Flicker removal strategies?

[bendingpixels]

Hi All, trying to get my head around this. In the attached renders, the first is done using a .6 coherent ratio. and as promised in tutorial video it generated tremendous flicker. I then reduced the flicker over several renders to see where it would disappear and I got down to .2 -and as promised the flicker is "mostly gone", but the render time went thru the roof. Is coherent ratio the right approach? and should I just learn to live with that super long render for animations? I haven't really found a good explination of what that even is, but it definitely seems to make the flicker go away, but at great cost.

thanks!
rob

laptop-pt6-coherent-vimeo.mp4

Point 6 Coherent ratio with lots of flicker

(2.01 MiB) Downloaded 4251 times

laptop-pt6-coherent-vimeo.mp4

Point 6 Coherent ratio with lots of flicker

(2.01 MiB) Downloaded 4251 times

[abstrax]

You could try enabling the option "static noise" or just calculate more samples.

[tomabobu]

From my limited experience I can say that I try to stay away from "Coherent ratio" when I render animations so I always leave it to 0. If you render a still it's very helpful but other than that it's useless in my opinion.

[bepeg4d]

Hi,
in my experience, the coherent ratio value goes in conjunction with the number of sampling, the more high the sampling is, the more high coherent ratio value you can use
How many sampling you have currently?
ciao beppe

[Ron]

From my limited experience I can say that I try to stay away from "Coherent ratio" when I render animations so I always leave it to 0. If you render a still it's very helpful but other than that it's useless in my opinion.

I agree with this. I never use "coherent ratio" with animations because this simply leads to flickering results regardless of any settings.
Had too many crappy animations in the beginning so i decided to keep it zeroed out.

[bendingpixels]

Hey guys, thanks for the replies...

The Sample rate is at 4096 on both renders. I'm going to fire off a render with 0 coherent ratio and double the sample rate and see what happens. If I"m understanding correctly, the render time should go up and the flicker should go away and the noise should go away too?

thanks again!
rob

[Ron]

I would assume that flickering goes away without cranking up the sample rate. So you can keep render times quite the same.
Other for noise level. This is depending on sample rate. But 4096 samples is pretty high. I never use such high values. Have you tweaked the "Hot Pixel"l value?

[bendingpixels]

Hi Ron, I just stopped that render and went back to 4096 at 0 coherent. The render time at more than 8K samples was going to be too long anyway.

I haven't messed with the Hotpixel because I didn't see any hot pixels. But does that setting help with noise even when there's no visible hotpixels?

[Ron]

I tend to decrease the hot pixel value to around 0.7 in any render i do. It does not necessarily help to reduce noise but does cost no extra fee - so if hot pixels would have been around I eliminate them before.
With animations I tend to bring the renders to an acceptable amount of noise and remove that with the NeatVideo-Plugin in After Effects. This is - in most times - way faster to get good results as to mess around with high sample rates and extra-long render times.

[bendingpixels]

Wow, I hadn't thought of that. I have Neat Video and use it for live action stuff all the time. Have you tried multiple pass compositing with that? or do you only use it on renders where the full shot happens in the picture viewer?