stringify(cbObject.source));

     console.log("source.x : " + cbObject.source.x);
     console.log("source.y : " + cbObject.source.y);
     console.log("source.width : " + cbObject.source.width);
     console.log("source.height : " + cbObject.source.height);

     // Do something
        ...
  }

  function failureCb(cbObject) {
     var errorCode = cbObject.errorCode;
     var errorText = cbObject.errorText;
     console.log ("Error Code [" + errorCode + "]: " + errorText);
  }

  var video = new Video();