[EME] Rewrite 4.2. Encrypted Block Encountered
* Wait for CDM initialization (and a usable MediaKeySession).
* Attempt to resume playback in createSession() task.
* Change error reporting in the Encrypted Block Encountered algorithm.
* Correct the error reported when decryption fails (per Bug 16857).
* Add clarity when there are multiple sessions with the same key (also in close() algorithm).
--- a/encrypted-media/encrypted-media.html Tue Nov 05 15:42:26 2013 -0800
+++ b/encrypted-media/encrypted-media.html Wed Nov 06 17:36:42 2013 -0800
@@ -56,7 +56,7 @@
<div class="head">
<p><a href="http://www.w3.org/"><img src="https://www.w3.org/Icons/w3c_home" alt="W3C" width="72" height="48"></a></p>
<h1>Encrypted Media Extensions</h1>
- <h2 id="draft-date">W3C Editor's Draft 31 October 2013</h2>
+ <h2 id="draft-date">W3C Editor's Draft 7 November 2013</h2>
<dl>
<dt>This Version:</dt>
<dd><a href="http://dvcs.w3.org/hg/html-media/raw-file/default/encrypted-media/encrypted-media.html">http://dvcs.w3.org/hg/html-media/raw-file/default/encrypted-media/encrypted-media.html</a></dd>
@@ -412,6 +412,11 @@
</ol>
</li>
<li>
+ <p>If the associated <a href="#media-element">media element(s)</a> are <a href="#waiting-for-a-key">waiting for a key</a>, <a href="http://www.w3.org/TR/html5/webappapis.html#queue-a-task">queue a task</a> to attempt to resume playback.</p>
+ <p class="non-normative">In other words, resume playback if the necessary key is provided.</p>
+ <p>The user agent may choose to skip this step if it knows resuming will fail <span class="non-normative">(i.e. no usable key was added)</span>.</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">request</var> is not null</dt>
@@ -515,8 +520,10 @@
<li><p>Abort the task.</p></li>
</ol>
</li>
- <li>If the associated <a href="#media-element">media element(s)</a> are <a href="#waiting-for-a-key">waiting for a key</a>, <a href="http://www.w3.org/TR/html5/webappapis.html#queue-a-task">queue a task</a> to attempt to resume playback.
+ <li>
+ <p>If the associated <a href="#media-element">media element(s)</a> are <a href="#waiting-for-a-key">waiting for a key</a>, <a href="http://www.w3.org/TR/html5/webappapis.html#queue-a-task">queue a task</a> to attempt to resume playback.</p>
<p class="non-normative">In other words, resume playback if the necessary key is provided.</p>
+ <p>The user agent may choose to skip this step if it knows resuming will fail <span class="non-normative">(i.e. no usable key was added)</span>.</p>
</li>
<li>
<p>Follow the steps for the first matching condition from the following list:</p>
@@ -553,6 +560,7 @@
<ol>
<li>Clear any internal state associated with the session, including all keys and licenses.</li>
</ol>
+ <p class="non-normative">Note: Keys in other sessions should be unaffected, even if they have overlapping key IDs.</p>
<p>The <dfn id="dom-sourcekeysystem"><code>keySystem</code></dfn> attribute of <code><a href="#dom-htmlsourceelement">HTMLSourceElement</a></code> specifies the <a href="#key-system">Key System</a> to be used with the <code><a href="http://www.w3.org/TR/html5/embedded-content-0.html#media-resource">media resource</a></code>.
