Allow level-id to be different in codec match

amendments.json

@@ -1242,5 +1242,16 @@
   "web-platform-tests/wpt#48361"
       ]
     }
+  ],
+  "codec-match-without-level-id": [
+    {
+      "description": "Two codecs are considered the same even if level-id is not",
+      "type": "correction",
+      "status": "candidate",
+      "difftype": "modify",
+      "id": 51,
+      "pr": 3023,
+      "testUpdates": "not-testable"
+    }
   ]
 }

base-rec.html

@@ -11174,6 +11174,7 @@ <h4 id="methods-8">
                 </ol>
 		</div>
 		<div id="codecmatch-algorithm"><!-- added as anchor to new algo in revised spec --></div>
+    <div id="codec-match-without-level-id"><!-- amendment to the codecmatch-algorithm --></div>
                 <div class="note" role="note" id="issue-container-generatedID-47"><div role="heading" class="note-title marker" id="h-note-47" aria-level="5"><span>Note</span></div><p class="">
                   If set, the offerer's codec preferences will decide the order
                   of the codecs in the offer. If the answerer does not have any

webrtc.html

@@ -11443,6 +11443,7 @@ <h2>
                   given two {{RTCRtpCodec}} dictionaries
                   <var>first</var> and <var>second</var> is as follows:
                 </p>
+                </div>
                 <ol class=algorithm>
                   <li>
                     <p>
@@ -11467,21 +11468,26 @@ <h2>
                     </p>
                   </li>
                   <li>
+                    <div id="codec-match-without-level-id">
                     <p>
                       If either (but not both) of <var>first</var>.{{RTCRtpCodec/sdpFmtpLine}}
                       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>. Two FMTP lines are the same as long as they convey the same
+                      information, including omitting parameters with well defined defaults or using
+                      different order. In this step, the user agent MUST NOT consider two FMTP lines
+                      different if "media format" is the same and only the highest complying bitstream
+                      level differs.
                     </p>
+                    </div>
                   </li>
                   <li>
                     <p>
                       Return <code>true</code>.
                     </p>
                   </li>
                 </ol>
-		</div>
                 <p class="note">
                   If set, the offerer's receive codec preferences will decide the order
                   of the codecs in the offer. If the answerer does not have any