How to lumakey in Vegas Video 5?

[gpvillamil]

Well, I've been struggling with this one for a while. I'm trying to get a lumakey effect in Vegas Video 5.

Chromakey is a piece of cake - drag from the effect pool to the track, and bingo.

There is also a mask generator effect, which works on luma, but removes all color.

All I want to do is a hard-cut lumakey effect - make the black parts transparent.

How do you do this in Vegas Video 5?

[gpvillamil]

Anyone know anything about this? Or am I totally barking up the wrong tree?

[seex]

croma key is a lumakey that also registers colour values, if you focus the colour to black or white you got a lumakey. I dont actualy know how to do this in vegas but its the logic.

[gpvillamil]

Thanks, that's what I tried:

However, using chromakey with colors focused to black and white didn't quite work - I want to key out dark red, dark blue and dark green, for example. The Vegas chromakey, when set to a black/grey value will *only* key out around that.

What I am thinking of doing is building a luma mask from the source clip, and then layering it under the source clip. It should work, but it seems somewhat complicated, relative to the ease of chromakeying.

[seex]

hmm, i think you need to invert the treshold ramp.

If you want to key out three colours you need to use three filters, thats how it works in After Effects.

[mondo]

i used the colour corrector filter with teh chroma key filter and eyedropped the colour i needed blanked out - worked fine

[gpvillamil]

Right, here's something that worked.

Basically, I duplicate each track that I want to work with, except the bottom-most one. For example, if I want to layer 3 videos, with the dark parts of each one being transparent, I would make 5 tracks: 2 for layer 1, 2 for layer 2 and 1 for layer 3 (which is the bottom).

Make the second track of each pair a compositing child of the first track. Apply a threshold effect to the track (if you want a hard cut effect), apply an invert effect if wanted, then apply the luminance mask. Change the compositing mode to Multiply (mask) or Cut (for a different effect). Repeat for each pair of tracks.

Mess with the threshold and luma in/out parameters until you get what you want. I found it handy to temporarily exaggerrate the color balance of each layer (eg make the top one red, next green, last blue) to see how much of each layer was showing through.

Still seems a bit Rube Goldberg to me, but it does give a lot of control over the masking.

[drmo]

i think you have done pretty much what is described in the manual.

pre vegas 5 i used to understand how to use parent and child compositing with mask generators.then that was definitly the way to do luma keying (or any other type of keying or maskin)

but now they have made it more flexible and i dont understand it anymore.
you're on the right track though i figure.