isVisible = true;
Inner classes have visibility on all variables of outer classes, including the private ones.
That's why Processing's global variables work: they are actually members of the main class, and can be used from everywhere.

what about the other way?

if i have a hierarchy:
Master Class
 -Video
 -Audio
 -Capture

and I want to use a variable from Video in the Master Class

I want to initiate a constructor using an array which currently resides in the Video class

thanks for your help!:)

I realize my first answer might have been a bit off.
You wrote about a class hierarchy, but I answered as if the classes were just nested, ie. declared inside other classes.
If the relation is actually made with the extends keyword... the answer would be still the same (!), but for different reasons: sub-classes have access to all fields of parent classes, as long as they are not private.

Now, I feel that when you write hierarchy, in your second message, it is indeed about nested classes, which is the common usage in Processing. But since your questions are quite abstract, it is hard to tell.

Anyway, the answer is similar in all cases.
Say Video has an instance living in the video variable.
Then master class can access a variable of this class as: video.someVariable