add placeholder normative definition

source

@@ -32355,10 +32355,6 @@ interface <dfn>HTMLMediaElement</dfn> : <span>HTMLElement</span> {
       so that the author's controls can get away of the UA's
   -->
 
-  <!-- v2 features that already have experimental implementations:
-    * webkitPreservesPitch (for when playbackRate != 1.0)
-  -->
-
   <p><span data-x="media element">Media elements</span> are used to present audio data, or video and
   audio data, to the user. This is referred to as <dfn>media data</dfn> in this section, since this
   section applies equally to <span data-x="media element">media elements</span> for audio or for
@@ -34853,6 +34849,9 @@ interface <dfn>MediaError</dfn> {
   an event</span> named <code data-x="event-media-ratechange">ratechange</code> at the <span>media
   element</span>.</p>
 
+  <p>The <dfn><code data-x="dom-media-preservesPitch">preservesPitch</code></dfn> attribute, on
+  getting, must return TODO. On setting, TODO.</p>
+
   <hr>
 
   <p>The <dfn><code data-x="dom-media-played">played</code></dfn> attribute must return a new static
@@ -35113,8 +35112,10 @@ interface <dfn>MediaError</dfn> {
   data-x="dom-media-playbackRate">playbackRate</code> is so low or so high that the user agent
   cannot play audio usefully, the corresponding audio must also be <span
   data-x="concept-media-muted">muted</span>. If the element's <code
-  data-x="dom-media-playbackRate">playbackRate</code> is not 1.0, the user agent may apply pitch
-  adjustments to the audio as necessary to render it faithfully.</p>
+  data-x="dom-media-playbackRate">playbackRate</code> is not 1.0 and <code
+  data-x="dom-media-preservesPitch">preservesPitch</code> is true, the user agent must apply pitch
+  adjustment to preserve the original pitch of the audio. Otherwise, the user agent must speed up
+  or slow down the audio without any pitch adjustment.</p>
 
   <p>When a <span>media element</span> is <span>potentially playing</span>, its audio data played
   must be synchronized with the <span>current playback position</span>, at the element's