i have a mask of a lion running from left to right. Then i would like to have this running lion to stay in the middle of my composition (like pinning the lion). How can i do that after masking this lion running from left to right without doing it frame by frame
I'm not sure how you have your composition set up, but it sounds like you could animate the position and/or anchor point to keep your mask in the center.
If the motion is reasonably linear, a few keyframes on the layer position should suffice. Otherwise try a stabilize track 8the old tracker!) with some features of the tiger as the tracking reference points...
Does this help?