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David Lawrence
4K vs 4K-HD-4K workflows
on Apr 29, 2016 at 4:46:25 pm

Great new article from Oliver comparing 4K to 4K-HD-4K workflows. Big takeaway - 4K isn't all that awesome.

The side by side comparisons really surprised me. Great stuff, Oliver. Check it out:

4K Is Kinda Meh

https://digitalfilms.wordpress.com/2016/04/29/4k-is-kinda-meh/

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Oliver Peters
Re: 4K vs 4K-HD-4K workflows
on Apr 29, 2016 at 6:42:28 pm

Thanks for the shout out. I actually had to double-check some of these to make sure it really was a native versus upscaled version side-by-side. :)

The giveaway in most of these is that Resolve adds a touch of sharpening. When you look at small details in the background, like a sign on a window or the texture of someone's hair the upconverted image (right side) is usually slightly softer and the texture is less defined. Very minor, though. However, things like skin texture on close-ups are a bit crisper due to sharpening.

I think the big takeaway is the value of oversampling in the original image and then that a lot of that value is preserved in the trip to HD and back. Also, most DPs aren't going for very sharp looks. They want something more "filmic". That's inherently soft and fuzzy so it holds up better to scaling. Finally, this is all with progressive-scan media. You get far, far better processing results than with anything shot interlaced.

- Oliver

Oliver Peters Post Production Services, LLC
Orlando, FL
http://www.oliverpeters.com


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Eric Santiago
Re: 4K vs 4K-HD-4K workflows
on Apr 29, 2016 at 8:18:31 pm

Another great article Oliver thank you :)


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Rick Lang
Re: 4K vs 4K-HD-4K workflows
on Apr 30, 2016 at 2:18:00 pm

Oliver, great side-by-side comparisons and it does look that detail is very similar. I wonder if you could clarify the workflow for 4K-HD-4K to confirm what I think you did. I assume these were all graded in DaVinci Resolve 12.x.

The 4K workflow also may be ambiguous, for example, when you label John Brawley's shot of the subject in that lovely coastal home as BMD URSA Mini 4K. That was shot I believe with the URSA Mini 4.6K sensor, in BMD raw 4608x2592. For the 4K workflow, was that put on a Resolve UHD 3840x2160 timeline? If that's what happened, the image already is being fractionally downscaled with some of the inherent benefits of over sampling and detail preservation in the downscaling from the true native 4608x2592 images.

There are two ways to get to the final leg of a 4K-HD-4K workflow that has been discussed on the Cow recently. And they may give different results. The first leg is straightforward, 4K-HD, in which you acquire 4K (or 4.6K) footage and bring it into a HD timeline for work in the Edit/Colour tabs. The last leg, HD-4K, can be done in two ways. I think you may have left the project timeline in HD when you moved to the Deliver tab where you then generated UHD samples. In that method, you have actually used the HD rendered video to upscale that image from HD to UHD. And you've demonstrated the high level of detail retention possible.

The other option for HD-4K is changing the project timeline resolution from HD to UHD (or even 4608x2592) before you go to Deliver. Then when you create your UHD samples in Deliver, Resolve is actually going back to the original footage to render your output. If this is the method used, one is not upscaling resolution at all from the work done in the HD Edit/Colour tabs. I suspect you did the first option so your findings are illustrating the effectiveness of upscaling from HD. The second option though is likely worth investigating though when UHD and HD deliverables are desired. I hope I haven't misunderstood or misrepresented what you have done in my remarks.

Rick Lang

iMac 27” 5K Retina 4GHz 32GB/4GB, URSA Mini 4.6K PL, Pegasus2 R6 24TB, Resolve Studio 12.5


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Oliver Peters
Re: 4K vs 4K-HD-4K workflows
on Apr 30, 2016 at 2:42:58 pm

[Rick Lang] "I assume these were all graded in DaVinci Resolve 12.x."

Yes. Although some of the grades are simple LUTs.

[Rick Lang] "That was shot I believe with the URSA Mini 4.6K sensor, in BMD raw 4608x2592. For the 4K workflow, was that put on a Resolve UHD 3840x2160 timeline?"

Correct. All of the clips were "normalized" to a size of 3840x2160. So 4.6K shots went down to UHD for the "true" 4K version and down to HD and then back up to UHD for the up-converted version. Same for others, like the Dragon clips. The point being that for broadcast or even cinema deliver, you are never going to create a final master at these non-standard sensor sizes. There are some exceptions, of course, but in the context of "normal" production your master is either going to be 4096 or 3840 wide.

