stage at which to go from 4k to 2k

[hans de vries]

Hi all!
I was thinking about the following: are there consequences as to the moment you turn 4k into 2k? I shoot 4k 2:1, most of the time I export qt prores 2k from redcine but I found out that fcp will accept 4k material--magic bullet won't work though--and I expect that in the near future all applications will work with 4k, which makes the question more important: does it matter whether you turn 4k into 2k already in redcine or redalert, or would there be benefits to wait until you export footage from fcp?
Hans

 

[hans de vries]

was this a dumb question or is everyone clueless?:sad:

 

[CraigDavidson]

It is a good question. RAW r3d files (2:1) are 4096x2048. FCP does have a limitation of 4000. The RAW files are in Bayer format, each pixel location has only one channel of color, and the decoder has a sophisticated debayer algorithm to extract and reconstruct the original RGB color at each location.

If you convert to ProRes, you are changing to a YUV 422 format, which reduces the chroma resolution, effectively throwing out half the color information.

Many people convert to HD ProRes and do a proxy assembly, going back to the original r3d files for a reason. FCP is much happier with 1920x1080, ProRes as 422 has less data to decompress than an RGB (444) file, and when you conform back to the original source at the end, you theoretically have access to all the original RAW data and resolution.

If you want to do an on-line edit, you should consider converting to 2K 444 - full RGB.

 

[Kaku Ito]

hans,

I edit proxies in most cases, but for optimum and efficient workflow, I handle (this means put the footage in the list and drag needed clips to FCP), edit look with Clipfinder 2.2, edit proxies in FCP, then export XML, open Monkey Extract and render to uncompressed 444 or DPX with the XML from FCP.

This way, you can decide wether you output 4k or 2k or even smaller at the Monkey Extract rendering.

The key is to edit proxy, then decide the resolution when you render. Adobe Premiere Pro CS4 provides this all within itself and plus dynamic link function with After Effects with proper proxy/R3D handling. Amazing.

 

[hans de vries]

Thanks to you both!
I guess I knew I just had to edit the proxies and at the end return to the originals; I just crave the best image I can get at every stage of the process and tend to drift away in color correction etc. during editing; I have a hard time waiting for someone else to do it later on. By the way, I have imported 4096x2048 footage and fcp doesn't seem to change it. At least, when I click info it gives me the same numbers.

 

[CraigDavidson]

FCP 6.0.5 allows you to import a 4096x2048 clip, but if you place it on the sequence, and let the sequence change to match, the sequence is set to 4000x2048.

 

[hans de vries]

I realise now fcp never asks me anymore if I want to change the settings to match everything up; I guess it's given up on me:001_rolleyes:It probably isn't very helpful to let it stay 4096.
Thanks, Craig

 

[Nick Gallegos]

I realise now fcp never asks me anymore if I want to change the settings to match everything up; I guess it's given up on meIt probably isn't very helpful to let it stay 4096.
Thanks, Craig

FCP will only ask to match sequence settings when you initially drop a video clip onto a new timeline. Everything else dropped in will be adjusted to conform to the original sequence parameters by design.

If this is no longer working for you, go into the "Editing" tab under User Preferences and make sure the Auto Conform option is set to "Ask."

You can of course change the sequence settings later (Cmd+0 on the active sequence), but it will change EVERYTHING on the timeline to match the new settings.

 

[Allen Abrahams]

It's also important to remember is that with 10 bit color you have 1024 shades of grey and 12 bit with 4096 shades of grey. Your R3D files are 12 bit, way more latitude, supposedly more than super 35mm film. If you intend to reduce to 10 bit, do your color correction and grading in 12 bit, it does result in a better 10 bit image... If you convert to ProRes or use Color you are only getting 10 bit.

 

[Blair S. Paulsen]

One option is to grade and downrez right away

One option is to grade and downrez right away

The short answer is 4K for acquisition only, 2K (or 1080) in post.

The longer answer depends on issues like what your deliverables are, particularly small screen vs theatrical. Are you home cooking everything or working with a facility? Will the project pass through a lot of hands? Will there be a color grading pass? Etc.

Theoretical discussions are fun but if it turns into the equivalent of lighting a candle on a motorboat going fast then it really doesn't matter.

In my business model I offer several pipelines to match project parameters. One topology I think might be of use to this thread is where we do what is often referred to as "one light" color grading in Scratch then feed out to the AJA io/HD box via HD-SDI in real time and write hardware encoded ProResHQ onto the Mac. The client then has a high quality FCP friendly file ready to edit and the primary color grade was done properly on the RAW files. There are some downsides to this approach for some productions but for others it is very effective. YMMV.

Cheers-

Blair S. Paulsen
4K Ninja, RedOne #19
San Diego, CA

 

[hans de vries]

thanks for all your contributions! The project will end up at a professional facility in Amsterdam, and thank god for RAW, whatever I mess up they can easily correct it. It´s just that I was educated as an artist, I can´t withstand the urge to mess with the image to see what I come up with, ofcourse hoping it will be something noone else has done yet. Which, I admit, is not very likely, but you never know.
Hans