The <a href="http://www.w3.org/TR/html5/embedded-content-0.html#concept-media-load-algorithm">resource selection algorithm</a> is modified to check the <code><a href="#dom-sourcekeysystem">keySystem</a></code> attribute after the existing <em>step 5</em> of the <em>Otherwise</em> branch of <em>step 6</em>:
@@ -603,13 +611,13 @@
<dl>
<dt>
<dfn id="dom-media_err_encrypted"><code>MEDIA_ERR_ENCRYPTED</code></dfn> (numeric value 5)</dt>
- <dd>The stream could not be played because it is encrypted and one of the following:
+ <dd>The stream could not be played because it is encrypted and one of the following is true:
<ol>
<li>The media element does not have a <code><a href="#dom-needkey">needkey</a></code> handler</li>
<li>The media element's <code><a href="#dom-keys">keys</a></code> attribute is null</li>
</ol>
<p class="non-normative">Applications that support encrypted media should provide a <code><a href="#dom-needkey">needkey</a></code> handler and/or call <code><a href="#dom-setmediakeys">setMediaKeys()</a></code> no later than when <a href="http://www.w3.org/TR/html5/embedded-content-0.html#media-data">media data</a> is provided.</p>
- <p class="non-normative">If the user agent does not support decryption of this <a href="http://www.w3.org/TR/html5/embedded-content-0.html#media-data">media data</a>, it should report the same error it would for any other unsupported media data (e.g. <code>MEDIA_ERR_SRC_NOT_SUPPORTED</code>).</p>
+ <p class="non-normative">If the user agent does not support decryption of this <a href="http://www.w3.org/TR/html5/embedded-content-0.html#media-data">media data</a>, it should report the same error it would for any other unsupported media data (e.g. <code><a href="http://www.w3.org/TR/html5/embedded-content-0.html#dom-mediaerror-media_err_src_not_supported">MEDIA_ERR_SRC_NOT_SUPPORTED</a></code>).</p>
</dd>
</dl>
@@ -847,7 +855,7 @@
<p class="non-normative">Note that <code title="dom-media-readyState"><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 is merely informative.</p>
</dd>
<dt>Otherwise</dt>
- <dd>Abort media element's <a href="http://www.w3.org/TR/html5/embedded-content-0.html#concept-media-load-resource">resource fetch algorithm</a>, run the steps to report a <code><a href="#dom-media_err_encrypted">MEDIA_ERR_ENCRYPTED</a></code> error, and abort these steps.</dd>
+ <dd>Abort the media element's <a href="http://www.w3.org/TR/html5/embedded-content-0.html#concept-media-load-resource">resource fetch algorithm</a>, run the steps to report a <code><a href="#dom-media_err_encrypted">MEDIA_ERR_ENCRYPTED</a></code> error, and abort these steps.</dd>
</dl>
</li>
@@ -858,47 +866,79 @@
<p>The following steps are run when the <a href="#media-element">media element</a> encounters a block <span class="non-normative">(i.e. frame)</span> of encrypted <a href="http://www.w3.org/TR/html5/embedded-content-0.html#media-data">media data</a> during 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="">cdm</var> be null.</p></li>
- <li><p>Let <var title="">block key</var> be null.</p></li>
- <li>
-<p>Determine whether there is an active <a href="#cdm">CDM</a> by following the steps for the first matching condition from the following list:</p>
- <dl class="switch">
- <dt>If the media element's <code><a href="#dom-keys">keys</a></code> attribute is not null</dt>
- <dd>Let <var title="true">cdm</var> be the <var title="true">cdm</var> loaded in the <a href="#dom-media-keys-constructor"><code>MediaKeys</code> constructor</a>.</dd>
- <dt>Otherwise</dt>
- <dd>Jump to the <i>Key Presence</i> step below.</dd>
- </dl>
- </li>
<li>
-<p>Use <var title="true">cdm</var> to select the key:</p>
- <ol>
- <li><p>Let <var title="">block key ID</var> be be the key ID for the current block.</p></li>
- <li><p>If <var title="true">cdm</var> has a key cached for <var title="">block key ID</var>, let <var title="">block key</var> be the matching cached key.</p></li>
- </ol>
- </li>
- <li>
-<p><i>Key Presence</i>: Handle the presence of a key by following the steps for the first matching condition from the following list:</p>
- <dl class="switch">
- <dt>If <var title="">cdm</var> is not null and <var title="">block key</var> is not null.</dt>
- <dd>Use <var title="true">cdm</var> to Decrypt the block using <var title="">block key</var> by following the steps for the first matching condition from the following list:
- <dl class="switch">
- <dt>If decryption fails</dt>
- <dd>Abort media element's <a href="http://www.w3.org/TR/html5/embedded-content-0.html#concept-media-load-resource">resource fetch algorithm</a> and run the steps to report a <code><a href="#dom-media_err_encrypted">MEDIA_ERR_ENCRYPTED</a></code> error.</dd>
