copy current ttml-issues file into repository
authorGlenn Adams <glenn@skynav.com>
Thu, 15 Mar 2012 01:06:05 -0600
changeset 237 585fb295764c
parent 236 d99c91938a13
child 238 30436be2cc60
copy current ttml-issues file into repository
ttml10/spec/ttml-issues.html
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+<html xmlns='http://wwww.w3.org/1999/xhtml'>
+<head>
+<title>List of issues</title>
+<link rel="stylesheet" type="text/css" href="http://www.w3.org/StyleSheets/TR/base.css"/>
+</head>
+<body>
+<h1>Timed Text Markup Language (TTML) 1.0: Issues</h1>
+
+<ol>
+<li><a href='#mediaType'>Update to TTML Media Type</a></li>
+<li><a href='#tts_extent'>XML schema error for tts:extent usage</a></li>
+<li><a href='#xsd_validation'>XML Schema is too restrictive</a></li>
+</ol>
+
+<p>Note: Updated Zip archives
+for <a href='/2012/02/rnc-schema.zip'>Relax NG</a>,
+and <a href='/2012/02/xsd-schema.zip'>XML Schema</a> schemas are
+available.</p>
+
+<h2 id='mediaType'>Update to TTML Media Type</h2>
+<div class="div1">
+<h2><a id="media-type-registration" name="media-type-registration">C Media Type Registration</a></h2><p><a id="media-type-registration" name="media-type-registration"><em>This appendix is normative.</em></a></p><p><a id="media-type-registration" name="media-type-registration">This appendix registers a new MIME media type,
+"application/ttml+xml" in conformance with
+</a><a href="http://www.ietf.org/rfc/rfc4288.txt">BCP 13</a> and
+<a href="http://www.w3.org/2002/06/registering-mediatype.html">W3CRegMedia</a>.
+The information in this appendix is being submitted to the Internet
+Engineering Steering Group (IESG) for review, approval, and
+registration with the Internet Assigned Numbers Authority (IANA).</p><dl>
+<dt class="label">Type name:</dt>
+<dd><p>application</p></dd>
+<dt class="label">Subtype name:</dt>
+<dd><p>ttml+xml</p></dd>
+<dt class="label">Required parameters:</dt>
+<dd><p>None.</p></dd>
+<dt class="label">Optional parameters:</dt>
+<dd>
+<dl>
+<dt class="label">charset</dt>
+<dd><p>Same as application/xml media type, as specified in <a href="#rfc3023">[XML Media Types]</a> or its successors.</p></dd>
+<dt class="label">profile</dt>
+<dd><p>The document profile of a TTML document may be specified using
+an optional <code>profile</code> parameter, which, if specified,
+the value of which must adhere to the syntax and semantics of
+<code>ttp:profile</code> parameter defined by
+Section
+<a href="#parameter-attribute-profile"><b>6.2.8 ttp:profile</b></a>
+of the published specification.</p></dd>
+</dl>
+</dd>
+<dt class="label">Encoding considerations:</dt>
+<dd><p>Same for application/xml. See <a href="#xml-media">[XML Media]</a>, Section
+3.2.</p></dd>
+<dt class="label">Security considerations:</dt>
+<dd><p>As with other XML types and as noted in
+<a href="#xml-media">[XML Media]</a>
+Section 10, repeated expansion of maliciously constructed XML entities
+can be used to consume large amounts of memory, which may cause XML
+processors in constrained environments to fail.</p><p>In addition, because of the extensibility features for TTML and of XML
+in general, it is possible that "application/ttml+xml" may describe content
+that has security implications beyond those described here. However,
+if the processor follows only the normative semantics of the published
+specification, this content will be outside TTML namespaces and
+may be ignored. Only in the case where the processor recognizes and
