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Greenscreen/vertical position

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Bob KarsnerGreenscreen/vertical position
by on Mar 8, 2010 at 2:56:29 am

I am doing a project in AE using green screen. I need to vertically reposition the footage of my actor
but when I do, the quality of my footage drops considerably. Artifacts appear and the edges seem to
blur. I am using DV footage. I am repositioning my footage approximately 21 pixels higher on the screen and it does not move once positioned. What am I doing wrong. The problem only shows up if I move the footage vertically.

Thanks,
Bob



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Joey ForemanRe: Greenscreen/vertical position
by on Mar 8, 2010 at 3:05:00 am

Is your y position a whole number or a does it contain decimals?
If so, try rounding off.


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Matthew KeaneRe: Greenscreen/vertical position
by on Mar 8, 2010 at 12:26:59 pm

With DV footage - and any interlaced footage - if you move the layer an odd number of pixels vertically, you will invert the field order. Assuming you're in a DV comp, if you move it an even number of pixels and, as the other poster says, make sure it's a round number, the interlacing of the footage will coincide with that of the comp and you shouldn't have any problems.


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Dave LaRondeRe: Greenscreen/vertical position
by on Mar 8, 2010 at 3:46:09 pm

You simply need to interpret the footage in the proper field order. For DV, it's lower field first. You also need to render in that field order.

And good luck trying to key DV.

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


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Bob KarsnerRe: Greenscreen/vertical position
by on Mar 8, 2010 at 4:04:03 pm

Thanks for all the input. Moving to footage an even number worked. I have been keying DV footage quite a bit the last couple of years and have gotten decent results with lots of tweaking. Lighting is the key. Thanks for the help.
Bob





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Jeremy FabianoRe: Greenscreen/vertical position
by on Mar 8, 2010 at 6:57:44 pm

Another tip with interlaced footage is to de-interlace it, export it as something like quicktime animation preset, then reimport it and key that. I've had very good results doing it that way. There's a decent workaround by Kramer for doing such things.. I'd link to it for ya but I'm at work >.>

Cheers

-Jeremy

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If you didn't supply enough information I will start making assumptions. I'm usually wrong when I assume.
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Dave LaRondeRe: Greenscreen/vertical position
by on Mar 8, 2010 at 9:48:46 pm

[Bob Karsner] "Moving to footage an even number worked."

Glad you got it to work, but you're leaving yourself open for trouble. Some time you might want to animate your footage on the screen -- without interpreting and rendering in the proper field order, you'll definitely have problems.

Personally, I'm not a big fan of deinterlacing video for use in AE. A lot of the deinterlacing techniques are pretty bad, resulting in less than good-looking video. If you need a copy for the web, you can deinterlace for the web, when the size of the picture may very well be smaller and deinterlacing less noticeable.

It's better to shoot progressive-scan in the first place.

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


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Jeremy FabianoRe: Greenscreen/vertical position
by on Mar 8, 2010 at 9:50:30 pm

True, I'd prefer progressive scan as well.. but these POS Quasar camcorders just don't seem to have that feature :( Hehe.. still trying to save up for a real camera, but these darn bills keep getting in the way.. Maybe someday, right?

-Jeremy

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If you didn't supply enough information I will start making assumptions. I'm usually wrong when I assume.
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Bob KarsnerRe: Greenscreen/vertical position
by on Mar 8, 2010 at 10:04:02 pm

Thanks guys. I would love to shoot progressive as well. I guess Jeremy and I have the same problem... those darn bills. Thanks for all the input. Right now I will just have to stick with shooting DV and tweaking until I get it to work and dream of the day I can upgrade.

Thanks,
Bob Karsner



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Dave LaRondeRe: Greenscreen/vertical position
by on Mar 8, 2010 at 10:35:12 pm

You guys must be thinking that I'm talking about some fancy-schmancy RED camera or Sony/Panasonic rig that uses cine lenses or something like that.

Got a lil' ol' Panny DVX 100 DV camera? Got an HDV camera made in the last couple of years? You've got a progressive-scan camera. Set it to shoot progressive scan: 30p, 25p, 24p or 24pa (remove pulldown from the 24p footage first). Some of these cameras may record their frames over two fields, but the images were scanned as an entire frame -- the hallmark of a progressive-scan camera.

I'll assume you know HDV video will give AE fits, and you'll take the appropriate step to remedy it.

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


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Jeremy FabianoRe: Greenscreen/vertical position
by on Mar 8, 2010 at 10:41:08 pm

HAHA NOPE!

I got me a pair of 1989 Quasar VHS Camcorders and a USB video capture card that can do 720 res :D I are poor :(

Heck I'm still using my roomie's copy of CS3 while he's off in the Airforce >.>

When I have a couple hundred $ saved up though, I'll be getting some kind of HDV came (perhaps the one you mentioned).. want something that can do 1080 and not give me a heartattack when I try to bring it into AE.

-Jeremy

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If you didn't supply enough information I will start making assumptions. I'm usually wrong when I assume.
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Dave LaRondeRe: Greenscreen/vertical position
by on Mar 8, 2010 at 11:13:53 pm

A VHS camera.... well, it's still video, I guess. And you do have a resourceful way of capturing it.

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


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Jeremy FabianoRe: Greenscreen/vertical position
by on Mar 8, 2010 at 11:50:00 pm

*grin* It's the best I can do for now. But hoping to have some money shortly, any recommendations in the $500-750 range?

-Jeremy

-------------------------------------------------
If you didn't supply enough information I will start making assumptions. I'm usually wrong when I assume.
-------------------------------------------------


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