- <dt>Otherwise</dt>
- <dd>Continue.</dd>
- </dl>
- <p class="non-normative">Note: 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>
+<p>Follow the steps for the first matching condition from the following list:</p>
+ <dl class="switch">
+ <dt>If the media element's <code><a href="#dom-keys">keys</a></code> attribute is not null:</dt>
+ <dd>Run the following steps:
+ <ol>
+ <li><p>Let <var title="true">cdm</var> be the <var title="true">cdm</var> loaded in the <a href="#dom-media-keys-constructor"><code>MediaKeys</code> constructor</a>.</p></li>
+ <li>
+<p>If <var title="true">cdm</var> does not have at least one <code><a href="#dom-mediakeysession">MediaKeySession</a></code> in the <code><a href="#dom-statepending">PENDING</a></code> or <code><a href="#dom-stateready">READY</a></code> state, abort these steps and wait for a signal to resume playback.</p>
+ <p class="non-normative">This check ensures the <var title="true">cdm</var> has finished loading and is a prequisite for a matching key being available.</p>
+ <p class="non-normative">If playback stops because the stream cannot be decrypted when the <a href="#media-element">media element</a> is <code><a href="http://www.w3.org/TR/html5/embedded-content-0.html#potentially-playing">potentially playing</a></code>, the media element is said to be <a href="#waiting-for-a-key">waiting for a key</a>.</p>
+ </li>
+ <li><p>Let <var title="true">block key ID</var> be be the key ID for the current block.</p></li>
+ <li>
+<p>Use <var title="true">cdm</var> to decrypt the block by following the steps for the first matching condition from the following list:</p>
+ <dl class="switch">
+ <dt>If any session has a usable key for <var title="">block key ID</var>
+</dt>
+ <dd>Run the following steps:
+ <ol>
+ <li>
+<p>Let <var title="">block key</var> be the matching key.</p>
+ <p class="non-normative">Note: If multiple sessions contain a <em>usable</em> key for <var title="">block key ID</var>, which session is used is <a href="#key-system">Key System</a>-dependent.</p>
+ </li>
+ <li>
+<p>Use <var title="true">cdm</var> to decrypt the block using <var title="">block key</var> by following the steps for the first matching condition from the following list:</p>
+ <dl class="switch">
+ <dt>If decryption fails</dt>
+ <dd>Abort the media element's <a href="http://www.w3.org/TR/html5/embedded-content-0.html#concept-media-load-resource">resource fetch algorithm</a>, run the steps to report a <code><a href="http://www.w3.org/TR/html5/embedded-content-0.html#dom-mediaerror-media_err_decode">MEDIA_ERR_DECODE</a></code> error, and abort these steps.</dd>
+ <dt>Otherwise</dt>
+ <dd>Abort these steps and process the decrypted block as normal. <span class="non-normative">(Decode the block.)</span>
+</dd>
+ </dl>
+ <p class="non-normative">Note: 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>
+ </li>
+ </ol>
+ </dd>
+ <dt>If any session has an unusable key for <var title="">block key ID</var>
+</dt>
+ <dd>Run the following steps:
+ <ol>
+ <li><p>Let <var title="">session</var> be the <code><a href="#dom-mediakeysession">MediaKeySession</a></code> object for the session with an unusable key.</p></li>
+ <li>
+<p>Create a new <code><a href="#dom-mediakeyerror">MediaKeyError</a></code> object with the following attributes:</p>
+ <ul style="list-style-type:none"><li>
+ <code><a href="#dom-code">code</a></code> = the appropriate <code><a href="#dom-mediakeyerror">MediaKeyError</a></code> code<br>
+ <code><a href="#dom-systemcode">systemCode</a></code> = a Key System-specific value, if provided, and 0 otherwise
+ </li></ul>
+ </li>
+ <li><p>Set <var title="">session</var>'s <code><a href="#dom-error">error</a></code> attribute to the error object created in the previous step.</p></li>
+ <li><p>Let the state of <var title="">session</var> be <code><a href="#dom-stateerror">ERROR</a></code>.</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-eventerror">error</a></code> at <var title="">session</var>.</p></li>
+ <li><p>Abort these steps and wait for a signal to resume playback.</p></li>
+ </ol>
+ <p class="non-normative">If playback stops because the stream cannot be decrypted when the <a href="#media-element">media element</a> is <code><a href="http://www.w3.org/TR/html5/embedded-content-0.html#potentially-playing">potentially playing</a></code>, the media element is said to be <a href="#waiting-for-a-key">waiting for a key</a>.</p>
+ </dd>
+ <dt>Otherwise <span class="non-normative">(there is no key for <var title="true">block key ID</var> in any session)</span>
+</dt>
+ <dd>Abort these steps and wait for a signal to resume playback.
