I think the simplest impl. would be to use RTMP for the
multicast of the person that wants to be seen and heard by everyone
and RTMFP for the voice feedback of the viewers.
But there sure are multiple ways to do it.
i would prefer udp/rtmfp over rtmp/tcp b'coz wen over tcp it
may create aditional latency issues coz it waits for the lost
signals to be retransmitted each time an error or drops occur,
which is not ideal for a real time process like a live chat or
something .... so i would go with udp rather than tcp