diff --git a/index.bs b/index.bs
index 5c69e20..88b272c 100644
--- a/index.bs
+++ b/index.bs
@@ -406,6 +406,7 @@ interface RTCEncodedVideoFrame {
     readonly attribute RTCEncodedVideoFrameType type;
     attribute ArrayBuffer data;
     RTCEncodedVideoFrameMetadata getMetadata();
+    undefined setMetadata(optional RTCEncodedVideoFrameMetadata metadata = {});
 };
 </pre>
 
@@ -440,6 +441,16 @@ interface RTCEncodedVideoFrame {
             Returns the metadata associated with the frame.
         </p>
     </dd>
+    <dt>
+        <dfn for="RTCEncodedVideoFrame" method>setMetadata()</dfn>
+    </dt>
+    <dd>
+        <p>
+            Sets a new metadata that would be associated with the frame. Only allowed to change the fields
+	    frameId, dependencies and rtpTimetsamp in the RTCEncodedVideoFrameMetadata. All other changes
+	    are not allowed and should return an error.
+        </p>
+    </dd>
 </dl>
 
 ### Serialization ### {#RTCEncodedVideoFrame-serialization}
@@ -533,6 +544,7 @@ dictionary RTCEncodedAudioFrameMetadata {
 interface RTCEncodedAudioFrame {
     attribute ArrayBuffer data;
     RTCEncodedAudioFrameMetadata getMetadata();
+    undefined setMetadata(optional RTCEncodedAudioFrameMetadata metadata = {});
 };
 </pre>
 
@@ -558,6 +570,16 @@ interface RTCEncodedAudioFrame {
             Returns the metadata associated with the frame.
         </p>
     </dd>
+    <dt>
+        <dfn for="RTCEncodedAudioFrame" method>setMetadata()</dfn>
+    </dt>
+    <dd>
+        <p>
+            Sets a new metadata that would be associated with the frame. Only allowed to change
+	    the rtpTimetsamp field in the RTCEncodedAudioFrameMetadata. All other changes are
+	    not allowed and should return an error.
+        </p>
+    </dd>
 </dl>