diff --git a/media-source-respec.html b/media-source-respec.html
index f7e6a49..8e73ce5 100644
--- a/media-source-respec.html
+++ b/media-source-respec.html
@@ -2726,7 +2726,7 @@ <h2><dfn>BufferedChangeEvent</dfn> interface</h2>
       <pre class="idl">
         [Exposed=(Window,DedicatedWorker)]
         interface BufferedChangeEvent : Event {
-          constructor(DOMString type, optional BufferedChangeEventInit eventInitDict = {});
+          constructor(DOMString type, BufferedChangeEventInit eventInitDict);
 
           [SameObject] readonly attribute TimeRanges addedRanges;
           [SameObject] readonly attribute TimeRanges removedRanges;