[ttml11] Manually update from TTML10.
authorGlenn Adams <glenn@skynav.com>
Tue, 09 Jul 2013 14:39:28 -0600
changeset 428 9e3f6c1d5cd9
parent 427 44338eddeba5
child 429 f2ae6b048445
[ttml11] Manually update from TTML10.
ttml11/spec/ackcurrent.xml
ttml11/spec/acknowledgements-current.txt
ttml11/spec/acknowledgements-old.txt
ttml11/spec/acknowledgements.xml
ttml11/spec/ackold.xml
ttml11/spec/build.xml
ttml11/spec/changelog.xml
ttml11/spec/diffmk.jar
ttml11/spec/diffspec.xsl
ttml11/spec/editlist.txt
ttml11/spec/entities.dtd
ttml11/spec/entitiescr.dtd
ttml11/spec/entitieswd.dtd
ttml11/spec/examples/ex1-p-0.xml
ttml11/spec/examples/ex1-x-0.xml
ttml11/spec/examples/ex1-x-1.xml
ttml11/spec/examples/ex1-x-2.xml
ttml11/spec/examples/ex1.xml
ttml11/spec/examples/ex2-paint-on.xml
ttml11/spec/examples/ex2-pop-on.xml
ttml11/spec/examples/ex2-roll-up.xml
ttml11/spec/examples/ex3-all-elements.xml
ttml11/spec/examples/ex3-all-styles.xml
ttml11/spec/generate-acknowledgements.xsl
ttml11/spec/profiles/dfxp-full.xml
ttml11/spec/profiles/dfxp-presentation.xml
ttml11/spec/profiles/dfxp-transformation.xml
ttml11/spec/rnc/schema.zip
ttml11/spec/rnc/ttml11-datatypes.rnc
ttml11/spec/rnc/ttml11-metadata.rnc
ttml11/spec/rnc/ttml11.rnc
ttml11/spec/scm/.cvsignore
ttml11/spec/scm/adi.scm
ttml11/spec/scm/compile.scm
ttml11/spec/scm/dfxp.pkg
ttml11/spec/scm/dtf.scm
ttml11/spec/scm/fox.scm
ttml11/spec/scm/load.scm
ttml11/spec/scm/rxi.scm
ttml11/spec/scm/test.xml
ttml11/spec/scm/tir.scm
ttml11/spec/ttml-changes.html
ttml11/spec/ttml-issues.html
ttml11/spec/ttml11.xml
ttml11/spec/xmlspec-ttml11.dtd
ttml11/spec/xmlspec-ttml11.xsl
ttml11/spec/xmlspec.dtd
ttml11/spec/xmlspec.xsl
ttml11/spec/xsd/schema.zip
ttml11/spec/xsd/ttml11-animation.xsd
ttml11/spec/xsd/ttml11-bindings.xjb
ttml11/spec/xsd/ttml11-content.xsd
ttml11/spec/xsd/ttml11-core-attribs.xsd
ttml11/spec/xsd/ttml11-datatypes.xsd
ttml11/spec/xsd/ttml11-document.xsd
ttml11/spec/xsd/ttml11-head.xsd
ttml11/spec/xsd/ttml11-layout.xsd
ttml11/spec/xsd/ttml11-metadata-attribs.xsd
ttml11/spec/xsd/ttml11-metadata-items.xsd
ttml11/spec/xsd/ttml11-metadata.xsd
ttml11/spec/xsd/ttml11-parameter-attribs.xsd
ttml11/spec/xsd/ttml11-parameter-items.xsd
ttml11/spec/xsd/ttml11-parameters.xsd
ttml11/spec/xsd/ttml11-styling-attribs.xsd
ttml11/spec/xsd/ttml11-styling.xsd
ttml11/spec/xsd/ttml11-timing-attribs.xsd
ttml11/spec/xsd/ttml11.xsd
ttml11/spec/xsd/xml.xsd
--- a/ttml11/spec/acknowledgements-current.txt	Tue Jul 09 11:28:27 2013 -0600
+++ b/ttml11/spec/acknowledgements-current.txt	Tue Jul 09 14:39:28 2013 -0600
@@ -1,1 +1,43 @@
-Glenn Adams (Samsung Electronics Co., Ltd.), John Birch (Invited expert), Kees Blom (CWI), Dick Bulterman (CWI), Frans de Jong (Invited expert), Mike Dolan (W3C Invited Experts), Geoff Freed (WGBH National Center for Accessible Media), Sean Hayes (Microsoft Corporation), David Kirby (British Broadcasting Corporation), Andrew Kirkpatrick (Adobe Systems Inc.), Philippe Le Hégaret (W3C/MIT), Matthew May (Adobe Systems Inc.), Soohong Daniel Park (Samsung Electronics Co., Ltd.), Brad Botkin, Donald Evans, Markus Gylling, Markku Hakkinen, Erik Hodge, Masahiko Kaneko, George Kerscher, Chris Lilley, Thierry Michel, Patrick Schmitz, David Singer.
+Glenn Adams,
+Thomas Bause-Mason,
+John Birch,
+Kees Blom,
+Bert Bos,
+Brad Botkin,
+Dick Bulterman,
+Frans de Jong,
+Mike Dolan,
+Martin D&uuml;rst,
+Donald Evans,
+Geoff Freed,
+Al Gilman,
+Giles Godart-Brown,
+Markus Gylling,
+Markku Hakkinen,
+Sean Hayes,
+Erik Hodge,
+Philipp Hoschka,
+Suzi Hyun,
+Michael Jordan,
+Masahiko Kaneko,
+Courtney Kennedy,
+George Kerscher,
+David Kirby,
+Andrew Kirkpatrick,
+Philippe Le Hégaret,
+Chris Lilley,
+Pierre-Anthony Lemieux,
+Jason Livingston,
+Monica Martin,
+Thierry Michel,
+Matthew May,
+Frank Olivier,
+Soohong Daniel Park,
+Silvia Pfeiffer,
+Brian Raymor,
+David Ronca,
+Patrick Schmitz,
+David Singer,
+Craig Smithpeters,
+Andreas Tai,
+and Mohamed Zergaoui.
--- a/ttml11/spec/acknowledgements.xml	Tue Jul 09 11:28:27 2013 -0600
+++ b/ttml11/spec/acknowledgements.xml	Tue Jul 09 14:39:28 2013 -0600
@@ -1,32 +1,16 @@
 <?xml version="1.0" encoding="utf-8"?>
 <inform-div1 id="acknowledgments">
 <head>Acknowledgments</head>
-<p>The editor acknowledges the members of the Timed Text Working
+<p>The editor acknowledges the current and former members of the Timed Text Working
 Group, the members of other W3C Working Groups, and industry experts
 in other forums who have contributed directly or indirectly to the
-process or content of creating this document.</p>
-<p>The current and former members of the Timed Text Working Group are:
-&acknowledgements-current;
-</p>
+process or content of this document as follows:</p>
+<p>&acknowledgements-current;</p>
 <p>The editor wishes to especially acknowledge the following contributions
 by members: Micheal Dolan (SMPTE time codes, streaming; SMPTE liaison), David
 Kirby (introductory example document; SMPTE time codes, descriptive metadata; EBU/AAF liaison), Geoff Freed (styling
 and example images of style properties), Sean Hayes (advanced profile
 concepts, including applicative timing), Eric Hodge (timing),
 Thierry Michel (metadata), and Dave Singer (animation, scrolling).</p>
-<p>The Timed Text Working Group has benefited in its work from the
-participation and contributions of a number of people not currently
-members of the Working Group, including in particular those named
-below. Affiliations given are those current at the time of their work
-with the WG.</p>
-<p>
-John Birch, Screen Subtitling Systems;
-Bert Bos, W3C (chair, CSS WG);
-Martin D&uuml;rst, W3C (leader, I18N Activity);
-Al Gilman (chair, WAI Protocol and Formats WG);
-Philipp Hoschka, W3C (leader, Interaction Domain);
-Chris Lilley, W3C (chair, SVG WG).
-</p>
-<p>The editor wishes to especially acknowledge the following contributions
-by non-members: John Birch (dynamic flow).</p>
+<p>The Working Group dedicates this specification to our colleague David Kirby.</p>
 </inform-div1>
--- a/ttml11/spec/build.xml	Tue Jul 09 11:28:27 2013 -0600
+++ b/ttml11/spec/build.xml	Tue Jul 09 14:39:28 2013 -0600
@@ -2,33 +2,32 @@
 <!-- Apache Ant script to build spec.
      Philippe Le Hegaret, W3C -->
       
-<project name="TimedText" default="main" basedir=".">
+<project name="TimedText" default="generate" basedir=".">
     <path id="saxon8.classpath">
         <pathelement location="saxon8/saxon8.jar"/>
     </path>
-    <property name="htmlOutputDir" value="./"/>
+    <property name="html.dir" value="${basedir}"/>
+    <property name="html.name" value="ttml11.html"/>
     <property name="stylesheet" value="xmlspec-ttml11.xsl"/>
     <property name="glossary" value="extract-glist.xsl"/>
-	<property name="generateBPlist" value="generateBPlist.xsl"/>
-    <property name="diffformat" value="diffspec.xsl"/>
+    <property name="generateBPlist" value="generateBPlist.xsl"/>
     <property name="last-public-draft" value="20070706"/>
     
     <property name="jing.jar" value="${basedir}/jing/jing.jar"/>
     <property name="rnc.dir" value="${basedir}/rnc"/>
     <property name="rnc.schema" value="${rnc.dir}/ttml11.rnc"/>
+    <property name="xsd.dir" value="${basedir}/xsd"/>
+    <property name="xsd.schema" value="${xsd.dir}/ttml11.xsd"/>
     <property name="profiles.dir" value="${basedir}/profiles"/>
+    <property name="examples.dir" value="${basedir}/examples"/>
 
     <patternset id="escapable">
       <include name="examples/*.xml"/>
-      <include name="rnc/*.rnc"/>
-      <include name="xsd/*.xsd"/>
       <include name="profiles/*.xml"/>
     </patternset>
 
     <patternset id="escaped">
       <include name="examples/*.esc"/>
-      <include name="rnc/*.esc"/>
-      <include name="xsd/*.esc"/>
       <include name="profiles/*.esc"/>
     </patternset>
 
@@ -41,7 +40,7 @@
     </target>
 
     <target name="clean" depends="clean-escapes">
-        <delete quiet="true" file="ttml11.html"/>
+        <delete quiet="true" file="${html.name}"/>
     </target>
 
     <target name="validate-schema-rnc" description="Validates DFXP's RNC Schema.">
@@ -51,6 +50,43 @@
         </java>
     </target>
 
+    <target name="generate-schema-archive-rnc" description="Generate DFXP's RNC Schema archive." depends="validate-schema-rnc">
+        <zip destfile="${rnc.dir}/schema.zip">
+            <fileset dir="${rnc.dir}">
+                <include name="*.rnc"/>
+            </fileset>
+        </zip>
+    </target>
+
+    <target name="create-xsd-bindings" description="Create JAXB Bindings for DFXP's XSD Schema.">
+        <exec executable="xjc" dir="xsd">
+          <arg value="-quiet"/>
+          <arg value="-b"/>
+          <arg value="ttml11-bindings.xjb"/>
+          <arg value="ttml11.xsd"/>
+        </exec>
+    </target>
+
+    <target name="delete-xsd-bindings" description="Delete JAXB Bindings for DFXP's XSD Schema.">
+        <delete includeemptydirs="true">
+          <fileset dir="xsd/org"/>
+        </delete>
+    </target>
+
+    <target name="validate-schema-xsd" description="Validates DFXP's XSD Schema using JAXB tool set." depends="create-xsd-bindings, delete-xsd-bindings"/>
+
+    <target name="generate-schema-archive-xsd" description="Generate DFXP's XSD Schema archive." depends="validate-schema-xsd">
+        <zip destfile="${xsd.dir}/schema.zip">
+            <fileset dir="${xsd.dir}">
+                <include name="*.xsd"/>
+            </fileset>
+        </zip>
+    </target>
+
+    <target name="validate-schemas" description="Validate DFXP schemas" depends="validate-schema-rnc, validate-schema-xsd"/>
+
+    <target name="generate-schema-archives" description="Generate DFXP schema archives" depends="generate-schema-archive-rnc, generate-schema-archive-xsd"/>
+
     <target name="validate-profile-transformation" description="Validates transformation profile.">
         <java fork="true" jar="${jing.jar}">
             <arg value="-c"/>
@@ -78,6 +114,47 @@
     <target name="validate-profiles"
 	    depends="validate-profile-transformation,validate-profile-presentation,validate-profile-full"/>
 
+    <target name="validate-example-1" description="Validates Example 1.">
+        <!-- validate using RNC schema -->
+        <java fork="true" jar="${jing.jar}">
+            <arg value="-c"/>
+            <arg value="${rnc.schema}"/>
+            <arg value="${examples.dir}/ex1.xml"/>
+        </java>
+        <!-- validate using XSD schema -->
+        <schemavalidate fullchecking="true" warn="true">
+          <schema namespace="http://www.w3.org/ns/ttml" file="${xsd.schema}"/>
+          <fileset dir="${examples.dir}">
+            <include name="ex3.xml"/>
+          </fileset>
+        </schemavalidate>
+    </target>
+
+    <target name="validate-example-3" description="Validates Example 3.">
+        <!-- validate using RNC schema -->
+        <java fork="true" jar="${jing.jar}">
+            <arg value="-c"/>
+            <arg value="${rnc.schema}"/>
+            <arg value="${examples.dir}/ex3-all-elements.xml"/>
+        </java>
+        <java fork="true" jar="${jing.jar}">
+            <arg value="-c"/>
+            <arg value="${rnc.schema}"/>
+            <arg value="${examples.dir}/ex3-all-styles.xml"/>
+        </java>
+        <!-- validate using XSD schema -->
+        <schemavalidate fullchecking="true" warn="true">
+          <schema namespace="http://www.w3.org/ns/ttml" file="${xsd.schema}"/>
+          <fileset dir="${examples.dir}">
+            <include name="ex3-all-elements.xml"/>
+            <include name="ex3-all-styles.xml"/>
+          </fileset>
+        </schemavalidate>
+    </target>
+
+    <target name="validate-examples"
+	    depends="validate-example-1, validate-example-3"/>
+
     <target name="validate-xsl" description="Validates all XML files.">
         <xmlvalidate lenient="true">
             <fileset dir="." includes="*.xsl"/>
@@ -110,101 +187,30 @@
         <xmlvalidate lenient="false" warn="yes" file="ttml11.xml"/>
     </target>
 
-    <target name="validate" depends="validate-xsl,validate-svg,validate-tt-specs,validate-schema-rnc,validate-profiles"/>
+    <target name="validate-tt-specs-dont-build-escapes" description="Validates all Timed Text spec files.">
+        <xmlvalidate lenient="false" warn="yes" file="ttml11.xml"/>
+    </target>
 
-    <target name="updateAcks"
-        description="Update acknowledgements. Before running this, 
-	update ackcurrent.xml via  and ackold.xml
-	via http://www.w3.org/2000/09/dbwg/details?group=34314&amp;former=1&amp;public=1 .">
-        <get src="http://www.w3.org/2000/09/dbwg/details?group=34314&amp;public=1" dest="ackcurrent.xml"/>
-        <get src="http://www.w3.org/2000/09/dbwg/details?group=34314&amp;former=1&amp;public=1" dest="ackold.xml"/>
-        <java fork="true" classname="net.sf.saxon.Transform">
-            <classpath refid="saxon8.classpath"/>
-            <arg value="-o"/>
-            <arg value="acknowledgements-current.txt"/>
-            <arg value="ackcurrent.xml"/>
-            <arg value="generate-acknowledgements.xsl"/>
-            <arg value="participating=1"/>
-        </java>
-        <java fork="true" classname="net.sf.saxon.Transform">
-            <classpath refid="saxon8.classpath"/>
-            <arg value="-o"/>
-            <arg value="acknowledgements-old.txt"/>
-            <arg value="ackold.xml"/>
-            <arg value="generate-acknowledgements.xsl"/>
-            <arg value="participating=0"/>
-        </java>
-    </target>
+    <target name="validate" depends="validate-schemas,validate-examples,validate-xsl,validate-svg,validate-tt-specs,validate-schema-rnc,validate-profiles"/>
 
     <target name="html" description="Transforms xml into html.">
         <echo>Generating ttml11.html</echo>
         <java fork="true" classname="net.sf.saxon.Transform">
             <classpath refid="saxon8.classpath"/>
             <arg value="-o"/>
-            <arg value="${htmlOutputDir}ttml11.html"/>
+            <arg value="${html.dir}/${html.name}"/>
             <arg value="ttml11.xml"/>
             <arg value="${stylesheet}"/>
             <arg value="showAssertions=true"/>
         </java>    
     </target>
 
-    <path id="diffmk.classpath">
-        <pathelement location="${basedir}/diffmk.jar"/>
-        <pathelement location="${basedir}/DiffMk.properties"/>
-    </path>
-    <target name="generateXMLdiff">
-  <java classname="com.sun.xtc.diffmk.DiffMk" fork="true">
-            <arg value="-doctype"/>
-            <arg value="xmlspec"/>
-            <arg value="-diff"/>
-            <arg value="both"/>
-            <arg value="-words"/>
-            <arg value="tt-tr${last-public-draft}.xml"/>
-            <arg value="ttml11.xml"/>
-            <arg value="tt-diff${last-public-draft}.xml"/>
-            <classpath path="diffmk.jar:DiffMk.properties"> </classpath>
-        </java>
-    </target>
-    <target name="generateHTMLdiff">
-        <java fork="true" classname="net.sf.saxon.Transform">
-            <classpath refid="saxon8.classpath"/>
-            <arg value="-o"/>
-            <arg value="${htmlOutputDir}tt-diff${last-public-draft}.html"/>
-            <arg value="tt-diff${last-public-draft}.xml"/>
-            <arg value="diffspec.xsl"/>
-        </java>
-    </target>
-
-    <target name="postprocess-diff">
-      <java fork="true" classname="net.sf.saxon.Transform">
-            <classpath refid="saxon8.classpath"/>
-            <arg value="-o"/>
-            <arg value="temp-tt-diff${last-public-draft}.xml"/>
-            <arg value="tt-diff${last-public-draft}.xml"/>
-            <arg value="diff-postprocess.xsl"/>
-        </java>
-        <copy tofile="tt-diff${last-public-draft}.xml"
-            file="temp-tt-diff${last-public-draft}.xml" overwrite="true"/>
-        <delete file="temp-tt-diff${last-public-draft}.xml"/>
-    </target>
-
-    <target name="diff" depends="generateXMLdiff, postprocess-diff, generateHTMLdiff"/>
-
-    <target name="changelog" description="Update the CVS change log to be added into the specification">
-      <!--        <cvschangelog destfile="changelog.xml"/> -->
-      <get src="http://www.w3.org/2000/06/webdata/xslt?xslfile=http%3A%2F%2Fwww.w3.org%2F2008%2F05%2Fcvswebrss.xsl&amp;xmlfile=http%3A%2F%2Fcgi.w3.org%2Fcgi-bin%2Ftidy%3FdocAddr%3Dhttp%253A%252F%252Fdev.w3.org%252Fcvsweb%252F2008%252Fws%252Ftt%252Fttml11.xml%26forceXML%3Don" dest="changelog.xml"/>
-    </target>
-
-    <target name="generate" description="Generate the specification without updating changelog and acknowledgments sections"
-	    depends="validate-tt-specs,html">
-      <echo>WARNING: changelog.xml and acknowledgments.xml MAY be out of date. Use "main" target if necessary.</echo>
+    <target name="generate" description="Generate the specification without updating escaped entities."
+	    depends="generate-schema-archives,validate-tt-specs,html">
     </target>
     
-    <target name="main" description="Generate the specification for a CVS commit"
-	    depends="changelog,validate-tt-specs,html">
-<!--	    depends="updateAcks,changelog,validate-tt-specs,html"> -->
-      <echo>ttml11.html is ready for CVS commit</echo>
-      <echo>Use target "generate" to avoid regenerating changelog.xml and acknowledgments.xml</echo>
+    <target name="sg" description="Shortened generation of the specification without updating changelog and acknowledgments sections, but without rebuilding escapes."
+	    depends="generate-schema-archives,validate-tt-specs-dont-build-escapes,html">
     </target>
 
