-
having trouble with Sony Vegas 9 Pro chroma keyer
I just can’t seem to totally key out the blue background (BTW, I used blue because my subject is predominantly green in color). I am left with some halo around the subject, especially toward the bottom where front light wasn’t quite as good. I’m not sure how to add multiple keys in Vegas without them affecting the prior keys and I’m also not sure if Vegas has the equivalent of spill suppressor or matte choker, these last two tools of which would really help me I think. Any ideas would be appreciated here. I came across one tutorial on multiple keying using the opposite of the background key (red instead of blue), but I wasn’t able to understand the method.
Thanks,
Jon -
3 Replies
-
Blue isn’t a good color to key because video doesn’t contain as many samples of it as it does green (which is carried on the luminance channel). That’s why we use green for video but I understand that you couldn’t in this. I’m just telling you because a blue key will never be as good as a green key for video. There’s just less color information to work with on the blue channel.
You are correct that Vegas doesn’t have any spill suppression or matte choker so you may need a more powerful keyer than the one built into Vegas. I would recommend the BCC Chrome Key or if you can’t afford that, the NewBlue FX Chroma keyer is good too. Both have spill suppression and matte chokers. BCC also has a light wrap which really helps sell the shot.
If you want to do it all in Vegas, I would use the Color Corrector (Secondary) before the chroma keyer to make the blue more consistent. Use it to make the lighter blue darker so that the keyer will have an easier job. You can stack multiple secondary color correctors until your blue background is consistent. Then try and key the more consistent blue color.
~jr
http://www.johnrofrano.com
http://www.vasst.com -
Thank you, John. To date, I have never yet tried to use a green screen for background. Just out of curiosity, if the foreground subject also has green elements, wouldn’t these be canceled out along with the background? I’ll just have to try it and see what happens.
I gave up on Vegas. I also have After Effects and the Keylight plug-in seems to be exactly what I was looking for. Vegas was getting closer and closer, especially using the secondary color correction, but I just couldn’t quite eliminate halos in not as well lit areas. I’ve tended to use Vegas though for almost all video needs because I find processing faster than with AE, but in the case of keying I’ll be using AE for now on.
Jon
-
You are correct, if your subject has green you can’t use a green background because they will both get keyed out. Keylight in AE is also a great keyer. I didn’t realize you had AE. Sounds like you’re all set.
~jr
http://www.johnrofrano.com
http://www.vasst.com
Reply to this Discussion! Login or Sign Up