2:1 aspect ratio

Anything and everything to do with DCP-o-matic.
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shanemalone
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Joined: Sat Nov 03, 2018 2:26 pm

2:1 aspect ratio

Post by shanemalone »

Hey all,

I work for a cinema chain and recently my fellow engineers and I were tasked with creating a 2:1 ratio for each screen we have. There is currently no 2:1 container ratio in the software, is there any plan to include it, or even perhaps allow custom container specification?

I got a shock upgrading to the latest this morning, but found the setting to reveal the rest of the ratios.

Cheers,
Shane
carl
Site Admin
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Joined: Thu Nov 14, 2013 2:53 pm

Re: 2:1 aspect ratio

Post by carl »

What size is your 2K frame? 2048x1024?
IoannisSyrogiannis
Posts: 92
Joined: Mon Nov 13, 2017 8:40 pm

Re: 2:1 aspect ratio

Post by IoannisSyrogiannis »

Your task is to make screen, masking, zoom settings to use that, probably contained in a flat DCP/frame.
Making a 2:1 DCP (similarly making a 1,77:1 or 1,66:1), won’t help you with professionally made DCPs, except if your goal is to make a test pattern.
My five cents would be to get information on what exactly is the purpose and make a test pattern accordingly.

It would be even better if you could get a test pattern DCP from the production company.
Carsten
Posts: 2075
Joined: Tue Apr 15, 2014 9:11 pm
Location: Germany

Re: 2:1 aspect ratio

Post by Carsten »

Container and display aspect ratio are two different things. Most current DCPs using 2.0:1 aspect ratios use a flat container with an 1.85:1 ratio, and mask with black bars on top and bottom to 2.0:1 (typically, creating a 1998 by 999 active image in a 1998 by 1080 container vertically centred). When creating a suitable screen preset based on flat, one will typically zoom into that image a bit to fill the screen vertically, while the display width is increased as well (as screen geometry and masking allows).

You will see it handled like that e.g. with the current Jurassic World DCP. Also the trailers are in 2.0:1.

vlcsnap-2022-06-16-13h27m30s319.jpg
vlcsnap-2022-06-16-13h27m30s319.jpg (309.92 KiB) Viewed 87 times


The aspect ratio handling in DCP-o-matic has been revised over the 2.15->2.16 transition. While I understand that it may be confusing at first to not see the common list of typical aspect ratios immediately any more in the current release, the current way of dealing with scaling and aspect ratio is much better than previously. Believe me, we reasoned about that scheme A LOT!

Wether you want to create your own framing chart for screen adjustments, or actual 2.0:1 DCPs, that makes a difference. Framing charts are usually created using full containers (2048/1080 or 4096/2160 containers). So you can have adjustment/cropping marks outside of the active frame.

If you want to create 2.0:1 content that uses 2.0:1 projector presets compatible with common DCPs using that aspect ratio, just use 2.0:1 content and put it into a flat container with no rescale/cropping applied. If your content is not 2.0:1, you can still crop it in DCP-o-matic to that aspect ratio if needed. However, when you use it with a proper 2.0:1 projector preset, the projector will crop it to 2.0:1 anyway.


I praise every cinema striving to create actual 2.0:1 presets instead of just showing these 2.0:1 DCPs letterboxed as many studios now actually advise to avoid complications. While 2.0:1 DCPs were a rare species until recently, I guess that ratio is here to stay. Netflix, Amazon, Apple etc. are creating a lot of content in that ratio now, and some of that hit's the big screen without a previous flat or scope consideration.
IoannisSyrogiannis
Posts: 92
Joined: Mon Nov 13, 2017 8:40 pm

Re: 2:1 aspect ratio

Post by IoannisSyrogiannis »

Did anyone here receive in the past any 2:1 test pattern along with a 2:1 DCP?
There are some mentions that streaming services are not much bothered with the cinema exhibition, but there might be a bright example out there. I remember using the Dunkirk one on a cinema to get 2,2:1. Is there any 2:1 out there in the wild?
I would prefer having that, instead of changing between a feature DCP and ICP test patterns (for the sake of focus), having to zoom in and out to make sure nothing is left out.
Carsten, do you have any idea where the odd pixel/line is missing, top or bottom?
(1080 is an even number, 999 is odd. So, on one side, top or bottom, there should be an extra line turned into black, to fit the aspect ratio.)
Carsten
Posts: 2075
Joined: Tue Apr 15, 2014 9:11 pm
Location: Germany

Re: 2:1 aspect ratio

Post by Carsten »

I have seen a few movie specific framing guides that came on the same hard disc as the movie itself. However, since we get most content now through Gofilex, etc, I haven't seen one in recent years. But, one is probably sufficient, as all I have seen used the same 1998/999 active image area vertically centred. I think I created a 2.0:1 preset in 2015 for the first Jurassic World, and never had to touch it again since then.

I don't think there is a proper spec with regard to the odd line. Usually, that's small enough to not bother about.

I know I stored a few framing guides on our projection machine...

...funny, most of those I stored are for movies in standard format, e.g. Captain America (2.39), JungeBook (1.85), etc.
I have the Dunkirk framing guide as well, plus, the odd 'Tomorrowland' in 2.20:1
The only 2.0:1 I have is the one I created myself with DCP-o-matic.

We will be playing 'The Northman' shortly, and a colleague advised me that a 2.0:1 framing guide would come with the electronic distribution package.
IoannisSyrogiannis
Posts: 92
Joined: Mon Nov 13, 2017 8:40 pm

Re: 2:1 aspect ratio

Post by IoannisSyrogiannis »

Well, if that is indeed the case, I would welcome a pattern.
Carsten
Posts: 2075
Joined: Tue Apr 15, 2014 9:11 pm
Location: Germany

Re: 2:1 aspect ratio

Post by Carsten »

Hi Ioannis,


I sent you a link to two official 2:1 framing guides per forum personal message.
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