--- a/media-source/media-source-respec.html	Fri Jun 13 12:47:06 2014 -0700
+++ b/media-source/media-source-respec.html	Fri Jun 13 12:54:01 2014 -0700
@@ -1026,7 +1026,15 @@
         <dd>
           <p>Specifies the default values to use if kind and/or language information is not available in the
             <a def-id="init-segment"></a> when the <a def-id="init-segment-received-algorithm"></a> needs
-            to create track objects.</p>
+            to create track objects. This attribute is initially set to an empty <a>TrackDefaultList</a> object.</p>
+          <p>On getting, Return the initial value or the last value that was successfully set.</p>
+          <p>On setting, run the following steps:</p>
+          <ol>
+            <li>If this object has been removed from the <a def-id="sourceBuffers"></a> attribute of the <a def-id="parent-media-source"></a>, then throw an
+              <a def-id="invalid-state-err"></a> exception and abort these steps.</li>
+            <li>If the <a def-id="updating"></a> attribute equals true, then throw an <a def-id="invalid-state-err"></a> exception and abort these steps.</li>
+            <li>Update the attribute to the new value.</li>
+          </ol>
         </dd>
       </dl>
 
@@ -2489,6 +2497,7 @@
                 <li>Bug 25999 - Change appendWindowStart assignments to reference presentation start time.</li>
                 <li>Bug 26000 - Make it explicit that SourceBuffer.remove() throws an exception if duration equals NaN.</li>
                 <li>Bug 25846 - Update end of stream algorithm to invoke the append error algorithm on decode errors.</li>
+                <li>Bug 25850 - Specify SourceBuffer.trackDefaults initial value and setter/getter behavior.</li>
               </ul>
             </td>
           </tr>

--- a/media-source/media-source.html	Fri Jun 13 12:47:06 2014 -0700
+++ b/media-source/media-source.html	Fri Jun 13 12:54:01 2014 -0700
@@ -406,7 +406,7 @@
   </p>
   <h1 class="title p-name" id="title" property="dcterms:title">Media Source Extensions</h1>
   
-  <h2 property="dcterms:issued" datatype="xsd:dateTime" content="2014-06-14T02:45:20.000Z" id="w3c-editor-s-draft-13-june-2014"><abbr title="World Wide Web Consortium">W3C</abbr> Editor's Draft <time class="dt-published" datetime="2014-06-13">13 June 2014</time></h2>
+  <h2 property="dcterms:issued" datatype="xsd:dateTime" content="2014-06-14T02:52:59.000Z" id="w3c-editor-s-draft-13-june-2014"><abbr title="World Wide Web Consortium">W3C</abbr> Editor's Draft <time class="dt-published" datetime="2014-06-13">13 June 2014</time></h2>
   <dl>
     
       <dt>This version:</dt>
@@ -1316,7 +1316,15 @@
         </dd><dt id="widl-SourceBuffer-trackDefaults"><code>trackDefaults</code> of type <span class="idlAttrType"><a href="#idl-def-TrackDefaultList" class="idlType"><code>TrackDefaultList</code></a></span>,            </dt><dd>
           <p>Specifies the default values to use if kind and/or language information is not available in the
             <a href="#init-segment">initialization segment</a> when the <a href="#sourcebuffer-init-segment-received">initialization segment received algorithm</a> needs
-            to create track objects.</p>
+            to create track objects. This attribute is initially set to an empty <a href="#idl-def-TrackDefaultList" class="idlType"><code>TrackDefaultList</code></a> object.</p>
+          <p>On getting, Return the initial value or the last value that was successfully set.</p>
+          <p>On setting, run the following steps:</p>
+          <ol>
+            <li>If this object has been removed from the <code><a href="#widl-MediaSource-sourceBuffers">sourceBuffers</a></code> attribute of the <a href="#parent-media-source">parent media source</a>, then throw an
+              <code><a href="http://dom.spec.whatwg.org/#dom-domexception-invalid_state_err">INVALID_STATE_ERR</a></code> exception and abort these steps.</li>
+            <li>If the <code><a href="#widl-SourceBuffer-updating">updating</a></code> attribute equals true, then throw an <code><a href="http://dom.spec.whatwg.org/#dom-domexception-invalid_state_err">INVALID_STATE_ERR</a></code> exception and abort these steps.</li>
+            <li>Update the attribute to the new value.</li>
+          </ol>
         </dd><dt id="widl-SourceBuffer-updating"><code>updating</code> of type <span class="idlAttrType">boolean</span>, readonly   </dt><dd>
           <p>Indicates whether the asynchronous continuation of an <code><a href="#widl-SourceBuffer-appendBuffer-void-ArrayBufferView-data">appendBuffer()</a></code>, <code><a href="#widl-SourceBuffer-appendStream-void-Stream-stream-unsigned-long-long-maxSize">appendStream()</a></code>, or <code><a href="#widl-SourceBuffer-remove-void-double-start-unrestricted-double-end">remove()</a></code>
             operation is still being processed. This attribute is initially set to false when the object is created.</p>
@@ -2817,6 +2825,7 @@
                 <li>Bug 25999 - Change appendWindowStart assignments to reference presentation start time.</li>
                 <li>Bug 26000 - Make it explicit that SourceBuffer.remove() throws an exception if duration equals NaN.</li>
                 <li>Bug 25846 - Update end of stream algorithm to invoke the append error algorithm on decode errors.</li>
+                <li>Bug 25850 - Specify SourceBuffer.trackDefaults initial value and setter/getter behavior.</li>
               </ul>
             </td>
           </tr>