• It's usual to send audio/video data in real time applications
  
• There are several server on the market able to stream data
   
  
  

• Accordingly to google WebRTC is a new way yo do real time communication on the web without using any plugin.
  
  
• WebRTC is a free, open project that enables web browsers with Real-Time Communications (RTC) capabilities via simple Javascript APIs.
  
  
• WebRTC API are available in Chrome 24+, Aurora (FF nightly build) and Opera 12+.
  
  
• Don't confuse WebRTC API and the the <device> API.

• Micrsoft will not implement WebRTC, it will go ahead with its standard named CU-RTC-Web
  
  
• CU-RTC-Web stays for Customizable, Ubiquitous Real Time Communication over the Web
  
  
• There is a strong debat about CU-RTC-Web and it seems MS has some good reason to go its own way
  
  
  • An RTC standard should provide information about the network quality
    
    
  • A standard cannot support only the VP8 video codec

• At the moment Apple doesn't have an official position on WebRTC
  
  
• What it’s doing with iMessage and FaceTime suggest it’s going its own way
  
  
• The rumors lead to think that Apple will add WebRTC to Safari at the very least once the specification is finalized

• It's an extension for
  
  
  • Safari
  • Firefox
  • Opera
  • IE9


• Source code available here https://code.google.com/p/webrtc4all/
  

• The APIs are standard and platform independent
  
  
• Using the SRTP protocol it's possible to create encrypted  audio/video communication
  
  
• Communication is more reliable because there is a direct connection between peers using NAT (Network Address Translation)
  
  
• The protocol is adaptive to the network conditions
  
  
• WebRTC can inter operate with communication systems using SIP, Jingle or PSTN 

1. Obtain a local media from the browser
   
   
2. Setup a connection between a browser and another peer
   
   
3. Attach media and data to channel opened between the peers

  navigator.getUserMedia({video: true, audio:true},
                          onStreamReady, onStreamError);

• The RTCPeerConnection API represents the core of WebRTC
  
  
• From a practical point of view the "peer" connection is able to connect two points over internet
  
  
• A connection can setup is performed using a configuration object containing the info to peer two clients

function createPC() {       
	pc = new RTCPeerConnection( configuration);         
	// send any ice candidates to the other peer       
	pc.onicecandidate = function (evt) {               
	   signalingChannel.send(JSON.stringify({"candidate": evt.candidate }));
	};         
	// process addition of remote streams       
	pc.onaddstream = function (evt) {handleIncomingStream( evt.stream);}; 
}

• Audio / Video Call (1:1)
  
  
• Multiple Peer Connection 
  
  
• Audio / Video Conference (google app engine)
  

• A way of running JavaScript outside the browser
  
  
• A wrapper around the V8 Google Chrome JavaScript runtime that provides additional API
  
  
• Buffer
• FileSystem
• Many others...
  
  
• A server side event driven environment

var http = require('http'); 
http.createServer( function (req, res) { 
	
	res.writeHead( 200, {' Content-Type': 'text/ plain'}); 
	res.end(' Hello World!\n'); }).listen( 8500, "127.0.0.1"); 
	
console.log('Server running at http://127.0.0.1:8500/');

• Easy to start using the built-in Read Evaluate Print Loop tool
  
  
• Because it's more scalable compared to a classical server side environment
  
  
• Because the learning curve is easy for a web developer
  
  
• Because it can be used to run UI app on the desktop too https://github.com/rogerwang/node-webkit (app runtime based on chromium and node.js)
  
  
• Because a node.js app serves up a base presentation document, manipulates it with Javascript, get more data from the server and do it again! (single page apps!)

• It's a node module available on the npm module registry https://npmjs.org/package/webrtc.io
  
  
• It's an abstraction layer for WebRTC

 npm install webrtc.io

• var app = require('express')();
  
  
• var server = require('http').createServer(app);
  
  
• var webRTC = require('webrtc.io').listen(server);
  
  
• server.listen(port);
  
  

• webRTC.rtc.on('connect', function(rtc) {
    //Client connected
  

  });

  
  
• webRTC.rtc.on('chat_msg', function(data, socket) {
  // Chat message handler
  }
  
  

Behind the scene there is a node.js WebSocket implementation (http://einaros.github.com/ws/)