Universal maximise window function (independent of player)

Hi.

I have a flash file with a mix of embedded video and streaming video. Lots of different video in the file.

The video window is 720x400 in a flash file window of size 980 x 720.

I am wondering would it be possible to have a universal function which would maximise the 720 x 400 window (maintain proportions) and keep it there through all video changes until the reverse function was chosen?

I’m fairly new to AS3. Have read a lot but can’t figure out how to do this. Maybe I’m just being dumb and missing something? Any help appreciated.