve PCM playback on Sonos Arc, to make it sound more like DD?
Tbh PCM sound extremely flat in comparison to DD :(

No, not that I’m aware, but to be fair I also don’t really notice any difference between Dolby and PCM (using an Apple TV myself) only that you might have to raise the volume a bit to have the same levels as Dolby.

Maybe, it’s only volume I need to test it a little bit longer.

​@kXender 

So you’re not even getting 5.1 when content is non-Atmos on streaming services?

It depends on app. Netflix is giving Multichannel 5.1 PCM, youtube Stereo PCM.

YouTube is not a good test.  99.9% of YouTube content on a free account is downgraded to 2.0 stereo.  Even if it is uploaded as DD 5.1, it is stored in stereo, and you cannot trust anything advertised as 5.1 or Atmos

On my Apple TV, I just watched Ballard on Prime and Ripley on Netflix - in both instances, Sonos Arc showed sound as Dolby Digital 5.1. So I’m not getting ‘downscale’ 5.1 Multichannel PCM like you are. (I’m on the tier below premium, so I don’t get Atmos on Netflix, only Apple TV+, FYI). 

On your Apple TV, under Video and Audio, does your Audio Format say (before selecting it) “Auto, Atmos Available” and then when you select it, say Change Format “Off” and Dolby Atmos “On”? 

Further down on Video and Audio, does Audio Mode say “Auto”?

(I'm trying to ascertain why you’re getting 5.1 PCM and not Dolby Digital 5.1…  Let me know content where you’re seeing 5.1 Multichannel PCM and I’ll compare.)

I have a Samsung Q90T, not an LG so can’t compare there…

1. I have YT Premium
2. In Apple TV I have Atmos Available and Change Format Off
3. Audio Mode “Auto” I assume set in TV? I have it set to Auto.
4. First answer in the thread from Outburst: 

   The Apple TV decodes everything (besides Atmos) into (Multichannel-) PCM, so that’s normal and there’s no real solution. You could set the audio output to Dolby Digital though, but then you won’t have Atmos.

   I think this is true, confirmed by searching google nad ChatGPT :)
   
   it is unfortunate, but it is how it is :(

From what I’ve read, passthrough will be available on TvOS 26 so AppleTV will no longer process always the sound.

https://appleinsider.com/articles/25/06/10/passthrough-audio-is-finally-on-the-way-to-apple-tv-iphone-and-more/amp/

Sounds awesome if it’s True.

I’m not disputing it - but just I wonder (for non-Atmos content) why it displays ‘Dolby Digital 5.1’ on my Sonos app’s Now Playing screen when using Apple TV to Samsung TV to Arc, whereas you’re only seeing ‘5.1 Multichannel PCM’ when using Apple TV to LG TV to Arc...

Maybe your TV is converting it back to Dolby Digital or you have “Change Format” enabled in the Apple TV settings? It’s very strange, I only get PCM or Atmos with my Apple TV and that’s how the Apple TV operates for years now.

As mentioned Apple might add Passthrough but I think that’s nothing more than a rumor right now.

No, Change Format is off... I’m not forcing Dolby Digital 5.1, and also get Dolby Atmos on Apple TV+.

I do get PCM from live broadcasts on BBC iPlayer and ITVX on Apple TV, but that’s to be expected. But for the vast majority of streamed content on Disney, Prime, and Netflix, I get the app displaying ‘Dolby Digital 5.1’. (The TV is on Passthrough too, so it shouldn’t be doing any converting...)

Do you have an example for Disney? I have a subscription there currently so I could check that out.

Hundreds.  Any newer (since 2010) Marvel movie (Avengers: Infinity War, Avengers: Endgame).  Any Star Wars series (Andor, The Mandalorian).  

​@Outburst 

Yes, what ​@jgatie said!

Here’s a screen grab during Return of the Jedi (not Premium tier - if I did, it would be saying Atmos):

I tested with Captain America Brave New World now and I get Multichannel PCM as I would have expected. Really odd that you get DD5.1 here.