Apple TV 4k 2022 and Multichannel PCM - audio dropout every 40 seconds

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12 points

Apple TV 4k 2022 and Multichannel PCM - audio dropout every 40 seconds

Hi guys,

I have an issue with my new Apple TV 4k 2022 (64GB). I'm using the default audio setting (Change Format: Off, Dolby Atmos: On). With this settings, audio is being sent in PCM (sources with 2-channel stereo format) or Multichannel PCM (everything above). Now the problem is that when Multichannel PCM is being used (and this is the case for pretty much all content, be it Dolby Digital 5.1 (Plus) or Atmos), an audio dropout of approx. 1 second occurs every 40 seconds. This is clearly reproducable.

The issue does not occur if I either playback something that has only 2 channels (stereo), or if I change the Audio setting in Apple TV to "Change Format: On" -> "Dolby Digital 5.1". This causes the box to output a bitstream rather than a PCM signal.

The box is connected to an LG C2 OLED. Audio device is a Sonos Beam Gen2 in a 5.1 setup.

It should be noted that the new Apple TV 4K 2022 replaced an Apple TV 4K 2021. Everything except the box itself remained the same, including all cables. So the new Apple TV is really the only variant. If I put back the 2021 model, the issue does not occur, so to me this really looks like a bug in the new Apple TV.

PS: I can clearly reproduce the issue with Netflix and Amazon Prime Video. With both apps, the audio output of most of the content is Multichannel PCM (given Apple TV audio setting is at the default values). Interestingly, it does not occur in Apple TV+. All the content that I tested is being displayed as "Dolby Atmos" rather than "Multichannel PCM 5.1" in the Sonos app. Not sure whether this means that Apple TV+ audio is being sent as bitstream, or if the Sonos app can differentiate MPCM signals with and without Atmos. So you won't see the issue with most (or all?) content on Apple TV+, but with pretty much everything in Netflix and Amazon Prime Video.

Apple TV 4K

Posted on Nov 10, 2022 2:13 PM

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Answer 1

Dec 13, 2022 8:50 PM in response to Kay L.

Hey Kay! Very interesting post. I dl have the exact issue as you except for the dropouts. I have a sony a80j and spent several minutes tweaking settings thinking there was a handshake issue between apple tv and sony tv. Interestingly, i fixed it by switching the eARC function from Auto, to off... the exact opposite of how it should work. Once i did that.... everything started to come out as Dolby 2.0, 5.1, and atmos just as it's intended format.

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Answer 2

Kay L. Author

Level 1

12 points

Nov 10, 2022 2:51 PM in response to Kay L.

PPS: Another interesting finding: The mentioned 40 seconds are NOT related to the playback time of the media, but instead to the realtime! So it would seem that the box does something every 40 seconds that causes the dropout.

I noticed this because during my first test, the dropout occured in the following time pattern:

11:40:00

11:40:40

11:41:20

11:42:00

11:42:40

...

now when I retested with some other media, the pattern in relation to realtime is the same:

11:47:00

11:47:40

11:48:20

11:49:00

11:49:40

...

Or in other words - if I stop the playback right after a dropout, and resume it after approx. 30 seconds, the next dropout occurs right away.

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Answer 3

Kay L. Author

Level 1

12 points

Nov 13, 2022 6:56 AM in response to Kay L.

Ok, so apparently I'm not completely alone with this, but I would have thought that much more people must have seen this until now. Given that the issue is not an individual HW fault of some individual units, which I think is quite unlikely.

Given the (so far) low number of "me too" clicks I don't think that this will be fixed shortly. So I will return the device for now and stick to the 2021 model. I will give it another try once this issue has been a) confirmed and b) fixed.

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Answer 4

Kay L. Author

Level 1

12 points

Dec 14, 2022 5:42 AM in response to alexprs86

Hi Alex! Not exactly sure what you mean, but when you say that you have "exact" the same issue "except" for the dropouts, then your issue would be something different apparently, because for me, the dropouts are THE ONLY issue I have... ;) Or "had" to be precise, because I returned the device as said back then.

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Answer 5

Dreyesbo

Level 1

0 points

Dec 19, 2022 3:48 PM in response to Kay L.

Heya Kay,

I have basically the same issue, with a couple of differences — mine is every 60 seconds, and on an LG C1. My Atmos content plays well, fortunately. It only happens when the AppleTV outputs Multichannel PCM 5.1.

Example titles from my iTunes Library purchases: Inception (5.1, drop every 60 secs); Scott Pilgrim (Atmos, no drop), old TV Show (Stereo PCM, no drop) Same with apps, Netflix for example — Hunt for Red October from 1990 (5.1, drop); Enola Holmes 2 (Atmos, no drop.); Life of Brian from 1979 (Stereo PCM, no drop)

I just troubleshooted with Sonos support fairly thoroughly, and that led me here, so thank you for opening this.

Your note about it being real time also applies to me. Paused right after the dropout, unpaused after 50 seconds and the drop happened right on cue 10 seconds later. So very easily reproducible. Switching to Dolby Digital on ATV solves it, but will mean going to Settings a lot.

I also replaced my 2021 AppleTV for this one, though I’ll keep it hoping for a software update. Will reply here if it ever gets fixed with an update.

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Answer 6

Kay L. Author

Level 1

12 points

Dec 20, 2022 3:00 AM in response to Dreyesbo

Thanks for your reply. Finally a proof that I wasn't seeing ghosts. Or "hearing" for that matter... :D

I was really sure that this is a common issue with that device, but if that would be the case, there should be way more reports by now. Even if the issue is limited to Sonos users. I'm sure there are lots of Sonos users with a new Apple TV out there.

So maybe it's not a common issue actually, but a few one-off's only...

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Answer 7

Jan 1, 2023 11:34 AM in response to Kay L.

I have new 4K Aplle TV 128gb Attached to Samsung TV and soundbar with audio drops across all apps it seems. ATV is updated and have tried mutiple audio stettings with no change

Any help apreciated

Mike

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Answer 8

jotho79

Level 1

13 points

Jan 2, 2023 7:56 AM in response to Normandog35

I have the same issue. I think the problem started with the last few updates from Apple TV. I have the first generation Apple tv 4k. The only time it displays correctly, is for atmos. Anything that is streaming with Dolby Digital 5.1 comes out PCM or Multi PCM 5.1

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Answer 9

Feb 8, 2023 9:20 AM in response to Dreyesbo

Hi all,

This is exactly what I was looking for, as it has been driving me nuts for the past few days.

I have exactly the same issue as Dreyesbo, dropouts every 60 seconds on Multichannel PCM 5.1, with the only solution being switching to Dolby Digital 5.1 on the Apple TV.

Setup is an LG C1, Sonos Beam 2nd Gen, with rears and sub, and the latest Apple TV 4K 2022.

Hopefully there is an update soon that will fix it.

The upside of this is that Dolby Digital 5.1 sounds much better than Multichannel PCM 5.1 on my setup.

Best,

C.

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Apple TV 4k 2022 and Multichannel PCM - audio dropout every 40 seconds

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