Apple Music Dolby Atmos style [STYLE-2348]

[STYLE-2348] Create medium formats for Apple Music Dolby Atmos releases similar to SACD layers - MetaBrainz JIRA suggests to follow the multi-TOC SACD approach for Apple Music Dolby Atmos releases. There’s been a fair amount of discussion on this topic recently and it seems most people consider this a relatively sensible option but there’s no consensus. I would like to have a discussion about this specific option and why people feel it’s a good or bad idea (feel free to quote from the several previous existing threads as needed, but let’s try to have the discussion in one place).

In principle it seems ok to me - it’s true that it would feel a bit odd when tagging since most people will only have one version, but at the same time, that’s not very different to people tagging a hybrid SACD who only have a CD reader but not a SACD one. But looking forward to hear reasonings in either direction :slight_smile:


No comments about this at all? :slight_smile:

I don’t think “most people” consider this if “there’s no consensus”.

I know I laid out concerns in reply to Spatial audio: new release, new recordings? - #16 by Cheezmo - currently, Apple Music releases would be shared across all other digital platforms with shared identifiers on the basis of stereo audio (assuming that the Apple Music API doesn’t report a unique barcode). By allowing/requiring a separate release to be created that has a stereo medium and a spatial medium, then it causes crazy duplication of releases because other digital platforms only do stereo, not spatial (Spotify/Amazon/etc.)

Most people don’t seem to care about this problem. For example, I’m not seeing an issue when editing Japanese music currently.

Some labels already assign unique barcodes to hi-res releases vs. 16bit/44.1kHz releases, so they might already be reporting a different barcode via Apple Music than they would on Spotify - I don’t know.


Despite my having proposed a solution, I’m not even very sure what the right thing to do is. I think what Apple has done by “overlapping” the Atmos release on top of the stereo release is really stupid so it is no wonder we don’t have a good way of representing it. Especially in situation where just a few tracks are “upgraded” to Dolby Atmos.

But what I do know is that those releases have two sets of recordings and we need to somehow represent that and the dual medium approach seems to be the best we can do right now without some way of associating multiple recordings with a single “track”.


I believe this is currently the best solution to this issue. could probably use some work on the display side, i.e. showing both tracklists as one or something, but I understand that’s outside the scope of this ticket

I don’t know if this issue is as bad as you say it might be… in my editing experience, I’ve rarely come across a Dolby Atmos release (or at least rarely noticed one)

also, since the releases have “different” tracklists (in the form of multiple recordings on the same “track”), I’d argue this is a necessary duplication of releases

I have about 900 Apple releases with Dolby Atmos tracks in my library. That is quite a lot. You haven’t seen them editing because there hasn’t been a good way to add them!

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They have upgraded a ton of them to include Dolby Atmos/Spatial audio on existing releases that before were just straight stereo. They did it without notification, so it’s virtually impossible to know when they were upgraded. I’m starting to come across a bunch that now have them marked this way. Another issue is that we really don’t even know if all the tracks are spatial audio or just some of them. I say this, because on their hi-res releases, many times they’ll mark a release as hi-res and it will literally have only 1 track that is hi-res and the rest are standard on playback using the Apple Music app on my iPhone. So, without them telling us the different ISRCs on each track for the Dolby Atmos mixes, I really am not sure how we can do anything other than just mention it in the annotation. TIDAL actually has Dolby Atmos releases that are standalone releases with their own unique ISRCs for the Dolby Atmos mixes. They are not shared with the stereo release, I don’t think. I’ve never tried to play them as I don’t use TIDAL.


This makes me think it’s pointless for MusicBrainz to try to track this or accommodate it with proprietary schema changes. IIRC, Apple / the labels have been pretty hush-hush about who the mixing engineer is on these kinds of spatial audio “upgrades” anyway.


Yeah, TIDAL mentions the mixers alot on theirs, but I’m not even 100% they are the same recordings that Apple Music uses, because Apple won’t give any information or even ISRCs about them.

I don’t feel it necessarily makes sense to mirror SACDs here - SACDs are weird (I edit a ton of SACDs/multichannel stuff, I can say this :slight_smile:). SACDs follow an actual published standard (Scarlet Book) that explicitly defines “SACD” as (among other things) a thing that supports stereo and multichannel mixes in different physical sectors of the release as part of the format - furthermore if they are hybrids the format is physically layered, not just logically layered. The use of different mediums to indicate multichannel content for a release barely makes sense for SACDs and rapidly loses meaning once you leave that format behind.

“Digital Media” is not a published standard that explicitly defines an optional multichannel component, and “What Apple Is Currently Doing” doesn’t either.

I think it’s better to treat this exactly like we currently do with Blu-ray Audio discs that contain both stereo, Dolby TrueHD 5.1 and Dolby Atmos mixes - with a single medium that lists all unique mixes present. If you have a stereo processor and play one of those discs thru it, you won’t get Atmos (or you’ll get a mixdown). If you play Atmos thru a regular 5.1 TrueHD processor, you get 5.1 TrueHD mixdown - the playback device makes a dynamic decision - that’s effectively exactly the same as what Apple’s doing.

Or I guess to put another way - if we do choose to do something different here than we currently already do with Blu-ray Audio discs that contain both stereo and Atmos mixes of the same content, we should make sure it’s consistent between the two, since practically I don’t see a difference between “Bluray w/Atmos and Stereo” and “Digital Media w/Atmos and Stereo”.

  • If we use one medium for the former, why not use one medium for the latter? (slight pref for this)
  • If we use multiple mediums for the latter, we should use multiple mediums for the former (e.g. Bluray w/ Dolby TrueHD medium type, where the available channel counts are defined by the spec of the carrier format, not the medium)


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