Green Screen Correction using Sony Vegas 10 Movie Studio

[Dan Lindley]

My wording may be wrong but look for the “shrink image” feature of the green screen plugin. That just might be the answer. But…I can’t recall if that’s a Sony plug in or one I use from NewBlue. With it you can slightly reduce edges around the green screened subject. I find it works well. Good Luck.

[John Rofrano]

The Sony Chroma Key is *extremely* primitive and doesn’t have any way to shrink the matte or do spill suppression (which is your problem). You should really look into the NewBlue Chroma Key tool. It’s part of their Video Essentials II package. It doesn’t cost a lot and should give you a much better result than the built-in Sony plug-in.

~jr

http://www.johnrofrano.com
http://www.vasst.com

[Patrick Mckenna]

Hi guys and thanks for the replies,

I downloaded the free trial of New Blue’s Video Essentials II and tried the chromakey effect and unfortunately it doesn’t make it any better. I stayed away from the Sony chromakey tool because of one of the actors were a green t-shirt. Instead I used the secondary color correction tool. I got the result that I want except for the green screen “spill”.

When trying the New Blue chromakey, it does give a lot more control than the Sony chromakey version but it csuses the footage to look very very grainy and seems to “wash out” the colors in the shot.

[John Rofrano]

[Patrick McKenna] “When trying the New Blue chromakey, it does give a lot more control than the Sony chromakey version but it csuses the footage to look very very grainy and seems to “wash out” the colors in the shot.”

Make sure that you check the mask and make sure it is pure black and white. If it has any gray, it will wash out your video. You need to avoid this by fine tuning the mask.

~jr

http://www.johnrofrano.com
http://www.vasst.com

[Patrick Mckenna]

Thanks again for the replies.

I tried the masking solution and regardless of how hard I try, I can’t seem to get rid of the greyness. This is a result of the problem of one of the actors wearing the green t-shirt. It’s his tshirt that is where the extreme grain is. When using the mask. If I increase the values to make his t-shirt entirely white, it causes the green screen to become more grey than black or similarly if I make the green screen pure black, the t-shirt becomes grey.

Using the secondary Color corrector instead of the chromakey tool achieved the best results overall except for the green spilling onto the edges of the actors, particularly their faces. Is there any other tool out there that I can use to touch up the spilling problem?

[John Rofrano]

What if you use the Secondary Color Corrector to change the color of the green shirt? Then feed that into the Chroma Key.

~jr

http://www.johnrofrano.com
http://www.vasst.com

[Patrick Mckenna]

Thanks for the swift replies John.
I’m new to the whole Vegas experience so I wouldn’t be too familiar with how to do that. I generally get my ideas from advice that I google.
If I was to change the t-shirt colour in the secondary color corrector, would I not mess up the color for the whole scene? What I mean is, I shot an outdoor scene that this car scene leads up to and having the actor have a different color t-shirt in two different shots would totally mess up the continuity. Or do you mean something different?

To explain it from the start, I tried the Sony plug-in which as you said it very primitive, and that caused the actors t-shirt to go dark blue. So I googled color correction when using green screen and I was advised to use the secondary color corrector by adjusting saturation, hue, etc and bringing the alpha channel right down to make the green screen transparent and voila, everything is perfect except for the fine green edging or “spill”.

I then tried your advice of using New Blue’s chromakey which is much better than the Sony one except it left me with the grain problem and washed out look.

If you want I can try and post up a picture of this particular shot later this evening without any of the added tools (chromakey, color corrector, etc) where it is the actual footage with no effects added and it might give you a better idea as where I should begin.

[Patrick Mckenna]

Hi John.

Below is a snapshot of the basic footage shot without any effects or tools used. This might give you a better insight into my problem.

3286_greenscreenproblem2.jpg.zip

[John Rofrano]

[Patrick McKenna] “If I was to change the t-shirt colour in the secondary color corrector, would I not mess up the color for the whole scene? What I mean is, I shot an outdoor scene that this car scene leads up to and having the actor have a different color t-shirt in two different shots would totally mess up the continuity. Or do you mean something different?”

You didn’t mention that there were other scenes besides the chroma key shot. Yes, this will not work if the green shirt needs to be in other scenes. You could correct it back again. For example, make it bright red, feed to chroma key, then add another secondary color corrector to make the bright red shirt green again.

~jr

http://www.johnrofrano.com
http://www.vasst.com

[Patrick Mckenna]

Hi John,
Thanks for the replies. Sorry I never mentioned about the green t-shirt being used in subsequent scenes. I tried secondary colour correcting the green t-shirt to red and it is heartbreaking work. I’m nearly at that stage where of giving up and I’ll just have to except that the green screen footage is not going to look the way I want it. I think that the green screen was too close to the actors and car and that it caused the spill of green light into the car. And then there’s the huge error of the actor wearing the green t-shirt…..

I just thought that there would be something very simple that could trim away the green edging spills and even if I could color corrected the green spill/edging so it might blend better with the background.