Square artifacts on the upper-left corner

resolve technical issues related to use of Neat Video
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XPerienceD
Posts: 3
Joined: Thu May 22, 2014 2:32 am

Square artifacts on the upper-left corner

Post by XPerienceD »

Dear Neat Video-Team,

A few days ago I have purchased the Home Edition of Neat Video for the purpose of noise removal on my digitalized VHS/S-VHS videos using VirtualDub.

While this filter does an outstanding job removing noise, I have encountered occasions where I had blocking artifacts on the upper-left corner that lasted one or two frames. Most of the time the video stays artifact-free, but occasionally I see a squared area containing remains from the previous frame.

I have linked an animated GIF-file to illustrate the problem here:
http://i60.tinypic.com/mhskk1.gif

This problem seems to occur randomly and is not always reproducible. If I filter an identical scene again, the artifacts usually don't occur again - but they might appear at other scenes.

I am not sure if this problem is related to an issue addressed in an older thread: "Left edge black border causes improper filtration"
http://www.neatvideo.com/nvforum/viewtopic.php?t=734

If you look at the GIF file, you will see that there is a black border on the left edge as well, so I wonder if that might be the cause.

I can visually inspect whole video files to spot the artifacts and refilter parts from the original file, but it is time consuming and it would be better to have the confidence that the artifacts don't occur, ever though they are few in numbers.

Has anyone else experienced the problem and came up with a solution?
NVTeam
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Joined: Thu Sep 01, 2005 4:12 pm
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Post by NVTeam »

Please let me see the Performance settings in Neat Video Preferences on your computer. My guess is that the problem might be related to GPU processing.

Please also check the version of the video driver.

I do not think the problem is related to that old (and already fixed) issue described in the other thread.

Thank you,
Vlad
XPerienceD
Posts: 3
Joined: Thu May 22, 2014 2:32 am

Post by XPerienceD »

Hello NVTeam,

Thank you for your response. Since I have selected the option to use both CPU and GPU for processing, I wondered whether it could occur that the CPU and GPU get sort of "out of sync" for a fraction of second, thus producing the artifacts.

Let me provide screenshots of my NV settings and some information about my PC:

AMD Athlon X2 3.6 GHz
4GB RAM
Windows 7 Ultimate 64bit OS
GPU NVidia Geforce GT 430 (1GB RAM) (Driver 335.23)

Image

Image

Image

I will try to run NV using CPU only - maybe that will help. The slight speed penalty is not a big issue for me.
NVTeam
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Joined: Thu Sep 01, 2005 4:12 pm
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Post by NVTeam »

Thank you for the screenshots.

Please try to render using the CPU only.

Please also try to disable Adaptive Filtration setting (it should better be used only when necessary, not just all the time) for a test.

Thank you,
Vlad
XPerienceD
Posts: 3
Joined: Thu May 22, 2014 2:32 am

Post by XPerienceD »

I can report that switching the processing mode to CPU only and disabling Adaptive Filtration has fixed the artifacts problem. I don't know in what way each setting contributed to the artifacts, but I am happy that they do no longer show up.

Speaking about Adaptive Filtration, you mentioned that it should not be used just all the time. I actually thought there would be nothing wrong with having it activated all the time, since a lot of videos have low-light scenes that are noisier than outdoor scenes. It was my understanding that the adaptive filtration mode would accommodate different noise levels - or am I looking at it the wrong way?
NVTeam
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Joined: Thu Sep 01, 2005 4:12 pm
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Post by NVTeam »

Please check which one setting is triggering the problem: the CPU-only mode or Adaptive Filtration.

Adaptive Filtration should only be used when noise is actually changing within the clip. It is the same across the whole timeline of the clip then it is better (from the standpoint of stability of noise reduction results) to keep it disabled. If that option was universally positive in all imaginable cases then we would just enable it and not make it an user-adjustable option to begin with. So it is best to use it responsibly. :-)

Vlad
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