Adobe After Effects Forum
Keylight question - keying out window
Keylight question - keying out window
by ClintVideo on Jan 24, 2007 at 7:19:14 pm

I've got a sample window from a manufacturer and am told to chroma-key it rotating for one of the intro shots. I've given the direction to the studio guys to light the background properly, watch out for reflections, and frame as tight as possible. I've got a pretty decent key going, but as the window rotates, I get the crawlies on the left and right vertical edges. I'm going NUTS!

Are there any little Keylight or matte choker tricks I'm missing here? Despite the fact that we're shooting on miniDV, I'd still like to pull a decent key here.

Cf




Re: Keylight question - keying out window
by TClark on Jan 24, 2007 at 8:23:18 pm

Are you using progressive footage? If not, it might help if you convert the interlaced video to progressive. Also you can use a matte choker.


Re: Keylight question - keying out window
by IanCorey on Jan 24, 2007 at 8:52:49 pm

Depending on the circumstances it might not be an intolerable amount of work to apply a simple mask along that edge and animate the Mask Position.


Re: Keylight question - keying out window
by epontius on Jan 24, 2007 at 10:36:14 pm

Ahron "super tight junk mattes" tut might help with that. It uses the autotrace feature to automate a mask around a subject....

Erik




Re: Keylight question - keying out window
by Josh J. Johnson on Jan 24, 2007 at 10:11:23 pm

Probaly a stupid question. How do you convert interlaced to progressive?

Thanks


Re: Keylight question - keying out window
by Clintvideo on Jan 25, 2007 at 5:00:06 am

I have the opportunity to have it re-shot progressive so I told the videographer to re-shoot on Friday. I'm using a matte choker but because of all the lines and angles of the frame of this window and the fact that it turns, that tends to give me wobbly shadows.

Animating masks is an interesting solution, I would need 3 masks because it's a 2-pane window, but because of the wide angle lens I get some perspective distortion that makes it look out of square. That, or maybe it's the angle between the window as it pivots and the camera. In any case, I'm really close...hopefully shooting it progressive will help tune some of that out.

Thanks for all the responses so far, I'll follow up with my results.

Clint


Re: Keylight question - keying out window
by jimmybee500 on Jan 25, 2007 at 9:34:36 am

I'd seriously consider the masks option...if it's just a static image rotating that sounds like a lot less hassle than a whole re-shoot.

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