How to get surround sound out of Apple Music Spatial Audio?!

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Cheezmo

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I have analyzed Apple's Atmos streaming. Yes, it's lossless. Yes, it sits in a 5.1 LPCM container. But some of these mixes are pretty bad when used on a proper surround system, that's the issue.
You are analyzing what the AppleTV is sending to the AVR, everyone is in complete agreement that is lossless. They decode the lossy stream and send it to the AVR lossless (they do that with movies also and no one has ever claimed that Apple has lossless movie audio). You need to analyze what the AppleTV is receiving over the internet (shouldn't be too hard to see what the bitrate is on that and that would make it pretty clear).
 

Mr. Afternoon

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You are analyzing what the AppleTV is sending to the AVR, everyone is in complete agreement that is lossless. They decode the lossy stream and send it to the AVR lossless (they do that with movies also and no one has ever claimed that Apple has lossless movie audio). You need to analyze what the AppleTV is receiving over the internet (shouldn't be too hard to see what the bitrate is on that and that would make it pretty clear).
Well, there's is another way to verify, which some people I know have done, but it's not exactly legal, so I won't be touching that.
 

Cheezmo

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Well, there's is another way to verify, which some people I know have done, but it's not exactly legal, so I won't be touching that.
Another way to verify, in the Music application there is an option to download the Atmos version. The Atmos version of The Beatles Come Together is 33.8Mb. My stereo ALAC CD rip is 23.3Mb. My 5.1 ALAC multichannel rip from the Blu-ray is 253Mb.

I verified that the Mac downloads lossless by downloading a track from CCR's Cosmo's Factory which was 24/192 and 167Mb.

Clearly the Atmos version as downloaded is lossy. Is it possible they stream something different to the AppleTV? I guess so but highly doubt it.
 

Mr. Afternoon

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Another way to verify, in the Music application there is an option to download the Atmos version. The Atmos version of The Beatles Come Together is 33.8Mb. My stereo ALAC CD rip is 23.3Mb. My 5.1 ALAC multichannel rip from the Blu-ray is 253Mb.

I verified that the Mac downloads lossless by downloading a track from CCR's Cosmo's Factory which was 24/192 and 167Mb.

Clearly the Atmos version as downloaded is lossy. Is it possible they stream something different to the AppleTV? I guess so but highly doubt it.
We'll see. I've gotten news that it got broken wide open already and I'm waiting for more news.
 

bracelis

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Another way to verify, in the Music application there is an option to download the Atmos version. The Atmos version of The Beatles Come Together is 33.8Mb. My stereo ALAC CD rip is 23.3Mb. My 5.1 ALAC multichannel rip from the Blu-ray is 253Mb.

I verified that the Mac downloads lossless by downloading a track from CCR's Cosmo's Factory which was 24/192 and 167Mb.

Clearly the Atmos version as downloaded is lossy. Is it possible they stream something different to the AppleTV? I guess so but highly doubt it.
I already said in a previous post below that people might be disappointed if they learn that it's the same lossy DD+ as Tidal, after the comments from several people that the Apple quality seems much better than Tidal.

I captured the raw network data packets on the Apple TV's Ethernet connection and played Come Together (Atmos) -- it's 25MB (see screenshot).

The song is 4:20 long (260 seconds).
( 25,000,000 byes / 260 seconds) x 8bits = 769,230 bits per second

So it's 768 kb/s.

come_together.jpg
 
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MidiMagic

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The one on the left was on the top, and the one on the right was on the bottom, and the one in the middle got a broken arm, and the one on the rear said "Oh dear!"

The chaos I am seeing among the various digital formats is chasing me away from anything digital beyond the CD. This won't work with that! You have to have my software to play my file, You have to carefully tweak this to make it work. That supposedly works with this unless you have the other.

I wonder how much of this mess is everyone enforcing his own patent.
 

Mr. Afternoon

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I already said in a previous post below that people might be disappointed if they learn that it's the same lossy DD+ as Tidal, after the comments from several people that the Apple quality seems much better than Tidal.

I captured the raw network data packets on the Apple TV's Ethernet connection and played Come Together (Atmos) -- it's 25MB (see screenshot).

The song is 4:20 long (260 seconds).
( 25,000,000 byes / 260 seconds) x 8bits = 769,230 bits per second

So it's 768 kb/s.

View attachment 67971
:oops: Looks like I'm wrong, and so are other people.
 

jonfo

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:oops: Looks like I'm wrong, and so are other people.
Yes, and no. As @bracelis documents, the incoming stream is indeed a DD+ at the max rate of 768Kbps.

My understanding of what the ATV4K does is the following:
  • De-muxes the audio and video streams
  • Routes the video stream to the HDMI, with any necessary conversions, or none, based on settings and EDID info from the target device
  • Decodes the audio stream elemental parts, in the case of DD+ into the (up-to) 7.1 LPCM bed channels and the encoded Atmos objects data stream.
  • It then (again limited by EDID info) passes the LPCM to the target, and using Dolby MAT 2.0, transfers the Atmos object data as well.

    So yes, the ATV4K is sending 24/48 LPCM at all times, regardless of source material, as that is how they avoid audio drop-outs when inserting navigation feedback or when changing sources (eg Netflix -> Apple Music) on the set-top. Remember, Apple is about user experience first, audio snobbery second.​

Note: MAT 2.0 is a codec where the source (ATV) encodes a mix of signals, in this case the (up-to) 7.1 LPCM bed and the Atmos objects streams into an 8 channel 16/192 'carrier' LPCM stream whose headers tell the receiver that this is a MAT 2.0 encoded stream.
So with 3MBs per 'channel' * 8 = 24MBs (and that's bytes, not bits) we have very high-capacity data transport over the HDMI link.
MAT can be used to send lossless content if the source has it, it can even propagate TrueHD compressed lossless IIRC.
So at some future date, Apple Music *could* stream TrueHD Atmos, and the ATV4 will re-package it into MAT 2.0 (or 2.1), as there is plenty of bandwidth over HDMI.

