is it possible to limit the max and min values of keyframes?

[iklimd]

dear community,

For a project i am trying to stabilize faces from various videos. I analyzed the faces with detailed face tracking, then used stabilizator. I attached the keyframes from face tracking to the stabilizator's track points.

i prefer a stabilization including scaling, because my subjects are changing their distance to the camera from time to time, but there are many points that the tracking does not work fluently, and extraordinary zoom ins and zoom outs occur. Is there a way, to control it with a function, saying that it limits to max scaling to 110 percent and min scaling to 90 percent? I tried the smooth function, but even that had a limit

thanks a lot and best regards,

ik

[Jose Panadero]

You can do it using the clamp expression or even a conditional expression. There are some videos on youtube regarding the use of both expression. Take a look.

[iklimd]

thank you jose. the clam expression worked! is it possible touse two expressions at once? i would like to use both clamp and smoooth at once

[Rick Gerard]

Your workflow sounds a little convoluted. I use several different types of motion stabilizing all of the time. Most of the time, I use Mocha AE to do the motion stabilizing. When the shot is stabilized and the composite or other work is done, it is easy to put all or some of the movement back in the shot. The most efficient workflow depends on the shot and what you need to do with the shot.

If you can share a typical shot that is giving you problems I would be glad to suggest a more efficient workflow. Detailed Face Tracking is probably the hast tool I would use to do what I think you are describing. 

[iklimd]

hi rick, thanks for your response. after reading your message i started to experiment with mocha ae. now i am realizing that the best way would be to track in a planar way using corner pins (rather than face tracking) and stabilize it. but still, even with mocha ae, i am having some difficulties. there are some moments where the subjects touch their face with their hand, or turn their head around.

the project is about the a theater piece with digitalized masks for a "masquerade ball". (around 70 minutes with more than 60 cuts, video pieces) so the faces from the films should be stabile, the mouth can move around, but the chin, eyes, forehead etc. should be stabilized. as in the first image, i would like to cut out everything except the faces from the films. face tracking can do that. but as you are suggesting, using the data from face tracking to stabilize the motion is a bad option. the results are not good enough.

do you have suggestions to use mocha ae in a similar way, or can i bring the tracked faces to mocha and use planar stabilization with that? any suggestions for the workflow? stabilized faces are my priority, meaning that i can also make an ellipse mask around the stabilized video, if the cut out option is more difficult.

your help is much appreciated, greetings from vienna!

iklim