Film-Tech Forum ARCHIVE: 7.1SDS Content?

This is topic 7.1SDS Content? in forum Digital Cinema Forum at Film-Tech Forum ARCHIVE.

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Posted by Harold Hallikainen (Member # 5405) on 11-03-2014, 11:42 AM:

SMPTE 428-12-2013 provides a standard soundfield group list. These are 5.1, 7.1DS (rear surrounds), 7.1SDS (no rear surrounds, but Lc/Rc), 6.1 (includes center surround), and 1.0 (mono through center speaker).

Is any content currently shipping with 7.1SDS?

Thanks!

Harold

Posted by Steve Guttag (Member # 268) on 11-03-2014, 01:05 PM:

None that I've found but I'm definitely looking. I've been very disappointed with 5.1 mixdowns of what should be 7.1SDS tracks (Todd AO). For instance, the Oklahoma! DCP should have been a 7.1SDS but was issued in 5.1.

Posted by Dave Macaulay (Member # 813) on 11-03-2014, 07:35 PM:

Agreed that 5.1 reissues of 70mm features that should have 5 screen channels leaves two big holes in the soundfield.
How big a market is there? Are there many screens with the Le and Re channels - and wide enough to really show them off? Producing a VF for this wouldn't be cheap, but (I think) less effort and cost than remixing to 5.1.

Posted by Marcel Birgelen (Member # 6801) on 11-04-2014, 02:59 AM:

The lack of 7.1 SDS mixes probably even didn't motivate many of those SDDS converted houses with 5 stage channels to keep those speakers wired.

It's disappointing that even Dolby Atmos designates those two extra front speakers as optional. What use is it to have the best possible accuracy everywhere but there were it matters most?

Auro3D does add three extra stage channels, but they're height channels, so no use either...

Posted by Steve Guttag (Member # 268) on 11-04-2014, 06:27 AM:

I would think to have a VF file for 7.1SDS would actually be relatively cheap because it is already mixed that way...the cost would have been in creating the 5.1...which they would need to do for the valuable video release for the home.

There are a fair number of a 5-screen channel theatres out there still. And those that are likely to play classic 70mm titles are going to raise those odds a bit.

Posted by Marco Giustini (Member # 4544) on 11-04-2014, 10:38 AM:

Steve,

are those theatre ready to play 7.1SDS content or would they need to upgrade/rewire?

Posted by Steve Guttag (Member # 268) on 11-04-2014, 11:02 AM:

I can't speak to all of them...I can only speak to the ones we directly have contact with and the answer is YES! If the theatre had 5-screen channels before, they still do now and we ensured that those would be supported going forward. For instance, the AFI/Silver has two screens with 5-screen channels (one was to support SDDS-8 as well as narrower aspect ratios so that Left and Right were not beyond the image). Both of those theatres fully support 7.1SDS without any rewire or effort. It is just a preset for them.

The format that has taken some off guard is actually this 2.0 Lt/Rt business. Almost no processors support it out of the box. The CP750 being a notable exception. Yes, you can "create" something with one or two of the others but it is typically a lame L+R, L-R sort of "decode" rather than a proper pro-logic type steered sound.

Posted by Daniel Schulz (Member # 1881) on 11-04-2014, 11:17 AM:

I wish I had a time machine, so we could have set the D-Cinema standard to be 9.1 (5 screen channels + 4 surrounds), with a requirement that the server be able to downmix to 7.1 or 5.1. There there could have still been a single DCP inventory, with confidence that the soundtrack would play back appropriately.

Posted by Ian Freer (Member # 1940) on 11-05-2014, 09:55 AM:

The Datasat AP20 supports 2.0 LtRt matrix decoding out of the box too I believe.