Add profile-level-id to make mobile Chrome happy

src/main.c

@@ -53,11 +53,17 @@ on_offer_created (GstPromise *promise, GstElement *webrtcbin)
 {
   GstWebRTCSessionDescription *offer = NULL;
   gchar *sdp;
+  GstSDPMedia *media;
 
   gst_structure_get (gst_promise_get_reply (promise),
       "offer", GST_TYPE_WEBRTC_SESSION_DESCRIPTION, &offer, NULL);
   gst_promise_unref (promise);
 
+  media = (GstSDPMedia *) gst_sdp_message_get_media (offer->sdp, 0);
+
+  gst_sdp_media_add_attribute (media, "fmtp",
+      "96 packetization-mode=1;profile-level-id=42e01f");
+
   g_signal_emit_by_name (webrtcbin, "set-local-description", offer, NULL);
 
   sdp = gst_sdp_message_as_text (offer->sdp);