hello, maybe give some more details ?
is it on the same machine?
on which desktop you try to do that? Windows? macOS? both?
now, that said, OBS is open source and so you can look at how they do it
that would be quite a heavy/hard ANE to produce
but then the problem is you say “I want to do like OBS”
and so I’m asking “are you sure you need the capturing/streaming like OBS?”
capturing (as a bitmap screenshot) the content of a specific window or screen rectangle, or even dealing with multiple monitors and other virtual desktops, just that, is already quite some work, but if you need the “video stream capture” then that become something much bigger
not impossible but not something you can YOLO over a a couple of week-ends
I don’t see some shortcuts to do that but again I’m not completely sure of what you’re trying to do
so there in the spirit of building software with ActionScript and AIR I would advice: have you a functional spec of what kind of features you need ?