banding with dimming lights

questions about practical use of Neat Video, examples of use
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epi
Posts: 5
Joined: Sun Jul 12, 2009 5:21 am

banding with dimming lights

Post by epi »

Didn't know how to explain it better.

Hi,

I'm a registered user of Neat Video and this is my first project. So yes, I'm a newbie. I'm very happy with the way nv gets rid of the grains and artifacts (even some compression artifatcs) but it creates some sort of color banding around/in dimming/fading lights and no matter what I do, I can't get rid of it.

Here's a clip with neat video (compressed wt cinepak):
http://www.matonline.net/neat/neat_vid.avi

Here's the clip without neat video (again compressed wt cinepak):
http://www.matonline.net/neat/original.avi

I've tried different temporal filter settings hoping that they might help but didn't have any luck. I've also tried increasing color depth to 16-bit per channel but that didn't help either.

Any suggestions?
NVTeam
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Post by NVTeam »

Hi, I have extracted one frame from the original clip, please take a look: frame.

I have highlighted the areas with visible banding. Do you mean those areas and that kind of banding?

Please note that the above frame is from the original clip. Which means the problem is already present in the original clip (it may be somewhat hidden by the noise).

I would try to compress the original using another codec to avoid that banding.

Hope this helps,
Vlad
epi
Posts: 5
Joined: Sun Jul 12, 2009 5:21 am

Post by epi »

I guess banding is not the term I should be using but I didn't know what to call it. The problem isn't the banding you point out that exist in single frames but an inter-frame effect that is visible when you watch the video. Not just around the light sources but in and especially around the beams of light, as they are fading in and out.

I'm just using the cinepak compression for uploading the files here, normally I check the output uncompressed.

I think part of the problem might be due to misinterpretation of color space of the original video by AE which resulted in nv trying to internally convert something that was already in YCbCr. Could it be the case?

(BTW, thanks for the quick reply :) )
NVTeam
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Post by NVTeam »

When I watch the video I can only see the banding that I have pointed out above. It is visible in original clip in both static frames and during playback.

Could you clarify what and where do you see? Please show it using some still frames (saved in high quality JPEG) or make a visible selection in the affected area in the clip. Please save both original and filtered clip using high quality compression like 10mbit xvid and check that you still see the effect in the compressed clips.

Thank you,
Vlad
epi
Posts: 5
Joined: Sun Jul 12, 2009 5:21 am

Post by epi »

http://www.matonline.net/neat/nv_test.zip
A very quick switch between those three frames gives me the same effect. I'm startin' to think it has to do with ghosting on my lcd :?
NVTeam
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Post by NVTeam »

I cannot see any issues in the areas you have highlighted. I have checked on two different computers.

Vlad
epi
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Joined: Sun Jul 12, 2009 5:21 am

Post by epi »

Static frames look perfect but color changes between frames in selected areas seem tougher to me then in unprocessed video and to my eyes it creates a banding like effect during playback, that's the best way I can describe it. But maybe it is just a ghosting effect on my monitor.

Thanks for your help.
NVTeam
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Post by NVTeam »

Please check whether you can see the effect on another monitor and let me know.

Thank you,
Vlad
Lugarimo
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Post by Lugarimo »

epi, I think it your lcd monitor. When my towns computer shop stopped selling CRT screens I noticed LCD was lower quality, had color bands like you described etc. Maybe you also notice on CRT but that is because without the noise you notice things you wouldnt otherwise. You should just compress it with a codec like Vlad suggest, maybe xvid fix it if you compress a little more.
epi
Posts: 5
Joined: Sun Jul 12, 2009 5:21 am

Post by epi »

I used to think I could trust my lcd monitor, its a PVA panel, 16.7M colors, 6ms Samsung 971p, one of the best options I had. And I export the video uncompressed, with the best settings I can, as in the static frames I uploaded, so I don't think compression was my issue.

Anyway, I tweaked my settings a little and it looks better now. Checked it on a lcd tv, I can still see the problem but very less then before and overall it looks nice. That "without the noise you notice things you wouldnt otherwise" argument makes most sense to me. I'll also check it with an old school crt tv.

That aside, I gotta say, Neat video + Magic Bullet Looks is a hell of a combination. I'm very happy with the results.

I got a newbie question regarding this. Neat video supports 16bpc, Magic Bullet Looks supports 32bpc, so can I use them in a project set at 32bpc, Neat Video first, Magic Bullet Looks second in chain? Or should I leave it at 16bpc?
NVTeam
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Post by NVTeam »

One of our monitors is also 971p so it is strange that we cannot see the problem directly.

Regarding the bitdepth, both options can be used: in any case, Neat Video will apply its filtration to 16bpc data. So, I expect the results to be the same if you use 16bpc or 32bpc setting in the project.

Vlad
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