Question / Help Chroma key not functioning

Betapig

New Member
Hi, I'm starting to get into streaming, and wanted to get a chroma key screen, so i bought a black one off of amazon (I know, not the best idea, but figured it would be better than nothing) but when i go to set up the chromakey filter in OBS, the presets work fine, and makes some of the stuff in my room, along with my hair, transparent, but the second i choose custom and pick the color off my screen, the entire screen just goes gray, not fuzz, no movement, just still gray. I've tried changing the lighting, nothing. I've even tried setting my smart bulbs to 100% and pointing my webcam directly into the light, nothing. Before i even got my screen it did this when i was messing around with it to figure everything out. The defaults worked fine. Yet the second i did a custom color it does this every time.

Do any of you know how to fix this? Is there a specific thing my webcam needs to have in order to use chroma key? Do I need to get a different screen?

Images: https://imgur.com/gallery/f0ep0aC
 

carlmmii

Active Member
Chroma key is not going to work well with a black background. By definition, chroma keys need color to work effectively. Black has no chroma value -- it's just a light intensity. The only thing you're going to be able to do is make dark areas transparent, and have a lot of bleed into greys because they match the zero-chroma value of black.

The best you can do without changing your screen is to use the Color Key filer, use pure black (#000000) as your color, and adjust as much as you can from there.

The real fix is to get an actual green screen.
 

Betapig

New Member
Chroma key is not going to work well with a black background. By definition, chroma keys need color to work effectively. Black has no chroma value -- it's just a light intensity. The only thing you're going to be able to do is make dark areas transparent.

The best you can do without changing your screen is to use the Color Key filer, use pure black (#000000) as your color, and adjust as much as you can from there.

The real fix is to get an actual green screen.
I understand what you're saying and that's why i said "(I know, not the best idea, but figured it would be better than nothing) "

But it does this with any chromakey setting that isnt a preset. If I even touch custom it does this. Like, i have my laptop out off of my desk where my chromakey screen is, so it's seeing my white wall and red bed, and its just a 100% black screen on the preview

Edit for clarification: This is with only the webcam being on the scene. Nothing else
 
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carlmmii

Active Member
When setting a custom color, you need to be very careful with the tuning. As soon as you choose a color with more than one primary color (i.e. a color that isn't pure red, green, or blue), then you're going to be matching a much wider range of colors according to the algorithm. This means the similarity setting has to be turned way down.

Turning the similarity down to 1 and the smoothness down to 1 should at least give you some kind of image left over though. Does this happen on your end?
 

KevinEdens

New Member
I have a similar problem but I'm using a green screen. What I have noticed is that if I use a color key filter instead of a chromakey filter... it works fine except that the color key doesn't have key color spill reduction which is really nice. When I click custom color with a chromakey filter and adjust the similarity everything but the green screen disappears. I just got a new laptop and this didn't happen on the old laptop. I'm wondering if it might be a version of a library (ffmpeg etc) that I have installed.
 
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