Have you shot a test chart on 4KHD??? (Graeme, might be up your alley)

[Frank Cueto]

Hi guys. I am trying to figure out whats the best filter to downsample
some 4KHD material we have (shot ont he RED, of course).

And even though I have my footage to try out, I can't tell if I am seeing FAKE sharpness or the real deal.
SOOOOooooo...
I was wondering if any of you out there have a resolution test chart, or any other kind that might help me out to figure out whats the filter in my system thats thE sharpest.

Right now the sharpest render is by actually rendering in half res (1920x1090)
But i would like to render in full 4K (for the benefits of oversampling) and THEN scale down to HD.

Any Help would be most welcome.

 

[Graeme Nattress]

Sharpest filter is "none at all" and it also produces ugly aliases. A guassian filter won't alias, but is soft. Any other filter will be a balance of ringing, sharpness, resolution and aliasing.

Shooting a rez chart is a good idea, but also, it may lead you to produce a softer filter than you'd use for "normal" material, so be careful.

Graeme

 

[Frank Cueto]

So that might be way I am getting the sharpest image by rendering in HALF resolution of 4KHD.

meeehhhhhh.....

Now it becomes a judgement call, oh well.

Thanks Graeme

 

[Graeme Nattress]

The "half good" mode does a nice downsample filter. "half fast" does no filter.

Graeme

 

[Frank Cueto]

Well, thanks, unfortunately I am doing this inside BASELIGHT, so its no quite the same.
Got the guys at filmlight already scratching their heads on this one. Will report back once we know.

 

[Martin Tlaskal]

Well, thanks, unfortunately I am doing this inside BASELIGHT, so its no quite the same.
Got the guys at filmlight already scratching their heads on this one. Will report back once we know.

Hi,

If you want to get the RED SDK to do the down res, simply ensure that the "Medium" proxy resolution of your output format is 1920x1080 - I assume you're using a 3840x2160 RED format as your scenes working format?. Then, when rendering out, select "Medium" as your resolution and BL will use the SDK decode a half-res image using whatever settings you've got in the R3D decode settings.

If you want to have BL do the down-scale, render using "High" resolution to a 1920x1080 output format - this will decode to a 3840x2160 image and down-res to 1920x1080 using BL image transforms. You can change the filtering behaviour by experimenting with one of the many filters available in the Sequence Params UI - you can adjust sharpness for some filters.

I don't think there is one right answer, especially for a zone chart, just experiment and find what works for you. If you have any other questions, let me know.

-Martin

 

[Frank Cueto]

Hi Martin,

I tried rendering a red 4kHD scene setting it at half and all the red sdk setting on max and premium. and it hose come out looking reeeaaalllll good.

So, in my logic, if rendering in medium is good, rendering in full is 400 times better (and slower)...

well, i have tried ALL the filters in the baselight for my transform, and STILL the best looking one is the render I did at medium. I wish i could do it in full because that would mean i get to use all the data for my oversampling and that would help reduce noise a bit (at least in theory)

I actually went ahead and rendered a single footage frame, in medium, and then with EVERY SINGLE setting as far as filters go, to check the results. And for the life of me, the best looking one is the one i rendered in medium....

Maybe I am trying too hard, dunno.... , what do ya think?

If you want to share with me an FTP, PM, me and i'll .rar everything up and send it your way.

 

[Frank Cueto]

Well, I seem to have found a perfect compromise between image detail and aliasing.

And inthe process learned that IF you are rendering full 4K OLPF at HIGH on the RED SDK is a BAD BAD idea ;-)