So technically, the ATV is not always sending the same LPCM stream, it transitions between 'basic' LPCM where the data is truly the audio at x bit-depth, and MAT LPCM. But since the ATV is encoding the MAT stream, it can overlay UI feedback into the audio stream before encoding.
 
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OregonSurround Fan

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I posed a question regarding this on a different thread, but it's worth repeating here - and it deals with the source material for surround sound, as mentioned above. The Dolby Atmos product Apple is selling is an upmix from the 2.0 source, correct? They're not full-resolution surround mixes from the original multitrack masters, right? I've done some A/B testing, and the Apple product is not even close to, say, Fleetwood Mac's 5.1 DVD-A of Rumours - or the more recent Atmos anniversary release of INXS's Kick. On those albums, the engineers remixed all of the channels separately in full resolution from those original multitracks. Please let me know if I'm missing something in my settings.
 

EricKalet

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I posed a question regarding this on a different thread, but it's worth repeating here - and it deals with the source material for surround sound, as mentioned above. The Dolby Atmos product Apple is selling is an upmix from the 2.0 source, correct? They're not full-resolution surround mixes from the original multitrack masters, right? I've done some A/B testing, and the Apple product is not even close to, say, Fleetwood Mac's 5.1 DVD-A of Rumours - or the more recent Atmos anniversary release of INXS's Kick. On those albums, the engineers remixed all of the channels separately in full resolution from those original multitracks. Please let me know if I'm missing something in my settings.
There are no upmixes from 2.0. All come from multi-track masters. From what I've read and understand, some engineers/mixers are mixing using full 7.1.4 Atmos systems and others are mixing using headphones! That probably makes a huge difference in what we are hearing when switching from song to song and hearing completely different results while expecting an immersive and discrete experience.

Rumours and Kick can't be compared because there is no Atmos mix released on Apple Music to compare to. Even such a comparison might not yield favorable results because the engineers creating the Atmos mixes may be going for a different result than what the previous engineer who created the DVD-A or Blu Ray was going for (example being Rush - Tom Sawyer & Limelight and Guns and Roses - Sweet Child O' Mine & Welcome to the Jungle). Some Atmos mixes should be identical to their physical disc counterparts - such as the recent Lennon - Plastic Ono Band or Yello - Point.
 

OregonSurround Fan

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There are no upmixes from 2.0. All come from multi-track masters. From what I've read and understand, some engineers/mixers are mixing using full 7.1.4 Atmos systems and others are mixing using headphones! That probably makes a huge difference in what we are hearing when switching from song to song and hearing completely different results while expecting an immersive and discrete experience.

Rumours and Kick can't be compared because there is no Atmos mix released on Apple Music to compare to. Even such a comparison might not yield favorable results because the engineers creating the Atmos mixes may be going for a different result than what the previous engineer who created the DVD-A or Blu Ray was going for (example being Rush - Tom Sawyer & Limelight and Guns and Roses - Sweet Child O' Mine & Welcome to the Jungle). Some Atmos mixes should be identical to their physical disc counterparts - such as the recent Lennon - Plastic Ono Band or Yello - Point.
Very interesting! I'm going to be curious to learn more. Collecting 5.1 has been an obsession for about 15 years (the current tally is roughly 200 titles, but I'm always looking for more). Bottom line: This is of great interest to me. I clearly need to do more homework, and figure out how to get the Apple content from my MacBook to my DAC and home system. I'm currently using VOX to play most of my titles through and HDMI cable, and it works perfectly. If you have any tips for running the Apple into a home system, please point me in that direction - or to a different thread. Thanks again.
 

EricKalet

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Very interesting! I'm going to be curious to learn more. Collecting 5.1 has been an obsession for about 15 years (the current tally is roughly 200 titles, but I'm always looking for more). Bottom line: This is of great interest to me. I clearly need to do more homework, and figure out how to get the Apple content from my MacBook to my DAC and home system. I'm currently using VOX to play most of my titles through and HDMI cable, and it works perfectly. If you have any tips for running the Apple into a home system, please point me in that direction - or to a different thread. Thanks again.
After a quick look at the Vox website, I’m not entirely certain that player supports Atmos. From my experience and others experience everything in the chain has to support Atmos or it doesn’t work.

According to Apple’s FAQ…it appears you won’t get the full Atmos from a Mac…
 

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bracelis

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This is what I've gathered so far:

* Apple TV -----> Receiver ----> multi-channel speakers (including height channels)
Today, this is the only way to get proper Atmos with external speakers.

* Mac ---> USB multi-channel audio interface ---> multi-channel speakers (5.1, no height channels)
So you don't get the full Atmos.

And you don't get Atmos, either, when connected to HDMI / Receiver.


* On Windows, there is currently no Apple "Music App" available.
There is an Itunes app (for watching Movies and listening to music), but this is an outdated app, so it has not been updated to support the recently launched Atmos or lossless on Apple Music.


* Other methods posted in previous post (earphone, internal speakers)


* Android mobile, using Music App 3.6 Beta
Atmos (headphone)
I have tried this on a Samsung phone, and it shows Atmos while playing the song, if I have a (cheap) DAC connected to the phone's USB port.
 
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