 </project>
--- a/ttml11/spec/changelog.xml	Tue Jul 09 11:28:27 2013 -0600
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,13 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<feed xmlns:h="http://www.w3.org/1999/xhtml" xmlns="http://www.w3.org/2005/Atom">
-   <id>http://dev.w3.org</id>
-   <updated>-01-TZ</updated>
-   <title> CVS log</title>
-   <author>
-      <name>World Wide Web Consortium</name>
-      <uri>http://dev.w3.org</uri>
-   </author>
-   <link rel="alternate" type="text/html" href="http://dev.w3.org"/>
-   <link rel="self" href="http://dev.w3.org"/>
-   <rights>World Wide Web Consortium</rights>
-</feed>
\ No newline at end of file
Binary file ttml11/spec/diffmk.jar has changed
--- a/ttml11/spec/diffspec.xsl	Tue Jul 09 11:28:27 2013 -0600
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,373 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<!--This file was created automatically by html2xhtml-->
-<!--from the HTML stylesheets. Do not edit this file.-->
-<!-- Version: $Id$ --><!-- Stylesheet for @diff markup in XMLspec --><!-- Author: Norman Walsh (Norman.Walsh@East.Sun.COM) --><!-- Date Created: 2000.07.21 --><!-- This stylesheet is copyright (c) 2000 by its authors.  Free
-     distribution and modification is permitted, including adding to
-     the list of authors and copyright holders, as long as this
-     copyright notice is maintained. --><!-- This stylesheet attempts to implement the XML Specification V2.1
-     DTD.  Documents conforming to earlier DTDs may not be correctly
-     transformed.
-
-     This stylesheet supports the use of change-markup with the @diff
-     attribute. If you use @diff, you should always use this stylesheet.
-     If you want to turn off the highlighting of differences, use this
-     stylesheet, but set show.diff.markup to 0.
-
-     Using the original xmlspec stylesheet with @diff markup will cause
-     @diff=del text to be presented.
---><!-- ChangeLog:
-     25 Sep 2000: (Norman.Walsh@East.Sun.COM)
-       - Use inline diff markup (as opposed to block) for name and
-         affiliation
-       - Handle @diff='del' correctly in bibl and other list-contexts.
-     14 Aug 2000: (Norman.Walsh@East.Sun.COM)
-       - Support additional.title param
-     27 Jul 2000: (Norman.Walsh@East.Sun.COM)
-       - Fix HTML markup problem with diff'd authors in authlist
-     26 Jul 2000: (Norman.Walsh@East.Sun.COM)
-       - Update pointer to latest xmlspec-stylesheet.
-     21 Jul 2000: (Norman.Walsh@East.Sun.COM)
-       - Initial version
---><xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0">
-
-<xsl:import href="xmlspec.xsl"/>
-
-<xsl:param name="show.diff.markup" select="1"/>
-
-<xsl:param name="additional.css">
-<xsl:if test="$show.diff.markup != '0'">
-<xsl:text>
-div.diff-add  { background-color: #FFFF99; }
-div.diff-del  { text-decoration: line-through; }
-div.diff-chg  { background-color: #99FF99; }
-div.diff-off  {  }
-
-span.diff-add { background-color: #FFFF99; }
-span.diff-del { text-decoration: line-through; }
-span.diff-chg { background-color: #99FF99; }
-span.diff-off {  }
-
-td.diff-add   { background-color: #FFFF99; }
-td.diff-del   { text-decoration: line-through }
-td.diff-chg   { background-color: #99FF99; }
-td.diff-off   {  }
-</xsl:text>
-</xsl:if>
-</xsl:param>
-
-<xsl:param name="additional.title">
-  <xsl:if test="$show.diff.markup != '0'">
-    <xsl:text>Review Version</xsl:text>
-  </xsl:if>
-</xsl:param>
-
-<xsl:param name="called.by.diffspec" select="1"/>
-
-<!-- ==================================================================== -->
-
-  <!-- spec: the specification itself -->
-  <xsl:template match="spec">
-    <html xmlns="http://www.w3.org/1999/xhtml">
-      <xsl:if test="header/langusage/language">
-        <xsl:attribute name="lang">
-          <xsl:value-of select="header/langusage/language/@id"/>
-        </xsl:attribute>
-      </xsl:if>
-      <head>
-	
-        <title>
-          <xsl:apply-templates select="header/title"/>
-          <xsl:if test="header/version">
-            <xsl:text> </xsl:text>
-            <xsl:apply-templates select="header/version"/>
-          </xsl:if>
-          <xsl:if test="$additional.title != ''">
-            <xsl:text> -- </xsl:text>
-            <xsl:value-of select="$additional.title"/>
-	  </xsl:if>
-        </title>
-        <xsl:call-template name="css"/>
-      </head>
-      <body>
-        <xsl:if test="$show.diff.markup != 0">
-          <div>
-            <p>The presentation of this document has been augmented to
-            identify changes from a previous version. Three kinds of changes
-            are highlighted: <span class="diff-add">new, added text</span>,
-            <span class="diff-chg">changed text</span>, and
-            <span class="diff-del">deleted text</span>.</p>
-            <hr/>
-          </div>
-        </xsl:if>
-        <xsl:apply-templates/>
-        <xsl:if test="//footnote[not(ancestor::table)]">
-          <hr/>
-          <div class="endnotes">
-            <xsl:text>
-</xsl:text>
-            <h3>
-              <xsl:call-template name="anchor">
-                <xsl:with-param name="conditional" select="0"/>
-                <xsl:with-param name="default.id" select="'endnotes'"/>
-              </xsl:call-template>
-              <xsl:text>End Notes</xsl:text>
-            </h3>
-            <dl>
-              <xsl:apply-templates select="//footnote[not(ancestor::table)]" mode="notes"/>
-            </dl>
-          </div>
-        </xsl:if>
-      </body>
-    </html>
-  </xsl:template>
-
-<!-- ==================================================================== -->
-
-<xsl:template name="diff-markup">
-  <xsl:param name="diff">off</xsl:param>
-  <xsl:choose>
-    <xsl:when test="ancestor::scrap">
-      <!-- forget it, we can't add stuff inside tables -->
-      <!-- handled in base stylesheet -->
-      <xsl:apply-imports/>
-    </xsl:when>
-    <xsl:when test="self::gitem or self::bibl">
-      <!-- forget it, we can't add stuff inside dls; handled below -->
-      <xsl:apply-imports/>
-    </xsl:when>
-    <xsl:when test="ancestor-or-self::phrase">
-      <span xmlns="http://www.w3.org/1999/xhtml" class="diff-{$diff}">
-	<xsl:apply-imports/>
-      </span>
-    </xsl:when>
-    <xsl:when test="ancestor::p and not(self::p)">
-      <span xmlns="http://www.w3.org/1999/xhtml" class="diff-{$diff}">
-	<xsl:apply-imports/>
-      </span>
-    </xsl:when>
-    <xsl:when test="ancestor-or-self::affiliation">
-      <span xmlns="http://www.w3.org/1999/xhtml" class="diff-{$diff}">
-	<xsl:apply-imports/>
-      </span>
-    </xsl:when>
-    <xsl:when test="ancestor-or-self::name">
-      <span xmlns="http://www.w3.org/1999/xhtml" class="diff-{$diff}">
-	<xsl:apply-imports/>
-      </span>
-    </xsl:when>
-    <xsl:otherwise>
-      <div xmlns="http://www.w3.org/1999/xhtml" class="diff-{$diff}">
-	<xsl:apply-imports/>
-      </div>
-    </xsl:otherwise>
-  </xsl:choose>
-</xsl:template>
-
-<xsl:template match="*[@diff='chg']">
-  <xsl:choose>
-    <xsl:when test="$show.diff.markup != 0">
-      <xsl:call-template name="diff-markup">
-	<xsl:with-param name="diff">chg</xsl:with-param>
-      </xsl:call-template>
-    </xsl:when>
-    <xsl:otherwise>
-      <xsl:apply-imports/>
-    </xsl:otherwise>
-  </xsl:choose>
-</xsl:template>
-
-<xsl:template match="*[@diff='add']">
-  <xsl:choose>
-    <xsl:when test="$show.diff.markup != 0">
-      <xsl:call-template name="diff-markup">
-	<xsl:with-param name="diff">add</xsl:with-param>
-      </xsl:call-template>
-    </xsl:when>
-    <xsl:otherwise>
-      <xsl:apply-imports/>
-    </xsl:otherwise>
-  </xsl:choose>
-</xsl:template>
-
-<xsl:template match="*[@diff='del']">
-  <xsl:choose>
-    <xsl:when test="$show.diff.markup != 0">
-      <xsl:call-template name="diff-markup">
-	<xsl:with-param name="diff">del</xsl:with-param>
-      </xsl:call-template>
-    </xsl:when>
-    <xsl:otherwise>
-      <!-- suppress deleted markup -->
-    </xsl:otherwise>
-  </xsl:choose>
-</xsl:template>
-
-<xsl:template match="*[@diff='off']">
-  <xsl:choose>
-    <xsl:when test="$show.diff.markup != 0">
-      <xsl:call-template name="diff-markup">
-	<xsl:with-param name="diff">off</xsl:with-param>
-      </xsl:call-template>
-    </xsl:when>
-    <xsl:otherwise>
-      <xsl:apply-imports/>
-    </xsl:otherwise>
-  </xsl:choose>
-</xsl:template>
-
-<!-- ================================================================= -->
-
-  <xsl:template match="bibl[@diff]" priority="1">
-    <xsl:variable name="dt">
-      <xsl:if test="@id">
-	<a xmlns="http://www.w3.org/1999/xhtml" name="{@id}"/>
-      </xsl:if>
-      <xsl:choose>
-	<xsl:when test="@key">
-	  <xsl:value-of select="@key"/>
-	</xsl:when>
-	<xsl:otherwise>
-	  <xsl:value-of select="@id"/>
-	</xsl:otherwise>
-      </xsl:choose>
-    </xsl:variable>
-    <xsl:variable name="dd">
-      <xsl:apply-templates/>
-      <xsl:if test="@href">
-        <xsl:text>  (See </xsl:text>
-        <xsl:value-of select="@href"/>
-        <xsl:text>.)</xsl:text>
-      </xsl:if>
-    </xsl:variable>
-
-    <xsl:choose>
-      <xsl:when test="@diff and $show.diff.markup != 0">
-	<dt xmlns="http://www.w3.org/1999/xhtml" class="label">
-	  <span class="diff-{@diff}">
-	    <xsl:copy-of select="$dt"/>
-	  </span>
-	</dt>
-	<dd xmlns="http://www.w3.org/1999/xhtml">
-	  <div class="diff-{@diff}">
-	    <xsl:copy-of select="$dd"/>
-	  </div>
-	</dd>
-      </xsl:when>
-      <xsl:when test="@diff='del' and $show.diff.markup = 0">
-	<!-- suppressed -->
-      </xsl:when>
-      <xsl:otherwise>
-	<dt xmlns="http://www.w3.org/1999/xhtml" class="label">
-	  <xsl:copy-of select="$dt"/>
-	</dt>
-	<dd xmlns="http://www.w3.org/1999/xhtml">
-	  <xsl:copy-of select="$dd"/>
-	</dd>
-      </xsl:otherwise>
-    </xsl:choose>
-  </xsl:template>
-
-  <xsl:template match="gitem/label">
-    <xsl:variable name="diffval" select="ancestor-or-self::*/@diff"/>
-    <xsl:choose>
-      <xsl:when test="$diffval != '' and $show.diff.markup != 0">
-	<dt xmlns="http://www.w3.org/1999/xhtml" class="label">
-	  <span class="diff-{ancestor-or-self::*/@diff}">
-	    <xsl:apply-templates/>
-	  </span>
-	</dt>
-      </xsl:when>
-      <xsl:when test="$diffval='del' and $show.diff.markup = 0">
-	<!-- suppressed -->
-      </xsl:when>
-      <xsl:otherwise>
-	<dt xmlns="http://www.w3.org/1999/xhtml" class="label">
-	  <xsl:apply-templates/>
-	</dt>
-      </xsl:otherwise>
-    </xsl:choose>
-  </xsl:template>
-
-  <xsl:template match="gitem/def">
-    <xsl:variable name="diffval" select="ancestor-or-self::*/@diff"/>
-    <xsl:choose>
-      <xsl:when test="$diffval != '' and $show.diff.markup != 0">
-	<dd xmlns="http://www.w3.org/1999/xhtml">
-	  <div class="diff-{ancestor-or-self::*/@diff}">
-	    <xsl:apply-templates/>
-	  </div>
-	</dd>
-      </xsl:when>
-      <xsl:when test="$diffval='del' and $show.diff.markup = 0">
-	<!-- suppressed -->
-      </xsl:when>
-      <xsl:otherwise>
-	<dd xmlns="http://www.w3.org/1999/xhtml">
-	  <xsl:apply-templates/>
-	</dd>
-      </xsl:otherwise>
-    </xsl:choose>
-  </xsl:template>
-
-  <!-- authlist: list of authors (editors, really) -->
-  <!-- called in enforced order from header's template, in <dl>
-       context -->
-  <xsl:template match="authlist[@diff]">
-    <xsl:choose>
-      <xsl:when test="$show.diff.markup != 0">
-	<dt xmlns="http://www.w3.org/1999/xhtml">
-	  <span class="diff-{ancestor-or-self::*/@diff}">
-	    <xsl:text>Editor</xsl:text>
-	    <xsl:if test="count(author) &gt; 1">
-	      <xsl:text>s</xsl:text>
-	    </xsl:if>
-	    <xsl:text>:</xsl:text>
-	  </span>
-	</dt>
-      </xsl:when>
-      <xsl:when test="@diff='del' and $show.diff.markup = 0">
-	<!-- suppressed -->
-      </xsl:when>
-      <xsl:otherwise>
-	<dt xmlns="http://www.w3.org/1999/xhtml">
-	  <xsl:text>Editor</xsl:text>
-	  <xsl:if test="count(author) &gt; 1">
-	    <xsl:text>s</xsl:text>
-	  </xsl:if>
-	  <xsl:text>:</xsl:text>
-	</dt>
-      </xsl:otherwise>
-    </xsl:choose>
-    <xsl:apply-templates/>
-  </xsl:template>
-
-  <!-- author: an editor of a spec -->
-  <!-- only appears in authlist -->
-  <!-- called in <dl> context -->
-  <xsl:template match="author[@diff]" priority="1">
-    <xsl:choose>
-      <xsl:when test="@diff and $show.diff.markup != 0">
-	<dd xmlns="http://www.w3.org/1999/xhtml">
-	  <span class="diff-{ancestor-or-self::*/@diff}">
-	    <xsl:apply-templates/>
-	    <xsl:if test="@role = '2e'">
-	      <xsl:text> - Second Edition</xsl:text>
-	    </xsl:if>
-	  </span>
-	</dd>
-      </xsl:when>
-      <xsl:when test="@diff='del' and $show.diff.markup = 0">
-	<!-- suppressed -->
-      </xsl:when>
-      <xsl:otherwise>
-	<dd xmlns="http://www.w3.org/1999/xhtml">
-	  <xsl:apply-templates/>
-	  <xsl:if test="@role = '2e'">
-	    <xsl:text> - Second Edition</xsl:text>
-	  </xsl:if>
-	</dd>
-      </xsl:otherwise>
-    </xsl:choose>
-  </xsl:template>
-
-</xsl:stylesheet>
--- a/ttml11/spec/editlist.txt	Tue Jul 09 11:28:27 2013 -0600
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,125 +0,0 @@
-********************************************************************************
-*                                  EDIT LIST                                   *
-********************************************************************************
-
-ALREADY IMPLEMENTED
-
-[GA-A-024-20081214] 7.1.{4,6}   correct prose to accommodate nested divs and spans
-[GA-A-026-20090130] *           define default region
-[GA-A-027-20081214] 9.3.2 (7)   map anonymous spans to fo:inline only when parent is p or span
-[GA-A-028-20090130] *           move tts:extent from body to tt element
-[GA-A-029-20090130] *           fix inconsistency regarding time containment semantics
-[GA-A-030-20090130] 10.2        clarify semantics for dur and end
-[GA-A-032-20090130] 9.1.2       add ttm:role to region element
-[GA-A-033-20090415] *           unify and better formalize style resolution process
-[GA-A-034-20090427] 8.2.7       add "rollUp" shorthand value to tts:dynamicFlow
-[GA-A-035-20090504] 3.2         subdivide into transformation and presentation conformance
-[GA-A-036-20090504] C           update schemas
-[GA-I-008-20090415] 12.2.2      add "description" value to ttm:role enumeration
-[GA-I-009-20090504] 11,12       add examples to metadata and animation element vocabulary
-[GA-I-012-20090130] *           define default region
-[GA-I-015-20090415] *           change XML and XML Namespace references
-[GA-I-016-20081214] 10.2.*      fix incorrect reference to smil2 section (should be 10.4.1)
-[GA-I-017-20081214] 8.3.4       correct definition of <duration> syntax to <digit>+
-[GA-I-027-20081214] 8.2.20      correct names of textDecoration values (lineThrough)
-[GA-I-028-20090130] 8.2.13      elaborate prose to accommodate nested spans
-[GA-I-032-20090415] 8.4.3       style chaining an left preference
-[GA-I-033-20090415] 8.3.{5,14}  allow unquoted font family name that contains whitespace
-[GA-I-034-20090130] 9.3         elaborate processing of anonymous spans
-[GA-I-035-20090415] 8.3.1       opacity float value
-[GA-I-036-20090130] 8.2         inheritance by anonymous spans
-[GA-I-037-20081214] 9.3.2 (7)   map anonymous spans to fo:inline only when parent is p or span
-[GA-I-040-20090415] *           unify and better formalize style resolution process
-[GA-I-041-20090415] 7.1.3       change body to parallel time containment as default
-[GA-I-042-20090130] 9.3         processing in absence of region attribute
-[GA-I-043-20090415] 9.3.2       correct content hierarchy region mapping example code
-[GA-I-044-20081214] B.4         change typo "withing" to "within"
-[GA-I-045-20081214] 8.2.24      remove extra '"' at end of last line of wrap option example
-[GA-I-046-20081214] 8.2.23      missing inheritance and percentage constraints
-[GA-I-048-20090130] *           specify requiredExtensions and requiredFeatures
-[GA-I-050-20090130] *           improve consistency of style association prose on content elts
-[GA-I-051-20090130] 8.2.5       allow tts:display to apply to region element
-[GA-I-052-20090130] 8.3         fix order and missing entry in list of style value expressions
-[GA-I-054-20090427] 8.{2,4}     remove explicit inheritance
-[GA-I-055-20090427] 8.2.{20,21} make textDecoration and textOutline inheritable
-[GA-I-056-20090504] 8.2.20      fix indentation of tts:textDecoration example
-[GA-I-059-20090427] 8.2.*       make all style properties animatable
-[GA-I-060-20090504] 5.2,6.1     enhance profile specification mechanism
-[GA-I-061-20090427] B.3.{1,2}   correct flow interval computation with definite rate
-[GA-I-062-20090427] B.2         clarify meaning of "difference" in contents of flow buffer
-[GA-I-063-20090427] B.2         clarify meaning of "logical content position"
-[GA-I-064-20090427] B.5         clarify timeline used for dynamic flow
-[GA-I-065-20090427] 8.2.7,B     account for side effects of animation
-[GA-I-066-20090427] B.2         clarify assumptions regarding flow buffer state persistence
-[GA-I-067-20090427] B.2         clarify handling of temporal style changes w.r.t. flow buffer
-[GA-I-068-20090504] 9.3.3       ensure last block of body's block is filled out to region
-[GA-I-069-20090504] 8.2.8       mandate explicit lengths for tts:extent on tt:tt element
-[GA-I-070-20090504] 8.2.16      clarify "region's width and height were infinite"
-[GA-I-073-20090427] 1.2         remove superfluous text
-[GA-I-075-20090504] 5.2         clarify use of optional feature/extension
-[GA-I-076-20090427] 8.2.13      fix typo
-[GA-I-077-20090427] 8.2.*       add missing prose regarding anonymous spans
-[GA-I-078-20090427] 8.3.14      remove spurious reference to whitespace S syntactic element
-[GA-I-079-20090427] G           update XSL reference to XSL 1.1
-[GA-I-080-20090504] I           remove sample code appendix
-[GA-I-081-20090427] 8.3.6,B     remove 'pixel' flow unit and flow transitions
-[GA-I-082-20090427] 8.2.{13,16} change 'scroll' value to 'dynamic' for tts:overflow
-[GA-I-083-20090427] B.4         clarify flow operations prose logical vs formatted units
-[GA-I-084-20090427] 8.3.6       specify semantics if smooth or fade flow style not supported
-[GA-I-085-20090504] 6.2.4       ttp:frameRateMultiplier - missing default for denominator
-[GA-I-086-20090504] 8.3.6,B     tts:dynamicFlow - remove fade, within()
-[GA-I-087-20090504] 5.1         change TT style namespace value to #styling instead of #style
-[GA-I-088-20090504] *           remove editorial notes
-[GA-I-089-20090504] 12.2.2      ttm:role - allow multiple tokens
-[GA-I-090-20090504] 8.2.14      improve opacity semantics
-[GA-I-091-20090504] 8.2.*       implement style defaults
-[GA-I-092-20090529] 6.1.{2,4}   change base to xml:base
-[GA-I-093-20090529] 6.1.{2,4}   change base to xml:base
-[GA-I-094-20090529] 5.1,I       specify that TT namespaces are mutable
-[GA-I-096-20090529] G.3         create DFXP "Full" profile, requiring all features
-[GA-I-097-20090529] 12.1.1      fix metadata content model
-[GA-I-098-20090529] B           eliminate or clarify clear timing
-[GA-I-099-20090529] B           clarify semantics of blocked fill operation
-[GA-I-100-20090529] 8.3.6,B     remove block and inline fill units
-[GA-I-101-20090529] 8.2.7,I     add note justifying rollUp interval
-[GA-I-102-20090529] 8.[23].7,B  change names of intra() and inter() flow interval functions
-[GA-I-103-20090529] 8.2.7       proscribe multiple instances of same flow function
-[GA-I-104-20090529] B.{2,3}     clarify flow buffer language
-[GA-I-105-20090529] 8.2.16,B.4  clarify interaction between dynamic flow and wrap property
-[GA-I-106-20090529] 9.4,E       clarify line breaking, add line breaking feature designator
-[GA-I-108-20090529] G.1         remove redundant transformation requirement in transform profile
-[GA-I-110-20090529] 7.1.2       explicitly allow foreign attributes on head element
-[GA-I-111-20090529] 12.1.1      fix note regarding context of usage of metadata items
-[GA-I-112-20090529] 5.3.2       remove style, metadata, and parameter extension namespaces
-[GA-I-113-20090529] 3,E         remove circularity in definition of processor conformance
-[GA-I-114-20090529] E.2,G.2     reduce presentation profile requirements
-[GA-I-115-20090529] E.2,G.1     expand transformation profile requirements
-[GA-I-116-20090529] 5.2,6.{1,2} aggregate certain ttp:profile related text into one place
-[GA-I-117-20090529] 5.2,6.1     add 'use' value to ttp:{feature,extension} value attribute
-[GA-I-118-20090530] 9.3.2       clarify region association algorithm
-[GA-I-119-20090720] C.1         change #style to #styling, remove #*-extension NS in RNC schema
-[GA-I-120-20090720] C.1         add missing direction and unicodeBidi styles in RNC schema
-[GA-I-121-20090720] C.1         fix RNC schema problem with regard to ttm:agent
-[GA-I-122-20090720] 6.2.6       ttp:pixelAspectRatio - eliminate ':' separator
-[GA-I-122-20090720] 6.2.4       ttp:frameRateMultiplier - eliminate ':' separator
-[GA-I-123-20090720] 6.2.4       ttp:frameRateMultiplier - constrain numerator to non-zero
-[GA-I-125-20090720] 8.2.6       tts:displayAlign - remove inheritance
-[GA-I-126-20090720] 8.3.7       tts:dynamicFlow - needs flow style duration parameter
-[GA-I-128-20090720] B.5         tts:dynamicFlow - fix typos
-[GA-I-131-20090720] 5.1,6.1     profile, feature, and extension namespaces need trailing '/'
-[GA-I-132-20090720] *           miscellaneous typos
-[GA-I-133-20090720] 8.2.14      improve language regarding 'transparency'
-[GA-I-134-20090720] 8.2.15      reorder constraints on root container origin
-[GA-I-135-20090720] 10.2.3      add note regarding presence of both 'dur' and 'end' attributes
-[GA-I-136-20090720] 8.2.10      add note upon first use of 'c' length metric
-[GA-I-137-20090720] 12.1.1      tt:metadata - add example of foreign namespace element usage
-[GA-I-140-20090720] 10.2.3      @dur - add note on meaning of clock-time expressions
-[GA-I-141-20090720] 6.2.5,10.2.3 @dur - constrain usage with discontinuous marker mode
-[GA-I-142-20090720] *           change name of ttp:smpteMode to ttp:dropMode
-[GA-I-145-20090720] 4.1         elaborate note about potential false negative using RNC schema
-[GA-I-146-20090720] 8.2.7       tts:dynamicFlow - prohibit instances of same <flowFunction>
-[GA-I-127-20090905] 8.3.7,B     add 'break' flow interval argument
-[GA-I-129-20090905] 8.2.7       use 'break' flow interval argument in tts:dynamicFlow example
-[GA-I-130-20090905] E,G         add, rename feature designations
-[GA-I-147-20090905] 6.2.11      clarify 'media time' when using clock timebase
-[GA-I-148-20090905] 10.4        clarify 'offset based time' when using media or continuous smpte timebase
--- a/ttml11/spec/entities.dtd	Tue Jul 09 11:28:27 2013 -0600
+++ b/ttml11/spec/entities.dtd	Tue Jul 09 14:39:28 2013 -0600
@@ -19,7 +19,6 @@
 
 <!ENTITY acknowledgements SYSTEM "acknowledgements.xml" >
 <!ENTITY acknowledgements-current SYSTEM "acknowledgements-current.txt" >
-<!ENTITY acknowledgements-old SYSTEM "acknowledgements-old.txt" >
 
