Noise Reduction Advice

[SameSelf]

Perhaps I am being paranoid, but it seems like everyone on the web recs Neat Video for NR. I have been using Remove Grain in Adobe mainly because I wanted to develop a deep understanding of NR before plopping down cash for a plug-in. I also know that there are other filters out there a la Avisynth. I downloaded the NV trial and played around with it. But I am uncertain if it is worth it or not versus just sticking with Remove Grain in Adobe. IOW, what does Neat Video do that Remove Grain doesn't do?

Thanks

[LMotlow]

That depends on the kind of noise you're working with. Used moderately, NV does a good job of cleaning grungy horizontal tape noise, fuzzy garbage in motion videos, clumpy fades and dissolves, and many forms of mosquito noise. It can also smooth bristly edges and has a very good sharpener (don't push it., though). Especially useful for noisy VHS. Does nothing for things like rainbows. Grain isn't the only kind of noise in video.

Assuming you read the user guide, made suitable test noise samples, and experimented with the filter settings in Advanced mode, then if you don't like it, don't buy it.

[SameSelf]

Thanks. The main noise I am dealing with is due to low light when filming concert hall performances. I don't have the best camcorder and the lighting is very poor. Spotlights on the performers causes over exposure of their faces while the background and everything else is super dark. Here is a very small sample of what I am talking about that shows how the background is super noisy. I don't know what kind of noise this is called and what the best tool is to reduce it. This is 1920x1080p30 video. Thanks.

[jagabo]

The main advantage of Neat Video is that it can be trained to the properties of noise found in your video. That means it can handle much more that just "grain".

[poisondeathray]

"Remove Grain" in Adobe can also sample areas and handle more than "grain" . But it's definitely not as good, and much slower (not GPU accelerated). Play with the NV trial version and see if you like it.

[LMotlow]

The type of clumpy noise that's in the posted image is really tough to remove -- not just for NeatVideo, dfttst ,MvDegrain, or any other filter. Only part of it is "grain". Much of it is chroma grunge that's the residual noise level of the camera and its circuits --a noise level that was either equal to or stronger than the signal that was being recorded. NeatVideo can remove some of it, especially the pixels that move. But examine your noisy low-signal film carefully: you'll find that most of the time the noise doesn't move, or it moves very slowly, and the more of it you remove the more you see that what remains is an almost stagnant pattern that follows the camera's motion.

Even if you could discard 100% of that stuff, you'd have very little image left -- because the noise and the details in some of the objects are one and the same pixel or clump of pixels. What's often done with this kind of noise is to apply moderate doses of two or three denoisers -- NeatVideo being one possibility. Not specific "degrainers", but grain and chroma cleaners like dfttest, fftd3d, TemporalDeGrain, QTGMC, or others. Then run a gradient smoother or unblocker that adds fine grain and dithering to the result. If you don't cover the gaps that were formerly defined by noise removed, you'll have an oddball denuded video with funky edge noise every time something moves. What you would be doing, then, is removing the worst of the noisy crapf and replacing part of it with better controlled, fine-textured, less obvious noise.

Most people try to use NeatVideo as their only video cleaner. That's a mistake. There is no filter that cleans everything. In the image posted, grain isn't the only noise problem in that video.

[hello_hello]

For Avisynth noise removal, I use QTGMC in progressive mode quite a lot. Here's an example.
You'll probably need to open the images full size in their own tabs for comparison, but the second video was encoded with something like:

QTGMC(InputType=1, Preset="Medium", EzDenoise=2)
Spline36Resize(1280,720)
LSFMod(strength=75)
gradfun3()

Then resized back to 1080p for the screenshot.

QTGMC has more options for noise removal you can fiddle with manually.
Like all noise removal, it's not perfect, in that it can have some undesirable side-effects. In the example here someone who's a fan of noise pointed out it removed the detail from the rope running at a 45 degree angle, and there's no doubt it did. Normally, the way it "cleans" edges tends to be a bonus, but not always. Not that it's something I'd notice under normal viewing conditions. I'd be too busy noticing the lack of noise.

There's the odd occasion where I find SMDegrain works better, and sometimes the TemporalDegrain script, but mostly I use QTGMC. I tend to use the medium or a faster preset. The faster presets don't remove as much noise, but they also don't stabilize the remaining noise as much, so any remaining noise still looks natural ("static" noise can look odd, kind of like watching video through a fly-screen door).
Like most noise removal there's generally some sort of compromise between blurring detail and removing noise, especially where there's movement, but I find QTGMC to be better than most noise removal methods in that respect. ie More noise removal, less blurring.

I can't comment on Neat Video as I've never used it.

Edit: Speaking of having never used Neat Video, attached is a very short sample from a video I was playing around with the other day. If someone has Neat Video I wouldn't mind seeing it in action (denoising the sample) and comparing it to the other denoised versions. This is one of those occasions where I think I'd just go with the TemporalDegrain script.

Original vs QTGMC(InputType=1, EzDenoise=6).LSFmod(strength=75) vs TemporalDegrain()

[SameSelf]

This is great feedback guys. NR is definitely an arcane art with a veritable Swiss Army knife of tools. From what it sounds like, the wrong thinking is that Neat Video, or any tool, can do everything that is needed which is the way I have been approaching the problem with Remove Grain. Rather, the true artisan makes use of a variety of tools to get the desired results. Sounds like I need to add NV to my toolkit.