audiomaster
Well-known Member
This is all hopelessly out of date! Most multi-channel formats started out in theaters like Dolby and Imax. Now the SPHERE in Las Vegas boasts 1600 speaker cabinets with a total of 167,000 driving elements! So soon were going to have to buy new hole saws, and a lot more speaker cable! I can hear the comments on this forum in 20 years.Preamble diatribe alert! (Skip to bolded text for useful info.)
I was on the fence about this. Atmos of course is first and foremost a new copy protection scheme that ties media listening to new hardware purchases with planned obsolescence baked in. Something I’m very much against and do not wish to precipitate in! Dolby is going very hard with refusing to license their decoder codec to any software media player outside their AC-4 reference player. They currently refuse to sell to anyone not a corporate partner and they consider this a courtesy download for their approved customers who purchase a $400/year subscription to their media encoder software. (It’s sold as a stand alone software product. It’s tied to the encoder subscription. Although it is a stand alone app that will run indefinitely.)
A very distant second is adding 4 channels to the 7.1 surround sound format for audio nerds like us. This is solely where my interest lies. What could be better than 6 channels for audio mixes? Well, 12 channels of course! Hanging 4 from the ceiling? Alright, let’s go!
For actual 7.1.4 audio mixes, one will need an array of the same speakers well calibrated. That means extending an existing array or starting over. I don’t have enough arms, legs, or kidneys to afford to expand the Genelecs. I didn’t think I would just stumble across more old AR9 speakers to let me expand more frugally… but I did!
The good:
More AR9 speakers is always a good thing!
Ability to finally hear the handful of 7.1.4 mixes coming out.
The bad:
Dolby encoded releases.
Dolby themselves.
Faux Atmos mixes that are mostly stereo. (Or worse, literally upmixed from stereo!) This stuff feels insulting after putting effort into setting up a system.
I think there’s some craftiness in the encoded format that could lead to single inventory. Not to confuse with gaslighting people into thinking they’re listening to surround with a binaural fold down to stereo earbuds or mutilated audio from a soundbar. But if the folddown works well enough for stereo devices or smaller speaker arrays it really could make for a crafty single inventory solution. At least in theory! The other direction scaling up to large theater installs is welcome of course.
I originally intended to play along by the book with Dolby software and releasing in the format down the road. Maybe it was the forum posts popping up explaining how to purchase the encoder subscription once to get their reference player that tipped them off but they only sell to “approved customers” now. If you don’t work for a company they already work with (Spoiler: That ain’t me!), they refuse to sell to you. They want listening ability tied to new hardware purchases and they’re playing hard. Because of this experience I’ll be releasing in standard wavpack file format once I get rolling with some mixes for my studio clients. I’m hopeful this idea takes over more.
The starting point for me had to be a real speaker array for lossless 7.1.4 mixes.
Then the ability to decode Dolby TrueHD+Atmos to 7.1.4 audio for access to encoded commercial mixes.
Next will be following up with decoding the lossy streaming version of the format. (Even if it’s mostly faux mixes at present.)
I also intend to run through encoding a 7.1.4 mix to their encoded format, followed by decoding it and nulling against the master. Diatribe to follow!
Note: It looks like their Atmos renderer app ($300) will create their master Atmos file set and also do an encode from that. This app IS available for sale to the general public! Note that the encoder app by itself will NOT encode a straight 7.1.4 audio mix! You need to buy the encoder app to get the reference player and then the renderer to put the 12 ch audio file to an intermediate format that the encoder can use. More details to follow as I learn them.
Some pics!
Looks the same...
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But look up!
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And around.
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Some technical details to save trail and error and stumbling through misinformation posted in some forums.
Before we even get into decoding the Dolby encoded versions of commercial mixes, a few things about MacOS and how to work around the disabling of controls. MacOS added the “Atmos” speaker array options to select in Audio MIDI Setup (the OS sound control utility) in Catalina 10.15.
Aside: I still recommend skipping Catalina (10.15) and Big Sur (MacOS 11). Catalina 10.15.7 thru Big Sur 11.6 have the brick bug. Your logic board can be bricked and you need a clip-on chip programmer setup to get back. Not worth the risk! Upgrade from Mojave 10.14 straight to Monterey (MacOS 12) if you value your time.
Apple’s Music app can decode and play the lossy streaming version of Atmos and only the lossy streaming version. It can not play lossless files from bluray! They also require a paid subscription to the streaming service to unlock the preference control in their Music app to enable Atmos playback. The Atmos setting in Music app preferences will be blanked out if you don’t have a subscription. Since this is only a lossy stream player at best anyway, I didn’t pursue this any farther.
When you set the system audio in Audio MIDI Setup to one of the Atmos formats (eg. 7.1.4), the Atmos channels (eg. ch 9-12 in 7.1.4) are muted/disabled from playback! I’m not sure if this is unlocked for other media player apps with a paid subscription to their Music streaming service. The channels are muted even when using a standard music player like VOX.app with your own files.