 <!-- Misc entities. Feel free to add more -->
 
--- a/ttml11/spec/entitiescr.dtd	Tue Jul 09 11:28:27 2013 -0600
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,31 +0,0 @@
-<?xml version='1.0' encoding='ISO-8859-1' ?>
-
-<!--
-  Date parameters
-  -->
-<!ENTITY draft.year "2010">
-<!ENTITY draft.month "February">
-<!ENTITY draft.mm "02">
-<!ENTITY draft.day "23">
-<!ENTITY draft.dd "23">
-
-<!ENTITY draft.date "&draft.year;&draft.mm;&draft.dd;">
-
-<!ENTITY prefix "ttaf1-dfxp">
-
-<!ENTITY w3c.tr.latest  "http://www.w3.org/TR">	
-
-<!-- Latest version links. don't touch -->
-<!ENTITY latest "&w3c.tr.latest;/&prefix;/">
-
-<!ENTITY w3c.tr  "&w3c.tr.latest;/&draft.year;">	
-
-<!ENTITY document.role "public">
-
-<!-- The following is used for document .-->
-<!ENTITY document.status "W3C Candidate Recommendation">
-<!ENTITY w3c.status "CR">
-<!ENTITY doctype "cr">
-
-<!ENTITY w3c-designation
-  "&w3c.tr.latest;/&draft.year;/&w3c.status;-&prefix;-&draft.date;/">
--- a/ttml11/spec/entitieswd.dtd	Tue Jul 09 11:28:27 2013 -0600
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,31 +0,0 @@
-<?xml version='1.0' encoding='ISO-8859-1' ?>
-
-<!--
-  Date parameters
-  -->
-<!ENTITY draft.year "2009">
-<!ENTITY draft.month "June">
-<!ENTITY draft.mm "06">
-<!ENTITY draft.day "02">
-<!ENTITY draft.dd "02">
-
-<!ENTITY draft.date "&draft.year;&draft.mm;&draft.dd;">
-
-<!ENTITY prefix "ttaf1-dfxp">
-
-<!ENTITY w3c.tr.latest  "http://www.w3.org/TR">	
-
-<!-- Latest version links. don't touch -->
-<!ENTITY latest "&w3c.tr.latest;/&prefix;/">
-
-<!ENTITY w3c.tr  "&w3c.tr.latest;/&draft.year;">
-
-<!ENTITY document.role "public">
-
-<!-- The following is used for document .-->
-<!ENTITY document.status "W3C Working Draft">
-<!ENTITY w3c.status "WD">
-<!ENTITY doctype "wd">
-
-<!ENTITY w3c-designation
-  "&w3c.tr.latest;/&draft.year;/&w3c.status;-&prefix;-&draft.date;/">
--- a/ttml11/spec/examples/ex1-p-0.xml	Tue Jul 09 11:28:27 2013 -0600
+++ b/ttml11/spec/examples/ex1-p-0.xml	Tue Jul 09 14:39:28 2013 -0600
@@ -1,54 +1,64 @@
-<fo:root xmlns:fo="http://www.w3.org/1999/XSL/Format">
-  <fo:layout-master-set>
-    <fo:simple-page-master master-name="m1"
-      page-width="640px" page-height="480px">
-      <fo:region-body/>
-    </fo:simple-page-master>
-  </fo:layout-master-set>
-  <fo:page-sequence master-reference="m1">
-    <fo:flow flow-name="xsl-region-body">
-      <!-- region (r1) -->
-      <fo:block-container id="r1" absolute-position="absolute"
-        left="10px" top="100px" width="620px" height="96px"
-        background-color="black" display-align="center">
-        <!-- body (b1) -->
-        <fo:block id="b1-1">
-          <!-- div (d1) -->
-          <fo:block id="d1-1">
-            <!-- p (p1) -->
-            <fo:block id="p1" text-align="center">
-              <fo:inline font-size="40px" font-weight="bold"
-              color="red">Text 1</fo:inline>
-            </fo:block>
-          </fo:block>
-          <!-- body's space filler ->
-          <fo:block
-            space-after.optimum="96px"
-            space-after.maximum="96px"
-            space-after.conditionality="retain"/>
-        </fo:block>
-      </fo:block-container>
-      <!-- region (r2) -->
-      <fo:block-container id="r2" absolute-position="absolute"
-        left="10px" top="300px" width="620px" height="96px"
-        background-color="black" display-align="center">
-        <!-- body (b1) -->
-        <fo:block id="b1-2">
-          <!-- div (d1) -->
-          <fo:block id="d1-2">
-            <!-- p (p2) -->
-            <fo:block id="p2" text-align="center">
-              <fo:inline font-size="40px" font-weight="bold"
-              color="yellow">Text 2</fo:inline>
-            </fo:block>
-          </fo:block>
-          <!-- body's space filler ->
-          <fo:block
-            space-after.optimum="96px"
-            space-after.maximum="96px"
-            space-after.conditionality="retain"/>
-        </fo:block>
-      </fo:block-container>
-    </fo:flow>
-  </fo:page-sequence>
-</fo:root>
+<fo:root xmlns:fo="http://www.w3.org/1999/XSL/Format">
+  <fo:layout-master-set>
+    <fo:simple-page-master master-name="m1"
+      page-width="640px" page-height="480px">
+      <fo:region-body/>
+    </fo:simple-page-master>
+  </fo:layout-master-set>
+  <fo:page-sequence master-reference="m1">
+    <fo:flow flow-name="xsl-region-body">
+      <!-- region (r1) -->
+      <fo:block-container id="r1" absolute-position="absolute"
+        left="10px" top="100px" width="620px" height="96px"
+        background-color="black" display-align="center">
+        <!-- body (b1) -->
+        <fo:block id="b1-1">
+          <!-- body's space (before) filler -->
+          <fo:block
+            space-after.optimum="96px"
+            space-after.maximum="96px"
+            space-after.conditionality="retain"/>
+          <!-- div (d1) -->
+          <fo:block id="d1-1">
+            <!-- p (p1) -->
+            <fo:block id="p1" text-align="center">
+              <fo:inline font-size="40px" font-weight="bold"
+              color="red">Text 1</fo:inline>
+            </fo:block>
+          </fo:block>
+          <!-- body's space (after) filler -->
+          <fo:block
+            space-after.optimum="96px"
+            space-after.maximum="96px"
+            space-after.conditionality="retain"/>
+        </fo:block>
+      </fo:block-container>
+      <!-- region (r2) -->
+      <fo:block-container id="r2" absolute-position="absolute"
+        left="10px" top="300px" width="620px" height="96px"
+        background-color="black" display-align="center">
+        <!-- body (b1) -->
+        <fo:block id="b1-2">
+          <!-- body's space (before) filler -->
+          <fo:block
+            space-after.optimum="96px"
+            space-after.maximum="96px"
+            space-after.conditionality="retain"/>
+          <!-- div (d1) -->
+          <fo:block id="d1-2">
+            <!-- p (p2) -->
+            <fo:block id="p2" text-align="center">
+              <fo:inline font-size="40px" font-weight="bold"
+              color="yellow">Text 2</fo:inline>
+            </fo:block>
+          </fo:block>
+          <!-- body's space (after) filler -->
+          <fo:block
+            space-after.optimum="96px"
+            space-after.maximum="96px"
+            space-after.conditionality="retain"/>
+        </fo:block>
+      </fo:block-container>
+    </fo:flow>
+  </fo:page-sequence>
+</fo:root>
--- a/ttml11/spec/examples/ex1-x-0.xml	Tue Jul 09 11:28:27 2013 -0600
+++ b/ttml11/spec/examples/ex1-x-0.xml	Tue Jul 09 14:39:28 2013 -0600
@@ -1,38 +1,38 @@
-<tt tts:extent="640px 480px" xml:lang="en"
-  xmlns="http://www.w3.org/ns/ttml"
-  xmlns:tts="http://www.w3.org/ns/ttml#styling">
-  <head>
-    <layout>
-      <region xml:id="r1">
-        <style tts:origin="10px 100px"/>
-        <style tts:extent="620px 96px"/>
-        <style tts:fontSize="40px"/>
-        <style tts:fontWeight="bold"/>
-        <style tts:backgroundColor="black"/>
-        <style tts:color="red"/>
-        <style tts:textAlign="center"/>
-        <style tts:displayAlign="center"/>
-        <body xml:id="b1-1">
-          <div xml:id="d1-1">
-            <p xml:id="p1">Text 1</p>
-          </div>
-        </body>
-      </region>
-      <region xml:id="r2">
-        <style tts:origin="10px 300px"/>
-        <style tts:extent="620px 96px"/>
-        <style tts:fontSize="40px"/>
-        <style tts:fontWeight="bold"/>
-        <style tts:backgroundColor="black"/>
-        <style tts:color="yellow"/>
-        <style tts:textAlign="center"/>
-        <style tts:displayAlign="center"/>
-        <body xml:id="b1-2">
-          <div xml:id="d1-2">
-            <p xml:id="p2">Text 2</p>
-          </div>
-        </body>
-      </region>
-    </layout>
-  </head>
-</tt>
+<tt tts:extent="640px 480px" xml:lang="en"
+  xmlns="http://www.w3.org/ns/ttml"
+  xmlns:tts="http://www.w3.org/ns/ttml#styling">
+  <head>
+    <layout>
+      <region xml:id="r1">
+        <style tts:origin="10px 100px"/>
+        <style tts:extent="620px 96px"/>
+        <style tts:fontSize="40px"/>
+        <style tts:fontWeight="bold"/>
+        <style tts:backgroundColor="black"/>
+        <style tts:color="red"/>
+        <style tts:textAlign="center"/>
+        <style tts:displayAlign="center"/>
+        <body xml:id="b1-1">
+          <div xml:id="d1-1">
+            <p xml:id="p1">Text 1</p>
+          </div>
+        </body>
+      </region>
+      <region xml:id="r2">
+        <style tts:origin="10px 300px"/>
+        <style tts:extent="620px 96px"/>
+        <style tts:fontSize="40px"/>
+        <style tts:fontWeight="bold"/>
+        <style tts:backgroundColor="black"/>
+        <style tts:color="yellow"/>
+        <style tts:textAlign="center"/>
+        <style tts:displayAlign="center"/>
+        <body xml:id="b1-2">
+          <div xml:id="d1-2">
+            <p xml:id="p2">Text 2</p>
+          </div>
+        </body>
+      </region>
+    </layout>
+  </head>
+</tt>
--- a/ttml11/spec/examples/ex1-x-1.xml	Tue Jul 09 11:28:27 2013 -0600
+++ b/ttml11/spec/examples/ex1-x-1.xml	Tue Jul 09 14:39:28 2013 -0600
@@ -1,44 +1,44 @@
-<tt tts:extent="640px 480px" xml:lang="en"
-  xmlns="http://www.w3.org/ns/ttml"
-  xmlns:tts="http://www.w3.org/ns/ttml#styling">
-  <head>
-    <layout>
-      <region xml:id="r1">
-        <style tts:origin="10px 100px"/>
-        <style tts:extent="620px 96px"/>
-        <style tts:fontSize="40px"/>
-        <style tts:fontWeight="bold"/>
-        <style tts:backgroundColor="black"/>
-        <style tts:color="red"/>
-        <style tts:textAlign="center"/>
-        <style tts:displayAlign="center"/>
-        <body xml:id="b1-1">
-          <div xml:id="d1-1">
-            <p xml:id="p1">Text 1</p>
-          </div>
-          <div xml:id="d2-1">
-            <p xml:id="p4">Text 4</p>
-          </div>
-        </body>
-      </region>
-      <region xml:id="r2">
-        <style tts:origin="10px 300px"/>
-        <style tts:extent="620px 96px"/>
-        <style tts:fontSize="40px"/>
-        <style tts:fontWeight="bold"/>
-        <style tts:backgroundColor="black"/>
-        <style tts:color="yellow"/>
-        <style tts:textAlign="center"/>
-        <style tts:displayAlign="center"/>
-        <body xml:id="b1-2">
-          <div xml:id="d1-2">
-            <p xml:id="p2">Text 2</p>
-          </div>
-          <div xml:id="d2-2">
-            <p xml:id="p3">Text 3</p>
-          </div>
-        </body>
-      </region>
-    </layout>
-  </head>
-</tt>
+<tt tts:extent="640px 480px" xml:lang="en"
+  xmlns="http://www.w3.org/ns/ttml"
+  xmlns:tts="http://www.w3.org/ns/ttml#styling">
+  <head>
+    <layout>
+      <region xml:id="r1">
+        <style tts:origin="10px 100px"/>
+        <style tts:extent="620px 96px"/>
+        <style tts:fontSize="40px"/>
+        <style tts:fontWeight="bold"/>
+        <style tts:backgroundColor="black"/>
+        <style tts:color="red"/>
+        <style tts:textAlign="center"/>
+        <style tts:displayAlign="center"/>
+        <body xml:id="b1-1">
+          <div xml:id="d1-1">
+            <p xml:id="p1">Text 1</p>
+          </div>
+          <div xml:id="d2-1">
+            <p xml:id="p4">Text 4</p>
+          </div>
+        </body>
+      </region>
+      <region xml:id="r2">
+        <style tts:origin="10px 300px"/>
+        <style tts:extent="620px 96px"/>
+        <style tts:fontSize="40px"/>
+        <style tts:fontWeight="bold"/>
+        <style tts:backgroundColor="black"/>
+        <style tts:color="yellow"/>
+        <style tts:textAlign="center"/>
+        <style tts:displayAlign="center"/>
+        <body xml:id="b1-2">
+          <div xml:id="d1-2">
+            <p xml:id="p2">Text 2</p>
+          </div>
+          <div xml:id="d2-2">
+            <p xml:id="p3">Text 3</p>
+          </div>
+        </body>
+      </region>
+    </layout>
+  </head>
+</tt>
--- a/ttml11/spec/examples/ex1-x-2.xml	Tue Jul 09 11:28:27 2013 -0600
+++ b/ttml11/spec/examples/ex1-x-2.xml	Tue Jul 09 14:39:28 2013 -0600
@@ -1,38 +1,38 @@
-<tt tts:extent="640px 480px" xml:lang="en"
-  xmlns="http://www.w3.org/ns/ttml"
-  xmlns:tts="http://www.w3.org/ns/ttml#styling">
-  <head>
-    <layout>
-      <region xml:id="r1">
-        <style tts:origin="10px 100px"/>
-        <style tts:extent="620px 96px"/>
-        <style tts:fontSize="40px"/>
-        <style tts:fontWeight="bold"/>
-        <style tts:backgroundColor="black"/>
-        <style tts:color="red"/>
-        <style tts:textAlign="center"/>
-        <style tts:displayAlign="center"/>
-        <body xml:id="b1-1">
-          <div xml:id="d2-1">
-            <p xml:id="p4">Text 4</p>
-          </div>
-        </body>
-      </region>
-      <region xml:id="r2">
-        <style tts:origin="10px 300px"/>
-        <style tts:extent="620px 96px"/>
-        <style tts:fontSize="40px"/>
-        <style tts:fontWeight="bold"/>
-        <style tts:backgroundColor="black"/>
-        <style tts:color="yellow"/>
-        <style tts:textAlign="center"/>
-        <style tts:displayAlign="center"/>
-        <body xml:id="b1-2">
-          <div xml:id="d2-2">
-            <p xml:id="p3">Text 3</p>
-          </div>
-        </body>
-      </region>
-    </layout>
-  </head>
-</tt>
+<tt tts:extent="640px 480px" xml:lang="en"
+  xmlns="http://www.w3.org/ns/ttml"
+  xmlns:tts="http://www.w3.org/ns/ttml#styling">
+  <head>
+    <layout>
+      <region xml:id="r1">
+        <style tts:origin="10px 100px"/>
+        <style tts:extent="620px 96px"/>
+        <style tts:fontSize="40px"/>
+        <style tts:fontWeight="bold"/>
+        <style tts:backgroundColor="black"/>
+        <style tts:color="red"/>
+        <style tts:textAlign="center"/>
+        <style tts:displayAlign="center"/>
+        <body xml:id="b1-1">
+          <div xml:id="d2-1">
+            <p xml:id="p4">Text 4</p>
+          </div>
+        </body>
+      </region>
+      <region xml:id="r2">
+        <style tts:origin="10px 300px"/>
+        <style tts:extent="620px 96px"/>
+        <style tts:fontSize="40px"/>
+        <style tts:fontWeight="bold"/>
+        <style tts:backgroundColor="black"/>
+        <style tts:color="yellow"/>
+        <style tts:textAlign="center"/>
+        <style tts:displayAlign="center"/>
+        <body xml:id="b1-2">
+          <div xml:id="d2-2">
+            <p xml:id="p3">Text 3</p>
+          </div>
+        </body>
+      </region>
+    </layout>
+  </head>
+</tt>
--- a/ttml11/spec/examples/ex1.xml	Tue Jul 09 11:28:27 2013 -0600
+++ b/ttml11/spec/examples/ex1.xml	Tue Jul 09 14:39:28 2013 -0600
@@ -1,38 +1,38 @@
-<tt tts:extent="640px 480px" xml:lang="en"
-  xmlns="http://www.w3.org/ns/ttml"
-  xmlns:tts="http://www.w3.org/ns/ttml#styling">
-  <head>
-    <layout>
-      <region xml:id="r1">
-        <style tts:origin="10px 100px"/>
-        <style tts:extent="620px 96px"/>
-        <style tts:fontSize="40px"/>
-        <style tts:fontWeight="bold"/>
-        <style tts:backgroundColor="black"/>
-        <style tts:color="red"/>
-        <style tts:textAlign="center"/>
-        <style tts:displayAlign="center"/>
-      </region>
-      <region xml:id="r2">
-        <style tts:origin="10px 300px"/>
-        <style tts:extent="620px 96px"/>
-        <style tts:fontSize="40px"/>
-        <style tts:fontWeight="bold"/>
-        <style tts:backgroundColor="black"/>
-        <style tts:color="yellow"/>
-        <style tts:textAlign="center"/>
-        <style tts:displayAlign="center"/>
-      </region>
-    </layout>
-  </head>
-  <body xml:id="b1">
-    <div xml:id="d1" begin="0s" dur="2s">
-      <p xml:id="p1" region="r1">Text 1</p>
-      <p xml:id="p2" region="r2">Text 2</p>
-    </div>
-    <div xml:id="d2" begin="1s" dur="2s">
-      <p xml:id="p3" region="r2">Text 3</p>
-      <p xml:id="p4" region="r1">Text 4</p>
-    </div>
-  </body>
-</tt>
+<tt tts:extent="640px 480px" xml:lang="en"
+  xmlns="http://www.w3.org/ns/ttml"
+  xmlns:tts="http://www.w3.org/ns/ttml#styling">
+  <head>
+    <layout>
+      <region xml:id="r1">
+        <style tts:origin="10px 100px"/>
+        <style tts:extent="620px 96px"/>
+        <style tts:fontSize="40px"/>
+        <style tts:fontWeight="bold"/>
+        <style tts:backgroundColor="black"/>
+        <style tts:color="red"/>
+        <style tts:textAlign="center"/>
+        <style tts:displayAlign="center"/>
+      </region>
+      <region xml:id="r2">
+        <style tts:origin="10px 300px"/>
+        <style tts:extent="620px 96px"/>
+        <style tts:fontSize="40px"/>
+        <style tts:fontWeight="bold"/>
+        <style tts:backgroundColor="black"/>
+        <style tts:color="yellow"/>
+        <style tts:textAlign="center"/>
+        <style tts:displayAlign="center"/>
+      </region>
+    </layout>
+  </head>
+  <body xml:id="b1">
+    <div xml:id="d1" begin="0s" dur="2s">
+      <p xml:id="p1" region="r1">Text 1</p>
+      <p xml:id="p2" region="r2">Text 2</p>
+    </div>
+    <div xml:id="d2" begin="1s" dur="2s">
+      <p xml:id="p3" region="r2">Text 3</p>
+      <p xml:id="p4" region="r1">Text 4</p>
+    </div>
+  </body>
+</tt>
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/ttml11/spec/examples/ex2-paint-on.xml	Tue Jul 09 14:39:28 2013 -0600
@@ -0,0 +1,47 @@
+<tt ttp:cellResolution="60 20" xml:lang="en" xmlns="http://www.w3.org/ns/ttml"
+  xmlns:tts="http://www.w3.org/ns/ttml#parameter" xmlns:tts="http://www.w3.org/ns/ttml#styling">
+  <head>
+    <layout>
+      <region xml:id="r1" tts:color="white" tts:origin="10c 4c" tts:extent="40c 5c"/>
+    </layout>
+  </head>
+  <body>
+    <div begin="0s" end="25s">
+      <p>
+        <span begin="0s">Lorem</span>
+        <span begin="1s">ipsum</span>
+        <span begin="2s">dolor</span>
+        <span begin="3s">sit</span>
+      </p>
+      <p>
+        <span begin="4s">Amet</span>                
+        <span begin="5s">consectetur</span>
+        <span begin="6s">adipiscing</span>
+        <span begin="7s">elit</span>
+      </p>
+      <p>
+        <span begin="8s">Sed</span>
+        <span begin="9s">do</span>
+        <span begin="10s">eiusmod</span>
+        <span begin="11s">tempor</span>
+        <span begin="12s">incididunt </span>
+        <span begin="13s">labore</span>
+     </p>
+     <p>
+        <span begin="14s">et</span>
+        <span begin="15s">dolore</span>
+        <span begin="16s">magna</span>
+        <span begin="17s">aliqua</span>
+      </p>
+      <p>
+        <span begin="18s">Ut</span>
+        <span begin="19s">enim</span>
+        <span begin="20s">ad</span>
+        <span begin="21s">minim</span>
+        <span begin="22s">veniam</span>
+        <span begin="23s">quis,</span>
+        <span begin="24s">nostrud</span>
+      </p>
+    </div>
+  </body>
+</tt>
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/ttml11/spec/examples/ex2-pop-on.xml	Tue Jul 09 14:39:28 2013 -0600
@@ -0,0 +1,18 @@
+<tt ttp:cellResolution="60 20" xml:lang="en" xmlns="http://www.w3.org/ns/ttml"
+  xmlns:tts="http://www.w3.org/ns/ttml#parameter" xmlns:tts="http://www.w3.org/ns/ttml#styling">
+  <head>
+    <layout>
+      <region xml:id="r1" tts:color="white" tts:origin="10c 4c" tts:extent="40c 1c"/>
+      <region xml:id="r2" tts:color="yellow" tts:origin="10c 8c" tts:extent="40c 1c"/>
+    </layout>
+  </head>
+  <body>
+    <div timeContainer="seq">
+      <p region="r1" dur="4s">Lorem ipsum dolor sit</p
+      <p region="r2" dur="4s">Amet consectetur adipiscing elit</p>
+      <p region="r1" dur="6s">Sed do eiusmod tempor incididunt labore</p>
+      <p region="r2" dur="4s">et dolore magna aliqua</p>
+      <p region="r1" dur="7s">Ut enim ad minim veniam quis, nostrud</p>
+    </div>
+  </body>
+</tt>
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/ttml11/spec/examples/ex2-roll-up.xml	Tue Jul 09 14:39:28 2013 -0600
@@ -0,0 +1,17 @@
+<tt ttp:cellResolution="60 20" xml:lang="en" xmlns="http://www.w3.org/ns/ttml"
+  xmlns:tts="http://www.w3.org/ns/ttml#parameter" xmlns:tts="http://www.w3.org/ns/ttml#styling">
+  <head>
+    <layout>
+      <region xml:id="r1" tts:color="white" tts:origin="10c 4c" tts:extent="40c 2c"/>
+    </layout>
+  </head>
+  <body>
+    <div region="r1">
+      <p begin="0s" end="8s">Lorem ipsum dolor sit</p
+      <p begin="4s" end="12s">Amet consectetur adipiscing elit</p>
+      <p begin="8s" end="18s">Sed do eiusmod tempor incididunt labore</p>
+      <p begin="14s" end="25s">et dolore magna aliqua</p>
+      <p begin="18s" end="29s">Ut enim ad minim veniam quis, nostrud</p>
+    </div>
+  </body>
+</tt>
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/ttml11/spec/examples/ex3-all-elements.xml	Tue Jul 09 14:39:28 2013 -0600
@@ -0,0 +1,71 @@
+<tt:tt
+  tts:extent="640px 480px"
+  xml:lang="en"
+  xml:space="default"
+  ttp:cellResolution="3 5"
+  ttp:clockMode="utc"
+  ttp:dropMode="nonDrop"
+  ttp:frameRate="30"
+  ttp:frameRateMultiplier="1000 1001"
+  ttp:markerMode="discontinuous"
+  ttp:pixelAspectRatio="4 3"
+  ttp:profile="http://www.w3.org/ns/ttml/profile/dfxp-presentation"
+  ttp:subFrameRate="2"
+  ttp:tickRate="60"
+  ttp:timeBase="media"
+  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">
+  <tt:head>
+    <tt:metadata xml:id="m1"/>
+    <ttm:title xml:id="title">A Title</ttm:title>
+    <ttm:desc xml:id="description">This example TTML document attempts to use every element.</ttm:desc>
+    <ttm:copyright xml:id="copyright">Never and Anon.</ttm:copyright>
+    <ttm:agent xml:id="connery" type="person">
+      <ttm:name type="full">Sir Thomas Sean Connery</ttm:name>
+    </ttm:agent>
+    <ttm:agent xml:id="bond" type="character">
+      <ttm:name type="alias">007</ttm:name>
+      <ttm:actor agent="connery"/>
+    </ttm:agent>
+    <ttp:profile xml:id="profile" use="dfxp-presentation">
+      <tt:metadata xml:id="m2"/>
+      <ttp:features xml:id="f1set" xml:base="http://www.w3.org/ns/ttml/feature/">
+        <tt:metadata/>
+        <ttp:feature xml:id="f1" value="required">#fontStyle-italic</ttp:feature>
+      </ttp:features>
+      <ttp:extensions xml:id="e1set" xml:base="http://www.w3.org/ns/ttml/extension/">
+        <tt:metadata/>
+        <ttp:extension xml:id="e1" value="required">#smpte-tt-image</ttp:extension>
+      </ttp:extensions>
+    </ttp:profile>
+    <tt:styling>
+      <tt:metadata xml:id="m3"/>
+      <tt:style xml:id="s1" tts:color="red"/>
+    </tt:styling>
+    <tt:layout>
+      <tt:metadata xml:id="m4"/>
+      <tt:region xml:id="r1" style="s1">
+        <tt:metadata xml:id="m5"/>
+        <tt:set xml:id="a1" tts:zIndex="-1"/>
+        <tt:style xml:id="s2" tts:color="green"/>
+      </tt:region>
+    </tt:layout>
+  </tt:head>
+  <tt:body region="r1">
+    <tt:metadata xml:id="m6"/>
+    <tt:set xml:id="a2" tts:display="auto"/>
+    <tt:div>
+      <tt:metadata xml:id="m7"/>
+      <tt:set xml:id="a3" tts:writingMode="tb"/>
+      <tt:p ttm:agent="bond" ttm:role="caption x-extension-role-1">
+        <tt:metadata xml:id="m8"/>
+        <tt:set xml:id="a4" tts:visibility="hidden"/>
+        <tt:span><tt:metadata xml:id="m9"/><tt:set xml:id="a5" tts:fontSize="20px"/>Text 1</tt:span>
+        <tt:br><tt:metadata xml:id="m10"/><tt:set xml:id="a6" tts:display="none"/></tt:br>
+        <tt:span><tt:metadata xml:id="m11"/>Text 2</tt:span>
+      </tt:p>
+    </tt:div>
+  </tt:body>
+</tt:tt>
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/ttml11/spec/examples/ex3-all-styles.xml	Tue Jul 09 14:39:28 2013 -0600
@@ -0,0 +1,363 @@
+<tt tts:extent="640px 480px" xml:lang="en" xmlns="http://www.w3.org/ns/ttml" xmlns:tts="http://www.w3.org/ns/ttml#styling">
+  <head>
+    <layout>
+      <region xml:id="r1">
+        <!-- legal backgroundColor values (not exhaustive) -->
+        <style tts:backgroundColor="#000000"/>
+        <style tts:backgroundColor="#c0c0c0"/>
+        <style tts:backgroundColor="#808080"/>
+        <style tts:backgroundColor="#ffffff"/>
+        <style tts:backgroundColor="#800000"/>
+        <style tts:backgroundColor="#ff0000"/>
+        <style tts:backgroundColor="#800080"/>
+        <style tts:backgroundColor="#ff00ff"/>
+        <style tts:backgroundColor="#008000"/>
+        <style tts:backgroundColor="#00ff00"/>
+        <style tts:backgroundColor="#808000"/>
+        <style tts:backgroundColor="#ffff00"/>
+        <style tts:backgroundColor="#000080"/>
+        <style tts:backgroundColor="#0000ff"/>
+        <style tts:backgroundColor="#008080"/>
+        <style tts:backgroundColor="#00ffff"/>
+        <style tts:backgroundColor="#00000000"/>
+        <style tts:backgroundColor="#000000ff"/>
+        <style tts:backgroundColor="#c0c0c0ff"/>
+        <style tts:backgroundColor="#808080ff"/>
+        <style tts:backgroundColor="#ffffffff"/>
+        <style tts:backgroundColor="#800000ff"/>
+        <style tts:backgroundColor="#ff0000ff"/>
+        <style tts:backgroundColor="#800080ff"/>
+        <style tts:backgroundColor="#ff00ffff"/>
+        <style tts:backgroundColor="#008000ff"/>
+        <style tts:backgroundColor="#00ff00ff"/>
+        <style tts:backgroundColor="#808000ff"/>
+        <style tts:backgroundColor="#ffff00ff"/>
+        <style tts:backgroundColor="#000080ff"/>
+        <style tts:backgroundColor="#0000ffff"/>
+        <style tts:backgroundColor="#008080ff"/>
+        <style tts:backgroundColor="#00ffffff"/>
+        <style tts:backgroundColor="rgb(0,0,0)"/>
+        <style tts:backgroundColor="rgb(192,192,192)"/>
+        <style tts:backgroundColor="rgb(128,128,128)"/>
+        <style tts:backgroundColor="rgb(255,255,255)"/>
+        <style tts:backgroundColor="rgb(128,0,0)"/>
+        <style tts:backgroundColor="rgb(255,0,0)"/>
+        <style tts:backgroundColor="rgb(128,0,128)"/>
+        <style tts:backgroundColor="rgb(255,0,255)"/>
+        <style tts:backgroundColor="rgb(255,0,255)"/>
+        <style tts:backgroundColor="rgb(0,128,0)"/>
+        <style tts:backgroundColor="rgb(0,255,0)"/>
+        <style tts:backgroundColor="rgb(128,128,0)"/>
+        <style tts:backgroundColor="rgb(255,255,0)"/>
+        <style tts:backgroundColor="rgb(0,0,128)"/>
+        <style tts:backgroundColor="rgb(0,0,255)"/>
+        <style tts:backgroundColor="rgb(0,128,128)"/>
+        <style tts:backgroundColor="rgb(0,255,255)"/>
+        <style tts:backgroundColor="rgb(0,255,255)"/>
+        <style tts:backgroundColor="rgba(0,0,0,0)"/>
+        <style tts:backgroundColor="rgba(0,0,0,255)"/>
+        <style tts:backgroundColor="rgba(192,192,192,255)"/>
+        <style tts:backgroundColor="rgba(128,128,128,255)"/>
+        <style tts:backgroundColor="rgba(255,255,255,255)"/>
+        <style tts:backgroundColor="rgba(128,0,0,255)"/>
+        <style tts:backgroundColor="rgba(255,0,0,255)"/>
+        <style tts:backgroundColor="rgba(128,0,128,255)"/>
+        <style tts:backgroundColor="rgba(255,0,255,255)"/>
+        <style tts:backgroundColor="rgba(255,0,255,255)"/>
+        <style tts:backgroundColor="rgba(0,128,0,255)"/>
+        <style tts:backgroundColor="rgba(0,255,0,255)"/>
+        <style tts:backgroundColor="rgba(128,128,0,255)"/>
+        <style tts:backgroundColor="rgba(255,255,0,255)"/>
+        <style tts:backgroundColor="rgba(0,0,128,255)"/>
+        <style tts:backgroundColor="rgba(0,0,255,255)"/>
+        <style tts:backgroundColor="rgba(0,128,128,255)"/>
+        <style tts:backgroundColor="rgba(0,255,255,255)"/>
+        <style tts:backgroundColor="rgba(0,255,255,255)"/>
+        <style tts:backgroundColor="transparent"/>
+        <style tts:backgroundColor="black"/>
+        <style tts:backgroundColor="silver"/>
+        <style tts:backgroundColor="gray"/>
+        <style tts:backgroundColor="white"/>
+        <style tts:backgroundColor="maroon"/>
+        <style tts:backgroundColor="red"/>
+        <style tts:backgroundColor="purple"/>
+        <style tts:backgroundColor="fuchsia"/>
+        <style tts:backgroundColor="magenta"/>
+        <style tts:backgroundColor="green"/>
+        <style tts:backgroundColor="lime"/>
+        <style tts:backgroundColor="olive"/>
+        <style tts:backgroundColor="yellow"/>
+        <style tts:backgroundColor="navy"/>
+        <style tts:backgroundColor="blue"/>
+        <style tts:backgroundColor="teal"/>
+        <style tts:backgroundColor="aqua"/>
+        <style tts:backgroundColor="cyan"/>
+        <!-- legal color values (not exhaustive) -->
+        <style tts:color="#000000"/>
+        <style tts:color="#c0c0c0"/>
+        <style tts:color="#808080"/>
+        <style tts:color="#ffffff"/>
+        <style tts:color="#800000"/>
+        <style tts:color="#ff0000"/>
+        <style tts:color="#800080"/>
+        <style tts:color="#ff00ff"/>
+        <style tts:color="#008000"/>
+        <style tts:color="#00ff00"/>
+        <style tts:color="#808000"/>
+        <style tts:color="#ffff00"/>
+        <style tts:color="#000080"/>
+        <style tts:color="#0000ff"/>
+        <style tts:color="#008080"/>
+        <style tts:color="#00ffff"/>
+        <style tts:color="#00000000"/>
+        <style tts:color="#000000ff"/>
+        <style tts:color="#c0c0c0ff"/>
+        <style tts:color="#808080ff"/>
+        <style tts:color="#ffffffff"/>
+        <style tts:color="#800000ff"/>
+        <style tts:color="#ff0000ff"/>
+        <style tts:color="#800080ff"/>
+        <style tts:color="#ff00ffff"/>
+        <style tts:color="#008000ff"/>
+        <style tts:color="#00ff00ff"/>
+        <style tts:color="#808000ff"/>
+        <style tts:color="#ffff00ff"/>
+        <style tts:color="#000080ff"/>
+        <style tts:color="#0000ffff"/>
+        <style tts:color="#008080ff"/>
+        <style tts:color="#00ffffff"/>
+        <style tts:color="rgb(0,0,0)"/>
+        <style tts:color="rgb(192,192,192)"/>
+        <style tts:color="rgb(128,128,128)"/>
+        <style tts:color="rgb(255,255,255)"/>
+        <style tts:color="rgb(128,0,0)"/>
+        <style tts:color="rgb(255,0,0)"/>
+        <style tts:color="rgb(128,0,128)"/>
+        <style tts:color="rgb(255,0,255)"/>
+        <style tts:color="rgb(255,0,255)"/>
+        <style tts:color="rgb(0,128,0)"/>
+        <style tts:color="rgb(0,255,0)"/>
+        <style tts:color="rgb(128,128,0)"/>
+        <style tts:color="rgb(255,255,0)"/>
+        <style tts:color="rgb(0,0,128)"/>
+        <style tts:color="rgb(0,0,255)"/>
+        <style tts:color="rgb(0,128,128)"/>
+        <style tts:color="rgb(0,255,255)"/>
+        <style tts:color="rgb(0,255,255)"/>
+        <style tts:color="rgba(0,0,0,0)"/>
+        <style tts:color="rgba(0,0,0,255)"/>
+        <style tts:color="rgba(192,192,192,255)"/>
+        <style tts:color="rgba(128,128,128,255)"/>
+        <style tts:color="rgba(255,255,255,255)"/>
+        <style tts:color="rgba(128,0,0,255)"/>
+        <style tts:color="rgba(255,0,0,255)"/>
+        <style tts:color="rgba(128,0,128,255)"/>
+        <style tts:color="rgba(255,0,255,255)"/>
+        <style tts:color="rgba(255,0,255,255)"/>
+        <style tts:color="rgba(0,128,0,255)"/>
+        <style tts:color="rgba(0,255,0,255)"/>
+        <style tts:color="rgba(128,128,0,255)"/>
+        <style tts:color="rgba(255,255,0,255)"/>
+        <style tts:color="rgba(0,0,128,255)"/>
+        <style tts:color="rgba(0,0,255,255)"/>
+        <style tts:color="rgba(0,128,128,255)"/>
+        <style tts:color="rgba(0,255,255,255)"/>
+        <style tts:color="rgba(0,255,255,255)"/>
+        <style tts:color="transparent"/>
+        <style tts:color="black"/>
+        <style tts:color="silver"/>
+        <style tts:color="gray"/>
+        <style tts:color="white"/>
+        <style tts:color="maroon"/>
+        <style tts:color="red"/>
+        <style tts:color="purple"/>
+        <style tts:color="fuchsia"/>
+        <style tts:color="magenta"/>
+        <style tts:color="green"/>
+        <style tts:color="lime"/>
+        <style tts:color="olive"/>
+        <style tts:color="yellow"/>
+        <style tts:color="navy"/>
+        <style tts:color="blue"/>
+        <style tts:color="teal"/>
+        <style tts:color="aqua"/>
+        <style tts:color="cyan"/>
+        <!-- legal direction values -->
+        <style tts:direction="ltr"/>
+        <style tts:direction="rtl"/>
+        <!-- legal display values -->
+        <style tts:display="auto"/>
+        <style tts:display="none"/>
+        <!-- legal displayAlign values -->
+        <style tts:displayAlign="before"/>
+        <style tts:displayAlign="center"/>
+        <style tts:displayAlign="after"/>
+        <!-- legal extent values (not exhaustive) -->
+        <style tts:extent="auto"/>
+        <style tts:extent="620px 96px"/>
+        <!-- legal fontFamily values (not exhaustive) -->
+        <style tts:fontFamily="default"/>
+        <style tts:fontFamily="monospace"/>
+        <style tts:fontFamily="sansSerif"/>
+        <style tts:fontFamily="serif"/>
+        <style tts:fontFamily="monospaceSansSerif"/>
+        <style tts:fontFamily="monospaceSerif"/>
+        <style tts:fontFamily="proportionalSansSerif"/>
+        <style tts:fontFamily="proportionalSerif"/>
+        <style tts:fontFamily="Courier New"/>
+        <style tts:fontFamily="'Courier New'"/>
+        <style tts:fontFamily="default, Courier New"/>
+        <style tts:fontFamily="default, 'Courier New'"/>
+        <style tts:fontFamily="Courier New, default"/>
+        <style tts:fontFamily="'Courier New', default"/>
+        <!-- legal fontSize values (not exhaustive) -->
+        <style tts:fontSize="1c"/>
+        <style tts:fontSize="40px"/>
+        <style tts:fontSize="40px 50px"/>
+        <style tts:fontSize="40px 1c"/>
+        <!-- legal fontStyle values -->
+        <style tts:fontStyle="normal"/>
+        <style tts:fontStyle="italic"/>
+        <style tts:fontStyle="oblique"/>
+        <!-- legal fontWeight values -->
+        <style tts:fontWeight="normal"/>
+        <style tts:fontWeight="bold"/>
+        <!-- legal lineHeight values (not exhaustive) -->
+        <style tts:lineHeight="normal"/>
+        <style tts:lineHeight="1c"/>
+        <style tts:lineHeight="40px"/>
+        <!-- legal opacity values (not exhaustive) -->
+        <style tts:opacity="0"/>
+        <style tts:opacity="0.5"/>
+        <style tts:opacity="1"/>
+        <!-- legal origin values (not exhaustive) -->
+        <style tts:origin="auto"/>
+        <style tts:origin="10px 100px"/>
+        <style tts:origin="1c 10c"/>
+        <style tts:origin="40px 10c"/>
+        <!-- legal overflow values -->
+        <style tts:overflow="visible"/>
+        <style tts:overflow="hidden"/>
+        <!-- legal padding values (not exhaustive) -->
+        <style tts:padding="1px"/>
+        <style tts:padding="1px 2px"/>
+        <style tts:padding="1px 2px 3px"/>
+        <style tts:padding="1px 2px 3px 4px"/>
+        <!-- legal showBackground values -->
+        <style tts:showBackground="always"/>
+        <style tts:showBackground="whenActive"/>
+        <!-- legal textAlign values -->
+        <style tts:textAlign="left"/>
+        <style tts:textAlign="center"/>
+        <style tts:textAlign="right"/>
+        <style tts:textAlign="start"/>
+        <style tts:textAlign="end"/>
+        <!-- legal textDecoration values -->
+        <style tts:textDecoration="none"/>
+        <style tts:textDecoration="underline"/>
+        <style tts:textDecoration="noUnderline"/>
+        <style tts:textDecoration="lineThrough"/>
+        <style tts:textDecoration="noLineThrough"/>
+        <style tts:textDecoration="overline"/>
+        <style tts:textDecoration="noOverline"/>
+        <style tts:textDecoration="noUnderline noLineThrough"/>
+        <style tts:textDecoration="noLineThrough noUnderline"/>
+        <style tts:textDecoration="noUnderline lineThrough"/>
+        <style tts:textDecoration="lineThrough noUnderline"/>
+        <style tts:textDecoration="underline noLineThrough"/>
+        <style tts:textDecoration="noLineThrough underline"/>
+        <style tts:textDecoration="underline lineThrough"/>
+        <style tts:textDecoration="lineThrough underline"/>
+        <style tts:textDecoration="noUnderline noOverline"/>
+        <style tts:textDecoration="noOverline noUnderline"/>
+        <style tts:textDecoration="noUnderline overline"/>
+        <style tts:textDecoration="overline noUnderline"/>
+        <style tts:textDecoration="underline noOverline"/>
+        <style tts:textDecoration="noOverline underline"/>
+        <style tts:textDecoration="underline overline"/>
+        <style tts:textDecoration="overline underline"/>
+        <style tts:textDecoration="noUnderline noLineThrough noOverline"/>
+        <style tts:textDecoration="noUnderline noOverline noLineThrough"/>
+        <style tts:textDecoration="noLineThrough noUnderline noOverline"/>
+        <style tts:textDecoration="noLineThrough noOverline noUnderline"/>
+        <style tts:textDecoration="noOverline noUnderline noLineThrough"/>
+        <style tts:textDecoration="noOverline noLineThrough noUnderline"/>
+        <style tts:textDecoration="noUnderline noLineThrough overline"/>
+        <style tts:textDecoration="noUnderline overline noLineThrough"/>
+        <style tts:textDecoration="noLineThrough noUnderline overline"/>
+        <style tts:textDecoration="noLineThrough overline noUnderline"/>
+        <style tts:textDecoration="overline noUnderline noLineThrough"/>
+        <style tts:textDecoration="overline noLineThrough noUnderline"/>
+        <style tts:textDecoration="noUnderline lineThrough noOverline"/>
+        <style tts:textDecoration="noUnderline noOverline lineThrough"/>
+        <style tts:textDecoration="lineThrough noUnderline noOverline"/>
+        <style tts:textDecoration="lineThrough noOverline noUnderline"/>
+        <style tts:textDecoration="noOverline noUnderline lineThrough"/>
+        <style tts:textDecoration="noOverline lineThrough noUnderline"/>
+        <style tts:textDecoration="noUnderline lineThrough overline"/>
+        <style tts:textDecoration="noUnderline overline lineThrough"/>
+        <style tts:textDecoration="lineThrough noUnderline overline"/>
+        <style tts:textDecoration="lineThrough overline noUnderline"/>
+        <style tts:textDecoration="overline noUnderline lineThrough"/>
+        <style tts:textDecoration="overline lineThrough noUnderline"/>
+        <style tts:textDecoration="underline noLineThrough noOverline"/>
+        <style tts:textDecoration="underline noOverline noLineThrough"/>
+        <style tts:textDecoration="noLineThrough underline noOverline"/>
+        <style tts:textDecoration="noLineThrough noOverline underline"/>
+        <style tts:textDecoration="noOverline underline noLineThrough"/>
+        <style tts:textDecoration="noOverline noLineThrough underline"/>
+        <style tts:textDecoration="underline noLineThrough overline"/>
+        <style tts:textDecoration="underline overline noLineThrough"/>
+        <style tts:textDecoration="noLineThrough underline overline"/>
+        <style tts:textDecoration="noLineThrough overline underline"/>
+        <style tts:textDecoration="overline underline noLineThrough"/>
+        <style tts:textDecoration="overline noLineThrough underline"/>
+        <style tts:textDecoration="underline lineThrough noOverline"/>
+        <style tts:textDecoration="underline noOverline lineThrough"/>
+        <style tts:textDecoration="lineThrough underline noOverline"/>
+        <style tts:textDecoration="lineThrough noOverline underline"/>
+        <style tts:textDecoration="noOverline underline lineThrough"/>
+        <style tts:textDecoration="noOverline lineThrough underline"/>
+        <style tts:textDecoration="underline lineThrough overline"/>
+        <style tts:textDecoration="underline overline lineThrough"/>
+        <style tts:textDecoration="lineThrough underline overline"/>
+        <style tts:textDecoration="lineThrough overline underline"/>
+        <style tts:textDecoration="overline underline lineThrough"/>
+        <style tts:textDecoration="overline lineThrough underline"/>
+        <!-- legal textOutline values (not exhaustive) -->
+        <style tts:textOutline="yellow 1px"/>
+        <style tts:textOutline="yellow 1px 2px"/>
+        <style tts:textOutline="1px"/>
+        <style tts:textOutline="1px 2px"/>
+        <!-- legal unicodeBidi values -->
+        <style tts:unicodeBidi="normal"/>
+        <style tts:unicodeBidi="embed"/>
+        <style tts:unicodeBidi="bidiOverride"/>
+        <!-- legal visibility values -->
+        <style tts:visibility="visible"/>
+        <style tts:visibility="hidden"/>
+        <!-- legal wrapOption values -->
+        <style tts:wrapOption="wrap"/>
+        <style tts:wrapOption="noWrap"/>
+        <!-- legal writingMode values -->
+        <style tts:writingMode="lrtb"/>
+        <style tts:writingMode="rltb"/>
+        <style tts:writingMode="tbrl"/>
+        <style tts:writingMode="tblr"/>
+        <style tts:writingMode="lr"/>
+        <style tts:writingMode="rl"/>
+        <style tts:writingMode="tb"/>
+        <!-- legal zIndex values (not exhaustive) -->
+        <style tts:zIndex="auto"/>
+        <style tts:zIndex="-1"/>
+        <style tts:zIndex="0"/>
+        <style tts:zIndex="1"/>
+      </region>
+    </layout>
+  </head>
+  <body region="r1">
+    <div>
+      <p>Text 1</p>
+    </div>
+  </body>
+</tt>
--- a/ttml11/spec/generate-acknowledgements.xsl	Tue Jul 09 11:28:27 2013 -0600
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,56 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-
-<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
-  xmlns:html="http://www.w3.org/1999/xhtml"
-  exclude-result-prefixes="html"
-  version="1.0">
-
-  <xsl:output
-    method="text"
-    indent="yes"
-    encoding="utf-8"
-    />
-
-  <xsl:param name="participating" />
-
-  <xsl:template match="/">
-    <xsl:call-template name="list-participants">
-      <xsl:with-param name="participating" select="$participating"/>
-    </xsl:call-template>
-  </xsl:template>
-
-  <xsl:template match="html:tr">
-      <xsl:value-of select="html:th[@class='name']/html:a"/>
-      <xsl:text> (</xsl:text>
-      <xsl:value-of select="html:td[@class='orgname']"/>
-      <xsl:text>)</xsl:text>
-  </xsl:template>
-
-  <xsl:template name="list-participants">
-    <xsl:param name="participating"/>
-    <xsl:variable name="status">
-      <xsl:choose>
-	<xsl:when test="$participating = 1">
-	  <xsl:text>good standing</xsl:text>
-	</xsl:when>
-	<xsl:otherwise>
-	  <xsl:text>no longer participating</xsl:text>	  
-	</xsl:otherwise>
-      </xsl:choose>
-    </xsl:variable>
-    <xsl:for-each select="//html:dl[contains(@class, 'group-member')
-			  and contains(normalize-space(html:dd[@class='status']), $status)]">
-      <xsl:value-of select="html:dt[@class='foaf-name']"/>
-      <xsl:if test="$participating = 1"><xsl:text> (</xsl:text>
-      <xsl:value-of select="html:dd[@class='orgname']"/>
-      <xsl:text>)</xsl:text></xsl:if>
-      <xsl:if test="position()!=last()">
-	<xsl:text>, </xsl:text>
-      </xsl:if>
-      <xsl:if test="position()=last()">
-	<xsl:text>.</xsl:text>
-      </xsl:if>
-    </xsl:for-each>
-  </xsl:template>
-
-</xsl:stylesheet>
--- a/ttml11/spec/profiles/dfxp-full.xml	Tue Jul 09 11:28:27 2013 -0600
+++ b/ttml11/spec/profiles/dfxp-full.xml	Tue Jul 09 14:39:28 2013 -0600
@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="utf-8"?>
-<!-- this file defines the "dfxp-full" profile of ttaf1-dfxp -->
+<!-- this file defines the "dfxp-full" profile of ttml -->
 <profile xmlns="http://www.w3.org/ns/ttml#parameter">
   <features xml:base="http://www.w3.org/ns/ttml/feature/">
     <!-- required (mandatory) feature support -->
--- a/ttml11/spec/profiles/dfxp-presentation.xml	Tue Jul 09 11:28:27 2013 -0600
+++ b/ttml11/spec/profiles/dfxp-presentation.xml	Tue Jul 09 14:39:28 2013 -0600
@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="utf-8"?>
-<!-- this file defines the "dfxp-presentation" profile of ttaf1-dfxp -->
+<!-- this file defines the "dfxp-presentation" profile of ttml -->
 <profile xmlns="http://www.w3.org/ns/ttml#parameter">
   <features xml:base="http://www.w3.org/ns/ttml/feature/">
     <!-- required (mandatory) feature support -->
--- a/ttml11/spec/profiles/dfxp-transformation.xml	Tue Jul 09 11:28:27 2013 -0600
+++ b/ttml11/spec/profiles/dfxp-transformation.xml	Tue Jul 09 14:39:28 2013 -0600
@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="utf-8"?>
-<!-- this file defines the "dfxp-transformation" profile of ttaf1 -->
+<!-- this file defines the "dfxp-transformation" profile of ttml -->
 <profile xmlns="http://www.w3.org/ns/ttml#parameter">
   <features xml:base="http://www.w3.org/ns/ttml/feature/">
     <!-- required (mandatory) feature support -->
Binary file ttml11/spec/rnc/schema.zip has changed
--- a/ttml11/spec/rnc/ttml11-datatypes.rnc	Tue Jul 09 11:28:27 2013 -0600
+++ b/ttml11/spec/rnc/ttml11-datatypes.rnc	Tue Jul 09 14:39:28 2013 -0600
@@ -3,7 +3,7 @@
 # .......................................................................
 
