Unidentified Brilliant Objects (UBO) 
appear at some brillant surfaces when used denoiser. If I don’t use denoiser, rendering takes too long.
What can I do to solve this problem?
NOT:
1- This problem only occurs video export option.
2- There is no problem in single renders, very clean result.
You could try to smooth it out with Topaz Video AI, I've had some success using that, but the jitter in your animation is pretty extreme and the AI model make take as long or longer to smooth it out as it would to just render with denoiser.
You could also try disabling DLSS, increase the reflection roughness, lower your light bounce count, increase your pixel detail count, or various combinations of all of these options. There is also a reflection distance option for non-path tracer, not sure if there is for PT, but if there is try decreasing that distance.
Hi,
Thanks for your reply. I will try your advices/solutions as soon as possible.
