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Author Topic: Imax digital DCPs
George Murray
Film Handler

Posts: 23
From: grand forks ND,
Registered: Jun 2012


 - posted 10-01-2013 09:28 AM      Profile for George Murray   Email George Murray   Send New Private Message       Edit/Delete Post 
Does anyone know the difference between imax dcps and regular dcps. How much bigger or smaller are the movie files and does the dmr actually do anything? and what about the sound mix is there a difference there as well?

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Edward Havens
Jedi Master Film Handler

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From: Berkeley, CA
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 - posted 10-01-2013 03:29 PM      Profile for Edward Havens   Email Edward Havens   Send New Private Message       Edit/Delete Post 
Doing a Google search for "IMAX DCP" brought me to this IMAX blog post from last year explaining the difference.

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Marcel Birgelen
Film God

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From: Maastricht, Limburg, Netherlands
Registered: Feb 2012


 - posted 10-01-2013 06:55 PM      Profile for Marcel Birgelen   Email Marcel Birgelen   Send New Private Message       Edit/Delete Post 
This has been discussed here before, but that link to the IMAX page you published is, unfortunately, largely just IMAX marketing bs.

IMAX DMR is supposed to be a way of processing 35mm movies and reducing film grain by scanning them at ultra-high resolutions and use the "otherwise invisible stuff between the grains" as means of recovering this "hidden resolution". Also, it seems to employ some noise reduction algorithms that reduce film grain, probably at the cost of sharpness.

While this might still be true for stuff that was actually acquired on 35mm and was never transferred from some rather low resolution digital intermediate, this would be total bullshit for any digital production...

Still, DMR could mean something entirely different for digital content, but IMAX is not telling us what that could be. But, maybe they just run the same bunch of algorithms on digital content, you never know, there might be some hidden information left between those pixels [Razz] .

So, are IMAX DCPs different from normal DCPs? Yes, they are, they require different keys to begin with. How do they differ? That's something only IMAX knows for sure and they will probably not tell us, because that's part of their secret sauce(tm).

Why do we know for sure at least some of them are different?

1) IMAX DCPs are sometimes in a different aspect ratio. The normal DCP release might be scope, whereas the D-IMAX version might be 1.77:1.
2) Some productions like The Dark Knight Rises, switch between aspect ratios in their D-IMAX version, but don't do that in the scope DCP.
3) Their sound setup is different from your normal 5.1 or 7.1 setup and I suspect their actual sound mix in the DCP is also different.

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Terry Lynn-Stevens
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From: Toronto, Ontario, Canada
Registered: Dec 2012


 - posted 12-04-2013 09:44 PM      Profile for Terry Lynn-Stevens   Email Terry Lynn-Stevens   Send New Private Message       Edit/Delete Post 
quote: Marcel Birgelen
IMAX DMR is supposed to be a way of processing 35mm movies and reducing film grain by scanning them at ultra-high resolutions
IMAX does not scan the 35mm images, they are delivered in a digital form.

quote: George Murray
does the dmr actually do anything? and what about the sound mix is there a difference there as well?
Both the images and sound mix are modified. Whether or not there is a benefit to these enhancements is open to viewer interpretation.

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Steve Kraus
Film God

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From: Chicago, IL, USA
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 - posted 12-04-2013 10:47 PM      Profile for Steve Kraus     Send New Private Message       Edit/Delete Post 
What server do they use?

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Gordon McLeod
Film God

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From: Toronto Ontario Canada
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 - posted 12-04-2013 10:52 PM      Profile for Gordon McLeod   Email Gordon McLeod   Send New Private Message       Edit/Delete Post 
imax does scan dkp70mmm inc has a very precise film scanner

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Terry Lynn-Stevens
Phenomenal Film Handler

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From: Toronto, Ontario, Canada
Registered: Dec 2012


 - posted 12-05-2013 07:39 AM      Profile for Terry Lynn-Stevens   Email Terry Lynn-Stevens   Send New Private Message       Edit/Delete Post 
I guess that would be the case. IMAX just announced that a third party company will be scanning their 70mm library for release in 4K.

