Difference Matte in Vegas 6 ?

bill31415 wrote on 8/29/2006, 12:56 PM
Is it possible to subtract a background from a video? The new Mac OS 10 (iChat) software does this, where you can film a few seconds of just the background, then it will remove it from your video (this assumes the camera is not moving). My video has a fairly blank background screen, which I was trying to remove, so I could drop in a new background. I saw some matte support in Vegas, but it looks like you use an eyedropper to select a background color to remove (perhaps for when using a green screen). I imagine a "difference matte" would be a kind of "poor man's chroma key". is this possible to do in vegas? I didn't really want to buy the greenscreen stuff if I could just subtract out an unchanging background.

Comments

bill31415 wrote on 8/30/2006, 4:33 PM
*bump* anyone?
Tim L wrote on 8/30/2006, 7:01 PM
I don't think we can do this in Vegas Movie Studio, but I think it probably can be done in the full version of Vegas.

In VMS, we only have two compositing functions: Multiply and Alpha. The full Vegas program has many more, including a Difference function.

I think (but I'm just guessing here) that this difference function could be used to composite the empty background track and the normal video track together to create a difference mask, then probably the Mask Generator effect would be used to clean up the mask, and finally the mask track would have to then be composited (using Multiply?) with the video track again to mask out the background and retain just the actor.

Note: This is a lots of guessing here on my part. You might get better info from the really smart guys over in the regular Vegas forum.

Tim L
bill31415 wrote on 8/30/2006, 9:56 PM
I bought Vegas 6 Platinum a few months ago, and am only now starting to play with it - I didn't realize there was a "pro" version. I will look into the full version. Thanks!
IanG wrote on 8/31/2006, 12:19 PM
Don't forget there's a new version of Vegas due out soon. Sony's upgrade deals are good, so it might be best to wait a few weeks if the full version is what you need.

Ian G.