 TTAF.Alpha.datatype =
-  xsd:float { minInclusive = "0" maxInclusive = "1" }
+  xsd:float
 
 TTAF.Agent.datatype =
   xsd:IDREFS
@@ -72,13 +72,14 @@
   "bold"
 
 TTAF.FrameRate.datatype =
-  xsd:nonNegativeInteger
+  xsd:positiveInteger
 
 TTAF.FrameRateMultiplier.datatype =
   xsd:string { pattern = "\p{Nd}+\s+\p{Nd}+" }
 
 TTAF.LanguageCode.datatype =
-  xsd:NMTOKEN
+  "" |
+  xsd:language
 
 TTAF.LineHeight.datatype =
   string
@@ -121,7 +122,7 @@
   "transcription"
 
 TTAF.Opacity.datatype =
-  string
+  TTAF.Alpha.datatype
 
 TTAF.Origin.datatype =
   string
@@ -140,7 +141,11 @@
   TTAF.URI.datatype
 
 TTAF.Role.datatype =
-  xsd:NMTOKENS
+  list { TTAF.RoleItem.datatype+ }
+
+TTAF.RoleItem.datatype =
+  TTAF.MetadataRoleBaseType.datatype |
+  xsd:NMTOKEN { pattern = "x-\c+" }
 
 TTAF.ShowBackground.datatype =
   "always" |
@@ -160,10 +165,74 @@
   "none" |
   "underline" |
   "noUnderline" |
+  "lineThrough" |
+  "noLineThrough" |
   "overline" |
   "noOverline" |
-  "lineThrough" |
-  "noLineThrough"
+  "noUnderline noLineThrough" |
+  "noLineThrough noUnderline" |
+  "noUnderline lineThrough" |
+  "lineThrough noUnderline" |
+  "underline noLineThrough" |
+  "noLineThrough underline" |
+  "underline lineThrough" |
+  "lineThrough underline" |
+  "noUnderline noOverline" |
+  "noOverline noUnderline" |
+  "noUnderline overline" |
+  "overline noUnderline" |
+  "underline noOverline" |
+  "noOverline underline" |
+  "underline overline" |
+  "overline underline" |
+  "noUnderline noLineThrough noOverline" |
+  "noUnderline noOverline noLineThrough" |
+  "noLineThrough noUnderline noOverline" |
+  "noLineThrough noOverline noUnderline" |
+  "noOverline noUnderline noLineThrough" |
+  "noOverline noLineThrough noUnderline" |
+  "noUnderline noLineThrough overline" |
+  "noUnderline overline noLineThrough" |
+  "noLineThrough noUnderline overline" |
+  "noLineThrough overline noUnderline" |
+  "overline noUnderline noLineThrough" |
+  "overline noLineThrough noUnderline" |
+  "noUnderline lineThrough noOverline" |
+  "noUnderline noOverline lineThrough" |
+  "lineThrough noUnderline noOverline" |
+  "lineThrough noOverline noUnderline" |
+  "noOverline noUnderline lineThrough" |
+  "noOverline lineThrough noUnderline" |
+  "noUnderline lineThrough overline" |
+  "noUnderline overline lineThrough" |
+  "lineThrough noUnderline overline" |
+  "lineThrough overline noUnderline" |
+  "overline noUnderline lineThrough" |
+  "overline lineThrough noUnderline" |
+  "underline noLineThrough noOverline" |
+  "underline noOverline noLineThrough" |
+  "noLineThrough underline noOverline" |
+  "noLineThrough noOverline underline" |
+  "noOverline underline noLineThrough" |
+  "noOverline noLineThrough underline" |
+  "underline noLineThrough overline" |
+  "underline overline noLineThrough" |
+  "noLineThrough underline overline" |
+  "noLineThrough overline underline" |
+  "overline underline noLineThrough" |
+  "overline noLineThrough underline" |
+  "underline lineThrough noOverline" |
+  "underline noOverline lineThrough" |
+  "lineThrough underline noOverline" |
+  "lineThrough noOverline underline" |
+  "noOverline underline lineThrough" |
+  "noOverline lineThrough underline" |
+  "underline lineThrough overline" |
+  "underline overline lineThrough" |
+  "lineThrough underline overline" |
+  "lineThrough overline underline" |
+  "overline underline lineThrough" |
+  "overline lineThrough underline"
 
 TTAF.TextOutline.datatype =
   string
--- a/ttml11/spec/rnc/ttml11-metadata.rnc	Tue Jul 09 11:28:27 2013 -0600
+++ b/ttml11/spec/rnc/ttml11-metadata.rnc	Tue Jul 09 14:39:28 2013 -0600
@@ -20,7 +20,6 @@
 TTAF.External.class =
   element * - ( tt:* | ttm:* ) {
     ( attribute * - ( xml:id ) { text }
-      | text
       | TTAF.External.class
     )*
   }
--- a/ttml11/spec/rnc/ttml11.rnc	Tue Jul 09 11:28:27 2013 -0600
+++ b/ttml11/spec/rnc/ttml11.rnc	Tue Jul 09 14:39:28 2013 -0600
@@ -6,23 +6,23 @@
 default namespace tt = "http://www.w3.org/ns/ttml"
 
 # generic tt modules
-include "ttaf1-dfxp-datatypes.rnc"
-include "ttaf1-dfxp-classes.rnc"
-include "ttaf1-dfxp-core-attribs.rnc"
-include "ttaf1-dfxp-parameter-attribs.rnc"
-include "ttaf1-dfxp-metadata-attribs.rnc"
-include "ttaf1-dfxp-styling-attribs.rnc"
-include "ttaf1-dfxp-timing-attribs.rnc"
-include "ttaf1-dfxp-parameter-items.rnc"
-include "ttaf1-dfxp-parameters.rnc"
-include "ttaf1-dfxp-metadata-items.rnc"
-include "ttaf1-dfxp-metadata.rnc"
-include "ttaf1-dfxp-styling.rnc"
-include "ttaf1-dfxp-animation.rnc"
-include "ttaf1-dfxp-layout.rnc"
-include "ttaf1-dfxp-content.rnc"
-include "ttaf1-dfxp-head.rnc"
-include "ttaf1-dfxp-document.rnc"
+include "ttml11-datatypes.rnc"
+include "ttml11-classes.rnc"
+include "ttml11-core-attribs.rnc"
+include "ttml11-parameter-attribs.rnc"
+include "ttml11-metadata-attribs.rnc"
+include "ttml11-styling-attribs.rnc"
+include "ttml11-timing-attribs.rnc"
+include "ttml11-parameter-items.rnc"
+include "ttml11-parameters.rnc"
+include "ttml11-metadata-items.rnc"
+include "ttml11-metadata.rnc"
+include "ttml11-styling.rnc"
+include "ttml11-animation.rnc"
+include "ttml11-layout.rnc"
+include "ttml11-content.rnc"
+include "ttml11-head.rnc"
+include "ttml11-document.rnc"
 
