Can V5 Chroma Keyer pull a good key or do I need?

Randy Brown wrote on 7/1/2008, 9:52 AM
Yes I know I need to upgrade but just wondering if the V5 Chroma-Keyer is sub-standard.
Here's what I've done after reading this tut on greenscreening but I'm still getting unusable results:
-Covered all windows from bleeding in light.
-Placed 2 softboxes evenly on my wrinkle-free, tightly-stretched green screen (checked for even lighting by opening iris and seeing zebras evenly distributed)
-placed a spot on the subject (dolls) with barndoors preventing spill onto screen
-after placing footage on timeline I applied the chromakeyer (again V5), deselected the check mark, took large screen sample with the eyedropper, selected the checkbox again (to turn on chromakeyer) selected show mask only, then slid high threshold to left until all white subject and low threshold to right until background all black.....or at least tried to do that.
When I slide the high threshold to the left the subject does start getting all white but not before the background starts turning white also. I try to split the difference between the low and high but still crap.
Here's another thing that's maybe worth mentioning: when I use the eyedropper on the greenscreen it looks much darker than what's showing on my external TV monitor. I know the LCD will look darker than a TV but when I select the green screen preset in chromakeyer I get a cleaner key.
I realize there are many factors involved in doing this process but maybe someone has a suggestion??
TIA,
Randy

Comments

TheHappyFriar wrote on 7/1/2008, 10:29 AM
the Vegas chroma key isn't perfect. For what it can't do I use cinegob's keyer ([url=http://www.cinegobs.com/]). Pretty much does anything vegas can't, they overlap quite a bit. Only bad part is it's not a plugin. But that's the only bad part. :D
Randy Brown wrote on 7/1/2008, 11:16 AM
Well the price is certainly right...I was afraid I'd have to buy Serious Magic (or whatever it's called now) or something.
I'll check it out Happy...thanks very much!!!
Randy
logiquem wrote on 7/1/2008, 11:27 AM
Hi Randy,

Did you try first to apply a chroma blur FX before the chromakey FX? Pretty efficient for me and i got very good keys this way (note that i use a very well lit background). Hope this help.

Bastien
rdolishny wrote on 7/1/2008, 11:30 AM
I get outstanding keys with chroma blur + chroma key. You should upgrade anyway. It's been a while. :)
logiquem wrote on 7/1/2008, 11:36 AM
BTW, a couple of other tricks:

1: crop anything you don't need on the left, top and right sides
2: sample the color from the most difficult region to key (around subject's hairs for example)
TheHappyFriar wrote on 7/1/2008, 11:37 AM
just an FYI, there's no difference in the V5 chroma key & the V8P. So if that's all you want and you do a lot, a 3rd party program/plugin may be the best bet.

Randy Brown wrote on 7/1/2008, 11:52 AM
Okay, Chroma Blur...I should have mentioned in the initial post that I did try ChromaBlur (as per the tut ) but it appeared to do nothing at all ( even when using the maximum blur preset) except slow everything to a crawl ...ie I slide the thresholds in ChromaKey and it takes 5 seconds to react. Granted it's time to upgrade but it is a P4 3ghz and 4 GB RAM and I am still SD.


...and i got very good keys this way (note that i use a very well lit background)...
I have tried with 2 softboxes at highest setting (400 each I think)

You should upgrade anyway. It's been a while. :)
I know you's right : )

Randy
Randy Brown wrote on 7/1/2008, 11:56 AM
crop anything you don't need on the left, top and right sides
haven't heard that one...you mean in post, not just make the shot as tight as possible right?

just an FYI, there's no difference in the V5 chroma key & the V8P. So if that's all you want and you do a lot, a 3rd party program/plugin may be the best bet.
Still being SD I think you're right.

