+            # DRM-protected video, cannot be decrypted
+            if f.get('fileExt') == 'wvm':
+                continue
+            if not f.get('fileExt'):
+                # QT indicates QuickTime; some videos have broken fileExt
+                if f.get('containerFormat') == 'qt':
+                    f['fileExt'] = 'mov'
+                else:
+                    f['fileExt'] = 'mp4'