 start = TTAF.tt | TTAF.parameters.profile
 
--- a/ttml11/spec/scm/.cvsignore	Tue Jul 09 11:28:27 2013 -0600
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,1 +0,0 @@
-*.esc
\ No newline at end of file
--- a/ttml11/spec/scm/adi.scm	Tue Jul 09 11:28:27 2013 -0600
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,124 +0,0 @@
-;;; -*-Scheme-*-
-;;; Package: (dfxp rxi adi)
-
-;
-; DFXP Abstrarct Document Instance Load, Save, Transformer
-;
-
-(declare (usual-integrations))
-
-(define *dfxp-preferred-reverse-bindings*
-  '(("http://www.w3.org/ns/ttml" . "")
-    ("http://www.w3.org/ns/ttml#parameter" . "ttp")
-    ("http://www.w3.org/ns/ttml#style" . "tts")
-    ("http://www.w3.org/ns/ttml#style-extension" . "ttsx")
-    ("http://www.w3.org/ns/ttml#metadata" . "ttm")
-    ("http://www.w3.org/ns/ttml#metadata-extension" . "ttmx")))
-
-(define *dfxp-namespaces-table*
-  (let ((t (make-string-hash-table)))
-    (for-each
-      (lambda (b)
-        (hash-table/put! t (car b) #t))
-      *dfxp-preferred-reverse-bindings*)
-    t))
-
-(define *dfxp-empty-element-types*
-  '(("br" . "http://www.w3.org/ns/ttml")
-    ("metadata" . "http://www.w3.org/ns/ttml")))
-
-(define (in-per-element-namespace? attr)
-  (let* ((name (rxi-attribute/name attr))
-         (namespace (rxi-name/namespace name)))
-    (null? namespace)))
-
-(define (in-dfxp-namespace? name)
-  (hash-table/get *dfxp-namespaces-table* (rxi-name/namespace name) #f))
-
-(define (in-xml-namespace? name)
-  (string=? (rxi-name/namespace name) (car *xml-default-reverse-binding*)))
-
-(define (in-dfxp-or-xml-namespace? name)
-  (or (in-dfxp-namespace? name)
-      (in-xml-namespace? name)))
-
-(define (empty-dfxp-element-type? elt)
-  (let* ((name (rxi-element/name elt))
-         (local (rxi-name/local name))
-         (namespace (rxi-name/namespace name)))
-    (find-matching-item
-      *dfxp-empty-element-types*
-      (lambda (n)
-        (and (string=? local (car n))
-             (string=? namespace (cdr n)))))))
-                        
-(define (only-whitespace-children? elt)
-  (let ((children (rxi-element/children elt)))
-    (not
-      (find-matching-item
-        children
-        (lambda (c)
-          (or (not (string? c))
-              (string-find-next-char-in-set c char-set:not-whitespace)))))))
-
-(define (rxi-document/adi-transform-element elt)
-  ;; prune and transform children
-  (set-rxi-element/children!
-    elt
-    (delete-matching-items
-      (map
-        (lambda (c)
-          (if (string? c)
-              c
-              (if (not (in-dfxp-namespace? (rxi-element/name c)))
-                  '()
-                  (rxi-document/adi-transform-element c))))
-        (rxi-element/children elt))
-      null?))
-  ;; prune remaining children if empty element type and only whitespace remains
-  (if (and (empty-dfxp-element-type? elt)
-           (only-whitespace-children? elt))
-      (set-rxi-element/children! elt '()))
-  ;; prune foreign namespace attributes
-  (set-rxi-element/attributes!
-    elt
-    (delete-matching-items
-      (rxi-element/attributes elt)
-      (lambda (a)
-          (not (or (in-per-element-namespace? a)
-                   (in-dfxp-or-xml-namespace? (rxi-attribute/name a)))))))
-  elt)
-
-(define (rxi-document/adi-transform document)
-  (if (not (null? (rxi-document/annotation document 'adi-transform)))
-      (warn "Document already transformed, ignoring re-transform.")
-      (let ((root (rxi-document/root document)))
-        (set-rxi-document/root! document (rxi-document/adi-transform-element root))
-        (set-rxi-document/annotation! document 'adi-transform #t)))
-  document)
-  
-;
-; Load TT AF document instance from PATHNAME using RXI loader,
-; then transform resulting RXI-DOCUMENT instance to an ADI-DOCUMENT
-; instance.
-;
-(define (adi-document/load pathname)
-  (rxi-document/adi-transform
-    (rxi-document/load pathname)))
-
-;
-; Save ADI-DOCUMENT instance DOCUMENT, which was created by ADI-DOCUMENT/LOAD,
-; to PATHNAME using underlying RXI-DOCUMENT's document serializer,
-; where optional argument OTHER-REVERSE-BINDINGS, if specified, consists
-; of an association list whose keys are namespace URIs and values are the
-; namespace prefixes to use to designate those namespaces.
-;
-; By default the set of refeverse bindings defined by *DFXP-PREFERRED-REVERSE-BINDING*
-; are used when serializaing. However, reverse bindings specified by using
-; OTHER-REVERSE-BINDINGS take precedence, overriding default reverse bindings.
-;
-(define (adi-document/save document pathname #!optional other-reverse-bindings)
-  (rxi-document/save document pathname
-    (if (default-object? other-reverse-bindings)
-        *dfxp-preferred-reverse-bindings*
-        (append other-reverse-bindings *dfxp-preferred-reverse-bindings*))))
--- a/ttml11/spec/scm/compile.scm	Tue Jul 09 11:28:27 2013 -0600
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,12 +0,0 @@
-;;; -*-Scheme-*-
-
-(load-option 'xml)
-(load-option 'cref)
-(with-working-directory-pathname (directory-pathname (current-load-pathname))
-  (lambda ()
-    (compile-file "rxi")
-    (compile-file "adi")
-    (compile-file "tir")
-    (compile-file "fox")
-    (compile-file "dtf")
-    (cref/generate-constructors "dfxp")))
--- a/ttml11/spec/scm/dfxp.pkg	Tue Jul 09 11:28:27 2013 -0600
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,39 +0,0 @@
-;;; -*-Scheme-*-
-
-(define-package (dfxp)
-  (parent()))
-
-(define-package (dfxp rxi)
-  (files "rxi")
-  (parent (dfxp))
-  (export ()
-          rxi-document/load
-          rxi-document/save
-          rxi-document->list))
-
-(define-package (dfxp rxi adi)
-  (files "adi")
-  (parent (dfxp rxi))
-  (export ()
-          rxi-document/adi-transform
-          adi-document/load
-          adi-document/save))
-
-(define-package (dfxp rxi adi tir)
-  (files "tir")
-  (parent (dfxp rxi adi))
-  (export ()
-          adi-document/tir-transform))
-
-(define-package (dfxp rxi adi tir fox)
-  (files "fox")
-  (parent (dfxp rxi adi tir))
-  (export ()
-          adi-document/fox-transform))
-
-(define-package (dfxp rxi adi tir dtf)
-  (files "dtf")
-  (parent (dfxp rxi adi tir))
-  (export ()
-          adi-document/dtf-process))
-
--- a/ttml11/spec/scm/dtf.scm	Tue Jul 09 11:28:27 2013 -0600
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,12 +0,0 @@
-;;; -*-Scheme-*-
-;;; Package: (dfxp rxi adi tir dtf)
-
-;;;; Dynamic Text Flow Processor
-
-(declare (usual-integrations))
-
-;
-; NOT YET IMPLEMENTED - TO BE PROVIDED PRIOR TO PROPOSED RECOMMENDATION PHASE
-;
-
-(define (adi-document/dtf-process document) document)
--- a/ttml11/spec/scm/fox.scm	Tue Jul 09 11:28:27 2013 -0600
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,12 +0,0 @@
-;;; -*-Scheme-*-
-;;; Package: (dfxp rxi adi tir fox)
-
-;;;; Flow Object Transformer
-
-(declare (usual-integrations))
-
-;
-; NOT YET IMPLEMENTED - TO BE PROVIDED PRIOR TO PROPOSED RECOMMENDATION PHASE
-;
-
-(define (adi-document/fox-transform document) document)
--- a/ttml11/spec/scm/load.scm	Tue Jul 09 11:28:27 2013 -0600
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,7 +0,0 @@
-;;; -*-Scheme-*-
-
-(load-option 'xml)
-(with-working-directory-pathname (directory-pathname (current-load-pathname))
-  (lambda ()
-    (package/system-loader "dfxp" '() 'query)))
-(add-subsystem-identification! "DFXP" '(0 8))
--- a/ttml11/spec/scm/rxi.scm	Tue Jul 09 11:28:27 2013 -0600
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,521 +0,0 @@
-;;; -*-Scheme-*-
-;;; Package: (dfxp rxi)
-
-;
-; DFXP Reduced XML Infoset Load, Save, Transformer
-;
-
-(declare (usual-integrations))
-
-;
-; The default reverse binding for the XML namespace is represented
-; by *XML-DEFAULT-REVERSE-BINDING*.
-;
-(define *xml-default-reverse-binding*
-  '("http://www.w3.org/XML/1998/namespace" . "xml"))
-
-;
-; An RXI-BINDINGS structure consists of a BINDINGS slot that contains a
-; stack represented as a list of association lists whose keys are XMLNS name
-; prefixes and whose values are XMLNS namespace URIs. A binding for the
-; "empty" or "null" namespace is designated by a prefix whose value is "".
-;
-(define-structure
-  (rxi-bindings
-    (conc-name rxi-bindings/)
-    (constructor make-rxi-bindings (#!optional bindings)))
-  (bindings '() read-only #f))
-
-;
-; Push a list of NEW bindings onto BINDINGS.
-;
-(define (rxi-bindings/push! bindings new)
-  (set-rxi-bindings/bindings!
-    bindings
-    (cons new (rxi-bindings/bindings bindings))))
-  
-;
-; Pop the list of bindings at the top of BINDINGS.
-;
-(define (rxi-bindings/pop! bindings)
-  (set-rxi-bindings/bindings!
-    bindings
-    (let ((old (rxi-bindings/bindings bindings)))
-      (if (pair? old)
-          (cdr old)
-          '()))))
-  
-;
-; Look up a binding for the designated XMLNS name PREFIX in BINDINGS,
-; returning either an associated XMLNS namespace URI string or '() if
-; not found.
-;
-
-(define (rxi-bindings/lookup bindings prefix)
-  (let find
-      ((bindings (rxi-bindings/bindings bindings)))
-    (cond ((null? bindings)
-           '())
-          (else
-            (let
-                ((b (find-matching-item
-                      (car bindings)
-                      (lambda (b) (string=? (car b) prefix)))))
-              (if (not (false? b))
-                  (cdr b)
-                  (find (cdr bindings))))))))
-
-;
-; Resolve qualified name QNAME to (VALUES LOCAL NSURI) where LOCAL is
-; the local (unqualified) component of QNAME and NSURI is the
-; associated namespace URI or '() if there is no associated namepsace
-; URI, where IS-ATTRIBUTE? indicates whether the QNAME is the name of
-; an attribute or an element.
-;
-; N.B. the lack of a namespace URI is permitted only for unqualified
-; attribute names; all element names must have an associated namespace URI
-; or an error is signaled. This implies that there must exist a binding for
-; the empty (null) namespace prefix when resolving unqualified element
-; names.
-;
-(define (rxi-bindings/resolve bindings qname is-attribute?)
-  (let* ((i (string-find-next-char qname #\:))
-         (pfx (substring qname 0 (if (false? i) 0 i)))
-         (local (string-tail qname (if (false? i) 0 (+ i 1)))))
-    (values
-      local
-      (if (or (> (string-length pfx) 0) (not is-attribute?))
-          (let ((uri (rxi-bindings/lookup bindings pfx)))
-            (or uri
-                (error "unbound XMLNS prefix on prefix" pfx)))
-          '()))))
-    
-;
-; An RXI-NAME structure represents the name and namespace properties of a
-; reduced XML infoset element or attribute information item and consists of
-; a local name LOCAL and an associated namespace NAMESPACE, a non-empty
-; string or '(), denoting that the name is not namespace qualified. An
-; RXI-NAME is essentially a representation of an XMLNS "expanded name".
-;
-(define-structure
-  (rxi-name (conc-name rxi-name/))
-  (local "" read-only #t)
-  (namespace '() read-only #t))
-
-;
-; Convert an RXI-NAME instance NAME to a list consisting of its constituent
-; slots.
-;
-(define (rxi-name->list name)
-  (list (rxi-name/local name)
-        (rxi-name/namespace name)))
-
-;
-; Transform an XML name IQNAME as defined by the XML package as an uninterned
-; symbol to an RXI-NAME, resolving qualified names into their XMLNS
-; "expanded name" form, where IS-ATTRIBUTE? indicates whether the QNAME is
-; the name of an attribute or an element.
-;
-(define (rxi-name/transform-from-xml iqname is-attribute? bindings)
-  (call-with-values
-    (lambda ()
-      (rxi-bindings/resolve bindings (symbol-name iqname) is-attribute?))
-    make-rxi-name))
-
-;
-; An RXI-ATTRIBUTE structure represents a reduced XML infoset attribute
-; information item and consists of a NAME represented as an RXI-NAME
-; instance and a VALUE represented as a string.
-;
-(define-structure
-  (rxi-attribute (conc-name rxi-attribute/))
-  (name '() read-only #t)
-  (value "" read-only #t))
-
-;
-; Convert an RXI-ATTRIBUTE instance ATTRIBUTE to a list consisting of its
-; constituent slots.
-;
-(define (rxi-attribute->list attribute)
-  (list (rxi-name->list (rxi-attribute/name attribute))
-        (rxi-attribute/value attribute)))
-
-;
-; Transform XML-ATTRIBUTE instance ATTRIBUTE to RXI-ATTRIBUTE instance,
-; where BINDINGS is the current bindings stack.
-;
-(define (rxi-attribute/transform-from-xml attribute bindings)
-  (let ((n (car attribute)) (v (cdr attribute)))
-    (make-rxi-attribute (rxi-name/transform-from-xml n #t bindings) v)))
-
-;
-; An RXI-ELEMENT structure represents a reduced XML infoset element
-; information item and consists of a NAME represented as an RXI-NAME
-; instance, a possibly empty set of ATTRIBUTES represented as a list of
-; RXI-ATTRIBUTE instances, and a possibly empty set of CHILDREN represented
-; as a list of string or RXI-ELEMENT instances.
-;
-(define-structure
-  (rxi-element (conc-name rxi-element/))
-  (name "" read-only #t)
-  (attributes '() read-only #f)
-  (children '() read-only #f))
-
-;
-; Convert an RXI-ELEMENT instance ELEMENT to a list consisting of its
-; constituent slots.
-;
-(define (rxi-element->list element)
-  (list (rxi-name->list (rxi-element/name element))
-        (map
-          rxi-attribute->list
-          (rxi-element/attributes element))
-        (map
-          (lambda (c)
-            (if (string? c)
-                c
-                (rxi-element->list c)))
-          (rxi-element/children element))))
-
-;
-; Determine if XML-ATTRIBUTE instance ATTRIBUTE, represented as a pair
-; (NAME . VALUE), is an XMLNS attribute or not, i.e., has a qualified name
-; whose prefix is "xmlns" or is the unqualified name "xmlns".
-;
-(define (namespace-attribute? attribute)
-  (let ((qname (symbol-name (car attribute))))
-    (and (string-prefix? "xmlns" qname)
-         (or (= (string-length qname) 5)
-             (let ((i (string-find-next-char qname #\:)))
-               (and (not (false? i)) (= i 5)))))))
-
-;
-; Given a list ATTRIBUTES of XML-ATTRIBUTE instances consisting only of
-; XMLNS attributes as determined by NAMESPACE-ATTRIBUTE? above, return a set
-; of bindings as an association list whose keys are namespace prefixes and
-; whose values are the associated namespace URIs.
-;
-(define (extract-namespace-bindings attributes)
-  (map
-    (lambda (a)
-      (let ((qname (symbol-name (car a))))
-        (if (= (string-match-forward qname "xmlns") 5)
-            (cons
-             (if (>= (string-length qname) 6)
-                 (string-tail qname 6)
-                 "")
-             (cdr a))
-            (error "Invalid namespace attribute" qname))))
-    attributes))
-
-;
-; Transform XML-ELEMENT instance ELEMENT to RXI-ELEMENT instance,
-; where BINDINGS is the current bindings stack.
-;
-(define (rxi-element/transform-from-xml element bindings)
-  (let* ((attributes
-           (xml-element-attributes element))
-         (ns-attributes
-           (keep-matching-items attributes namespace-attribute?))
-         (other-attributes
-           (keep-matching-items
-             attributes
-             (lambda (a) (not (namespace-attribute? a))))))
-    (rxi-bindings/push! bindings (extract-namespace-bindings ns-attributes))
-    (let ((rxi-element
-            (make-rxi-element
-              (rxi-name/transform-from-xml
-                (xml-element-name element) #f bindings)
-              (map
-                (lambda (a) (rxi-attribute/transform-from-xml a bindings))
-                other-attributes)
-              (map
-                (lambda (c)
-                  (if (string? c)
-                      c
-                      (rxi-element/transform-from-xml c bindings)))
-                (xml-element-contents element)))))
-      (rxi-bindings/pop! bindings)
-      rxi-element)))
-
-;
-; An RXI-DOCUMENT structure represents a reduced XML infoset document
-; information item and consists of an ANNOTATIONS association list, used for
-; internal book-keeping purposes, and an RXI-ELEMENT instance representing
-; the document's root element or '() if there is no root element.
-;
-(define-structure
-  (rxi-document (conc-name rxi-document/))
-  (annotations '() read-only #f)
-  (root '() read-only #f))
-
-;
-; Look up value of annotation named KEY on RXI-DOCUMENT instance DOCUMENT.
-;
-(define (rxi-document/annotation document key)
-  (assq key (rxi-document/annotations document)))
-
-;
-; Add annotation (KEY . VALUE) to RXI-DOCUMENT instance DOCUMENT.
-;
-(define (set-rxi-document/annotation! document key value)
-  (set-rxi-document/annotations! document (cons (cons key value) (rxi-document/annotations document))))
-
-;
-; Remove all annotations named KEY from RXI-DOCUMENT instance DOCUMENT.
-;
-(define (rxi-document/remove-annotation! document key)
-  (del-assq! key (rxi-document/annotations document)))
-
-;
-; Convert an RXI-DOCUMENT instance DOCUMENT to a list consisting of its
-; constituent slots.
-;
-(define (rxi-document->list document)
-  (list (rxi-document/annotations document)
-        (rxi-element->list (rxi-document/root document))))
-
-;
-; Transform XML-DOCUMENT instance DOCUMENT to RXI-DOCUMENT instance.
-;
-(define (rxi-document/transform-from-xml document)
-  (let
-    ((bindings
-      (make-rxi-bindings
-        (list (list (cons (cdr *xml-default-reverse-binding*)
-                          (car *xml-default-reverse-binding*)))))))
-    (make-rxi-document
-      '()
-      (rxi-element/transform-from-xml (xml-document-root document) bindings))))
-
-;
-; Load XML document instance from PATHNAME using XML package's XML parser,
-; then transform resulting XML-DOCUMENT instance to an RXI-DOCUMENT
-; instance.
-;
-(define (rxi-document/load pathname)
-  (rxi-document/transform-from-xml
-    (call-with-input-file pathname
-      (lambda (port)
-        (parse-xml-document (input-port->parser-buffer port))))))
-
-;
-; An RXI-REVERSE-BINDINGS structure consists of a REVERSE-BINDINGS slot
-; that contains an association list whose keys are XMLNS namespace URIs and
-; whose values are XMLNS name prefixes. The URI component of a reverse
-; binding entry MUST be a non-empty string.
-;
-(define-structure
-  (rxi-reverse-bindings
-    (conc-name rxi-reverse-bindings/)
-    (constructor make-rxi-reverse-bindings (#!optional reverse-bindings)))
-  (reverse-bindings '() read-only #f))
-
-(define (rxi-reverse-bindings/lookup reverse-bindings uri)
-  (if (and (string? uri)
-           (not (string-null? uri)))
-      (let find
-          ((rb (rxi-reverse-bindings/reverse-bindings reverse-bindings)))
-        (cond ((null? rb)
-               '())
-              (else
-               (let
-                   ((b (car rb)))
-                 (if (string=? (car b) uri)
-                     (cdr b)
-                     (find (cdr rb)))))))
-      (error "non-string or empty XMLNS namespace URI" uri)))
-
-(define (rxi-reverse-bindings/generate-prefix reverse-bindings)
-  (let ((g (lambda () (string-downcase (symbol-name (generate-uninterned-symbol)))))
-        (rb (rxi-reverse-bindings/reverse-bindings reverse-bindings)))
-    (let loop
-        ((pfx '()))
-      (cond ((null? pfx)
-             (loop (g)))
-            (else
-             (if (not (find-matching-item
-                        rb
-                        (lambda (b)
-                          (and (string? (cdr b)) (string=? (cdr b) pfx)))))
-                 pfx
-                 (loop (g))))))))
-
-(define (rxi-reverse-bindings/add! reverse-bindings uri pfx)
-  (set-rxi-reverse-bindings/reverse-bindings!
-    reverse-bindings
-    (cons (cons uri pfx) (rxi-reverse-bindings/reverse-bindings reverse-bindings))))
-  
-(define (rxi-reverse-bindings/sort! reverse-bindings)
-  (let
-      ((rb (rxi-reverse-bindings/reverse-bindings reverse-bindings)))
-    (set-rxi-reverse-bindings/reverse-bindings!
-      reverse-bindings
-      (sort rb
-            (lambda (x y)
-              (string<? (cdr x) (cdr y)))))))
-
-(define (rxi-reverse-bindings/normalize-preferred preferred-reverse-bindings)
-  (let ((rbt (make-string-hash-table (length preferred-reverse-bindings)))
-        (xrb *xml-default-reverse-binding*))
-    (let loop
-        ((prb preferred-reverse-bindings))
-      (cond ((null? prb)
-             (if (not (hash-table/get rbt (car xrb) #f))
-                 (hash-table/put! rbt (car xrb) (cdr xrb)))
-             (hash-table->alist rbt))
-            (else
-             (let ((b (car prb)))
-               (if (not (pair? b))
-                   (error "preferred reverse binding not a pair" b)
-                   (let ((u (car b))
-                         (p (cdr b)))
-                     (if (not (hash-table/get rbt u #f))
-                         (hash-table/put! rbt u p))
-                     (loop (cdr prb))))))))))
-
-;
-; Transform an RXI-NAME instance NAME to an XML name IQNAME as defined by the
-; XML package as an uninterned symbol, where IS-ATTRIBUTE? indicates whether
-; the IQNAME is the name of an attribute or an element, and where REVERSE-BINDINGS
-; is the current reverse bindings.
-;
-(define (rxi-name/transform-to-xml name is-attribute? reverse-bindings)
-  (let ((uri (rxi-name/namespace name))
-        (loc (rxi-name/local name)))
-    (xml-intern
-      (if (null? uri)
-          loc
-          (let ((pfx (rxi-reverse-bindings/lookup reverse-bindings uri)))
-            (if (string-null? pfx)
-                loc
-                (string-append
-                  pfx
-                  (string-append ":" loc))))))))
-  
-;
-; Transform RXI-ATTRIBUTE instance ATTRIBUTE to XML-ATTRIBUTE instance.
-;
-(define (rxi-attribute/transform-to-xml attribute reverse-bindings)
-  (cons
-    (rxi-name/transform-to-xml (rxi-attribute/name attribute) #t reverse-bindings)
-    (rxi-attribute/value attribute)))
-
-(define (maybe-add-reverse-binding! reverse-bindings name)
-  (let ((uri (rxi-name/namespace name)))
-    (if (not (null? uri))
-        (if (not (rxi-reverse-bindings/lookup reverse-bindings uri))
-            (rxi-reverse-bindings/add! reverse-bindings uri (rxi-reverse-bindings/generate-prefix reverse-bindings))))))
-
-(define (rxi-element/collect-reverse-bindings element reverse-bindings)
-  ;; collect element's binding
-  (maybe-add-reverse-binding! reverse-bindings (rxi-element/name element))
-  ;; collect attribute reverse-bindings
-  (let ((attributes (rxi-element/attributes element)))
-    (for-each
-      (lambda (a)
-        (maybe-add-reverse-binding! reverse-bindings (rxi-attribute/name a)))
-      attributes))
-  ;; collect childrens' reverse bindings
-  (let ((children (rxi-element/children element)))
-    (for-each 
-      (lambda (c)
-        (if (not (string? c))
-            (rxi-element/collect-reverse-bindings c reverse-bindings)))
-      children)))
-
-;
-; Transform RXI-ELEMENT instance ELEMENT to XML-ELEMENT instance.
-;
-(define (rxi-element/transform-to-xml element reverse-bindings)
-  (make-xml-element
-    (rxi-name/transform-to-xml (rxi-element/name element) #f reverse-bindings)
-    (map
-      (lambda (a)
-        (rxi-attribute/transform-to-xml a reverse-bindings))
-      (rxi-element/attributes element))
-    (map
-      (lambda (c)
-        (if (string? c)
-            c
-            (rxi-element/transform-to-xml c reverse-bindings)))
-      (rxi-element/children element))))
-
-;
-; Add XMLNS attributes that correspond with REVERSE-BINDINGS to the root
-; element of XML-DOCUMENT instance DOCUMENT. If DOCUMENT has no root
-; element, then do nothing.
-;
-(define (xml-document-add-bindings! document reverse-bindings)
-  (let ((root (xml-document-root document)))
-    (if (not (null? root))
-        (set-xml-element-attributes!
-          root
-          (append
-            (xml-element-attributes root)
-            (map
-              (lambda (b)
-                (let*
-                    ((prefix (cdr b))
-                     (ns-attr-name
-                       (if (string-null? prefix)
-                           "xmlns"
-                           (string-append "xmlns:" prefix))))
-                  (cons (xml-intern ns-attr-name) (car b))))
-              (rxi-reverse-bindings/reverse-bindings reverse-bindings)))))))
-  
-;
-; Collect 
-;
-(define (rxi-document/collect-reverse-bindings document reverse-bindings)
-  (let ((root (rxi-document/root document)))
-    (if (not (null? root))
-        (rxi-element/collect-reverse-bindings root reverse-bindings))
-    (rxi-reverse-bindings/sort! reverse-bindings)
-    reverse-bindings))
-
-;
-; Transform RXI-DOCUMENT instance DOCUMENT to XML-DOCUMENT instance.
-;
-(define (rxi-document/transform-to-xml document preferred-reverse-bindings)
-  (let
-      ((reverse-bindings
-         (make-rxi-reverse-bindings
-           (rxi-reverse-bindings/normalize-preferred preferred-reverse-bindings))))
-    (rxi-document/collect-reverse-bindings document reverse-bindings)
-    (let
-        ((xml-document
-          (make-xml-document
-           '()                          ; declaration
-           '()                          ; misc-1
-           '()                          ; dtd
-           '()                          ; misc-2
-           (rxi-element/transform-to-xml
-             (rxi-document/root document) reverse-bindings)
-           '())))                       ; misc-3
-      (xml-document-add-bindings! xml-document reverse-bindings)
-      xml-document)))
-
-;
-; Save RXI-DOCUMENT instance DOCUMENT by transforming to an XML-DOCUMENT
-; instance and serializing to PATHNAME using XML package's document serializer,
-; where optional argument PREFERRED-REVERSE-BINDINGS, if specified, consists
-; of an association list whose keys are namespace URIs and values are the
-; preferred namespace prefixes to use to designate those namespaces.
-;
-; If a namepsace URI appears in DOCUMENT and it has no preferred binding
-; specified, then a prefix is generated unless the namespace URI is
-; "http://www.w3.org/XML/1998/namespace", in which case the prefix "xml" is
-; used.
-;
-(define (rxi-document/save document pathname #!optional preferred-reverse-bindings)
-  (let
-      ((xml-document
-         (rxi-document/transform-to-xml
-          document
-          (if (default-object? preferred-reverse-bindings)
-              '()
-              preferred-reverse-bindings))))
-    (call-with-output-file pathname
-      (lambda (port)
-        (write-xml xml-document port)))))
--- a/ttml11/spec/scm/test.xml	Tue Jul 09 11:28:27 2013 -0600
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,80 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<tt ttp:profile="http://www.w3.org/ns/ttml#profile-dfxp"
-    xml:lang="en"
-    xmlns="http://www.w3.org/ns/ttml"
-    xmlns:ttp="http://www.w3.org/ns/ttml#parameter"
-    xmlns:ttm="http://www.w3.org/ns/ttml#metadata"
-    xmlns:tts="http://www.w3.org/ns/ttml#style">
-  <head>
-    <metadata>
-      <ttm:title>Timed Text DFXP Example</ttm:title>
-      <ttm:copyright>The Authors (c) 2006</ttm:copyright>
-    </metadata>
-    <styling>
-      <!-- s1 specifies default color, font, and text alignment -->
-      <style xml:id="s1"
-        tts:color="white"
-        tts:fontFamily="proportionalSansSerif"
-        tts:fontSize="22px"
-        tts:textAlign="center"
-      />
-      <!-- alternative using yellow text but otherwise the same as style s1 -->
-      <style xml:id="s2" style="s1" tts:color="yellow"/>
-      <!-- a style based on s1 but justified to the right -->
-      <style xml:id="s1Right" style="s1" tts:textAlign="end" />     
-      <!-- a style based on s2 but justified to the left -->
-      <style xml:id="s2Left" style="s2" tts:textAlign="start" />
-    </styling>
-    <layout>
-      <region xml:id="subtitleArea"
-        style="s1"
-        tts:extent="560px 62px"
-        tts:padding="5px 3px"
-        tts:backgroundColor="black"
-        tts:displayAlign="after"
-      />
-    </layout>  
-  </head>
-  <body region="subtitleArea">
-    <div>
-      <p xml:id="subtitle1" begin="0.76s" end="3.45s">
-        It seems a paradox, does it not,
-      </p>
-      <p xml:id="subtitle2" begin="5.0s" end="10.0s">
-        that the image formed on<br/>
-        the Retina should be inverted?
-      </p>
-      <p xml:id="subtitle3" begin="10.0s" end="16.0s" style="s2">
-        It is puzzling, why is it<br/>
-        we do not see things upside-down?
-      </p>
-      <p xml:id="subtitle4" begin="17.2s" end="23.0s">
-        You have never heard the Theory,<br/>
-        then, that the Brain also is inverted?
-      </p>
-      <p xml:id="subtitle5" begin="23.0s" end="27.0s" style="s2">
-        No indeed! What a beautiful fact!
-      </p>
-      <p xml:id="subtitle6a" begin="28.0s" end="34.6s" style="s2Left">
-        But how is it proved?
-      </p>
-      <p xml:id="subtitle6b" begin="28.0s" end="34.6s" style="s1Right">
-        Thus: what we call
-      </p>
-      <p xml:id="subtitle7" begin="34.6s" end="45.0s" style="s1Right">
-        the vertex of the Brain<br/>
-        is really its base
-      </p>
-      <p xml:id="subtitle8" begin="45.0s" end="52.0s" style="s1Right">
-        and what we call its base<br/>
-        is really its vertex,
-      </p>
-      <p xml:id="subtitle9a" begin="53.5s" end="58.7s">
-        it is simply a question of nomenclature.
-      </p>
-      <p xml:id="subtitle9b" begin="53.5s" end="58.7s" style="s2">
-        How truly delightful!
-      </p>
-    </div>    
-  </body>
-</tt>
--- a/ttml11/spec/scm/tir.scm	Tue Jul 09 11:28:27 2013 -0600
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,12 +0,0 @@
-;;; -*-Scheme-*-
-;;; Package: (dfxp rxi adi tir)
-
-;;;; DFXP Timing Interval Resolver
-
-(declare (usual-integrations))
-
-;
-; NOT YET IMPLEMENTED - TO BE PROVIDED PRIOR TO PROPOSED RECOMMENDATION PHASE
-;
-
-(define (adi-document/tir-transform document) document)
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/ttml11/spec/ttml-changes.html	Tue Jul 09 14:39:28 2013 -0600
@@ -0,0 +1,48 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+<head>
+<title>TTML 1.1 - List of changes</title>
+<style type="text/css">
+div.exampleInner pre { margin-left: 1em;
+                       margin-top: 0em; margin-bottom: 0em}
+div.exampleInner { background-color: #d5dee3;
+                   border-top-width: 4px;
+                   border-top-style: double;
+                   border-top-color: #d3d3d3;
+                   border-bottom-width: 4px;
+                   border-bottom-style: double;
+                   border-bottom-color: #d3d3d3;
+                   padding: 4px; margin: 0em }
+.strong { font-weight: bold; }
+</style>
+<link rel="stylesheet" type="text/css" href="http://www.w3.org/StyleSheets/TR/base.css"/>
+</head>
+<body>
+<h1>Timed Text Markup Language (TTML) 1.1 Change Summary</h1>
+<p>1 <a href="#change-history">Change History</a> (Non-Normative)<br/>
+    1.1 <a href="#change-history-ttml10-rec-2e-to-ttml11-fpwd">Draft Changes from Proposed Edited Recommendation (2nd Ed.) to Recommendation (2nd Ed.)</a><br/>
+</p>
+<div class="div1">
+<h2><a id="change-history"/>1 Change History (Non-Normative)</h2>
+<p>Changes are ordered from most recent to least recent.</p>
+
+<div class="div2">
+<h3><a id="change-history-ttml10-rec-2e-to-ttml11-fpwd"/>1.1 Draft Changes from TTML1.0 (2nd Ed.) to TTML1.1 First Public Working Draft</h3>
+<div class="exampleInner">
+<span class="strong">Technical Changes</span>
+
+* 
+
+</pre>
+<pre>
+<span class="strong">Editorial Changes</span>
+
+* 
+
+</pre>
+</div>
+</div>
+</div>
+</body>
+</html>
--- a/ttml11/spec/ttml-issues.html	Tue Jul 09 11:28:27 2013 -0600
+++ b/ttml11/spec/ttml-issues.html	Tue Jul 09 14:39:28 2013 -0600
@@ -4,212 +4,7 @@
 <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 (public-tt@w3.org)</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>
-
+<h1>Timed Text Markup Language (TTML) 1.1: Errata</h1>
+<p>None</p>
 </body>
 </html>
--- a/ttml11/spec/ttml11.xml	Tue Jul 09 11:28:27 2013 -0600
+++ b/ttml11/spec/ttml11.xml	Tue Jul 09 14:39:28 2013 -0600
@@ -1,12974 +1,13566 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<!-- $Id$ -->
-<!DOCTYPE spec PUBLIC "-//W3C//DTD Specification V2.10//EN" "xmlspec-ttml11.dtd" [
-<!ENTITY % entities SYSTEM "entities.dtd" >
-%entities;
-<!ENTITY status SYSTEM "status.xml">
-<!ENTITY document.status "Editors' copy $Date$">
-<!ENTITY title "&title;">
-<!ENTITY prevloc "http://www.w3.org/TR/2010/REC-ttaf1-dfxp-20101118/">
-<!ENTITY versionOfTT "1.0">
-<!ENTITY tbd "<phrase role='tbd'>To Be Defined</phrase>">
-<!ENTITY sp "&#x0020;">
-<!ENTITY sect "&#x00a7;">
-<!ENTITY aring "&#x00e5;">
-<!ENTITY ccedil "&#x00e7;">
-<!ENTITY Ccedil "&#x00c7;">
-<!ENTITY mult "&#x00d7;">
-<!ENTITY uuml "&#x00fc;">
-<!ENTITY nbsp "&#x00a0;">
-<!ENTITY ndash "&#x2013;">
-<!ENTITY mdash "&#x2014;">
-<!ENTITY prime "&#x2032;">
-<!ENTITY hArr "&#x21d4;">
-<!ENTITY trade "&#x2122;">
-<!ENTITY hellip "&#x2026;">
-<!ENTITY isin "&#x2208;">
-<!ENTITY minus "&#x2212;">
-<!ENTITY le "&#x2264;">
-<!ENTITY ge "&#x2265;">
-<!ENTITY plusmn "&#x00B1;">
-<!ENTITY dfxp-ex1 SYSTEM "./examples/ex1.xml.esc">
-<!ENTITY dfxp-ex1-x-0 SYSTEM "./examples/ex1-x-0.xml.esc">
-<!ENTITY dfxp-ex1-p-0 SYSTEM "./examples/ex1-p-0.xml.esc">
-<!ENTITY dfxp-ex1-x-1 SYSTEM "./examples/ex1-x-1.xml.esc">
-<!ENTITY dfxp-ex1-x-2 SYSTEM "./examples/ex1-x-2.xml.esc">
-<!ENTITY rnc-dfxp-driver SYSTEM "./rnc/ttml11.rnc.esc">
-<!ENTITY rnc-dfxp-animation-module SYSTEM "./rnc/ttml11-animation.rnc.esc">
-<!ENTITY rnc-dfxp-classes-module SYSTEM "./rnc/ttml11-classes.rnc.esc">
-<!ENTITY rnc-dfxp-content-module SYSTEM "./rnc/ttml11-content.rnc.esc">
-<!ENTITY rnc-dfxp-core-attribs-module SYSTEM "./rnc/ttml11-core-attribs.rnc.esc">
-<!ENTITY rnc-dfxp-datatypes-module SYSTEM "./rnc/ttml11-datatypes.rnc.esc">
-<!ENTITY rnc-dfxp-document-module SYSTEM "./rnc/ttml11-document.rnc.esc">
-<!ENTITY rnc-dfxp-head-module SYSTEM "./rnc/ttml11-head.rnc.esc">
-<!ENTITY rnc-dfxp-metadata-module SYSTEM "./rnc/ttml11-metadata.rnc.esc">
-<!ENTITY rnc-dfxp-metadata-items-module SYSTEM "./rnc/ttml11-metadata-items.rnc.esc">
-<!ENTITY rnc-dfxp-metadata-attribs-module SYSTEM "./rnc/ttml11-metadata-attribs.rnc.esc">
-<!ENTITY rnc-dfxp-parameters-module SYSTEM "./rnc/ttml11-parameters.rnc.esc">
-<!ENTITY rnc-dfxp-parameter-items-module SYSTEM "./rnc/ttml11-parameter-items.rnc.esc">
-<!ENTITY rnc-dfxp-parameter-attribs-module SYSTEM "./rnc/ttml11-parameter-attribs.rnc.esc">
-<!ENTITY rnc-dfxp-styling-attribs-module SYSTEM "./rnc/ttml11-styling-attribs.rnc.esc">
-<!ENTITY rnc-dfxp-styling-module SYSTEM "./rnc/ttml11-styling.rnc.esc">
-<!ENTITY rnc-dfxp-layout-module SYSTEM "./rnc/ttml11-layout.rnc.esc">
-<!ENTITY rnc-dfxp-timing-attribs-module SYSTEM "./rnc/ttml11-timing-attribs.rnc.esc">
-<!ENTITY xsd-dfxp-driver SYSTEM "./xsd/ttml11.xsd.esc">
-<!ENTITY xsd-dfxp-animation-module SYSTEM "./xsd/ttml11-animation.xsd.esc">
-<!ENTITY xsd-dfxp-content-module SYSTEM "./xsd/ttml11-content.xsd.esc">
-<!ENTITY xsd-dfxp-core-attribs-module SYSTEM "./xsd/ttml11-core-attribs.xsd.esc">
-<!ENTITY xsd-dfxp-datatypes-module SYSTEM "./xsd/ttml11-datatypes.xsd.esc">
-<!ENTITY xsd-dfxp-document-module SYSTEM "./xsd/ttml11-document.xsd.esc">
-<!ENTITY xsd-dfxp-head-module SYSTEM "./xsd/ttml11-head.xsd.esc">
-<!ENTITY xsd-dfxp-metadata-module SYSTEM "./xsd/ttml11-metadata.xsd.esc">
-<!ENTITY xsd-dfxp-metadata-items-module SYSTEM "./xsd/ttml11-metadata-items.xsd.esc">
-<!ENTITY xsd-dfxp-metadata-attribs-module SYSTEM "./xsd/ttml11-metadata-attribs.xsd.esc">
-<!ENTITY xsd-dfxp-parameters-module SYSTEM "./xsd/ttml11-parameters.xsd.esc">
-<!ENTITY xsd-dfxp-parameter-items-module SYSTEM "./xsd/ttml11-parameter-items.xsd.esc">
-<!ENTITY xsd-dfxp-parameter-attribs-module SYSTEM "./xsd/ttml11-parameter-attribs.xsd.esc">
-<!ENTITY xsd-dfxp-styling-attribs-module SYSTEM "./xsd/ttml11-styling-attribs.xsd.esc">
-<!ENTITY xsd-dfxp-styling-module SYSTEM "./xsd/ttml11-styling.xsd.esc">
-<!ENTITY xsd-dfxp-layout-module SYSTEM "./xsd/ttml11-layout.xsd.esc">
-<!ENTITY xsd-dfxp-timing-attribs-module SYSTEM "./xsd/ttml11-timing-attribs.xsd.esc">
-<!ENTITY xsd-dfxp-xml-attrs-module SYSTEM "./xsd/xml.xsd.esc">
-<!ENTITY profile-dfxp-presentation SYSTEM "./profiles/dfxp-presentation.xml.esc">
