Noise Reduction

[Tom Chase]

Quick question for everyone - what the best workflow for adding Noise Reduction?

I want to purchase NEAT, I edit in Premiere & grade in Resolve (lite).

Is it better to add NEAT to the end of a Resolve node tree and render out back to Premiere or just do the grade and then add NEAT to the rendered files in Premiere?

I feel like this question has been asked before - but any input would be great (most of my work is for web based productions & film festivals)

Tommy

 

[Marc Wielage]

There's a couple of different ways to do it. Depending on the power available to you on the machine running Resolve, you can run NR as the last node grade in the tree. But typically, OFX plug-ins are problematic and suck a lot of processing power, so real-time playback is very demanding.

The least problematic way to do it would be to export a color-graded pass as a flattened file, then round-trip the file back through Resolve (or After Effects or whatever host you want) and apply the NR there. If you wanted to do scene-to-scene NR -- which I strongly recommend -- then I'd do it all within Resolve as a final step.

 

[Tom Chase]

So you wouldn't go into your NLE and add in Premiere or Avid then? I get what your say which the round-tripping.

 

[Marc Wielage]

So you wouldn't go into your NLE and add in Premiere or Avid then? I get what your say which the round-tripping.

Not unless you have a calibrated monitor you can trust. The problem with doing heavy-duty processing in editing is that 95% of the editors I know are just using cheap $200 computer displays, all of which are 8-bit, none of which are reproducing decent Rec709 color. There's always a chance the display is enhancing the noise and making it look worse than it really is.

If you have a calibrated external display, then it's possible to get a decent picture out of Avid or Premiere or FCP or anything else, at least in terms of judging sharpness and noise.

The trick with using noise reduction is that there is no "one size fits all" adjustment that will work for the entire show. You need to crank it up for the shots that really need it, bypass it for the shots that are good, and have a medium setting for mildly-noisy shots -- and have the ability to program these settings on a scene-by-scene basis.

 

[Tom Chase]

Marc & Egon thank you this is very helpful.

Egon, it seems like you'd do the NR first if I am understanding what your saying... doing it on the raw on the image. Please correct me if I am miss understanding.

 

[Milan Spasic]

Interesting.

Don't want to highjack the thread but could anybody comment on differences between using NEAT plug-in in either Resolve or Premiere vs using the noise reduction controls in full version of Resolve?
I have a project coming up that will be shot entirely at night, under the street lights and am wondering if it's worth splashing out for a full version of Resolve just for this feature.
Already have NEAT .....

 

[Marc Wielage]

the noise reduction wants to go on the raw footage , before other processes basically .. doesn't matter what software uses neat .. just make sure you remove the noise at source.. then do your stuff...

I generally don't agree with this because grain can increase or decrease depending on how hard it's slammed in color-correction. If you don't know how it's going to change in the color process, you don't know where to set the NR knob. Noise-reducing Log images is problematic as well, because noise itself is drastically magnified by increasing contrast. The same shot in low contrast might actually appear to be OK.

 

[Tom Chase]

Marc,

That's kind of why I asked the question to begin with - if you do your grading and complete it in Resolve (which most forums suggest doing NEAT or any NR plug-in last in your node chain), why wouldn't you export it and do the NR in your NLE?

 

[Michael Tiemann]

I generally don't agree with this because grain can increase or decrease depending on how hard it's slammed in color-correction. If you don't know how it's going to change in the color process, you don't know where to set the NR knob. Noise-reducing Log images is problematic as well, because noise itself is drastically magnified by increasing contrast. The same shot in low contrast might actually appear to be OK.

True, but...Resolve makes it easy to visualize the NR after applying a LUT or other image processing. And its NR allows you to apply NR to very specific parts of the image--be they shadow regions, colored regions, and/or regions that very specific spatial or temporal relationships. Resolve's extraordinary precision helps to ensure that small numbers in log space remain accurate numbers in more normal gamma space. You are absolutely right that our eyes can mislead us looking at RAW or (heaven forbid) linear light to make a NR decision. But we can still do the math where it works best for the image while evaluating it with a gamma that works best for us.

At the end of the day, there are some kinds of noise you probably want to remove at the start of the imaging chain, and other kinds that are OK to deal with at the end.

 

[Patrick Tresch]

As Marc said.

IMHO apply Neat NR at the end of the line (also last node in comp).