+ <p class="non-normative">If playback stops because the stream cannot be decrypted when the <a href="#media-element">media element</a> is <code><a href="http://www.w3.org/TR/html5/embedded-content-0.html#potentially-playing">potentially playing</a></code>, the media element is said to be <a href="#waiting-for-a-key">waiting for a key</a>.</p>
+ </dd>
+ </dl>
+ </li>
+ </ol>
</dd>
<dt>If there is an event handler for <code><a href="#dom-needkey">needkey</a></code>
</dt>
<dd>
- <p>Take no action.</p>
- <p class="non-normative">The <a href="#media-element">media element</a> is said to be <code><a href="http://www.w3.org/TR/html5/embedded-content-0.html#potentially-playing">potentially playing</a></code>
- unless playback stops because the stream cannot be decrypted, in which case the <a href="#media-element">media element</a> is said to be <a href="#waiting-for-a-key">waiting for a key</a>.
- </p>
+ <p>Abort these steps and wait for a signal to resume playback.</p>
+ <p class="non-normative">If playback stops because the stream cannot be decrypted when the <a href="#media-element">media element</a> is <code><a href="http://www.w3.org/TR/html5/embedded-content-0.html#potentially-playing">potentially playing</a></code>, the media element is said to be <a href="#waiting-for-a-key">waiting for a key</a>.</p>
</dd>
<dt>Otherwise</dt>
- <dd>Abort media element's <a href="http://www.w3.org/TR/html5/embedded-content-0.html#concept-media-load-resource">resource fetch algorithm</a> and run the steps to report a <code><a href="#dom-media_err_encrypted">MEDIA_ERR_ENCRYPTED</a></code> error.</dd>
+ <dd>Abort the media element's <a href="http://www.w3.org/TR/html5/embedded-content-0.html#concept-media-load-resource">resource fetch algorithm</a> and run the steps to report a <code><a href="#dom-media_err_encrypted">MEDIA_ERR_ENCRYPTED</a></code> error.</dd>
</dl>
</li>
</ol>
--- a/encrypted-media/encrypted-media.xml Tue Nov 05 15:42:26 2013 -0800
+++ b/encrypted-media/encrypted-media.xml Wed Nov 06 17:36:42 2013 -0800
@@ -55,7 +55,7 @@
<div class="head">
<p><a href="http://www.w3.org/"><img src="https://www.w3.org/Icons/w3c_home" alt="W3C" width="72" height="48" /></a></p>
<h1>Encrypted Media Extensions</h1>
- <h2 id="draft-date">W3C Editor's Draft 31 October 2013</h2>
+ <h2 id="draft-date">W3C Editor's Draft 7 November 2013</h2>
<dl>
<dt>This Version:</dt>
<dd><a href="http://dvcs.w3.org/hg/html-media/raw-file/default/encrypted-media/encrypted-media.html">http://dvcs.w3.org/hg/html-media/raw-file/default/encrypted-media/encrypted-media.html</a></dd>
@@ -399,6 +399,11 @@
<li><p>Abort the task.</p></li>
</ol>
</li>
+ <li>
+ <p>If the associated <a href="#media-element">media element(s)</a> are <a href="#waiting-for-a-key">waiting for a key</a>, <queue-a-task/> to attempt to resume playback.</p>
+ <p class="non-normative">In other words, resume playback if the necessary key is provided.</p>
+ <p>The user agent may choose to skip this step if it knows resuming will fail <span class="non-normative">(i.e. no usable key was added)</span>.</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">request</var> is not null</dt>
@@ -497,8 +502,10 @@
<li><p>Abort the task.</p></li>
</ol>
</li>
- <li>If the associated <a href="#media-element">media element(s)</a> are <a href="#waiting-for-a-key">waiting for a key</a>, <queue-a-task/> to attempt to resume playback.
