[EME] Bug 25506 - Minor formatting changes.
authorDavid Dorwin <ddorwin@google.com>
Fri, 10 Oct 2014 14:55:07 -0700
changeset 463 b9d98c143ac0
parent 462 23e27105939a
child 464 1130aeb43e71
[EME] Bug 25506 - Minor formatting changes.
encrypted-media/encrypted-media-respec.html
encrypted-media/encrypted-media.html
--- a/encrypted-media/encrypted-media-respec.html	Fri Oct 10 14:54:57 2014 -0700
+++ b/encrypted-media/encrypted-media-respec.html	Fri Oct 10 14:55:07 2014 -0700
@@ -381,19 +381,19 @@
       <dt>static IsTypeSupportedResult isTypeSupported(DOMstring keySystem, optional DOMString initDataType, optional DOMString contentType, optional DOMString capability)</dt>
       <dd>
     <p>Returns whether <var title="true">keySystem</var> is supported with the <var title="true">initDataType</var>, container and codec(s) specified by <var title="true">contentType</var>, and <var title="true">capability</var>.</p>
-    <div class="example">
-      <p>The following list shows some examples.</p>
+    <p>The following list shows some examples.</p>
+    <ul>
       <dl>
         <dt>Returns whether the Some System <a def-id="keysystem"></a> may be supported. Specific containers and codecs may or may not be supported with Some System.</dt>
-        <dd><pre class="code">MediaKeys.isTypeSupported("com.example.somesystem")</pre></dd>
+        <dd><div class="example">MediaKeys.isTypeSupported("com.example.somesystem")</div</dd>
         <dt>Returns whether the Some System <a def-id="keysystem"></a> may be supported and is capable of parsing the <a def-id="initialization-data-type"></a> format "keyids". Specific containers and codecs may or may not be supported with Some System.</dt>
-        <dd><pre class="code">MediaKeys.isTypeSupported("com.example.somesystem", "keyids")</pre></dd>
+        <dd><div class="example">MediaKeys.isTypeSupported("com.example.somesystem", "keyids")</div></dd>
         <dt>Returns whether the Some System <a def-id="keysystem"></a> may be supported and is capable of parsing the <a def-id="initialization-data-type"></a> format <var title="true">initDataType</var>, the user agent is capable of demuxing the container specified by <var title="true">mimeType</var>, and the codec(s) specified by <var title="true">mimeType</var> are supported, all as specified by capability "foo".</dt>
-        <dd><pre class="code">MediaKeys.isTypeSupported("com.example.somesystem", <var title="true">initDataType</var>, <var title="true">mimeType</var>, "foo")</pre></dd>
+        <dd><div class="example">MediaKeys.isTypeSupported("com.example.somesystem", <var title="true">initDataType</var>, <var title="true">mimeType</var>, "foo")</div></dd>
         <dt>Returns whether the user agent <em>probably</em> supports <a href="#clear-key">Clear Key</a> using the <a def-id="initialization-data-type"></a> format <var title="true">initDataType</var> and the container and codec(s) specified by <var title="true">mimeType</var>.</dt>
-        <dd><pre class="code">"probably" == MediaKeys.isTypeSupported("org.w3.clearkey", <var title="true">initDataType</var>, <var title="true">mimeType</var>)</pre></dd>
+        <dd><div class="example">"probably" == MediaKeys.isTypeSupported("org.w3.clearkey", <var title="true">initDataType</var>, <var title="true">mimeType</var>)</div></dd>
       </dl>
-    </div>
+    </ul>
 
     <ol class="method-algorithm">
       <li><p>If <var title="true">keySystem</var> is an empty string or contains an unrecognized or unsupported <a def-id="keysystem"></a>, return <a def-id="IsTypeSupportedResult-empty"></a> and abort these steps. String comparison is case-sensitive.</p></li>
@@ -1345,7 +1345,7 @@
     <span id="simple-decryption-clear-key"></span> <!-- Legacy anchor name. -->
     <section id="clear-key">
     <h3>Clear Key</h3>
-    <p>The "org.w3.clearkey" <a def-id="keysystem"></a> uses plain-text clear (unencrypted) key(s) to decrypt the source.
+    <p>The <code>"org.w3.clearkey"</code> <a def-id="keysystem"></a> uses plain-text clear (unencrypted) key(s) to decrypt the source.
     No additional client-side content protection is required.
     This Key System is described below.
     </p>
@@ -1382,7 +1382,7 @@
       </li>
       <li><p>The <a def-id="getUsableKeyIds"></a> method always returns all key IDs that have been provided via <a def-id="update"></a>.</p></li>
       <li><p><a def-id="initialization-data"></a>: Implementations MAY support any combination of registered Initialization Data types [[EME-REGISTRY]].
-        Implementations SHOULD support the "<a href="keyids-format.html">keyids</a>" type and other types appropriate for content types supported by the user agent.
+        Implementations SHOULD support the <code><a href="keyids-format.html">"keyids"</a></code> type and other types appropriate for content types supported by the user agent.
       </p></li>
     </ul>
     </section>
--- a/encrypted-media/encrypted-media.html	Fri Oct 10 14:54:57 2014 -0700
+++ b/encrypted-media/encrypted-media.html	Fri Oct 10 14:55:07 2014 -0700
@@ -445,7 +445,7 @@
   </p>
   <h1 class="title p-name" id="title" property="dcterms:title">Encrypted Media Extensions</h1>
   
-  <h2 property="dcterms:issued" datatype="xsd:dateTime" content="2014-10-10T21:35:00.000Z" id="w3c-editor-s-draft-10-october-2014"><abbr title="World Wide Web Consortium">W3C</abbr> Editor's Draft <time class="dt-published" datetime="2014-10-10">10 October 2014</time></h2>
+  <h2 property="dcterms:issued" datatype="xsd:dateTime" content="2014-10-10T21:52:32.000Z" id="w3c-editor-s-draft-10-october-2014"><abbr title="World Wide Web Consortium">W3C</abbr> Editor's Draft <time class="dt-published" datetime="2014-10-10">10 October 2014</time></h2>
   <dl>
     
       <dt>This version:</dt>
@@ -621,20 +621,20 @@
       <dd>
     <p>The Content Decryption Module (CDM) is a generic term for the client component that provides the functionality, including decryption, for one or more <a href="#key-system">Key Systems</a>.</p>
     <div class="note"><div class="note-title" aria-level="2" role="heading" id="h_note_1"><span>Note</span></div><p class="">Implementations may or may not separate the implementations of CDMs or treat them as separate from the user agent.
-    This is transparent to the API and application.
-    A user agent may support one or more CDMs.</p></div>
+    This is transparent to the API and application.</p></div>
+    <p>A user agent <em class="rfc2119" title="MAY">MAY</em> support one or more CDMs.</p>
       </dd>
 
       <dt id="key-system">Key System</dt>
       <dd>
     <p>A Key System is a generic term for a decryption mechanism and/or content protection provider.
     Key System strings provide unique identification of a Key System.
-    They are used by the user agent to select the <a href="#cdm">Content Decryption Modules</a> and identify the source of a key-related event.
-    The <a href="#common-key-systems">Common Key Systems</a> are supported by all user agents. User agents may also provide additional CDMs with corresponding Key System strings.
+    They are used by the user agent to select a <a href="#cdm">CDM</a> and identify the source of a key-related event.
+    The <a href="#common-key-systems">Common Key Systems</a> are supported by all user agents. User agents <em class="rfc2119" title="MAY">MAY</em> also provide additional CDMs with corresponding Key System strings.
     </p>
 
     <p>A Key System string is always a reverse domain name.
-    Key System strings are compared using case-sensitive matching. It is recommended that CDMs use simple lower-case ASCII key system strings.</p>
+    Key System strings are compared using case-sensitive matching. It is <em class="rfc2119" title="RECOMMENDED">RECOMMENDED</em> that CDMs use simple lower-case ASCII key system strings.</p>
     <div class="note"><div class="note-title" aria-level="2" role="heading" id="h_note_2"><span>Note</span></div><p class="">For example, "com.example.somesystem".</p></div>
 
     <div class="note"><div class="note-title" aria-level="2" role="heading" id="h_note_3"><span>Note</span></div><p class="">
@@ -646,12 +646,12 @@
 
       <dt id="key-session">Key Session</dt>
       <dd>
-    <p>A Key Session, or simply Session, provides a context for message exchange with the CDM as a result of which key(s) are made available to be <a href="#cdm">CDM</a>.
+    <p>A Key Session, or simply Session, provides a context for message exchange with the CDM as a result of which key(s) are made available to the <a href="#cdm">CDM</a>.
     Sessions are embodied as <code><a href="#idl-def-MediaKeySession">MediaKeySession</a></code> objects.
     Each Key session is associated with a single instance of <a href="#initialization-data">Initialization Data</a> provided in the <code><a href="#widl-MediaKeySession-generateRequest-Promise-void--DOMString-initDataType-ArrayBuffer-ArrayBufferView-initData">generateRequest()</a></code> call.
     </p>
-    <p>Each Key Session is associated with a single <code><a href="#idl-def-MediaKeys">MediaKeys</a></code> object, and only <a href="#htmlmediaelement-extensions">media element(s)</a> associated with that object may access key(s) associated with the session.
-    Other <code><a href="#idl-def-MediaKeys">MediaKeys</a></code> objects, <a href="#cdm">CDM</a> instances, and media elements may <em>not</em> access the key session or use its key(s).
+    <p>Each Key Session is associated with a single <code><a href="#idl-def-MediaKeys">MediaKeys</a></code> object, and only media element(s) associated with that object may access key(s) associated with the session.
+    Other <code><a href="#idl-def-MediaKeys">MediaKeys</a></code> objects, <a href="#cdm">CDM</a> instances, and media elements <em class="rfc2119" title="MUST NOT">MUST NOT</em> access the key session or use its key(s).
     Key sessions and the keys they contain are no longer usable by the CDM for decryption when the <a href="#algorithms-session-close">session is closed</a>, including when the <code><a href="#idl-def-MediaKeySession">MediaKeySession</a></code> object is destroyed.
     </p>
       </dd>
@@ -662,8 +662,8 @@
 
     <p>A new Session ID is generated each time the user agent and CDM successfully create a new session.</p>
 
-    <p>Each Session ID shall be unique within the browsing context in which it was created.
-      Session IDs for <code><a href="#idl-def-SessionType.persistent">"persistent"</a></code> sessions must be unique within the <a href="http://www.w3.org/TR/html5/browsers.html#origin-0">origin</a> over time, including across browsing sessions.
+    <p>Each Session ID <em class="rfc2119" title="SHALL">SHALL</em> be unique within the browsing context in which it was created.
+      Session IDs for <code><a href="#idl-def-SessionType.persistent">"persistent"</a></code> sessions <em class="rfc2119" title="MUST">MUST</em> be unique within the <a href="http://www.w3.org/TR/html5/browsers.html#origin-0">origin</a> over time, including across browsing sessions.
     </p>
 
     <div class="note"><div class="note-title" aria-level="2" role="heading" id="h_note_4"><span>Note</span></div><p class="">The underlying content protection protocol does not necessarily need to support Session IDs.</p></div>
@@ -674,7 +674,7 @@
     <p>Unless otherwise stated, key refers to a decryption key that can be used to decrypt blocks within <a href="http://www.w3.org/TR/html5/embedded-content-0.html#media-data">media data</a>.
     Each such key is uniquely identified by a <a href="#decryption-key-id">key ID</a>.
     A key is associated with the <a href="#key-session">session</a> used to provide it to the CDM. (The same key may be present in multiple sessions.)
-    Such keys may only be provided to the <a href="#cdm">CDM</a> via an <code><a href="#widl-MediaKeySession-update-Promise-void--ArrayBuffer-ArrayBufferView-response">update()</a></code> call. (They may later be loaded by <code><a href="#widl-MediaKeySession-load-Promise-boolean--DOMString-sessionId">load()</a></code> as part of the stored session data.)
+    Such keys <em class="rfc2119" title="MUST">MUST</em> only be provided to the <a href="#cdm">CDM</a> via an <code><a href="#widl-MediaKeySession-update-Promise-void--ArrayBuffer-ArrayBufferView-response">update()</a></code> call. (They may later be loaded by <code><a href="#widl-MediaKeySession-load-Promise-boolean--DOMString-sessionId">load()</a></code> as part of the stored session data.)
     </p>
     
     <p>A key is considered <em>usable</em> if the CDM is certain the key is currently usable for decryption.</p>
@@ -685,7 +685,7 @@
       <dd>
     <p>A <a href="#decryption-key">key</a> is associated with a key ID, which uniquely identifies a key.
     The container specifies the ID of the key that can decrypt a block or set of blocks within the <a href="http://www.w3.org/TR/html5/embedded-content-0.html#media-data">media data</a>.
-    <a href="#initialization-data">Initialization Data</a> may contain key ID(s) to identify the keys that are needed to decrypt the media data.
+    <a href="#initialization-data">Initialization Data</a> <em class="rfc2119" title="MAY">MAY</em> contain key ID(s) to identify the keys that are needed to decrypt the media data.
     However, there is no requirement that Initialization Data contain any or all key IDs used in the <a href="http://www.w3.org/TR/html5/embedded-content-0.html#media-data">media data</a> or <a href="http://www.w3.org/TR/html5/embedded-content-0.html#media-resource">media resource</a>.
     <a href="#license">Licenses</a> provided to the CDM associate each key with a key ID so the <a href="#cdm">CDM</a> can select the appropriate key when decrypting an encrypted block of media data.
     </p>
@@ -702,19 +702,19 @@
     <a href="#key-system">Key Systems</a> usually require a block of initialization data containing information about the stream to be decrypted before they can construct a license request message.
     This block could be a simple key or content ID or a more complex structure containing such information.
     It should always allow unique identification of the key(s) needed to decrypt the content.
-    This initialization information may be obtained in some application-specific way or provided with the <a href="http://www.w3.org/TR/html5/embedded-content-0.html#media-data">media data</a>.
+    This initialization information <em class="rfc2119" title="MAY">MAY</em> be obtained in some application-specific way or provided with the <a href="http://www.w3.org/TR/html5/embedded-content-0.html#media-data">media data</a>.
     </p></div>
 
     <p>
-    Initialization Data is a generic term for container-specific data that is used by <a href="#cdm">CDMs</a> to generate a license request.
+    Initialization Data is a generic term for container-specific data that is used by a <a href="#cdm">CDM</a> to generate a license request.
     Initialization data found with the <a href="http://www.w3.org/TR/html5/embedded-content-0.html#media-data">media data</a> is provided to the application in the <code><a href="#widl-MediaEncryptedEventInit-initData">initData</a></code> attribute of the <code><a href="#dom-evt-encrypted">encrypted</a></code> event.
     </p>
 
     <p>
-    The format of the initialization data depends upon the type of container, and containers may support more than one format
+    The format of the initialization data depends upon the type of container, and containers <em class="rfc2119" title="MAY">MAY</em> support more than one format
     of initialization data. The <dfn id="initialization-data-type">initialization data type</dfn> is a string that indicates what
     format the initialization data is provided in. Initialization data type strings are always matched case-sensitively. It is
-    recommended that initialization data type strings are lower-case ASCII strings.
+    <em class="rfc2119" title="RECOMMENDED">RECOMMENDED</em> that initialization data type strings are lower-case ASCII strings.
     </p>
 
