D5100 - Moire

mojo43 said:
Sorry, one last question... Where did you read about using this filter? I mean, everyone must be dealing with this problem. Did you come up with this solution or did you read about it on another forum? I am having problems bringing up any discussions about using these tools to remove moire.
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It's not really a solution, it's more like a band aid treatment. The real solution is to use another camera.

It can make some footage "usable", but as you may be noticing, it's quite slow to process. If you want slightly better results, use a slower preset setting in QTGMC; "slow" was the fastest one that gave acceptable results. If you read the .avsi or the documentation you will notice there are dozens of settings you can tweak to customize for your footage

Anyways, I use avisynth for a bunch of other stuff - and it has filters for many situations you might encounter in video processing , so I just applied some filters that I had used in restoring some old DVD's (just tweaked the settings abit). It's very powerful stuff, but not very user friendly - there is no nice GUI or buttons to push like some expensive plugin for an NLE or AE
 
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Right, I agree... it's a band aid treatment. I wish there was a way to do it in AE, but I have tried and not come up with anything. Is there any way that you know of in AE or any NLE that is PC based?
 
mojo43 said:
Right, I agree... it's a band aid treatment. I wish there was a way to do it in AE, but I have tried and not come up with anything. Is there any way that you know of in AE or any NLE that is PC based?
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Not for the luminance aliasing, at least not as effective as this method.

For the color moire patterns, I mentioned using chroma blur. This is what people suggested when the problems were first noticed with DSLR footage. It's not ideal , but it does reduce the horrible rainbow colors . The benefit of doing it in avisynth is you can do it on Cb and Cr (the chroma planes), instead of RGB . Most filters in AE or NLE's will work in RGB, but your footage is originally Y'CbCr. The color information is stored in Cb and Cr.

For luminance aliasing patterns, you can use antialiasing filters, but most of the ones that come in NLEs or AE will just blindly apply a 1px vertical spatial blur (only on a per frame basis, it doesn't examine temporal patterns). As a result your footage turns to mush. There are actually pretty good AA algorithms in avisynth as well, but what you want is a temporal solution (one that looks at frame before and after) because it's the change between frames that causes the annoying flicker. So that avisynth method will use temporal motion estimation algorithms - it compares frames before and after using masks to reduce the flicker. It's not blindly applied (i.e the entire image isn't degraded) - it's selectively applied, so only areas that need it are treated. That's why the image retains most of the sharpness instead of a "dumb" blur.

I'm surprised someone hasn't come out with a plugin for this stuff. There would be a market for it. For example, there are retail plugins that are semi-effective for linear skew due to rolling shutter
 
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Wow, you really know your stuff! I have been reading on the settings for the plugins, but this maybe a little over my head. I tried the chroma blur in Vegas but it didn't do anything for the ground unfortunately.... I guess I'll have to take it a step at a time...
 
mojo43 said:
Wow, you really know your stuff! I have been reading on the settings for the plugins, but this maybe a little over my head. I tried the chroma blur in Vegas but it didn't do anything for the ground unfortunately.... I guess I'll have to take it a step at a time...
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The reason is, your ground issues in the footage is a combination of problems.

The chroma blur should work for the rainbow color issues. But you might have to apply several instances in vegas, if the strenght isn't strong enough

The luminance aliasing - the frame to frame changes are equally annoying, but there is no plugin that I know of in vegas that will take care of it very well, without blurring the heck out of the image
 
Right... All I was concerned with was the frame to frame changes where it is flickering (luminance aliasing)... The rest can be dealt with when I shoot.

I am really confused about what this does: FFT3DFilter(sigma=4,plane=3,bt=3,ow=16,oh=16) do?

1. sigma - given noise value for all (or highest) frequencies (float>0, default=2.0) - why did you choose 4?
2. The plane I understand, but why 3? That's for chroma planes and I thought that it was in the luminance?


I think I undestand the rest...
 
mojo43 said:
Right... All I was concerned with was the frame to frame changes where it is flickering (luminance aliasing)... The rest can be dealt with when I shoot.

I am really confused about what this does: FFT3DFilter(sigma=4,plane=3,bt=3,ow=16,oh=16) do?

1. sigma - given noise value for all (or highest) frequencies (float>0, default=2.0) - why did you choose 4?
2. The plane I understand, but why 3? That's for chroma planes and I thought that it was in the luminance?


I think I undestand the rest...
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The goal of FFT3DFilter in this particular case, was ONLY for denoising the chroma planes, Cb and Cr. It's essentially applying a chroma blur. Plane=3 limits the function, so Y' luminance is not touched. It has more functions, but the only purpose in this case was to reduce the rainbow color patterns. If you were to use it on luminace, it would denoise the image (image would become soft, as it becomes more of a "general" denoiser). Try it for yourself, replace plane=3 with plane=4 and preview the script - it will become more blurry.

I chose "sigma=4" because I previewed the script. I tried 2, it wasn't strong enough, so I increased it gradually until it was sufficient. That's how you adjust scripts. You might use completely different values or filters for other footage, you have to customize the filters, you would do the same thing for a filter in AE for example.

If you haven't already, AvspMod is a must for script editing. You can push f5 to preview scripts, you can use tabs to compare multiple scripts and switch between them with the number keys . There are programmable macros, and sliders. It's the closest thing to a GUI for avisynth
 
Oh, I'll give that a try... I haven't used AvspMod. So it was just this line that deals with the flashing ground? QTGMC(inputtype=1, preset="slow", sharpness=0.1)
 
mojo43 said:
So it was just this line that deals with the flashing ground? QTGMC(inputtype=1, preset="slow", sharpness=0.1)
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Basically yes, but mostly the luminance.

If you break down what's "wrong" with the ground, there are 2 major things, 1) the color moire patterns, 2) the luminance aliasing flicker . Both of them contribute to the problems you see on the ground, because the color patterns flicker as well

If you comment out a line (insert "#" without the quotes at the beginning of one of the filter lines), you can preview the script and see what the filter is doing. Adding "#" disables that line, it's becomes like a REM statement
 
Thanks for the tips and the help, I really appreciate it.

I promise to never deep focus again and to use only wide apertures :)
 
mojo43 said:
Thanks for the tips and the help, I really appreciate it.

I promise to never deep focus again and to use only wide apertures :)
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Haha cheers

Just trying to help a fellow moire/aliasing sufferer (used to be Canon 7D for me)

I "stalked" you from the GH1/2 forum post , as it was mislabelled - it doesn't exhibit problems this bad
 
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