View Full Version : Green Screening


Matt Erdos
September 25th, 2003, 03:54 PM
I was hoping someone could help me out with a couple questions that I have. I am fairly new to green screening and I haven’t turned out anything good yet. Usually my subject is too faint, not good color, jagged edge and stuff like that. I light the background evenly and I have some overhead lighting for the subject but it doesn’t seem to turn out too good. I use halogen court lights for the background and I try to keep the intensity off so it doesn’t get too bright. I have not tried it yet, but I just bought the new sony vx2000 hoping that I would help with clarity. I use adobe after effects for the keying. If there is anything that you could suggest that would be great. Also, I am not sure about the setting of white balance on the camera, does anyone know what it should be set at? If anyone can give me any type of feedback that would be great. Like I said I am pretty new to this and I would like to be able to turn out a clear good subject after keying the color. Thanks.

Mike Rehmus
September 25th, 2003, 05:44 PM
I don't much like the keyer in After Effects. I much prefer the Canopus products for that. This is because the Canopus converters the image to 4:2:2 so their keyer works better right out of the box.

Otherwise, AE has enough tools to do it OK. But they are somewhat tedious from what I can see.

Is your subject far enough away from the screen so that you are not getting green spill on the edges? If you are and cannot move the subject further away, you may need to light the subject edges with a little bit of orange light.

The VX-2000 probably won't make much difference unless your present camera is really bad.

White balance for the light falling on your subject.

Matt Erdos
September 26th, 2003, 08:08 AM
I just have one more question. I am having a problem with the video once I bring it in, it is clear but the hands when they move fast look like the pixels don't match up and become jaggy. What would be the reason for this? Shutter speed and if so what should it be set at to clear that up.

Thanks Matt

Mike Rehmus
September 26th, 2003, 10:10 AM
You probably have the wrong field order set in After Effects.

When you add a project to the Render Queue, you go into Render Settings and change Field Render to the correct setting for your avi files. The order is normally determined by your editing software.

In After Effects, the choices are Upper Field First or Lower Field First. Other programs may call these fields Odd and Even or First and Second. I'm certain there are other terms as well.

Kristof Indeherberge
September 28th, 2003, 03:53 AM
Thing is, to pull a nice key you should both have a hard and a soft key and mix the two. Using a matte control for the blending, you can tweak how large the softer outer edge is (depends on your subject and motion blur amongst other things)

Maybe use a grain killer in your flow too?

Another golden tip is to upsample your dv footage from 4:1:1 to 4:4:4 - the proper way. That way you have much cleaner edges. In short, you should use something like Digital Fusion for that. It's addictive and that's what we use at work.

And blur your new backgroud with your key's matte prior to merging both. Oh, Pull an edge mask and work from that so you can fake radiosity on your final comp...

Matt Erdos
September 28th, 2003, 08:22 AM
Thanks I will try all of that. I appreciate everyones help, it worked out alittle better this last time. The only problem I am having is with the green around the feet. It is like a lil green shadow. But thank you everyone for all your help if you have any suggestions on the green around the feet that would be cool.

Juan P. Pertierra
September 29th, 2003, 06:40 AM
I was under the impression that if you specified 16-bit color in the project settings in After Effects this would be equivalent to working in 4:2:2, is this correct?

Mark Jefferson
September 29th, 2003, 06:53 AM
Here is a copy of something I post on greenscreening in Premiere a little while ago. Hope this helps:

-------------------------------------------
I've done quite a bit of green-screening lately, and this procedure will work with any video editing app that has layers (I use Adobe Premiere 6.5, but I don't see why this technique wouldn't work with any editing app). This info applies specifically for Adobe Premiere 6.5, however.

Lets face it: Premiere's chroma-keying is terrible, but I've found a way to get very professional looking composits using only Premiere with no additional plugins or other software:

1. Shoot your green-screen footage. It's good to have a well lit green-screen, but even lighting is more important then brightness (You'll see why in a minute).

2. Capture your footage. Once you bring it into your editing app, load your footage on the first overlay track (layer 2 for Premiere)

3. Apply the filters to adjust the saturation levels of this video clip to 200% or better, especially for the green. This will really bring out the green background. Sorry, can't remeber the exact name of the filter, I'm not in front of Premiere right now, I'm doing this from memory...

4. In the transparency settings, choose Chroma-Key from the drop down and use the eye-dropper to sample the green background, then choose "Mask Only" on the right side of the dialog. Close the Transparency window.

5. Sometimes, you will have to clean up parts of this mask, so if you need to do this, simply create a title and apply white or black shapes to the imperfections to get rid of any trouble spots. You may have to keyframe some of these things so you might have to create multiple titles, it just dends on how "clean" your green screen footage is.