     <p>
@@ -726,16 +726,16 @@
       <dt id="cross-origin">Cross Origin Limitations</dt>
       <dd>
     <p>During playback, embedded media data is exposed to script in the embedding <a href="http://www.w3.org/TR/html5/browsers.html#origin-0">origin</a>.
-    In order for the API to provide <a href="#initialization-data">Initialization Data</a> in the <code><a href="#dom-evt-encrypted">encrypted</a></code> event, <a href="http://www.w3.org/TR/html5/embedded-content-0.html#media-data">media data</a> must be <a href="http://www.w3.org/TR/html5/infrastructure.html#cors-same-origin">CORS-same-origin</a> with the embedding page.
-    If <a href="http://www.w3.org/TR/html5/embedded-content-0.html#media-data">media data</a> is cross-origin with the embedding document, authors should use the <code><a href="http://www.w3.org/TR/html5/embedded-content-0.html#attr-media-crossorigin">crossorigin</a></code> attribute
-    on the <a href="#htmlmediaelement-extensions">media element</a> and CORS headers on the <a href="http://www.w3.org/TR/html5/embedded-content-0.html#media-data">media data</a> response to make it <a href="http://www.w3.org/TR/html5/infrastructure.html#cors-same-origin">CORS-same-origin</a>.
+    In order for the API to provide <a href="#initialization-data">Initialization Data</a> in the <code><a href="#dom-evt-encrypted">encrypted</a></code> event, <a href="http://www.w3.org/TR/html5/embedded-content-0.html#media-data">media data</a> <em class="rfc2119" title="MUST">MUST</em> be <a href="http://www.w3.org/TR/html5/infrastructure.html#cors-same-origin">CORS-same-origin</a> with the embedding page.
+    If <a href="http://www.w3.org/TR/html5/embedded-content-0.html#media-data">media data</a> is cross-origin with the embedding document, authors <em class="rfc2119" title="SHOULD">SHOULD</em> use the <code><a href="http://www.w3.org/TR/html5/embedded-content-0.html#attr-media-crossorigin">crossorigin</a></code> attribute
+    on the <code><a href="http://www.w3.org/TR/html5/embedded-content-0.html#htmlmediaelement">HTMLMediaElement</a></code> and CORS headers on the <a href="http://www.w3.org/TR/html5/embedded-content-0.html#media-data">media data</a> response to make it <a href="http://www.w3.org/TR/html5/infrastructure.html#cors-same-origin">CORS-same-origin</a>.
     </p>
       </dd>
 
       <dt id="mixed-content">Mixed Content Limitations</dt>
       <dd>
     <p>During playback, embedded media data is exposed to script in the embedding <a href="http://www.w3.org/TR/html5/browsers.html#origin-0">origin</a>.
-    In order for the API to provide <a href="#initialization-data">Initialization Data</a> in the <code><a href="#dom-evt-encrypted">encrypted</a></code> event, <a href="http://www.w3.org/TR/html5/embedded-content-0.html#media-data">media data</a> must not be Mixed Content [<cite><a class="bibref" href="#bib-MIXED-CONTENT">MIXED-CONTENT</a></cite>].
+    In order for the API to provide <a href="#initialization-data">Initialization Data</a> in the <code><a href="#dom-evt-encrypted">encrypted</a></code> event, <a href="http://www.w3.org/TR/html5/embedded-content-0.html#media-data">media data</a> <em class="rfc2119" title="MUST NOT">MUST NOT</em> be Mixed Content [<cite><a class="bibref" href="#bib-MIXED-CONTENT">MIXED-CONTENT</a></cite>].
     </p>
       </dd>
     </dl>
@@ -788,13 +788,13 @@
 
     
       <table class="parameters"><tbody><tr><th>Parameter</th><th>Type</th><th>Nullable</th><th>Optional</th><th>Description</th></tr><tr><td class="prmName">keySystem</td><td class="prmType"><code>DOMString</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc"></td></tr></tbody></table><div><em>Return type: </em><code>Promise&lt;<a href="#idl-def-MediaKeys" class="idlType"><code>MediaKeys</code></a>&gt;</code></div><p>When this method is invoked, the user agent must run the following steps:</p><ol class="method-algorithm">
-      <li><p>If <var title="true">keySystem</var> is an empty string, return a promise rejected with a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is <code><a href="#dfn-InvalidAccessError">"InvalidAccessError"</a></code>.</p></li>
-      <li><p>If <var title="true">keySystem</var> is not one of the <a href="#key-system">Key Systems</a> supported by the user agent, return a promise rejected with a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is <code><a href="#dfn-NotSupportedError">"NotSupportedError"</a></code>. String comparison is case-sensitive.</p></li>
-      <li><p>If <var title="true">keySystem</var> is not supported or not allowed in the <a href="http://www.w3.org/TR/html5/browsers.html#origin-0">origin</a> of the calling context's <a href="http://dom.spec.whatwg.org/#concept-document">Document</a>, return a promise rejected with a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is <code><a href="#dfn-NotSupportedError">"NotSupportedError"</a></code>.</p></li>
+      <li><p>If <var title="true">keySystem</var> is an empty string, return a promise rejected with a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is <code><a href="#dfn-InvalidAccessError">InvalidAccessError</a></code>.</p></li>
+      <li><p>If <var title="true">keySystem</var> is not one of the <a href="#key-system">Key Systems</a> supported by the user agent, return a promise rejected with a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is <code><a href="#dfn-NotSupportedError">NotSupportedError</a></code>. String comparison is case-sensitive.</p></li>
+      <li><p>If <var title="true">keySystem</var> is not supported or not allowed in the <a href="http://www.w3.org/TR/html5/browsers.html#origin-0">origin</a> of the calling context's <a href="http://dom.spec.whatwg.org/#concept-document">Document</a>, return a promise rejected with a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is <code><a href="#dfn-NotSupportedError">NotSupportedError</a></code>.</p></li>
       <li><p>Let <var>promise</var> be a new promise.</p></li>
       <li><p>Run the following steps asynchronously:</p>
         <ol>
-          <li><p>Let <var title="true">cdm</var> be the <a href="#cdm">content decryption module</a> corresponding to <var title="true">keySystem</var>.</p></li>
+          <li><p>Let <var title="true">cdm</var> be the <a href="#cdm">CDM</a> corresponding to <var title="true">keySystem</var>.</p></li>
           <li><p>Load and initialize the <var title="true">cdm</var> if necessary.</p></li>
           <li><p>If <var title="true">cdm</var> fails to load or initialize, reject <var>promise</var> with a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is the appropriate <a href="#error-names">error name</a>.</p></li>
 
@@ -814,8 +814,8 @@
 
     
       <table class="parameters"><tbody><tr><th>Parameter</th><th>Type</th><th>Nullable</th><th>Optional</th><th>Description</th></tr><tr><td class="prmName">sessionType</td><td class="prmType"><code><a href="#idl-def-SessionType" class="idlType"><code>SessionType</code></a> = "temporary"</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptTrue"><span role="img" aria-label="True">✔</span></td><td class="prmDesc"></td></tr></tbody></table><div><em>Return type: </em><code><a href="#idl-def-MediaKeySession" class="idlType"><code>MediaKeySession</code></a></code></div><p>When this method is invoked, the user agent must run the following steps:</p><ol class="method-algorithm">
-      <!-- TODO: Reference the CDM loaded during initialization instead of "<a href="#cdm">content decryption module</a> corresponding to the <a def-id="keySystem-attribute"></a> attribute". Here and elsewhere. -->
-      <li><p>If <var title="true">sessionType</var> is not supported by the <a href="#cdm">content decryption module</a> corresponding to the <code><a href="#widl-MediaKeys-keySystem">keySystem</a></code> attribute, throw a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is <code><a href="#dfn-NotSupportedError">"NotSupportedError"</a></code>.</p></li>
+      <!-- TODO: Reference the CDM loaded during initialization instead of "<a def-id="cdm"></a> corresponding to the <a def-id="keySystem-attribute"></a> attribute". Here and elsewhere. -->
+      <li><p>If <var title="true">sessionType</var> is not supported by the <a href="#cdm">CDM</a> corresponding to the <code><a href="#widl-MediaKeys-keySystem">keySystem</a></code> attribute, throw a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is <code><a href="#dfn-NotSupportedError">NotSupportedError</a></code>.</p></li>
       <li><p>Let <var title="true">session</var> be a new <code><a href="#idl-def-MediaKeySession">MediaKeySession</a></code> object, and initialize it as follows:</p>
         <ol>
           <li><p>Let the <code><a href="#widl-MediaKeySession-sessionId">sessionId</a></code> attribute be the empty string.</p></li>
@@ -828,20 +828,20 @@
       </li>
       <li><p>Return <var title="true">session</var>.</p></li>
     </ol></dd><dt id="widl-MediaKeys-isTypeSupported-IsTypeSupportedResult-DOMstring-keySystem-DOMString-initDataType-DOMString-contentType-DOMString-capability"><code>isTypeSupported</code>, static</dt><dd>
-    <p>Returns whether <var title="true">keySystem</var> is supported with the <var title="true"><a href="#initialization-data-type">initDataType</a></var>, container and codec(s) specified by <var title="true">contentType</var>, and <var title="true">capability</var>.</p>
-    <div class="example">
-      <p>The following list shows some examples.</p>
+    <p>Returns whether <var title="true">keySystem</var> is supported with the <var title="true">initDataType</var>, container and codec(s) specified by <var title="true">contentType</var>, and <var title="true">capability</var>.</p>
+    <p>The following list shows some examples.</p>
+    <ul>
       <dl>
         <dt>Returns whether the Some System <a href="#key-system">Key System</a> may be supported. Specific containers and codecs may or may not be supported with Some System.</dt>
-        <dd><pre class="code">MediaKeys.isTypeSupported("com.example.somesystem")</pre></dd>
-        <dt>Returns whether the Some System <a href="#key-system">Key System</a> may be supported and is capable of parsing the <a href="#initialization-data-type">initialization data type</a> format "keyids". Specific containers and codecs may or may not be supported with Some System.</dt>
-        <dd><pre class="code">MediaKeys.isTypeSupported("com.example.somesystem", "keyids")</pre></dd>
-        <dt>Returns whether the Some System <a href="#key-system">Key System</a> may be supported and is capable of parsing the <a href="#initialization-data-type">initialization data type</a> format <var title="true">initDataType</var>, the user agent is capable of demuxing the container specified by <var title="true">mimeType</var>, and the codec(s) specified by <var title="true">mimeType</var> are supported, all as specified by capability "foo".</dt>
-        <dd><pre class="code">MediaKeys.isTypeSupported("com.example.somesystem", <var title="true">initDataType</var>, <var title="true">mimeType</var>, "foo")</pre></dd>
-        <dt>Returns whether the user agent <em>probably</em> supports <a href="#clear-key">Clear Key</a> using the <a href="#initialization-data-type">initialization data type</a> format <var title="true">initDataType</var> and the container and codec(s) specified by <var title="true">mimeType</var>.</dt>
-        <dd><pre class="code">"probably" == MediaKeys.isTypeSupported("org.w3.clearkey", <var title="true">initDataType</var>, <var title="true">mimeType</var>)</pre></dd>
+        <dd><div class="example">MediaKeys.isTypeSupported("com.example.somesystem")
+        </div></dd><dt>Returns whether the Some System <a href="#key-system">Key System</a> may be supported and is capable of parsing the <a href="#initialization-data">Initialization Data</a> format "keyids". Specific containers and codecs may or may not be supported with Some System.</dt>
+        <dd><div class="example">MediaKeys.isTypeSupported("com.example.somesystem", "keyids")</div></dd>
+        <dt>Returns whether the Some System <a href="#key-system">Key System</a> may be supported and is capable of parsing the <a href="#initialization-data">Initialization Data</a> format <var title="true">initDataType</var>, the user agent is capable of demuxing the container specified by <var title="true">mimeType</var>, and the codec(s) specified by <var title="true">mimeType</var> are supported, all as specified by capability "foo".</dt>
+        <dd><div class="example">MediaKeys.isTypeSupported("com.example.somesystem", <var title="true">initDataType</var>, <var title="true">mimeType</var>, "foo")</div></dd>
+        <dt>Returns whether the user agent <em>probably</em> supports <a href="#clear-key">Clear Key</a> using the <a href="#initialization-data">Initialization Data</a> format <var title="true">initDataType</var> and the container and codec(s) specified by <var title="true">mimeType</var>.</dt>
+        <dd><div class="example">"probably" == MediaKeys.isTypeSupported("org.w3.clearkey", <var title="true">initDataType</var>, <var title="true">mimeType</var>)</div></dd>
       </dl>
-    </div>
+    </ul>
 
     
       <table class="parameters"><tbody><tr><th>Parameter</th><th>Type</th><th>Nullable</th><th>Optional</th><th>Description</th></tr><tr><td class="prmName">keySystem</td><td class="prmType"><code>DOMstring</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc"></td></tr><tr><td class="prmName">initDataType</td><td class="prmType"><code>DOMString</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptTrue"><span role="img" aria-label="True">✔</span></td><td class="prmDesc"></td></tr><tr><td class="prmName">contentType</td><td class="prmType"><code>DOMString</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptTrue"><span role="img" aria-label="True">✔</span></td><td class="prmDesc"></td></tr><tr><td class="prmName">capability</td><td class="prmType"><code>DOMString</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptTrue"><span role="img" aria-label="True">✔</span></td><td class="prmDesc"></td></tr></tbody></table><div><em>Return type: </em><code><a href="#idl-def-IsTypeSupportedResult" class="idlType"><code>IsTypeSupportedResult</code></a></code></div><p>When this method is invoked, the user agent must run the following steps:</p><ol class="method-algorithm">
@@ -866,8 +866,8 @@
         </dl>
       </li>
 
-      <li><p>If <var title="true">initDataType</var> is an empty string or contains an unrecognized or unsupported <a href="#initialization-data-type">initialization data type</a>, return <code><a href="#idl-def-IsTypeSupportedResult.empty-string">""</a></code> and abort these steps. String comparison is case-sensitive.</p></li>
-      <li><p>If <var title="true">initDataType</var> is not an <a href="#initialization-data-type">initialization data type</a> supported by the <var title="true">keySystem</var> implementation, return <code><a href="#idl-def-IsTypeSupportedResult.empty-string">""</a></code> and abort these steps.</p></li>
+      <li><p>If <var title="true">initDataType</var> is an empty string or contains an unrecognized or unsupported <a href="#initialization-data">Initialization Data</a>, return <code><a href="#idl-def-IsTypeSupportedResult.empty-string">""</a></code> and abort these steps. String comparison is case-sensitive.</p></li>
+      <li><p>If <var title="true">initDataType</var> is not an <a href="#initialization-data">Initialization Data</a> supported by the <var title="true">keySystem</var> implementation, return <code><a href="#idl-def-IsTypeSupportedResult.empty-string">""</a></code> and abort these steps.</p></li>
       <li><p>If the <var title="true">keySystem</var> implementation supporting <var title="true">initDataType</var> is not available and usable, return <code><a href="#idl-def-IsTypeSupportedResult.empty-string">""</a></code> and abort these steps.</p></li>
       <li><p>If <var title="true">contentType</var> was not provided, follow the steps for the first matching condition from the following list and abort these steps:</p>
         <dl class="switch">
@@ -881,8 +881,8 @@
       <li><p>If <var title="true">contentType</var> is an empty string or contains an invalid or unrecognized MIME type, return <code><a href="#idl-def-IsTypeSupportedResult.empty-string">""</a></code> and abort these steps.</p></li>
       <li><p>Let <var title="true">container</var> be the container type specified by <var title="true">contentType</var>.</p></li>
       <li><p>Let <var title="true">parameters</var> be the RFC 6381 [<cite><a class="bibref" href="#bib-RFC6381">RFC6381</a></cite>] parameters, if any, specified by <var title="true">contentType</var>.</p></li>
-      <li><p>Let <var title="true">media types</var> be the set of media types specified by <var title="true">parameters</var>. It may be empty. The case-sensitivity of string comparisons is determined by the appropriate RFC or other specification.</p>
-        <div class="note"><div class="note-title" aria-level="2" role="heading" id="h_note_8"><span>Note</span></div><p class="">For example, all of the codecs. Case-sensitive string comparison is recommended because RFC 6381 [<cite><a class="bibref" href="#bib-RFC6381">RFC6381</a></cite>] says, "Values are case sensitive" for some formats.</p></div>
+      <li><p>Let <var title="true">media types</var> be the set of media types specified by <var title="true">parameters</var>. It <em class="rfc2119" title="MAY">MAY</em> be empty. The case-sensitivity of string comparisons is determined by the appropriate RFC or other specification.</p>
+        <div class="note"><div class="note-title" aria-level="2" role="heading" id="h_note_8"><span>Note</span></div><p class="">For example, all of the codecs. Case-sensitive string comparison is <em class="rfc2119" title="RECOMMENDED">RECOMMENDED</em> because RFC 6381 [<cite><a class="bibref" href="#bib-RFC6381">RFC6381</a></cite>] says, "Values are case sensitive" for some formats.</p></div>
       </li>
       <li><p>If the user agent does not support <var title="true">container</var>, return <code><a href="#idl-def-IsTypeSupportedResult.empty-string">""</a></code> and abort these steps. The case-sensitivity of string comparisons is determined by the appropriate RFC.</p>
         <div class="note"><div class="note-title" aria-level="2" role="heading" id="h_note_9"><span>Note</span></div><p class="">Per RFC 6838 [<cite><a class="bibref" href="#bib-RFC6838">RFC6838</a></cite>], "Both top-level type and subtype names are case-insensitive."</p></div>
@@ -918,8 +918,8 @@
 
