Greenscreen -keying with DVX100

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kinski_zg

New member
hey everybody,
I'm about to do some chromakey work with dvx100...
I have previously done it, but it was somewhat easier to key since the final result was stylized/graphic. pretty much I need the subject to stay the way it is, realistic, and fitted with relatively realistic backgrounds..
now, i'm worried about the smoothness of edges...this seems to be the problem, as i have read some articles in american cinematographer concerning this issue...

what are your experiences and advices on this? Is it possible to solve this problem in easier way with a particular software (so far we used after fx)
what do you generally think about this..

thnx a lot guys !

.v
 
Make sure your key color is nowhere in your subject. Make sure it's lit well and that you get little spill. Make sure your subject is let well.

In post, before you key, add a little chroma blur.

Serious Magic Ultra 2 is a very good DV keyer. Better than you'll find in multi-purpose software.
 
I agree sperate one light for the background and another light for the talent. Serious magics ultra 2 kicks but for this. Donot use one light to light it all this will not work. Also tell yor talent to not have there back hit the green screen to atleast step 3-5 feet away from it. This will grant u enofe space to light the talent sepretly from the green screen also prevents shadows. If u do all these steps well you should not have a problem keying.
 
You can't avoid the lack of smoothness of the edges, those are good old artifacts from DVX's compression algorithm.

Serious Magic Ultra 2 is good, however if you want the real deal program that allows you a lot more control over removing artifacts, and much more powerful way to deal with the green screen then I recommend this program

http://www.redgiantsoftware.com/primattekeyer1.html

it has kicked anything elses arse including Serious Magic Ultra. The results even with compressed footage were awesome.

The other tips are
1) make sure the background is equally lit, setup 2 light sources on each side at 45 degree angle, about 3 to 4 feet away from the background. THe two overlapping light sources should result in equally lit background. Use a light meter or another tool to make sure it's equally lit.

2) Make sure the background is nice and smooth, I find it that less stretching you do on the background, better the results.

3) Tell your subjects not to wear light colors, like white, that just soaks the green in

4) DO NOT over light the background, if you use too much "fire power" you end up with very bright background that will end up casting a green haze all over your subject

5) If there's movement involved with your subject, make sure you it's subtle, you will have hell of a time dealing with motion blur.

6) Get as much of the subject in your shot. Try and to leave small amount of margins around the subject. The more data you get results in smaller artifacts around the edges. Keep in mind, the size of those artifacts is always the same, so the bigger the subject is on the scene, the smaller the artifacts are comparing to the subject. Just make sure you compensate for potential subject movement. Even if you ask the subject to stay as still as possible, it is in our nature to shift. Only exception are trained actors who know the name of the game. Otherwise, watch out!

7) Get a friend and start testing, record the distance of light sources, subject and background distance. Get that test footage into whatever program you decide to use and start looking at the results. Keep in mind, working with these keying programs could be tricky. Get good with one and then make sure you use same procedure for all your tests. Otherwise you might stumble upon great result due to you using the program properly rather then proper scene setting.

8) If you're planning on doing a lot of this, get andromeda chip put into your DVX. It will yield uncompressed HD footage which makes keying the footage possible for 2 year olds.


Good luck
 
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Try the "Keylight" keyer in After Effects 6.5 or 7
It has more tools than the regular keyer
The spill suppression feature is excellent as it will tint any green in your highlights to a user definable specular color. It helps with less than ideally lit greenscreens and also for things like leather jackets and sunglasses and bald heads that tend to pick up green in their highlights.
 
Well, it's not just the "DVX's compression algorithim" in the sense that it's DVX-specific. Primarily, it's the 4:1:1 (or 4:2:0 PAL) color space of DV and the low 720x480 resolution of SD.
 
I didn't want to make it sound like it's specific to DVX. SD or HD, both end up being compressed due to the sampling, the HD get an extra boost of having to store all that data on DV tape, perhaps SD only gets partial treatment.

Either way, it makes the footage less desireable for this sort of work right?
 
Depends on the flavor of HD. The HVX, with DVCPRO-HD, has twice the color sampling of DV or HDV. The same holds true of DVCPRO-50 in SD. You get cleaner keys.
 
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