2K Resolution - 1828x988 (1.85)

F

fdirector

Active member
Hello every one!
Can somebody explain me please how 2K resolution can be 1828x988 if 2K should have more than 2048 pixels horizontally, or it's a S35mm?.

Recently I shot a short on Full HD, so if I'll convert Full HD to 1828x988 it will be 2K 35mm 1.85 right?

Cheers
 
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Why are you converting to 2K? For film-out? Best to just give the film-out place the 1080 file, usually.

Anyway, answer to the 1828x988 question:

Look at a piece of 35mm film. The image doesn't take up the whole piece of film. For example, on one side is the soundtrack.

If you scan a whole piece of film at 2K... you get a scan of the optical soundtrack (cool but not useful for images!)... and a smaller area that contains the actual image. This is how you get 1828x988 from "2K".

Every now and then I have to deliver stuff at one of those crazy resolutions.

But at some point the more modern equipment started actually scanning that subsection of the film at full 2048 across. So you'd get film scans that actually contained 2048 pixels worth of grain... um, I mean "image" :) Beautiful colors though. And similarly, film out places can now write those 2K (or 4K or whatever) images to film.

I can't guarantee you'll see much of a difference on the big screen between 2048 and 1828 though :)

Bruce Allen
www.boacinema.com
 
Hey bruceallen thanks for your reply, very useful!
Yes for film out, or maybe a DCP.
As far as I know DCP projector streams image sequence and audio sequence separately. So if I'll decide to make a DCP out of 1828x988 how do I do that?
 
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Making a DCP is kinda hard actually. Mainly because there is no cheap software that does it in one step.

This one does:
http://www.easy-dcp.de/product.php?id=1
But it's like 2,400 Euro.

There are some freeware DCP creation methods, but they involve quite a lot of technical knowledge.

Also, you still need to check to see if the thing actually plays back.

Other alternative is to look for a friend in a post house. Or find an indie-friendly place eg http://www.indiedcp.com/

Or try to get your film to win a bunch of awards and then beg people. Hmm... maybe all us DVXuser folks should band together and buy a copy of EasyDCP - or hire someone to make the freeware process easier.

Is your film up for Oscar consideration? That's the main reason I run into this thing - friends have something that needs to be filmed out or in DCP format to be considered... all of those official foreign language film entries from all of those different countries suddenly start scrambling around now...

Bruce Allen
www.boacinema.com
 
Here in London a 15min DCP cost about £150. But, I can make it on my home computer using just open source tools (like OpenDCP), it not that hard and takes usually 1 to 2 days to make for 15 mins short. I've tried to make one and then tested it in local theater on a DCP projector using 2.0 500GB USB DRIVE, it's work properly, image quality is very high. Also was tested on easyDCP Player.

But I don't know really if I can do the same with 1828x988 sequence or I should convert it to a 1998x1080 (1.85). I have to try it.
 
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Making a test 2K DCP (5 seconds) using following settings:
Input Video:
Quick Time mov
Overall bit rate: 167 Mbps
Width: 1 828 pixels
Height: 988 pixels
Aspect ratio: 1.850
Frame rate: 24.000 fps

to
TIFF Sequence (1828x988)
to
JPEG200 (1828x988)
2 Threads
SMPTE , 24fps

Audio:
WAV 24 bits
(just 2 channels for test)

===============================================================================================


Output Video:
Video format: JPEG 2000
Bit Rate: 71.4 Mbps
Width: 1 828 pixels
Height: 988 pixels
Aspect ratio: 1.850
Frame rate: 24.000 fps
Color space: RGB
Chroma subsampling: 4:4:4
Bit depth: 12 bits
Scan type: Progressive

Output Audio:
Format: PCM
Format_Settings_Wrapping: Frame (BWF)
Bit rate mode: Constant
Bit rate: 3 072 Kbps
Channel(s): 4 channels
Sampling rate: 48.0 KHz
Bit depth: 16 bits



Will post results soon.
 
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Yoy AMAZING works perfectly! Resolution is amazing. Audio in sync with video.

Cheers.
 
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You shouldn't make a DCP with a resolution of 1828x988 because it is not DCI compliant and there is no guarantee that a digital projector will play it. Some digital servers will even crash if you try to use a non DCI resolution. You should convert the resolution to 1998x1080.
 
Why not? 1828x988 is 35mm Academy 2K, 1.85 isn't it? EasyDCP Player opens it and everything works fine.​
Click to expand...

If you are creating content for digital cinemas, then there are different specification from film.

As I mentioned, 1828x988 is not a DCI compliant resolution. In order to ensure compatibility in digital cinema there are specifications created by the Digital Cinema Initiatives (DCI) by which all vendor and exhibitors adhere. The DCI defines full-frame 2K as 2048x1080 and any image must match at least one dimension of the 2K frame. So, that means your image must be 2048 pixels wide or 1080 pixels high or both. 1828x988 does not meet this criteria. In the DCI, Flat - 1.85 has be defined as 1998x1080 (meets the 1080 aspect) and Scope - 2.35 as 2048x858 (meets the 2048 aspect).

EasyDCP player isn't a validation tool. It will open pretty much anything and play it.

http://www.dcimovies.com/
 
fdirector said:
Here is an 1998x1080 screenshot converted from 1920x1080.
Click to expand...

If your source material is 1920x1080, then you don't necessarily need to do any conversion. If you left it at 1920x1080, it would just be pillar boxed slightly. If you wanted to fill the entire screen, then you need to scale/crop to make it fit the 1998x1080 aspect ratio.
 
@tmeiczin
Yes I know, but, 1920x1080 isn't standard resolution for 35mm 2K for 1.85 aspect ratio.
There isn't much difference, so I prefer to convert 1920x1080 to 1998x1080 and fit standard. By the way, do you know any software aside of easyDCP Player that I can use on computer to test a DCP?
 
@Jim Simon
Yes, 2048 wide is 2K shot on Super 35mm.
1998x1080 is 2K shot on 35mm (1.85:1), called also Digital Cinema 2K
and 1828x988 is 2K Academy offset (1.85:1), also shot on 35mm.
 
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