     
       <table class="parameters"><tbody><tr><th>Parameter</th><th>Type</th><th>Nullable</th><th>Optional</th><th>Description</th></tr><tr><td class="prmName">serverCertificate</td><td class="prmType"><code>(ArrayBuffer or ArrayBufferView)</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc"></td></tr></tbody></table><div><em>Return type: </em><code>Promise&lt;void&gt;</code></div><p>When this method is invoked, the user agent must run the following steps:</p><ol class="method-algorithm">
-      <li><p>If <var title="true">serverCertificate</var> is an empty array, return a promise rejected with a new a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is <code><a href="#dfn-InvalidAccessError">"InvalidAccessError"</a></code>.</p></li>
-      <li><p>If the <a href="#cdm">content decryption module</a> corresponding to the <code><a href="#widl-MediaKeys-keySystem">keySystem</a></code> attribute does not support server certificates, return a promise rejected with a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is <code><a href="#dfn-NotSupportedError">"NotSupportedError"</a></code>.</p></li>
+      <li><p>If <var title="true">serverCertificate</var> is an empty array, return a promise rejected with a new a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is <code><a href="#dfn-InvalidAccessError">InvalidAccessError</a></code>.</p></li>
+      <li><p>If the <a href="#cdm">CDM</a> corresponding to the <code><a href="#widl-MediaKeys-keySystem">keySystem</a></code> attribute does not support server certificates, return a promise rejected with a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is <code><a href="#dfn-NotSupportedError">NotSupportedError</a></code>.</p></li>
       <li><p>Let <var>certificate</var> be a copy of the contents of the <var title="true">serverCertificate</var> parameter.</p></li>
       <li><p>Let <var>promise</var> be a new promise.</p></li>
       <li><p>Run the following steps asynchronously:</p>
@@ -954,20 +954,20 @@
 <span class="idlMethod">    <span class="idlMethType">Promise&lt;void&gt;</span>                  <span class="idlMethName"><a href="#widl-MediaKeySession-remove-Promise-void">remove</a></span> ();</span>
 <span class="idlMethod">    <span class="idlMethType">Promise&lt;sequence&lt;ArrayBuffer&gt;&gt;</span> <span class="idlMethName"><a href="#widl-MediaKeySession-getUsableKeyIds-Promise-sequence-ArrayBuffer">getUsableKeyIds</a></span> ();</span>
 };</span></pre><section id="attributes-1"><h3 role="heading" id="h3_attributes-1"><span class="secno">3.1 </span>Attributes</h3><dl class="attributes"><dt id="widl-MediaKeySession-closed"><code>closed</code> of type <span class="idlAttrType">Promise&lt;void&gt;</span>, readonly   </dt><dd>
-        <p>Signals when object becomes closed as a result of the <a href="#algorithms-session-close">Session Close</a> algorithm being run.
+        <p>Signals when object becomes closed as a result of the <a href="#algorithms-session-close">session close algorithm</a> being run.
         This promise can only be fulfilled and is never rejected.</p>
       </dd><dt id="widl-MediaKeySession-expiration"><code>expiration</code> of type <span class="idlAttrType">unrestricted double</span>, readonly   </dt><dd>
         <p>The time, in milliseconds since 01 January, 1970 UTC, after which the key(s) in the session will no longer be usable to decrypt <a href="http://www.w3.org/TR/html5/embedded-content-0.html#media-data">media data</a>, or <code>NaN</code> if no such time exists, as determined by the CDM.</p>
       </dd><dt id="widl-MediaKeySession-sessionId"><code>sessionId</code> of type <span class="idlAttrType">DOMString</span>, readonly   </dt><dd>
-        <p>The <a href="#session-id">Session ID</a> for this object and the associated key(s) or license(s).</p>
+        <p>The <a href="#session-id">Session Id</a> for this object and the associated key(s) or license(s).</p>
       </dd></dl></section><section id="methods-1"><h3 role="heading" id="h3_methods-1"><span class="secno">3.2 </span>Methods</h3><dl class="methods"><dt id="widl-MediaKeySession-close-Promise-void"><code>close</code></dt><dd>
     <p>Indicates that the application no longer needs the session and the CDM should release any resources associated with this object and close it.</p>
     <div class="note"><div class="note-title" aria-level="2" role="heading" id="h_note_12"><span>Note</span></div><p class="">The returned promise is resolved when the request has been processed, and the <code><a href="#widl-MediaKeySession-closed">closed</a></code> attribute promise is resolved when the session is closed.</p></div>
 
     
       <div><em>No parameters.</em></div><div><em>Return type: </em><code>Promise&lt;void&gt;</code></div><p>When this method is invoked, the user agent must run the following steps:</p><ol class="method-algorithm">
-      <li><p>If this object's <var title="true">callable</var> value is false, return a promise rejected with a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is <code><a href="#dfn-InvalidStateError">"InvalidStateError"</a></code>.</p></li>
-      <li><p>If the <a href="#algorithms-session-close">Session Close</a> algorithm has been run on this object, return a resolved promise.</p></li>
+      <li><p>If this object's <var title="true">callable</var> value is false, return a promise rejected with a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is <code><a href="#dfn-InvalidStateError">InvalidStateError</a></code>.</p></li>
+      <li><p>If the <a href="#algorithms-session-close">session close algorithm</a> has been run on this object, return a resolved promise.</p></li>
       <li><p>Let <var>promise</var> be a new promise.</p></li>
       <li><p>Run the following steps asynchronously:</p>
         <ol>
@@ -978,7 +978,7 @@
                 <p>Process the close request.</p>
                 <p>Do not remove stored session data.</p>
               </li>
-              <li><p>If the previous step caused the session to be closed, run the <a href="#algorithms-session-close">Session Close</a> algorithm on this object.</p></li>
+              <li><p>If the previous step caused the session to be closed, run the <a href="#algorithms-session-close">session close algorithm</a> on this object.</p></li>
             </ol>
           </li>
           <li><p>Resolve <var>promise</var>.</p></li>
@@ -988,23 +988,23 @@
     </ol></dd><dt id="widl-MediaKeySession-generateRequest-Promise-void--DOMString-initDataType-ArrayBuffer-ArrayBufferView-initData"><code>generateRequest</code></dt><dd>
     <p>Generates a request based on the <var title="true">initData</var>.</p>
     <p><var title="true">initData</var> is <a href="#initialization-data">Initialization Data</a>, and
-    <var title="true">initDataType</var> is an <a href="#initialization-data-type">initialization data type</a> that indicates how to interpret <var title="true">initData</var>.
+    <var title="true">initDataType</var> is an <a href="#initialization-data">Initialization Data</a> that indicates how to interpret <var title="true">initData</var>.
     </p>
 
     
       <table class="parameters"><tbody><tr><th>Parameter</th><th>Type</th><th>Nullable</th><th>Optional</th><th>Description</th></tr><tr><td class="prmName">initDataType</td><td class="prmType"><code>DOMString</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc"></td></tr><tr><td class="prmName">initData</td><td class="prmType"><code>(ArrayBuffer or ArrayBufferView)</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc"></td></tr></tbody></table><div><em>Return type: </em><code>Promise&lt;void&gt;</code></div><p>When this method is invoked, the user agent must run the following steps:</p><ol class="method-algorithm">
-      <li><p>If this object's <var title="true">uninitialized</var> value is false, return a promise rejected with a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is <code><a href="#dfn-InvalidStateError">"InvalidStateError"</a></code>.</p></li>
+      <li><p>If this object's <var title="true">uninitialized</var> value is false, return a promise rejected with a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is <code><a href="#dfn-InvalidStateError">InvalidStateError</a></code>.</p></li>
       <li><p>Let this object's <var title="true">uninitialized</var> be false.</p></li><!-- For simplicity and consistency, this object cannot be reused after any failure. -->
-      <li><p>If <var title="true">initDataType</var> is an empty string, return a promise rejected with a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is <code><a href="#dfn-InvalidAccessError">"InvalidAccessError"</a></code>.</p></li>
-      <li><p>If <var title="true">initData</var> is an empty array, return a promise rejected with a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is <code><a href="#dfn-InvalidAccessError">"InvalidAccessError"</a></code>.</p></li>
+      <li><p>If <var title="true">initDataType</var> is an empty string, return a promise rejected with a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is <code><a href="#dfn-InvalidAccessError">InvalidAccessError</a></code>.</p></li>
+      <li><p>If <var title="true">initData</var> is an empty array, return a promise rejected with a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is <code><a href="#dfn-InvalidAccessError">InvalidAccessError</a></code>.</p></li>
       <li><p>Let <var title="true">media keys</var> be the <code><a href="#idl-def-MediaKeys">MediaKeys</a></code> object that created this object.</p></li>
-      <li><p>If the <a href="#cdm">content decryption module</a> corresponding to <var title="true">media keys</var>'s <code><a href="#widl-MediaKeys-keySystem">keySystem</a></code> attribute does not support <var title="true">initDataType</var> as an <a href="#initialization-data-type">initialization data type</a>, return a promise rejected with a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is <code><a href="#dfn-NotSupportedError">"NotSupportedError"</a></code>. String comparison is case-sensitive.</p></li>
+      <li><p>If the <a href="#cdm">CDM</a> corresponding to <var title="true">media keys</var>'s <code><a href="#widl-MediaKeys-keySystem">keySystem</a></code> attribute does not support <var title="true">initDataType</var> as an <a href="#initialization-data">Initialization Data</a>, return a promise rejected with a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is <code><a href="#dfn-NotSupportedError">NotSupportedError</a></code>. String comparison is case-sensitive.</p></li>
       <li><p>Let <var>init data</var> be a copy of the contents of the <var title="true">initData</var> parameter.</p></li>
       <li><p>Let <var title="true">session type</var> be this object's <var title="true">session type</var>.</p></li>
       <li><p>Let <var>promise</var> be a new promise.</p></li>
       <li><p>Run the following steps asynchronously:</p>
         <ol>
-          <li><p>If the <var>init data</var> is not valid for <var title="true">initDataType</var>, reject <var>promise</var> with a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is <code><a href="#dfn-InvalidAccessError">"InvalidAccessError"</a></code>.</p></li>
+          <li><p>If the <var>init data</var> is not valid for <var title="true">initDataType</var>, reject <var>promise</var> with a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is <code><a href="#dfn-InvalidAccessError">InvalidAccessError</a></code>.</p></li>
           <li><p>Let <var>sanitized init data</var> be a validated and/or sanitized version of <var>init data</var>.</p>
             <div class="note"><div class="note-title" aria-level="2" role="heading" id="h_note_13"><span>Note</span></div><p class="">The user agent should thoroughly validate the Initialization Data before passing it to the CDM.
               This may include verifying values are within reasonable limits, stripping irrelevant data or fields, pre-parsing it, sanitizing it, and/or generating a fully sanitized version.
@@ -1013,13 +1013,13 @@
               For Initialization Data formats that support multiple entries, the user agent should remove entries that are not needed by the CDM.
             </p></div>
           </li>
-          <li><p>If the previous step failed, reject <var>promise</var> with a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is <code><a href="#dfn-InvalidAccessError">"InvalidAccessError"</a></code>.</p></li>
+          <li><p>If the previous step failed, reject <var>promise</var> with a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is <code><a href="#dfn-InvalidAccessError">InvalidAccessError</a></code>.</p></li>
           <li><p>Let <var title="true">session id</var> be the empty string.</p></li>
           <li><p>Let <var title="true">message</var> be null.</p></li>
           <li><p>Let <var title="true">cdm</var> be the CDM loaded during the <a href="#widl-MediaKeys-create-Promise-MediaKeys--DOMString-keySystem">initialization</a> of <var title="true">media keys</var>.</p></li>
           <li><p>Use the <var title="true">cdm</var> to execute the following steps:</p>
             <ol>
-              <li><p>If the <var>init data</var> is not supported by the <var title="true">cdm</var>, reject <var>promise</var> with a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is <code><a href="#dfn-NotSupportedError">"NotSupportedError"</a></code>.</p></li>
+              <li><p>If the <var>init data</var> is not supported by the <var title="true">cdm</var>, reject <var>promise</var> with a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is <code><a href="#dfn-NotSupportedError">NotSupportedError</a></code>.</p></li>
               <li><p>Follow the steps for the first matching condition from the following list:</p>
                 <dl class="switch">
                   <dt>If <var title="true">session type</var> is <code><a href="#idl-def-SessionType.temporary">"temporary"</a></code></dt>
@@ -1034,20 +1034,20 @@
                 <div class="note"><div class="note-title" aria-level="2" role="heading" id="h_note_16"><span>Note</span></div><p class="">The license server determines the type of license that is returned, either persistent or non-persistent. A persistent license cannot be added to a non-persistable session.</p></div>
               </li>
 
