Film-Tech Forum ARCHIVE: Can 4k Play on 2k?

This is topic Can 4k Play on 2k? in forum Digital Cinema Forum at Film-Tech Forum ARCHIVE.

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Posted by Jay Glaus (Member # 6011) on 07-17-2013, 05:35 PM:

I just got a hard drive of Grown Ups 2 and it only has 4k versions on it. I have the 4k version ingested on my GDC. Will the 4k movie play on my 2k setup? I have a Barco 2k 32b.
The last thing we tried to play in 4k was a preview for after earth which was waaaaay too big for the screen. I called deluxe and they said that wouldn't happen, it would be fine. What do you think? [Confused]

UPDATE: they had me go in and change the CineCanvas to Always 2k. Hope that will work.

Posted by Carsten Kurz (Member # 5396) on 07-17-2013, 06:03 PM:

2k systems will usually play 4k content without you even knowing.

What exact GDC system are you using? IMBs may need to be prepared for always 2k, but that should be done by the installer.

Read this:

http://www.film-tech.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=16;t=001327#000000

- Carsten

Posted by Justin Hamaker (Member # 2165) on 07-17-2013, 08:04 PM:

I had the exact same issue with the 32B we just installed at my drive-in. The reason this is an issue is because you have a GDC capable of playing 4K content (probably with an IMB). For this reason you have to tell the server to always output 4K content at 2K. If you have a server that is not capable of playing 4K content, this isn't an issue because it always plays at the 2K resolution (I have 5 GDC servers like this at my 5plex).

Posted by Jay Glaus (Member # 6011) on 07-18-2013, 11:32 AM:

Thanks guys,
After I set the GDC to Always 2k it worked just fine and put it out at 2k instead of 4k.
Problem solved!

Posted by Jack Ondracek (Member # 1466) on 07-18-2013, 12:00 PM:

I have yet to see a drive with only 4k versions, so this is interesting.

Are the studios assuming we're all capable of outputting at 2k?

I assume this means longer ingest times & more server space being taken up?

Posted by Steve Guttag (Member # 268) on 07-18-2013, 01:03 PM:

Jack, it is a DCI specification that ALL DCI compliant projectors and servers be capable of handling 2K AND 4K files. When the movie is 4K, then the server/projector must extract the 2K core out of the content. I have NEVER seen a DCP where the 2D 4K feature also had a 2K version with it...there would be no point.

Generally speaking, the only time I see issues crop up with 2K/4K is with subtitling/captioning.

If a server outputted a 4K movie as 4K, then the projector should be able to accept that (you may need to change your input/PCF so that it knows that it is a 4K image coming in.

That said, most servers with an (and it is almost an exclusive IMB thing since it involves 4K) have a means to FORCE the 2K version so the projector can just use its standard Flat/Scope files. Again, the only time I've seen that have issues is on subtitles/captions since they are defined in their own file and place the text referenced from the bottom of the screen.

Posted by Justin Hamaker (Member # 2165) on 07-18-2013, 01:04 PM:

Jack, many, but not all of Sony's features are 4K. This is the End, After Earth and Grown Ups 2 were all 4K, but White House Down was 2K.I've never heard any reason for this, and I don't recall seeing 4K from any other studio (maybe War Horse a few years ago).

Posted by Lance C. McFetridge (Member # 95) on 07-18-2013, 01:13 PM:

I was told that Sony released the drives with 4k claiming backwards compatibility. We had to change our GDC servers from "Native" to Always 2K. Deluxe gave us detailed instructions on how to do it. Which is good because my installation tech still hasn't gotten back to me.
Lance

Posted by Antti Nayha (Member # 4980) on 07-18-2013, 03:16 PM:

For what it's worth, I've seen both 2K and 4K DCP's of "Inception" back in 2010. Those weren't on the same hard drive, though.

More recently, the regular distribution DCP's of "The Dark Knight Rises" and "Skyfall" in our territory (Finland) were both 4K only. I think there are a total of three 4K screens in the whole country, and two of them are operated by our national film archive so they don't play first-run titles...

