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Apple lossless official announcement

DavidMcRoy

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there is a member one page before this one saying that they got multichannel output by plugging a multichannel DAC to their Mac via USB.

Multichannel, but is is really Dolby Atmos? I don’t know.
 

DimitryZ

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Multichannel, but is is really Dolby Atmos? I don’t know.
Same question here. Would someone with such knowledge be so kind as to do a short list of the several 3-D formats being now offered by the streaming services and what they do?
 

chelgrian

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But we were actually talking about the Atmos rendering, so the way the Atmos positional audio track is converted to a stereo system. That is a totally different animal.

For iOS/iPadOS Apple are almost certainly detecting the output device then streaming a pre-rendered two channel version which is either a binaural version with an HRTF used if listening on AirPods or some custom transform for the known geometry of the internal speakers in the supported phones or computers.

Tea leaf reading suggests that the only way to get the Dolby Digital Plus and externally decode it currently is via the HDMI out of an Apple TV 4K or later.
 

Blaspheme

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there is a member one page before this one saying that they got multichannel output by plugging a multichannel DAC to their Mac via USB.
That may have been me: so I can see multi-channel output from Mac via USB to an 8 channel DAC, but don't have an AVR or processor to do Atmos from HDMI, which appears to be a requirement. In other words: 7.1 from 8 channels yes, but 5.1.2 no (that's looking at speaker configuration in Audio Midi Setup on macOS with the relevant output device selected).
Multichannel, but is is really Dolby Atmos? I don’t know.
See above, Mac to multi-channel DAC doesn’t deliver Atmos. I imagine if I had Atmos-capable AVR or processor then that would work from macOS TV or Music apps on suitable source material.
 

eas

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For iOS/iPadOS Apple are almost certainly detecting the output device then streaming a pre-rendered two channel version which is either a binaural version with an HRTF used if listening on AirPods or some custom transform for the known geometry of the internal speakers in the supported phones or computers.
I'm not sure I'm understanding you here. Are you suggesting that Apple streams a different pre-rendered two channel version for each supported phone or computer? Or are you suggesting that they stream one two channel version that is then further processed for the target output device?

I'm not sure what's going on, but there may be some clues for us.

The Atmos content can be downloaded, as well as streamed. I don't know what's downloaded on an iOS device. On a Mac, thought, the download track is stored on disk as a package or bundle, basically a directory with special metadata so it is presented as a single file in the Finder. However, it's easy to open it up and see what's inside.

What one finds is a couple of XML files and four directories. Two of the directories appear to contain audio data, contained in .frag files. In each case, based on filenames, the data seems to be broken up into files holding 14.9769s of audio. In one directory each file is about 479kb in size, which works out to ~256kbps. The files in the other data directory are 1.4mb, or ~765kbps.

As to how they are used, I don't know.

I do know that, Mac, or iOS, the Atmos download has to provide for binaural (AirPods/headphones), "spatial" with internal speakers, and stereo (headphones, internal speakers, any other output). Apparently multichannel output is not supported on a Mac (if it is, Apple doesn't explain how to use it).

I know that if you've downloaded the Atmos version of a track and then disable Atmos playback while keeping the download, Apple Music will play back a 256kbps AAC stereo version (no matter whether your playback settings specify Lossless). Could the stereo, binaural and "spatial" internal speaker versions be rendered from the same 256kbps file? Could a stereo version be rendered from a two-channel device-specific 256kbps Atmos file? What are the larger files for?

It seems to me that the simplest explanation is that the Atmos downloads contain 256kbps stereo version and a higher-bit-rate multichannel Atmos version that gets rendered for either binaural or device speakers. Without a download on disk, only one or the other are streamed from Apple to the device.

Or maybe not. My Mac is a 2016 MacBook Pro and Atmos playback on the internal speakers isn't supported. Perhaps if I had a supported model (MacBook Pro (2018 model or later), MacBook Air (2018 model or later), or iMac (2021 model)) Music would download a third set of audio data, one tailored for the device speakers. Does anyone with a supported system care to check? Chose the Apple Music preference to download Atmos. Find an Atmos track, download it. Find the download in your Music folder ("Info" on the track should show the download location). Right click on it and choose "Show Package Contents". There will be at least four directories, at least two of them will contain .frag files. Do you find a third with .frag files? Let us know.
 

