video gets darker after denoising

questions about practical use of Neat Video, examples of use
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21stcj
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Joined: Tue Mar 23, 2010 3:30 pm

video gets darker after denoising

Post by 21stcj » Tue Mar 23, 2010 3:40 pm

hey
i've denoised a lot of mp4 and m2t footage recently (via virtualdub and avisynth), and the output version has not only lost noise but also brightness.

http://www.henrikbauer.com/neat-unprocessed.bmp

http://www.henrikbauer.com/neat-processed.bmp

i guess a bit of brightness gets lost because the dirt has been removed, but i'm sceptical if theres also some lost in the process.

NVTeam
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Post by NVTeam » Tue Mar 23, 2010 5:25 pm

> via virtualdub and avisynth

Perhaps there was something more than just noise reduction in that workflow?

Vlad
Image Image Neat Video team
noise reduction for video and photos

21stcj
Posts: 4
Joined: Tue Mar 23, 2010 3:30 pm

Post by 21stcj » Tue Mar 23, 2010 7:08 pm

no, nothing like brightness adjustments anywhere.
camera films dv avi, m2t or mp4 file.
import to vdub via avs, just 'directshowsource' and no extras
denoise to lagarith compressed avi video

then i imported the denoised and the source video files to vegas and had the result as seen in the pics.
i know that by removing the noise the video gets a bit darker cause the noise is bright by itself. but i got the impression that nv takes more away than it needs to. some areas are really getting too dark when denoised.

NVTeam
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Post by NVTeam » Tue Mar 23, 2010 7:52 pm

NV itself does not modify the brightness of the image. It must be something else in that workflow in virtualdub and avisynth.

Please try the NV plug-in for Vegas, to see how it affects the original clip. You will see that the noise is reduced but brightness/contrast remain the same.

Thank you,
Vlad
Image Image Neat Video team
noise reduction for video and photos

21stcj
Posts: 4
Joined: Tue Mar 23, 2010 3:30 pm

Post by 21stcj » Tue Mar 23, 2010 10:51 pm

it doesnt affect the brightness, but it does affect the brightness...

like i said, it affects the brightness of the noisy parts of the video by removing the noise. maybe i just need to live with it, or raise the gamma value in the brightness plugin after denoising it. however its been something that confused me all the time, so i thought i'd mention it on this forum.

i wont switch away from virtualdub, cause you can lower vdubs priority. imagine denoising stuff for a month without being able to lower the cpu usage (like in vegas). i wouldnt be able to do anything else on the comp for the duration of the denoising, so i would need a second computer, one for denoising and one for editing.
thats why i love virtualdub for what it is.

NVTeam
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Post by NVTeam » Tue Mar 23, 2010 11:05 pm

Why not just make a small test, to see whether the Vegas version of Neat Video will change the brightness of your original clip or not? Just in Vegas preview. I think it will not change it. I also think that VirtualDub and Neat Video alone will also not change it (in those noisy parts as well). If you can reproduce brightness change using either Vegas+Neat Video for Vegas, or VirtualDub+Neat Video for VirtualDub, please send me a test project allowing to reproduce the effect.

Thank you,
Vlad
Image Image Neat Video team
noise reduction for video and photos

rsh
Posts: 2
Joined: Fri Apr 14, 2017 2:51 pm

Post by rsh » Fri Apr 14, 2017 3:29 pm

21stcj, I realise this is a very old thread but when typing in "neat video darker" in a google search, this thread is about the only thing that comes up on the topic... and I have a workaround for your situation.

I was at the end of a project and we filmed a few scenes in low light, so I started using Neat Video to reduce the noise for certain clips. Everything was fine until I saw a clip lose a lot of brightness. This puzzled me because it didn't happen to the other clips. Eventually I worked out that clips being linked to After Effects didn't have the dark issue.

So, I tried simply right-clicking on the problem clip, selected "Replace with After Effects Composition" and then dragged the Neat Video plugin over that on the timeline and, hey presto, no darkening issue.

I hope this helps... seven years too late lol.

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