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Old January 15th, 2009, 02:29 PM   #1
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Chromakeying vs Masking

Hi everyone,

Here's my question, I'm testing chromakeying for an upcoming project, here's the situation (look at the pictures) :

I'm filming a person in front of a greenscreen not wide enough (see picture CK-1)

I thought of going into the EVENT/ PAN CROP and reducing the width but this is what happened (see picture CK-2) notice the vertical lines on each side of the person

Then I thought of going into the EVENT/ PAN CROP and using the MASK option, but the same thing happened so I used the FEATHER TYPE option, set it to BOTH at 10% and this is what happened (see picture CK-3)

There must be something I'm not doing right.

Thanks.
Attached Thumbnails
Chromakeying vs Masking-ck-1.jpg   Chromakeying vs Masking-ck-2.jpg  

Chromakeying vs Masking-ck-3.jpg  

Last edited by Donald Blake; January 15th, 2009 at 02:32 PM. Reason: forgot pics
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Old January 15th, 2009, 03:03 PM   #2
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Here's what I got:
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Chromakeying vs Masking-ck-et.jpg  
Attached Files
File Type: veg ck-et.veg (8.5 KB, 144 views)
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Old January 15th, 2009, 03:15 PM   #3
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Edward,

I'm using Vegas 7,

I could'nt open your VEG file.
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Old January 15th, 2009, 03:20 PM   #4
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Here's what I did (I don't have Vegas 7 on this machine and don't want to turn the other one on right now)

Track 1: Your picture
Track 2: Background image

On your picture:
1. Used Pan/Crop masking to create a mask around the girl with NO feathering. This let me see the background image outside of that area.

2. Used ChromaKey on the green area close to the girl. Had to adjust the high and low settings to get things to look right.
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Old January 15th, 2009, 08:33 PM   #5
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Edward If you read my first post that's exactly what I did, I used the feather option because It came out like this (see CK-4.jpg)

I think it's not a chromakey problem, I don't have any trouble adjusting highs and lows to get the look right.

I think it's a masking issue, If i remember right I already had this trouble masking on another project.

What version are you using Edward? could that be it?
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Chromakeying vs Masking-ck-4.jpg  
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Old January 16th, 2009, 12:07 AM   #6
 
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Donald, it appears you've got a track motion shadow enabled, for starters? Or did you do that to better illustrate the key?
First, use the key to set your green. Then use the mask to cut her out. Be sure you don't have shadow on. Use the feathering both in/out.
We have a key that is too short for anyone much taller than 6', and have to often cut this, and have been using masking combined with keys since Vegas 5. I assure you, it works. But...you'll need to set the key first. Go ahead and key with the ugly sides. Then cut it out.
Make sure you're setting this to post, not pre.
HTH
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Last edited by Douglas Spotted Eagle; January 16th, 2009 at 12:08 AM. Reason: more info
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Old January 16th, 2009, 07:39 AM   #7
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Also, if you want to post YOUR VEG file, we can look at it to see where any issues may be.
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Old January 16th, 2009, 01:16 PM   #8
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Note that I haven't shot a chromakey yet, so anything I say is just from memory on what others have said or from what I see looking at your screen cap.

It looks like the subject is standing too close to the key screen and that the screen isn't hung or lit evenly enough. Some of the shadows on the wrinkles in the key are standing out.

When I tried my hand at the chromakey from your picture, the outside edge of her jeans too easily blended into the background because it was dark, as was that part of the chroma key cloth.
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Old January 16th, 2009, 04:07 PM   #9
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Like I said before jason, now I don't think it's a chromakeying issue, I already fixed the original problem (see CK_5) just by zooming in on the subjet and not having the need to mask because of the not wide enough greenscreen. But I still want to know why it happened.

I Had this problem before and there was no chromakey involved, just plain masking, An irregular line seems to apear around the mask (as you can see on CK-4 in my earlier post) the line is irregular.

I remember the last time this happened to me, I had filmed a field of white snow, and I wanted to mask out a dark rock in the middle of the field, so I masked it out, duplicated my track and chose the white snow on the side as background and the same thing happened, an irregular line appeared around my mask.

And to answer your question Douglas, no I did'nt add any shadowing of any kind in the track/motion section.

I should have had another Title to my original post "Masking problem" instead of "Chromakeying vs Masking"
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Old January 16th, 2009, 06:58 PM   #10
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Can you just post the VEG file? Then we can see exactly what you're doing and try to diagnose what setting is off.
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Old January 17th, 2009, 01:36 AM   #11
 
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Donald, try dropping a Chromablur on the event, and set it to "Pre" by toggling the little triangle in the plugin timeline head.
Set blur to 2.0.

If you still are struggling, do a framegrab PNG at Best/Full, email it to me, and I'll see if I can mask it for you.
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Old January 17th, 2009, 12:53 PM   #12
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You really shouldn't have to mask it, should you? If the green screen is evenly lit, subject is away from the green screen and casting no shadows, all should be good, right?

Question: When you cropped, did you ensure the aspect ratio was maintained?

I see the results, but I don't understand why it is effecting the image the way it is.

Could this be caused by the green screen being unevenly lit? (looking at the first pic)

I am very curious to find out what remedy was made....please keep us posted.

Good luck.
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Old January 17th, 2009, 01:01 PM   #13
 
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Masking can be necessary for any number of reasons, one of them being that he's got empty space behind the key that is in the shot. Another might be an unevenly lit key. Another might be that a boom mic fell into the shot.
Donald, did you try Chromablur yet?
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Old January 17th, 2009, 01:33 PM   #14
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Here's my VEG file

Ok guys, so I'm finally posting my VEG file so you can see for yourself.
The 2.7m WMV file wont load because it's HD, If you want it I can send it to you by e-mail, just let me know, that way you'll see exactly what I see...

Edward, sorry if it took some time I had to make another VEG file because I had alot of other stuff on it.

Douglas, I added the chromablur, anyways see for yourself!

Michael, I now think it dosent have anything to do with chromakeying, read my earlier post.

Thanks.
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File Type: veg test video - dvinfo.veg (12.2 KB, 138 views)
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Old January 17th, 2009, 02:15 PM   #15
 
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The veg without the content doesn't work. Can you upload or email a single frame grab as suggested earlier?
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