-              <li><p>Let <var title="true">session id</var> be a unique <a href="#session-id">Session ID</a> string.</p>
-                <p>If <var title="true">session type</var> is <code><a href="#idl-def-SessionType.persistent">"persistent"</a></code>, the ID must be unique within the the <a href="http://www.w3.org/TR/html5/browsers.html#origin-0">origin</a> of this object's <a href="http://dom.spec.whatwg.org/#concept-document">Document</a> over time, including across Documents and browsing sessions.</p>
+              <li><p>Let <var title="true">session id</var> be a unique <a href="#session-id">Session Id</a> string.</p>
+                <p>If <var title="true">session type</var> is <code><a href="#idl-def-SessionType.persistent">"persistent"</a></code>, the ID <em class="rfc2119" title="MUST">MUST</em> be unique within the the <a href="http://www.w3.org/TR/html5/browsers.html#origin-0">origin</a> of this object's <a href="http://dom.spec.whatwg.org/#concept-document">Document</a> over time, including across Documents and browsing sessions.</p>
               </li>
               <li><p>Let <var title="true">message</var> be a request for the <var title="true">requested session type</var> generated based on the <var>init data</var>, which is interpreted per <var title="true">initDataType</var>.</p>
                 <div class="note"><div class="note-title" aria-level="2" role="heading" id="h_note_17"><span>Note</span></div><p class="">For example, a license request.</p></div>
-                <p>The <var title="true">cdm</var> must not use any stream-specific data, including <a href="http://www.w3.org/TR/html5/embedded-content-0.html#media-data">media data</a>, not provided via the <var>init data</var>.</p>
-                <p>The <var title="true">cdm</var> should <em>not</em> store session data, including the session ID, at this point. See <a href="#session-storage">Session Storage and Persistence</a>.</p>
+                <p>The <var title="true">cdm</var> <em class="rfc2119" title="MUST NOT">MUST NOT</em> use any stream-specific data, including <a href="http://www.w3.org/TR/html5/embedded-content-0.html#media-data">media data</a>, not provided via the <var>init data</var>.</p>
+                <p>The <var title="true">cdm</var> <em class="rfc2119" title="SHOULD NOT">SHOULD NOT</em> store session data, including the session ID, at this point. See <a href="#session-storage">Session Storage and Persistence</a>.</p>
               </li>
             </ol>
           </li>
           <li><p>If any of the preceding steps failed, reject <var>promise</var> with a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is the appropriate <a href="#error-names">error name</a>.</p></li>
           <li><p>Set the <code><a href="#widl-MediaKeySession-sessionId">sessionId</a></code> attribute to <var title="true">session id</var>.</p></li>
           <li><p>Let this object's <var title="true">callable</var> be true.</p></li>
-          <li><p>Run the <a href="#algorithms-queue-message">Queue a "message" Event</a> algorithm on the <var title="true">session</var>, providing <code><a href="#idl-def-MediaKeyMessageType.licenserequest">"licenserequest"</a></code> and <var title="true">message</var>.</p></li>
+          <li><p>Run the <a href="#algorithms-queue-message">queue a "message" event algorithm</a> on the <var title="true">session</var>, providing <code><a href="#idl-def-MediaKeyMessageType.licenserequest">"licenserequest"</a></code> and <var title="true">message</var>.</p></li>
           <li><p>Resolve <var>promise</var>.</p></li>
         </ol>
       </li>
@@ -1058,14 +1058,14 @@
     
     
       <div><em>No parameters.</em></div><div><em>Return type: </em><code>Promise&lt;sequence&lt;ArrayBuffer&gt;&gt;</code></div><p>When this method is invoked, the user agent must run the following steps:</p><ol class="method-algorithm">
-      <li><p>If this object's <var title="true">callable</var> value is false, return a promise rejected with a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is <code><a href="#dfn-InvalidStateError">"InvalidStateError"</a></code>.</p></li>
+      <li><p>If this object's <var title="true">callable</var> value is false, return a promise rejected with a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is <code><a href="#dfn-InvalidStateError">InvalidStateError</a></code>.</p></li>
       <li><p>Let <var>promise</var> be a new promise.</p></li>
       <li><p>Run the following steps asynchronously:</p>
         <ol>
           <li><p>Let <var title="true">cdm</var> be the CDM loaded during the <a href="#widl-MediaKeys-create-Promise-MediaKeys--DOMString-keySystem">initialization</a> of the <code><a href="#idl-def-MediaKeys">MediaKeys</a></code> object that created this object.</p></li>
           <li><p>Use the <var title="true">cdm</var> to execute the following steps:</p>
             <ol>
-              <li><p>Let <var title="true">usable key ids</var> be a list of the key IDs for keys in the session that the CDM <em>knows</em> are currently usable to decrypt <a href="http://www.w3.org/TR/html5/embedded-content-0.html#media-data">media data</a>. <var title="true">usable key ids</var> must not contain IDs for keys that <em>may not</em> currently be usable. Each element must be unique.</p></li>
+              <li><p>Let <var title="true">usable key ids</var> be a list of the key IDs for keys in the session that the CDM <em>knows</em> are currently usable to decrypt <a href="http://www.w3.org/TR/html5/embedded-content-0.html#media-data">media data</a>. <var title="true">usable key ids</var> <em class="rfc2119" title="MUST NOT">MUST NOT</em> contain IDs for keys that <em>may not</em> currently be usable. Each element <em class="rfc2119" title="MUST">MUST</em> be unique.</p></li>
             </ol>
           </li>
           <li>
@@ -1081,12 +1081,12 @@
 
     
       <table class="parameters"><tbody><tr><th>Parameter</th><th>Type</th><th>Nullable</th><th>Optional</th><th>Description</th></tr><tr><td class="prmName">sessionId</td><td class="prmType"><code>DOMString</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc"></td></tr></tbody></table><div><em>Return type: </em><code>Promise&lt;boolean&gt;</code></div><p>When this method is invoked, the user agent must run the following steps:</p><ol class="method-algorithm">
-      <li><p>If this object's <var title="true">uninitialized</var> value is false, return a promise rejected with a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is <code><a href="#dfn-InvalidStateError">"InvalidStateError"</a></code>.</p></li>
+      <li><p>If this object's <var title="true">uninitialized</var> value is false, return a promise rejected with a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is <code><a href="#dfn-InvalidStateError">InvalidStateError</a></code>.</p></li>
       <li><p>Let this object's <var title="true">uninitialized</var> be false.</p></li><!-- For simplicity and consistency, this object cannot be reused after any failure. -->
-      <li><p>If <var title="true">sessionId</var> is an empty string, return a promise rejected with a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is <code><a href="#dfn-InvalidAccessError">"InvalidAccessError"</a></code>.</p></li>
-      <li><p>If this object's <var title="true">session type</var> is not <code><a href="#idl-def-SessionType.persistent">"persistent"</a></code>, return a promise rejected with a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is <code><a href="#dfn-InvalidAccessError">"InvalidAccessError"</a></code>.</p></li>
+      <li><p>If <var title="true">sessionId</var> is an empty string, return a promise rejected with a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is <code><a href="#dfn-InvalidAccessError">InvalidAccessError</a></code>.</p></li>
+      <li><p>If this object's <var title="true">session type</var> is not <code><a href="#idl-def-SessionType.persistent">"persistent"</a></code>, return a promise rejected with a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is <code><a href="#dfn-InvalidAccessError">InvalidAccessError</a></code>.</p></li>
       <li><p>Let <var title="true">media keys</var> be the <code><a href="#idl-def-MediaKeys">MediaKeys</a></code> object that created this object.</p></li>
-      <li><p>If the <a href="#cdm">content decryption module</a> corresponding to <var title="true">media keys</var>'s <code><a href="#widl-MediaKeys-keySystem">keySystem</a></code> attribute does not support loading previous sessions, return a promise rejected with a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is <code><a href="#dfn-NotSupportedError">"NotSupportedError"</a></code>.</p></li>
+      <li><p>If the <a href="#cdm">CDM</a> corresponding to <var title="true">media keys</var>'s <code><a href="#widl-MediaKeys-keySystem">keySystem</a></code> attribute does not support loading previous sessions, return a promise rejected with a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is <code><a href="#dfn-NotSupportedError">NotSupportedError</a></code>.</p></li>
       <li><p>Let <var>promise</var> be a new promise.</p></li>
       <li><p>Run the following steps asynchronously:</p>
         <ol>
@@ -1095,7 +1095,7 @@
               At a minimum, this should include checking that the length and value (e.g. alphanumeric) are reasonable.
             </p></div>
           </li>
-          <li><p>If the previous step failed, reject <var>promise</var> with a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is <code><a href="#dfn-InvalidAccessError">"InvalidAccessError"</a></code>.</p></li>
+          <li><p>If the previous step failed, reject <var>promise</var> with a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is <code><a href="#dfn-InvalidAccessError">InvalidAccessError</a></code>.</p></li>
           <li><p>Let <var title="true">expiration time</var> be <code>NaN</code>.</p></li>
           <li><p>Let <var title="true">message</var> be null.</p></li>
           <li><p>Let <var title="true">message type</var> be null.</p></li>
@@ -1105,8 +1105,8 @@
             <ol>
               <li><p>If there is no data stored for the <var>sanitized session ID</var> in the <var title="true">origin</var>, resolve <var>promise</var> with <code>false</code>.</p></li><!-- Per https://github.com/w3ctag/promises-guide#rejections-should-be-used-for-exceptional-situations. -->
               <li><p>Let <var title="true">session data</var> be the data stored for the <var>sanitized session ID</var> in the <var title="true">origin</var>.
-              This must not include data from other origin(s) or that is not associated with an origin.</p></li>
-              <li><p>If there is an unclosed <code><a href="#idl-def-SessionType.persistent">"persistent"</a></code> session in any <a href="http://dom.spec.whatwg.org/#concept-document">Document</a> representing the <var title="true">session data</var>, reject <var>promise</var> with a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is <code><a href="#dfn-QuotaExceededError">"QuotaExceededError"</a></code>.</p>
+              This <em class="rfc2119" title="MUST NOT">MUST NOT</em> include data from other origin(s) or that is not associated with an origin.</p></li>
+              <li><p>If there is an unclosed <code><a href="#idl-def-SessionType.persistent">"persistent"</a></code> session in any <a href="http://dom.spec.whatwg.org/#concept-document">Document</a> representing the <var title="true">session data</var>, reject <var>promise</var> with a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is <code><a href="#dfn-QuotaExceededError">QuotaExceededError</a></code>.</p>
                 <div class="note"><div class="note-title" aria-level="2" role="heading" id="h_note_19"><span>Note</span></div><p class="">In other words, do not create a session if a non-closed persistent session already exists for this <var>sanitized session ID</var> in any browsing context.</p></div>
               </li>
               <li><p>Load the <var title="true">session data</var>.</p></li>
@@ -1122,11 +1122,11 @@
           <li><p>If any of the preceding steps failed, reject <var>promise</var> with a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is the appropriate <a href="#error-names">error name</a>.</p></li>
           <li><p>Set the <code><a href="#widl-MediaKeySession-sessionId">sessionId</a></code> attribute to <var>sanitized session ID</var>.</p></li>
           <li><p>Let this object's <var title="true">callable</var> be true.</p></li>
-          <li><p>If the loaded session contains usable keys, run the <a href="#algorithms-keys-changed">Usable Keys Changed</a> algorithm on the <var title="true">session</var>.</p>
-            <p>The algorithm may also be run later should additional processing be necessary to determine with certainty whether one or more keys is usable.</p>
+          <li><p>If the loaded session contains usable keys, run the <a href="#algorithms-keys-changed">usable keys changed algorithm</a> on the <var title="true">session</var>.</p>
+            <p>The algorithm <em class="rfc2119" title="MAY">MAY</em> also be run later should additional processing be necessary to determine with certainty whether one or more keys is usable.</p>
           </li>
-          <li><p>Run the <a href="#algorithms-update-expiration">Update Expiration</a> algorithm on the <var title="true">session</var>, providing <var title="true">expiration time</var>.</p></li>
-          <li><p>If <var title="true">message</var> is not null, run the <a href="#algorithms-queue-message">Queue a "message" Event</a> algorithm on the <var title="true">session</var>, providing <var title="true">message type</var> and <var title="true">message</var>.</p></li>
+          <li><p>Run the <a href="#algorithms-update-expiration">update expiration algorithm</a> on the <var title="true">session</var>, providing <var title="true">expiration time</var>.</p></li>
+          <li><p>If <var title="true">message</var> is not null, run the <a href="#algorithms-queue-message">queue a "message" event algorithm</a> on the <var title="true">session</var>, providing <var title="true">message type</var> and <var title="true">message</var>.</p></li>
           <li><p>Resolve <var>promise</var> with <code>true</code>.</p></li>
         </ol>
       </li>
@@ -1136,9 +1136,9 @@
 
     
       <div><em>No parameters.</em></div><div><em>Return type: </em><code>Promise&lt;void&gt;</code></div><p>When this method is invoked, the user agent must run the following steps:</p><ol class="method-algorithm">
-      <li><p>If this object's <var title="true">callable</var> value is false, return a promise rejected with a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is <code><a href="#dfn-InvalidStateError">"InvalidStateError"</a></code>.</p></li>
-      <li><p>If this object's <var title="true">session type</var> is not <code><a href="#idl-def-SessionType.persistent">"persistent"</a></code>, return a promise rejected with a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is <code><a href="#dfn-InvalidAccessError">"InvalidAccessError"</a></code>.</p></li>
-      <li><p>If the <a href="#algorithms-session-close">Session Close</a> algorithm has been run on this object, return a promise rejected with a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is <code><a href="#dfn-InvalidStateError">"InvalidStateError"</a></code>.</p></li>
+      <li><p>If this object's <var title="true">callable</var> value is false, return a promise rejected with a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is <code><a href="#dfn-InvalidStateError">InvalidStateError</a></code>.</p></li>
+      <li><p>If this object's <var title="true">session type</var> is not <code><a href="#idl-def-SessionType.persistent">"persistent"</a></code>, return a promise rejected with a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is <code><a href="#dfn-InvalidAccessError">InvalidAccessError</a></code>.</p></li>
+      <li><p>If the <a href="#algorithms-session-close">session close algorithm</a> has been run on this object, return a promise rejected with a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is <code><a href="#dfn-InvalidStateError">InvalidStateError</a></code>.</p></li>
       <li><p>Let <var>promise</var> be a new promise.</p></li>
       <li><p>Run the following steps asynchronously:</p>
         <ol>
@@ -1147,8 +1147,8 @@
             <ol>
               <li>
                 <p>Process the remove request.</p>
-                <p>This may involve exchanging message(s) with the application.</p>
-                <p>Unless this step fails, the CDM must have cleared all stored session data associated with this object, including the <code><a href="#widl-MediaKeySession-sessionId">sessionId</a></code>, before proceeding to the next step.</p>
+                <p>This <em class="rfc2119" title="MAY">MAY</em> involve exchanging message(s) with the application.</p>
+                <p>Unless this step fails, the CDM <em class="rfc2119" title="MUST">MUST</em> have cleared all stored session data associated with this object, including the <code><a href="#widl-MediaKeySession-sessionId">sessionId</a></code>, before proceeding to the next step.</p>
                 <div class="note"><div class="note-title" aria-level="2" role="heading" id="h_note_20"><span>Note</span></div><p class="">A subsequent call to <code><a href="#widl-MediaKeySession-load-Promise-boolean--DOMString-sessionId">load()</a></code> with the value <code><a href="#widl-MediaKeySession-sessionId">sessionId</a></code> would fail because there is no data stored for that session ID.)</p></div>
               </li>
             </ol>
@@ -1156,7 +1156,7 @@
           <li><p>Run the following steps asynchronously once the above step has completed:</p>
             <ol>
               <li><p>If any of the preceding steps failed, reject <var>promise</var> with a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is the appropriate <a href="#error-names">error name</a>.</p></li>
-              <li><p>Run the <a href="#algorithms-session-close">Session Close</a> algorithm on this object.</p></li>
+              <li><p>Run the <a href="#algorithms-session-close">session close algorithm</a> on this object.</p></li>
               <li><p>Resolve <var>promise</var>.</p></li>
             </ol>
           </li>
@@ -1165,12 +1165,12 @@
       <li><p>Return <var>promise</var>.</p></li>
     </ol></dd><dt id="widl-MediaKeySession-update-Promise-void--ArrayBuffer-ArrayBufferView-response"><code>update</code></dt><dd>
     <p>Provides messages, including licenses, to the CDM.</p>
-    <div class="note"><div class="note-title" aria-level="2" role="heading" id="h_note_21"><span>Note</span></div><p class="">The contents of <var title="true">response</var> are <var title="true"><a href="#key-system">keySystem</a></var>-specific.</p></div>
+    <div class="note"><div class="note-title" aria-level="2" role="heading" id="h_note_21"><span>Note</span></div><p class="">The contents of <var title="true">response</var> are <a href="#key-system">Key System</a>-specific.</p></div>
 
