Recommended 4k to 1080 downscale method?

[Andy_Johnson]

So this is something that I've seen a bunch on, but have never quite wrapped my head around.
What's the "recommended" method for down-scaling final video output to 1080 from 4k?

I'll use a very basic workflow as an example (only using FCPX in this case)

Should I:
+ Edit footage on a 4k timeline, export 4k master file, downsize to 1080 in compressor (or other)?
+ Edit footage on a 4k timeline, export 1080 master file from FCPX?
+ Edit footage on a 1080 timeline?

Are there any tricks to get that "crisp-ness" on the 4k -> 1080 downscale?

Thanks!

 

[Daniel Schweinert]

It's like photo editing in Photoshop you have to resharpen after a downsize to get that crisp-ness:
-Edit footage on a 4k timeline, export 1080 intermediate codec like ProRes422HQ

Add a sharpening pass (usually with unsharp mask in AfterEffects good starting point is Amount 40 / Radius 0,8) on that ProRes422HQ 1080 file and export to whatever you want for delivery H.264, ProRes422HQ, ...

 

[Chris Henze]

I always edit in the form of the final delivery. When you shoot in 4,5, or 6k and edit in 2k there are a lot of options for reframing. I finish in Davinici so each scene is looked at in its final form and sharpened accordingly. Reframing is a very powerful tool.

 

[Marc Wielage]

I also think that sharpening can be a very crude tool in the wrong hands. You need to sharpen selectively and carefully so you aren't sharpening the whole thing -- only the elements that are most important in each shot. There is no one-size-fits-all setting that works for the entire frame, and the risk is over-enhancement and artifacts.

In truth, I often wind up softening parts of the image that stick out too much, or cutting back on skin focus as a beauty pass. I think sharpness in and of itself is only one of a dozen factors that goes into making a great picture.

 

[M.Halsell]

In your spare time, I would grab some sample footage with high contrast, high detail and add a zone plate. Run the test footage thru each of the scenarios you suggested or expect to be part of your workflow. This will help train your eye to data loss and artifact introduction during resample senarios. Sharpening is a very delicate tool, as image enhancements can be introduced even after delivery such as codecs and displays. Sharpening can easily be overdone, particularly after a downsample as the image perceptually can seem a bit soft, with the result being dancing pixels, jittery lines and halos. Also, resampling changes grain structure.

Once you get a good handle on when and how to use adaptive and non adaptive filtering, you'll never need to revisit the topic again.