-<!ENTITY profile-dfxp-transformation SYSTEM "./profiles/dfxp-transformation.xml.esc">
-<!ENTITY profile-dfxp-full SYSTEM "./profiles/dfxp-full.xml.esc">
-]>
-<?xml-stylesheet type='text/xsl' href='xmlspec-ttml11.xsl'?>
-<spec w3c-doctype="&doctype;" role="&document.role;">
-<header>
-<title>&title;</title>
-<w3c-designation>&w3c-designation;</w3c-designation>
-<w3c-doctype>&document.status;</w3c-doctype>
-<pubdate>
-<day>&draft.day;</day>
-<month>&draft.month;</month>
-<year>&draft.year;</year>
-</pubdate>
-<publoc>
-<loc href="&w3c-designation;">&w3c-designation;</loc>
-</publoc>
-<prevlocs>
-<loc href="&prevloc;">&prevloc;</loc>
-</prevlocs>
-<latestloc>
-<loc href="&latest;">&latest;</loc>
-</latestloc>
-<authlist id="editors" role="editor">
-<author>
-<name>Glenn Adams</name>
-<affiliation>Cox Communications, Inc.</affiliation>
-</author>
-</authlist>
-<authlist id="contributors" role="contributor">
-<author>
-<name>Mike Dolan</name>
-<affiliation>Invited Expert</affiliation>
-</author>
-<author>
-<name>Geoff Freed</name>
-<affiliation>WGBH National Center for Accessible Media</affiliation>
-</author>
-<author>
-<name>Sean Hayes</name>
-<affiliation>Microsoft</affiliation>
-</author>
-<author>
-<name>Erik Hodge</name>
-<affiliation>RealNetworks</affiliation>
-</author>
-<author>
-<name>David Kirby</name>
-<affiliation>British Broadcasting Corporation (BBC)</affiliation>
-</author>
-<author>
-<name>Thierry Michel</name>
-<affiliation>W3C</affiliation>
-</author>
-<author>
-<name>Dave Singer</name>
-<affiliation>Apple Computer</affiliation>
-</author>
-</authlist>
-<abstract id="abstract">
-<p>This document specifies the Timed Text Markup Language (TTML) in terms of a
-vocabulary and semantics thereof.</p>
-<p>The Timed Text Markup Language is a content type that represents
-timed text media for the purpose of interchange among authoring
-systems. Timed text is textual information that is intrinsically or
-extrinsically associated with timing information.</p>
-<p>It is intended to be used
-for the purpose of transcoding or exchanging timed text information
-among legacy distribution content formats presently in use for
-subtitling and captioning functions.</p>
-<p>In addition to being used for interchange among legacy distribution content
-formats, TTML content may be used directly as a distribution format,
-for example, providing a standard content format to reference from a <el>&lt;text&gt;</el> or 
-<el>&lt;textstream&gt;</el> media object element in a <bibref
-ref="smil21"/> document.</p>
-</abstract>
-&status;
-<langusage><language id='en-us'>English</language></langusage>
-<revisiondesc><p>Last Modified: $Date$</p></revisiondesc>
-</header>
-<body>
-<div1 id="intro">
-<head>Introduction</head>
-<p><emph>Unless specified otherwise, this section and its sub-sections are non-normative.</emph></p>
-<p>The Timed Text Markup Language (TTML) 1.0
-provides a standardized representation of a particular subset of
-textual information with which stylistic, layout, and timing semantics are associated by
-an author or an authoring system for the purpose of interchange and potential presentation.</p>
-<p>TTML is expressly designed to meet only a limited set of requirements
-established by <bibref ref="ttaf1-req"/>, and summarized in <specref
-ref="requirements"/>. In particular, only those requirements which service the
-need of performing interchange with existing, legacy distribution systems are
-satisfied.</p>
-<p>In addition to being used for interchange among legacy distribution content
-formats, TTML content may be used directly as a distribution format, providing, for
-example, a standard content format to reference from a <el>&lt;text&gt;</el> or 
-<el>&lt;textstream&gt;</el> media object element in a <bibref
-ref="smil21"/> document. Certain properties of TTML support
-streamability of content, as described in <specref ref="streaming"/>.</p>
-<note>
-<p>While TTML was not expressly designed for direct (embedded) integration into a
-SMIL document instance, such integration is not precluded.</p>
-</note>
-<note>
-<p>In some contexts of use, it may be appropriate to employ
-animated content to depict sign language representations of the same content
-as expressed by a Timed Text document instance. This use case is not
-explicitly addressed by TTML mechanisms, but may be addressed by some
-external multimedia integration technology, such as SMIL.</p>
-</note>
-<div2 id="model">
-<head>System Model</head>
-<p>Use of TTML is intended to function in a wider context of Timed Text
-Authoring and Distribution mechanisms that are based upon a system
-model, depicted in <specref ref="model-graphic"/>, wherein the Timed Text Markup Language
-serves as a bidirectional interchange format among a heterogeneous collection of
-authoring systems, and as a unidirectional interchange format to a
-heterogeneous collection of distribution formats after undergoing transcoding
-or compilation to the target distribution formats as required, and where one
-particular distribution format is TTML.</p>
-<table id="model-graphic" role="example-images">
-<caption>Figure 1 &ndash; System Model</caption>
-<tbody>
-<tr>
-<td><graphic id="graphic-model" source="images/model.png" alt="System Model"/></td>
-</tr>
-</tbody>
-</table>
-</div2>
-<div2 id="example">
-<head>Document Example</head>
-<p>A TTML document instance consists of a <el>tt</el> document element that contains
-a header and a body, where the header specifies document level metadata, styling
-definitions and layout definitions, and the body specifies text content intermixed
-with references to style and layout information and inline timing information.</p>
-<table id="dfxp-example-document-structure" role="example">
-<caption>Example Fragment &ndash; TTML Document Structure</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;tt xml:lang="" xmlns="http://www.w3.org/ns/ttml"&gt;
-  &lt;head&gt;
-    &lt;metadata/&gt;
-    &lt;styling/&gt;
-    &lt;layout/&gt;
-  &lt;/head&gt;
-  &lt;body/&gt;
-&lt;/tt&gt;
-</eg>
-</td></tr>
-</tbody>
-</table>
-<p>Document level metadata may specify a document title, description,
-and copyright information. In addition, arbitrary metadata drawn from
-other namespaces may be specified.</p>
-<table id="dfxp-example-metadata" role="example">
-<caption>Example Fragment &ndash; TTML Metadata</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;metadata xmlns:ttm="http://www.w3.org/ns/ttml#metadata"&gt;
-  &lt;ttm:title&gt;Timed Text TTML Example&lt;/ttm:title&gt;
-  &lt;ttm:copyright&gt;The Authors (c) 2006&lt;/ttm:copyright&gt;
-&lt;/metadata&gt;
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p>Styling information may be specified in the form of style specification
-definitions that are referenced by layout and content information.</p>
-<p>In <specref ref="dfxp-example-styling"/>, four style sets of specifications
-are defined, with one set serving as a collection of default styles.</p>
-<table id="dfxp-example-styling" role="example">
-<caption>Example Fragment &ndash; TTML Styling</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;styling xmlns:tts="http://www.w3.org/ns/ttml#styling"&gt;
-  &lt;!-- s1 specifies default color, font, and text alignment --&gt;
-  &lt;style xml:id="s1"
-    tts:color="white"
-    tts:fontFamily="proportionalSansSerif"
-    tts:fontSize="22px"
-    tts:textAlign="center"
-  /&gt;
-  &lt;!-- alternative using yellow text but otherwise the same as style s1 --&gt;
-  &lt;style xml:id="s2" style="s1" tts:color="yellow"/&gt;
-  &lt;!-- a style based on s1 but justified to the right --&gt;
-  &lt;style xml:id="s1Right" style="s1" tts:textAlign="end" /&gt;     
-  &lt;!-- a style based on s2 but justified to the left --&gt;
-  &lt;style xml:id="s2Left" style="s2" tts:textAlign="start" /&gt;
-&lt;/styling&gt;
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p>Layout information defines one or more regions into which content
-is intended to be presented. A region definition may reference one or
-more sets of style specifications in order to permit content flowed in the
-region to inherit from these styles.
-In <specref ref="dfxp-example-layout"/>, the region definition makes
-reference to style specification <code>s1</code> which allows all content
-flowed into the region to inherit from the region's styles (in the case
-that a style is not already explicitly specified on content or inherited
-via the content hierarchy.)</p>
-<table id="dfxp-example-layout" role="example">
-<caption>Example Fragment &ndash; TTML Layout</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;layout xmlns:tts="http://www.w3.org/ns/ttml#styling"&gt;
-  &lt;region xml:id="subtitleArea"
-    style="s1"
-    tts:extent="560px 62px"
-    tts:padding="5px 3px"
-    tts:backgroundColor="black"
-    tts:displayAlign="after"
-  /&gt;
-&lt;/layout&gt;  
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p>The content of a TTML document instance is expressed in its
-body, which is organized in terms of block and inline text elements.
-The hierarchical organization of content elements serves a primary role in
-determining both spatial and temporal relationships. For example, in
-<specref ref="dfxp-example-body"/>, each paragraph (<el>p</el> element)
-is flowed into its target region in the specified lexical order; furthermore,
-the active time interval of each paragraph is timed in accordance to its
-parent or sibling according to the applicable time containment semantics &mdash;
-in this case, the division parent is interpreted as a parallel time
-container.</p>
-<table id="dfxp-example-body" role="example">
-<caption>Example Fragment &ndash; TTML Body</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;body region="subtitleArea"&gt;
-  &lt;div&gt;
-    &lt;p xml:id="subtitle1" begin="0.76s" end="3.45s"&gt;
-      It seems a paradox, does it not,
-    &lt;/p&gt;
-    &lt;p xml:id="subtitle2" begin="5.0s" end="10.0s"&gt;
-      that the image formed on&lt;br/&gt;
-      the Retina should be inverted?
-    &lt;/p&gt;
-    &lt;p xml:id="subtitle3" begin="10.0s" end="16.0s" style="s2"&gt;
-      It is puzzling, why is it&lt;br/&gt;
-      we do not see things upside-down?
-    &lt;/p&gt;
-    &lt;p xml:id="subtitle4" begin="17.2s" end="23.0s"&gt;
-      You have never heard the Theory,&lt;br/&gt;
-      then, that the Brain also is inverted?
-    &lt;/p&gt;
-    &lt;p xml:id="subtitle5" begin="23.0s" end="27.0s" style="s2"&gt;
-      No indeed! What a beautiful fact!
-    &lt;/p&gt;
-    &lt;p xml:id="subtitle6a" begin="28.0s" end="34.6s" style="s2Left"&gt;
-      But how is it proved?
-    &lt;/p&gt;
-    &lt;p xml:id="subtitle6b" begin="28.0s" end="34.6s" style="s1Right"&gt;
-      Thus: what we call
-    &lt;/p&gt;
-    &lt;p xml:id="subtitle7" begin="34.6s" end="45.0s" style="s1Right"&gt;
-      the vertex of the Brain&lt;br/&gt;
-      is really its base
-    &lt;/p&gt;
-    &lt;p xml:id="subtitle8" begin="45.0s" end="52.0s" style="s1Right"&gt;
-      and what we call its base&lt;br/&gt;
-      is really its vertex,
-    &lt;/p&gt;
-    &lt;p xml:id="subtitle9a" begin="53.5s" end="58.7s"&gt;
-      it is simply a question of nomenclature.
-    &lt;/p&gt;
-    &lt;p xml:id="subtitle9b" begin="53.5s" end="58.7s" style="s2"&gt;
-      How truly delightful!
-    &lt;/p&gt;
-  &lt;/div&gt;    
-&lt;/body&gt;
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p>The first subtitle <specref ref="dfxp-example-subtitle-1"/> is
-presented during the time interval 0.76 to 3.45 seconds.
-This
-subtitle inherits its font family, font size,
-foreground color, and text alignment from the region into which it is
-presented. Since no region is explicitly specified on the paragraph,
-the nearest ancestor that specifies a region determines the
-region. Note also that content is presented
-at the bottom (after edge) of the containing region due to the <code>tts:displayAlign="after"</code>
-being specified on the region definition.</p>
-<note role="explanation">
-<p>The notation "[<emph>X</emph>,<emph>Y</emph>]" denotes a closed
-interval from <emph>X</emph> to <emph>Y</emph>, including
-<emph>X</emph> and <emph>Y</emph>;
-"[<emph>X</emph>,<emph>Y</emph>)" denotes a right half-open
-interval from <emph>X</emph> to <emph>Y</emph>, including
-<emph>X</emph> but not including <emph>Y</emph>;
-"(<emph>X</emph>,<emph>Y</emph>]" denotes a left half-open
-interval from <emph>X</emph> to <emph>Y</emph>, not including
-<emph>X</emph> but including <emph>Y</emph>;
-"(<emph>X</emph>,<emph>Y</emph>)" denotes an open
-interval from <emph>X</emph> to <emph>Y</emph>, not including
-<emph>X</emph> or <emph>Y</emph>.
-</p>
-</note>
-<table id="dfxp-example-subtitle-1" role="example-images">
-<caption>Subtitle 1 &ndash; Time Interval [0.76, 3.45)</caption>
-<tbody>
-<tr>
-<td><graphic source="images/subtitle1.png" alt="Subtitle 1"/></td>
-</tr>
-</tbody>
-</table>
-<p>The second subtitle continues with the default style, except that it contains
-two lines of text with an intervening author-specified line break. Note the effects of
-the use of <code>tts:textAlign="center"</code> to specify the paragraph's alignment
-in the inline progression direction.</p>
-<table id="dfxp-example-subtitle-2" role="example-images">
-<caption>Subtitle 2 &ndash; Time Interval [5.0, 10.0)</caption>
-<tbody>
-<tr>
-<td><graphic source="images/subtitle2.png" alt="Subtitle 2"/></td>
-</tr>
-</tbody>
-</table>
-<p>The third subtitle continues, using a variant style which overrides the default style's
-foreground color with a different color.</p>
-<table id="dfxp-example-subtitle-3" role="example-images">
-<caption>Subtitle 3 &ndash; Time Interval [10.0, 16.0)</caption>
-<tbody>
-<tr>
-<td><graphic source="images/subtitle3.png" alt="Subtitle 3"/></td>
-</tr>
-</tbody>
-</table>
-<p>The fourth subtitle reverts to the default style.</p>
-<table id="dfxp-example-subtitle-4" role="example-images">
-<caption>Subtitle 4 &ndash; Time Interval [17.2, 23.0)</caption>
-<tbody>
-<tr>
-<td><graphic source="images/subtitle4.png" alt="Subtitle 4"/></td>
-</tr>
-</tbody>
-</table>
-<p>The fifth subtitle continues, again using a variant style which
-overrides the default style's foreground color with a different color.</p>
-<table id="dfxp-example-subtitle-5" role="example-images">
-<caption>Subtitle 5 &ndash; Time Interval [23.0, 27.0)</caption>
-<tbody>
-<tr>
-<td><graphic source="images/subtitle5.png" alt="Subtitle 5"/></td>
-</tr>
-</tbody>
-</table>
-<p>During the next active time interval, two distinct subtitles are simultaneously active, with
-the paragraph expressing each subtitle using a different style that overrides color and paragraph
-text alignment of the default style. Note that the flow order is determined by the lexical
-order of elements as they appear in the content hierarchy.</p>
-<table id="dfxp-example-subtitle-6" role="example-images">
-<caption>Subtitles 6a and 6b &ndash; Time Interval [28.0, 34.6)</caption>
-<tbody>
-<tr>
-<td><graphic source="images/subtitle6.png" alt="Subtitles 6a and 6b"/></td>
-</tr>
-</tbody>
-</table>
-<p>The next subtitle is specified in a similar manner using
-a style override to give a paragraph right (end) justified in the
-inline progression direction.</p>
-<table id="dfxp-example-subtitle-7" role="example-images">
-<caption>Subtitle 7 &ndash; Time Interval [34.6, 45.0)</caption>
-<tbody>
-<tr>
-<td><graphic source="images/subtitle7.png" alt="Subtitles 7a and 7b"/></td>
-</tr>
-</tbody>
-</table>
-<p>The eighth subtitle uses the same style override as the previous
-subtitle in order to maintain the right (end) justification of the
-paragraph.</p>
-<table id="dfxp-example-subtitle-8" role="example-images">
-<caption>Subtitle 8 &ndash; Time Interval [47.3, 49.0)</caption>
-<tbody>
-<tr>
-<td><graphic source="images/subtitle8.png" alt="Subtitle 8"/></td>
-</tr>
-</tbody>
-</table>
-<p>During the final (ninth) active time interval, two distinct
-subtitles are again simultaneously active, but with a different
-style applied to the second paragraph to override the default color.
-Note that the flow order is determined by the lexical order of
-elements as they appear in the content hierarchy.</p>
-<table id="dfxp-example-subtitle-9" role="example-images">
-<caption>Subtitles 9a and 9b &ndash; Time Interval [53.5, 58.7)</caption>
-<tbody>
-<tr>
-<td><graphic source="images/subtitle9.png" alt="Subtitles 9a and 9b"/></td>
-</tr>
-</tbody>
-</table>
-<p>The examples shown above demonstrate the primary types of information that may
-be authored using TTML: metadata, styling, layout, timing, and content. In typical cases,
-styling and layout information are separately specified in a document instance. Content information
-is expressed in a hierarchical fashion that embodies the organization of both spatial (flow) and
-timing information. Content makes direct or indirect references to styling and layout information
-and may specify inline overrides to styling.</p>
-</div2>
-</div1>
-<div1 id="definitions">
-<head>Definitions</head>
-<div2 id="acronyms">
-<head>Acronyms</head>
-<glist role="acronyms">
-<gitem>
-<label>DFXP</label>
-<def>
-<p>Distribution Format Exchange Profile</p>
-</def>
-</gitem>
-<gitem>
-<label>TT</label>
-<def>
-<p>Timed Text</p>
-</def>
-</gitem>
-  <gitem>
-    <label>TTML</label>
-    <def>
-      <p>Timed Text Markup Language</p>
-    </def>
-  </gitem>
-  <gitem>
-<label>TT AS</label>
-<def>
-<p>Timed Text Authoring System</p>
-</def>
-</gitem>
-<gitem>
-<label>TT AF</label>
-<def>
-<p>Timed Text Authoring Format</p>
-</def>
-</gitem>
-<gitem>
-<label>TT WG</label>
-<def>
-<p>Timed Text Working Group</p>
-</def>
-</gitem>
-</glist>
-</div2>
-<div2 id="terms">
-<head>Terminology</head>
-<glist>
-<gitem>
-<label>Abstract Document Instance</label>
-<def>
-<p>An instance of an abstract data set as represented by a
-<emph>Reduced XML Infoset</emph>.</p>
-</def>
-</gitem>
-<gitem>
-<label>Abstract Document Type</label>
-<def>
-<p>A set of constraints that defines a class of <emph>XML Information
-Set</emph>s <bibref ref="infoset"/>.</p>
-</def>
-</gitem>
-<gitem>
-<label>Attribute Information Item</label>
-<def>
-<p>Each specified or defaulted attribute  of an XML document corresponds with an attribute information
-item as defined by <bibref ref="infoset"/>, &sect;2.3.</p>
-</def>
-</gitem>
-<gitem>
-<label>Character Information Item</label>
-<def>
-<p>Each data character appearing in an XML document corresponds with a character information
-item as defined by <bibref ref="infoset"/>, &sect;2.6.</p>
-</def>
-</gitem>
-<gitem>
-<label>Content Processor</label>
-<def>
-<p>A processing system capable of importing (receiving) Timed Text Markup Language
-content for the purpose of transforming, presenting, or otherwise processing the content.</p>
-</def>
-</gitem>
-<gitem>
-<label>Content Profile</label>
-<def>
-<p>A collection of features and extensions that are (or may be) employed by
-Timed Text Markup Language content.</p>
-</def>
-</gitem>
-<gitem>
-<label>Content Region</label>
-<def>
-<p>A logical region into which rendered content is placed when modeling or
-performing presentation processing.</p>
-</def>
-</gitem>
-<gitem>
-<label>Element Information Item</label>
-<def>
-<p>Each element appearing in an XML document corresponds with an element information
-item as defined by <bibref ref="infoset"/>, &sect;2.2.</p>
-</def>
-</gitem>
-<gitem>
-<label>Exchange Profile</label>
-<def>
-<p>A content profile that serves a set of needs
-for content interchange.</p>
-</def>
-</gitem>
-<gitem>
-<label>Extension</label>
-<def>
-<p>A syntactic or semantic expression or capability that is defined and
-labeled (using a extension designation) in another (public or private)
-specification.</p>
-</def>
-</gitem>
-<gitem>
-<label>Feature</label>
-<def>
-<p>A syntactic or semantic expression or capability that is defined and
-labeled (using a feature designation) in this specification (or a
-future revision of this specification).</p>
-</def>
-</gitem>
-<gitem>
-<label>Processor</label>
-<def>
-<p>See <emph>Content Processor</emph>.</p>
-</def>
-</gitem>
-<gitem>
-<label>Processor Profile</label>
-<def>
-<p>A collection of features and extensions that must or may be implemented (supported) by
-a content processor.</p>
-</def>
-</gitem>
-<gitem>
-<label>Profile Definition Document</label>
-<def>
-<p>A document that defines a specific collection of features and extensions
-for which support is required or optional in a recipient content
-processor.</p>
-</def>
-</gitem>
-<gitem>
-<label>Region</label>
-<def>
-<p>A logical construct that models authorial intention regarding
-desired or potential presentation processing, and which is represented as
-a rectangular area of a presentation surface into which content
-is composed and rendered during presentation processing.</p>
-</def>
-</gitem>
-<gitem>
-<label>Reduced XML Infoset</label>
-<def>
-<p>An XML Information Set <bibref ref="infoset"/> that satisfieds the
-constraints specify by <specref ref="reduced-infoset"/>.</p>
-</def>
-</gitem>
-<gitem>
-<label>Root Container Region</label>
-<def>
-<p>A logical region that establishes a coordinate system into which
-content regions are placed and optionally clipped.</p>
-</def>
-</gitem>
-<gitem>
-<label>Timed Text</label>
-<def>
-<p>Textual information that is intrinsically or extrinsically
-associated with timing information.</p>
-</def>
-</gitem>
-<gitem>
-<label>Timed Text Markup Language</label>
-<def>
-<p>A content type that represents timed text media for the purpose of
-interchange among authoring systems.</p>
-</def>
-</gitem>
-<gitem>
-<label>Timed Text Authoring System</label>
-<def>
-<p>A content authoring system capable of importing and exporting
-Timed Text Markup Language content.</p>
-</def>
-</gitem>
-</glist>
-</div2>
-<div2 id="conventions">
-<head>Documentation Conventions</head>
-<p>Within normative prose in this specification, the words
-<emph>may</emph>, <emph>should</emph>, and <emph>must</emph> are
-defined as follows:</p>
-<glist role="conformance-keywords">
-<gitem>
-<label>may</label>
-<def>
-<p>Conforming documents and/or TTML processors are permitted to,
-but need not behave as described. </p>
-</def>
-</gitem>
-<gitem>
-<label>should</label>
-<def>
-<p>Conforming documents and/or TTML processors are strongly
-recommended to, but need not behave as described.</p>
-</def>
-</gitem>
-<gitem>
-<label>must</label>
-<def>
-<p>Conforming documents and/or TTML processors are required
-to behave as described; otherwise, they are in error. </p>
-</def>
-</gitem>
-</glist>
-<p>All normative syntactic definitions of XML representations and
-other related terms are depicted with a light orange background color
-and labeled as "XML Representation" or "Syntax Representation", such
-as in the following:</p>
-<table id="elt-syntax-example" role="syntax">
-<caption>XML Representation &ndash; Element Information Item: example</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;example
-  <phrase role="reqattr">count</phrase> = integer
-  size = (<emph>large</emph>|<emph>medium</emph>|<emph>small</emph>) : medium&gt;
-  <emph>Content:</emph> (all | any*)
-&lt;/example&gt;
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p>In an XML representation, bold-face attribute names (e.g. <phrase
-role="strong">count</phrase> above) indicate a required attribute
-information item, and the rest are optional. Where an attribute
-information item has an enumerated type definition, the values are
-shown separated by vertical bars, as for <code>size</code> above; if
-there is a default value, it is shown following a colon. Where an
-attribute information item has a built-in simple type definition
-defined in <bibref ref="xsd-2"/>, a hyperlink to its definition
-therein is given.</p>
-<p>The allowed content of the information item is shown as a grammar
-fragment, using the Kleene operators <code>?</code>, <code>*</code>
-and <code>+</code>. Each element name therein is a hyperlink to its
-own illustration.</p>
-<p>All content of this specification that is not explicitly marked as
-non-normative is considered to be normative. If a section or appendix
-header contains the expression "Non-Normative", then the entirety
-of the section or appendix is considered non-normative.</p>
-<p>All paragraphs marked as a <phrase role="strong">Note</phrase> are considered non-normative.</p>
-<p>Example code fragments are depicted with a light blue-green
-background color and labeled as "Example Fragment", such as in
-the following:</p>
-<table id="example-fragment-1" role="example">
-<caption>Example Fragment &ndash; Sample</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;tt xml:lang="" xmlns="http://www.w3.org/ns/ttml"&gt;
-  &lt;head&gt;
-    &lt;metadata/&gt;
-    &lt;styling/&gt;
-    &lt;layout/&gt;
-  &lt;/head&gt;
-  &lt;body/&gt;
-&lt;/tt&gt;
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-</div2>
-</div1>
-<div1 id="conformance">
-<head>Conformance</head>
-<p>This section specifies the general conformance requirements for
-TTML content and processors.</p>
-<div2 id="conformance-content">
-<head>Content Conformance</head>
-<p>A TTML document instance conforms to this specification if the following criteria are
-satisfied:</p>
-<olist>
-<item>
-<p>When transporting a document instance in a context in which a MIME
-Media Type <bibref ref="mime-media"/> identifies the content type of the interchanged document
-instance, then the specified media type is
-<code>application/ttml+xml</code> in conformance with <bibref
-ref="rfc3023"/> &sect; 7, with which an optional
-<code>profile</code> parameter may appear, the value of which
-conforms to
-a profile designator as
-defined by
-<specref ref="vocabulary-profiles"/>.</p>
-</item>
-<item>
-<p>The document instance is or can be represented as a Reduced XML
-Infoset as defined by <specref ref="reduced-infoset"/>.</p>
-</item>
-<item>
-<p>The Reduced XML
-Infoset that corresponds to the document instance is or can
-be associated with one of the TTML Abstract
-Document Types defined by
-<specref ref="doctypes"/>.</p>
-</item>
-<item>
-<p>The Reduced XML Infoset that corresponds to the document instance is a
-Valid Abstract Document Instance of the associated
-Abstract Document Type.</p>
-</item>
-<item>
-<p>The Reduced XML Infoset satisfies all additional mandatory syntactic and
-semantic constraints defined by this specification. In addition, this Infoset
-should satisfy the web content accessibility guidelines specified by
-<bibref ref="wcag"/>.</p>
-</item>
-</olist>
-</div2>
-<div2 id="conformance-processor">
-<head>Processor Conformance</head>
-<div3 id="conformance-generic-processor">
-<head>Generic Processor Conformance</head>
-<p>A TTML processor conforms to this specification if the following
-generic processor criteria are
-satisfied:</p>
-<olist>
-<item>
-<p>The processor provides at least one mechanism for notionally
-instantiating a Reduced XML
-Infoset representation of a conformant TTML document
-instance.</p>
-</item>
-<item>
-<p>If a process does or can perform validation of a candidate TTML
-document instance, then it provides at least one mechanism to
-implicitly or explicitly associate the
-Reduced XML Infoset representation
-of a conformant TTML document instance with one of the
-TTML Abstract Document Types defined by
-<specref ref="doctypes"/>.</p>
-</item>
-<item>
-<p>The processor does not <emph>a priori</emph> reject or abort the
-processing of a conformant TTML document instance
-unless the processor does not support some required
-(mandatory) feature specified or implied by a TTML content profile
-declared to apply to the document instance.</p>
-</item>
-<item>
-<p>The processor supports all mandatory processing semantics defined by this specification.</p>
-</item>
-<item>
-<p>If the processor supports some optional processing semantics defined by this specification,
-then it does so in a manner consistent with the defined semantics.</p>
-</item>
-</olist>
-</div3>
-<div3 id="conformance-transformation-processor">
-<head>Transformation Processor Conformance</head>
-<p>A TTML processor is a conformant TTML transformation processor if
-the following criteria are satisfied:</p>
-<olist>
-<item>
-<p>The processor satisfies all requirements specified by
-<specref ref="conformance-generic-processor"/>.</p>
-</item>
-<item>
-<p>The processor supports the DFXP Transformation profile as specified
-by <specref ref="profile-dfxp-transformation"/>.</p>
-</item>
-</olist>
-</div3>
-<div3 id="conformance-presentation-processor">
-<head>Presentation Processor Conformance</head>
-<olist>
-<item>
-<p>The processor satisfies all requirements specified by
-<specref ref="conformance-generic-processor"/>.</p>
-</item>
-<item>
-<p>The processor supports the DFXP Presentation profile as specified
-by <specref ref="profile-dfxp-presentation"/>.</p>
-</item>
-</olist>
-</div3>
-</div2>
-<div2 id="claims">
-<head>Claims</head>
-<p>Any claim of compliance with respect to TTML content or processor
-conformance must make
-reference to an implementation compliance statement (ICS).</p>
-<p>An implementation compliance statement must identify all mandatory
-and optional features of this specification that are satisfied by the
-content or processor implementation. In particular, the statement must
-identify the utilized or supported TTML vocabulary profile(s) as
-defined by <specref ref="vocabulary-profiles"/>, and, if a subset or
-superset profile is used or supported, then what features are excluded
-or included in the subset or superset profile.</p>
-<p>A TTML document instance for which a compliance claim is made
-must specify
-either (1)
-a <att>ttp:profile</att> attribute on its root
-<el>tt</el>
-element
-as defined by <specref ref="parameter-attribute-profile"/>
-or (2)
-a <el>ttp:profile</el> element as a child of the
-<el>head</el> element as defined by
-<specref ref="parameter-vocabulary-profile"/>.</p>
-</div2>
-</div1>
-<div1 id="doctypes">
-<head>Document Types</head>
-<p>This section defines the following TTML Abstract Document Types:</p>
-<ulist>
-<item><p><specref ref="dfxp-content-doctype"/></p></item>
-</ulist>
-<p>Each abstract document type consists of the following constraints:</p>
-<ulist>
-<item><p>a non-empty collection of element types, where each element type consists of a name,
-a (possibly empty) collection of attributes, and a content specification</p></item>
-<item><p>a non-empty collection of element types that may appear as the document element</p></item>
-</ulist>
-<p>An Abstract Document Instance may be assessed in terms of validity,
-and is considered to be a Valid Abstract Document Instance if it
-satisfies the following condition: if after</p>
-<olist>
-<item>
-<p>pruning all element information
-items whose names are not members of the collection of element types defined
-by the associated abstract document type, then</p>
-</item>
-<item>
-<p>pruning character
-information item children from any remaining element in case that all
-character children of the element denote XML whitespace characters and the element's type
-is defined as empty in the associated Abstract Document Type, and then</p>
-</item>
-<item>
-<p>pruning all attribute
-information items having expanded names such that the namespace URI of the
-expanded names are not listed in <specref
-ref="namespace-vocab-table"/>,</p>
-</item>
-</olist>
-<p>then the document element is one of the document
-element types permitted by the associated abstract document type,
-the descendants of the document
-element satisfy their respective element type's content
-specifications, all required attributes are present, and the declared
-value of each attribute satisfies the type declared by the
-associated abstract document type.</p>
-<note>
-<p>While a conformant processor may not <emph>a priori</emph> reject a
-conformant document instance that adheres to a
-supported content profile, a given document instance may be
-constrained by the author or authoring tool to satisfy a more
-restrictive definition of validity.</p>
-</note>
-<div2 id="dfxp-content-doctype">
-<head>DFXP Content</head>
-<p>DFXP Content is an abstract document type of a profile of the Timed Text Markup Language intended
-to be used for interchange among distribution systems. This document type
-is defined in terms of the
-element and attribute vocabulary
-specified in <specref ref="vocabulary"/>.</p>
-<p>This specification defines two types of normative schemas that may be used to validate a subset of
-conformant DFXP Content document instances:</p>
-<ulist>
-<item><p><specref ref="dfxp-schema-rnc"/></p></item>
-<item><p><specref ref="dfxp-schema-xsd"/></p></item>
-</ulist>
-<p>The (root) document element of a DFXP Content document instance must be a
-<el>tt</el> element, as defined by <specref
-ref="document-structure-vocabulary-tt"/>.</p>
-<note role="clarification">
-<p>The schemas included in this specification do not validate all syntactic constraints
-defined by this specification. In particular, performing validation with one of the above
-referenced schemas may result in a <emph>false positive</emph> indication of validity.
-However, with one exception, their
-use will not produce a <emph>false negative</emph> indication of validity
-when used with a compliant validating
-processor.</p>
-<p>In exception to the above statement about false negatives,
-if the Relax NG schema included in this specification is used to validate a
-TTML Document containing elements in a foreign namespace and the <att>xml:id</att>
-attribute is used with any of those (foreign) elements,
-then an error will be reported even though such usage is permitted by this
-specification. In this case, the false negative arises due
-to a specific limitation in expressing wildcard patterns involving <code>xsd:ID</code>
-typed attributes in Relax NG schemas.
-Note that this specification defines the formal validity of a TTML Document to be
-based on an abstract document instance from which all foreign namespace elements and
-attributes have been removed. Therefore, the exceptional reporting of this false
-negative does not impact the formal assessment of TTML Document validity.</p>
-</note>
-</div2>
-</div1>
-<div1 id="vocabulary">
-<head>Vocabulary</head>
-<p>This section defines the
-namespaces, profiles, and vocabulary (as an element an attribute
-catalog) of the Timed Text Markup Language (TTML) as follows:</p>
-<ulist>
-<item><p><specref ref="vocabulary-namespaces"/></p></item>
-<item><p><specref ref="vocabulary-profiles"/></p></item>
-<item><p><specref ref="vocabulary-overview"/></p></item>
-</ulist>
-<div2 id="vocabulary-namespaces">
-<head>Namespaces</head>
-<p>The Timed Text Markup Language (TTML) employs a number of
-namespaces for elements and certain
-global attributes. The following table specifies this set of namespaces
-and indicates the default prefix used within this specification and the
-normative URI that denotes each namespace.</p>
-<note role="explanation">
-<p>In a specific document instance, it is not required that the default
-prefixes shown below are used. Any prefix or namespace binding that satisfies the constraints
-of XML Namespaces may be used that is associated with the specified namespace URI.</p>
-</note>
-<table id="namespace-vocab-table" role="common">
-<caption>Table 1 &ndash; Namespaces</caption>
-<col width="30%"/>
-<tbody>
-<tr>
-<th>Name</th>
-<th>Prefix</th>
-<th>Value</th>
-</tr>
-<tr>
-<td>TT</td>
-<td><code>tt:</code></td>
-<td><code>http://www.w3.org/ns/ttml</code></td>
-</tr>
-<tr>
-<td>TT Parameter</td>
-<td><code>ttp:</code></td>
-<td><code>http://www.w3.org/ns/ttml#parameter</code></td>
-</tr>
-<tr>
-<td>TT Style</td>
-<td><code>tts:</code></td>
-<td><code>http://www.w3.org/ns/ttml#styling</code></td>
-</tr>
-<tr>
-<td>TT Metadata</td>
-<td><code>ttm:</code></td>
-<td><code>http://www.w3.org/ns/ttml#metadata</code></td>
-</tr>
-<tr>
-<td>TT Profile</td>
-<td><emph>none</emph></td>
-<td><code>http://www.w3.org/ns/ttml/profile/</code></td>
-</tr>
-<tr>
-<td>TT Feature</td>
-<td><emph>none</emph></td>
-<td><code>http://www.w3.org/ns/ttml/feature/</code></td>
-</tr>
-<tr>
-<td>TT Extension</td>
-<td><emph>none</emph></td>