[Rick Lang] "I think you may have left the project timeline in HD when you moved to the Deliver tab where you then generated UHD samples"

My size changes were done in the project and timeline settings, not in the Deliver tab. In addition, I also did some comparisons (not shown) between the various up-conversion algorithms - crisper, smoother, etc.

[Rick Lang] "Then when you create your UHD samples in Deliver, Resolve is actually going back to the original footage to render your output."

In this case the only "original source" was the 4K-HD content, when doing this phase of the test.

[Rick Lang] " If this is the method used, one is not upscaling resolution at all from the work done in the HD Edit/Colour tabs. I suspect you did the first option so your findings are illustrating the effectiveness of upscaling from HD"

Correct. I understand the difference. I used the latter to compare up-conversion (4K-HD-4K) against 4K.

FWIW - I had recently delivered a film grade for a client where he'd shot with an FS7 in 4K (UHD). He edited natively to a 1080 timeline in FCPX, gave me a flat file, which I graded in Resolve and delivered back to him. During distribution discussions, they decided they needed a 4K master after all. So he reset his project settings in FCPX and spit out a flattened 4K master file. I ran that through the same project in Resolve, but reset to 4K. Grades lines up and I generated a 4K graded master file for them. In this testing I briefly compared the HD-to-4K route versus 4K-to-4K and saw very little difference. Hence, the reason for this blog post. We did deliver 4K, because it was easy and the right thing to do, however, I doubt anyone would ever see the difference.

- Oliver

Oliver Peters Post Production Services, LLC
Orlando, FL
http://www.oliverpeters.com


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Joe Marler
Re: 4K vs 4K-HD-4K workflows
on Apr 30, 2016 at 3:55:48 pm

Oliver that was a good article. In the pell-mell rush toward 4K it's good to evaluate the cost/benefit at every stage of acquisition, editing and delivery. There are cases (as you mentioned) where 4K can hurt quality not help it. Good quality 1080p can look fantastic. ABC, Fox and ESPN still broadcast exclusively in 720p/60.

I personally like the extra compositional freedom that 4K gives for HD delivery but it has associated costs and complications.

Re 4K-HD-4K there are various interpretations of that. You are mainly talking about post in HD then upscaling. Another workflow is post in HD via proxy, then final render at 4K or HD using the 4K content. Your point is it visually may not make much difference either way, which is interesting.

This should be no surprise since on broadcast TV, good quality 720p/60 looks better than poor quality 1080i/30, even for static images where the higher temporal resolution of 720p has no benefit.

That said, the upscaled quality of some of your comparison images was so striking I looked at them closely, and it may be the scaler or related processing altered the characteristics somewhat. Note the below crops, made from my 5K iMac screen when viewing the original images full size.

https://joema.smugmug.com/Photography/4K-Upscale-Comparison/n-TCbGvr/


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Oliver Peters
Re: 4K vs 4K-HD-4K workflows
on Apr 30, 2016 at 4:24:09 pm

[Joe Marler] "Another workflow is post in HD via proxy, then final render at 4K or HD using the 4K content. "

I'll go into that next week in another post.

[Joe Marler] "and it may be the scaler or related processing altered the characteristics somewhat."

Absolutely. Resolve is not a transparent scaler. There are certainly other options, including After Effects, what's built into various NLEs, and plug-ins. Plus hardware like Teranex, of course. They all have their pros and cons.

- Oliver

Oliver Peters Post Production Services, LLC
Orlando, FL
http://www.oliverpeters.com


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Oliver Peters
Re: 4K vs 4K-HD-4K workflows
on Apr 30, 2016 at 4:30:00 pm

[Joe Marler] " Note the below crops, made from my 5K iMac screen when viewing the original images full size"

BTW - I'm not sure how SmugMug handles sizes, but the side-by-side screen appears to be the right size. When you click on each one individually, they are blown up in size.

- Oliver

Oliver Peters Post Production Services, LLC
Orlando, FL
http://www.oliverpeters.com


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Darren Roark
Re: 4K vs 4K-HD-4K workflows
on May 2, 2016 at 1:19:04 am

2. Many DPs like to shoot with vintage or otherwise “lower quality” lenses. This gives the image “character” and, in the words of one cinematographer that I worked with, “takes the curse off of the digital image.” That’s all fine, but again, viewed natively, you start to see the defects in the optics, like chromatic aberration in the corners, coloration of the image, and general softness.

I'm glad you brought up this point. The other side of this where the director specifically shoots 4-6K with the intent to liberally repo the shot without testing the lenses with the DP beforehand.

I'm surprised how many times I'm having to explain that just because you have 4X the pixels doesn't mean you can punch in 4X.


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