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Dave Macaulay
Film God

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From: Toronto, Canada
Registered: Apr 2001


 - posted 12-11-2013 07:24 AM      Profile for Dave Macaulay   Email Dave Macaulay   Send New Private Message       Edit/Delete Post 
Imax uses Doremi servers with dual SDI output. Projectors were Christie 2220 and are now Barco 32B, all are 2K. The content itself may be the same as on regular drives, who knows? We won't be able to compare it digitally. The data flow after the server is quite different from normal single or dual projector systems though. There is no link encryption, I don't know whether the servers even have encryption cards. The image data goes through the "magic" box that alters each image so that the dual projector images align very closely. The entire outer monster housings are a secure enclosure because the image data is passed around on unencrypted dual SDI.
There are forum members who have a big hate on for Imax. Jealousy?
Imax digital is far from perfect, and a pale shadow of Imax 15/70 - true.
The daily Imax system "self calibration" keeps the image and sound quality reasonably decent: the chain "ultra" screens get typical attention where focus, brightness, sound setup, 3D adapter moves, etc are unpredictable.
Light level in 3D is better than 99% of non-Imax screens. The polarizers are automatically moved so no 2D feature shows through them ever. 3D images are not alternating, both are on screen simultaneously - other dual projector 3D systems do this but that's a fraction of one percent of non-Imax 3D screens.
It is not 4K, admitted. I expect they are working on that... redesigning the image processor is the likely holdup as it will be handling 4X the data. I'm not sure there has been a 4K 3D release anyway.
The huge advantage - here in Canada at least - is that an Imax screen jumps you ahead of any competition without Imax when booking content. An independent Imax digital cinema next door to a Cineplex with a "super ultra extra whizbang-o-vision 4K Atmos with vibrating recliners" premiere screen will be able to book all the blockbusters on opening night. Without Imax they could maybe open Oogieloves, the Cineplex would get every major release. No chain "premiere" system has that advantage.

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Terry Lynn-Stevens
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From: Toronto, Ontario, Canada
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 - posted 12-11-2013 09:09 AM      Profile for Terry Lynn-Stevens   Email Terry Lynn-Stevens   Send New Private Message       Edit/Delete Post 
Dave, thank you for some mature alternative commentary that is not the typical IMAX sucks and they are going out of business because they no longer use 15/70 stuff.

Most of what you wrote was pretty informative to me. The brightness levels are pretty good, much better than UltraAVX. Some of the images from Catching Fire looked outstanding for a 2K presentation, those images were from the anamorphic scenes, but then there were some images that did not look great. The IMAX sequences of the movie where a little underwhelming in digital I must admit.

I am assuming the current Christie projectors could be upgraded to 4K in the future? I also never knew that IMAX would get the preferred booking, but Cineplex owns almost all the IMAX theatres in Ontario so I guess it makes no difference.

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Steve Kraus
Film God

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From: Chicago, IL, USA
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 - posted 12-11-2013 11:54 AM      Profile for Steve Kraus     Send New Private Message       Edit/Delete Post 
I thought the more recent LIEMAX's were 4K but maybe that info was incorrect.

So are you saying the stuff that is done to the image data where the two projectors are getting slightly different data is being done on the fly there at the projector / server level and not back in Toronto? (On 2D. Presumably LIEMAX 3D is just ordinary two projector 3D like anyone can do if they want to spend the money.)

I think I speak for many when I say what we resent about LIEMAX is not LIEMAX itself which is an excellent presentation for 2K. I support the idea of premium theatres. I don't always think they are worth the upcharge but people can decide for themselves. You can only be fooled once. None of the other premiums that I am aware of even use two projectors. No, what I, and presumably others, resent is the unqualified use and dumbing down of the name IMAX. If they'd simply said IMAX DIGITAL there would not have been so much outcry.

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Bobby Henderson
"Ask me about Trajan."

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From: Lawton, OK, USA
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 - posted 12-11-2013 03:05 PM      Profile for Bobby Henderson   Email Bobby Henderson   Send New Private Message       Edit/Delete Post 
Dual projectors may not be found in every premium priced big screen theater, but I don't know how else one can show 3D at satisfactory brightness levels on a large screen without using dual projectors. It's really the only selling point IMAX possibly has over its big screen rivals when it comes to showing movies in 3D.