-<td><code>http://www.w3.org/ns/ttml/extension/</code></td>
-</tr>
-</tbody>
-</table>
-<note role="clarification">
-<p>If a reference to an element type is used in this specification and the name
-of the element type is not namespace qualified, then the TT Namespace applies.</p>
-<p>For certain namespaces defined above, the default prefix
-is specified as <emph>none</emph> if no XML vocabulary is defined in
-the namespace by this specification (nor expected to be defined in a
-future version of this specification). In such cases, the use of the
-namespace URI is for purposes other than defining XML vocabulary,
-e.g., for designating profiles, features, extensions and for
-dereferencing standard profile definitions.</p>
-</note>
-<p>All TTML Namespaces are <loc
-href="http://www.w3.org/2001/tag/doc/namespaceState#namespacedef"><emph>mutable</emph></loc>
-<bibref ref="nsstate"/>; all undefined names in these namespaces are reserved for future
-standardization by the W3C.</p>
-</div2>
-<div2 id="vocabulary-profiles">
-<head>Profiles</head>
-<p>The Timed Text Markup Language (TTML) employs a number of
-standard, predefined profiles of its
-vocabulary and associated semantics.
-The following table specifies this set of
-profiles, indicating
-a normative name
-and designator for each
-predefined profile,
-and where each of these profiles is formally elaborated in
-<specref ref="profiles"/>.</p>
-<table id="profile-vocab-table" role="common">
-<caption>Table 2 &ndash; Profiles</caption>
-<col width="25%"/>
-<tbody>
-<tr>
-<th>Name</th>
-<th>Designator</th>
-</tr>
-<tr>
-<td>DFXP Transformation</td>
-<td><code>http://www.w3.org/ns/ttml/profile/dfxp-transformation</code></td>
-</tr>
-<tr>
-<td>DFXP Presentation</td>
-<td><code>http://www.w3.org/ns/ttml/profile/dfxp-presentation</code></td>
-</tr>
-<tr>
-<td>DFXP Full</td>
-<td><code>http://www.w3.org/ns/ttml/profile/dfxp-full</code></td>
-</tr>
-</tbody>
-</table>
-<p/>
-<p>A profile designator must adhere to the
-<code>xsd:anyURI</code> data type defined by <bibref ref="xsd-2"/>,
-&sect;3.2.17. If the profile designator is expressed as a relative URI,
-then it must be absolutized by using the TT Profile Namespace value as
-the base URI.</p>
-<note role="example">
-<p>For example, if a profile designator is expressed as
-<code>dfxp-presentation</code>, then the absolutized profile designator
-would be
-<code>http://www.w3.org/ns/ttml/profile/dfxp-presentation</code>.</p>
-</note>
-<p>A profile designator is not restricted to the set of designators enumerated
-in <specref ref="profile-vocab-table"/>, but may be any URI that
-feasibly dereferences a TTML Profile Definition Document.</p>
-<p>The profile of TTML that must be supported by a
-TTML content processor in order to process a document
-instance is specified either (1) by specifying a
-<att>ttp:profile</att> attribute on the root <el>tt</el> element, as
-defined by <specref ref="parameter-attribute-profile"/>, or (2) by
-including one or more <el>ttp:profile</el>
-elements in the <el>head</el> element, in
-accordance with <specref ref="parameter-vocabulary-profile"/>.</p>
-<p>If a <el>ttp:profile</el> element appears as a
-descendant of the <el>tt</el> element, then the <loc
-href="#parameter-attribute-profile"><att>ttp:profile</att></loc>
-attribute should not be specified on the <el>tt</el> element. If both
-a <el>ttp:profile</el> element and a <att>ttp:profile</att>
-attribute are present (in a given document instance), then the
-<att>ttp:profile</att> attribute must be ignored for the purpose of
-determining the declared profile requirements.</p>
-<p>If more than one <el>ttp:profile</el> element appears in
-a TTML document instance, then all specified profiles apply
-simultaneously.  In such a case, if some feature or some extension is
-specified by one profile to be used (mandatory and enabled) and by
-another profile to be required (mandatory) or optional (voluntary),
-then that feature or extension must be considered to be used
-(mandatory and enabled); if some feature or some extension is
-specified by one profile to be merely required (mandatory) and by
-another profile to be optional (voluntary), then that feature or
-extension must be considered to be required (mandatory).</p>
-<p>If neither
-<loc href="#parameter-attribute-profile"><att>ttp:profile</att></loc>
-attribute nor
-<loc href="#parameter-vocabulary-profile"><el>ttp:profile</el></loc>
-element is present in a TTML document instance, and if the document
-interchange context does not specify a profile,
-then the DFXP Transformation
-profile applies.</p>
-<note role="elaboration">
-<p>It is intended that the <att>ttp:profile</att> attribute be used when
-the author wishes to reference one of the standard, predefined profiles of
-TTML content, and does not wish to modify (by supersetting or subsetting)
-that profile. This attribute may also be used by an author to indicate the use
-of a non-standard profile, in which case the specified profile designator expresses
-a URI that denotes an externally defined TTML Profile Definition Document.
-However, it is not required that a conformant TTML content processor be able
-to dereference such an externally specified profile definition.</p>
-<p>In contrast, it is intended that the <el>ttp:profile</el> element be
-used when the author wishes to make use of a modified predefined profile or
-wishes to include in the document instance a non-standard profile definition
-not based upon one of the predefined profiles.</p>
-<p>A predefined profile is supersetted by specifying some feature or extension to
-be required (mandatory) that was either not specified in the underlying, baseline
-profile or was specified as optional (voluntary) in the baseline profile.
-A predefined profile is subsetted by specifying some feature or extension to
-be optional (voluntary) that was specified as required in the underlying, baseline
-profile.</p>
-<p>When a baseline profile is modified by subsetting, the resulting, derived profile
-is referred to as a <emph>subtractive</emph> profile; when modified by supersetting, the result
-is referred to as an <emph>additive</emph> profile.
-It is also possible to define a derived profile that is simultaneously subtractive
-and additive.</p>
-</note>
-<p>If a TTML document instance makes use of a feature defined by
-<specref ref="feature-designations"/> and if the intended use of the
-document requires the recognition and processing of that feature, then
-the document must include a <emph>required feature</emph> or
-a <emph>used feature</emph>
-specification in one of its declared or
-referenced profiles.  If a TTML document instance makes use
-of an extension designatable by <specref
-ref="extension-designations"/> and if the intended use of the document
-requires the recognition and processing of that extension, then the
-document must include a <emph>required extension</emph> or
-a <emph>used extension</emph> specification
-in one of its declared or referenced
-profiles.</p>
-<note role="elaboration">
-<p>A required or used feature
-specification is expressed directly (or indirectly by referring to a
-profile) by means of a <loc
-href="#parameter-vocabulary-feature"><el>ttp:feature</el></loc>
-element where the value of its <att>value</att> attribute is
-<code>required</code> or <code>use</code>,
-respectively.  A required or used
-extension specification is expressed directly (or indirectly by
-referring to a profile) by means of a <loc
-href="#parameter-vocabulary-extension"><el>ttp:extension</el></loc>
-element where the value of its <att>value</att> attribute is
-<code>required</code> or <code>use</code>,
-respectively.</p>
-</note>
-<p>An example of an author defined
-additive, derived profile of the DFXP Presentation
-profile is shown
-below in <specref ref="dfxp-example-sub-profile"/>.</p>
-<table id="dfxp-example-sub-profile" role="example">
-<caption>Example Fragment &ndash; DFXP Additive Profile</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;tt xml:lang="" xmlns="http://www.w3.org/ns/ttml"&gt;
- &lt;head&gt;
-   &lt;profile use="dfxp-presentation" xmlns="http://www.w3.org/ns/ttml#parameter"&gt;
-     &lt;features xml:base="http://www.w3.org/ns/ttml/feature/"&gt;
-       &lt;feature value="required"&gt;#fontStyle-italic&lt;/feature&gt;
-     &lt;/features&gt;
-   &lt;/profile&gt;
- &lt;/head&gt;
- &lt;body/&gt;
-&lt;/tt&gt;
-</eg>
-</td></tr>
-</tbody>
-</table>
-<note role="explanation">
-<p>In the above example, the baseline profile is declared to be
-the DFXP Presentation profile, which is then additively modified by making the
-<code>#fontStyle-italic</code> feature required (rather than
-optional as it is defined
-in <specref ref="profile-dfxp-presentation"/>). Note also the resetting of the
-default XMLNS binding on the <el>profile</el> element to the TT Parameter Namespace.</p>
-</note>
-</div2>
-<div2 id="vocabulary-overview">
-<head>Catalog</head>
-<p>The vocabulary of the Timed Text Markup Language (TTML) is
-defined in the following major catalogs (divisions of vocabulary):</p>
-<ulist>
-<item><p><specref ref="core-vocabulary-overview"/></p></item>
-<item><p><specref ref="extension-vocabulary-overview"/></p></item>
-</ulist>
-<p>The core catalog defines the baseline, core vocabulary of TTML,
-and, in particular, the vocabulary of DFXP Content. The extension catalog
-serves as a placeholder for extensions to the core vocabulary defined
-by TTML.</p>
-<div3 id="core-vocabulary-overview">
-<head>Core Catalog</head>
-<p>The core vocabulary catalog is intended to satisfy the needs of
-TTML while providing a baseline vocabulary for future profiles. This vocabulary
-is divided into distinct categories, specified in detail
-in the following sections:</p>
-<ulist>
-<item><p><specref ref="parameters"/></p></item>
-<item><p><specref ref="content"/></p></item>
-<item><p><specref ref="styling"/></p></item>
-<item><p><specref ref="layout"/></p></item>
-<item><p><specref ref="timing"/></p></item>
-<item><p><specref ref="animation"/></p></item>
-<item><p><specref ref="metadata"/></p></item>
-</ulist>
-<p>The core element vocabulary specified for use with a TTML document
-instance is enumerated in
-<specref ref="element-vocab-table"/>.</p>
-<table id="element-vocab-table" role="common">
-<caption>Table 3 &ndash; Element Vocabulary</caption>
-<col width="25%"/>
-<tbody>
-<tr>
-<th>Module</th>
-<th>Elements</th>
-</tr>
-<tr>
-<td>
-Animation
-</td>
-<td>
-<loc href="#animation-vocabulary-set">set</loc>
-</td>
-</tr>
-<tr>
-<td>
-Content
-</td>
-<td>
-<loc href="#document-structure-vocabulary-body">body</loc>,
-<loc href="#content-vocabulary-div">div</loc>,
-<loc href="#content-vocabulary-p">p</loc>,
-<loc href="#content-vocabulary-span">span</loc>,
-<loc href="#content-vocabulary-br">br</loc>
-</td>
-</tr>
-<tr>
-<td>
-Document
-</td>
-<td>
-<loc href="#document-structure-vocabulary-tt">tt</loc>
-</td>
-</tr>
-<tr>
-<td>
-Head
-</td>
-<td>
-<loc href="#document-structure-vocabulary-head">head</loc>
-</td>
-</tr>
-<tr>
-<td>
-Layout
-</td>
-<td>
-<loc href="#layout-vocabulary-layout">layout</loc>,
-<loc href="#layout-vocabulary-region">region</loc>
-</td>
-</tr>
-<tr>
-<td>
-Metadata
-</td>
-<td>
-<loc href="#metadata-vocabulary-metadata">metadata</loc>
-</td>
-</tr>
-<tr>
-<td>
-Metadata Items
-</td>
-<td>
-<loc href="#metadata-vocabulary-actor">ttm:actor</loc>,
-<loc href="#metadata-vocabulary-agent">ttm:agent</loc>,
-<loc href="#metadata-vocabulary-copyright">ttm:copyright</loc>,
-<loc href="#metadata-vocabulary-desc">ttm:desc</loc>,
-<loc href="#metadata-vocabulary-name">ttm:name</loc>,
-<loc href="#metadata-vocabulary-title">ttm:title</loc>
-</td>
-</tr>
-<tr>
-<td>Parameter Items</td>
-<td><loc href="#parameter-vocabulary-profile">ttp:profile</loc>,
-<loc href="#parameter-vocabulary-features">ttp:features</loc>,
-<loc href="#parameter-vocabulary-feature">ttp:feature</loc>,
-<loc href="#parameter-vocabulary-extensions">ttp:extensions</loc>,
-<loc href="#parameter-vocabulary-extension">ttp:extension</loc>
-</td>
-</tr>
-<tr>
-<td>
-Styling
-</td>
-<td>
-<loc href="#styling-vocabulary-styling">styling</loc>,
-<loc href="#styling-vocabulary-style">style</loc>
-</td>
-</tr>
-</tbody>
-</table>
-<p/>
-<p>Element vocabulary groups that are used in defining content models
-for TTML element types are enumerated in <specref ref="element-vocab-group-table"/>.</p>
-<table id="element-vocab-group-table" role="common">
-<caption>Table 4 &ndash; Element Vocabulary Groups</caption>
-<col width="25%"/>
-<tbody>
-<tr>
-<th>Group</th>
-<th>Elements</th>
-</tr>
-<tr>
-<td>
-Animation.class
-</td>
-<td>
-<loc href="#animation-vocabulary-set">set</loc>
-</td>
-</tr>
-<tr>
-<td>
-Block.class
-</td>
-<td>
-<loc href="#content-vocabulary-div">div</loc> |
-<loc href="#content-vocabulary-p">p</loc>
-</td>
-</tr>
-<tr>
-<td>
-Inline.class
-</td>
-<td>
-<loc href="#content-vocabulary-span">span</loc> |
-<loc href="#content-vocabulary-span">br</loc> |
-<code>#PCDATA</code>
-</td>
-</tr>
-<tr>
-<td>
-Metadata.class
-</td>
-<td>
-<loc href="#metadata-vocabulary-metadata">metadata</loc> |
-<loc href="#metadata-vocabulary-copyright">ttm:agent</loc> |
-<loc href="#metadata-vocabulary-copyright">ttm:copyright</loc> |
-<loc href="#metadata-vocabulary-desc">ttm:desc</loc> |
-<loc href="#metadata-vocabulary-title">ttm:title</loc>
-</td>
-</tr>
-<tr>
-<td>Parameters.class</td>
-<td><loc
-href="#parameter-vocabulary-profile">ttp:profile</loc></td>
-</tr>
-</tbody>
-</table>
-<p/>
-<p>The attribute vocabulary specified for use with the core vocabulary
-catalog is enumerated in
-<specref ref="attribute-vocab-table"/>.</p>
-<table id="attribute-vocab-table" role="common">
-<caption>Table 5 &ndash; Attribute Vocabulary</caption>
-<col width="25%"/>
-<tbody>
-<tr>
-<th>Module</th>
-<th>Attributes</th>
-</tr>
-<tr>
-<td>
-Core Attributes
-</td>
-<td>
-<loc href="#content-attribute-id">xml:id</loc>,
-<loc href="#content-attribute-lang">xml:lang</loc>,
-<loc href="#content-attribute-space">xml:space</loc>
-</td>
-</tr>
-<tr>
-<td>
-Layout
-</td>
-<td>
-<loc href="#layout-attribute-region">region</loc>
-</td>
-</tr>
-<tr>
-<td>
-Metadata Attributes
-</td>
-<td>
-<loc href="#metadata-attribute-agent">ttm:agent</loc>,
-<loc href="#metadata-attribute-role">ttm:role</loc>
-</td>
-</tr>
-<tr>
-<td>
-Parameter Attributes
-</td>
-<td>
-<loc href="#parameter-attribute-cellResolution">ttp:cellResolution</loc>,
-<loc href="#parameter-attribute-clockMode">ttp:clockMode</loc>,
-<loc href="#parameter-attribute-dropMode">ttp:dropMode</loc>,
-<loc href="#parameter-attribute-frameRate">ttp:frameRate</loc>,
-<loc href="#parameter-attribute-frameRateMultiplier">ttp:frameRateMultipler</loc>,
-<loc href="#parameter-attribute-markerMode">ttp:markerMode</loc>,
-<loc href="#parameter-attribute-pixelAspectRatio">ttp:pixelAspectRatio</loc>,
-<loc href="#parameter-attribute-profile">ttp:profile</loc>,
-<loc href="#parameter-attribute-subFrameRate">ttp:subFrameRate</loc>,
-<loc href="#parameter-attribute-tickRate">ttp:tickRate</loc>,
-<loc href="#parameter-attribute-timeBase">ttp:timeBase</loc>
-</td>
-</tr>
-<tr>
-<td>
-Styling
-</td>
-<td>
-<loc href="#style-attribute-style">style</loc>
-</td>
-</tr>
-<tr>
-<td>
-Styling Attributes
-</td>
-<td>
-<loc href="#style-attribute-backgroundColor">tts:backgroundColor</loc>,
-<loc href="#style-attribute-color">tts:color</loc>,
-<loc href="#style-attribute-direction">tts:direction</loc>,
-<loc href="#style-attribute-display">tts:display</loc>,
-<loc href="#style-attribute-displayAlign">tts:displayAlign</loc>,
-<loc href="#style-attribute-extent">tts:extent</loc>,
-<loc href="#style-attribute-fontFamily">tts:fontFamily</loc>,
-<loc href="#style-attribute-fontSize">tts:fontSize</loc>,
-<loc href="#style-attribute-fontStyle">tts:fontStyle</loc>,
-<loc href="#style-attribute-fontWeight">tts:fontWeight</loc>,
-<loc href="#style-attribute-lineHeight">tts:lineHeight</loc>,
-<loc href="#style-attribute-opacity">tts:opacity</loc>,
-<loc href="#style-attribute-origin">tts:origin</loc>,
-<loc href="#style-attribute-overflow">tts:overflow</loc>,
-<loc href="#style-attribute-padding">tts:padding</loc>,
-<loc href="#style-attribute-showBackground">tts:showBackground</loc>,
-<loc href="#style-attribute-textAlign">tts:textAlign</loc>,
-<loc href="#style-attribute-textDecoration">tts:textDecoration</loc>,
-<loc href="#style-attribute-textOutline">tts:textOutline</loc>,
-<loc href="#style-attribute-unicodeBidi">tts:unicodeBidi</loc>,
-<loc href="#style-attribute-visibility">tts:visibility</loc>,
-<loc href="#style-attribute-wrapOption">tts:wrapOption</loc>,
-<loc href="#style-attribute-writingMode">tts:writingMode</loc>,
-<loc href="#style-attribute-zIndex">tts:zIndex</loc>
-</td>
-</tr>
-<tr>
-<td>
-Timing Attributes
-</td>
-<td>
-<loc href="#timing-attribute-begin">begin</loc>,
-<loc href="#timing-attribute-dur">dur</loc>,
-<loc href="#timing-attribute-end">end</loc>,
-<loc href="#timing-attribute-timeContainer">timeContainer</loc>
-</td>
-</tr>
-</tbody>
-</table>
-<note role="explanation">
-<p>Only those attributes defined as either (1) global, i.e., namespace qualified, or
-(2) shared element-specific, i.e., not namespace qualified but shared across multiple
-element types, are listed in <specref ref="attribute-vocab-table"/> above.
-</p>
-</note>
-<note role="explanation">
-<p>All vocabulary defined by TTML consistently makes use of
-the so-called <emph>lowerCamelCase</emph> naming convention. In some cases, this results in the
-change of a name when the name was based upon another specification
-that used a different naming convention.</p>
-</note>
-</div3>
-<div3 id="extension-vocabulary-overview">
-<head>Extension Catalog</head>
-<p>The extension vocabulary catalog is intended for use by future
-profiles of TTML, and is not further defined
-by this version of this specification.</p>
-<p>In addition to standardized extension vocabulary, a conforming TTML
-document instance may contain arbitrary namespace qualified
-elements that reside in any namespace other than those namespaces
-defined for use with this specification. Furthermore, a conforming TTML
-document instance may contain arbitrary namespace qualified
-attributes on TTML defined vocabulary where such attributes reside in
-any namespace other than those defined for use with this
-specification.</p>
-</div3>
-</div2>
-</div1>
-<div1 id="parameters">
-<head>Parameters</head>
-<p>This section specifies the <emph>parameters</emph> matter of the
-core vocabulary catalog, where
-parameters are to be understood as information that is either (1)
-essential or (2) of significant importance for the purpose of
-interpreting the semantics of other types of information expressed by
-core vocabulary items or for establishing a processing context by means
-of which TTML content can be related to an external environment.</p>
-<div2 id="parameter-element-vocabulary">
-<head>Parameter Element Vocabulary</head>
-<p>The following elements, all defined in the TT Parameter
-Namespace, specify parametric information that applies to a document
-or a content processor:</p>
-<ulist>
-<item><p><specref ref="parameter-vocabulary-profile"/></p></item>
-<item><p><specref ref="parameter-vocabulary-features"/></p></item>
-<item><p><specref ref="parameter-vocabulary-feature"/></p></item>
-<item><p><specref ref="parameter-vocabulary-extensions"/></p></item>
-<item><p><specref ref="parameter-vocabulary-extension"/></p></item>
-</ulist>
-<div3 id="parameter-vocabulary-profile">
-<head>ttp:profile</head>
-<p>The <el>ttp:profile</el> element is used to specify a collection of
-used (mandatory and enabled), required (mandatory),
-and optional (voluntary) features and extensions that must or
-may be supported by a TTML content processor in order to process a TTML
-document that makes use (or may make use) of such features and
-extensions.</p>
-<note role="clarification">
-<p>The difference between a <emph>feature</emph> and an
-<emph>extension</emph> is where it is defined and how it is labeled:
-if defined in this specification (or a future revision thereof) and
-labeled with a feature designation in <specref ref="features"/>, then
-it is considered to be a feature; if defined in another specification
-and labeled there with an extension designation, then it is considered
-to be an extension. In general, features are expected to be defined by
-the W3C standards process, while extensions are expected to be defined by
-third parties.</p>
-</note>
-<p>This specification defines two distinct uses of the <el>ttp:profile</el> element:</p>
-<ulist>
-<item>
-<p>as a child of the <el>head</el> element within a TTML document
-instance;</p>
-</item>
-<item>
-<p>as the root element of a TTML Profile Definition document
-instance;</p>
-</item>
-</ulist>
-<p>When a <el>tt:profile</el> element appears within a TTML document
-instance, its purpose is to express authorial intentions about which
-features and extensions must or may be supported by a recipient
-content processor. In addition, the element indirectly expresses
-information about the set of features or extensions that are (or may
-expected to be) used by the document instance.</p>
-<p>When a <el>tt:profile</el> element is used by a TTML
-Profile Definition document instance, it serves to publish a machine
-readable specification of a specific TTML content profile, of which
-this specification defines three such Profile Definition Documents in
-<specref ref="profiles"/>.</p>
-<p>The <el>ttp:profile</el> element accepts as its children zero or more
-elements in the <code>Metadata.class</code> element group, followed by
-zero or more <el>ttp:features</el> elements, followed by
-zero or more <el>ttp:extensions</el> elements.</p>
-<table id="elt-syntax-parameter-profile" role="syntax">
-<caption>XML Representation &ndash; Element Information Item: ttp:profile</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;ttp:profile
-  use = string
-  <loc href="#content-attribute-id">xml:id</loc> = ID
-  {<emph>any attribute not in default or any TT namespace</emph>}&gt;
-  <emph>Content:</emph> <loc href="#element-vocab-group-table">Metadata.class</loc>*, <loc href="#parameter-vocabulary-features">ttp:features</loc>*, <loc href="#parameter-vocabulary-extensions">ttp:extensions</loc>*
-&lt;/ttp:profile&gt;
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p>If specified, the <att>use</att> attribute must adhere to the
-<code>xsd:anyURI</code> data type defined by <bibref ref="xsd-2"/>,
-&sect;3.2.17, and, furthermore, must denote a profile designator in
-accordance with <specref ref="vocabulary-profiles"/>. In this case,
-the profile designator must refer to (1) a standard, predefined
-TTML Profile Definition Document as defined by <specref ref="profiles"/>,
-or (2) a dereferenceable resource representing a valid TTML Profile Definition
-document instance. In either case, the referenced profile serves as the
-baseline profile of the specifying <el>ttp:profile</el> element.</p>
-<p>If the <att>use</att> attribute is not specified, then the baseline
-profile of the <el>ttp:profile</el> element must be considered to be
-the empty (null) profile, i.e., a profile definition containing no
-feature or extension specifications.</p>
-<p>The collection of features and extensions of a profile are determined according
-to the following ordered rules:</p>
-<olist>
-<item>
-<p>initialize the features and extensions of the profile to the empty
-set;</p>
-</item>
-<item>
-<p>if a <att>use</att> attribute is present, then augment the profile
-with the set of features and extensions specified by the referenced
-baseline profile;</p>
-</item>
-<item>
-<p>for each <el>ttp:feature</el> and <el>ttp:extension</el> element
-descendant of the <el>ttp:profile</el> element, using a post-order
-traversal, merge the specified feature or extension with the features
-and extensions of the profile, where merging a feature or extension
-entails replacing an existing feature or extension specification, if
-it already exists, or adding a new feature or extension specification,
-if it does not yet exist in the profile;</p>
-</item>
-</olist>
-<p>A conformant TTML processor is not required to be able to
-dereference a TTML Profile Definition Document that is not one of the
-standard, predefined profiles defined by <specref ref="profiles"/>.  A
-conformant TTML processor may make use of a built-in, static
-form of each standard, predefined profile so as not to require
-dereferencing a network resource.</p>
-<p>If a TTML processor is unable to dereference a non-standard TTML
-Profile Definition Document, then it must not further process the
-document without the presence of an explicit override from an end-user
-or some implementation specific parameter traceable to an end-user or
-to a user or system configuration setting. If a TTML processor aborts
-processing of a TTML document instance due to the inability to
-reference a non-standard TTML Profile Definition Document, then some
-end-user notification should be given unless the end-user or system
-has disabled such a notification, or if the processor does not permit
-or entail the intervention of an end-user.</p>
-<p>The <el>ttp:profile</el> element is illustrated by the following example.</p>
-<table id="parameter-vocabulary-profile-example-1" role="example">
-<caption>Example Fragment &ndash; ttp:profile</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;ttp:profile use="dfxp-presentation"&gt;
-  &lt;ttp:features xml:base="http://www.w3.org/ns/ttml/feature/"&gt;
-    &lt;ttp:feature&gt;#text-outline&lt;/ttp:feature&gt;
-  &lt;/ttp:features&gt;
-&lt;/ttp:profile&gt;
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<note role="explanation">
-<p>In the above example, the DFXP presentation profile is used as the
-baseline profile. This baseline profile is then supersetted (thus
-creating an additive derived profile) by requiring support for
-<code>#text-outline</code> feature.</p>
-</note>
-</div3>
-<div3 id="parameter-vocabulary-features">
-<head>ttp:features</head>
-<p>The <el>ttp:features</el> element is a container element used to group
-infomation about feature support requirements.</p>
-<p>The <el>ttp:features</el> element accepts as its children zero or more
-elements in the <code>Metadata.class</code> element group, followed by
-zero or more <el>ttp:feature</el> elements.</p>
-<table id="elt-syntax-parameter-features" role="syntax">
-<caption>XML Representation &ndash; Element Information Item: ttp:features</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;ttp:features
-  xml:base = string : <emph>TT Feature Namespace</emph>
-  <loc href="#content-attribute-id">xml:id</loc> = ID
-  {<emph>any attribute not in default or any TT namespace</emph>}&gt;
-  <emph>Content:</emph> <loc href="#element-vocab-group-table">Metadata.class</loc>*, <loc href="#parameter-vocabulary-feature">ttp:feature</loc>*
-&lt;/ttp:features&gt;
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p>If specified, the <att>xml:base</att>
-attribute must (1) adhere to the
-<code>xsd:anyURI</code> data type defined by <bibref ref="xsd-2"/>,
-&sect;3.2.17, (2) express an absolute URI that
-adheres to <bibref ref="xmlbase"/> and,
-(3) express a feature namespace as defined by
-<specref ref="feature-designations"/>. If not specified, the
-<att>xml:base</att> attribute's default
-value applies, which is the TT Feature Namespace.</p>
-<p>The <att>xml:base</att> attribute is
-used to permit the abbreviation of feature designation URIs expressed
-by child <el>ttp:feature</el> elements.</p>
-</div3>
-<div3 id="parameter-vocabulary-feature">
-<head>ttp:feature</head>
-<p>The <el>ttp:feature</el> element is used to specify
-infomation about support requirements for a particular feature.</p>
-<p>The children of the <el>ttp:feature</el> element must express a non-empty
-sequence of character information items that adheres to the
-<code>xsd:anyURI</code> data type defined by <bibref ref="xsd-2"/>,
-&sect;3.2.17.</p>
-<table id="elt-syntax-parameter-feature" role="syntax">
-<caption>XML Representation &ndash; Element Information Item: ttp:feature</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;ttp:feature
-  value = (optional|required|use) : required
-  <loc href="#content-attribute-id">xml:id</loc> = ID
-  {<emph>any attribute not in default or any TT namespace</emph>}&gt;
-  <emph>Content:</emph> #PCDATA
-&lt;/ttp:feature&gt;
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p>If the URI expressed by the content of the <el>ttp:feature</el>
-element is a relative URI, then, when combined with the
-feature namespace value expressed by the
-<att>xml:base</att> attribute of the
-nearest ancestor <el>ttp:features</el> element, it must express an
-absolute URI.  In either case (original absolute URI or resulting
-absolutized URI), the URI expressed by the <el>ttp:feature</el>
-element must further adhere to the syntax of a feature designation as
-defined by <specref ref="feature-designations"/>.</p> <p>If
-the URI expressed by the content of the <el>ttp:feature</el> element
-is a relative URI, then an <att>xml:base</att> attribute should be
-specified on the nearest ancestor <el>ttp:features</el> element.</p>
-<p>The <att>value</att> attribute specifies whether a conforming TTML
-processor must or may implement the designated feature in order to
-process the document. If the value of the <att>value</att> attribute
-is <code>optional</code>, then the processor need
-not implement or otherwise support the feature in order to process the
-document; if the value is <code>required</code>, then the processor
-must implement or otherwise support the feature in order to process
-the document; if the value is
-<code>use</code>, then the processor must both (1) implement or
-otherwise support the feature and (2) enable (activate) use of the
-feature.</p>
-
-<note role="clarification">
-<p>The default value of the <att>value</att> attribute is
-<code>required</code>, as indicated in the above element information
-item definition. Therefore, if a <att>value</att> attribute is not
-specified on a <el>ttp:feature</el> element, it is equivalent to
-specifying that support for the feature is required.</p>
-</note>
-<p>If the value of the <att>value</att> attribute is
-<code>required</code> or <code>use</code>,
-and if the TTML processor implementation does
-not support the feature, then it must not further process the document
-without the presence of an explicit override from an end-user or some
-implementation specific parameter traceable to an end-user or to a
-user or system configuration setting.  If a TTML processor aborts
-processing of a TTML document instance due to the specification of a
-required, but unsupported feature by this element, then some end-user
-notification should be given unless the end-user or system has
-disabled such a notification, or if the processor does not permit or
-entail the intervention of an end-user.</p>
-<p>If the value of the <att>value</att> attribute is
-<code>optional</code>, and if the TTML processor implementation does
-not support the feature, then it may further process the document even
-in the case that some use of the feature is present in the document.
-In the case of actual use of a feature designated as optional, the
-default semantics associated with that feature apply; that is, the
-processor may behave as if the feature were not actually used or
-referenced by the document. Notwithstanding the above, the syntactic
-presence or reference to an optional feature by a document must not be
-considered to be a violation of document validity or a barrier to
-further processing if the syntactic expression is well-formed and
-valid.</p>
-<p>The <el>ttp:feature</el> element is illustrated by the following example.</p>
-<table id="parameter-vocabulary-feature-example-1" role="example">
-<caption>Example Fragment &ndash; ttp:feature</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;ttp:profile use="http://www.w3.org/ns/ttml/profile/dfxp-presentation"&gt;
-  &lt;ttp:features xml:base="http://www.w3.org/ns/ttml/feature/"&gt;
-    <phrase role="strong">&lt;ttp:feature value="required"&gt;#fontStyle-italic&lt;/ttp:feature&gt;</phrase>
-    <phrase role="strong">&lt;ttp:feature value="required"&gt;#textDecoration-under&lt;/ttp:feature&gt;</phrase>
-  &lt;/ttp:features&gt;
-&lt;/ttp:profile&gt;
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<note role="explanation">
-<p>In the above example, the DFXP presentation profile is used as the
-baseline profile. This baseline profile is then modified by two
-<el>ttp:feature</el> elements in order to
-superset the baseline profile (since neither
-<code>#fontStyle-italic</code> nor <code>#textDecoration-under</code>
-are required by the DFXP presentation profile).  
-<!-- removed text:
-Note that
-the explicit specification of <code>required</code> on the
-<att>value</att> attribute on these two
-<el>ttp:feature</el> elements is not strictly
-necessary, since it is the default value of this
-attribute.--></p> 
-<p>The effect of this example is to express authorial intentions that
-italic font style and text underlining must be
-supported.</p>
-</note>
-</div3>
-<div3 id="parameter-vocabulary-extensions">
-<head>ttp:extensions</head>
-<p>The <el>ttp:extensions</el> element is a container element used to group
-infomation about extension support requirements.</p>
-<p>The <el>ttp:extensions</el> element accepts as its children zero or more
-elements in the <code>Metadata.class</code> element group, followed by
-zero or more <el>ttp:extension</el> elements.</p>
-<table id="elt-syntax-parameter-extensions" role="syntax">
-<caption>XML Representation &ndash; Element Information Item: ttp:extensions</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;ttp:extensions
-  xml:base = string : <emph>TT Extension Namespace</emph>
-  <loc href="#content-attribute-id">xml:id</loc> = ID
-  {<emph>any attribute not in default or any TT namespace</emph>}&gt;
-  <emph>Content:</emph> <loc href="#element-vocab-group-table">Metadata.class</loc>*, <loc href="#parameter-vocabulary-extension">ttp:extension</loc>*
-&lt;/ttp:extensions&gt;
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p>If specified, the <att>xml:base</att>
-attribute must (1) adhere to the
-<code>xsd:anyURI</code> data type defined by <bibref ref="xsd-2"/>,
-&sect;3.2.17, (2) express an absolute URI that
-adheres to <bibref ref="xmlbase"/> and,
-(3) express an extension namespace as defined by
-<specref ref="extension-designations"/>. If not specified, the
-<att>xml:base</att> attribute's default
-value applies, which is the TT Extension Namespace.</p>
-<p>The <att>xml:base</att> attribute is
-used to permit the abbreviation of feature designation URIs expressed
-by child <el>ttp:extension</el> elements.</p>
-</div3>
-<div3 id="parameter-vocabulary-extension">
-<head>ttp:extension</head>
-<p>The <el>ttp:extension</el> element is used to specify
-infomation about support requirements for a particular extension.</p>
-<p>The children of the <el>ttp:extension</el> element must express a non-empty
-sequence of character information items that adheres to the
-<code>xsd:anyURI</code> data type defined by <bibref ref="xsd-2"/>,
-&sect;3.2.17.</p>
-<table id="elt-syntax-parameter-extension" role="syntax">
-<caption>XML Representation &ndash; Element Information Item: ttp:extension</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;ttp:extension
-  value = (optional|required|use) : required
-  <loc href="#content-attribute-id">xml:id</loc> = ID
-  {<emph>any attribute not in default or any TT namespace</emph>}&gt;
-  <emph>Content:</emph> #PCDATA
-&lt;/ttp:extension&gt;
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p>If the URI expressed by the content of the <el>ttp:extension</el>
-element is a relative URI, then, when combined with the
-extension namespace value expressed by the
-<att>xml:base</att> attribute of the
-nearest ancestor <el>ttp:extensions</el> element, it must express an
-absolute URI.  In either case (original absolute URI or resulting
-absolutized URI), the URI expressed by the <el>ttp:extension</el>
-element must further adhere to the syntax of an extension designation
-as defined by <specref ref="extension-designations"/>.</p>
