Very problematic greenscreen - how to fix edges/halo?

Hi, guys,

This is the first time I came to such a problematic greenscreen source that I can’t key it properly to my (and my client’s) satisfaction, so I hope that some real pro(s) out there will help me with this or tell me what I am doing wrong or what should I do to fix it.

I prefer to do all my keying directly in Premiere Pro (Windows) but if this situation can only be fixed in After Effects I am all ears too, although the best would be to do it properly in Premiere.

I have 4K footage shot on a not very good greenscreen stage and I’m supposed to use the lector in parts of the composite video as full figure in “master” shots and only his upper half in “close ups”, where the keying problems are much more obvious.

The 15 sec sample of original 4k greenscreen footage I am working with is available to download here: https://www.dropbox.com/s/6kd81tbpdyosbv8/problematic%20greenscreen%20sample.mp4?dl=0

if anybody wants to try to do the magic :slight_smile:

Background I use for close up is here: https://www.dropbox.com/s/30ryluwmocedzxc/problematic%20greenscreen%20sample%20bg.png?dl=0

Even though the video source is 4k, the final project is 1080p. So, the problem is that not only the greenscreen stage is unevenly lit and has different color parts in it (especially the part where his legs are on the floor, see this pic: http://joxi.ru/v29n1W6HzWlw5A), but all his body has a distinct “halo” or edge, which I can not properly eliminate. For all of my keying I routinely use Premiere Pro’s Ultra Key which almost always gives a good result from the get go (in Agressive), but not in this case - see the pic: http://joxi.ru/n2YV1k3cZO6BMA). Paradoxically, the standard Ultra Key gives me much better result from the start than the supposedly much more superior and flexible Boris’ Primatte Studio, which gives me MUCH more halo before the matte tweaks: http://joxi.ru/8An9w6eS7VGQX2 . I have even tried Red Giant’s supposedly Hollywood quality keyer and it gives me even worse results than Boris.

So, after heavy tweaking I came to this result with Boris’ key: http://joxi.ru/gmv9wq4SvzbEXr
which is kinda ok for “masters” where the lector’s figure is relatively small, but very obvious for the close ups, for which I finally decided to use the heavily tweaked Ultra Key’s result, which is not ideal either, cause to eliminate the halo I have cranked up the matte’s transparency, among other things, see the pic: http://joxi.ru/n2YV1k3cZO6QMA
It introduces its own set of problems and is not looking good on light backgrounds which are also present in some places in the video and still there are some grey artifacts present, especially under his arms.

I’ve spent hours trying to solve this problem and watching tutorials and stuff, but still I can’t pull this problematic greenscreen off to a level of quality I want (i.e. no halo or visible greenscreen artifacts on the composite), yet Boris’ webinar tutorial on Primatte Studio (this one - https://www.youtube.com/watch?v=-FcfjqRTpYg&t=1519s) makes it seem like piece of cake supposedly on any, even problematic greenscreens.

So, any suggestions or maybe even direct solutions to my problem is welcome if anybody dealt with situation like this before. Thanks in advance!

Hello!

I’d be happy to take a look at this project for you and help you get the best possible key from this shot using BCC Primatte Studio. I’ll respond back asap with my results.

Cheers,
Peter.

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Hi,

Well that’s some pretty nasty footage - poor subject lighting, heavy compression and poor green screen setup. However, even with all that, I feel I’ve achieved a usable result with BCC Primatte Studio. I’ve done this in After Effects but you can achieve the exact same result in Premiere Pro using the preset that I provided for BCC Primatte Studio. I’ve attached a zip file to this message that contains an After Effects project and a Primatte Studio preset.

To remove the rigging, you need to use the integrated Mocha masking feature in Primatte Studio, or you could use the crop function - I used the integrated Outside Mask Crop function as it made the most sense for this particular shot.

Please note that the small white pixel cluster that sometimes appears near his underarm is actually in the original source shot, and is white in the shot, so you can’t remove that with this instance of the keyer. You should be able to fix that by patching it with an animated mask shape, most easily achieved via Mocha Pro.

I hope this helps.

Cheers, Peter.

