Mask or garbage matte?
Posted: Mon, 21st Apr 2008, 4:22pm
Post 1 of 5
-----> Warning! N00b alert! <-----
I have a video sequence that I put together in Vegas 8 and rendered as an avi. The video was shot from 2 camera locations (one for each character in the dialogue), both in front of a green screen, and cut together into a sequence. I am importing them into Visionlab to do my keying and FX.
The problem is that one of the sequences has a good chunk of the side of the video that wasn't covered by the green screen. I want to mask or matte it out, but when I do, it masks the entire video and not just the frames I want. Which should I use, as mask or a matte, and how do I tell a mask or garbage matte to "turn on" on frame X and "turn off" on frame Y, then "turn on" again on frame XX and "turn off" again on frame YY?
Is that as clear as mud? Do I need to provide any more specific information?
Thanks for any wisdom you can impart onto this neophyte.
Posted: Mon, 21st Apr 2008, 5:35pm
Post 2 of 5
Yup, a matte will be what you want to use, as a mask is seperate from the video, I.e if you move it it will mask the same area of the canvas, and the mask will not travel with the video.
My method for this sort of thing is just moving the garbage matte as you want, go through your frames, by default it will mask the entire clip, but if you keyframe it to move when you need it. As in, move it frame by frame, one frame its there, next, its out of the frame. So this may, sorry, will be tedious if you need to do many frames.
Now I think thats what you want, but I'm not sure.
Posted: Mon, 21st Apr 2008, 5:46pm
Post 3 of 5
Great info. Thanks!
Sounds like it will be tedious. Do you think it would be easier to slice the original video back up, matte the segments I need matted and re-assemble it again? That sounds to me like a faster way than going frame by frame in this instance.
Posted: Mon, 21st Apr 2008, 6:17pm
Post 4 of 5
Yes, thats the best way to do it, export the individual shots from vegas and do them by themselves, then re-assemble the shots in vegas. Or if you are just moving the garbage matte from shot to shot (As i think you've already exported the whole sequence) you can easily chop it up in visionlab with the slice tool, I think thats what you mean anyway though, this eliminates the need for any keyframes to be set at all. Huzzah!
(unless you're footage is very shakey, in which case invest in a tripod)
Posted: Tue, 22nd Apr 2008, 8:42am
Post 5 of 5
You simply need to draw the garbage matte around the keyed subject, then hit the 'invert' button. This will get rid of everything OUTSIDE the area you drew.
You can't turn gmattes on or off, but the best thing is to simply drag them off the canvas when they're no longer of use.