Dolby Atmos releases

Hello. I know for a fact there are some releases from, for example, Apple Music, which offer a Dolby Atmos version of the audio.

This version of the audio contains audio “objects” which are mapped to a virtual, spatial point from which the listener is supposed to perceive the audio. This is then converted and mapped to whatever multichannel/surround speaker setup the listener has.

Thus, obviously, it is not the same master, nor the same recording anyways, since we already make a point to separate stereo from surround. However, we do not make the same distinction for DTS vs. AC3, because they are different codecs that are however used to encode the same audio, lossily.

So, what do we do? For an example [though there may be examples in downloadable audio, or physical Blu-ray media, none of which I know of anyways, so if you have an example…] we have the just released re-recording of Taylor Swift’s album “Red”, in Apple Music, and the corresponding MusicBrainz release entry. We know the release has Dolby Atmos and spatial audio because it is listed under “audioTraits” on the source code of the webpage for the release, on Apple Music.

However! None of this audio data is listed on the MusicBrainz entry. If not to tag the music, we should at least provide information, no? I’m surprised the Atmos recordings aren’t listed already because Taylor Swift is an extremely popular artist right now, so I’m just left to assume nobody has thought about it, or at least the topic hasn’t been touched here in the forum. We should tackle the topic while it’s still lukewarm (it isn’t a hot topic. It has cooled down a bit, honestly.)

What do?

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Dolby Atmos recordings should have a different mixing engineer credited than the original stereo recording. By standard practice, different credited people with noticeable audible differences makes a new MB Recording.

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What do we do if the mixing engineer is the same? Because regardless of the person who mixed it, the two [three] versions should sound very different, as the channel setup itself is completely different.

Also, it is a different “artistic” product as the rationale for the placement of every object in the mix is completely different, which results in a [excuse the redundancy] completely different product as well.

With spatial audio things get slightly trickier, because it is translated as binaural audio when using a headset. So the stereo-spatial mix is based on the Atmos mix, not the regular stereo mix, which is offered as well (and is actually usable on an stereo speaker setup).

These are all different recordings because the mix is different.

  1. Stereo.
  2. Spatial, converted to binaural audio, for headset
  3. Dolby Atmos, converted to binaural audio, for headset.
  4. Spatial, for surround home theater setup.
  5. Dolby Atmos, which is converted on the fly, for surround home theater setup.

In my opinion, 2/4 and 3/5 are the same recording because the mixing is supposed to be perceptibly similar. [edit: And stereo vs. binaural are different mixes as well, however the latter is automatically generated on the fly and is not actually offered by any standard method as-is.] Added to that, the conversion is automatic. The latter of which should be, in my opinion, treated no different than surround audio in DTS vs. Dolby, the two of which MusicBrainz does not usually make a distinction for.

I am not sure if I understand why these are all listed as separate things. My understanding from Spatial Audio vs Dolby Atmos: What's the Difference? is that “Spatial Audio” is something the operating system does, and it’s not a way that a mixing engineer would finish a song.

“Dolby Atmos” is also software you can find on Windows computers and Android smartphones, but here we’re referring to the way a mixing engineer would assign the instrument/vocal subtracks to the Dolby Atmos channels/positions.

Additionally, if the operating system is converting/downmixing/upmixing the Dolby Atmos file on the fly, this is not a new recording.

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My mistake. Wikipedia redirects “spatial audio” to “surround sound”.

I’m just listing different mixes, including automatic ones. It’s just to point out the latter should still not be separate recordings.

Dolby Atmos is a proprietary standard for storing the audio in a codec, and then delivering it to an arbitrary number of speakers. The software is just an implementation of the standard.

The implementation of the audio setup nonwithstanding, the Dolby Atmos version of the recording should be a different recording, which is where the tracklist comes in, as these are not listed.

All I’ve been doing, because the recordings all show up as the same stereo recordings on Apple Music, is just putting into the annotation of the release “Spatial Audio & Dolby Atmos available on Apple Music”. Not sure if we should start doing double recordings like we do with SACDs, DVDs, etc that have more channels.

I would simultaneously like and dislike this. Because while ugly, we’d at least acknowledge this.