+ <li>
+ <p>If the associated <a href="#media-element">media element(s)</a> are <a href="#waiting-for-a-key">waiting for a key</a>, <queue-a-task/> to attempt to resume playback.</p>
<p class="non-normative">In other words, resume playback if the necessary key is provided.</p>
+ <p>The user agent may choose to skip this step if it knows resuming will fail <span class="non-normative">(i.e. no usable key was added)</span>.</p>
</li>
<li><p>Follow the steps for the first matching condition from the following list:</p>
<dl class="switch">
@@ -534,6 +541,7 @@
<ol>
<li>Clear any internal state associated with the session, including all keys and licenses.</li>
</ol>
+ <p class="non-normative">Note: Keys in other sessions should be unaffected, even if they have overlapping key IDs.</p>
<p>The <codedfn prefix="source">keySystem</codedfn> attribute of <coderef>HTMLSourceElement</coderef> specifies the <a href="#key-system">Key System</a> to be used with the <videoref name="media-resource">media resource</videoref>.
The <resource-selection-algorithm/> is modified to check the <coderef prefix="source">keySystem</coderef> attribute after the existing <em>step 5</em> of the <em>Otherwise</em> branch of <em>step 6</em>:
@@ -576,13 +584,13 @@
<p>The <codedfn prefix="mediaerror">code</codedfn> attribute of a <coderef>MediaError</coderef> may additionally return the following:</p>
<dl>
<dt><codedfn>MEDIA_ERR_ENCRYPTED</codedfn> (numeric value 5)</dt>
- <dd>The stream could not be played because it is encrypted and one of the following:
+ <dd>The stream could not be played because it is encrypted and one of the following is true:
<ol>
<li>The media element does not have a <coderef>needkey</coderef> handler</li>
<li>The media element's <coderef>keys</coderef> attribute is null</li>
</ol>
<p class="non-normative">Applications that support encrypted media should provide a <coderef>needkey</coderef> handler and/or call <methodref>setMediaKeys</methodref> no later than when <videoanchor name="media-data">media data</videoanchor> is provided.</p>
- <p class="non-normative">If the user agent does not support decryption of this <videoanchor name="media-data">media data</videoanchor>, it should report the same error it would for any other unsupported media data (e.g. <code>MEDIA_ERR_SRC_NOT_SUPPORTED</code>).</p>
+ <p class="non-normative">If the user agent does not support decryption of this <videoanchor name="media-data">media data</videoanchor>, it should report the same error it would for any other unsupported media data (e.g. <videoref name="dom-mediaerror-media_err_src_not_supported">MEDIA_ERR_SRC_NOT_SUPPORTED</videoref>).</p>
</dd>
</dl>
@@ -801,7 +809,7 @@
<p class="non-normative">Note that <readystate/> is <em>not</em> changed and no algorithms are aborted. This event is merely informative.</p>
</dd>
<dt>Otherwise</dt>
- <dd>Abort media element's <resource-fetch-algorithm/>, run the steps to report a <coderef>MEDIA_ERR_ENCRYPTED</coderef> error, and abort these steps.</dd>
+ <dd>Abort the media element's <resource-fetch-algorithm/>, run the steps to report a <coderef>MEDIA_ERR_ENCRYPTED</coderef> error, and abort these steps.</dd>
</dl>
</li>
@@ -812,43 +820,68 @@
<p>The following steps are run when the <a href="#media-element">media element</a> encounters a block <span class="non-normative">(i.e. frame)</span> of encrypted <videoanchor name="media-data">media data</videoanchor> during the <resource-fetch-algorithm/>:</p>
<ol>
- <li><p>Let <var title="">cdm</var> be null.</p></li>
- <li><p>Let <var title="">block key</var> be null.</p></li>
