you can do this using sourceRectAtTime expression. just link the appropriate parameters.
Thank you Roei Tzoref,
I tried with this one, but I put the expression on the scale of my pre-comp and liked like as the tutorial but it makes me a huge scaling...
I think it's because I link x and y like in the tutorial, and he use a shape rectangle so it's working but I'm using a pre-comp so in the scale there is no x and y...
Here is my project if you want to help me :-)
thank you very much
Well I put this :
And the scale of my pre-comp scale less bigger and it's look what I would like.
But I would like it keeps like 30px left and right of my text...
Like my guide layer "Border info"
Add +60 (or whatever number you like) to both x and y.
For further control you could create expression slider controls and then link the + amount to those slider controls.
Sorry for this issue. Did you ever find a solution? Please let us know if you have or if you still need help.