Maybe we should have multiple types of digital media, like we have multiple types of SACDs. It’s kinda analogous, what both of these mediums are doing lately.

[Or am I going too far?]

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I’d also add (Dolby Atmos) to the disambiguation on the Recordings. We do this on Quad and 5.1 mixes. Makes the recordings stand out better.

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The main problem I see though is that most of the Spatial Audio Apple Music releases are indistinguishable from the other digital releases that share the same barcodes, labels, countries, etc. They only way you even know is to look at the “view data source” for audio traits. So, we might have to separate out those once we know that release has that, but I don’t see many editors doing that. For such a big deal, they really aren’t advertising it with logos, etc, like they used to do. Well, they do in the app on my iPhone, but not on the websites.

I assume the digital file can tell you how many channels it has? Shop may be rubbish with details, but the important item would be the media itself. Yes, that will rely more on the owners of the actual music files to identify them, but this is the same with SACDs. We don’t ask Amazon to tell us about the SACD they sell - we look at the actual CD.

That’s what I assume. If you have the proper hardware, i.e. Airbuds, speakers, etc. than it will give you an option on what to listen too. But their hardware is so expensive. SACDs on CD players, I assume only show what the CD can play, not everything on the disc. I’ve tried to get more technical info on Spatial Audio, but they blur the lines between Dolby Atmos, etc. I’ve seen Dolby Atmos 7.1, etc on DVDs, but Spatial Audio only uses 2 speakers when they are using airbuds and yet that is also all powered by Dolby Atmos. So, if it’s only 2 speakers is it really mixed differently or just some sort of gimmicky Apple trick?

If we’re being literal, up to 128. So that’s essentially useless information, because the actual number of channels in the end depends exclusively on your setup.

Dolby Atmos - Wikipedia :

Dolby Atmos technology allows up to 128 audio tracks plus associated spatial audio description metadata (most notably, location or pan automation data) to be distributed to theaters for optimal, dynamic rendering to loudspeakers based on the theater capabilities.

From what I’ve seen, software without Atmos support falls back to reporting 6 channels.

If it is playing back through two speakers, you’ll get an alternate sound. On a PC I can interrogate the digital file with something like MediaInfo and ask what it holds. So if it has 128 channels in the container, then that is what it is. And should be documented that it is an Atmos file.

It the playback equipment only has two speakers, you get a two speaker version to listen to. Just like when you listen to a stereo record on a mono system. We would document the record is stereo, not the limitations of the playback hardware.

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No. On Spatial Audio, it literally only uses 2 speakers!!! That’s the deal. Gives you the feel of surround sound on only 2 speakers. Only Airbuds (headphones) and their home speakers can use it.

If it’s speakers it’d be mixed differently to headphones because of binaural audio.

Binaural audio is a method for simulating what the ears perceive when hearing natural noise. Both ears actually perceive slightly different sound, and those differences are used for positional mapping in our mind.

The end result is that you hear that the sound comes from around you. (I’ve heard binaural audio, and it works bizarrely well. It’s trippy.) It’s still stereo, but the mix is very different.

This doesn’t work on speakers though.

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Ok. Wow. This is why I only put it in the annotation.

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The OP was talking about Atmos which is a multi-channel encoding used by cinemas. So your playback hardware will chose how to present that audio to you.

If you have headphones - you’ll get two speakers. If you sit and listen to it on a home cinema system with 16 speakers - you’ll get a different experience. Same audio track.

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But Apple Music, what the OP was talking about doesn’t have Dolby Atmost as a separate thing. They say that it’s all Spatial Audio mixed using Dolby Atmos. I’m not sure those files are true surround sound like the Dolby Atmos is on DVDs, et.

I’m probably reading the Apple page on it wrong. Like I said, it was very confusing.

I don’t know if they sell the file. I think it’s only for streaming.

As for the channels, well…

Dolby Atmos technology allows up to 128 audio tracks plus associated spatial audio description metadata

So that’s that. It doesn’t have channels. The channels are rendered in real time as it plays the file. If you play the file in unsupported software, I think it only reports six channels for backwards compatibility.

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