Dolby Atmos / 7.1 combo

[Erik Olsen]

Hi.
Sorry if this has been asked before, I tried to search but could not find anything about Atmos / 7.1 combo file.

I have 7.1 installed in my theater so my question is:
The movie "A quiet place 2" and "Fast & furious 9" comes in two different versions. One with 5.1 sound and one Atmos/7.1 combo file.
Will the Atmos / 7.1 combo file play the 7.1 sound on my NON Atmos receiver?
I can not try my self since I have only been sent the 5.1 versions of the movies.

Regards.
Erik

[Carsten Kurz]

Hi.

Will the Atmos / 7.1 combo file play the 7.1 sound on my NON Atmos receiver?

Receiver? What type of 'receiver'?

Usually, ATMOS features play in plain 5.1 or 7.1 on non-ATMOS enabled systems. It is the DCP server, though, that is responsible.

[Erik Olsen]

OK, so receiver was not the right word. Non-atmos processor then?

We play the files on DoReMi DCP 2K4 and use Yamaha DME64 for the sound.

So I asked the movie distributor if I could have the ATMOS / 7.1 combo DCP so that I could show the movies in 7.1.
But the very short one line answer from them was "Dolby ATMOS is for theaters with AMTOS only"
But I am pretty sure that I have had DCP's that have stated 5.1 / atmos in the filename before. So to be sure I wanted to ask the experts here that actually show the movies in theaters.
It is kind of sad if they have a 7.1 version, but that is only available to theaters with ATMOS. Especially as they only need the 7.1 to fall back to if the ATMOS failes.

Regards,
Erik Olsen

[Leo Enticknap]

All the Atmos DCPs I've ever handled have also had a conventional 5.1 or 7.1 track, that will play on a non-Atmos system (or if you check the "Ignore Atmos" box on the CP850's web UI). On systems that require a separate KDM for the Atmos media block, e.g. Barco ICMP, that track will also play if you have the KDM for the regular DCP, but not the additional Atmos KDM.

On such a DCP, the audio tag will typically read something like 51-HI-VI-ATMOS, or 71-HI-VI-IAB. IAB (Immersive Audio Bitstream) is the new ISDCF tag for all immersive audio streams, which they are trying to encourage the use of, rather than any proprietary names, e.g. Atmos or Auro. Whether you see 51 or 71 at the start of the tag indicates the non-Atmos format that will play if you have a non-Atmos system, or don't have the Atmos KDM.

[Erik Olsen]

Thanks so much for the replies.
I thought that would be the case, since they even call it a combo file.
I have received KDM for both the 5.1 and 7.1 combo. The file says "xxxxxxxx-71-Atmos-Dbox_2Kxxxxxxxx", so I will ask the distributor again to send me the Atmos combo file.

Regards,
Erik

[Marcel Birgelen]

How did you get the DCP? Via hard-drive or via on-line distribution? For disk-based distribution, they usually package all the different versions onto the disk.

[Marco Giustini]

as stated above, Atmos is a separate thing and the PCM track - whether 5.1 or 7.1 - is always going to be available on ANY DCP.

You may get a plain 5.1, a plain 7.1, an Atmos-5.1 or Atmos-7.1. They will ALL play in non-atmos auditoriums.

"Atmos-7.1" means "I've got the Atmos track AND the 7.1 PCM track which is used either if Atmos fails to work or if Atmos processor is not available".

[Steve Guttag]

For what its worth, A Quiet Place II has a non-Atmos 7.1 version, that I've seen. And yes, the Atmos version will play in non-Atmos houses without Atmos. They key (literally) is getting the key from the distributor that allows you to play a 7.1 version, if it is part of the Atmos version.

[Leo Enticknap]

Amen to that. I recently upgraded two houses in a 'plex from a CP750 to a 950, and from 5.1 to 7.1 in the process (because HI and VI were going through the 750, and so it couldn't process 7.1 audio). There were separate power amp channels and wiring to the rear surrounds, but they had never been used split from the sides.

I briefed the managers that they needed to request KDMs for 7.1 versions going forward, and ingest the 7.1 VFs from Deluxe drives. But when I was back there to do something else a few days later, I saw that they were still playing 5.1 DCPs in those two screens, of titles that I knew had 7.1 versions available.

[Frank Cox]

There's something else that I don't understand. Why is 5.1 and 7.1 sound even a separate thing in terms of keys and such? Why would it matter to the film companies if you're playing 5.1 or 7.1?

[Carsten Kurz]

They contain different audio assets. So they need separate CPLs. So they need different KDMs.

There is a concept in SMPTE DCPs that would allow to have both 5.1 and 7.1 in a single CPL, using variable audio routing. However, it is not used because, given the current equipment capabilities, it would result in a mess with audio coming out of the wrong channels (incl. HI and VI-N) in many installations. The idea was nice, but it's simply not ready for prime time.

In theory, using SMPTE capabilities, one could have a single DCP/CPL containing 5.1, 7.1 HI/VI-N, ATMOS and dbox. Even including the 'old' Auro-3D. No one was keen enough to try it, and I guess for good reasons.

[Harold Hallikainen]

It has been suggested that the "backup" main sound be silent in IAB DCPs with only HI and VI audio being present. I have heard a concern that people think they are playing ATMOS when they are actually playing 5.1 or 7.1. How often does rendering fail and mainsound ends up being used?

Harold

[Leo Enticknap]

The problem with no backup main sound on an IAB CPL is exactly the same as that with 70mm DTS: if the Atmos does fail, you're buggered. My guess is that Atmos rendering only fails if the end user doesn't have an Atmos KDM, but as CP850s get older and cat1600 batteries begin to go bad, that might start to be a reason, too.

Why is 5.1 and 7.1 sound even a separate thing in terms of keys and such? Why would it matter to the film companies if you're playing 5.1 or 7.1?

Because studios sometimes charge exhibitors more for the 7.1 mix, especially for prestige blockbusters.

[Carsten Kurz]

For a while, the Barco ICMP had big problems losing connection to CP850. Given the complexity of external realtime audio renderers, a working backup main sound seems absolutely necessary to me.

[Marco Giustini]

What Carsten said. When it works, Atmos works. But there may be a day when the MB somehow fails to secure an encrypted link and then your Atmos won't work. A backup is a necessity indeed.