Chroma Keyer Grief!

transco wrote on 7/6/2003, 10:30 PM

I'm having trouble with the Chroma Keyer as follows... I have a pure Green Screen (0,255,0) and use the Pure Green Screen Chroma Keyer. The pure green area turns transparent (good), but any green, regardless of color is also made transparent. For example, surgical scrubs which are Sea Green (51,204,153) end up being sort of a purple color. I've played with the thresholds, but that doesn't help. I've used Premiere for years and never had this problem. When I select "Green Screen" only the pure green is made tranparent. I can't understand why Vegas doesn't work.

Comments

Luxo wrote on 7/6/2003, 10:55 PM

Can you post a clip or frame of your raw video?

PeterWright wrote on 7/6/2003, 10:59 PM

Have you used the colour picker to select the actual colour of the screen?

This, combined with setting the lower and higher thresholds normally does a good job.

If greens in the foreground are close to your screen colour, you will of course have problems - a blue or other colour screen may be better if there's lots of similar greens.

MUTTLEY wrote on 7/7/2003, 3:30 AM

Seems to me a bad choice in letting the talent wear green anything. Ya don't wear blue in front of a blue screen for obvious reasons. Mayhaps I'm just uneducated and you should be able to use any other green but " pure green " as you say, but I would never have assumed that. If what you say is true that you've never had prob's like this in Premier, please take it in there and post some before and afters, I'd love to see it.

- Ray

ray@undergroundplanet.com
www.undergroundplanet.com

RexA wrote on 7/7/2003, 4:31 AM

I haven't actually used this, but if you check 'show mask only' on the FX, you should be able to see in advance how it is going to work. I'd think if you adjust the color and thresholds there you will probably find a setting that will work for your colors (unless they are really too close to separate).

starixiom wrote on 7/7/2003, 6:06 AM

I find it funny how people always say "Premiere does it this way....there must be something wrong with Vegas"

I dont know if this will help, since i havent seen your clip in question, but it seemed to work for a fellow Vegas user. Here was the advice given to them:

"First, duplicate the text track so you have two identical tracks. Then on one of the tracks you need to use the chroma keyer and contrast to get the text all one color (ie: white) and the background just leave black. Now put the black/white video just above the original text video and click the mask button on the very left side of the lower track. Now you have a mask that exactly follows the text, and will allow only the text itself to show, while all the black is set to transparent. If you find that it actually does the opposite of this, go into the mask generator and click the 'invert' box.
Now, if you just put the picture or video you want to appear in the background in the third track down, it should accomplish your goal."

I know this response deals with Text and Black and white, but i think the principle is still the same. Hope that helped.