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Combining Key & Window


jan1
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I ran into an issue yesterday, and none of the operators seemed to do what I needed.

Here's the scenario: I'm keying a person in front of a textured background. The skin and background are very similar, so the key has to be just right. On the very edge of the frame the exposure dropped and there was some key noise. So what I was hoping is to combine a key and a shape in an 'OR' operation. The key would catch 99% of the background, and I would override the key on the frame edge with a shape. However, I needed the shape to include that area, not eliminate it. Kind of an inverse garbage matte. I've run into that scenario several times when I have super tight keys, where I can gain some wiggle room by overriding a noisy area.

I tried various combinations of inverting the shapes, outside mode in the keyer, and looking at both inside/outside grades in highlight mode. No luck,

I think the limitation is that all the variations of outside mode are always 'AND' operations, never 'OR' operations.

I was able to create a complex node tree - using separate color corrector nodes for the HSL and shape, then an channel operation or, and finally the actual color corrector that imports an external key. That's a lot of tree building as I have about 20 clips in the timeline of the same shot that all need this. And with this node tree I'm duplicating the initial color/uni color 3 times, so if I need to make revisions I need to do that 3 times, unless I build the link node in.

Also, there are so many keyer nodes, but no HSL standalone. You have to use the color node and export. Same for just a simple alpha shape. Granted in the end it's kind of the same thing....

Any ideas on how to do this easier?

image.png.3eabdc61d51cc08207dcccbb45d99df2.png

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If memory serves me right from school many years ago, An 'OR' can be simulated by a 'NOT(NOT(A) AND NOT(B)), and while I can invert the shape, and I can take the outside, I'm missing the outer NOT to make this happen....

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OK, worked it out. Apologies for creating noise in the forum. Maybe it helps someone else down the road.

The easier solution is to create one vector in the color node for the shape. Then in a second vector do the HSL key and color correct. Enable the External Vector and select the previous vector with the 'Add' operation. That combines the inside shape with the HSL key. And it's all contained inside the color node, just spread across two vectors. But that's manageable in terms of timeline propagation.

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