Noisy blacks in Keylighted green screen shots

[mrbrycel]

A friend of mine hired me to do some effects for a pepsi commercial (Video Production 4th quarter final project). He gave me green screen footage of dancers, and he wanted me to key the green out, put them on a black background, and make light streaks coming from their hands. I can do all of this, but I'm having trouble getting it to look perfect. He shot on a dvx100, 24p, and I'm certain he shot at a pretty slow shutterspeed, because I'm losing half of his arm when it moves quickly. I don't think this is fixable (if it is, let me know), but it shouldn't be too distracting. My main concern is I've got a lot of noise in blacks and dark colors, mostly the male dancers jeans. I have to set the screen matte clip black to about 50 to get rid of some noise around the dancer. Is there any way to reduce the noise within the pants/dark colors?

Heres a test shot I just exported: http://vimeo.com/1721038

Any additional advice or tips on all the effects in this project would definitely be appreciated. Thanks!

[grahamdunn]

Usually if the shot is really messy and I just can't fix it all with tweaking settings, I'll break the shot up into pieces with a loose matte (one for legs and one for the upper body, for example) and key the two differently. Sometimes it's labor intensive, but you can get cleaner results by specifying your keys a little more.

[cheezweezl]

EDIT: see next post.

assuming the jeans are blue, they are probably being keyed to some extent as blue and green are not that far from each other. i just had the same problem with blue/green scrubs getting partially keyed. the result was noisy washed out colors.

the fix, key the jeans. make 2 copies of your footage layer. delete keylight on the middle one. on the top one set keylight to key out the jeans. get the screen matte as clean as possible and make sure none of the greenscreen gets keyed out. you should see jeans in solid black and everything else in white. then set keylight to show the combined matte. leave it here. go to the middle layer and set trackmatte to luma inverse. this will use the black and white matte from the keyed jeans layer above as a trackmatte. at this point you should be able to hide your bottom layer and only see jeans.

turn the bottom layer on and your noisy pants are now covered up by you middle layer which only contains clean pants.

since this is dv footage, you will probably have some trouble. dv isnt the greatest for keying. good luck!!

[cheezweezl]

OOPS. missed the footage the first time i read your post. now i see what you are talking about. i don't think my theory above will apply. however i wil leave it as it is a good way to fix a partially keyed foreground element.

hard to tell exactly whats going on from that clip but looks like a combo of typical dv issues, slow shutter motion blur issues, and maybe some settings in keylight being off.

besides the pants problem. the edges look rough overall. did you use any pre-blur? if not, try setting it at 1.5. also, try resetting the screen matte black/white levels to 0 and 100. then go tweak the screen color manually. use the eyedropper to get a basic color, then go move the color around by hand and find the point that gives you the best key. then go back and set your screen matte. this won't help much with motion blur or dv issues but will make for the best key possible.

[cheezweezl]

as far as the other effects. the light streaks look too much like jaggy straight lines. i would go smooth out the keyframes and make it look more fluid.

[Postmaster]

Key-Correct (Red Giant) has worked wonders for me on screwd up greenscreen scenes, give it a try.

Frank