DavidMcRoy

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That may have been me: so I can see multi-channel output from Mac via USB to an 8 channel DAC, but don't have an AVR or processor to do Atmos from HDMI, which appears to be a requirement. In other words: 7.1 from 8 channels yes, but 5.1.2 no (that's looking at speaker configuration in Audio Midi Setup on macOS with the relevant output device selected).

See above, Mac to multi-channel DAC doesn’t deliver Atmos. I imagine if I had Atmos-capable AVR or processor then that would work from macOS TV or Music apps on suitable source material.

I have a Dolby Atmos AVR running a 7.1.4 system, and I have iPhones, iPads and a Mac Mini. Alas, I don’t have an Apple TV4K. (That’ll be my next purchase.) As I’ve stated before, and I guess it bears repeating for some, Apple’s own propaganda suggest that you need an Apple TV4K running the latest version of tvOS and a Dolby Atmos decoder with an HDMI input to get at the “flavor of” Dolby Atmos on Apple Music required for 7.1.4 (or what have you) immersive speaker playback.
 
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Blaspheme

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I'm not sure I'm understanding you here. Are you suggesting that Apple streams a different pre-rendered two channel version for each supported phone or computer? Or are you suggesting that they stream one two channel version that is then further processed for the target output device?

I'm not sure what's going on, but there may be some clues for us.

The Atmos content can be downloaded, as well as streamed. I don't know what's downloaded on an iOS device. On a Mac, thought, the download track is stored on disk as a package or bundle, basically a directory with special metadata so it is presented as a single file in the Finder. However, it's easy to open it up and see what's inside.

What one finds is a couple of XML files and four directories. Two of the directories appear to contain audio data, contained in .frag files. In each case, based on filenames, the data seems to be broken up into files holding 14.9769s of audio. In one directory each file is about 479kb in size, which works out to ~256kbps. The files in the other data directory are 1.4mb, or ~765kbps.

As to how they are used, I don't know.

I do know that, Mac, or iOS, the Atmos download has to provide for binaural (AirPods/headphones), "spatial" with internal speakers, and stereo (headphones, internal speakers, any other output). Apparently multichannel output is not supported on a Mac (if it is, Apple doesn't explain how to use it).

I know that if you've downloaded the Atmos version of a track and then disable Atmos playback while keeping the download, Apple Music will play back a 256kbps AAC stereo version (no matter whether your playback settings specify Lossless). Could the stereo, binaural and "spatial" internal speaker versions be rendered from the same 256kbps file? Could a stereo version be rendered from a two-channel device-specific 256kbps Atmos file? What are the larger files for?

It seems to me that the simplest explanation is that the Atmos downloads contain 256kbps stereo version and a higher-bit-rate multichannel Atmos version that gets rendered for either binaural or device speakers. Without a download on disk, only one or the other are streamed from Apple to the device.

Or maybe not. My Mac is a 2016 MacBook Pro and Atmos playback on the internal speakers isn't supported. Perhaps if I had a supported model (MacBook Pro (2018 model or later), MacBook Air (2018 model or later), or iMac (2021 model)) Music would download a third set of audio data, one tailored for the device speakers. Does anyone with a supported system care to check? Chose the Apple Music preference to download Atmos. Find an Atmos track, download it. Find the download in your Music folder ("Info" on the track should show the download location). Right click on it and choose "Show Package Contents". There will be at least four directories, at least two of them will contain .frag files. Do you find a third with .frag files? Let us know.
That was interesting. I didn't think of just playing via the MBP speakers (a 2019 16"). I downloaded the first Taylor Swift track the 1 from folklore (the album displays Lossless, Dolby Atmos and Apple Digital Master labels in the macOS Music app, and the cover art has animated flocks of birds and butterflies flying about). The package contains six items including two folders with music data as .frag files totalling 20.3 and 6.7 MB respectively, so Atmos and AAC I guess. Get Info in Music app says this downloaded track is "Dolby Atmos".

Playing though the laptop speakers delivers a somewhat convincing spatial effect: the vocals and some foreground instrumentation appears to come from the laptop, other instrumentation appears to come from the front of the room. I had to get up and check to be absolutely certain there was no sound coming from the main stereo speakers or TV (even though I could clearly see the output device indicated was "MacBook Pro speakers"). I can imagine people being impressed by this.

