sergisanchez wrote:The reasoning behind is the following: imagine you have a 90min feature film to grade, shot on an Alexa Mini. The film has been shot at ISO 800, with a few shots being underexposed. You want to denoise the 5% of shots underexposed, and then applying the noise pattern of the "correctly exposed" shots on top, to give an uniform look.
I don't think this is practical, for a lot of reasons. You're assuming the noise pattern will be identical in dozens (or hundreds) of subsequent shots, but it doesn't work that way. It's a lot more random.
I think a much more practical solution is just determine a reasonable amount of overall TNR and SNR -- even using different Lum and Chroma values -- to the entire image, without the complications of a layer mixer. We tend to do scene by scene (overall, not necessarily shot by shot) in the NR pass, but do tests just to make sure there's no artifacts. In truth, a lot of times a little noise is not going to hurt anything. The one possible exception would be (for example) a very glossy makeup commercial or a high-key food commercial. For those, we'd probably scrub every frame and make sure it's 100% clean. But for a feature, particularly one shot underexposed... I don't think a completely clean look is the right idea.
Neat Video is another solution that has a lot more user-adjustable parameters, but note that it's very demanding in terms of hardware and costs roughly 50% as much as Resolve.