Allow level-id to be different in codec match

webrtc.html

@@ -11472,7 +11472,9 @@ <h2>
                       and <var>second</var>.{{RTCRtpCodec/sdpFmtpLine}} are [= map/exist | missing =],
                       or if they both [=map/exist=] and <var>first</var>.{{RTCRtpCodec/sdpFmtpLine}}
                       is different from <var>second</var>.{{RTCRtpCodec/sdpFmtpLine}}, return
-                      <code>false</code>.
+                      <code>false</code>. In this step, the user agent MUST consider two FMTP lines
+                      identical if the "media format" is the same but the highest complying bitstream
+                      level differs.
                     </p>
                   </li>
                   <li>