5a. At this point, you can either create a virtual clip or render out this video into another clip. I usually just render this out because my wife says I can't feed both my video jones AND my computer jones (I have a slow PC). We'll be using this clip to create a "cookie-cutter" for our composited final video

6. Make a new project, load your clips, including the mask you just created, and put your plate footage (thats the background footage on which you will lay everything) on the first track (1a for Premiere)

7. Put the mask you just created on track 2 and change the transparency settings for this clip to "track matte".

8. Place your original greenscreen clip On track 3. Change the Hue so the clip is relatively close to the same color as your plate footage. This goes a long way towards eliminating a white or black line around your composited image. You can also play around with the opacity settings. Change the transparency to track matte.

9. Put your original greenscreen clip on track 4, and change the opacity of this clip to around 70%. You may have to adjust the saturation to add a little color back into to image. Again, change the transparency to track matte.

10. Render your image (go get a beer and come back later).
--------------------------------------------------
Sounds like a lot of work, but the results are worth it. No more fuzzy edges. No more green or blue tinted composits. Crisp, clear images. Who needs Ultimatte!

Sorry for such a long post, but this is the exact procedure I use, and I get better results this way then when I use AE.

Cheers,
slakrboy

Matt Erdos
October 6th, 2003, 08:49 AM
Thanks everyone again for your inputs. I finally got a good key, but the only problem is. After effects says I don't have enough memory to export. I have been trying to figure it out for a couple days and it is driving me out of my mind. There is no way it can be out of memory. The clip I am exporting is a 21 second clip, with two seperate clips and a background. My computer is pretty robust so that is why I don't think it can be out of memory. I have a dual 3.06 ghz xeon processors and 1 gb of ram. I have over 200 gb on my system probably about 150 gb free. No clue why this would be saying that. Is there a way to allocate more memory with windows to After Effects? Any help will be appreciated. Thanks

Mike Rehmus
October 6th, 2003, 10:11 AM
I've never had that problem but I think you may be out of scratch drive space? Where is your's set? You set that up under Preferences.

Robert Poulton
October 6th, 2003, 11:15 AM
Hi Matt,

You should goto www.dvgarage.com and look at their dvmatte plug-in for After Effects. It works amazing for minidv footage and the keying process is easier. I have used it on crappy greenscreen and it pulled a great matte.


Rob

Matt Erdos
October 6th, 2003, 12:52 PM
I looked under the preferences settings in after effects and I saw cache so I went to that and changed image cache to 999% and same with maxium memory usage 999% that gives me 2027mb. I tried to export the quicktime then and it said that

After Effects: Not enough memory to create
2097152kb requested and 2014020kb available.


Quicktime Proccess failed.

It seems like can export the quicktime without audio but once I check the box for the audio to output too it gives me that error.

No idea where to go with this. Any ideas?

Thanks,
Matt

Jim Quinlan
October 6th, 2003, 01:46 PM
Another alternative would be to look at UltraKey by seriousmagic (http://www.seriousmagic.com)

It makes keying extremely easy and comes with a lot of virtual sets. Plus you won't find a better support staff anywhere.

Mike Rehmus
October 6th, 2003, 11:19 PM
I think you need to talk to the AE experts on COW or on the Adobe-sponsored forums

David Woodland
February 9th, 2004, 12:21 PM
Where can I purchase a green screen. I hardly know anything about green/blue/red screens but I would like to learn them so I can apply them to a new rollerblading film I'm working on. Also, how expensive are they?

Rob Lohman
February 10th, 2004, 03:04 AM
That's like asking where you can buy a car and how expensive
that is (without stating anything else).

There are a ton of different blue/green/orange and whatnot
screens out there. You can even get official paint for the color
or try to get some similar color from a local paint shop.

One of our site sponsors (which has the main site down at the
moment, so I'm linking to their Yahoo store) has a small portable
version as well: http://store.yahoo.com/bhphotovideoproaud/labgc67g-reg.html

Dustin Waits
February 10th, 2004, 09:02 AM
<<<-- Originally posted by David Woodland : Where can I purchase a green screen. I hardly know anything about green/blue/red screens but I would like to learn them so I can apply them to a new rollerblading film I'm working on. Also, how expensive are they? -->>>

I got mine from Ross. Bright green bed sheets were on sale. = ]

Josh Brusin
February 10th, 2004, 04:38 PM
after effects benefits from the ultimatte keyer plug-in... the color key function doesn't serve very well... I bought Discreet*s combustion and was blown away by the keyer. Out of the box it rocks. I'd suggest looking at Combustion 3... if you're on a G5 it's 64bit to boot!
(Still like the timeline in AE tho!)

