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» Film-Tech Forum   » Operations   » Digital Cinema Forum   » Question about 4k (Page 1)

 
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Author Topic: Question about 4k
Geoffrey Hudson
Film Handler

Posts: 12
From: grand rapids, mi
Registered: Jan 2013


 - posted 08-08-2017 02:59 PM      Profile for Geoffrey Hudson   Author's Homepage   Email Geoffrey Hudson   Send New Private Message       Edit/Delete Post 
Hello.
Our theater has a Barco DP2K-10S projector with a Doremi IMS1000.

We are looking into being able to show 4K material, either from DCP or UltraHD discs through one of the external inputs.

I am wondering how hard it is to get there from here with this equipment or if that is even possible.

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Andrew Thomas
Master Film Handler

Posts: 269
From: Pearland, TX, USA
Registered: Jun 2012


 - posted 08-08-2017 03:31 PM      Profile for Andrew Thomas   Email Andrew Thomas   Send New Private Message       Edit/Delete Post 
It's a 2K projector, so you could show the content downscaled, but in native 4K.

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Geoffrey Hudson
Film Handler

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From: grand rapids, mi
Registered: Jan 2013


 - posted 08-08-2017 03:39 PM      Profile for Geoffrey Hudson   Author's Homepage   Email Geoffrey Hudson   Send New Private Message       Edit/Delete Post 
Would there be any benefit in quality in doing that?

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Jim Cassedy
Phenomenal Film Handler

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From: San Francisco, CA
Registered: Dec 2006


 - posted 08-08-2017 03:39 PM      Profile for Jim Cassedy   Email Jim Cassedy   Send New Private Message       Edit/Delete Post 
Your BARCO projector will handle 4K content just fine, but it will
automatically 'downscale' the image to 2K. Noooo problem!

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Frank Cox
Phenomenal Film Handler

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From: Melville Saskatchewan Canada
Registered: Apr 2011


 - posted 08-08-2017 03:51 PM      Profile for Frank Cox   Author's Homepage   Email Frank Cox   Send New Private Message       Edit/Delete Post 
If you're asking what I think you're asking, then the answer is no.

Playing 4k content on a 2k projector will give you approximately the same results as playing 2k content on the same projector.

There's nothing gained (that I know of) by playing 4k content on a 2k projector.

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Carsten Kurz
Film God

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From: Cologne, NRW, Germany
Registered: Aug 2009


 - posted 08-08-2017 05:29 PM      Profile for Carsten Kurz   Email Carsten Kurz   Send New Private Message       Edit/Delete Post 
4k DCPs will play on that system as a 2k DCP. The IMS1000 is not able to play UHD content in 4k, it doesn't feature the necessary HDMI 2.0 input. Content will be downscaled to 1080p to be compatible with HDMI 1.4a.
That HDMI 1.4a input is 4k capable, but only up to 30fps, and it lacks the HDMI 2.0/HDCP2.2 capability needed for UHD. Even if you feed a compatible 4k signal to it, it will be downscaled to 2k, just as with the DCPs.

- Carsten

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Jim Cassedy
Phenomenal Film Handler

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From: San Francisco, CA
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 - posted 08-08-2017 06:39 PM      Profile for Jim Cassedy   Email Jim Cassedy   Send New Private Message       Edit/Delete Post 
quote: Frank Cox
There's nothing gained (that I know of) by playing 4k content on a 2k projector.
Well, I guess nothing other than the fact that you've saved a crapload of money
on not buying a 4K projector. LoL [Razz] (note- - file this reply under: 'sarcasm')

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Leo Enticknap
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 - posted 08-08-2017 10:03 PM      Profile for Leo Enticknap   Author's Homepage   Email Leo Enticknap   Send New Private Message       Edit/Delete Post 
quote: Jim Cassedy
Your BARCO projector will handle 4K content just fine, but it will automatically 'downscale' the image to 2K. Noooo problem!
I can't now remember how I learned this or where, but as I understand it, the JPEG 2000 file structure within the image MXF file(s) in a DCP is such that all DCPs contain the core 2K image data, but 4K DCPs contain extra image data to "fill in the dots," if you will, to complete the 4K frame. The ICP and light engine of a 4K projector playing a 4K DCP will use both sets of data to wiggle the DMD mirrors, but in a 2K projector playing a 4K DCP, the extra "2K to 4K" image data is simply ignored.

So no downscaling takes place when a 2K projector is playing a 4K DCP: the extra 4K image data is ignored, and only the 2K core image data is read and processed.

I'm guessing that this stripping out happens in the server, media block or IMB: in the config setup scripts for most if not all the models I've encountered, you are required to state whether the projector is 2K or 4K.

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Marcel Birgelen
Film God

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From: Maastricht, Limburg, Netherlands
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 - posted 08-09-2017 01:06 AM      Profile for Marcel Birgelen   Email Marcel Birgelen   Send New Private Message       Edit/Delete Post 
quote: Geoffrey Hudson
We are looking into being able to show 4K material, either from DCP or UltraHD discs through one of the external inputs.
I guess you're running a normal cinema operation and regularly play DCPs from common distributors.

In that case, you probably have already played a whole bunch of 4K DCPs without even really noticing.

Obviously, as others have pointed out, your equipment isn't capable of rendering 4K resolutions, simply because the light engine is stuck at a 2K resolution. Like Leo mentioned, the "rendering engine" in your IMS will only extract the "2K part" of the image from the DCP, even though the DCP itself is a 4K DCP.

