This is Dithering for the Sobol sampler, it could be something kind of "easy" to implement (please keep in mind that I use the "easy" term very carefully because I'm not sure if it's actually "easy") but it can benefit A LOT the render results and it could help A LOT also with denoising quality.
I will present here an example, in this case and for the shake of making the effect more visible I will be also using Scramble Distance in Cycles, but the effects of dithering are good without scrambel too.
Here I present two pictures, the first one is the standard Sobol pattern of cycles at 500 samples:
The second one is the exact same scene with the exact same amount of samples, just that it renders 3 seconds faster and delivers a far better quality under the same amount of samples:
Now the better sobol pattern ends up giving less visible noise (or subjective noise) and a far better picture to look at.
Also the denoiser behaves way better, here is the example (There is a bit JPG compression):
Here are both denoised pictures:
NO Dither version:
DIther version:
Regarding the technical side of things here is a paper from Solid Angle about this, I think this is the one used in Cycles:
https://www.arnoldrenderer.com/research ... stract.pdf
And also here is the patch from Lukas Stockner with the implementation in Cycles, it may be useful since I read in the wiki the sobol implementation is coming from the Cycles Sobol implementation

(OK, I'll post the patch later, it seems blender.org is under DoS attack for some reason :S )
I hope you see the benefits, and what it's more important, I hope it's easy to implement and we can get big improvement with low effort
