work around https://code.google.com/p/webrtc/issues/detail?id=3807

libs/strophe/strophe.jingle.adapter.js

     }
     if (constraints.video) {
         constraints.video.optional.push(
-            {googNoiseReduction: true}
+            {googNoiseReduction: false} // chrome 37 workaround for issue 3807, reenable in M38
         );
         if (um.indexOf('video') >= 0) {
             constraints.video.optional.push(