I disabled Atmos downloads in Music preferences and downloaded the same track again. This time there were five items in the package (one less) and just one with music data as .frag files, but adding up to 39.1 MB. Bigger! ALAC higher-res perhaps? Get Info in Music app says this one is "Lossless Audio".

Edit: but having said that, I tried turning off Atmos playback and the spatial effect wasn't much different. Then I deleted and downloaded again to be sure (Music app seems to keep tabs on the file even if you move/rename, as far as I got anyway). I haven't listened to the MBP speakers for a good while, I forgot they did that—don't hire me to test this shit, obviously. But my guess is when you set macOS Music app to download Atmos, you get the AAC along with that, but you don't appear to get the lossless stereo file (ALAC) as well.
 
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abdo123

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That may have been me: so I can see multi-channel output from Mac via USB to an 8 channel DAC, but don't have an AVR or processor to do Atmos from HDMI, which appears to be a requirement. In other words: 7.1 from 8 channels yes, but 5.1.2 no (that's looking at speaker configuration in Audio Midi Setup on macOS with the relevant output device selected).

See above, Mac to multi-channel DAC doesn’t deliver Atmos. I imagine if I had Atmos-capable AVR or processor then that would work from macOS TV or Music apps on suitable source material.

why would you come to this thread and say ‘my multichannel DAC works (as intended)’ when there is no multichannel content on Apple music?

you didn’t think people will interpret that as you successfully getting multichannel output from decoding Dolby Atmos?
 

Blaspheme

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why would you come to this thread and say ‘my multichannel DAC works (as intended)’ when there is no multichannel content on Apple music?

you didn’t think people will interpret that as you successfully getting multichannel output from decoding Dolby Atmos?
You've quoted my post which said "Mac to multi-channel DAC doesn’t deliver Atmos". The context is that macOS TV app provides multi-channel content, Atmos and otherwise. So a suitable Mac can play a 5.1 or 7.1 soundtrack via a DAC without an Atmos licence/decoder. People here have been gradually figuring out what the Music app does—apparently not the 'otherwise' I was hoping for. Movies being much bigger packages, I'm guessing they pack all the audio options in. For Music downloads, it looks like the opposite approach. Music app appears to provide multichannel content, but only via Atmos.
 
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mononoaware

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I like to think everyone here is aware that any company that pays enough can stick the term “Atmos” to their product and then include it in the product marketing.

First it was seen in Stereo (2.0) driver design Soundbars, Mobile phones then claimed “Atmos” from just their 2 built-in speakers, now headphones are claiming to give you “Dolby Atmos”.

https://support.apple.com/en-au/HT212182

After reading Apple’s own page about “Spatial audio and Dolby Atmos” there are no technical claims about giving you a true Dolby Atmos experience or the decoding of 7.1 and higher channel content.

As far as I am concerned “Dolby Atmos/Spatial audio” by Apple is just a trick of digital processing (splitting audio frequency content into virtual channels and adding certain effects) just like it is with entry-level Soundbars and some recent Mobile-phones.
It is made to fool the average consumer into thinking they are experiencing true surround sound Dolby Atmos experience.

The only “new” thing I can see here is with spatial audio it uses “Dynamic head tracking” to keep those digitally processed simulated channels floating in fixed points around you.

The only device I can understand getting true 7.1 and higher signal is the Apple TV 4K since it falls into “home cinema” category, but then it already must have the basic ability to decode surround, so they just add the “spatial audio” head tracking.

Just to be clear, when you open Apple Music on your phone and play a song in Dolby Atmos to my understanding you are NOT getting 7.1 channel signal and decoding, you are getting 2.0 stereo with algorithm effects applied that Dolby deemed “good enough” to be considered Atmos (most likely the processing is done at Apple and not on your device).
And when you use AirPods to listen to it all you get is head tracking in a simulated experience.

Am I missing some kind of crucial information about Apple’s claims?

Edit: also to the comment that said Dolby Atmos version is quieter (by 10dB?) the link above says to turn on “sound check” and it will fix it.
 
