UltraNR only denoising half of 4k footage

I find the UltraNR is great for denoising, but for 4k footage there is this weird bug where only half (sometimes a quarter?) of the footage is denoised properly, making the footage very unpleasant to watch.

I did some tests using a blank footage to showcase this effect. It's more apparent for certain values. And it generally affects luma, but not chroma.

All of these problems go away at 1080p.

Is anyone else experiencing the same issue?

Luma only (12.6) ultranr.jpg (736.92 KiB) Viewed 1392 times

Luma only (0.2) - ultranr.jpg (761.55 KiB) Viewed 1392 times

Chroma only (0.2) - ultranr.jpg (739.09 KiB) Viewed 1392 times

Interlacing?

Sorry I forgot to add context. This test is done by using a Nikon Z6. It's in H264 8 bit.

But the same issue also applies to other 4k videos, such as ones taken by a Nikon Z8 (4k/8k 10bit) and on my mobile phone.

Sorry I forgot to add context. This test is done by using a Nikon Z6. It's in H264 8 bit.

Which OS? What hardware? Which GPU drivers? What happens if you slow the render down?

What happens in HD -- does it work in this format?

Sorry I forgot to add context. This test is done by using a Nikon Z6. It's in H264 8 bit.

Which OS? What hardware? Which GPU drivers? What happens if you slow the render down?

What happens in HD -- does it work in this format?

Sorry I forgot to post these important details.

OS: Windows 11
CPU: 7950x3d
GPU: 4080 super, newest driver from Nvidia (this issue occurred when I had older drivers too)

It happens in the color page when doing the editing, as well as after it is rendered, even if I use slower presets.

It also happens if I export raw or H265 or DNXHR.

I also tried transcoding the source footage to other formats such as prores, DNXHR, and raw before importing back to resolve. But the same issue happens.

When I set the timeline resolution to HD, the issue disappears, and NR is applied to the whole video uniformly. Though it seems like I have to push the NR values higher to achieve similar level of NR.

YES. It is an known issue, it is flagged to BM and they where able to reproduce it with an Image I send a while ago...

YES. It is an known issue, it is flagged to BM and they where able to reproduce it with an Image I send a while ago...

Oh thanks a lot for your comment. This issue has been driving me mad for the past couple months. I spent so much effort testing different configurations before coming to this forum for help.

I have come up with a "workaround" which is to split the 4k image into 4 HD timelines. Do the NR on each of the file, then recombine them on a 4k timeline... There might be some artifacts on the edges but they don't seem noticeable.

It's a lot of effort, but to me, ultraNR does result in a better image compared to neat and topaz. I am not sure if others have the same experience.

Hopefully they can fix this issue as I think that ultraNR is great!

I have come up with a "workaround" which is to split the 4k image into 4 HD timelines. Do the NR on each of the file, then recombine them on a 4k timeline... There might be some artifacts on the edges but they don't seem noticeable.

It's a lot of effort, but to me, ultraNR does result in a better image compared to neat and topaz. I am not sure if others have the same experience.

Hopefully they can fix this issue as I think that ultraNR is great!

OK nevermind, this actually doesn't work, it results in the same kind of "banding" (?) that happened on a 4k timeline. Perhaps the problem with 4k is that they actually split it into 4x1080p sections to do the denoising?

Howdy

Sorry but is it related with half or quarter resolution chosen in playback preferences ?

Howdy

Sorry but is it related with half or quarter resolution chosen in playback preferences ?

Thanks for the suggestion, but it's already at full resolution.

It was not a suggestion actually, just a basic question, thx for answering...