Also, Michael Haneke's "Love" (Amour) was a 4K DCP - at least the version that toured the international festival circuit last year.

Yes, 4K DCP’s are larger than 2K ones, but thankfully not four times larger even though there are four times more pixels. [Cool]

Posted by Monte L Fullmer (Member # 2797) on 07-18-2013, 03:47 PM:

quote:
This is the End, After Earth and Grown Ups 2 were all 4K,

The Latter two, even shown through a 4K Sony unit didn't at all look like a 4K presentation but more like a 2k since the picture quality looks like labwork wasn't up to par as with their 35mm counterparts.

Now, with "The Guardians", along with some others listed as 4K content and being shown through 4K units, did have excellent presentation results.

Posted by Marcel Birgelen (Member # 6801) on 07-18-2013, 05:44 PM:

The Guardians was a fully rendered movie and a big showoff in technology. Targeting a 4K 2D release probably wasn't hard for them, I guess they will even be ready for a 4K 3D re-release.

Unfortunately, many 4K features are shot on RED cameras. Some movies still shot on 35mm are luckily scanned at 4K, like Django Unchained.

After Earth, although a dreadful movie, had a very cinematic look to it. This is the End was shot on those dreadful RED cameras. I did like the movie, but not the dark, video-ish RED picture. And regarding Grown Ups 2: After trying to endure Jack & Jill I've decided to not come close to anything that has Adam Sandler involved in it in any way, so I cannot judge about that.

Posted by Lyle Romer (Member # 1266) on 07-18-2013, 07:50 PM:

I have to agree with Marcel. The RED cameras (although they are 4k+, I think actually 5k) have a video look to them. The Arri Alexa looks MUCH better even though it is 2.8k or something like that. It looks a lot like film.

It has it's own "look" and doesn't exactly mimic film but it is the closest I've seen from a digital camera. Hopefully Arri will be able to one day produce a 4k version of the Alexa and maintain the other image quality components. Of course, if they keep the super 35 sized sensor increasing the resolution will mean smaller photosites.

The RED cameras look MUCH better than the aweful Panavision Genesis. At least it seems that camera is falling out of favor.

Posted by Scott Jentsch (Member # 1681) on 07-19-2013, 10:42 AM:

quote: Steve Guttag
When the movie is 4K, then the server/projector must extract the 2K core out of the content.

This statement threw me. A 4K DCP has a 2K core, with the extra resolution filled in as extra information?

I wasn't aware of that, and I can't see how that would work.

Can someone point me in the direction of some reference material on the subject?

Posted by Steve Guttag (Member # 268) on 07-19-2013, 11:06 AM:

From the DCI spec (to make sure that the nomenclature is proper). I also only pulled the portions that pertained to a 2K system working with a 4K file.

2.1.1.5.
Hierarchical Image Structure
The DCDM shall use a hierarchical image structure that supports both 2K and 4K resolution files (See Section Section 3.2.1 Image Concepts and Requirements so that studios can choose to deliver either 2K or 4K masters and both 2K and 4K projectors can be deployed and supported. The supported mastering and projecting combinations are illustrated in Figure 3: Hierarchical Image Structure
Media Blocks (MB) for 2K projectors are required to be able to extract and display the 2K-resolution component from the 2K/4K DCP file(s). Media Blocks for 4K projectors are required to be able to output and display the full 4K DCDM. In the case of a 2K DCDM, the output of the Media Block is a 2K image. It is the responsibility of the 4K projectors to up-sample the image.

4.3.
Decoder Specification
4.3.1.
Definitions
•
A 2K distribution – the resolution of the DCDM*7 container is 2048x1080.
•
A 4K distribution – the resolution of the DCDM*7 container is 4096x2160.
•
A 2K decoder outputs up to 2048x1080 resolution data.
•
A 4K decoder outputs up to 4096x2160 resolution data from a 4K compressed file and outputs up to 2048x1080 resolution data from a 2K compressed file.
•
All decoders shall decode both 2K and 4K distributions. It is the responsibility of the 4K projector to upres the 2K file. In the case of a 2K decoder and a 4K distribution, the 2K decoder need read only that data necessary to decode a 2K output from the 4K distribution. The decoder (be it a 2K decoder or a 4K decoder) need not up-sample a 2K image to a 4K projector or down-sample a 4K image to a 2K projector.

