diff --git a/source b/source
index 6b6d78e0706..fb6504317a8 100644
--- a/source
+++ b/source
@@ -34595,7 +34595,8 @@ interface <dfn>MediaError</dfn> {
 
  <dd>
 
-    <p>Can be set to false to have the <span>media resource</span>'s audio pitch change up or down correspondingly to the <code data-x="dom-media-playbackRate">playbackRate</code> instead of using pitch-preserving algorithms. This is useful for aesthetic and performance reasons. Default: true.</p>
+    <p>Returns true if pitch-preserving algorithms are used when the <code data-x="dom-media-playbackRate">playbackRate</code> is not 1.0. The default value is true.</p>
+    <p>Can be set to false to have the <span>media resource</span>'s audio pitch change up or down correspondingly to the <code data-x="dom-media-playbackRate">playbackRate</code>. This is useful for aesthetic and performance reasons.</p>
 
    </dd>
 
@@ -34847,10 +34848,10 @@ interface <dfn>MediaError</dfn> {
   being set by script or by being changed directly by the user agent, e.g. in response to user
   control) the user agent must <span>queue a task</span> to <span data-x="concept-event-fire">fire
   an event</span> named <code data-x="event-media-ratechange">ratechange</code> at the <span>media
-  element</span>.</p>
+  element</span>. The user agent must process attribute changes smoothly and must not introduce any perceivable gaps or muting of playback in response.</p>
 
   <p>The <dfn><code data-x="dom-media-preservesPitch">preservesPitch</code></dfn> attribute, on
-  getting, must return TODO. On setting, TODO.</p>
+  getting, must return true if a pitch-preserving algorithm is in effect during playback. On setting, the user agent must correspondingly switch the pitch-preserving algorithm on or off without any perceivable gaps or muting of playback.</p>
 
   <hr>
 
@@ -120817,6 +120818,7 @@ INSERT INTERFACES HERE
   Ashley Gullen,
   Ashley Sheridan,
   Atsushi Takayama,
+  Attila Haraszti,
   Aurelien Levy,
   Ave Wrigley,
   Avi Drissman,