title: How to use kurento-media-server for audio only stream?
body: <p>I want to have only audio stream communication between peers , I changed the parts of kurento.utils.js to get only audio stream via getusermedia 
  but it's not working<br>
  I used this example <a href="https://github.com/Kurento/kurento-tutorial-node/tree/master/kurento-hello-world" rel="noreferrer">node-hello-world</a> example
  </p>
  
  <pre><code>WebRtcPeer.prototype.userMediaConstraints = {
      audio : true,
      video : {
          mandatory : {
              maxWidth : 640,
              maxFrameRate : 15,
              minFrameRate : 15
          }
      }
  };
  </code></pre>
  
  
  
  <p>to </p>
  
  <pre class="lang-js prettyprint-override"><code>WebRtcPeer.prototype.userMediaConstraints = {
      audio : true,
      video : false
  };
  </code></pre>
  
  
  
  <p>is it possible use kurento service for only audio stream?</p>