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1) Do you have a good source that could recap it so that would help others if they want to read up on this in the future?
Dolby Developer website is the only place to research it all. Dolby Atmos is split into Home Theatre, Cinema, Mobile, Headphones, Gaming, etc. And then it goes into detail on the codecs, bitrate, bandwidth, connections, devices, and more. There isn't a recap or one page other than what I have written that can do it.
Ah a pity, but thanks 🙂
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2) I've read up over the years quite a bit about LPCM vs Bitstream and it helped me make the guides I have linked to others in the past. I have known for some time what Atomos was and how it only contained Dolby Digital Plus (E-AC-3 JOC) or Dolby TrueHD (MLP FBA 16-ch) and how that allows systems like Bose's current and older Lifestyle systems to work with Atmos soundtracks.
What I was unsure about is if LPCM 7.1 would be able to send that Atmos signal or not. From what you said, even forcing LPCM 5.1 and using one of the unused channels for the Atmos positioning data still would not work.
So, Linear PCM is just analogue audio but is carried over a digital cable which results in cleaner audio. Because it's not wrapped or compressed, there isn't anywhere to add extra data. The way it works is each channel individually sends the audio down the cable to the receiver rather than wrapping all of the channels together and sending them in packets similar to Dolby Digital or TrueHD. Only way to get Linear PCM audio with Dolby Atmos is to wrap it in Dolby MAT.
Yeah, luckily I do what LPCM is, though the question with me was how LPCM would treat Atmos content. What you stated in this thread is what I thought would happen. Though I had hoped that there was a workaround within existing tech (not just Dolby MAT which is new tech). It's a pity, though not too unexpected.
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3) I think I missed something here, what is Apple getting around?
Apple is able to use Dolby MAT because they're able to force the hand of the applications to support it. However, they do still support Dolby Digital Plus for outputting, they just prefer to use Dolby MAT and Linear PCM if the receiver support it.
Yep, with the Soundbar 900:
- LPCM 7.1 will be the only way to be able to play Dolby Digital Plus
- Dolby MAT would be the only way to get Atmos Dolby Digital Plus
But you can still get standard Dolby Digital 5.1 if you send it a bitstreamed version.
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4) Is it not a good thing that Apple does this as Soundbars such as the 900 would work not caring what 3D audio positioning format it was originally encoded in?
Apple TV can still output Dolby Digital Plus with Atmos similar to how it can output Dolby Digital because the streaming audio is pre-encoded. It's just preferred that if your soundbar supports Linear PCM or Dolby MAT, it will output everything analogue that way. It's definitely much better, especially for the Bose Soundbar 900 as if it truly won't support Dolby Digital Plus, it would be one of the only ways of gaining Atmos from streaming services.
So yes that is a good thing, but the issue is that not everyone does this 😕
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But technically, even though the audio is Linear PCM, it still came from a lossy audio format. It won't improve the audio unless you're using an application such as a game that directly outputs the Linear PCM audio.
Yep, I know. I mention that in a few places. Even Dolby themselves called Dolby Digital Plus "Enhanced" (E-AC3) compared to the lossless Dolby TrueHD.
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5) So the question is this. Can all source devices that support Atmos & LPCM also support Dolby MAT with a firmware update or is it a hardware issue? What about DTS:X? Would that be converted into Dolby MAT?
As long as it has suitable hardware and power, there is no limitation other than licensing I suppose.
Ah, I feared that. LPCM was great as it didn't have any licencing fees attached to it. When I saw the name "Dolby" it did make me concerned that would not be the case here. I do suppose that makes sense though as you need to decode Atmos before you can reencode it into LPCM Atmos.
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The Apple TV 4K specifically has a Dolby MAT encoder and the Xbox One removed a lot of the Kinect dashboard integration which allowed them to enable Dolby Atmos on the console with Dolby Atmos for Headphones and Dolby MAT by using the secondary processor.
The Xbox Series X|S actually have an audio processor which was built specifically to drive 3D audio for Dolby Atmos to allow it to output much cleaner than the Xbox One.
Ah, I assumed it was done via software. Atmos, while been out for a few years now, is still relatively new. Well decoding it via a dedicated chip will make the reencoding faster, but it will add to the cost of manufacturing. So I can only guess this won't be a popular as I had hoped. That is unless there is a popular chip for other manufactures out there that also decodes Dolby TrueHD and the such.
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Dolby MAT is just Linear PCM with Atmos metadata. But it's an extra licence they have to pay and with most streaming services already having the entire thing compressed as Dolby Digital Plus, there isn't much point. One licence for Dolby Digital Live and you've covered both 5.1, 7.1, and Atmos. (..)
But I believe that Dolby MAT can actually rip apart a Dolby TrueHD file and split it back into Linear PCM and Atmos. The only reason is that TrueHD is technically lossless audio. However, as the Bose Soundbar 900 already supports TrueHD, there isn't much point other than the source device deciding whether it wants to do that or not.
Darn (I first said dam...n but it got censored... I wouldn't have thought of that as a bad word 🤷♂️), I was hoping that Dolby MAT was covered in the standard Atmos licencing fee, not requiring a separate one.
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It won't touch DTS, but at the same time, it needs to know that it's doing Dolby MAT. As far as I know, there has to be support from both the device and the application.
Is there a DTS:X alternative to Dolby MAT or will the Soundbar 900 only ever support DTS via standard LPCM without 3D audio (Object-Based) encoding?
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6) Yes, that I have known for a while now and I find it very helpful. Though I do wish that instead of saying it is Atmos I wish it would let you know if it is the lossy or lossless version of Dolby in the file.
If it's is coming from a streaming service, it's going to be lossy. If it is coming from a Blu-Ray, it's near enough lossless even with Dolby TrueHD. If it is coming from a game such as a PC, it's pure Linear PCM lossless.
Yeah though (unless I am remembering incorrectly) I believe have encountered at least one Blu-ray/UHD which uses Atmos Dolby Digital Plus. I personally would like to have a way to distinguish the lossy core from the lossless one.
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7) It looks like there is a solution to using LPCM with Atmos in the form of Dolby MAT. So the question has to be if this is going to be the future of audio devices or a niche audio codec.
It's not niche, but it's another option that is available. It's not going to supersede another format such as TrueHD as we still need to compress down audio to fit onto media. You will see it more for live audio such as gaming as if the game is throwing out a Linear PCM audio signal, you might as well add the 3D metadata and call it a day because HDMI has enough bandwidth. No point in creating another encoder to force it into a TrueHD format. Just adds latency and can cause other issues. Dolby MAT was basically designed not to encode, but just to box up the two for shipping.
No, I wasn't thinking about it superseding anything. I was hoping that Dolby MAT (or something like it) would become the norm. Though as it requires another licencing fee and the possibility of increasing the costs of the hardware, it does not look like this will be the case.
The great thing about LPCM 7.1 is that it was royalty-free and was a minimum requirement for Blu-rays and HD-DVD's when they first came out and through to today.
Receivers that supported LPCM 7.1 allowed it to play formats it didn't support and possibly new audio formats that might come out years after that receiver was first sold. I was hoping that if LPCM 7.1 couldn't support the Object-based information that there would be a royalty-free alternative that would be required to continue that trend. It seems that is not the case.
