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Bad results with Keylight - Compressed file

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Danny Winn
Bad results with Keylight - Compressed file
on Oct 6, 2010 at 11:36:40 pm

So I pride myself in being able to key out Greenscreen footage very well but I've run into a problem with a 5MB .mov file. The full widescreen SD greenscreened footage was shot perfectly but the clip is nearly 2 minutes long and the file is only 5mb's which tells me that the file settings are very low and the compression very high.

I used my normal Keylight procedures for screening but even though the green is gone with clean edges the remaining footage has horrible moving artifacs within it.

Is this because of the file compression and other settings? Can I get a better result?

If anyone knows please advise. Thanks much!


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Steve Blacker
Re: Bad results with Keylight - Compressed file
on Oct 7, 2010 at 1:51:24 am

2 minutes at 5mb? That pretty much says it all. As you've already said, it's garbage.

It's only work if you'd rather be doing something else...


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Kevin Camp
Re: Bad results with Keylight - Compressed file
on Oct 7, 2010 at 2:40:13 pm

you could try the reduce dv blockiness preset... it does what's commonly called a chroma blur.

it adds the channel combiner effect, converting rgb to yuv, then uses channel blur to soften the gb channels (now uv channels) then uses channel combiner again to change it from yuv back to rgb.

don't expect wonders from this, the artifact reduction is slight.

also, if your key is good, render the footage before trying to reduce the artifacts.

also, frame blending (and frame blending effects like cc widetime and cc time blend) can sometimes help lessen artifacts and noise, but they may create unwanted 'blurring' if the subject is moving much.

Kevin Camp
Senior Designer
KCPQ, KMYQ & KRCW


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mathew fuller
Re: Bad results with Keylight - Compressed file
on Oct 7, 2010 at 10:24:06 pm

If you have the plugin "Key Correct" the "smooth screen" plug might help.

The higher they fly... the much.
http://www.morecompletefx.com/reel.html


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Dave LaRonde
Re: Bad results with Keylight - Compressed file
on Oct 7, 2010 at 10:33:19 pm

...but in the end, the bit rate on that file is something in the neighborhood of 0.2 MB/Sec. The DVCPro HD footage I regularly key weighs in at 100 MB/Sec.

Even if this is postage-stamp-sized video, I hope you don't expect miracles.

Dave LaRonde
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA


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Jon Bagge
Re: Bad results with Keylight - Compressed file
on Oct 7, 2010 at 11:34:02 pm

Compositing is like a sewer. What you get out of it depends on what you put into it!

(my apologies to Tom Lehrer)

--------------
Jon Bagge
Editor - London, UK
Avid - FCP - After Effects


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Danny Winn
Re: Bad results with Keylight - Compressed file
on Oct 8, 2010 at 4:04:44 am

Thank you everybody for the response, I was able to get a decent key (although no perfect) with some of your suggestions. In the end though crappy footage creates more crappy footage.

I didn't shoot it, I just got stuck with it;)

Thanks all!


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