     
       <table class="parameters"><tbody><tr><th>Parameter</th><th>Type</th><th>Nullable</th><th>Optional</th><th>Description</th></tr><tr><td class="prmName">response</td><td class="prmType"><code>(ArrayBuffer or ArrayBufferView)</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc"></td></tr></tbody></table><div><em>Return type: </em><code>Promise&lt;void&gt;</code></div><p>When this method is invoked, the user agent must run the following steps:</p><ol class="method-algorithm">
-      <li><p>If this object's <var title="true">callable</var> value is false, return a promise rejected with a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is <code><a href="#dfn-InvalidStateError">"InvalidStateError"</a></code>.</p></li>
-      <li><p>If <var title="true">response</var> is an empty array, return a promise rejected with a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is <code><a href="#dfn-InvalidAccessError">"InvalidAccessError"</a></code>.</p></li>
+      <li><p>If this object's <var title="true">callable</var> value is false, return a promise rejected with a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is <code><a href="#dfn-InvalidStateError">InvalidStateError</a></code>.</p></li>
+      <li><p>If <var title="true">response</var> is an empty array, return a promise rejected with a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is <code><a href="#dfn-InvalidAccessError">InvalidAccessError</a></code>.</p></li>
       <li><p>Let <var>response copy</var> be a copy of the contents of the <var title="true">response</var> parameter.</p></li>
       <li><p>Let <var>promise</var> be a new promise.</p></li>
       <li><p>Run the following steps asynchronously:</p>
@@ -1182,36 +1182,36 @@
               Unknown fields should be rejected or removed.
             </p></div>
           </li>
-          <li><p>If the previous step failed, reject <var>promise</var> with a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is <code><a href="#dfn-InvalidAccessError">"InvalidAccessError"</a></code>.</p></li>
+          <li><p>If the previous step failed, reject <var>promise</var> with a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is <code><a href="#dfn-InvalidAccessError">InvalidAccessError</a></code>.</p></li>
           <li><p>Let <var title="true">cdm</var> be the CDM loaded during the <a href="#widl-MediaKeys-create-Promise-MediaKeys--DOMString-keySystem">initialization</a> of the <code><a href="#idl-def-MediaKeys">MediaKeys</a></code> object that created this object.</p></li>
           <li><p>Let <var title="true">message</var> be null.</p></li>
           <li><p>Let <var title="true">message type</var> be null.</p></li>
           <li><p>Use the <var title="true">cdm</var> to execute the following steps:</p>
             <ol>
-              <li><p>If the format of <var>sanitized response</var> is invalid in any way, reject <var>promise</var> with a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is <code><a href="#dfn-InvalidAccessError">"InvalidAccessError"</a></code>.</p></li>
+              <li><p>If the format of <var>sanitized response</var> is invalid in any way, reject <var>promise</var> with a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is <code><a href="#dfn-InvalidAccessError">InvalidAccessError</a></code>.</p></li>
               <li><p>Process <var>sanitized response</var>, following the stipulation for the first matching condition from the following list:</p>
                 <dl class="switch">
                   <dt>If <var title="true">sessionType</var> is <code><a href="#idl-def-SessionType.temporary">"temporary"</a></code> and <var>sanitized response</var> does not specify that session data, including any license, key(s), or similar session data it contains, should be stored</dt>
                   <dd>Continue processing <var>sanitized response</var>, not storing any session data.</dd>
                   <dt>If <var title="true">sessionType</var> is <code><a href="#idl-def-SessionType.persistent">"persistent"</a></code></dt>
                   <dd>Continue processing <var>sanitized response</var>, storing the license, key(s), or similar session data contained in <var>sanitized response</var> as permitted or instructed by the license.
-                    Such data must be stored such that only the <a href="http://www.w3.org/TR/html5/browsers.html#origin-0">origin</a> of this object's <a href="http://dom.spec.whatwg.org/#concept-document">Document</a> can access it.
+                    Such data <em class="rfc2119" title="MUST">MUST</em> be stored such that only the <a href="http://www.w3.org/TR/html5/browsers.html#origin-0">origin</a> of this object's <a href="http://dom.spec.whatwg.org/#concept-document">Document</a> can access it.
                   </dd>
                   <dt>Otherwise</dt>
-                  <dd>Reject <var>promise</var> with a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is <code><a href="#dfn-InvalidAccessError">"InvalidAccessError"</a></code>.</dd>
+                  <dd>Reject <var>promise</var> with a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is <code><a href="#dfn-InvalidAccessError">InvalidAccessError</a></code>.</dd>
                 </dl>
                 <p>See also <a href="#session-storage">Session Storage and Persistence</a>.</p>
                 <div class="note"><div class="note-title" aria-level="2" role="heading" id="h_note_23"><span>Note</span></div><p class="">When <var>sanitized response</var> contains key(s) and/or related data, <var title="true">cdm</var> will likely cache the key and related data indexed by key ID.</p></div>
                 <div class="note"><div class="note-title" aria-level="2" role="heading" id="h_note_24"><span>Note</span></div><p class="">The replacement algorithm within a session is <a href="#key-system">Key System</a>-dependent.</p></div>
-                <div class="note"><div class="note-title" aria-level="2" role="heading" id="h_note_25"><span>Note</span></div><p class="">Keys from different sessions should be cached independently such that closing one session does not affect keys in other sessions, even if they have overlapping key IDs.</p></div>
-                <div class="note"><div class="note-title" aria-level="2" role="heading" id="h_note_26"><span>Note</span></div><p class="">It is recommended that CDMs support a standard and reasonably high minimum number of keys per <code><a href="#idl-def-MediaKeySession">MediaKeySession</a></code> object, including a standard replacement algorithm, and a standard and reasonably high minimum number of <code><a href="#idl-def-MediaKeySession">MediaKeySession</a></code> objects.
+                <p>Keys from different sessions <em class="rfc2119" title="SHOULD">SHOULD</em> be cached independently such that closing one session does not affect keys in other sessions, even if they have overlapping key IDs.</p>
+                <div class="note"><div class="note-title" aria-level="2" role="heading" id="h_note_25"><span>Note</span></div><p class="">It is <em class="rfc2119" title="RECOMMENDED">RECOMMENDED</em> that CDMs support a standard and reasonably high minimum number of keys per <code><a href="#idl-def-MediaKeySession">MediaKeySession</a></code> object, including a standard replacement algorithm, and a standard and reasonably high minimum number of <code><a href="#idl-def-MediaKeySession">MediaKeySession</a></code> objects.
                 This enables a reasonable number of key rotation algorithms to be implemented across user agents and may reduce the likelihood of playback interruptions in use cases that involve various streams in the same element (i.e. adaptive streams, various audio and video tracks) using different keys.
                 </p></div>
               </li> 
-              <li><p>If the set of usable keys changed, run the <a href="#algorithms-keys-changed">Usable Keys Changed</a> algorithm on the <var title="true">session</var>.</p>
-                <p>The algorithm may also be run later should additional processing be necessary to determine with certainty whether one or more keys is usable.</p>
+              <li><p>If the set of usable keys changed, run the <a href="#algorithms-keys-changed">usable keys changed algorithm</a> on the <var title="true">session</var>.</p>
+                <p>The algorithm <em class="rfc2119" title="MAY">MAY</em> also be run later should additional processing be necessary to determine with certainty whether one or more keys is usable.</p>
               </li>
-              <li><p>If the expiration time for the session changed, run the <a href="#algorithms-update-expiration">Update Expiration</a> algorithm on the <var title="true">session</var>, providing the new expiration time.</p></li>
+              <li><p>If the expiration time for the session changed, run the <a href="#algorithms-update-expiration">update expiration algorithm</a> on the <var title="true">session</var>, providing the new expiration time.</p></li>
               <li><p>If a message needs to be sent to the server, execute the following steps:</p>
                 <ol>
                   <li><p>Let <var title="true">message</var> be that message.</p></li>
@@ -1221,7 +1221,7 @@
             </ol>
           </li>
           <li><p>If any of the preceding steps failed, reject <var>promise</var> with a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is the appropriate <a href="#error-names">error name</a>.</p></li>
-          <li><p>If <var title="true">message</var> is not null, run the <a href="#algorithms-queue-message">Queue a "message" Event</a> algorithm on the <var title="true">session</var>, providing <var title="true">message type</var> and <var title="true">message</var>.</p></li>
+          <li><p>If <var title="true">message</var> is not null, run the <a href="#algorithms-queue-message">queue a "message" event algorithm</a> on the <var title="true">session</var>, providing <var title="true">message type</var> and <var title="true">message</var>.</p></li>
           <li><p>Resolve <var>promise</var>.</p></li>
         </ol>
       </li>
@@ -1267,7 +1267,7 @@
     <section id="mediakeysession-events" class="informative" typeof="bibo:Chapter" resource="#mediakeysession-events" rel="bibo:Chapter">
     <h3 role="heading" id="h3_mediakeysession-events"><span class="secno">3.4 </span>Event Summary</h3><p><em>This section is non-normative.</em></p>
 
-    <div class="note"><div class="note-title" aria-level="2" role="heading" id="h_note_27"><span>Note</span></div><p class="">In some implementations, <code><a href="#idl-def-MediaKeySession">MediaKeySession</a></code> objects may not fire any events until the <code><a href="#idl-def-MediaKeys">MediaKeys</a></code> object is associated with a media element using <code><a href="#widl-HTMLMediaElement-setMediaKeys-Promise-void--MediaKeys-mediaKeys">setMediaKeys()</a></code>.</p></div>
+    <div class="note"><div class="note-title" aria-level="2" role="heading" id="h_note_26"><span>Note</span></div><p class="">In some implementations, <code><a href="#idl-def-MediaKeySession">MediaKeySession</a></code> objects may not fire any events until the <code><a href="#idl-def-MediaKeys">MediaKeys</a></code> object is associated with a media element using <code><a href="#widl-HTMLMediaElement-setMediaKeys-Promise-void--MediaKeys-mediaKeys">setMediaKeys()</a></code>.</p></div>
 
     <table class="old-table">
       <thead>
@@ -1324,9 +1324,9 @@
     <ol>
       <li><p>Let the <var title="true">session</var> be the associated <code><a href="#idl-def-MediaKeySession">MediaKeySession</a></code> object.</p></li>
       <li><p><a href="http://www.w3.org/TR/html5/webappapis.html#queue-a-task">Queue a task</a> to <a href="http://www.w3.org/TR/html5/webappapis.html#fire-a-simple-event">fire a simple event</a> named <code><a href="#dom-evt-keyschange">keyschange</a></code> at the <var title="true">session</var>.</p></li>
-      <li><p><a href="http://www.w3.org/TR/html5/webappapis.html#queue-a-task">Queue a task</a> to run the <a href="#algorithms-resume-playback">Attempt to Resume Playback If Necessary</a> algorithm on each of the <a href="#htmlmediaelement-extensions">media element(s)</a> whose <code><a href="#widl-HTMLMediaElement-mediaKeys">mediaKeys</a></code> attribute is the MediaKeys object that created the <var title="true">session</var>.</p>
-        <p>The user agent may choose to skip this step if it knows resuming will fail.</p>
-        <div class="note"><div class="note-title" aria-level="3" role="heading" id="h_note_28"><span>Note</span></div><p class="">For example, the user agenet may skip this step if no additional keys became available.</p></div>
+      <li><p><a href="http://www.w3.org/TR/html5/webappapis.html#queue-a-task">Queue a task</a> to run the <a href="#algorithms-resume-playback">attempt to resume playback if necessary algorithm</a> on each of the media element(s) whose <code><a href="#widl-HTMLMediaElement-mediaKeys">mediaKeys</a></code> attribute is the MediaKeys object that created the <var title="true">session</var>.</p>
+        <p>The user agent <em class="rfc2119" title="MAY">MAY</em> choose to skip this step if it knows resuming will fail.</p>
+        <div class="note"><div class="note-title" aria-level="3" role="heading" id="h_note_27"><span>Note</span></div><p class="">For example, the user agent may skip this step if no additional keys became available.</p></div>
       </li>
     </ol>
     </section>
@@ -1349,8 +1349,8 @@
     <section id="algorithms-session-close" typeof="bibo:Chapter" resource="#algorithms-session-close" rel="bibo:Chapter">
     <h4 role="heading" id="h4_algorithms-session-close"><span class="secno">3.5.4 </span>Session Close</h4>
     <p>The Session Close algorithm is run when the CDM closes the session associated with a <code><a href="#idl-def-MediaKeySession">MediaKeySession</a></code> object.</p>
-    <div class="note"><div class="note-title" aria-level="3" role="heading" id="h_note_29"><span>Note</span></div><p class="">The CDM may close a session at any point, such as in response to a <code><a href="#widl-MediaKeySession-close-Promise-void">close()</a></code> call, when the session is no longer needed, or when system resources are lost.
-    Keys in other sessions should be unaffected, even if they have overlapping key IDs.
+    <div class="note"><div class="note-title" aria-level="3" role="heading" id="h_note_28"><span>Note</span></div><p class="">The CDM may close a session at any point, such as in response to a <code><a href="#widl-MediaKeySession-close-Promise-void">close()</a></code> call, when the session is no longer needed, or when system resources are lost.
+    Keys in other sessions <em class="rfc2119" title="SHOULD">SHOULD</em> be unaffected, even if they have overlapping key IDs.
     </p></div>
     <p>The following steps are run:</p>
     <ol>
@@ -1366,7 +1366,7 @@
     <h3 role="heading" id="h3_exceptions"><span class="secno">3.6 </span>Exceptions</h3>
     <p id="error-names">The methods report errors by rejecting the returned promise with a <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code>.
     The following <a href="http://heycam.github.io/webidl/#idl-DOMException-error-names">DOMException names from WebIDL</a> are used in the algorithms.
-    Causes specified specified in the algorithms are listed alongside each name, though these names may be used for other reasons as well. 
+    Causes specified specified in the algorithms are listed alongside each name, though these names <em class="rfc2119" title="MAY">MAY</em> be used for other reasons as well.
     </p>
 
