Real-time screensharing to Java app (localhost)

Question

I am looking for a way to add an overlay to a running Windows game, like OBS (a game streaming application, used for Twitch).

I though about using the Robot class to take 25/30 screenshots every seconds and display them, but I'm not sure that's the right solution..

So my question is the following: How can I screenshare a running app to a Java application (localhost, same computer), in order to add an overlay in front of it ?

EDIT: I tried using VLC Streaming but that makes the computer really laggy (i7/8Gb)... I tried with FFMpeg too, using screen-capture-recorder and gdigrab, the computer was not laggy, but the video drops like 5/10 FPS in real-time.
In FFMpeg, I used the following command : ffplay -f dshow -f gdigrab -i title="<NAME>" -framerate 30.

I would like to have a 25/30 FPS with a gaming computer (i7/8Gb)..

Answer 1

Try java-screen-recorder, it is a simple screen capturer and converter. It is not very cpu/gpu consuming. Solution based on java.awt.Robot and repeated capturing of the screen.

Answer 2

I once developed SimRat (A simple screen sharing app like Teamviewer) using Robot & Corba. You might be able to get a basic idea looking at the code. This is not the best possible way to implement screen sharing. Java RMI would be helpfull for you.