--- a/ttml10-sdp-us/Overview.html	Thu Sep 20 17:22:50 2012 +0800
+++ b/ttml10-sdp-us/Overview.html	Thu Sep 20 17:31:03 2012 +0800
@@ -1408,6 +1408,7 @@
 <td>&#160;</td>
 </tr>
 </table>
+<p>Note: Use of the #frameRateMultiplier feature is optional in a document (see <a href="#Features_in_TTML_1.0_Used">Features in TTML 1.0 Used in This Profile</a>).</p>
 </section>
 <section class='Core_Constraints'>
 <h4>Constraints</h4>