HDRi Light Flicker & General Noise

[jate]

Alright, I'd really hoped to not add another post to the "Please help, grain everywhere and I'm a noob" list, but...

I have windows that the HDRi light is coming in through. That light is changing a lot from frame to frame (no good, since this is an animation):

Current Settings:

You'll instantly notice the 500 samples - this was lower because I was going to double the resolution and downscale to lower grain.

Result:

This was rendered at 2k, then resized to 1080p for noise reduction (it's obviously even smaller here).

Now this probably wouldn't even be that bad (I get closer to the glass, and there is glass on that table that I get close to in the next camera cut as well)...

But the next frame, the lighting completely shifts. It's inconsistent, even with Coherent Ratio turned up to .45 - when played with the other frames, it's very obvious that the lighting is changing, and it's as if there are fireworks or a turbulent noise light outside causing the light.

Does anyone have suggestions? I've been going through the forums, but it can be hard to pin down something like this.

Thank you!

[aoktar]

Give a change to "static noise". I found it helps to eliminate the flicker of coherent ratio in some scenarios. For noises, to try the different hdris or additional light sources can help.

[jate]

Thanks, I'll give static noise a go - I had a running bet with myself on what that actually did, but do you have an explanation?

*edit* I just checked the first 2 frames from the render only changing the "Static Noise", but the flickering seems to be much better now.
That's so weird, what does that check box actually do?

[jate]

It's also worth noting, 2 months later, I searched something like "Flicking Octane Reflection Glass Glossy Lights" because my noise was going away with minimal samples (pretty good around 700 samples or less even), and I was seeing lots of jitter in my glass textures only in the reflection of the lights, even at 3,000 or 5,000 sample animations (it'd go away at around 10,000 samples, but that's a huge jump from the 700 I needed to squash the noise).

My search ironically brought me back to my own post... and it even more ironically solved my issue again this time as well.

Conclusion, static noise doesn't even make my final frames noisy at all, it just keeps any flickering, either in any noise that gets left behind if I don't give it enough samples, or in noise reflections/flickering lights.

Aka - I'll pretty much be leaving Static Noise on as my default from here on out, especially when working with Pathtracing (currently my most used).