Streaming Video with PHP?!?!
No way man, never gonna happen.
For streaming video you need a multi-threaded run-time process with the ability to read and write to a stream output buffer.
And PHP is not even close to having anything like that. Sure, you can pick apart a binary and read that out and even write back into it, I do that all the time with MP3 files, but for streaming video, you want Java my friend.
Java, yes Java. You can write a tidy little Java Servlet to act as a multi-user server and then route the streams to who ever is on that server, which they can then view via a Java Applet.
And Don't get too hasty here either, because that's no small task, just writing that servlet is going to be lots of work. Muchless getting the servlet to do anything with active streaming.
And then the Applet on top of that?
Wow, that's a tall order my friend.
And that's just to send a stream from the server to the client. That applet will have to be able to tap ito any number of vid-cap cards on the client machine and send back the video/audio data so you can stream that back to the user on the other end.
Then you start looking at bandwidth costs
for all that streaming and then you start thinking, wow.. maybe this could be peer to peer... which is a whole nother load-o-fun unto itself.
But, hey... don't let me talk you out of it if you feel up for the task.