4K -> what size? -> 2kDCI + HD + SD

[Chase Gordon]

I shot in 4K 2:1, framed for 1:1.85. I want to deliver a 2K DCI at 2048 x 1080, HD at 1920 x 1080 and 1280 x 720, and SD 640 x 480. I can't really handle 4K through the whole pipeline, so the question becomes what size to convert the 4K to.

Except for SD, I feel like all these other formats are close enough to 1.85 I could just scale the 4K to 2048 x 1080, losing some of the sides of the image, and deliver the DCI full frame, continue trimming the sides to get to 1920 x 1080, do a simple shrink to get to 720, and avoid letterbox until I get to the SD. The other option would be to post at 2048 x 1024 and letterbox the DCI and HD 1080, but that puts my DCI at 2:1, which is noticeably "off" of any kind of standard viewing ratio, and creates a weird ratio for the 1080.

What do you guys suggest?

And if I do scale, any suggestions on how to choose which interpolation method to use? Graemme has given me too many options.

 

[Thomas Mathai]

This is a conversation you should be having with the post house doing your DCI, since they will know what is needed.

 

[M Most]

I shot in 4K 2:1, framed for 1:1.85. I want to deliver a 2K DCI at 2048 x 1080, HD at 1920 x 1080 and 1280 x 720, and SD 640 x 480. I can't really handle 4K through the whole pipeline, so the question becomes what size to convert the 4K to.

DCI is the name of a consortium of motion picture studios that was formed to create a specification for digital cinema. What you're talking about (at least what I think you're talking about) is a Digital Cinema Package, or DCP. Who exactly are you delivering to, and why do you need to create a DCP for this delivery? You should know that creating a DCP is not exactly desktop, do it yourself work. It is not trivial, and requires a very thorough knowledge of the specification, proper viewing conditions with a digital cinema server and projection environment to review converted files, and rather specialized software to create a DCP that is an acceptable deliverable that will work in most digital cinema servers. Unless you are prepared for all that (and by the questions you're asking, I would guess that you're not - for one thing, you don't seem to be aware of the actual frame size requirements for DCi compatible 2K projection), I would suggest contacting a company that creates DCP's on a regular basis and asking what it would take to have them do one for your project - if you actually have a requirement for one.