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abdo123

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Am I missing some kind of crucial information about Apple’s claims?

I think you have some sort of misunderstanding of how Atmos works, it's an object based audio format which any audio device can be certified to decode. it's not a guarantee for the best experience possible.

For example an Apple TV top-up box can pass down Dolby Atmos tracks to your AVR which will decode Atmos to the best possible experience your setup allows.
 

chelgrian

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Am I missing some kind of crucial information about Apple’s claims?

Search for 'Head Related Transfer Function' usually used for headphones but similar things can be done for precisely known geometries of speakers such as the internal ones on a Mac.
 

mononoaware

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I think you have some sort of misunderstanding of how Atmos works, it's an object based audio format which any audio device can be certified to decode. it's not a guarantee for the best experience possible.

Yes I understand that, what I am saying is something audio related that functions completely differently to “real” Atmos decoding can have the “Atmos” logo on it.
(e.g some cheap product that just plays 2.0 stereo content but processes the audio with its own method to what it claims as giving you the “Atmos” experience, provided the company pays enough to Dolby and Dolby agrees the end result is good enough)
 
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abdo123

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Yes I understand that, what I am saying is something audio related that functions completely differently to “real” Atmos decoding can have the “Atmos” logo on it.
(e.g some cheap product that just plays 2.0 stereo content but processes the audio with its own method to what it claims as giving you the “Atmos” experience)

they're both the 'real' Atmos experience.

Lets say I play a game on my Playstation 5, is my experience any less real if I play using headphones or in a full fledged Home Cinema?
 

chelgrian

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The package contains six items including two folders with music data as .frag files totalling 20.3 and 6.7 MB respectively, so Atmos and AAC I guess. Get Info in Music app says this downloaded track is "Dolby Atmos".

Interesting assuming the smaller one is 256kbit AAC then that means the average bitrate of the Atmos file must be around 768Kbit/s if it's encoded using E-AC3 or AC4 is the next interesting question.
 

mononoaware

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Search for 'Head Related Transfer Function' usually used for headphones but similar things can be done for precisely known geometries of speakers such as the internal ones on a Mac.

I understand how one can be tricked into experiencing surround sound.
Just search 8D audio on YouTube, an example of how simply it can be done.
 

mononoaware

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they're both the 'real' Atmos experience.

Lets say I play a game on my Playstation 5, is my experience any less real if I play using headphones or in a full fledged Home Cinema?

I am talking about the source signal. There is real Dolby which is mixed and then compressed to allow for decoding in the home.
Then there is “Dolby” where it is simulated sound coming out of whatever product is willing to pay the most and “Dolby” is willing to take the hit to their reputation by license the use of the logo (or maybe they don’t even use the logo, they just claim “Dolby Atmos”).
In other words when a company lacks providing details about specifics of their “Dolby Atmos” claim, I assume it is the latter.
 

abdo123

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I am talking about the source signal. There is real Dolby which is mixed and then compressed to allow for decoding in the home.
Then there is “Dolby” where it is simulated sound coming out of whatever product is willing to pay the most and “Dolby” is willing to take the hit to their reputation by license the use of the logo.
In other words when a company lacks providing details about specifics of their “Dolby Atmos” claim, I assume it is the latter.

There is one kind of Atmos, and it's the earlier. it's just Dolby will never provide a digital stream of the undecoded tracks without HDMI copy protection protecting it. So for the case of our phones it's instantly decoded to whatever speaker setup they have.
 

ENG

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About music audio streaming. So far I joined Apple Music and connected an iPhone 7 to my Topping D90 with Apple Lightning to USB Camera Adapter. No problem, very fine sounding (subjektive). But how to control the playing iPhone 7 remote from my iPhone X or iPad Pro 11?
 

mononoaware

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There is one kind of Atmos

I agree. That is what I mean by “real” Atmos.

Other products claiming “Dolby Atmos” is not the same thing. And I think it is a slippery slope for Dolby to license use of their name so easily.
As some who reported listening to Dolby Atmos version on Apple music just sounds like over-processed audio with enhanced bass, because that is exactly what it is.

It is just illusion of surround by processing, and I think it is very likely the virtual 7.1 signals (of Apple Music Dolby Atmos) are not 1:1 the same as the real Dolby 7.1.
 
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