     <table class="old-table">
@@ -1418,25 +1418,25 @@
     <section id="session-storage" typeof="bibo:Chapter" resource="#session-storage" rel="bibo:Chapter">
     <h3 role="heading" id="h3_session-storage"><span class="secno">3.7 </span>Session Storage and Persistence</h3>
     <p>This section provides an overview of session stroage and persistence that complements the algorithms.</p>
-    <p>If this object's <var title="true">session type</var> is not <code><a href="#idl-def-SessionType.persistent">"persistent"</a></code>, the user agent and CDM must <em>not</em> persist a record of or data related to the session at any point.
-      This includes license(s), key(s), and the <a href="#session-id">Session ID</a>.
+    <p>If this object's <var title="true">session type</var> is not <code><a href="#idl-def-SessionType.persistent">"persistent"</a></code>, the user agent and CDM <em class="rfc2119" title="MUST NOT">MUST NOT</em> persist a record of or data related to the session at any point.
+      This includes license(s), key(s), and the <a href="#session-id">Session Id</a>.
     </p>
-    <p>The remainder of this section applies to <code><a href="#idl-def-SessionType.persistent">"persistent"</a></code> sessions, which implementatations may optionally support.</p>
-    <p>Persisted data must always be stored such that only the <a href="http://www.w3.org/TR/html5/browsers.html#origin-0">origin</a> of this object's <a href="http://dom.spec.whatwg.org/#concept-document">Document</a> can access it.
-      In addition, the data must only be accessible by the current profile of this user agent - other user agent profiles, user agents, and applications must not be able to access the stored data.
+    <p>The remainder of this section applies to <code><a href="#idl-def-SessionType.persistent">"persistent"</a></code> sessions, which are <em class="rfc2119" title="OPTIONAL">OPTIONAL</em> for implementatations to support.</p>
+    <p>Persisted data <em class="rfc2119" title="MUST">MUST</em> always be stored such that only the <a href="http://www.w3.org/TR/html5/browsers.html#origin-0">origin</a> of this object's <a href="http://dom.spec.whatwg.org/#concept-document">Document</a> can access it.
+      In addition, the data <em class="rfc2119" title="MUST">MUST</em> only be accessible by the current profile of this user agent - other user agent profiles, user agents, and applications <em class="rfc2119" title="MUST NOT">MUST NOT</em> be able to access the stored data.
     </p>
-    <p>The CDM should not store session data, including the Session ID, until <code><a href="#widl-MediaKeySession-update-Promise-void--ArrayBuffer-ArrayBufferView-response">update()</a></code> is called the first time.
-      Specifically, the CDM should not store session data during the <code><a href="#widl-MediaKeySession-generateRequest-Promise-void--DOMString-initDataType-ArrayBuffer-ArrayBufferView-initData">generateRequest()</a></code> algorithm.
+    <p>The CDM <em class="rfc2119" title="SHOULD NOT">SHOULD NOT</em> store session data, including the Session ID, until <code><a href="#widl-MediaKeySession-update-Promise-void--ArrayBuffer-ArrayBufferView-response">update()</a></code> is called the first time.
+      Specifically, the CDM <em class="rfc2119" title="SHOULD NOT">SHOULD NOT</em> store session data during the <code><a href="#widl-MediaKeySession-generateRequest-Promise-void--DOMString-initDataType-ArrayBuffer-ArrayBufferView-initData">generateRequest()</a></code> algorithm.
       This ensures that the application is aware of the session and knows it needs to eventually remove it.
     </p>
-    <p>The CDM must ensure that data for a given session is only present in one active unclosed session in any <a href="http://dom.spec.whatwg.org/#concept-document">Document</a>.
-      In other words, <code><a href="#widl-MediaKeySession-load-Promise-boolean--DOMString-sessionId">load()</a></code> must fail when there is already a <code><a href="#idl-def-MediaKeySession">MediaKeySession</a></code> representing the session specified by the <var title="true">sessionId</var> parameter, either because the object that created it via <code><a href="#widl-MediaKeySession-generateRequest-Promise-void--DOMString-initDataType-ArrayBuffer-ArrayBufferView-initData">generateRequest()</a></code> is still active or it has been loaded into another object via <code><a href="#widl-MediaKeySession-load-Promise-boolean--DOMString-sessionId">load()</a></code>.
-      A session may only be loaded again after the <a href="#algorithms-session-close">Session Close</a> algorithm has not been run on the object representing it.
+    <p>The CDM <em class="rfc2119" title="MUST">MUST</em> ensure that data for a given session is only present in one active unclosed session in any <a href="http://dom.spec.whatwg.org/#concept-document">Document</a>.
+      In other words, <code><a href="#widl-MediaKeySession-load-Promise-boolean--DOMString-sessionId">load()</a></code> <em class="rfc2119" title="MUST">MUST</em> fail when there is already a <code><a href="#idl-def-MediaKeySession">MediaKeySession</a></code> representing the session specified by the <var title="true">sessionId</var> parameter, either because the object that created it via <code><a href="#widl-MediaKeySession-generateRequest-Promise-void--DOMString-initDataType-ArrayBuffer-ArrayBufferView-initData">generateRequest()</a></code> is still active or it has been loaded into another object via <code><a href="#widl-MediaKeySession-load-Promise-boolean--DOMString-sessionId">load()</a></code>.
+      A session <em class="rfc2119" title="MAY">MAY</em> only be loaded again after the <a href="#algorithms-session-close">session close algorithm</a> has not been run on the object representing it.
     </p>
-    <p>An application that creates a <code><a href="#idl-def-SessionType.persistent">"persistent"</a></code> session should later remove the stored data using <code><a href="#widl-MediaKeySession-remove-Promise-void">remove()</a></code>.
-      The CDM may also remove sessions as appropriate, but applications should not rely on this.
+    <p>An application that creates a <code><a href="#idl-def-SessionType.persistent">"persistent"</a></code> session <em class="rfc2119" title="SHOULD">SHOULD</em> later remove the stored data using <code><a href="#widl-MediaKeySession-remove-Promise-void">remove()</a></code>.
+      The CDM <em class="rfc2119" title="MAY">MAY</em> also remove sessions as appropriate, but applications <em class="rfc2119" title="SHOULD NOT">SHOULD NOT</em> rely on this.
     </p>
-    <div class="note"><div class="note-title" aria-level="2" role="heading" id="h_note_30"><span>Note</span></div><p class="">See the <a href="#security">Security Considerations</a> and <a href="#privacy">Privacy Considerations</a> sections for additional considerations when supporting persistent storage.</p></div>
+    <div class="note"><div class="note-title" aria-level="2" role="heading" id="h_note_29"><span>Note</span></div><p class="">See the <a href="#security">Security Considerations</a> and <a href="#privacy">Privacy Considerations</a> sections for additional considerations when supporting persistent storage.</p></div>
     </section>
     </section>
 
@@ -1466,32 +1466,32 @@
 <span class="idlAttribute">                attribute <span class="idlAttrType">EventHandler</span>    <span class="idlAttrName"><a href="#widl-HTMLMediaElement-onencrypted">onencrypted</a></span>;</span>
 <span class="idlMethod">    <span class="idlMethType">Promise&lt;void&gt;</span> <span class="idlMethName"><a href="#widl-HTMLMediaElement-setMediaKeys-Promise-void--MediaKeys-mediaKeys">setMediaKeys</a></span> (<span class="idlParam"><span class="idlParamType"><a href="#idl-def-MediaKeys" class="idlType"><code>MediaKeys</code></a>?</span> <span class="idlParamName">mediaKeys</span></span>);</span>
 };</span></pre><section id="attributes-3"><h3 role="heading" id="h3_attributes-3"><span class="secno">4.1 </span>Attributes</h3><dl class="attributes"><dt id="widl-HTMLMediaElement-mediaKeys"><code>mediaKeys</code> of type <span class="idlAttrType"><a href="#idl-def-MediaKeys" class="idlType"><code>MediaKeys</code></a></span>, readonly   , nullable</dt><dd>
-        <p>The <code><a href="#idl-def-MediaKeys">MediaKeys</a></code> being used when decrypting encrypted <a href="http://www.w3.org/TR/html5/embedded-content-0.html#media-data">media data</a> for this <a href="#htmlmediaelement-extensions">media element</a>.</p>
+        <p>The <code><a href="#idl-def-MediaKeys">MediaKeys</a></code> being used when decrypting encrypted <a href="http://www.w3.org/TR/html5/embedded-content-0.html#media-data">media data</a> for this media element.</p>
       </dd><dt id="widl-HTMLMediaElement-onencrypted"><code>onencrypted</code> of type <span class="idlAttrType">EventHandler</span>,            </dt><dd>
-        <p>Event handler for the <code><a href="#dom-evt-encrypted">encrypted</a></code> event must be supported by all HTMLMediaElements as both a content attribute and an IDL attribute.</p>
+        <p>Event handler for the <code><a href="#dom-evt-encrypted">encrypted</a></code> event <em class="rfc2119" title="MUST">MUST</em> be supported by all HTMLMediaElements as both a content attribute and an IDL attribute.</p>
       </dd><dt id="widl-HTMLMediaElement-waitingFor"><code>waitingFor</code> of type <span class="idlAttrType"><a href="#idl-def-MediaWaitingFor" class="idlType"><code>MediaWaitingFor</code></a></span>, readonly   </dt><dd>
-        <p>Indicates what the media element is waiting for, if anything (indicated by the <code><a href="http://www.w3.org/TR/html5/embedded-content-0.html#event-media-waiting">waiting</a></code> and <code><a href="http://www.w3.org/TR/html5/embedded-content-0.html#event-media-canplay">canplay</a></code> events). This is described in the <a href="#algorithms-encrypted-block">Encrypted Block Encountered</a> algorithm.</p>
+        <p>Indicates what the media element is waiting for, if anything (indicated by the <code><a href="http://www.w3.org/TR/html5/embedded-content-0.html#event-media-waiting">waiting</a></code> and <code><a href="http://www.w3.org/TR/html5/embedded-content-0.html#event-media-canplay">canplay</a></code> events). This is described in the <a href="#algorithms-encrypted-block">encrypted block encountered algorithm</a>.</p>
       </dd></dl></section><section id="methods-2"><h3 role="heading" id="h3_methods-2"><span class="secno">4.2 </span>Methods</h3><dl class="methods"><dt id="widl-HTMLMediaElement-setMediaKeys-Promise-void--MediaKeys-mediaKeys"><code>setMediaKeys</code></dt><dd>
     <p>Provides the <code><a href="#idl-def-MediaKeys">MediaKeys</a></code> to use when decrypting media data during playback.</p>
 
     
     
-    <div class="note"><div class="note-title" aria-level="2" role="heading" id="h_note_33"><span>Note</span></div><p class="">Support for clearing or replacing the associated <code><a href="#idl-def-MediaKeys">MediaKeys</a></code> object during playback is a quality of implementation issue. In many cases it will result in a bad user experience or rejected promise.</p></div>
-    <div class="note"><div class="note-title" aria-level="2" role="heading" id="h_note_34"><span>Note</span></div><p class="">As a best practice, applications should create a MediaKeys object and call <code><a href="#widl-HTMLMediaElement-setMediaKeys-Promise-void--MediaKeys-mediaKeys">setMediaKeys()</a></code> before providing <a href="http://www.w3.org/TR/html5/embedded-content-0.html#media-data">media data</a> (for example, setting the <code><a href="http://www.w3.org/TR/html5/embedded-content-0.html#attr-media-src">src</a></code> attribute). This avoids potential delays in some implementations.</p></div>
+    <div class="note"><div class="note-title" aria-level="2" role="heading" id="h_note_32"><span>Note</span></div><p class="">Support for clearing or replacing the associated <code><a href="#idl-def-MediaKeys">MediaKeys</a></code> object during playback is a quality of implementation issue. In many cases it will result in a bad user experience or rejected promise.</p></div>
+    <div class="note"><div class="note-title" aria-level="2" role="heading" id="h_note_33"><span>Note</span></div><p class="">As a best practice, applications should create a MediaKeys object and call <code><a href="#widl-HTMLMediaElement-setMediaKeys-Promise-void--MediaKeys-mediaKeys">setMediaKeys()</a></code> before providing <a href="http://www.w3.org/TR/html5/embedded-content-0.html#media-data">media data</a> (for example, setting the <code><a href="http://www.w3.org/TR/html5/embedded-content-0.html#attr-media-src">src</a></code> attribute). This avoids potential delays in some implementations.</p></div>
       <table class="parameters"><tbody><tr><th>Parameter</th><th>Type</th><th>Nullable</th><th>Optional</th><th>Description</th></tr><tr><td class="prmName">mediaKeys</td><td class="prmType"><code><a href="#idl-def-MediaKeys" class="idlType"><code>MediaKeys</code></a></code></td><td class="prmNullTrue"><span role="img" aria-label="True">✔</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc"></td></tr></tbody></table><div><em>Return type: </em><code>Promise&lt;void&gt;</code></div><p>When this method is invoked, the user agent must run the following steps:</p><ol class="method-algorithm">
       <!-- For simplicity and consistency, do not allow multiple pending calls. -->
       <li><p>If <var>mediaKeys</var> and the <code><a href="#widl-HTMLMediaElement-mediaKeys">mediaKeys</a></code> attribute are the same object, return a resolved promise.</p></li>
-      <li><p>If this object's <var title="true">attaching media keys</var> value is true, return a promise rejected with a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is <code><a href="#dfn-InvalidStateError">"InvalidStateError"</a></code>.</p></li>
+      <li><p>If this object's <var title="true">attaching media keys</var> value is true, return a promise rejected with a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is <code><a href="#dfn-InvalidStateError">InvalidStateError</a></code>.</p></li>
       <li><p>Let this object's <var title="true">attaching media keys</var> value be true.</p></li>
       <li><p>Let <var>promise</var> be a new promise.</p></li>
       <li><p>Run the following steps asynchronously:</p>
         <ol>
-          <li><p>If <var>mediaKeys</var> is not null, it is already in use by another media element, and the user agent is unable to use it with this element, let this object's <var title="true">attaching media keys</var> value be false and reject <var>promise</var> with a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is <code><a href="#dfn-QuotaExceededError">"QuotaExceededError"</a></code>.</p></li>
+          <li><p>If <var>mediaKeys</var> is not null, it is already in use by another media element, and the user agent is unable to use it with this element, let this object's <var title="true">attaching media keys</var> value be false and reject <var>promise</var> with a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is <code><a href="#dfn-QuotaExceededError">QuotaExceededError</a></code>.</p></li>
           <li><p>If the <code><a href="#widl-HTMLMediaElement-mediaKeys">mediaKeys</a></code> attribute is not null, run the following steps:</p>
             <ol>
-              <li><p>If the user agent or CDM do not support removing the association, let this object's <var title="true">attaching media keys</var> value be false and reject <var>promise</var> with a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is <code><a href="#dfn-NotSupportedError">"NotSupportedError"</a></code>.</p></li>
-              <li><p>If the association cannot currently be removed, let this object's <var title="true">attaching media keys</var> value be false and reject <var>promise</var> with a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is <code><a href="#dfn-InvalidStateError">"InvalidStateError"</a></code>.</p>
-                <div class="note"><div class="note-title" aria-level="2" role="heading" id="h_note_31"><span>Note</span></div><p class="">For example, some implementations may not allow removal during playback.</p></div>
+              <li><p>If the user agent or CDM do not support removing the association, let this object's <var title="true">attaching media keys</var> value be false and reject <var>promise</var> with a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is <code><a href="#dfn-NotSupportedError">NotSupportedError</a></code>.</p></li>
+              <li><p>If the association cannot currently be removed, let this object's <var title="true">attaching media keys</var> value be false and reject <var>promise</var> with a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is <code><a href="#dfn-InvalidStateError">InvalidStateError</a></code>.</p>
+                <div class="note"><div class="note-title" aria-level="2" role="heading" id="h_note_30"><span>Note</span></div><p class="">For example, some implementations may not allow removal during playback.</p></div>
               </li>
               <li><p>Stop using the CDM instance represented by the <code><a href="#widl-HTMLMediaElement-mediaKeys">mediaKeys</a></code> attribute to decrypt <a href="http://www.w3.org/TR/html5/embedded-content-0.html#media-data">media data</a> and remove the association with the media element.</p></li>
               <li><p>If the preceding step failed, let this object's <var title="true">attaching media keys</var> value be false and reject <var>promise</var> with a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is the appropriate <a href="#error-names">error name</a>.</p></li>
@@ -1507,9 +1507,9 @@
                   <li><p>Reject <var>promise</var> with a new <code><a href="http://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code> whose name is the appropriate <a href="#error-names">error name</a>.</p></li>
                 </ol>
               </li>
-              <li><p><a href="http://www.w3.org/TR/html5/webappapis.html#queue-a-task">Queue a task</a> to run the <a href="#algorithms-resume-playback">Attempt to Resume Playback If Necessary</a> algorithm on the media element.</p>
-                <p>The user agent may choose to skip this step if it knows resuming will fail.</p><p>
-                </p><div class="note"><div class="note-title" aria-level="2" role="heading" id="h_note_32"><span>Note</span></div><p class="">For example, the user agenet may skip this step if <var>mediaKeys</var> has no sessions.</p></div>
+              <li><p><a href="http://www.w3.org/TR/html5/webappapis.html#queue-a-task">Queue a task</a> to run the <a href="#algorithms-resume-playback">attempt to resume playback if necessary algorithm</a> on the media element.</p>
+                <p>The user agent <em class="rfc2119" title="MAY">MAY</em> choose to skip this step if it knows resuming will fail.</p><p>
+                </p><div class="note"><div class="note-title" aria-level="2" role="heading" id="h_note_31"><span>Note</span></div><p class="">For example, the user agent may skip this step if <var>mediaKeys</var> has no sessions.</p></div>
               </li>
             </ol>
           </li>
@@ -1535,7 +1535,7 @@
         <table class="parameters"><tbody><tr><th>Parameter</th><th>Type</th><th>Nullable</th><th>Optional</th><th>Description</th></tr><tr><td class="prmName">type</td><td class="prmType"><code>DOMString</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc"></td></tr><tr><td class="prmName">eventInitDict</td><td class="prmType"><code><a href="#idl-def-MediaEncryptedEventInit" class="idlType"><code>MediaEncryptedEventInit</code></a></code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptTrue"><span role="img" aria-label="True">✔</span></td><td class="prmDesc"></td></tr></tbody></table></dd></dl></section><section id="attributes-4"><h4 role="heading" id="h4_attributes-4"><span class="secno">4.3.2 </span>Attributes</h4><dl class="attributes"><dt id="widl-MediaEncryptedEvent-initData"><code>initData</code> of type <span class="idlAttrType">ArrayBuffer</span>, readonly   , nullable</dt><dd>
           The <a href="#initialization-data">Initialization Data</a> for the event.
         </dd><dt id="widl-MediaEncryptedEvent-initDataType"><code>initDataType</code> of type <span class="idlAttrType">DOMString</span>, readonly   </dt><dd>
-          Indicates the <a href="#initialization-data-type">initialization data type</a> of the <a href="#initialization-data">Initialization Data</a> contained in the <code><a href="#widl-MediaEncryptedEventInit-initData">initData</a></code> attribute.
+          Indicates the <a href="#initialization-data">Initialization Data</a> of the <a href="#initialization-data">Initialization Data</a> contained in the <code><a href="#widl-MediaEncryptedEventInit-initData">initData</a></code> attribute.
         </dd></dl></section>
 
