Using NV with Virtualdub - ruins carpet or grass in scenes

questions about practical use of Neat Video, examples of use
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lschafroth
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Joined: Sun Dec 21, 2008 3:56 am

Using NV with Virtualdub - ruins carpet or grass in scenes

Post by lschafroth » Sun Dec 21, 2008 3:59 am

I'm using NV to clean up 8mm footage I have shot with a DV camera and a projection box I have built. It isnt the best quality but pretty darn good.

NV cleans up the footage wonderfully, except when a scene has grass or carpet. It blurs it all into a mush.

How can I configure NV to deal with details such as grass and carpet? The other footage in the scene like walls and etc, badly need the filtering but the blurred mess of the carpet ruins the scene.

What would be the best method to build a profile for this footage?

Lannie

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Post by NVTeam » Sun Dec 21, 2008 12:46 pm

The best way to avoid blurring of details is to build an accurate noise profile for the scenes where you see blurring. Blurring usually means the used noise profile is not right for this scene. Try to build a new one specifically for this scene.

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

lschafroth
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Joined: Sun Dec 21, 2008 3:56 am

Post by lschafroth » Mon Dec 22, 2008 1:47 am

Should I build a profile using the Neatimage profile and the same camera I used for the footage or do the automatic profile for each scene?

Lannie

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Post by NVTeam » Mon Dec 22, 2008 8:43 am

I recommend to build a new profile for each scene. Please check the user guide how you can use Auto Profile to build an accurate profile.

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

lschafroth
Posts: 8
Joined: Sun Dec 21, 2008 3:56 am

Post by lschafroth » Wed Dec 24, 2008 10:21 pm

The probolem is, you cannot build a profile. There is not a single frame that the profile works. It always says it cannot find a large uniform area.

Since it is gravel, grass or carpet, it comes out a blurred mess.

Lannie

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Post by NVTeam » Wed Dec 24, 2008 10:42 pm

You can try to build a profile using another clip shot in the same conditions. A clip that includes some areas suitable for profiling, like a flat wall.

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

lschafroth
Posts: 8
Joined: Sun Dec 21, 2008 3:56 am

Post by lschafroth » Wed Dec 24, 2008 11:29 pm

that contradicts your instructions from earlier. If I use the profile from a different scene, then the carpet or grass is blurred out.

To keep that from happening you say I have to profile from that scene which is refuses to do so.

Lannie

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Post by NVTeam » Wed Dec 24, 2008 11:45 pm

An alternative video should be from the same device, shot in the same device mode. In this case, the noise in the video will be the same and a profile built using such an alternative video will be good for the video with carpet. Of course, if you use a completely unrelated video produced by different camera or in different camera mode then the resulting profile will not be anywhere close to accurate for the carpet video, because noise in that alternative video and in your working video will be very different.

To avoid blurring, you need an accurate profile for the noise present in your working video. You either have to find (and manually select) a small uniform area in the working video itself, or use an alternative video that has the same noise (which is usually the case if it is produced by the same device in the save device mode).

In any case, if you get a warning from NV after clicking Auto Profile, try to manually select an area for profiling (it can be as small as 32x32 pixels but the larger the better) and repeat Auto Profile. It is okay to use a small area, but it is not good to use area with details.

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

lschafroth
Posts: 8
Joined: Sun Dec 21, 2008 3:56 am

Post by lschafroth » Wed Dec 24, 2008 11:48 pm

I didnt see where I can do the smaller area selection. Once it's finished processing the scene it's on now I will try and find that and see how it works.

Thanks!

Lannie

lschafroth
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Joined: Sun Dec 21, 2008 3:56 am

Post by lschafroth » Sun Dec 28, 2008 7:15 pm

Any of my scenes with mountains in the background are smoothed and and very blotchy so I cannot use NV on these scenes.

I have messed with all the settings for hours with no success.

Lannie

PS I have been able to do scenes with grass and trees and it looks pretty good, but the distance mountain scenes simply cant be filtered with NV.

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Post by NVTeam » Sun Dec 28, 2008 7:26 pm

Everything can be filtered but you need to find a way to build an accurate noise profile in each case. If you get bad results than means the profile you use is inaccurate or not corresponding the noise properties of specific scene.

Or you can just disable filtration in the intra-frame filter and use only temporal filter that can help on its own as well.

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

lschafroth
Posts: 8
Joined: Sun Dec 21, 2008 3:56 am

Post by lschafroth » Mon Dec 29, 2008 5:04 pm

I'm currently using 2.0 for virtualdub. Should I upgrade to 2.22?

Is there that much of a difference?

Lannie

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Post by NVTeam » Mon Dec 29, 2008 5:10 pm

I don't see any reason not to update. It won't hurt in any case, and it may be better in some cases.

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

lschafroth
Posts: 8
Joined: Sun Dec 21, 2008 3:56 am

Post by lschafroth » Wed Dec 31, 2008 2:56 am

I found NV 2.0 will process the video MUCH better if I do not seperate the interlaced fields before filtering. I just leave it as is and the filtering is better and it was able to build a better profile without seperating the fields.

It took me 74 frames, 1 test at a time to find a profile above 75%. I was able to build a 86% profile and the results are MUCH, MUCH better!

Thank you!!

Lannie

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