Don't try to infer the media format from the content only if contentSize is 0

midp/media.js

@@ -372,7 +372,7 @@ Player.prototype.getBufferSize = function() {
 };
 
 Player.prototype.getMediaFormat = function() {
-    if (this.url === null || this.contentSize === 0) {
+    if (this.contentSize === 0) {
         return this.mediaFormat;
     }