       <section id="mediaencryptedeventinit" typeof="bibo:Chapter" resource="#mediaencryptedeventinit" rel="bibo:Chapter">
@@ -1546,7 +1546,7 @@
 };</span></pre><section id="dictionary-mediaencryptedeventinit-members"><h5 role="heading" id="h5_dictionary-mediaencryptedeventinit-members"><span class="secno">4.3.3.1 </span>Dictionary <a class="idlType" href="#idl-def-MediaEncryptedEventInit"><code>MediaEncryptedEventInit</code></a> Members</h5><dl class="dictionary-members"><dt id="widl-MediaEncryptedEventInit-initData"><code>initData</code> of type <span class="idlMemberType">ArrayBuffer</span>, nullable, defaulting to <code>null</code></dt><dd>
             The <a href="#initialization-data">Initialization Data</a>.
           </dd><dt id="widl-MediaEncryptedEventInit-initDataType"><code>initDataType</code> of type <span class="idlMemberType">DOMString</span>, defaulting to <code>""</code></dt><dd>
-            The <a href="#initialization-data-type">initialization data type</a>.
+            The <a href="#initialization-data">Initialization Data</a>.
           </dd></dl></section>
       </section>
     </section>
@@ -1569,7 +1569,7 @@
           <td><a href="#idl-def-MediaEncryptedEvent" class="idlType"><code>MediaEncryptedEvent</code></a></td>
           <td>The user agent encounters <a href="#initialization-data">Initialization Data</a> in the <a href="http://www.w3.org/TR/html5/embedded-content-0.html#media-data">media data</a>.</td>
           <td><code><a href="http://www.w3.org/TR/html5/embedded-content-0.html#dom-media-readystate">readyState</a></code> is equal to <code><a href="http://www.w3.org/TR/html5/embedded-content-0.html#dom-media-have_metadata">HAVE_METADATA</a></code> or greater.
-          <div class="note"><div class="note-title" aria-level="2" role="heading" id="h_note_35"><span>Note</span></div><p class="">It is possible that the element is playing or has played.</p></div>
+          <div class="note"><div class="note-title" aria-level="2" role="heading" id="h_note_34"><span>Note</span></div><p class="">It is possible that the element is playing or has played.</p></div>
           </td>
         </tr>
       </tbody>
@@ -1589,10 +1589,10 @@
       <li>
         <p>If the <a href="http://www.w3.org/TR/html5/embedded-content-0.html#media-data">media data</a> is <a href="http://www.w3.org/TR/html5/infrastructure.html#cors-same-origin">CORS-same-origin</a> and <em>not</em> <a href="#mixed-content">mixed content</a>, run the following steps:</p>
         <ol>
-          <li><p>Let <var title="">initDataType</var> be the string representing the <a href="#initialization-data-type">initialization data type</a> of the Initialization Data.</p></li>
+          <li><p>Let <var title="">initDataType</var> be the string representing the <a href="#initialization-data">Initialization Data</a> of the Initialization Data.</p></li>
           <li><p>Let <var title="">initData</var> be the Initialization Data.</p></li>
         </ol>
-        <div class="note"><div class="note-title" aria-level="3" role="heading" id="h_note_36"><span>Note</span></div><p class="">While the media element may allow loading of "Optionally-blockable Content" [MIXED-CONTENT], the user agent must not expose Initialization Data from such media data to the application.</p></div>
+        <div class="note"><div class="note-title" aria-level="3" role="heading" id="h_note_35"><span>Note</span></div><p class="">While the media element may allow loading of "Optionally-blockable Content" [MIXED-CONTENT], the user agent <em class="rfc2119" title="MUST NOT">MUST NOT</em> expose Initialization Data from such media data to the application.</p></div>
       </li>
       <li>
         <p><a href="http://www.w3.org/TR/html5/webappapis.html#queue-a-task">Queue a task</a> to <a href="http://www.w3.org/TR/html5/webappapis.html#fire-a-simple-event">fire a simple event</a> named <code><a href="#dom-evt-encrypted">encrypted</a></code> at the media element.</p>
@@ -1601,8 +1601,8 @@
           <code><a href="#widl-MediaEncryptedEventInit-initDataType">initDataType</a></code> = <var title="">initDataType</var><br><br>
           <code><a href="#widl-MediaEncryptedEventInit-initData">initData</a></code> = <var title="">initData</var>
         </li></ul>
-        <div class="note"><div class="note-title" aria-level="3" role="heading" id="h_note_37"><span>Note</span></div><p class=""><code><a href="http://www.w3.org/TR/html5/embedded-content-0.html#dom-media-readystate">readyState</a></code> is <em>not</em> changed and no algorithms are aborted. This event merely provides information.</p></div>
-        <div class="note"><div class="note-title" aria-level="3" role="heading" id="h_note_38"><span>Note</span></div><p class="">The <code><a href="#widl-MediaEncryptedEventInit-initData">initData</a></code> attribute will be null if the media data is <em>not</em> <a href="http://www.w3.org/TR/html5/infrastructure.html#cors-same-origin">CORS-same-origin</a> or is <a href="#mixed-content">mixed content</a>.
+        <div class="note"><div class="note-title" aria-level="3" role="heading" id="h_note_36"><span>Note</span></div><p class=""><code><a href="http://www.w3.org/TR/html5/embedded-content-0.html#dom-media-readystate">readyState</a></code> is <em>not</em> changed and no algorithms are aborted. This event merely provides information.</p></div>
+        <div class="note"><div class="note-title" aria-level="3" role="heading" id="h_note_37"><span>Note</span></div><p class="">The <code><a href="#widl-MediaEncryptedEventInit-initData">initData</a></code> attribute will be null if the media data is <em>not</em> <a href="http://www.w3.org/TR/html5/infrastructure.html#cors-same-origin">CORS-same-origin</a> or is <a href="#mixed-content">mixed content</a>.
           Applications may retrieve the Initialization Data from an alternate source.
         </p></div>
       </li>
@@ -1620,11 +1620,11 @@
         <ol>
           <li><p>Let <var title="true">media keys</var> be the <code><a href="#idl-def-MediaKeys">MediaKeys</a></code> object referenced by that atribute.</p></li>
           <li><p>Let <var title="true">cdm</var> be the CDM loaded during the <a href="#widl-MediaKeys-create-Promise-MediaKeys--DOMString-keySystem">initialization</a> of the <var title="true">media keys</var>.</p></li>
-          <li><p>If there is at least one <code><a href="#idl-def-MediaKeySession">MediaKeySession</a></code> created by the <var title="true">media keys</var> on which the <a href="#algorithms-session-close">Session Close</a> algorithm has not been run, run the following steps:</p>
-            <div class="note"><div class="note-title" aria-level="3" role="heading" id="h_note_39"><span>Note</span></div><p class="">This check ensures the <var title="true">cdm</var> has finished loading and is a prequisite for a matching key being available.</p></div>
+          <li><p>If there is at least one <code><a href="#idl-def-MediaKeySession">MediaKeySession</a></code> created by the <var title="true">media keys</var> on which the <a href="#algorithms-session-close">session close algorithm</a> has not been run, run the following steps:</p>
+            <div class="note"><div class="note-title" aria-level="3" role="heading" id="h_note_38"><span>Note</span></div><p class="">This check ensures the <var title="true">cdm</var> has finished loading and is a prequisite for a matching key being available.</p></div>
             <ol>
               <li><p>Let the <var title="true">block key ID</var> be the key ID of the current block.</p>
-                <div class="note"><div class="note-title" aria-level="3" role="heading" id="h_note_40"><span>Note</span></div><p class="">The key ID is generally specified by the container.</p></div>
+                <div class="note"><div class="note-title" aria-level="3" role="heading" id="h_note_39"><span>Note</span></div><p class="">The key ID is generally specified by the container.</p></div>
               </li>
               <li><p>Use the <var title="true">cdm</var> to execute the following steps:</p>
                 <ol>
@@ -1635,7 +1635,7 @@
                     <dd>Run the following steps:
                       <ol>
                         <li><p>Let <var title="">block key</var> be the matching key.</p>
-                          <div class="note"><div class="note-title" aria-level="3" role="heading" id="h_note_41"><span>Note</span></div><p class="">If multiple sessions contain a <em>usable</em> key for the <var title="">block key ID</var>, which key to use is <a href="#key-system">Key System</a>-dependent.</p></div>
+                          <div class="note"><div class="note-title" aria-level="3" role="heading" id="h_note_40"><span>Note</span></div><p class="">If multiple sessions contain a <em>usable</em> key for the <var title="">block key ID</var>, which key to use is <a href="#key-system">Key System</a>-dependent.</p></div>
                         </li>
                         <li><p>Use the <var title="true">cdm</var> to decrypt the block using <var title="">block key</var>.</p></li>
                         <li><p>Follow the steps for the first matching condition from the following list:</p>
@@ -1647,12 +1647,12 @@
                               <ol>
                                 <li><p>If the <code><a href="#widl-HTMLMediaElement-waitingFor">waitingFor</a></code> attribute on the media element is <code><a href="#idl-def-MediaWaitingFor.key">"key"</a></code>, set the <code><a href="#widl-HTMLMediaElement-waitingFor">waitingFor</a></code> attribute on the media element to <code><a href="#idl-def-MediaWaitingFor.none">"none"</a></code>.</p></li>
                                 <li><p>Abort these steps and process the decrypted block as normal.</p>
-                                  <div class="note"><div class="note-title" aria-level="3" role="heading" id="h_note_42"><span>Note</span></div><p class="">In other words, decode the block.</p></div>
+                                  <div class="note"><div class="note-title" aria-level="3" role="heading" id="h_note_41"><span>Note</span></div><p class="">In other words, decode the block.</p></div>
                                 </li>
                               </ol>
                             </dd>
                           </dl>
-                          <div class="note"><div class="note-title" aria-level="3" role="heading" id="h_note_43"><span>Note</span></div><p class="">Not all decryption problems (i.e. using the wrong key) will result in a decryption failure. In such cases, no error is fired here but one may be fired during decode.</p></div>
+                          <div class="note"><div class="note-title" aria-level="3" role="heading" id="h_note_42"><span>Note</span></div><p class="">Not all decryption problems (i.e. using the wrong key) will result in a decryption failure. In such cases, no error is fired here but one may be fired during decode.</p></div>
                         </li>
                       </ol>
                     </dd>
@@ -1660,7 +1660,7 @@
                     <dd>
                       <div class="issue"><div class="issue-title" aria-level="3" role="heading" id="h_issue_3"><span>Issue 3</span></div><p class=""><a href="https://www.w3.org/Bugs/Public/show_bug.cgi?id=26372">Bug 26372</a> - It is TBD whether anything should happen in this case.</p></div>
                     </dd>
-                    <div class="note"><div class="note-title" aria-level="3" role="heading" id="h_note_44"><span>Note</span></div><p class="">Otherwise, there is no key for the <var title="true">block key ID</var> in any session so continue.</p></div>
+                    <div class="note"><div class="note-title" aria-level="3" role="heading" id="h_note_43"><span>Note</span></div><p class="">Otherwise, there is no key for the <var title="true">block key ID</var> in any session so continue.</p></div>
                     </dl>
                   </li>
                 </ol>
@@ -1671,15 +1671,15 @@
       </li>
       <li>
         <p>Run the following steps:</p>
-        <div class="note"><div class="note-title" aria-level="3" role="heading" id="h_note_45"><span>Note</span></div><p class="">These steps are reached when there is no usable key for the block.</p></div>
+        <div class="note"><div class="note-title" aria-level="3" role="heading" id="h_note_44"><span>Note</span></div><p class="">These steps are reached when there is no usable key for the block.</p></div>
         <ol>
-          <li><p>Run the <a href="#algorithms-queue-waiting">Queue a "waiting" Event</a> algorithm on the media element.</p></li>
+          <li><p>Run the <a href="#algorithms-queue-waiting">queue a "waiting" event algorithm</a> on the media element.</p></li>
           <li><p>Wait for a signal to resume playback.</p></li>
         </ol>
       </li>
     </ol>
 