There’s an easy workaround!
When you select a device for system audio… DO NOT click on ‘configure speakers’ and select a speaker array format! Just don’t ever do it. (You will be scolded by various apps like VLC player that you haven’t selected an output format. Don’t do it! Just close that alert. It doesn’t stop playback.) Now all 12 channels (for 7.1.4 format) or 16 channels (for 9.1.6) just pass through and play!
There’s more good news. Not only that but you can play 12 or 16 channel 7.1.4 or 9.1.6 media in older MacOS like High Sierra (10.13) with the same method! The older OS doesn’t have the options to even select the Atmos speaker arrays, of course. Skipping the speaker config allows full playback just like in Monterey or Ventura. You can simply delete the device and start over if you have selected a speaker option previously. (Probably a preference file can be deleted to erase that selection too.)
And that’s it. Full unrestricted Atmos playback with 12 or 16 channel mixes going back to at least High Sierra. (Likely even older but I haven’t tested it.) You get the expected channel order. L R C Lfe Lss Rss Lrs Rrs Ltf Rtf Ltr Rtr for 7.1.4, for example.
The only con to this is no longer being able to have the system speaker manage higher channel formats into smaller speaker arrays or mix and match formats in a media player playlist that supports that (like Songbird did with 4.0 vs 4.1 vs 5.0 vs 5.1). But we’re here for Atmos! Make an alternate output device to select if you need to keep older features like that around for everything else.
I’ve tested this with VOX.app in High Sierra, Monterey, and Ventura with standard 12 ch audio files in wavpack format.
(Sorry I don’t know Windows at all and I haven’t jumped ship to Linux quite yet either. Not sure what is or isn’t possible there.)
Decoding Dolby encoded Atmos.
To the best of my knowledge, Dolby’s reference player is the one and only media player app that will decode and play Atmos encoded files. They really have the lockdown on this. It’s technically a courtesy download when you purchase a subscription for their media encoder and not for sale stand alone. It is a stand alone app that will continue to function if you let that subscription expire. They are currently refusing sales to anyone they aren’t affiliated with. (I can’t and will not help with this, sorry!)
You need Dolby’s reference player to play encoded files and that’s a hard bottom line at present.
Ripping from bluray and extracting and converting the files to the correct format.
MakeMKV will rip the Dolby TrueHD+Atmos file from disc to .mkv file.
MKV Extract will extract the TrueHD+Atmos content to .thd files. (TrueHD file format)
I found a GUI build called Inviska MKV Extract. No command line apps required!
Finally, change the file extension on those files from .thd to .mlp. <- Seriously really truly! Yep, that was their security here.
The reference player will now simply play the .mlp files. And we’re done!
Note: There are forum posts describing first splitting the .mkv (or .mka if you did that instead) into separate songs using MKVToolNix app. Then extracting those and changing the extension as described. The split files fail to play and crash the reference player about half the time. There’s something going on like a key frame situation for video that happens here. I don’t know how to work around it yet.
My plan for now is to record the 12 channel output into a DAW and manually split and save as wavpack files to keep in my music archive. (Just like we do with flac for disc based media. Wavpack instead of flac now because flak only supports up to 8 channels.) Because keeping files in a proprietary encoded format can lead to losing playback ability with some future update. (Which is sometimes done intentionally.)
Again, VOX.app media player just works. And of course, standard unencoded 12 ch files just work to begin with.
My “home theater” setup is to use a virtual audio device as main system output device. Currently using Loopback app for that. I do some speaker management with a DAW app for my system needs. System sound to a Loopback 16 channel pass thru device. I make an aggregate device of the Loopback device + my audio interface for the DAW based speaker management. I use a “high tops” array that needs sub bass redirected to the sub channel as many people do. Work your system like you normally do.
Happy listening!
Discoveries and conspiracies, oh my!
The Dolby reference player will play the full 12 or 16 channels into the output device even with the 7.1.4 or 9.1.6 speaker configuration selected in Audio MIDI Setup! Dolby is allowed past the gatekeeper.
The reference player uses a script based installer package. I don’t see any of the expected library application support files in the usual spots for this kind of install. Dropping just the app file (if you first installed this on one of your other computers) will still not work - like one would expect from a more complex install. The only associated file I found in the User account library/Application Support folder is a running log of every track you play in the reference player. (Seriously Dolby?!) The app has not ever tried to call home though. One might speculate that the installer script uses your logic board ID to lock the app to your system. One might speculate that Dolby just might release this reference player installer with some unique ID for every customer/partner who downloads it. Careful out there and mind your software user agreements!
"What, you don't have 200 channels in your listening room?? Your such a Luddite!"?
There is no end to this as surgeons will figure out how to 3D print more ears and graft them on somewhere! So then we will hear, "My left ass cheek channel went out, anyone know why?"