If you connect a UHD capable Blu-Ray player, it will downscale it to FullHD, because like Carsten already mentioned, the IMS doesn't have the necessary HDMI 2.0 port and will also not handle the required HDCP level.

So, in order to do proper 4K, you have to upgrade your equipment.

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Monte L Fullmer
Film God

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From: Nampa, Idaho, USA
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 - posted 08-09-2017 02:59 AM      Profile for Monte L Fullmer   Email Monte L Fullmer   Send New Private Message       Edit/Delete Post 
Thing one really has to watch out for is when the cinema owners are advertising features and saying that the presentation is in 4k when your equipment only displays 2k.

One hears a lot of this, but usually in reverse if the cinema advertises features shown in 4k when the feature is only in 2k, and they do have 4k equipment..like "projection from SONY 4K projectors.."

Bottom line is that only a spattering of features at present, are scanned in 4k resolution.

It's still a 2k world out there.

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Steve Guttag
We forgot the crackers Gromit!!!

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From: Annapolis, MD
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 - posted 08-09-2017 05:30 AM      Profile for Steve Guttag   Email Steve Guttag   Send New Private Message       Edit/Delete Post 
Leo,

A projector will downscale a 4K image to 2K (done in the ICP or equivalent). A SERVER will extract the 2K core from a 4K DCP. So, in this case, the IMS1000 delivers a 2K image to the projector and the projector is unaware that it started 4K.

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Bobby Henderson
"Ask me about Trajan."

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From: Lawton, OK, USA
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 - posted 08-09-2017 09:13 AM      Profile for Bobby Henderson   Email Bobby Henderson   Send New Private Message       Edit/Delete Post 
Most people really don't properly understand concepts of resolution. They don't understand the relationship of native resolution between hardware (projector, HDTV, etc) and software (video file stored in a DCP, Blu-ray, etc.). In order to have true 4K both the hardware and software must match or even exceed that 4K level. Of course you'll get the best looking results from a pixel for pixel match of hardware and software.

There are people buying Ultra-HD Blu-ray players and attaching them to their old 1080p HDTV sets, thinking that new player will make their TV "4K." But not to worry: most of the titles being sold on Ultra-HD Blu-ray were up-scaled from 2K sources. So it's mostly bullshit anyway. "How's that new HDR video looking on that 10 year old TV set, Cletus?" The movie studios couldn't give a shit about the misunderstanding; they'll happily take advantage by screwing the customer with a fake product. But then most of the general public doesn't give a shit about movies on disc anymore either. Notice all the shuttered video stores lately.

Doing graphics work I run into the problem of people not understanding resolution on a regular basis. It's really common when trying to help customers create graphics or video content for LED signs. LED boards can be configured in many different shapes, sizes and resolution/pixel-pitch levels (according to how much the customer can spend). It's difficult to get customers to take the right steps in tailoring their content to work on those displays. They'll go shoot a video with their phone or even a pro setup and then expect the sign to play the video just like a TV screen. They don't consider how the sign may crop the video or how its thousands of pixels won't be able to render all the 2.2 million pixels of detail in the video. Their complex video or group photo gets turned into unintelligible soup when down-sampled to their little 48 pixel tall by 128 pixel wide LED sign. All I can do is tell them "the more simple you make the image the better." I've even run into other graphics people who don't have a proper grasp of the concept. "How many DPI should I make this JPEG?" Ugh.

When customers ask what kind of logo files they should send for a project my response usually goes over the head. "What's vector art? What's resolution independent or scalable mean?"

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Jordi Aguila
Film Handler

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From: Barcelona / Spain
Registered: Feb 2017


 - posted 08-09-2017 10:37 AM      Profile for Jordi Aguila   Email Jordi Aguila   Send New Private Message       Edit/Delete Post 
Do you know if there are any veeeery old server that can not be able to reproduce a 4K DCP?

We're going to do a big delivery in DCP 4K and we want to be sure that 4K is accepted by all servers.

Thank you.

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Carsten Kurz
Film God

Posts: 3681
From: Cologne, NRW, Germany
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 - posted 08-09-2017 12:07 PM      Profile for Carsten Kurz   Email Carsten Kurz   Send New Private Message       Edit/Delete Post 
I don't know any strict DCI compliant servers that can not play 4k J2K.

Some 'DCI compatible' players in some areas of the world (e.g. beefed up E-Cinema servers with J2K capability), or some software players that may run on a festival may fail on 4k. But I wouldn't call these cinema servers. There have been quite a few 4k-only mainstream releases, so, if 4k would be an issue, they wouldn't do that. And I never heard that there were issues with these releases. the 4k compatibility layer was in the specs very early on, and every manufacturer of J2K capable DCI servers knew this and built them to that spec.

- Carsten

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Leo Enticknap
Film God

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From: Loma Linda, CA
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 - posted 08-09-2017 11:27 PM      Profile for Leo Enticknap   Author's Homepage   Email Leo Enticknap   Send New Private Message       Edit/Delete Post 
quote: Steve Guttag
A projector will downscale a 4K image to 2K (done in the ICP or equivalent). A SERVER will extract the 2K core from a 4K DCP. So, in this case, the IMS1000 delivers a 2K image to the projector and the projector is unaware that it started 4K.
Thanks - that makes sense. Hence the reason why, when running the config script of a server that is being used in a Series 2 system with an IMB, you have to specify whether the projector is 2K or 4K. If you specify 2K, only the core 2K image is sent through the backplane to the ICP; but if you specify 4K, the extra image data goes as well. If you misconfigure (specify that the projector is 4K whereas in fact it's only 2K), then downscaling will be done in the ICP.

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