Thanks everyone,
Randy
Randy Brown wrote on 7/1/2008, 12:23 PM
The Happy Friar said: For what it can't do I use cinegob's keyer (www.cinegobs.com/). Pretty much does anything vegas can't, they overlap quite a bit.
I installed and tried to load the avi but got an error stating : The video file could not be opened. You are probably missing a code
Doesn't say what codec and the online help search turns up nothing.
Any thoughts as to what codec I could be missing?
TIA,
Randy
SCS PBC wrote on 7/1/2008, 12:31 PM
There is an excellent tutorial in the August 2007 SCS newsletter that gives some great advice on using Chroma Key along with the Secondary Color Corrector, all within Vegas.
daryl wrote on 7/1/2008, 1:00 PM
Randy, I had the same problem. I ended up downloading avisynth and installing it, then I pulled video in through the "import using avisynth" option, worked great.
Laurence wrote on 7/1/2008, 1:40 PM
I see that AviSynth only seems to be compatible with 32bit Windows versions.
kkolbo wrote on 7/1/2008, 1:58 PM
Randy,

It sounds like you have improperly lit the situation for a basic chroma keyer like Vegas has in it. You mention only using one spot light on the doll. That means that the fill on the doll is probably coming from the bounce off the green screen. That will cause what you are talking about. You really need to add a fill light and a back light to overcome bounce from the screen. Make sure that the doll is as far from the screen as possible. Six to ten feet is usually good if you are lighting the screen with under 1000 watts total.

The photos in the tutorial were not doctored in any way. As you can see, an acceptable key is possible in Vegas, but it must be lit properly to work.

Keith Kolbo
Randy Brown wrote on 7/1/2008, 2:16 PM
I see that AviSynth only seems to be compatible with 32bit Windows versions.
then I guess the Avisynth suggestion wouldn't help me...thanks anyway Daryl

You really need to add a fill light and a back light to overcome bounce from the screen. Make sure that the doll is as far from the screen as possible. Six to ten feet is usually good if you are lighting the screen with under 1000 watts total.
Actually I added a fill (instead of just a bounce) after I first posted and it did seem to help some. I'll try a back light also. BTW, the doll is about 11 feet from the screen. What about the ChromaBlur not working, does anyone have a comment on that?
There is an excellent tutorial in the August 2007 SCS newsletter that gives some great advice on using Chroma Key along with the Secondary Color Corrector, all within Vegas.
I'll check that out also. edit- this unfortunately is only dealing with a problem with the screen. I feel sure the screen is not my problem as it is lit very evenly, doesn't have wrinkles etc...oh well I'm off to try the backlight suggestion from Keith
Thanks everyone,
Randy
Laurence wrote on 7/1/2008, 3:13 PM
There is an excellent tutorial in the August 2007 SCS newsletter that gives some great advice on using Chroma Key along with the Secondary Color Corrector, all within Vegas.

That is a good tutorial.
farss wrote on 7/1/2008, 3:36 PM
As your subject isn't moving why not take a photo of it with a digital still camera. That gives you more resolution and way better chroma sampling to work with. If you've got Photoshop or another photo editing tool then extracting the background will be much easier using that. Just save the image as a PNG file to preserve the alpha channel and bring it into Vegas. Job done.

I recently bought a cheap light box / cocoon of eBay. I shoot the objects against the supplied black background. Way better than using green / blue as there's no spill. Plus the light box gives me even lighting.

Bob.
Randy Brown wrote on 7/1/2008, 4:18 PM
Hey Bob,
I am only using dolls as a subject to set up for a greenscreen shoot I have scheduled in a couple of weeks. I do mostly corpoarte video that ordinarily involve (sometimes) many interviews...if I can get this working well then I'll be able to do some work here at my studio instead of shooting on location (and having to move the set several times).
Anyone have any comments on Serious Magic (pricey but looks muy cool)?
Thanks for the reply though Bob,
Randy
BTW, I haven't seen any suggestions as to the camera from talent distance in any of the tuts. So that I can record directly into Vegas Vidcap I'm only about only 6 feet from the dolls (my firewire is relatively short)...could that be a factor?
farss wrote on 7/1/2008, 5:09 PM
Ah OK. You get 10/10 for having the common sense to TEST something before you try to deal with it in post. You're miles ahead of a lot of people in this game :)

Ultra does an excellent job. I have it as part of Adobe's CS3 Premium Bundle. I don't think you can buy it as a standalone product anymore. CS3 does ship witha choice of several keyers including Keylight which gets rave reviews but it does have a lot of things you can / might need to twiddle.