- <li><p>Determine whether there is an active <a href="#cdm">CDM</a> by following the steps for the first matching condition from the following list:</p>
- <dl class="switch">
- <dt>If the media element's <coderef>keys</coderef> attribute is not null</dt>
- <dd>Let <var title="true">cdm</var> be the <var title="true">cdm</var> loaded in the <a href="#dom-media-keys-constructor"><code>MediaKeys</code> constructor</a>.</dd>
- <dt>Otherwise</dt>
- <dd>Jump to the <i>Key Presence</i> step below.</dd>
- </dl>
- </li>
- <li><p>Use <var title="true">cdm</var> to select the key:</p>
- <ol>
- <li><p>Let <var title="">block key ID</var> be be the key ID for the current block.</p></li>
- <li><p>If <var title="true">cdm</var> has a key cached for <var title="">block key ID</var>, let <var title="">block key</var> be the matching cached key.</p></li>
- </ol>
- </li>
- <li><p><i>Key Presence</i>: Handle the presence of a key by following the steps for the first matching condition from the following list:</p>
- <dl class="switch">
- <dt>If <var title="">cdm</var> is not null and <var title="">block key</var> is not null.</dt>
- <dd>Use <var title="true">cdm</var> to Decrypt the block using <var title="">block key</var> by following the steps for the first matching condition from the following list:
- <dl class="switch">
- <dt>If decryption fails</dt>
- <dd>Abort media element's <resource-fetch-algorithm/> and run the steps to report a <coderef>MEDIA_ERR_ENCRYPTED</coderef> error.</dd>
- <dt>Otherwise</dt>
- <dd>Continue.</dd>
- </dl>
- <p class="non-normative">Note: 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>
+ <li><p>Follow the steps for the first matching condition from the following list:</p>
+ <dl class="switch">
+ <dt>If the media element's <coderef>keys</coderef> attribute is not null:</dt>
+ <dd>Run the following steps:
+ <ol>
+ <li><p>Let <var title="true">cdm</var> be the <var title="true">cdm</var> loaded in the <a href="#dom-media-keys-constructor"><code>MediaKeys</code> constructor</a>.</p></li>
+ <li><p>If <var title="true">cdm</var> does not have at least one <coderef>MediaKeySession</coderef> in the <coderef prefix="state">PENDING</coderef> or <coderef prefix="state">READY</coderef> state, abort these steps and wait for a signal to resume playback.</p>
+ <p class="non-normative">This check ensures the <var title="true">cdm</var> has finished loading and is a prequisite for a matching key being available.</p>
+ <p class="non-normative">If playback stops because the stream cannot be decrypted when the <a href="#media-element">media element</a> is <videoref name="potentially-playing">potentially playing</videoref>, the media element is said to be <a href="#waiting-for-a-key">waiting for a key</a>.</p>
+ </li>
+ <li><p>Let <var title="true">block key ID</var> be be the key ID for the current block.</p></li>
+ <li><p>Use <var title="true">cdm</var> to decrypt the block by following the steps for the first matching condition from the following list:</p>
+ <dl class="switch">
+ <dt>If any session has a usable key for <var title="">block key ID</var></dt>
+ <dd>Run the following steps:
+ <ol>
+ <li><p>Let <var title="">block key</var> be the matching key.</p>
+ <p class="non-normative">Note: If multiple sessions contain a <em>usable</em> key for <var title="">block key ID</var>, which session is used is <a href="#key-system">Key System</a>-dependent.</p>
+ </li>
+ <li><p>Use <var title="true">cdm</var> to decrypt the block using <var title="">block key</var> by following the steps for the first matching condition from the following list:</p>