Rob Lohman
February 12th, 2004, 03:43 AM
Isn't that quite a pricey package (combustion)? Some people have
reported good success with builtin keyers in NLE's if you first
color correct the greenscreen to flatten the color range.

Robert Knecht Schmidt
February 12th, 2004, 04:23 AM
Rob, occassionally discreet offers deals that halve the price in addition to bundling plugins and complementary applications, making combustion attractive to the same sorts of DV enthusiasts that would buy, for example, Premiere Pro or After Effects.

Rob Lohman
February 12th, 2004, 05:38 AM
Interesting to know Robert, thanks! Combustion is a very nice
application. But quite complex, keep that in mind (not a one
button application so to speak).

Robert Knecht Schmidt
February 12th, 2004, 08:55 PM
I find it easier to learn, use, and manage than After Effects.

Nick Jushchyshyn
February 12th, 2004, 10:30 PM
If you want to just start experimenting with bluescreen/greenscreen work, here's a tutorial for building a large, inexpensive screen yourself (http://www.jushhome.com/Bluescreen/Bluescreen.html).
A portable version is also shown.

I'm planning on getting Combustion later this year myself, but for now, Media Studio Pro has been doing a fair job of processing the composites.

Have fun.

Hans Henrik Bang
February 14th, 2004, 05:21 AM
The people behind the inexpensive special effects software AlamDV have also recently released "The Chromanator".

I haven't tried it myself, but just thought I would add a link. You can probably find someone here with experience with it.

http://fxhome.com/

Robert Knecht Schmidt
February 14th, 2004, 05:47 AM
Thanks for sharing your tutorial, Nick.

As much success as you've had with Ulead, I think you will love the step up from MSP to combustion.

Nick Jushchyshyn
February 15th, 2004, 08:17 PM
Thanks for the feedback Robert.
Yeah, I'm looking forward to it. Just need some time for my bank account to recover from a GL2 purchase back in Dec. :)

I have looked into Chromanator.
Looks like it would be good if you have only an editor like Premiere or Vegas (just basic compositing features) and don't want to invest much in compositing.
I tried the demo, though and found that it's pretty limited in functionality right now. My existing editor was able to pull keys with the same quality or better so I decided to just keep saving up for Combustion.

Have fun.

Josh Brusin
February 22nd, 2004, 05:29 PM
I got Combustion last August for about $800... came with a free upgrade to version 3.... great service albeit a weird authorizing process.... autodesk is the parent company.
For straight keying it buries FCP... Ultimatte is pretty good but since C* is sooo good I have no reason to mess with AE for keying (same thing goes for color correcting. C* rocks... would like to buy magic bullet but see no reason right now- look forward to exploring it as I'm a software junkie).
C* is more compatible with AE prod which is more expensive in the first place $1400ish not to mention ultimatte, magic bullet, other plug-ins... on the upside most plug-ins work in C*...

Mike Rehmus
February 22nd, 2004, 06:25 PM
What keeps me from doing any more business with Autodesk is what happened with my copy of AutoCAD. I'd been an Autodesk customer since they started the company. In fact, I jointly developed a product with them way back when.

Around AC 10, they decided that their customers HAD to upgrade whenever Autodesk told them to or they no longer qualified for upgrade pricing. Upgrade prices would then equal the price of a new copy of AutoCAD. Arrogance the likes of which I'd not seen since Ashton-Tate if you remember them.

Needless to say, I purchased my CAD software from a different company. May your experience with them be different.

Adobe, OTOH, willingly upgraded my Academic version of AE to a commercial license for just the price of an upgrade.

Josh Brusin
February 23rd, 2004, 04:32 PM
that sucks...
I just got off the phone with avid about upgrading a DV Xpress station that missed the "deadline" to upgrade... parallel dongle 1.5 NT version. I am a FCP user but figured I'd call them to see if they'd give me an upgrade as it was unregistered. No dice. As far as I can tell every software package - from Flash to Photoshop have upgrade rules. Did autocad restrict your use of your existing package? That would be odd an unacceptable.

Mike Rehmus
February 23rd, 2004, 05:03 PM
No but of course they provide no support whatsoever for that version so it is just a bit obsolete.

I don't/won't deal with Avid or Meda 100 for that same reason. When it came time to upgrade the schools Media 100 system, it was cheaper to buy a New G4 with FCP than to upgrade that lose system of unreliable programs that they called a Media 100. It wasn't cheap to start with, cost a fair amount for required annual maintenance (the only way one could get upgrades) and the reliability and performance was dismal. Nice video though.

Josh Brusin
February 24th, 2004, 10:44 AM
cads tough but as far as old software support goes boards like this are wonderful...
thanks.