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Red Footage Moire Problem

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Jason McKee
Red Footage Moire Problem
on May 27, 2009 at 8:13:28 pm

So I have noticed that our footage from the Red which was shot in 4kHD at 23.976fps and then transcoded using RedRushes into 1920x1080 ProRes has a moire issue on certain shots. This is happening much more than I would usually expect from footage shot on film or even other HD cameras. I was just curious if any of you are experiencing this same problem or maybe you have a fix for it. Our final output for the film is 1920x1080 HD and I have tried re-rendering these out using RedRushes in 1920x1080 ProRes (HQ) to no avail. Thanks in advance.
-jm


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Noah Kadner
Re: Red Footage Moire Problem
on May 27, 2009 at 9:54:36 pm

Where are you seeing moire(i.e. on a broadcast monitor or on the desktop) and on what sort of footage? And what were your debayer quality settings?

Noah

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Jason McKee
Re: Red Footage Moire Problem
on May 27, 2009 at 10:28:24 pm

I am seeing moireing anywhere you would normally see it (bricking, venetian blinds, certain fabrics and designs, etc.). The main monitor I use is a Panasonic BT-LH2600W LCD monitor. Although I still see it on the plasma monitor we have here. My debayer quality settings are set at:
Half Res (Standard). Half Res (Standard) is what I was told by one of the guys at RED to put it on. I am a little confused as to what this setting actually means though. Any help is greatly appreciated, thanks.
-jm


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Jason McKee
Re: Red Footage Moire Problem
on May 27, 2009 at 10:28:41 pm

I am seeing moireing anywhere you would normally see it (bricking, venetian blinds, certain fabrics and designs, etc.). The main monitor I use is a Panasonic BT-LH2600W LCD monitor. Although I still see it on the plasma monitor we have here. My debayer quality settings are set at:
Half Res (Standard). Half Res (Standard) is what I was told by one of the guys at RED to put it on. I am a little confused as to what this setting actually means though. Any help is greatly appreciated, thanks.
-jm


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Uli Plank
Re: Red Footage Moire Problem
on May 28, 2009 at 7:15:37 am

Change to half high debayer, even if it takes longer to render.

Then play with:

– detail settings
– OLFP compensation
– scaling algorithm (if you are downscaling)

It's always a compromise between moiré and softness.

Director of the Institute of Media Research (IMF) at Braunschweig University of Arts


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Sean Davison
Re: Red Footage Moire Problem
on May 28, 2009 at 12:27:19 pm

I had this problem because i used the Log and transfer to transcode. When I used Red Rushes it did a much better job

http://www.twotallmen.co.uk


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Jesse Rosen
Re: Red Footage Moire Problem
on May 28, 2009 at 1:55:47 pm

Hi Jason,

When you do a half-res debayer, you will get aliasing as the images are not filtered of high-frequency detail before being scaled. Do a full-res debayer and you should see much less aliasing (at the cost of rendering time, of course).


--
Jesse Rosen
Director of Technical Development
Abel Cine Tech, Inc.
blog.abelcine.com


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Stuart Ferreyra
Re: d Footage Moire Problem
on May 28, 2009 at 2:20:34 pm

At our studio, we never ever use the Half Res (medium or high) debayer for footage to be finished of colored. Lots of people use FCPs log and tranfer but most have no idea that 50% of the detail, quality and latitud data is thrown away.

Only use Log and Transfer for offline editing, then when the program is finished and ready for color or mastering do a digital online at the highest resolution. The render times are slow at around 8:1 but that is the only way to preserve 95% of the quality of the RED camera when downconverting to HD or SD.

Stuart Ferreyra
Timecode Multimedia
Co-owner / Colorist / Consultant

- SD & HD Tape Captures and Tape Outputs
- SD & HD Tape Duplication, Teranex Up / Down /Cross Conversions
- Visit Stuart's studio on the web


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Jason McKee
Re: d Footage Moire Problem
on Jun 11, 2009 at 7:36:15 pm

First off thanks for all your help, all of you. Second... by far the best results I have come up with is using the Full Res ProRes HQ setting in REDrushes. But I too am on an extremely fast machine but am getting nowhere near 8:1 rendering ratio (time-wise). I am closer to 1 frame per second. I have the settings set to 1 clip at a time and use 7 out of the 8 cores per clip. I personally have only noticed a decrease in productivity when changing to multiple clips at once. And the reason I am not using all 8 cores is because I've had it use too much of the resources and then crash when I do this (never had it crash when using 7 cores). Thanks again.
-jm


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Graeme Nattress
Re: Red Footage Moire Problem
on May 29, 2009 at 6:45:24 pm

Half standard is very fast 2k from 4k, and very sharp, and also, can have aliases. Half High uses some very nice filtering as the 4k gets downsampled to 2k, and will produce a very nice looking image with much less aliasing.

Graeme

- http://www.nattress.com - Film Effects and Standards Conversion for FCP


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lisa rolley
Re: Red Footage Moire Problem
on Jun 8, 2009 at 3:53:42 pm

I am also having a similar problem with the RED project I am transcoding in RedRushes - crazy banding issues - its all footage of a nude model on a turntable - pretty dark lighting and when i look at the F proxy i see it on that as well so I am thinking its just how the footage looks BUT i want to make sure.

I am Rendering Full Res in RedRushes to try to get better results but I am curious if the render time is the only disadvantage.

I am running on a VERY fast system:
2 x 3.2 Ghz Quad-core
16gb RAM

Thoughts?

Lisa


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