Problem with chroma blur,chroma key and pan

Daniel Z. wrote on 8/7/2005, 3:26 PM

Hi everyone,

i just encounter a difficulty that really annoy me. Let me explain it by giving you an example.

Let's take the original image: http://zuwala.free.fr/OriginalImage.png
I use pan to move the image : http://zuwala.free.fr/ImageBeforeChromaKey.png
with a green background.

Now i want to use chroma key, i show you the resulting image if i apply chroma blur before or not.

http://zuwala.free.fr/ImageAfterChromaKeyWithChromaBlur.png
http://zuwala.free.fr/ImageAfterChromaKeyWithoutChromaBlur.png

You can notice that when i use chroma blur (that i need to soften the edges), there is a border all around the image that ruined the chroma key. If i use a mask, i will get the same border corresponding to the mask.

So anyone has a solution? Did i miss something?

Comments

Coursedesign wrote on 8/7/2005, 4:14 PM

This problem occurs in many apps, not just Vegas.

I'm sure somebody has a simpler way, but in the meantime just use a "garbage matte" (another mask) to get rid of the border.

Daniel Z. wrote on 8/7/2005, 5:14 PM

This problem could be solved if there was a way to tell to Vegas to apply the mask after applying the fx. That way i could be free of any "border".
Any idea?

PS: i'm not sure i understand what you suggest Coursedesign

JohnnyRoy wrote on 8/7/2005, 5:28 PM

> PS: i'm not sure i understand what you suggest Coursedesign

A Garbage Matte is a mask used to remove... well... garbage! Stuff you don’t want. In your case you could mask out the border by adding a mask in the Pan/Crop settings or use a cookie cutter FX on the event, or adding another piece of media above it that’s green, or any number of ways.

~jr

Daniel Z. wrote on 8/7/2005, 5:43 PM

ok i see, but:

using mask creates other borders.
using cookie cutter is really painfull (do not move with pan/crop).

I'm looking for a fast solution, because i use this effect really often.

Coursedesign wrote on 8/7/2005, 6:40 PM

using mask creates other borders.

Not if you don't use blur on this mask, and there is no reason you should.

Daniel Z. wrote on 8/8/2005, 1:57 AM

>using mask creates other borders.
>Not if you don't use blur on this mask, and there is no reason you should.

That's what i get if i use a mask on the event i want to chroma key.

http://zuwala.free.fr/ImageBeforeChromaKeyWithMask.png
http://zuwala.free.fr/ImageAfterChromaKeyWithChromaBlurAndMask.png

And there is still the borders. But may be you think applying the mask on something else?

jaegersing wrote on 8/8/2005, 3:04 AM

Hi Daniel. Have you tried adjusting the Low Threshhold in the Chroma Key setup window?

Richard Hunter

Daniel Z. wrote on 8/8/2005, 3:24 AM

Hi Richard,

well i could adjust the threshold in this simple example, in order to do not have the borders anymore. But in more complicated exemple (with video), the threshold is already adjust in order to have a good chroma key, so i can't move it again to remove the "borders".