I've been using VLCJ to embed a number of media players in the same window - on Windows and Linux this works fine, because they can be out of process (which they need to be to be stable - in short because of native libraries underneath there's no way round this) and just alter the window in the other process.
However, does this out of process approach work on MacOS? The information I've found seems to suggest that it's not possible the way it is on Windows / Linux, but there's possibly some native call that can be made from one process to allow it to be controlled from another. Is this the case, and if so has anyone more information on any native code that might allow it to be the case? Apologies for the sparse information, I haven't got a Mac available to test on at the moment so can't run anything to try it out and see what happens!