A single projector, such as a Barco DP4K-32B or Christie D4K3560, will throw a reasonably bright 2D image onto a giant sized screen. The same isn't true for 3D. I'm sure some premium priced theaters are probably trying it, but I don't think RealD or Dolby 3D will show an acceptably bright image on a giant screen from a single projector.

Some big screen theaters in my region, such as Harkins' Cine Capri screen at the Bricktown 16 theater in Oklahoma City or the two Grand Auditoriums at the Moore Warren Theater in Moore, OK only show movies in 2D. Warren had tried, briefly, showing movies in Dolby 3D in the Grand Auditoriums but quit that. None of those theaters charges a premium for entry, except for the adults-only balconies in Warren's Grand Auditoriums. The Cine Capri is equipped with Dolby Atmos but still charges a standard price.

If Regal has followed what they mentioned in their press releases when launching the RPX concept all of their RPX theaters should have a dual projector setup.

I don't know if any of AMC's ETX screens have dual projectors. Same goes for Cinemark XD, Carmike Big D, Santikos' AVX Max, etc.

Christie sells a "duo" package that works with most of their cinema grade digital projectors. I don't think they would have such a kit, including alignment software, if they didn't have a good supply of customers.

(Edit)

Maybe someone or numerous participants at Film-Tech should develop a list showing how each like-LieMAX big screen concept is equipped (single or dual projection with projector model if possible and any special sound format, like Barco Auro 11. or Dolby Atmos).

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Tom Mundell
Expert Film Handler

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From: Silver Spring, MD, USA
Registered: Nov 2007


 - posted 12-12-2013 03:55 PM      Profile for Tom Mundell   Author's Homepage   Email Tom Mundell   Send New Private Message       Edit/Delete Post 
quote: Bobby Henderson
I don't know if any of AMC's ETX screens have dual projectors.
My understanding is AMC does use duel projectors in their ETX screens; I know at least the ETX at Tyson's Corner 16 uses duel projectors. The one (and only) time I was there getting the two images to overlap was a huge problem for some reason; the trailers were so blurry I complained, the projectionist stopped the trailers several times to try to realign the image. He got it much better than it started but it still wasn't very good. I'm not sure if this is a continuing issue (I have never returned to this theater due to this) or if this was ever a problem at other AMC's.

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Carsten Kurz
Film God

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From: Cologne, NRW, Germany
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 - posted 12-12-2013 06:43 PM      Profile for Carsten Kurz   Email Carsten Kurz   Send New Private Message       Edit/Delete Post 
I heard that recent IMAX digital installs are using BARCO 4k engines. However, real 4k is necessarily IMB based - this will not work with the IMAX image enhancer black box.

They may be using the 4k machines because of some improved brightness and because the pixel pattern is reduced even when showing 2k content. I am sure that these 4k IMAX systems will still be fed 2k over HD-SDI from the image enhancer.

IMAX would need their own IMB with the image enhancer functionality being built in to show real 4k.

Christies DUO works that way - it needs Christie IMBs in both projectors.

Also wondering how digital IMAX does HFR, as they are showing the Hobbit in HFR.
Probably feeding dual 48fps over HD-SDI to both projectors. I doubt, though, that a Doremi Dolphin card supports dual 48fps streams. Maybe they disable/bypass the image enhancer for 3D or HFR, as it is not really needed for 3D.

Anyone with more insight?

- Carsten

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Steve Kraus
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From: Chicago, IL, USA
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 - posted 12-12-2013 06:50 PM      Profile for Steve Kraus     Send New Private Message       Edit/Delete Post 
The ETX screen I am familiar with at a theatre that opened within the last couple of years is single projector.

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Stefan Vogels
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From: Aarle-Rixtel, Noord-Brabant, Netherlands
Registered: Jan 2010


 - posted 12-12-2013 06:53 PM      Profile for Stefan Vogels   Email Stefan Vogels   Send New Private Message       Edit/Delete Post 
They are doing HFR by installing an second doremi server which is than in sync with the master server. They send you 2 files, a right eye version and an left eye version. Each is displayed by the seperate server and projector combo. Imax used Christie CP2000SB and later on the CP2230. They are now over onto Barco to co-develop the laser engines.

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