Resolution Anomaly?

[DB Hansen]

Hello,

I've been working on 4K R3D files in post, doing compositing and FX. My first experience with Red footage (thus my first post) and it's been great.

However, I ran across something recently that has me puzzled. Watch the below clip of a screen cap from REDCINE-X. You'll see me step through the clip frame by frame. Pay attention to the edge of the white shirt, the folds in the jacket, and foliage in the background. The only way I can think to describe this is that suddenly the resolution drops in half? It looks like an interlace issue, even though this footage is not interlaced. I don't notice any cadence or pattern to why or when it happens, only that most of the clip seems to be of the lower resolution. If you watch the end of the clip, I shuttle through faster and the edges of the jacket start to "shimmer." I thought at first it was the result of a rack focus, but ruled that out.

I'll admit to not knowing any of the technical details about how it was shot (camera, settings). I can find out if necessary to solve this, although I suspect there is no way to fix it. Sadly, it's compromising some of my FX.

So far this is the only clip I've noticed doing this.

Also, FYI, generally importing into AE using "as shot" and default R3D settings (Debayer quality high, OLPF OFF, chroma denoise NONE, RC2+RG2)

Thanks for any help.

DB



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Mac Pro 2.4GHz 8-core, 64GB RAM, OSX 10.7.3
REDCINE-X 506, Adobe AE

[Joseph Coleman]

did you render it out to see if the problem was still there? it may just be a viewer issue in redcine X.

[DB Hansen]

Actually I noticed it while working in AE. I went back to REDCINE-X to confirm it wasn't how AE was importing it.

I think my only true saving grace is that we're conforming in 2K, so downsampling in AE out to final renders will result in a little smoother look. It's still there in the 2K output - just not as distinct.

[Marc Wielage]

What Redcode compression rate were you at? 3:1? 5:1? 8:1? I'm wondering if there was just a mild data corruption and it's showing up as a motion artifact.

What happens if you debayer the R3Ds back out again as DPX and view those?

You may want to contact Red support and have them take a look at the file. In a lot of ways, this is a good reason for having a sharp-eyed assistant editor (or assistant DIT) to inspect all the footage every night after shooting, just to make sure there aren't any visual anomalies. This is no different than the old school of film dailies, where we'd often get calls on whether the negative was scratched or fogged, just so they could release actors or strike sets. It didn't happen often, but I can recall a few awful occasions where film damage did happen, during the shoot or afterwards. Data is just as fragile as film in some ways, only cheaper and less predictable.

[DB Hansen]

Well, tried the DPX export to 4K from REDCINE-X, using full quality debayer settings and I'm seeing the same thing.

For the record, here's the metadata on the shot: RED ONE, Mysterium-X S35, REDcode 9:1 (REDcode 36).

We may just have a corrupt file. Not sure what the QC was on set with the DIT, but you're right - it's worth having super close scrutiny these days with dailies. Securing data backup is only part of the much larger picture of image integrity.

And definitely fragile. In fact, moreso than film because much more of it is stored in singular locations. Poof, and it's gone.

[John Marchant]

Looks to me like the codec had a hard time with a super complex image. I could be entirely wrong, but genius as it is, Redcode has its limits.

[Noah Yuan-Vogel]

Looks to me like the codec had a hard time with a super complex image. I could be entirely wrong, but genius as it is, Redcode has its limits.

But REDCODE is Intraframe and these frames are not changing much, so it has trouble with some frames and no problem with some nearly identical frames? That kind of inconsistent behavior would be a significant problem. It really does look like vertical resolution is dropping in half for certain frames.


Could you post the r3d?

[DB Hansen]

True. You're looking at close-up of a much wider shot with a heck of a lot of leaves and dappled light.