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jmoore5036
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Green Screen with Keylight problems

Apr 23, 2012 10:03 AM

I am trying to remove the green screen background.  I am able to remove it but there looks like wiggling lines around the outside of the person after the green screen is removed.  What causes this and how do I fix it.  I shot the footage on HDV cassette.  Could this be an issue with quality of the footage.  I have tried messing around with the effects and settings in keylight but to no avail.  Any help would be appreciated.

 
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  • Currently Being Moderated
    Apr 23, 2012 11:07 AM   in reply to jmoore5036

    jmoore5036 wrote:

    I shot the footage on HDV cassette.  Could this be an issue with quality of the footage.

     

    It sure could be.  HDV pretty much stinks on ice for keying.  It has lousy color resolution, and it's recorded that way: you can't make it look better.

     

    But proper lighting also makes a HUGE difference in chroma keying success.  Since we don't know if you followed normal good lighting practices, we can't rule that factor out either.

     

    Nor can we rule out that you tried to use Keylight intuitively, which is a big no-no... not to mention counter-productive.

     
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    Apr 23, 2012 11:35 AM   in reply to jmoore5036

    +1 to everything Dave said. Keying is an art, not something you do en passant. It requires proper preparation just as it may require additional steps. HDV is certainly not ideal, but not impossible, eitehr. Without some screenshot or something, nobody wil be able to give specific advise, though.

     

    Mylenium

     
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    Apr 23, 2012 1:32 PM   in reply to jmoore5036

    Ahhhh, there is a BUNCH of useful information out there!  I googled "lighting for green screen" just to see and came up big time with good stuff.

     

    There are keylight training resources to be found in AE's Online Help:

    http://help.adobe.com/en_US/aftereffects/cs/using/WS3878526689cb916558 66c1103906c6dea-7bfda.html

    Just look at the second section heading.

     

    You'll also fine useful stuff on the Creative COW:

    http://library.creativecow.net/search.php?q=keylight+&order=t&view=&ca t=14&f%5B%5D=2

     

     

    And I have to be frank: from the looks of that window grab, you need help lighting for green screen.  Hot spots on the green screen make life very difficult.  More light needs to fall on the subject than on the background.  The subject needs to be placed away from the background: a good six feet for starters, to reduce a nasty phenomenon called light spill, which is when the color of the background reflects on the subject.

     

    And don't forget: if you can't get useful lighting instruments, Mr. Sun can be your friend: angle the screen so it's in shadow, add fill light & back light to the subject with reflectors, and you're well on your way to good lighting.

     
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    Apr 23, 2012 10:45 PM   in reply to jmoore5036

    Hi,

     

    The Creative Cow site that Dave has suggested is really worth the time. the 4-part green screen tutorials are easy to understand, yet highly detailed. It also points you to a very good site that can be used to practice your keying on.

     

    You are lucky to be doing this as a hobby! :-)    I have joined a company and the green screen effect is 90% of what we need to do, and I am the After Effects guy - well, i hope to be after a few more months of training, reading and tutorials!

     

    enjoy

     

    Pierre

     
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  • Currently Being Moderated
    Apr 24, 2012 8:22 AM   in reply to jmoore5036

    Personally, I wouldn't go looking for a new camera quite yet. 

     

    You still need to become adept at lighting & shooting for chroma key, which will improve your results significantly.  You still need to understand that pulling a good key is rarely a "one click and I'm done" deal: sometimes it can be a very complex process, with multiple layers, animated masks and rotoscoping. Shooting a subject from head to toe, a subject with wispy hair and see-through objects are particularly aggravating.

     

    I'd say you should learn how to pull an acceptable key with what you have first, and save those nickels & dimes.  You might discover you get results that work for you. 

     

    If you just can't wait, look at a Panasonic camera that shoots to P2 cards and records in DVPro HD or AVC Intra, not AVCHD.  They're probably the most affordable cameras out there with good color resolution for chroma keying.   Please don't let all the blood drain from your face when you look at the price tag.

     

    So what about the price tags on the BEST cameras for shooting chroma keys?  Depending you your needs, they can vary in price from an entry-level Mercedes to a totally tricked-out Corvette.  Lenses, filters, viewfinders, matte boxes, and audio & video recording devices are extra.

     
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    Apr 24, 2012 3:33 PM   in reply to Dave LaRonde

    I reiterate Dave's recommendation.

     

    Read and view the resources here, especially the ones about shooting and acquiring footage for keying:

    "keying introduction and resources"

     
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    Apr 25, 2012 12:34 PM   in reply to Dave LaRonde

    Dave LaRonde wrote:

    If you just can't wait, look at a Panasonic camera that shoots to P2 cards and records in DVPro HD or AVC Intra, not AVCHD.  They're probably the most affordable cameras out there with good color resolution for chroma keying.   Please don't let all the blood drain from your face when you look at the price tag.

     

     

    Well, THAT'S wrong: I meant to write DVCPro HD, and not DVPro HD. 

     

    A search for that fictional DVPro HD would either lead no place, or worse still, someplace bad.

     
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