-    <div class="note"><div class="note-title" aria-level="3" role="heading" id="h_note_46"><span>Note</span></div><div class="">
+    <div class="note"><div class="note-title" aria-level="3" role="heading" id="h_note_45"><span>Note</span></div><div class="">
     <p>For frame-based encryption, this may be implemented as follows when the media element attempts to decode a frame as part of the <a href="http://www.w3.org/TR/html5/embedded-content-0.html#concept-media-load-resource">resource fetch algorithm</a>:</p>
     <ol>
       <li><p>Let <var title="">encrypted</var> be false.</p></li>
@@ -1726,13 +1726,13 @@
     <ol>
       <li><p>Let the <var title="true">media element</var> be the specified <code><a href="http://www.w3.org/TR/html5/embedded-content-0.html#htmlmediaelement">HTMLMediaElement</a></code> object.</p></li>
       <li><p>If the <code><a href="#widl-HTMLMediaElement-waitingFor">waitingFor</a></code> attribute on the <var title="true">media element</var> is not <code><a href="#idl-def-MediaWaitingFor.key">"key"</a></code>, abort these steps.</p></li>
-      <li><p>Attempt to resume the <a href="http://www.w3.org/TR/html5/embedded-content-0.html#concept-media-load-resource">resource fetch algorithm</a> by running the <a href="#algorithms-encrypted-block">Encrypted Block Encountered</a> algorithm.</p></li>
+      <li><p>Attempt to resume the <a href="http://www.w3.org/TR/html5/embedded-content-0.html#concept-media-load-resource">resource fetch algorithm</a> by running the <a href="#algorithms-encrypted-block">encrypted block encountered algorithm</a>.</p></li>
       <li><p>If the user agent can advance the <a href="http://www.w3.org/TR/html5/embedded-content-0.html#current-playback-position">current playback position</a> in the <a href="http://www.w3.org/TR/html5/embedded-content-0.html#direction-of-playback">direction of playback</a>, run the following steps:</p>
         <ol>
           <li><p><a href="http://www.w3.org/TR/html5/webappapis.html#queue-a-task">Queue a task</a> to <a href="http://www.w3.org/TR/html5/webappapis.html#fire-a-simple-event">fire a simple event</a> named <code><a href="http://www.w3.org/TR/html5/embedded-content-0.html#event-media-canplay">canplay</a></code> at the <var title="true">media element</var>.</p></li>
           <li><p>If the <code><a href="http://www.w3.org/TR/html5/embedded-content-0.html#dom-media-paused">paused</a></code> attribute on the <var title="true">media element</var> is false, <a href="http://www.w3.org/TR/html5/webappapis.html#queue-a-task">queue a task</a> to <a href="http://www.w3.org/TR/html5/webappapis.html#fire-a-simple-event">fire a simple event</a> named <code><a href="http://www.w3.org/TR/html5/embedded-content-0.html#dom-media-playing">playing</a></code> at the <var title="true">media element</var>.</p></li>
        </ol>
-        <p>Otherwise, the <code><a href="#widl-HTMLMediaElement-waitingFor">waitingFor</a></code> attribute on the <var title="true">media element</var> must not be <code><a href="#idl-def-MediaWaitingFor.none">"none"</a></code>.</p>
+        <p>Otherwise, the <code><a href="#widl-HTMLMediaElement-waitingFor">waitingFor</a></code> attribute on the <var title="true">media element</var> <em class="rfc2119" title="MUST NOT">MUST NOT</em> be <code><a href="#idl-def-MediaWaitingFor.none">"none"</a></code>.</p>
       </li>
     </ol>
     </section>
@@ -1741,33 +1741,33 @@
     <h4 role="heading" id="h4_htmlmediaelement-playing-the-media-resource"><span class="secno">4.5.5 </span>Playing the Media Resource Algorithm Modifications</h4>
     <p>The following steps are added to <code><a href="http://www.w3.org/TR/html5/embedded-content-0.html#dom-media-readystate">readyState</a></code> change algorithms in <a href="http://www.w3.org/TR/html5/embedded-content-0.html#playing-the-media-resource">Playing the media resource</a>:</p>
     <ul>
-      <li>If a <code><a href="http://www.w3.org/TR/html5/embedded-content-0.html#dom-media-readystate">readyState</a></code> change queues a task to fire a <code><a href="http://www.w3.org/TR/html5/embedded-content-0.html#event-media-waiting">waiting</a></code> event, the user agent must also set the <code><a href="#widl-HTMLMediaElement-waitingFor">waitingFor</a></code> attribute on the Media Element to <code><a href="#idl-def-MediaWaitingFor.data">"data"</a></code>.</li>
-      <li>If a <code><a href="http://www.w3.org/TR/html5/embedded-content-0.html#dom-media-readystate">readyState</a></code> change queues a task to fire a <code><a href="http://www.w3.org/TR/html5/embedded-content-0.html#event-media-canplay">canplay</a></code> event, the user agent must also set the <code><a href="#widl-HTMLMediaElement-waitingFor">waitingFor</a></code> attribute on the Media Element to <code><a href="#idl-def-MediaWaitingFor.none">"none"</a></code>.</li>
+      <li>If a <code><a href="http://www.w3.org/TR/html5/embedded-content-0.html#dom-media-readystate">readyState</a></code> change queues a task to fire a <code><a href="http://www.w3.org/TR/html5/embedded-content-0.html#event-media-waiting">waiting</a></code> event, the user agent <em class="rfc2119" title="MUST">MUST</em> also set the <code><a href="#widl-HTMLMediaElement-waitingFor">waitingFor</a></code> attribute on the Media Element to <code><a href="#idl-def-MediaWaitingFor.data">"data"</a></code>.</li>
+      <li>If a <code><a href="http://www.w3.org/TR/html5/embedded-content-0.html#dom-media-readystate">readyState</a></code> change queues a task to fire a <code><a href="http://www.w3.org/TR/html5/embedded-content-0.html#event-media-canplay">canplay</a></code> event, the user agent <em class="rfc2119" title="MUST">MUST</em> also set the <code><a href="#widl-HTMLMediaElement-waitingFor">waitingFor</a></code> attribute on the Media Element to <code><a href="#idl-def-MediaWaitingFor.none">"none"</a></code>.</li>
     </ul>
     </section>
     </section>
 
     <section id="media-element-restictions" class="informative" typeof="bibo:Chapter" resource="#media-element-restictions" rel="bibo:Chapter">
     <h3 role="heading" id="h3_media-element-restictions"><span class="secno">4.6 </span>Media Element Restrictions</h3><p><em>This section is non-normative.</em></p>
-    <p>Media data processed by a CDM may not be available through Javascript APIs in the usual way (for example using the CanvasRenderingContext2D drawImage() method and the AudioContext MediaElementAudioSourceNode).
-    This specification does not define conditions for such non-availability of media data, however, if media data is not available to Javascript APIs then these APIs may behave as if no media data was present at all.</p>
-    <p>Where media rendering is not performed by the UA, for example in the case of a hardware protected media pipeline, then the full set of HTML rendering capabilities, for example CSS Transforms, may not be available. One likely restriction is that
-    video media may be constrained to appear only in rectangular regions with sides parallel to the edges of the window and with normal orientation.</p>
+    <p>Media data processed by a CDM <em class="rfc2119" title="MAY">MAY</em> be unavailable through Javascript APIs in the usual way (for example using the CanvasRenderingContext2D drawImage() method and the AudioContext MediaElementAudioSourceNode).
+    This specification does not define conditions for such non-availability of media data, however, if media data is not available to Javascript APIs then these APIs <em class="rfc2119" title="MAY">MAY</em> behave as if no media data was present at all.</p>
+    <p>Where media rendering is not performed by the UA, for example in the case of a hardware protected media pipeline, then the full set of HTML rendering capabilities, for example CSS Transforms, <em class="rfc2119" title="MAY">MAY</em> be unavailable. One likely restriction is that
+    video media <em class="rfc2119" title="MAY">MAY</em> be constrained to appear only in rectangular regions with sides parallel to the edges of the window and with normal orientation.</p>
     </section>
     </section>
 
 
     <section id="common-key-systems" typeof="bibo:Chapter" resource="#common-key-systems" rel="bibo:Chapter">
     <!--OddPage--><h2 role="heading" id="h2_common-key-systems"><span class="secno">5. </span>Common Key Systems</h2>
-    <p>All user agents must support the common key systems described in this section.</p><p>
-    </p><div class="note"><div class="note-title" aria-level="1" role="heading" id="h_note_47"><span>Note</span></div><p class="">This ensures that there is a common baseline level of protection that is guaranteed to be supported in all user agents, including those that are entirely open source.
+    <p>All user agents <em class="rfc2119" title="MUST">MUST</em> support the common key systems described in this section.</p><p>
+    </p><div class="note"><div class="note-title" aria-level="1" role="heading" id="h_note_46"><span>Note</span></div><p class="">This ensures that there is a common baseline level of protection that is guaranteed to be supported in all user agents, including those that are entirely open source.
       Thus, content providers that need only basic protection can build simple applications that will work on all platforms without needing to work with any content protection providers.
     </p></div>
 
     <span id="simple-decryption-clear-key"></span> <!-- Legacy anchor name. -->
     <section id="clear-key" typeof="bibo:Chapter" resource="#clear-key" rel="bibo:Chapter">
     <h3 role="heading" id="h3_clear-key"><span class="secno">5.1 </span>Clear Key</h3>
-    <p>The "org.w3.clearkey" <a href="#key-system">Key System</a> uses plain-text clear (unencrypted) key(s) to decrypt the source.
+    <p>The <code>"org.w3.clearkey"</code> <a href="#key-system">Key System</a> uses plain-text clear (unencrypted) key(s) to decrypt the source.
     No additional client-side content protection is required.
     This Key System is described below.
     </p>
@@ -1776,10 +1776,10 @@
     <h4 role="heading" id="h4_clear-key-capabilities"><span class="secno">5.1.1 </span>Capabilities</h4>
     <p>The following describe how Clear Key supports key system-specific capabilities:</p>
     <ul>
-      <li><p>The <code><a href="#widl-HTMLMediaElement-setMediaKeys-Promise-void--MediaKeys-mediaKeys">setMediaKeys()</a></code> method: Implementations may support associating the <code><a href="#idl-def-MediaKeys">MediaKeys</a></code> object with more than one <code><a href="http://www.w3.org/TR/html5/embedded-content-0.html#htmlmediaelement">HTMLMediaElement</a></code>.</p></li>
+      <li><p>The <code><a href="#widl-HTMLMediaElement-setMediaKeys-Promise-void--MediaKeys-mediaKeys">setMediaKeys()</a></code> method: Implementations <em class="rfc2119" title="MAY">MAY</em> support associating the <code><a href="#idl-def-MediaKeys">MediaKeys</a></code> object with more than one <code><a href="http://www.w3.org/TR/html5/embedded-content-0.html#htmlmediaelement">HTMLMediaElement</a></code>.</p></li>
       <li><p>The <code><a href="#widl-MediaKeys-setServerCertificate-Promise-void--ArrayBuffer-ArrayBufferView-serverCertificate">setServerCertificate()</a></code> method: Not supported.</p></li>
       <li><p>The <code><a href="#widl-MediaKeys-isTypeSupported-IsTypeSupportedResult-DOMstring-keySystem-DOMString-initDataType-DOMString-contentType-DOMString-capability">isTypeSupported()</a></code> method: There are no supported <var title="true">capability</var> values.</p></li>
-      <li><p>The <code><a href="#idl-def-SessionType.persistent">"persistent"</a></code> <code><a href="#idl-def-SessionType">SessionType</a></code>: Implementations may support this type.</p></li>
+      <li><p>The <code><a href="#idl-def-SessionType.persistent">"persistent"</a></code> <code><a href="#idl-def-SessionType">SessionType</a></code>: Implementations <em class="rfc2119" title="MAY">MAY</em> support this type.</p></li>
     </ul>
     </section>
 
@@ -1803,8 +1803,8 @@
         </ul>
       </li>
       <li><p>The <code><a href="#widl-MediaKeySession-getUsableKeyIds-Promise-sequence-ArrayBuffer">getUsableKeyIds()</a></code> method always returns all key IDs that have been provided via <code><a href="#widl-MediaKeySession-update-Promise-void--ArrayBuffer-ArrayBufferView-response">update()</a></code>.</p></li>
-      <li><p><a href="#initialization-data">Initialization Data</a>: Implementations may support any combination of registered Initialization Data types [<cite><a class="bibref" href="#bib-EME-REGISTRY">EME-REGISTRY</a></cite>].
-        Implementations should support the "<a href="keyids-format.html">keyids</a>" type and other types appropriate for content types supported by the user agent.
+      <li><p><a href="#initialization-data">Initialization Data</a>: Implementations <em class="rfc2119" title="MAY">MAY</em> support any combination of registered Initialization Data types [<cite><a class="bibref" href="#bib-EME-REGISTRY">EME-REGISTRY</a></cite>].
+        Implementations <em class="rfc2119" title="SHOULD">SHOULD</em> support the <code><a href="keyids-format.html">"keyids"</a></code> type and other types appropriate for content types supported by the user agent.
       </p></li>
     </ul>
     </section>
@@ -1822,7 +1822,7 @@
     </dl>
 
     <p>When contained in the ArrayBuffer <code><a href="#widl-MediaKeyMessageEvent-message">message</a></code> attribute of a <code><a href="#idl-def-MediaKeyMessageEvent">MediaKeyMessageEvent</a></code> object, the JSON string is encoded in UTF-8 as specified in the Encoding specification [<cite><a class="bibref" href="#bib-ENCODING">ENCODING</a></cite>].
-      Applications may decode the contents of the ArrayBuffer to a JSON string using the <a href="http://www.w3.org/TR/encoding/#interface-textdecoder">TextDecoder interface</a> [<cite><a class="bibref" href="#bib-ENCODING">ENCODING</a></cite>].
+      Applications <em class="rfc2119" title="MAY">MAY</em> decode the contents of the ArrayBuffer to a JSON string using the <a href="http://www.w3.org/TR/encoding/#interface-textdecoder">TextDecoder interface</a> [<cite><a class="bibref" href="#bib-ENCODING">ENCODING</a></cite>].
     </p>
 
     <section id="clear-key-request-format-example" class="informative" typeof="bibo:Chapter" resource="#clear-key-request-format-example" rel="bibo:Chapter">
@@ -1857,13 +1857,13 @@
       <dd>The base64url encoding of the octet sequence containing the <a href="#decryption-key-id">key ID</a> value</dd>
     </dl>
 
-    <p>The JSON object may have an optional "type" member value, which may be any of the <code><a href="#idl-def-SessionType">SessionType</a></code> values.
+    <p>The JSON object <em class="rfc2119" title="MAY">MAY</em> have an optional "type" member value, which <em class="rfc2119" title="MUST">MUST</em> be one of the <code><a href="#idl-def-SessionType">SessionType</a></code> values.
       If not specified, the default value of <code><a href="#idl-def-SessionType.temporary">"temporary"</a></code> is used.
       The <code><a href="#widl-MediaKeySession-update-Promise-void--ArrayBuffer-ArrayBufferView-response">update()</a></code> algorithm compares this value to the <var title="true">sessionType</var>.
     </p>
 
-    <p>When passed to the <code><a href="#widl-MediaKeySession-update-Promise-void--ArrayBuffer-ArrayBufferView-response">update()</a></code> method as the ArrayBuffer <var title="true">response</var> parameter, the JSON string must be encoded in UTF-8 as specified in the Encoding specification [<cite><a class="bibref" href="#bib-ENCODING">ENCODING</a></cite>].
-      Applications may encode the JSON string using the <a href="http://www.w3.org/TR/encoding/#interface-textencoder">TextEncoder interface</a> [<cite><a class="bibref" href="#bib-ENCODING">ENCODING</a></cite>].
+    <p>When passed to the <code><a href="#widl-MediaKeySession-update-Promise-void--ArrayBuffer-ArrayBufferView-response">update()</a></code> method as the ArrayBuffer <var title="true">response</var> parameter, the JSON string <em class="rfc2119" title="MUST">MUST</em> be encoded in UTF-8 as specified in the Encoding specification [<cite><a class="bibref" href="#bib-ENCODING">ENCODING</a></cite>].
+      Applications <em class="rfc2119" title="MAY">MAY</em> encode the JSON string using the <a href="http://www.w3.org/TR/encoding/#interface-textencoder">TextEncoder interface</a> [<cite><a class="bibref" href="#bib-ENCODING">ENCODING</a></cite>].
     </p>
 
     <section id="clear-key-license-format-example" class="informative" typeof="bibo:Chapter" resource="#clear-key-license-format-example" rel="bibo:Chapter">
@@ -1885,7 +1885,7 @@
     <section id="using-base64url" class="informative" typeof="bibo:Chapter" resource="#using-base64url" rel="bibo:Chapter">
     <h4 role="heading" id="h4_using-base64url"><span class="secno">5.1.5 </span>Using base64url</h4><p><em>This section is non-normative.</em></p>
     <p>For more information on base64url and working with it, see the "Base64url Encoding" terminology definition and "Notes on implementing base64url encoding without padding" in [<cite><a class="bibref" href="#bib-JWS">JWS</a></cite>].
-      Specifically, there is no '=' padding, and the characters '-' and '_' must be used instead of '+' and '/', respectively. 
+      Specifically, there is no '=' padding, and the characters '-' and '_' <em class="rfc2119" title="MUST">MUST</em> be used instead of '+' and '/', respectively.
     </p>
     </section>
     </section>