Before you give up on Vegas's basic keyer there's some good advice above from others that you may have missed. You only need worry about getting a good key in the area immediately around the subject. The rest of the frame you can wrangle with a "garbage matte". Vegas has a number of was to create garbage mattes, the bezier mask in event pac/crop is the most direct.

Subject to camera distance shouldn't matter. Subject to screen distance does. The closer they are to the screen the more likely you are to have spill problems. Your screen should be evenly lit and 1 stop under the subject lighting. If your camera has zebras make use of them to check lighting and exposure. Camera to subject distance could have one minor impact. If the camera is a long way from the subject then you can thow the background out of focus, that may help.
Make certain your camera isn't adding gain. Gain = noise = hard time for the keyer.

Bob.
Jim H wrote on 7/1/2008, 5:30 PM
Randy,

Serious Magic was bought out by Adobe and Ultra2 is now only available as part of the CS3 package. :(
TheHappyFriar wrote on 7/1/2008, 7:07 PM
I installed and tried to load the avi but got an error stating : The video file could not be opened. You are probably missing a code

I just opened up a DV AVI no problems. Odds are you don't have a separate DV codec installed on your machine (vegas uses it's own). Here's one recommended in the cinegobs forums: [url=http://www.videohelp.com/tools/Cedocida_DV_Codec]
Randy Brown wrote on 7/2/2008, 6:29 AM
Bob said :Vegas has a number of was to create garbage mattes, the bezier mask in event pac/crop is the most direct.
I'll check that out my friend.
Make certain your camera isn't adding gain. Gain = noise = hard time for the keyer.
The camera (Canon XL1S) is set to manual with a -3 gain
If your camera has zebras make use of them to check lighting and exposure.
That's an excellent idea but they are indeed evenly distributed when I turn up the gain high enough to see the zebras
Thanks very much Bob!

Jim said: Serious Magic was bought out by Adobe and Ultra2 is now only available as part of the CS3 package. :(
jeez, it seems Adobe wants it all

Happy Friar said: just opened up a DV AVI no problems. Odds are you don't have a separate DV codec installed on your machine (vegas uses it's own). Here's one recommended in the cinegobs forums: www.videohelp.com/tools/Cedocida_DV_Codec
Thank you sir, I'll check that out too.

In my last test yesterday, after applying 3 point lighting to the dolls (and 2 softboxes on the screen) I may have usable results but not sure how it would look with movement. I plan to shoot real, moving, people today (my daughter and her friend) and will report back with the results.
You have all been very helpful and I appreciate it very much!!
Randy
farss wrote on 7/2/2008, 6:36 AM
Get a Barbie doll with blonde hair. Use a fan to blow it around. If you can pull a good key off that you're doing very well.

Bob.

Rory Cooper wrote on 7/2/2008, 9:17 AM
Vegas chroma keyer is a battle

If you first go to sec color correct and use sat greens and then chroma key your green, the results are better. if Vegas put the saturate green with the keyers this would make sense

Fortunately I have Boris as a plug and that is more adjustable

If I use Particleillusion I do the clip on a flat black for example an explosion
Then in Vegas double the clip up make the top parent multiply that and add mask generator pop your high in and low in sliders
Leave the bottom clip basically you saturate the colors from the bottom layer into the top which already is a perfect gradient alpha
The results are exact you can never match that with a chroma keyer even in Boris
TheHappyFriar wrote on 7/2/2008, 9:58 AM
If I use Particleillusion I do the clip on a flat black for example an explosion

incase you didn't know, in PI you can render as uncompressed AVI with alpha channel & a png with alpha channel. :)

But I many times do the same thing: use the chroma key to make a mask clip & then apply that via child track.