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AAC/AC3 vs Dolby Atmos/DTS-HDMA

Blumlein 88

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Atmos does not have ‘bed’ channels. It’s completely object based and the 5.1 and 7.1 mixes that are included by default are simply for backward compatibility and serve no purpose at all once there is an Atmos renderer in the playback chain.
Dolby disagrees with you.

Mixing and recording Bed and Object audio along with OAMD is how Dolby Atmos content is created.

The Dolby Atmos Renderer captures up to 128 tracks of audio. The first 10 tracks are dedicated to capture Bed audio with a width up to 7.1.2, and the remaining 118 inputs can be used for Objects and/or additional Beds. Additional Beds may be used to facilitate multiple DAW systems working on different stems (i.e., Dialog, Music, Effects), and to simplify workflows to derive channel-based stems. Increasing the number of Beds reduces the number of tracks available for Object audio. More on this later.

The OP and I are considering the differences when you don't have Atmos rendering available.

I hope in the near future to add Atmos to my HT setup, but don't have it currently which is why I've noticed the same things as the OP.
 

Sancus

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The Dolby Atmos Renderer captures up to 128 tracks of audio. The first 10 tracks are dedicated to capture Bed audio with a width up to 7.1.2, and the remaining 118 inputs can be used for Objects and/or additional Beds. Additional Beds may be used to facilitate multiple DAW systems working on different stems (i.e., Dialog, Music, Effects), and to simplify workflows to derive channel-based stems. Increasing the number of Beds reduces the number of tracks available for Object audio. More on this later.
This is cinema Atmos, not HT Atmos, they're totally different.

HT Atmos is *usually* LFE + up to 16 objects. This is easy to see if you have any bluray rips and use mediainfo, it will tell you how many objects/beds are in Atmos. The difference is mostly that objects can be panned in 3d space freely whereas beds can't be.

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Part of the confusion here is there are a bunch of different Atmos standards and a lot of how they are used is up to the mixer, not a requirement. Apparently there might be a reason to use bed tracks for bandwidth-limited streaming Atmos due to how the different parts are encoded. I hadn't heard that one before. There seems to be disagreement about the best approach even among people who work in that industry.

So, Atmos can be a combination of objects or beds and it really depends on what specific mix and type of Atmos you're talking about.
 

kongwee

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You *can* use the bed channels in the Atmos mix but it's almost never done as I understand it. The only bed used is the LFE. Instead objects are used, and sometimes those objects mimic bed channels, but actual beds are not typically used. The embedded TrueHD(or DD+ for streaming) 7.1/5.1 tracks for backwards compatibility are separate.
For music, I don't get the need to use bed for bass. Basically you can lay out your drum set, guitar, bass, vocal exactly you want in GUI. Vocal infront of drum set without adding any effect. Atmos already have that space created for you. Then add your lexicon reverb plugin to process the environment you want. It is totally a different mix from bed channels.
 

Blumlein 88

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This is cinema Atmos, not HT Atmos, they're totally different.

HT Atmos is *usually* LFE + up to 16 objects. This is easy to see if you have any bluray rips and use mediainfo, it will tell you how many objects/beds are in Atmos. The difference is mostly that objects can be panned in 3d space freely whereas beds can't be.

index.php


Part of the confusion here is there are a bunch of different Atmos standards and a lot of how they are used is up to the mixer, not a requirement. Apparently there might be a reason to use bed tracks for bandwidth-limited streaming Atmos due to how the different parts are encoded. I hadn't heard that one before. There seems to be disagreement about the best approach even among people who work in that industry.

So, Atmos can be a combination of objects or beds and it really depends on what specific mix and type of Atmos you're talking about.
Didn't realize there was the split in Cinema and HT.
 

Offler

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This is cinema Atmos, not HT Atmos, they're totally different.

So, Atmos can be a combination of objects or beds and it really depends on what specific mix and type of Atmos you're talking about.
I would be very careful when using term "standard" in regard to Atmos.. its more like a brand. And as you mentioned it, there are different ways how to apply it.​
HDR "standards" are "not" followed in similar way. You can have content with light level up to 10 000 cd/m2, but most commercially avalable TVs or displays with that brand are not capable of that. I really wonder how is such content mastered anyway, if commonly available displays are 400-600cd/m2.​
 
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