Film-Tech Forum ARCHIVE: Digital 2.35

This is topic Digital 2.35 in forum Digital Cinema Forum at Film-Tech Forum ARCHIVE.

To visit this topic, use this URL:
https://ft-forum.com/ft/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=16;t=001115

Posted by Lincoln Spector (Member # 6835) on 05-18-2012, 07:30 PM:

Hi, folks. Another question from the interested amateur.

How exactly does DCP switch between the two standard ARs? Lens swap?

A projectionist recently told me that it's all letterboxing--same horizontal resolution and smaller vertical one. Considering how many theaters these days are fixed width, that kind of makes sense.

OTOH, what about theaters that aren't fixed width?

Now here's a related story: During the recent San Francisco Intl. Film Festival, I attended a great many digitally-projected films at the Kabuki. All of their theaters open up horizontally for scope.

I don't know what various formats the films were in, but most of them looked good enough to be DCP. And for the scope films, the screen opened up wide.

But two scope films were projected letterboxed within the 1.85 masking, with blank screen on the top and bottom. I know that one of them, a revival screening of Unforgiven, was off of Blu-ray (they messed up the cues and I saw the player's onscreen menu). I have no idea what the other one was off of.

If scope is simply letterboxed, with a shorter lens for fixed-height theaters, why couldn't they do that for non-DCP formats?

Lincoln

Posted by Justin Hamaker (Member # 2165) on 05-18-2012, 07:39 PM:

For 2K content, the chip is 2048 x 1080. Scope pictures are 2048 x 856, Flat pictures are 1998 x 1080.

While doing the projector set up, you create a set of screen files which are like a virtual aperture plate. For each format, you tell the projector where the picture is on the chip (especially scope), as well as any portion of the picture to crop to fit within the shape of the screen/masking. You also set the lens zoom, focus, and shift.

Posted by Dave Macaulay (Member # 813) on 05-18-2012, 08:30 PM:

Assuming they have a digital cinema projector and used it for the blu-ray, there's no technical reason they couldn't have filled the screen.
Often the projector only gets set up by the installer for flat and scope server content. The alternate content channels/presets are often left as-is from the factory, and the lens and screen files may be valid and may not. Setting up a scope DVI preset that fills the screen with HD content should be pretty easy. If it's a non-HDCP compatible projector that's maybe a problem since the video could be DVD resolution and without a scaler the image will be pretty small.

Posted by Jock Blakley (Member # 6552) on 05-18-2012, 10:31 PM:

You can show anything however you want so long as you've got the credentials and brains to set up new lens and screen files - comparable to changing the lens and aperture plate on a film projector.

As Dave points out, in most installations only the DCP flat and scope formats are set up, along with a generic DVI or HDMI input that - if optimised at all - is optimised for 16:9 content. A 'scope Blu-Ray will have the 2.39 picture letterboxed into the 16:9 frame, but it's very simple to set up a new format to show it properly.

It's not as bad though as the Australian Centre for the Moving Image here in Melbourne, who are adamant that touching their projectors renders them DCI-non-compliant and show scope DCPs letterboxed...

Posted by Steve Guttag (Member # 268) on 05-19-2012, 07:09 AM:

This presumes you have enough range left in your lens to zoom it out to 2.39. A DCinema projector's "scaler" will not allow internal scaling if the frame rate is above 48Hz. If it is a 24P output, you should be able to get the projector to scale the 1920x804 out to 2048x858.

Note, BluRays with 1.85 ratios also would need some form of zoom or scaling to not have them be letterboxed.

If one is also zooming the image, the light should also be increased to keep it as bright as "flat."

Posted by Lincoln Spector (Member # 6835) on 05-21-2012, 06:50 PM:

Thank you to everyone for illuminating the situation.

I suspect that the projectionist, dealing with about 100 films over a two-week period, didn't have the time to prepare these two titles better.

Lincoln

Posted by Scott Norwood (Member # 30) on 05-21-2012, 07:02 PM:

It could also be the Blu-ray original. Especially with homemade disks, it is fairly common to see stupid stuff like an image that is both letterboxed and pillarboxed and such. In principle, this sort of thing should be caught in the inspection process and the festival should request a replacement disk from the videomaker, but not everyone is available and sometimes all disks of a given title have the same problem.

The real solution is for festivals to stop accepting DVD and Blu-ray as exhibition formats.

Posted by Lincoln Spector (Member # 6835) on 05-27-2012, 05:25 PM:

Scott--

The only screening that I know was Blu-ray was The Unforgiven. I can't imagine they would have used a pirated disc for something that readily available.

I don't think it would be practical for a large film festival to refuse to play BDs--or even DVDs. As I understand it, festivals can't be picky about what formats they screen. They're getting old and new films from all over the world, in all sorts of formats. It's a big challenge and a big headache.

Lincoln

Posted by Scott Norwood (Member # 30) on 05-27-2012, 05:54 PM:

It depends on the type of festival.

If they are showing mostly recent titles that are making their rounds on the festival circuit, then it is reasonable to limit formats to 35mm, (maybe) 16mm, HDCAM, and (maybe) Digi-Beta. Sundance does this, and it seems to be the trend.

There seems to be a fair amount of mis-communication between festival programmers and "film"-makers. I have seen the same title arrive at one festival on HDCAM and at another on Digi-Beta, even when the second festival had the ability to show HDCAM. I don't know why this happens, but it is irritating to me, and probably also to the video makers.

I can't think of too many reasons why a festival in 2012 should be accepting DVDs for exhibition purposes, unless it is to show an older title that is unavailable on film and which has not been released on DVD. I will admit that DVDs are better than Blu-Rays for festivals with an international focus, due to region-coding issues and such, but it should generally be considered as a format for screener copies only. Blu-ray is just as unreliable as DVD, but at least it looks reasonably good on theatre-size screens, and I can accept that some festivals may have to take it, especially if there is an emphasis on locally produced content.

Posted by Steve Guttag (Member # 268) on 05-27-2012, 08:01 PM:

I too know of festivals that do not accept non-professional media, including DVDs (and probably BluRays). There are just too many problems with them.