SeregaKey.zip (17.2 KB)

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Yo, Peter!

Thanks for your quick reply and sample presets. I was surprised that you have used relatively low number of options available in Boris, just Spill Remover, Matte Refinement and Light Wrap Edge On, basically. But even though it looks better than what I have achieved myself, the halo is still present in Matte Status view - http://joxi.ru/brRpRlWcY1bqJ2

Thogh it is still better than what I’ve got :slight_smile: To eliminate unwanted portions of the image I usually use crop, as it is way more easier than tracking and allows you interactive quick tweaks if necessary. But I didn’t quite understand your suggestion of how to eliminate those pesky grey areas under his arms and in some other parts of his body - do you suggest to make a thin mask of these areas, track them in Mocha and then apply the dark grey color to those tracked parts? Did I understand you correct, cause I have never used such a technique before and generally trying to avoid tracking as much as possible :slight_smile:

You’re most welcome - I’m happy to help in whatever capacity that I can.

The halo that you see when viewing the Matte Status is intentional - what we see in this view are 3 shades : black, white and gray. We know that black represents 100% transparent pixels and that white represents 100% opaque pixels … the gray is showing us semi transparent pixels where there is a soft edge on the matte, which helps when compositing the shot over an alternate background source. It also helps when there is motion blur in the shot or for flyaway semi-transparent hair. Sorry if you already know that and I’m over explaining. :slight_smile: Just want to be sure that you know what this is and why I set it up like that.

If you would like to tighten up the matte, you can do so by adjusting the Matte Refinement parameters. For this shot, you can (1) increase the value in the Soften Matte parameter or (2) reduce the value in the Gamma parameter or (3) increase the value in the Choke parameter, or some combination thereof. You could also work with the Edge Correction group and adjust the brightness edge, contrast edge and gamma edge parameters to blend the edges better against the background plate.

For this shot, to eliminate the rigging, Crop is the best method. If the actor was moving in such a way that the Crop function was cutting into the foreground then you would use the Mocha option and generate an animated mask shape.

For the white pixels, I was indeed suggesting that you generate an animated mask shape and then filling the shape with pixels from the source. This can be done with Mocha or it could be done with the BCC Remover tool, but it’s going to take a little time to set that up. And yes, it would require tracking and keyframing, which is also done in Mocha. Given that it’s only 3 or 4 pixels in a massive 4k shot maybe it’s not something that the client would care enough about to pay you to fix it but if it must be fixed then I suggest using Mocha Pro.

Cheers,

Peter.

Thanks again for the detailed explanation, Peter, but may I ask you why you use AE instead of Premiere to pull off the key? Isn’t it easier to be in native host and do all the work within Premiere than switch back and forth for just the key? Does AE provide some better options for matte refinement or something?

Also, can you please suggest me a good (preferrable video) for BCC Removal (I have played with it but the results were far from perfect :)) or Mocha tracking for the purpose of my task so I can learn how to deal with such problems in future :slight_smile: Thanks in advance!

P.S. Also, can I use several instances of BCC Primatte for a video, like I routinely use Adobe’s native Ultra Key to apply to diffent parts of the image, or will it be too intensive on CPU?

You’re most welcome - I’m happy to provide you with any assistance that I can.

I tend to reach for AE over PP just because as a former compositor, it’s my tool of choice for this type of work. If I was an editor, I would most likely do all of this in the editing application of choice, which in this case would be Premiere Pro. The result should be the same regardless of the host application.

You can stack as many instances of the filter as needed to accomplish the task at hand. There are times when a shot has to be broken down and treated independently, for instance, one key for a persons hair, another for the torso etc etc. This practice is not uncommon.

We have many good videos that explain how to use the BCC Remover tool and how to use Mocha Pro. You can find them here :

https://borisfx.com/videos/continuum-2020-5-improved-remover-tool/

https://borisfx.com/videos/easily-remove-logo-with-mocha-pro-in-avid/

Or you can search through the trove of video tutorials that we have here :
https://borisfx.com/videos/

Cheers,
Peter.

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Thanks again, Peter, seems like I need to free some time to watch the videos you have suggested, and I’ll do :slight_smile: