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Keylight Hair Noise

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Tamer Aswad
Keylight Hair Noise
on Jul 31, 2016 at 3:07:29 pm

I know this might have been addressed before on this forum, but i read most of the threads , and none of the solutions helped me, If anyone can let me know what is the best way to fix this problem let me know , thank you ..

here's a snapshot of the video

https://vimeo.com/176931391

Password: cow


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Kalle Kannisto
Re: Keylight Hair Noise
on Jul 31, 2016 at 5:50:28 pm

What solutions did you already try?

Have you tried temporal noise reduction?


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Tamer Aswad
Re: Keylight Hair Noise
on Jul 31, 2016 at 5:56:26 pm

I did try that , didn't work out well, and it's not a one time problem, I produce a lot of online videos, but they mostly have the same issue on different levels..


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Kalle Kannisto
Re: Keylight Hair Noise
on Aug 1, 2016 at 6:57:55 am

Then it might go back to what camera and format you are using to shoot the footage. And there's plenty that can go wrong at earlier stages of the production particularly in the lighting department. But the issue doesn't look that bad to me, all I see a fast jitter that shouldn't be there. I wonder if you could fix that with Deflicker as a post-key effect.


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Kalle Kannisto
Re: Keylight Hair Noise
on Aug 1, 2016 at 7:19:30 am

I thought it so I tried it. It does calm the edges down considerably. See what you think.

10356_testdeflicker1080pmbr.mp4.zip


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Tamer Aswad
Re: Keylight Hair Noise
on Aug 1, 2016 at 9:59:47 am

thanks :) yea I guess it helped a little bit, I know it's not much of a noise, as more of a flickering on the edges, but I want to get rid of them for good, that's why i want to know the source of my problem, and it's aching my head


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Tamer Aswad
Re: Keylight Hair Noise
on Aug 1, 2016 at 10:06:56 am

I also tried the remove grain effect, and I manually sampled the boxes, but after I add this effect, it helped but it takes so much time to render! so much !


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Tamer Aswad
Re: Keylight Hair Noise
on Aug 1, 2016 at 9:58:41 am

yes i am still using Low budget cameras, but they are working fine. because I have good lighting, but the only thing missing is a back light or a head light in a three point lighting, so i have only the key 800w and the fill light, and two kinos for my green screen...


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Kalle Kannisto
Re: Keylight Hair Noise
on Aug 1, 2016 at 1:07:00 pm
Last Edited By Kalle Kannisto on Aug 1, 2016 at 1:10:06 pm

Then I'm fairly certain it is the camera's compression and/or sharpening method that causes the issue. For instance, some cameras that are both still and video read every third row for the video so small details like hair simply disappear and reappear depending on whether they hit the "video" pixel row or not. But I've had good results with temporal noise reduction (applied before keylight) when shooting with 8-bit compressed formats. It does slow things down massively, so running it on long pieces of footage is far from ideal. Best cure for more expedient a workflow is to get a camera that can shoot Prores HQ or RAW, if you ask me.

Other options for handling without additional expense exist, among them:

- A different background (darker in this case) against which the flickering is not as obvious
- Minimizing the flyaways in the hair of the talent -- before shooting, that is
- Blowing the flyaways out with a more aggressive key as opposed to trying to capture every hair. You see this all the time even in high-end productions. Although it may look bad to the trained eye, the general audience probably won't notice a thing. And it is definitely less distracting than flickering edges.


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Tamer Aswad
Re: Keylight Hair Noise
on Aug 1, 2016 at 2:08:00 pm

that's some valuable information here, thanks a lot for your time, especially that It took me a lot of time to find something on the internet about this matter, maybe since I have a trained eye now, and since we all videographers have a perfectionism problem :) I am currently using DSLR cameras, which i am sure they are highly compressed, and with a color profile 4:4:1.

may i ask for a couple camera/camcorders suggestions which has 4:4:2 color profile or Prores HQ? which aren't massively expensive, I heard the black magic cinema pocket camera records in 4:4:2 and Prores, would you recommend it for Green Chroma? knowing that my video production is basically music education videos, not a lot of movement.

I will certainly try one of the points you gave which can handle the flickering edges, or make them less obvious.


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Dave LaRonde
Re: Keylight Hair Noise
on Aug 1, 2016 at 2:16:58 pm
Last Edited By Dave LaRonde on Aug 1, 2016 at 2:28:55 pm

Sorry, but I'm unable to see the example on my phone for some reason. When a key is bad I look at the lighting first and then the camera.
If you aren't lighting the subject separately from the background, you open yourself to problems. You have no ability to make the background lighting flat and featureless, and you can't control the intensity of the background lightind. Since Keylight seems to perform better on a darker than expected background, this can be an issue.
Then when I read the term, "budget camera", I automatically think, "bad key". Such cameras take shortcuts when. encoding the video signal, and it's almost always at the expense of the color component. The colors aren't as sharply-defined as the lumnance component. Since chroma keying is all about the edges, what do you need for a good key? Well-defined color edges, which budget cameras lack. Increasing the sharpness on such cameras ony makes the problem worse. It does NOT improve the accuracy of the color.

You can also sidestep the issue by taking care that the subject doesn't have wispy, fly-away hair... in other words, a makeup artist can be a very good investment.

Dave LaRonde
Promotion Producer
KGAN (CBS) & KFXA (Fox) Cedar Rapids, IA


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Tamer Aswad
Re: Keylight Hair Noise
on Aug 1, 2016 at 2:41:49 pm

Hi Dave, I have managed to pull a good key, but my only problem is with the noise I get on the edges, and I thought there some way to go behind it without buying a high budget camera, i'm working in a startup company in Jordan, we produce music online courses, but I can't yet afford a high budget camcorder, at the moment I am using a three point lighting, the only thing I am missing is a back light to light the presenter from the back, the rest of my lighting is good, and I was wondering if a back light would change the whole noise thing, I know now it's also an issue with the camera as well, as high compressed videos that shoot lower than 4:4:2 color profile can have this issue with green chroma


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Stephen Smith
Re: Keylight Hair Noise
on Aug 1, 2016 at 3:21:44 pm

The best way to remove noise from the edge of a keyed clip is to use the "Key Cleaner" filter. It is amazing but takes forever to do a RAM preview with.

Stephen Smith

Utah Video Productions

Check out my Vimeo page


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Dave LaRonde
Re: Keylight Hair Noise
on Aug 1, 2016 at 4:03:40 pm

I have always had good luck chroma keying using a very OLD camera -- a Panasonic HVX 100. No kidding. With good lighting, I find it produces a very nice chroma key.

The reason: its DVCProHD codec encodes using 4:2:2 color sampling (aka color resolution). Compared to a DSLR's 4:2:0 or 4:1:1 color sampling, the color component is twice as detailed.

I wouldn't be surprised to learn that such a camera could be obtained at a bargain-basement price.

Dave LaRonde
Promotion Producer
KGAN (CBS) & KFXA (Fox) Cedar Rapids, IA


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Walter Soyka
Re: Keylight Hair Noise
on Aug 1, 2016 at 5:32:22 pm

[Tamer Aswad] "I have managed to pull a good key, but my only problem is with the noise I get on the edges"

Eliminating "noise on the edges" is what differentiates a good key from a bad one.

Sometimes it's necessary to comp the output of multiple keyers together for the best results.

Walter Soyka
Designer & Mad Scientist at Keen Live [link]
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
@keenlive [twitter]   |   RenderBreak [blog]   |   Profile [LinkedIn]


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Tamer Aswad
Re: Keylight Hair Noise
on Aug 2, 2016 at 9:39:41 am

Hi Walter , yes that's true, hence I asked what may be the source of my problem, it looks like it's color sampling, as i use dslr cameras, which has 4:4:0 color sampling, I guess I have to invest in a a camcorder that records on 4:4:2


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Stephen Smith
Re: Keylight Hair Noise
on Aug 2, 2016 at 3:02:53 pm

A better camera is never a bad thing. However, I've keyed plenty of DSLR footage with out any problems. A good light set up goes a long way.

For your situation use the Key Cleaner, last time I used it these settings worked best for me:

Additional Edge Radius: 1.6
Reduce Chatter: Checked
Alpha Contrast: 0%
Strength: 100%

Stephen Smith

Utah Video Productions

Check out my Vimeo page


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Tamer Aswad
Re: Keylight Hair Noise
on Aug 2, 2016 at 3:58:40 pm

That's great to hear, thank you , I will certainly try the key cleaner as you mentioned, thanks for your time :)


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