+processes the additional content, or where further processing of that
+content is dispatched to other processors, would security issues
+potentially arise. And in that case, they would fall outside the
+domain of this registration document.</p></dd>
+<dt class="label">Interoperability considerations:</dt>
+<dd><p>The published specification describes processing semantics that dictate
+behavior that must be followed when dealing with, among other things,
+unrecognized elements and attributes, both in TTML namespaces and in
+other namespaces.</p><p>Because TTML is extensible, conformant "application/ttml+xml" processors must
+expect that content received is well-formed XML, but it cannot be
+guaranteed that the content is valid to a particular DTD or Schema or
+that the processor will recognize all of the elements and attributes
+in the document.</p><p></p></dd>
+<dt class="label">Published specification:</dt>
+<dd><p><a href="http://www.w3.org/TR/ttaf1-dfxp/">Timed Text Markup Language (TTML) 1.0</a>.</p></dd>
+<dt class="label">Applications that use this media type:</dt>
+<dd><p>TTML is used in the television industry for the purpose of authoring,
+        transcoding and  exchanging timed text information and for delivering captions
+        for television material repurposed for the internet.</p>
+    <p>There is partial and full support of TTML in components used by several
+        Web browsers plugins, and in a number of caption authoring tools.</p></dd>
+
+<dt class="label">Additional information:</dt>
+<dd>
+<dl>
+<dt class="label">Magic number(s):</dt>
+<dd></dd>
+<dt class="label">File extension(s):</dt>
+<dd><p>.ttml</p></dd>
+<dt class="label">Macintosh file type code(s):</dt>
+<dd><p>"TTML"</p></dd>
+<dt class="label">Fragment identifiers:</dt>
+<dd><p>For documents labeled as application/ttml+xml, the fragment
+identifier notation is intended to be used with xml:id attributes, as
+described in section 7.2.1 of
+the <a href="http://www.w3.org/TR/ttaf1-dfxp/">Timed Text Markup
+Language (TTML) 1.0</a> specification.</p></dd>
+</dl>
+</dd>
+<dt class="label">Person &amp; email address to contact for further information:</dt>
+<dd><p>Timed Text Working Group ([email protected])</p></dd>
+<dt class="label">Intended usage:</dt>
+<dd><p>COMMON</p></dd>
+<dt class="label">Restrictions on usage:</dt>
+<dd><p>None</p></dd>
+<dt class="label">Author:</dt>
+<dd><p>The published specification is a work product of the World Wide Web
+Consortium's Timed Text (TT) Working Group.</p></dd>
+<dt class="label">Change controller:</dt>
+<dd><p>The W3C has change control over this specification.</p></dd>
+</dl></div>
+
+<h2 id='tts_extent'>XML schema error for tts:extent usage</h2>
+
+<h3>B.1.2.6 Document Module</h3>
+
+<div class="exampleInner"><pre># .......................................................................
+# TT-AF 1.0 DFXP Document Module ........................................
+# .......................................................................
+
+## tt - generic top-level document element type
+TTAF.tt =
+  element tt {
+    TTAF.tt.attlist,
+    TTAF.tt.content
+  }
+
+TTAF.tt.attlist &amp;=
+  TTAF.Core.required.attrib.class,
+  TTAF.Parameter.attrib.class,
+  TTAF.extent.attrib
+
+TTAF.tt.content =
+  (TTAF.head?, TTAF.body?)
+
+# .......................................................................
+# .......................................................................
+# .......................................................................
+</pre></div>
+
+<h3>B.2.2.5 Document Module</h3>
+
+<div class="exampleInner"><pre>&lt;xs:schema targetNamespace="http://www.w3.org/ns/ttml" xml:lang="en"
+  xmlns:xs="http://www.w3.org/2001/XMLSchema"
+  xmlns:tt="http://www.w3.org/ns/ttml"
+  xmlns:ttm="http://www.w3.org/ns/ttml#metadata"
+  xmlns:ttp="http://www.w3.org/ns/ttml#parameter"
+  xmlns:tts="http://www.w3.org/ns/ttml#styling"&gt;
+  &lt;xs:import namespace="http://www.w3.org/ns/ttml#metadata"
+    schemaLocation="ttaf1-dfxp-metadata-items.xsd"/&gt;
+  &lt;xs:import namespace="http://www.w3.org/ns/ttml#parameter"
+    schemaLocation="ttaf1-dfxp-parameter-items.xsd"/&gt;
+  &lt;xs:import namespace="http://www.w3.org/ns/ttml#styling"
+    schemaLocation="ttaf1-dfxp-styling-attribs.xsd"/&gt;
+  &lt;xs:include schemaLocation="ttaf1-dfxp-core-attribs.xsd"/&gt;
+  &lt;xs:include schemaLocation="ttaf1-dfxp-timing-attribs.xsd"/&gt;
+  &lt;xs:include schemaLocation="ttaf1-dfxp-head.xsd"/&gt;
+  &lt;xs:include schemaLocation="ttaf1-dfxp-content.xsd"/&gt;
+  &lt;xs:attributeGroup name="tt.attlist"&gt;
+    &lt;xs:attributeGroup ref="tt:Core.required.attrib.class"/&gt;
+    &lt;xs:attributeGroup ref="ttp:Parameter.attrib.class"/&gt;
+    &lt;xs:attribute ref="tts:extent"/&gt;
+  &lt;/xs:attributeGroup&gt;
+  &lt;xs:complexType name="tt.eltype"&gt;
+    &lt;xs:sequence&gt;
+      &lt;xs:element ref="tt:head" minOccurs="0" maxOccurs="1"/&gt;
+      &lt;xs:element ref="tt:body" minOccurs="0" maxOccurs="1"/&gt;
+    &lt;/xs:sequence&gt;
+    &lt;xs:attributeGroup ref="tt:tt.attlist"/&gt;
+  &lt;/xs:complexType&gt;
+  &lt;xs:element name="tt" type="tt:tt.eltype"/&gt;
+&lt;/xs:schema&gt;
+</pre></div>
+
+<h2 id='xsd_validation'>XML Schema is too restrictive</h2>
+
+<h3>B.2.2.3 Core Attributes Module</h3>
+
+<pre>
+&lt;xs:schema targetNamespace="http://www.w3.org/ns/ttml" xml:lang="en"
+  xmlns:xs="http://www.w3.org/2001/XMLSchema"
+  xmlns:tt="http://www.w3.org/ns/ttml"
+  xmlns:xml="http://www.w3.org/XML/1998/namespace">
+  &lt;xs:import namespace="http://www.w3.org/XML/1998/namespace"
+    schemaLocation="xml.xsd"/>
+  &lt;xs:attributeGroup name="Core.ID.attrib.class">
+    &lt;xs:attribute ref="xml:id"/>
+  &lt;/xs:attributeGroup>
+  &lt;xs:attributeGroup name="Core.attrib.class">
+    &lt;xs:attributeGroup ref="tt:Core.ID.attrib.class"/>
+    &lt;xs:attribute ref="xml:lang"/>
+    &lt;xs:attribute ref="xml:space"/>
+    &lt;xs:anyAttribute namespace="##other"/>
+  &lt;/xs:attributeGroup>
+  &lt;xs:attributeGroup name="Core.required.attrib.class">
+    &lt;xs:attributeGroup ref="tt:Core.ID.attrib.class"/>
+    &lt;xs:attribute ref="xml:lang" use="required"/>
+    &lt;xs:attribute ref="xml:space"/>
+    &lt;xs:anyAttribute namespace="##other"/>
+  &lt;/xs:attributeGroup>
+&lt;/xs:schema>
+</pre>
+
+<h3>B.2.2.12 Parameter Items Module</h3>
+
+<p><code>profile.attlist</code>, <code>features.attlist</code>, <code>feature.attlist</code>, <code>extensions.attlist</code>, and <code>extension.attlist</code> should also contain:
+<pre>
+&lt;xs:anyAttribute namespace="##other"/>
+</pre>
+
+</body>
+</html>