•Within 4.3.2:
A 2K decoder shall decode 2K data for every frame in a 4K distribution and it shall decode a 2K distribution. It may discard only the highest resolution level of a 4K distribution. It shall not discard other data such as further resolution levels or quality layers.

From 4.4:
Each compressed frame of a 4K distribution shall have exactly 6 tile parts. Each of the first 3 tile parts shall contain all data necessary to decompress one 2K color component. Each of the next 3 tile parts shall contain all additional data necessary to decompress one 4K color component. The resulting compliant codestream structure is diagramed in Table 7. Assuming D wavelet transform levels (D+1 resolutions), the box labeled 2K_i (i = 0, 1, 2) contains all JPEG 2000 packets for color component i, resolutions 0 through D-1. The box labeled 4K_i (i = 0, 1, 2) contains all JPEG 2000 packets for color component i, resolution D.

A 4K distribution shall have a maximum of 1,302,083 bytes per frame (aggregate of all three color components including headers). Additionally, the 2K portion of each frame shall satisfy the 24 FPS 2K distribution requirements as stated above.

Posted by Carsten Kurz (Member # 5396) on 07-19-2013, 04:50 PM:

quote: Scott Jentsch
This statement threw me. A 4K DCP has a 2K core, with the extra resolution filled in as extra information?

I wasn't aware of that, and I can't see how that would work.

It's actually part of the wavelet encoding that is the compression part of JPEG2000. It encodes frequency components, that is, you can extract individual frequency components and hence different resolutions without rescaling a full 4k decode on 2k systems. The 2k decoder will just 'skip' over the 4k frequency components.

DCI has been criticized for omitting quite a few things, but at the same time other parts of the spec show quite some far-sightedness.

- Carsten

Posted by Mike Blakesley (Member # 26) on 07-19-2013, 06:53 PM:

There have been several trailers that only have 4K versions. We haven't had any problem playing them. (GDC server/NEC projector)

Posted by Steve Guttag (Member # 268) on 07-19-2013, 07:20 PM:

You have a conventional mediablock...they wouldn't have the issue since they are always 2K (unless you decided to do the GDC Quadlink thing...but since your projector is a 2K projector...what would be the point?)

It is with the silly IMBs that have taken the industry by storm that the possibility of dealing with 2K and 4K has cropped up if the tech didn't set things up properly. Note too, some of the IMB systems didn't have the "force 2K" feature on them in early software versions too.

Posted by Manny Knowles (Member # 1171) on 07-19-2013, 09:39 PM:

So...

Are Mipmaps not involved?

Posted by Carsten Kurz (Member # 5396) on 07-20-2013, 06:48 AM:

I think MipMap is a 'concept', but does not define a precise method how to store and process the data. Wavelets may be 'one' possible option. Also, MipMaps seem to be used only for texturing. A lot of textures can be compressed more efficiently with e.g. RLL than with wavelets, and still have the MipMap scheme applied.

- Carsten

Posted by Scott Jentsch (Member # 1681) on 07-24-2013, 12:14 PM:

Thanks for the info -- I'm impressed with the level of foresight in handling the 2K/4K support!

Posted by Jack Ondracek (Member # 1466) on 07-28-2013, 08:42 PM:

quote: Justin Hamaker
Jack, many, but not all of Sony's features are 4K. This is the End, After Earth and Grown Ups 2 were all 4K

Thanks for that, Justin.

After talking to Deluxe about this, I recall that the DCPs for these movies only had CCAP and OCAP versions... nothing about resolution. Based on that, I happily ingested them and gave them no more thought.

In the case of Smurfs 2, my keys specifically state 4K, which is what got me going (again) today.

Deluxe says all will be fine. Apparently, it has been and I didn't realize it.