As it has to map the noise/artefact level wich usually appear only after applying the grade.
It won't apply the same noise pattern if you have a R3D @ 800iso or if you push it to 5000 iso. So there is no way Neat handles a noise pattern once for all for a file.

That's my understanding of Neat denoiser.

Pat

 

[Tom Chase]

AHHHHHHHHH - NR is so damned confusing. So I should get the OFX version not the premiere is what I am getting out this. It also seem from Marc's comments that there is no one right place to apply NR. Sorry guys I'm really new to using NR, I got to see a piece of my work (I colored it and it was shot on my dragon, but not DP'ed or Directed by myself) on a projection screen not on the web were I was told it was going to live and now I seem to see noise everywhere.

 

[Stacey Spears]

Order of operations is something you should test.

For example. I would put noise reduction after scaling to delivery, or master, resolution. Scaling down is going to reduce some noise to begin with, so scale first, noise reduce (if you must) and then sharpen. You may do some creative sharpen at full res, but you should consider some sharpening after the final scale to compensate for softness introduced by scaling and noise reduction. While scaling is a must, noise reduction and sharpening are a very subjective thing. Be sure the display device you are using is not doing any of the three as well.

 

[Michael Tiemann]

Order of operations is something you should test.

For example. I would put noise reduction after scaling to delivery, or master, resolution. Scaling down is going to reduce some noise to begin with, so scale first, noise reduce (if you must) and then sharpen. You may do some creative sharpen at full res, but you should consider some sharpening after the final scale to compensate for softness introduced by scaling and noise reduction. While scaling is a must, noise reduction and sharpening are a very subjective thing. Be sure the display device you are using is not doing any of the three as well.

Well said! That should bubble up to REDUCATION.

 

[Marc Wielage]

Order of operations is something you should test. For example. I would put noise reduction after scaling to delivery, or master, resolution. Scaling down is going to reduce some noise to begin with, so scale first, noise reduce (if you must) and then sharpen. You may do some creative sharpen at full res, but you should consider some sharpening after the final scale to compensate for softness introduced by scaling and noise reduction. While scaling is a must, noise reduction and sharpening are a very subjective thing. Be sure the display device you are using is not doing any of the three as well.

That's a very good point. It's also computationally very difficult to do 4K noise reduction well. If you're only delivering HD, then it might make more sense to do the NR after the project is scaled down to 1080.

True, but...Resolve makes it easy to visualize the NR after applying a LUT or other image processing. And its NR allows you to apply NR to very specific parts of the image--be they shadow regions, colored regions, and/or regions that very specific spatial or temporal relationships. Resolve's extraordinary precision helps to ensure that small numbers in log space remain accurate numbers in more normal gamma space. You are absolutely right that our eyes can mislead us looking at RAW or (heaven forbid) linear light to make a NR decision. But we can still do the math where it works best for the image while evaluating it with a gamma that works best for us. At the end of the day, there are some kinds of noise you probably want to remove at the start of the imaging chain, and other kinds that are OK to deal with at the end.

In 30 years, I haven't found too many projects where I thought it was a good idea to remove the noise at the beginning of the chain. And I've dealt with about a dozen different kinds of noise reduction, temporal and spatial, dedicated boxes and processes, plus layers of different processes and parameters. The NR itself is going to react different based on contrast, and that's a prime reason why it would not work well to apply it to aun ungraded log signal prior to color correction.

Another thing you're not considering is the practicality of how involved it gets to do complex noise reduction, and how much time and money it takes to do. Often, there just aren't enough hours in the day to do really detailed, complex noise reduction. When I freelanced for Lowry Digital some years ago, I was surprised to find out that their process basically took about 10-12 hours to "cook" 20 minutes of files spread across about 200 simultaneous processors. The results were fantastic, and they had the ability to attack noise only in one or two color channels, affect highlights separately from lowlights, even apply sharpening to specific parts of the screen and not others. But it took many hours to set this up and lots of experience to make the decisions as to where and how to apply it. In some cases, the job had to be done multiple times to eliminate or minimize any artifacts. I know of some Lowry projects that literally took months of work, particularly when you factor in the restoration side (stabilization, rips, dirt, added grain, and so on).

Note that many kinds of grain reduction still introduce artifacts: for example, if you have a bright white candle in a black limbo area, in some cases remnants of the candle luminance outline will be seen in a cut to a different dark room. Stuff like this is difficult to predict, and for that reason you really need scene-to-scene control of how hard or how mild the noise reduction is applied.