title: Multi party video chat- Detect the peer speaker
body: <p>I have implemented the multiparty video chat (audio and video enabled)  and it is working fine. How can I figure out which peer is speaking and highlight a green icon besides that user.</p>
  
  <p>The onStreamAdded gets called only when a new stream is added but how do I track 
  who is speaking currently.</p>
  
  <p>Regards
  Raghav</p>