diff --git a/index.bs b/index.bs
index 72b8d25..38db4e6 100644
--- a/index.bs
+++ b/index.bs
@@ -340,6 +340,7 @@ dictionary RTCEncodedVideoFrameMetadata {
     octet payloadType;
     sequence<unsigned long> contributingSources;
     long long timestamp;    // microseconds
+    unsigned long rtpTimestamp;
 };
 </pre>
 
@@ -383,6 +384,16 @@ dictionary RTCEncodedVideoFrameMetadata {
       {{VideoFrame/timestamp}} for raw frames which correspond to this frame.
         </p>
     </dd>
+    <dt>
+        <dfn dict-member>rtpTimestamp</dfn> <span class=
+            "idlMemberType">unsigned long</span>
+    </dt>
+    <dd>
+        <p>
+            The RTP timestamp identifier is an unsigned integer value per [[RFC3550]]
+            that reflects the sampling instant of the first octet in the RTP data packet.
+        </p>
+    </dd>
 </dl>
 
 
@@ -393,7 +404,6 @@ dictionary RTCEncodedVideoFrameMetadata {
 [Exposed=(Window,DedicatedWorker), Serializable]
 interface RTCEncodedVideoFrame {
     readonly attribute RTCEncodedVideoFrameType type;
-    readonly attribute unsigned long timestamp;
     attribute ArrayBuffer data;
     RTCEncodedVideoFrameMetadata getMetadata();
 };
@@ -410,16 +420,6 @@ interface RTCEncodedVideoFrame {
             sent or received.
         </p>
     </dd>
-
-    <dt>
-        <dfn attribute>timestamp</dfn> <span class="idlMemberType">unsigned long</span>
-    </dt>
-    <dd>
-        <p>
-            The RTP timestamp identifier is an unsigned integer value per [[RFC3550]]
-            that reflects the sampling instant of the first octet in the RTP data packet.
-        </p>
-    </dd>
     <dt>
         <dfn attribute>data</dfn> <span class="idlMemberType">ArrayBuffer</span>
     </dt>
@@ -474,6 +474,7 @@ dictionary RTCEncodedAudioFrameMetadata {
     octet payloadType;
     sequence&lt;unsigned long&gt; contributingSources;
     short sequenceNumber;
+    unsigned long rtpTimestamp;
 };
 </pre>
 ### Members ### {#RTCEncodedAudioFrameMetadata-members}
@@ -517,13 +518,21 @@ dictionary RTCEncodedAudioFrameMetadata {
             Comparing two sequence numbers requires serial number arithmetic described in [[RFC1982]].
         </p>
     </dd>
+    <dt>
+        <dfn dict-member>rtpTimestamp</dfn> <span class="idlMemberType">unsigned long</span>
+    </dt>
+    <dd>
+        <p>
+            The RTP timestamp identifier is an unsigned integer value per [[RFC3550]]
+            that reflects the sampling instant of the first octet in the RTP data packet.
+        </p>
+    </dd>
 </dl>
 
 ## <dfn interface>RTCEncodedAudioFrame</dfn> interface ## {#RTCEncodedAudioFrame-interface}
 <pre class="idl">
 [Exposed=(Window,DedicatedWorker), Serializable]
 interface RTCEncodedAudioFrame {
-    readonly attribute unsigned long timestamp;
     attribute ArrayBuffer data;
     RTCEncodedAudioFrameMetadata getMetadata();
 };
@@ -531,15 +540,6 @@ interface RTCEncodedAudioFrame {
 
 ### Members ### {#RTCEncodedAudioFrame-members}
 <dl dfn-for="RTCEncodedAudioFrame" class="dictionary-members">
-    <dt>
-        <dfn attribute>timestamp</dfn> <span class="idlMemberType">unsigned long</span>
-    </dt>
-    <dd>
-        <p>
-            The RTP timestamp identifier is an unsigned integer value per [[RFC3550]]
-            that reflects the sampling instant of the first octet in the RTP data packet.
-        </p>
-    </dd>
     <dt>
         <dfn attribute>data</dfn> <span class="idlMemberType">ArrayBuffer</span>
     </dt>