+ <dl class="switch">
+ <dt>If decryption fails</dt>
+ <dd>Abort the media element's <resource-fetch-algorithm/>, run the steps to report a <videoref name="dom-mediaerror-media_err_decode">MEDIA_ERR_DECODE</videoref> error, and abort these steps.</dd>
+ <dt>Otherwise</dt>
+ <dd>Abort these steps and process the decrypted block as normal. <span class="non-normative">(Decode the block.)</span></dd>
+ </dl>
+ <p class="non-normative">Note: 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>
+ </li>
+ </ol>
+ </dd>
+ <dt>If any session has an unusable key for <var title="">block key ID</var></dt>
+ <dd>Run the following steps:
+ <ol>
+ <li><p>Let <var title="">session</var> be the <coderef>MediaKeySession</coderef> object for the session with an unusable key.</p></li>
+ <li><p>Create a new <coderef>MediaKeyError</coderef> object with the following attributes:</p>
+ <ul style="list-style-type:none"><li>
+ <coderef>code</coderef> = the appropriate <coderef>MediaKeyError</coderef> code<br></br>
+ <coderef>systemCode</coderef> = a Key System-specific value, if provided, and 0 otherwise
+ </li></ul>
+ </li>
+ <li><p>Set <var title="">session</var>'s <coderef>error</coderef> attribute to the error object created in the previous step.</p></li>
+ <li><p>Let the state of <var title="">session</var> be <coderef prefix="state">ERROR</coderef>.</p></li>
+ <li><p><queue-a-task/> to <fire-a-simple-event/> named <coderef prefix="event">error</coderef> at <var title="">session</var>.</p></li>
+ <li><p>Abort these steps and wait for a signal to resume playback.</p></li>
+ </ol>
+ <p class="non-normative">If playback stops because the stream cannot be decrypted when the <a href="#media-element">media element</a> is <videoref name="potentially-playing">potentially playing</videoref>, the media element is said to be <a href="#waiting-for-a-key">waiting for a key</a>.</p>
+ </dd>
+ <dt>Otherwise <span class="non-normative">(there is no key for <var title="true">block key ID</var> in any session)</span></dt>
+ <dd>Abort these steps and wait for a signal to resume playback.
+ <p class="non-normative">If playback stops because the stream cannot be decrypted when the <a href="#media-element">media element</a> is <videoref name="potentially-playing">potentially playing</videoref>, the media element is said to be <a href="#waiting-for-a-key">waiting for a key</a>.</p>
+ </dd>
+ </dl>
+ </li>
+ </ol>
</dd>
<dt>If there is an event handler for <coderef>needkey</coderef></dt>
<dd>
- <p>Take no action.</p>
- <p class="non-normative">The <a href="#media-element">media element</a> is said to be <videoref name="potentially-playing">potentially playing</videoref>
- unless playback stops because the stream cannot be decrypted, in which case the <a href="#media-element">media element</a> is said to be <a href="#waiting-for-a-key">waiting for a key</a>.
- </p>
+ <p>Abort these steps and wait for a signal to resume playback.</p>
+ <p class="non-normative">If playback stops because the stream cannot be decrypted when the <a href="#media-element">media element</a> is <videoref name="potentially-playing">potentially playing</videoref>, the media element is said to be <a href="#waiting-for-a-key">waiting for a key</a>.</p>
</dd>
<dt>Otherwise</dt>
- <dd>Abort media element's <resource-fetch-algorithm/> and run the steps to report a <coderef>MEDIA_ERR_ENCRYPTED</coderef> error.</dd>
+ <dd>Abort the media element's <resource-fetch-algorithm/> and run the steps to report a <coderef>MEDIA_ERR_ENCRYPTED</coderef> error.</dd>
</dl>
</li>
</ol>