Dolby surround 7.1 clarification

[vudoo]

I wonder why Dolby call 7.1 surround ''Dolby surround 7.1'' ?

All Digital Cinema Projection (DCP) can output up to 12 channels @ 24 bits/96 Khz as per DCI specifications. No encoding/decoding/matrixing is required. This means the ability to produce 7.1 channels of sound is built into every Digital Cinema Projection system and nothing about it is unique to Dolby technology or equipment. So is Dolby surround 7.1 simply a marketing term used by Dolby ???

[tom_lowe]

Originally Posted by vudoo

I wonder why Dolby call 7.1 surround ''Dolby surround 7.1'' ?

All Digital Cinema Projection (DCP) can output up to 12 channels @ 24 bits/96 Khz as per DCI specifications. No encoding/decoding/matrixing is required. This means the ability to produce 7.1 channels of sound is built into every Digital Cinema Projection system and nothing about it is unique to Dolby technology or equipment. So is Dolby surround 7.1 simply a marketing term used by Dolby ???

Yes, because most cinemas use Dolby processors that are capable of 7.1 and the audio from the DCP goes through them.

http://www.dolby.com/gb/en/professio...round-7-1.html.

[Alexander K]

They call it that way to differentiate their sound format from the other 7.1 format.
Basically DCP is capable of delivering two 7.1 sound formats: The one specified by DCI has the channel layout of the old SDDS 7.1 format.
The Dolby 7.1 format isn't specified within DCI, and so it is not mandatory to the projector industry to test their sound outputs with this format nor providing output capability with their devices. The only D-Cinema projector/server company who definitely will provide support for this format is Dolby.

[vudoo]

Originally Posted by Alexander K

They call it that way to differentiate their sound format from the other 7.1 format.
Basically DCP is capable of delivering two 7.1 sound formats: The one specified by DCI has the channel layout of the old SDDS 7.1 format.
The Dolby 7.1 format isn't specified within DCI, and so it is not mandatory to the projector industry to test their sound outputs with this format nor providing output capability with their devices. The only D-Cinema projector/server company who definitely will provide support for this format is Dolby.

When you mention the DCI vs Dolby format, do you simply mean the different channel order (lay out) ?

[Alexander K]

Yes. There is no other difference between those two 7.1 formats within the DCP file.

[vudoo]

thx guys

[jeremiahmoore]

Request for further clarification:

From what I'm reading here, the DCP standard for 7.1 then specifies the SDDS layout of 5 across the front, and two surround speakers. *not* the Dolby spec of adding rear surrounds. Is this correct?

I'm mixing 5.1 for DCP with some regularity here. (i.e. we do a 5.1 mix, and a film festival or other exhibitor will screen via DCP.) Generally we avoid Dolby, unless the film is a Dolby mix.

No requests as of yet for 7.1 But if there was such request, it will be critical to know the speaker layout expected.

-jeremiah

[vudoo]

Originally Posted by jeremiahmoore

Request for further clarification:

From what I'm reading here, the DCP standard for 7.1 then specifies the SDDS layout of 5 across the front, and two surround speakers. *not* the Dolby spec of adding rear surrounds. Is this correct?

I'm mixing 5.1 for DCP with some regularity here. (i.e. we do a 5.1 mix, and a film festival or other exhibitor will screen via DCP.) Generally we avoid Dolby, unless the film is a Dolby mix.

No requests as of yet for 7.1 But if there was such request, it will be critical to know the speaker layout expected.

-jeremiah

As a mixer, your only concern is to label your files properly. The track ordering will be taken care at the DCP authoring stage. I believe you're right about the SDDS lay out. I will check on the Christie IMB and let you know.

[jeremiahmoore]

Thanks vudoo.

My concern is primarily to inform my clients, so they can make the best possible choices.

-jeremiah

[Alexander K]

If your clients demand for a Dolby Surround 7.1 mix then follow the Dolby guidelines or contact your local Dolby consultant for help.
There is more to it than just speaker placement.
You have to create a 5.1 downmix as well.

What happens after the mix is up to the person / studio who is responsible for distribution of the production. If i.e. a movie is released in DS7.1 then the DCP authoring studio will take care of the appropriate channel mapping within the DCP and proper labeling of the drives.
If somebody is authoring the DCP by oneself, then he or she will notice that DCP tools like easyDCP Creator doesn't provide a channel mapping for DS7.1 but for (SDDS)7.1 because of DCI. You have to use a custom setup and follow the Dolby guidelines. These documents contain the channel mapping (needed channel numbers for each of the eight channels).
It could be necessary to provide the 5.1 version as well, for 5.1 theaters. If you or your clients really handle this by your own, then talk to the cinema management to make sure you provide them with the right soundtrack (or both of them).