Hi, all. I'm having trouble getting my green screen to key out and I'm getting a crazy pixelated edge on my subject. I've had pretty good luck using Keylight in the past, but I've always been able to get good results by adjusting the Screen Gain and Screen Balance. The other parameters are a bit of a mystery, so I'm not sure which settings to adjust to fix the key. So far, any sliders I touch only seem to make it worse. Can anyone suggest a fix? My thanks in advance for any advice. My settings and the crappy result below ...
I've always been able to get good results by adjusting the Screen Gain and Screen Balance. The other parameters are a bit of a mystery...
It's time to de-mystify them. Keylight does a lot, but it's not the most intuitive effect to use. Because lighting conditions, camera settings, color sampling, and capture codecs all differ, there can be no "just do this" type of keylight recipe... and it seems like you're seeking one. The various views in Keylight are extremely valuable, especially the Status view.
I'd begin by going to the people who designed Keylight. Go to the The Foundry website, and download the Keylight tutorial materials there. I also know of tutorial material on the Creative COW:
...and you could also check the Videocopilot web site.
Briefly, the status view shows the quality of the matte used by the chroma key: Black is transparent, white is opaque, and gray is meant for the edges. Green indicates lack of spill suppression. By using the Clip Black and Clip White controls, you can lose a lot extraneous key background, and firm up the core. Don't forget that animated garbage masks can be your friends.
If they key wasn't lit properly, there's the danger that the image will have noise in it. If that happens, use the key you've already pulled as an alpha matte for a duplicated layer of the footage.