How to apply plugins only on masks?

Eugenia wrote on 4/1/2008, 9:34 PM
I would like to isolate a certain object from my clip (e.g. a cat) using the pan/crop's "mask" tool and then apply a certain plugin to it only, while leaving the rest of the scene untouched by the plugin. So I use two tracks, with the identical video on them, one has the mask in "Alpha" composite mode, and the second track has the normal video. Also, because the mask tool will be animated via keyframes, I need the plugin to "follow" the movement too. So, I move my mask around, per keyframe, to match my moving object.

Is there another way to do this? I would like to be using a single video track you see, instead of two to apply my plugin locally. Is this possible?

Comments

farss wrote on 4/1/2008, 10:17 PM
As far as I know no. You have to use two video tracks.

Bob.
Grazie wrote on 4/1/2008, 10:47 PM
If you want a "single track" just import THIS section as a Nest. Done. G
Eugenia wrote on 4/1/2008, 11:01 PM
Thank you for the replies. I think this can be "easily" simplified in the editor. On each plugin window, there is this arrow icon on the left of the timeline. There, you can click the arrow to make it look left and right. They could change that to be a drop-down option box instead, and add a new option that reads "apply to mask only". Additionally, the Path Mode in the pan/crop tool can have an additional option called "neutral". This way, you can have a mask on your main track, and still see the full video on your window (instead of just the mask or around the mask), and yet, have the mask only be recognized in that mode for the plugins windows. Not sure if I make any sense. :)
farss wrote on 4/2/2008, 1:33 AM
Well yes, it makes sense, but.

The effect of that arrow is to control if the mask is applied before or after the FX. Many cases that doesn't matter, others it does.

Compositing and controlling how it works is a very tricky business and one I've very glad I don't even have to think about how to code.

Consider applying the Gaussian Blur FX and a mask.

Simplest case. You blur the frame and cut it out with the mask leaving an edge defined by the mask.

Slightly more complex. You cut out the frame and then blur the result so the masked area blurs outside the frame. Not really very natural though.

Really complex. You cut out the frame with the mask and blur the result into what it's being composited into e.g. the result of the composite of all the tracks below...or maybe just the track below.

I know all that sounds like geek speak but they're all valid creative choices and have their place in the scheme of things. Implementing all those choices ins't easy and then getting the users to get a grip on how to use them is another matter. I know you only asked for something fairly simple. But then someone else wants another simple thing and you can end up with a major level of complexity being added. If you want to get a feel for how messy it all gets try yo fathom Photoshop's compositing, I still don't know about 90% of it although I can do what I need to get done with it. The rest is just too much for me so I'd send that part out to an expert.

Bob.
busterkeaton wrote on 4/2/2008, 5:42 AM
It seems like you figured out how to do this using two tracks, what's the benefit of using a single track?