-<p>If the URI expressed by the content of the
-<el>ttp:feature</el> element is a relative URI, then an
-<att>xml:base</att> attribute should be specified on the nearest
-ancestor <el>ttp:extensions</el> element.</p>
-<p>The <att>value</att> attribute specifies whether a conforming TTML
-processor must or may implement the designated extension in order to
-process the document. If the value of the <att>value</att> attribute
-is <code>optional</code>, then the processor need
-not implement or otherwise support the extension in order to process the
-document; if the value is <code>required</code>, then the processor
-must implement or otherwise support the extension in order to process
-the document; if the value is
-<code>use</code>, then the processor must both (1) implement or
-otherwise support the extension and (2) enable (activate) use of the
-extension.</p>
-<note role="clarification">
-<p>The default value of the <att>value</att> attribute is
-<code>required</code>, as indicated in the above element information
-item definition. Therefore, if a <att>value</att> attribute is not
-specified on a <el>ttp:extension</el> element, it is equivalent to
-specifying that support for the extension is required.</p>
-</note>
-<p>If the value of the <att>value</att> attribute is
-<code>required</code> or <code>use</code>,
-and if the TTML processor implementation does not support the
-extension, then it must not further process the document without the
-presence of an explicit override from an end-user or some
-implementation specific parameter traceable to an end-user or to a
-user or system configuration setting.  If a TTML processor aborts
-processing of a TTML document instance due to the specification of a
-required, but unsupported extension by this element, then some
-end-user notification should be given unless the end-user or system
-has disabled such a notification, or if the processor does not permit
-or entail the intervention of an end-user.</p>
-<p>If the value of the <att>value</att> attribute is
-<code>optional</code>, and if the TTML processor implementation does
-not support the extension, then it may further process the document even
-in the case that some use of the extension is present in the document.
-In the case of actual use of an extension designated as optional, the
-default semantics associated with that extension apply; that is, the
-processor may behave as if the extension were not actually used or
-referenced by the document. Notwithstanding the above, the syntactic
-presence or reference to an optional extension by a document must not be
-considered to be a violation of document validity or a barrier to
-further processing if the syntactic expression is well-formed and
-valid.</p>
-<p>The <el>ttp:extension</el> element is illustrated by the following example.</p>
-<table id="parameter-vocabulary-extension-example-1" role="example">
-<caption>Example Fragment &ndash; ttp:extension</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;ttp:profile use="http://www.w3.org/ns/ttml/profile/dfxp-transformation"&gt;
-  &lt;ttp:extensions xml:base="http://foo.bar.example.org/ttaf1/extension/"&gt;
-    <phrase role="strong">&lt;ttp:extension value="use"&gt;#prefilter-by-language&lt;/ttp:extension&gt;</phrase>
-  &lt;/ttp:extensions&gt;
-&lt;/ttp:profile&gt;
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<note role="explanation">
-<p>In the above example, the DFXP transformation profile is used as
-the baseline profile. This baseline profile is then supersetted by
-specifying that support and use is required for a private extension
-defined in a third party namespace.</p>
-<p>The effect of this example is to express authorial intentions that
-a recipient processor must support the DFXP transformation profile and
-must also support and use an extension defined by a third party.</p>
-</note>
-</div3>
-</div2>
-<div2 id="parameter-attribute-vocabulary">
-<head>Parameter Attribute Vocabulary</head>
-<p>The following attributes are defined in the TT Parameter Namespace.</p>
-<ulist>
-<item><p><specref ref="parameter-attribute-cellResolution"/></p></item>
-<item><p><specref ref="parameter-attribute-clockMode"/></p></item>
-<item><p><specref ref="parameter-attribute-dropMode"/></p></item>
-<item><p><specref ref="parameter-attribute-frameRate"/></p></item>
-<item><p><specref ref="parameter-attribute-frameRateMultiplier"/></p></item>
-<item><p><specref ref="parameter-attribute-markerMode"/></p></item>
-<item><p><specref ref="parameter-attribute-pixelAspectRatio"/></p></item>
-<item><p><specref ref="parameter-attribute-profile"/></p></item>
-<item><p><specref ref="parameter-attribute-subFrameRate"/></p></item>
-<item><p><specref ref="parameter-attribute-tickRate"/></p></item>
-<item><p><specref ref="parameter-attribute-timeBase"/></p></item>
-</ulist>
-<p>Unless explicitly stated otherwise, linear white-space (LWSP) may
-appear between tokens of a value of a TT Parameter.</p>
-<div3 id="parameter-attribute-cellResolution">
-<head>ttp:cellResolution</head>
-<p>The <att>ttp:cellResolution</att> attribute may be used by an author
-to express the number of horizontal and vertical cells into which the root container region
-area is divided for the purpose of expressing presentation semantics in terms of
-a uniform grid.</p>
-<p>If specified, the value of this attribute must adhere to the following syntax:</p>
-<table id="parameter-attribute-cellResolution-syntax" role="syntax">
-<caption>Syntax Representation &ndash; ttp:cellResolution</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-ttp:cellResolution
-  : columns rows                            // <emph>columns</emph> != 0; <emph>rows</emph> != 0
-
-columns | rows
-  : <loc href="#style-value-digit">&lt;digit&gt;</loc>+
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p>If not specified, the number of columns and rows must be considered
-to be 32 and 15, respectively. If specified, then columns or rows must not be zero (0).</p>
-<note role="motivation">
-<p>The choice of values 32 and 15 are based on this being the
-maximum number of columns and rows defined by <bibref
-ref="cea608c"/>.</p>
-</note>
-<p>A <att>ttp:cellResolution</att> attribute is considered to be significant only
-when specified on the <el>tt</el> element.</p>
-<note role="explanation">
-<p>The use of a uniform grid is employed only for the purpose of
-measuring lengths and expressing coordinates. In particular, it is not
-assumed that the presentation of text or the alignment of individual
-glyph areas is
-coordinated with this grid. Such alignment is possible, but
-requires the use of a monospaced font and a font size whose EM square exactly
-matches the cell size.</p>
-</note>
-</div3>
-<div3 id="parameter-attribute-clockMode">
-<head>ttp:clockMode</head>
-<p>The <att>ttp:clockMode</att> attribute is used to specify the
-interpretation of time expressions as real-time time coordinates when
-operating with time base of <code>clock</code> as defined by <specref
-ref="parameter-attribute-timeBase"/>.</p>
-<note role="explanation">
-<p>See <specref ref="timing-time-value-expressions"/> for the
-specification of time expression syntax.</p>
-</note>
-<p>If specified, the value of this attribute must adhere to the following syntax:</p>
-<table id="parameter-attribute-clockMode-syntax" role="syntax">
-<caption>Syntax Representation &ndash; ttp:clockMode</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-ttp:clockMode
-  : "local"
-  | "gps"
-  | "utc"
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p>If the time base, defined by <specref
-ref="parameter-attribute-timeBase"/>, is designated as
-<code>clock</code>, then this parameter applies as follows: if the
-parameter's value is <code>local</code>, then time expressions are
-interpreted as local wall-clock time coordinates;
-if <code>utc</code>, then time expressions are
-interpreted as UTC time coordinates
-<bibref ref="utc"/>;
-if <code>gps</code>, then time expressions are
-interpreted as GPS time coordinates
-<bibref ref="gps"/>.</p>
-<note role="explanation">
-<p>The primary difference between GPS time and UTC time is that GPS
-time is not adjusted for leap seconds, while UTC time is adjusted as
-follows: UTC = TAI (<emph>Temp Atomique International</emph>) + <emph>leap seconds
-accumulated since 1972</emph>. TAI is maintained by the <emph>Bureau
-International des Poids et Mesures</emph> (BIPM) in Sevres, France.
-The GPS system time is steered to a Master Clock (MC) at the US Naval
-Observatory which is kept within a close but unspecified
-tolerance of TAI.</p>
-</note>
-<p>If not specified, the value of this parameter must be considered
-to be <code>utc</code>.</p>
-<p>A <att>ttp:clockMode</att> attribute is considered to be significant only
-when specified on the <el>tt</el> element.</p>
-</div3>
-<div3 id="parameter-attribute-dropMode">
-<head>ttp:dropMode</head>
-<p>The <att>ttp:dropMode</att> attribute is used to specify
-constraints on the interpretation and use of frame counts
-that correspond with <bibref ref="smpte12m"/> time coordinates when operating
-with time base of <code>smpte</code> as defined by
-<specref ref="parameter-attribute-timeBase"/>.</p>
-<p>If specified, the value of this attribute must adhere to the following syntax:</p>
-<table id="parameter-attribute-dropMode-syntax" role="syntax">
-<caption>Syntax Representation &ndash; ttp:dropMode</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-ttp:dropMode
-  : "dropNTSC"
-  | "dropPAL"
-  | "nonDrop"
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p>If the time base, defined by <specref
-ref="parameter-attribute-timeBase"/>, is designated as
-<code>smpte</code>, then this parameter applies as follows: if the
-parameter's value is <code>nonDrop</code>, then, within any given
-second of a time expression, frames count from 0 to
-<emph>N&minus;1</emph>, where <emph>N</emph> is the value specified by
-the <att>ttp:frameRate</att> parameter, but while ignoring any value
-specified by the <att>ttp:frameRateMultiplier</att> parameter.</p>
-<note role="clarification"> <p>When operating in <code>nonDrop</code>
-mode, a second of a time expression may or may not be equal to a
-second of real time during normal (1x speed) forward playback. If the
-<att>ttp:frameRateMultiplier</att> parameter is specified and is not
-equal to 1:1, then a second of a time expression will either be
-shorter or longer than a second of elapsed play in real
-time.</p></note>
-<p>If this parameter's value is <code>dropNTSC</code>, then, within any
-given second of a time expression except the second <code>00</code>,
-frames count from 0 to <emph>N&minus;1</emph>, where <emph>N</emph> is
-the value specified by the <att>ttp:frameRate</att> parameter, but
-while ignoring any value specified by the
-<att>ttp:frameRateMultiplier</att> parameter. If the second of a time
-expression is <code>00</code> and the minute of the time expression is
-not <code>00</code>, <code>10</code>, <code>20</code>, <code>30</code>,
-<code>40</code>, or <code>50</code>, then frame codes <code>00</code>
-and <code>01</code> are dropped during that second; otherwise, these
-frame codes are not dropped.</p>
-<note role="example"> <p>For example, when operating in <code>dropNTSC</code>
-mode with <att>ttp:frameRate</att> of <code>30</code>, a discontinuity
-in frame count occurs between consecutive frames as shown in the
-following sequence of time expressions: <code>01:08:59:28</code>,
-<code>01:08:59:29</code>, <code>01:09:00:02</code>,
-<code>01:09:00:03</code>.</p></note>
-<p>If this parameter's value is <code>dropPAL</code>, then, within any
-given second of a time expression except the second <code>00</code>,
-frames count from 0 to <emph>N&minus;1</emph>, where <emph>N</emph> is
-the value specified by the <att>ttp:frameRate</att> parameter, but
-while ignoring any value specified by the
-<att>ttp:frameRateMultiplier</att> parameter. If the second of a time
-expression is <code>00</code> and the minute of the time expression is
-even but not <code>00</code>, <code>20</code>, or <code>40</code>,
-then frame codes <code>00</code> through <code>03</code> are dropped
-during that second; otherwise, these frame codes are not dropped.</p>
-<note role="example"><p>For example, when operating in <code>dropPAL</code>
-mode with <att>ttp:frameRate</att> of <code>30</code>, a discontinuity
-in frame count occurs between consecutive frames as shown in the
-following sequence of time expressions: <code>01:09:59:28</code>,
-<code>01:09:59:29</code>, <code>01:10:00:04</code>,
-<code>01:10:00:04</code>.</p></note>
-<note role="explanation">
-<p>The <code>dropPAL</code> mode is also known as the
-<emph>M/PAL</emph> or <emph>PAL (M)</emph> drop-frame
-code, which uses PAL modulation with the NTSC frame rate of ~29.97
-frames/second. The M/PAL system is used primarily in Brazil.</p>
-</note>
-<p>If not specified, then <code>nonDrop</code> must be assumed to apply.</p>
-<p>A <att>ttp:dropMode</att> attribute is considered to be significant only
-when specified on the <el>tt</el> element.</p>
-</div3>
-<div3 id="parameter-attribute-frameRate">
-<head>ttp:frameRate</head>
-<p>The <att>ttp:frameRate</att> attribute is used to specify the frame rate of a related
-media object or the intrinsic frame rate of a document instance in case it is intended
-to function as an independent media object.</p>
-<p>If specified, the value of this attribute must adhere to the following syntax:</p>
-<table id="parameter-attribute-frameRate-syntax" role="syntax">
-<caption>Syntax Representation &ndash; ttp:frameRate</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-ttp:frameRate
-  : <loc href="#style-value-digit">&lt;digit&gt;</loc>+                                // <emph>value</emph> > 0
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p>The frame rate that applies to a document instance is used to
-interpret time expressions that are expressed in <emph>frames</emph>
-as defined by <specref ref="timing-value-timeExpression"/>.</p>
-<p>A frame is interpreted as a division of a second of media
-time, such that if the frame rate is specified as <emph>F</emph>, then
-a second of media time is divided into <emph>F</emph> intervals of
-equal duration, where each interval is labeled as frame <emph>f</emph>,
-with <emph>f</emph> &isin; [0&hellip;<emph>F&minus;1</emph>].</p>
-<p>If not specified, the frame rate must be considered to be equal to some
-application defined frame rate, or if no application defined frame rate applies,
-then thirty (30) frames per second. If specified, then the frame rate must
-be greater than zero (0).</p>
-<p>A <att>ttp:frameRate</att> attribute is considered to be significant only
-when specified on the <el>tt</el> element.</p>
-</div3>
-<div3 id="parameter-attribute-frameRateMultiplier">
-<head>ttp:frameRateMultiplier</head>
-<p>The <att>ttp:frameRateMultiplier</att> attribute is used to
-specify a multiplier to be applied to the frame rate specified by a
-<att>ttp:frameRate</att> attribute in order to compute the effective
-frame rate.</p>
-<p>If specified, the value of this attribute must adhere to the following syntax:</p>
-<table id="parameter-attribute-frameRateMultiplier-syntax" role="syntax">
-<caption>Syntax Representation &ndash; ttp:frameRateMultiplier</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-ttp:frameRateMultiplier
-  : numerator denominator                   // <emph>numerator</emph> != 0; <emph>denominator</emph> != 0
-
-numerator | denominator
-  : <loc href="#style-value-digit">&lt;digit&gt;</loc>+
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p>A frame rate multiplier is used when the desired frame rate cannot
-be expressed as an integral number of frames per second.</p>
-<p>If not specified, the frame rate multiplier must be considered to be equal to one (1:1).
-Both numerator and denominator must be non-zero.</p>
-<p>A <att>ttp:frameRateMultiplier</att> attribute is considered to be significant only
-when specified on the <el>tt</el> element.</p>
-<note role="example">
-<p>The frame rate multiplier used for synchronizing with NTSC <bibref
-ref="smpte170m"/>
-formatted video objects at 30 frames per second is nominally
-1000:1001. The nominal frame rate of NTSC video is defined as the chrominance
-sub-carrier frequency of 3,579,545.45&hellip;Hz (= 5.0MHz &mult; 63/88) times the ratio 2/455 divided by
-the number of horizontal lines per frame of 525, which yields a frame
-rate of 29.970029970029&hellip; (= 30 &mult; 1000/1001) frames per
-second. Other frame rate multipliers apply to different regions of
-usage and video format standards.</p>
-</note>
-<note role="example">
-<p>Except in the case of PAL/M, the frame rate multiplier used for synchronizing with PAL
-formatted video objects at 25 frames per second is nominally 1:1.</p>
-</note>
-</div3>
-<div3 id="parameter-attribute-markerMode">
-<head>ttp:markerMode</head>
-<p>The <att>ttp:markerMode</att> attribute is used to specify
-constraints on the interpretation and use of time expressions
-that correspond with <bibref ref="smpte12m"/> time coordinates when operating
-with time base of <code>smpte</code> as defined by
-<specref ref="parameter-attribute-timeBase"/>.</p>
-<p>If specified, the value of this attribute must adhere to the following syntax:</p>
-<table id="parameter-attribute-markerMode-syntax" role="syntax">
-<caption>Syntax Representation &ndash; ttp:markerMode</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-ttp:markerMode
-  : "continuous"
-  | "discontinuous"
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p>If the time base, defined by <specref
-ref="parameter-attribute-timeBase"/>, is designated as
-<code>smpte</code>, then this parameter applies as follows: if the
-parameter's value is <code>continuous</code>, then <bibref ref="smpte12m"/> time coordinates
-may be assumed to be linear and either monotonically increasing or
-decreasing; however, if <code>discontinuous</code>, then any assumption
-must not be made regarding linearity or monotonicity of time coordinates.</p>
-<p>If not specified, the value of this parameter must be considered
-to be <code>continuous</code>.</p>
-<p>A <att>ttp:markerMode</att> attribute is considered to be significant only
-when specified on the <el>tt</el> element.</p>
-<p>If a value of <code>discontinuous</code> applies, then time
-expressions must not be converted to either media time or real time
-coordinates, arithmetical operators (addition, multiplication) are not
-defined on time expressions, and, consequently, any expression of a
-duration must be considered to be invalid.</p>
-<note role="explanation">
-<p>When operating with <code>smpte</code> time base and
-<code>discontinuous</code> marker mode, there is no effective time coordinate
-space; rather, all time expressions are interpreted as labeled
-synchronization events (markers), where some external synchronization
-context emits these events, which, when they correspond with time
-expressions that denote the same label, cause a temporal interval to
-begin or end accordingly.</p>
-<p>An additional side-effect of operating in <code>discontinuous</code>
-mode is that time expressions of children have no necessary
-relationship with time expressions of their temporal container; that
-is, temporal containers and children of these containers are
-temporally activated and inactivated independently based on the
-occurrence of a labeled synchronization (marker) event.</p>
-</note>
-<note role="explanation">
-<p>The notion of marker discontinuity as captured by this parameter
-is logically independent from the method used to count frames as
-expressed by the <att>ttp:dropMode</att> parameter. In particular,
-even if the <att>ttp:dropMode</att> parameter is specified as
-<code>dropNTSC</code> or <code>dropPAL</code>, the marker mode may be
-specified as <code>continuous</code>, even in the presence of frame count
-discontinuities induced by the frame counting method, unless there
-were some other non-linearity or discontinuity in marker labeling, for
-example, two consecutive frames labeled as <code>10:00:00:00</code>
-and <code>10:00:01:00</code>.
-</p>
-</note>
-</div3>
-<div3 id="parameter-attribute-pixelAspectRatio">
-<head>ttp:pixelAspectRatio</head>
-<p>The <att>ttp:pixelAspectRatio</att> attribute may be used by a content author
-to express the aspect ratio of non-square pixels in the production of content that
-makes use of pixel coordinates.</p>
-<p>If specified, the value of this attribute must adhere to the following syntax:</p>
-<table id="parameter-attribute-pixelAspectRatio-syntax" role="syntax">
-<caption>Syntax Representation &ndash; ttp:pixelAspectRatio</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-ttp:pixelAspectRatio
-  : width height                            // <emph>width</emph> != 0; <emph>height</emph> != 0
-
-width | height
-  : <loc href="#style-value-digit">&lt;digit&gt;</loc>+
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p>If not specified, then square pixels (i.e., aspect ratio 1:1) must be assumed to apply.
-If specified, then both width and height must be non-zero.</p>
-<p>A <att>ttp:pixelAspectRatio</att> attribute is considered to be significant only
-when specified on the <el>tt</el> element.</p>
-<note role="explanation">
-<p>This parameter may be used by a content transcoder or translator in
-order to convert pixel measurements between different pixel aspect
-ratios while still maintaining authorial layout intentions.</p>
-</note>
-</div3>
-<div3 id="parameter-attribute-profile">
-<head>ttp:profile</head>
-<p>The <att>ttp:profile</att> attribute may be used by a content author
-to express the profile of the Timed Text Markup Language (TTML) used
-in a document instance.</p>
-<p>If specified, the value of this attribute must adhere to the
-<code>xsd:anyURI</code> data type defined by <bibref ref="xsd-2"/>,
-&sect;3.2.17, and, further, must specify a
-profile designator in accordance with
-<specref ref="vocabulary-profiles"/>.</p>
-<p>A <att>ttp:profile</att>
-attribute is considered to be significant only when specified on the
-<el>tt</el> element.</p>
-</div3>
-<div3 id="parameter-attribute-subFrameRate">
-<head>ttp:subFrameRate</head>
-<p>The <att>ttp:subFrameRate</att> attribute is used to specify the sub-frame rate of a related
-media object or the intrinsic sub-frame rate of a document instance in case it is intended
-to function as an independent media object.</p>
-<p>If specified, the value of this attribute must adhere to the following syntax:</p>
-<table id="parameter-attribute-subFrameRate-syntax" role="syntax">
-<caption>Syntax Representation &ndash; ttp:subFrameRate</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-ttp:subFrameRate
-  : <loc href="#style-value-digit">&lt;digit&gt;</loc>+                                // <emph>value</emph> > 0
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p>The sub-frame rate that applies to a document instance is used to
-interpret time expressions that are expressed in <emph>sub-frames</emph>
-as defined by <specref ref="timing-value-timeExpression"/>.</p>
-<p>A sub-frame is interpreted as a division of a frame of media
-time, such that if the sub-frame rate is specified as <emph>S</emph>, then
-a frame of media time is divided into <emph>S</emph> intervals of
-equal duration, where each interval is labeled as sub-frame <emph>s</emph>,
-with <emph>s</emph> &isin; [0&hellip;<emph>S&minus;1</emph>].</p>
-<p>If not specified, the sub-frame rate must be considered to be
-equal to one (1). If specified, then the sub-frame rate must be greater than zero (0).</p>
-<p>A <att>ttp:subFrameRate</att> attribute is considered to be significant only
-when specified on the <el>tt</el> element.</p>
-<note role="clarification">
-<p>The sub-frame is sometimes referred to as a <emph>field</emph> in
-the context of synchronization with an interlaced video media object.</p>
-</note>
-</div3>
-<div3 id="parameter-attribute-tickRate">
-<head>ttp:tickRate</head>
-<p>The <att>ttp:tickRate</att> attribute is used to specify the tick rate of a related
-media object or the intrinsic tick rate of content of a document instance in case it is intended
-to function as an independent media object.</p>
-<p>If specified, the value of this attribute must adhere to the following syntax:</p>
-<table id="parameter-attribute-tickRate-syntax" role="syntax">
-<caption>Syntax Representation &ndash; ttp:tickRate</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-ttp:tickRate
-  : <loc href="#style-value-digit">&lt;digit&gt;</loc>+                                // <emph>value</emph> > 0
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p>The tick rate that applies to a document instance is used to
-interpret time expressions that are expressed in <emph>ticks</emph> by
-using the <code>t</code> metric as defined by <specref
-ref="timing-value-timeExpression"/>.</p>
-<p>A tick is interpreted as an integral division of a second of media
-time, such that if the tick rate is specified as <emph>T</emph>, then
-a second of media time is divided into <emph>T</emph> intervals of
-equal duration, where each interval is labeled as tick <emph>t</emph>,
-with <emph>t</emph> &isin; [0&hellip;<emph>T&minus;1</emph>].</p>
-<p>If not specified, then if a frame rate is specified, the tick rate
-must be considered to be the effective frame rate multiplied by the
-sub-frame rate (i.e., ticks are interpreted as sub-frames); or, if no
-frame rate is specified, the tick rate must be considered to be one (1)
-tick per second of media time. If specified, then the tick rate
-must not be zero (0).</p>
-<note role="clarification">
-<p>There is no predefined relationship between ticks and frames or
-sub-frames. Ticks are an arbitrary division of seconds that permit
-use of fixed point arithmetic rather than fractional (and potentially
-inexact) expressions of seconds.</p>
-</note>
-<p>A <att>ttp:tickRate</att> attribute is considered to be significant only
-when specified on the <el>tt</el> element.</p>
-</div3>
-<div3 id="parameter-attribute-timeBase">
-<head>ttp:timeBase</head>
-<p>The <att>ttp:timeBase</att> attribute is used to specify the
-temporal coordinate system by means of which time expressions are
-interpreted in a document instance.</p>
-<p>If specified, the value of this attribute must adhere to the following syntax:</p>
-<table id="parameter-attribute-timeBase-syntax" role="syntax">
-<caption>Syntax Representation &ndash; ttp:timeBase</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-ttp:timeBase
-  : "media"
-  | "smpte"
-  | "clock"
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p>If the time base is designated as <code>media</code>, then a time
-expression denotes a coordinate in some media object's time line,
-where the media object may be an external media object with which the
-content of a document instance is to be synchronized, or it may
-be the content of a document instance itself in a case where
-the timed text content is intended to establish an independent time
-line.</p>
-<note role="explanation">
-<p>When using a media time base, if that time base is paused or
-scaled positively or negatively, then it is expected that the
-presentation of associated Timed Text content will be similarly
-paused, accelerated, or decelerated, respectively. The means for
-controlling an external
-media time base is outside the scope of this specification.</p>
-</note>
-<p>If the time base is designated as <code>smpte</code>,
-then a time expression denotes a <bibref ref="smpte12m"/> time
-coordinate with which the content of a document instance is to
-be synchronized.  In this case, the value of the <att>ttp:markerMode</att> 
-and <att>ttp:dropMode</att> parameters apply, as defined by <specref
-ref="parameter-attribute-markerMode"/> and <specref
-ref="parameter-attribute-dropMode"/>, respectively.</p>
-<p>If the time base is designated as <code>clock</code>, then the time
-expression denotes a coordinate in some real-world time line as
-established by some real-time clock, such as the local wall-clock time
-or UTC (Coordinated Universal Time) or GPS (Global Positioning System)
-time lines.</p>
-<p>If not specified, the default time base must be considered to be
-<code>media</code>.</p>
-<p>A <att>ttp:timeBase</att> attribute is considered to be significant only
-when specified on the <el>tt</el> element.</p>
-<p>When operating with either <code>media</code> or <code>smpte</code>
-time bases, a diachronic presentation of a document instance may
-be subject to transformations of the controlling time line, such as
-temporal reversal, dilation (expansion), or constriction
-(compression); however, when operating with the <code>clock</code>
-time base, no transformations are permitted, and diachronic
-presentation proceeds on a linear, monotonically increasing time line
-based on the passage of real time.</p>
-<note role="example">
-<p>Due to there being only one time base parameter that applies to a
-given document instance, the interpretation of time expressions
-is uniform throughout the document instance.</p>
-</note>
-<p>When operating with the <code>clock</code> time base,
-the expression <emph>media time</emph> as used in this specification is
-to be interpreted as the real-time clock selected by
-<specref ref="parameter-attribute-clockMode"/>.</p>
-</div3>
-</div2>
-</div1>
-<div1 id="content">
-<head>Content</head>
-<p>This section specifies the <emph>content</emph> matter of the core
-vocabulary catalog.</p>
-<div2 id="content-element-vocabulary">
-<head>Content Element Vocabulary</head>
-<p>The following elements specify the structure and principal content aspects of a
-document instance:</p>
-<ulist>
-<item><p><specref ref="document-structure-vocabulary-tt"/></p></item>
-<item><p><specref ref="document-structure-vocabulary-head"/></p></item>
-<item><p><specref ref="document-structure-vocabulary-body"/></p></item>
-<item><p><specref ref="content-vocabulary-div"/></p></item>
-<item><p><specref ref="content-vocabulary-p"/></p></item>
-<item><p><specref ref="content-vocabulary-span"/></p></item>
-<item><p><specref ref="content-vocabulary-br"/></p></item>
-</ulist>
-<div3 id="document-structure-vocabulary-tt">
-<head>tt</head>
-<p>The <el>tt</el> element serves as the root document element of a document
-instance.</p>
-<p>The <el>tt</el> element accepts as its children zero or one <el>head</el> element followed by
-zero or one <el>body</el> element.</p>
-<table id="elt-syntax-tt" role="syntax">
-<caption>XML Representation &ndash; Element Information Item: tt</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;tt
-  <loc href="#style-attribute-extent">tts:extent</loc> = string
-  <loc href="#content-attribute-id">xml:id</loc> = ID
-  <loc href="#content-attribute-lang"><phrase role="reqattr">xml:lang</phrase></loc> = string
-  <loc href="#content-attribute-space">xml:space</loc> = (<emph>default</emph>|<emph>preserve</emph>) : default
-  {<emph>any attribute in TT Parameter namespace</emph>}
-  {<emph>any attribute not in default or any TT namespace</emph>}&gt;
-  <emph>Content:</emph> <loc href="#document-structure-vocabulary-head">head</loc>?, <loc href="#document-structure-vocabulary-body">body</loc>?
-&lt;/tt&gt;
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p>The temporal beginning and ending of a document instance represented by a
-<el>tt</el> element is defined in relationship with some external
-application or presentation context. The temporal interval defined by
-these points is referred to subsequently as the <emph>external time interval</emph>.
-</p>
-<p>A document instance has an implicit duration that is equal to the
-implicit duration of the <el>body</el> element of the document, if present, or zero,
-if not present.</p>
-<p>If the <att>tts:extent</att> attribute is specified on the <el>tt</el>
-element, then it must adhere to <specref ref="style-attribute-extent"/>, in which case it
-specifies the spatial extent of the root container region in
-which content regions are located and presented. If no <att>tts:extent</att>
-attribute is specified, then the spatial extent of the root container region is
-considered to be determined by the external authoring or presentation
-context. The root container origin is determined by the external
-authoring context.</p>
-<p>An <att>xml:lang</att> attribute must be specified on the <el>tt</el> element.
-If the attribute value is empty, it signifies that there is no default language that applies
-to the text contained within the document instance.</p>
-<p>If no <att>xml:space</att> attribute is specified upon the <el>tt</el> element, then it must
-be considered as if the attribute had been specified with a value of <code>default</code>.</p>
-</div3>
-<div3 id="document-structure-vocabulary-head">
-<head>head</head>
-<p>The <el>head</el> element is a container element used to group
-header matter, including metadata,
-profile, styling, and layout information.</p>
-<p>The <el>head</el> element accepts as its children zero or more
-elements in the <code>Metadata.class</code> element group,
-followed by zero or more elements in the
-<code>Parameters.class</code> element group,
-followed by zero or one <el>styling</el> element,
-followed by zero or one <el>layout</el> element.</p>
-<p>Any metadata specified by children in the <code>Metadata.class</code>
-element group applies semantically to the document instance as a
-whole, and not just the <el>head</el> element.</p>
-<p>Any parameters specified by children in the <code>Parameters.class</code>
-element group applies semantically to the document instance as a
-whole, and not just the <el>head</el> element.</p>
-<p>A <el>styling</el> child element is used to specify style constructs
-that are referenced from other style constructs, by layout constructs, and by
-content elements.</p>
-<p>A <el>layout</el> child element is used to specify layout constructs that
-are referenced by content elements.</p>
-<table id="elt-syntax-head" role="syntax">
-<caption>XML Representation &ndash; Element Information Item: head</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;head
-  <loc href="#content-attribute-id">xml:id</loc> = ID
-  <loc href="#content-attribute-lang">xml:lang</loc> = string
-  <loc href="#content-attribute-space">xml:space</loc> = (<emph>default</emph>|<emph>preserve</emph>)
-  {<emph>any attribute not in default or any TT namespace</emph>}&gt;
-  <emph>Content:</emph> <loc href="#element-vocab-group-table">Metadata.class</loc>*, <loc href="#element-vocab-group-table">Parameters.class</loc>*, <loc href="#styling-vocabulary-styling">styling</loc>?, <loc href="#layout-vocabulary-layout">layout</loc>?
-&lt;/head&gt;
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p>To the extent that time semantics apply to the content of the
-<el>head</el> element, the implied time interval of this element is
-defined to be coterminous with the external time interval.</p>
-</div3>
-<div3 id="document-structure-vocabulary-body">
-<head>body</head>
-<p>The <el>body</el> element functions as a logical container and a temporal
-structuring element for a sequence of textual content units represented as
-logical divisions.</p>
-<p>The <el>body</el> element accepts as its children zero or more
-elements in the <code>Metadata.class</code> element group,
-followed by zero or more
-elements in the <code>Animation.class</code> element group,
-followed by
-zero or more <el>div</el> elements.</p>
-<p>Any metadata specified by children in the <code>Metadata.class</code>
-element group applies semantically to the <el>body</el> element and its descendants as a whole.</p>
-<p>Any animation elements specified by children in the <code>Animation.class</code>
-element group apply semantically to the <el>body</el> element.</p>
-<table id="elt-syntax-body" role="syntax">
-<caption>XML Representation &ndash; Element Information Item: body</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;body
-  <loc href="#timing-attribute-begin">begin</loc> = <loc href="#timing-value-timeExpression">&lt;timeExpression&gt;</loc>
-  <loc href="#timing-attribute-dur">dur</loc> = <loc href="#timing-value-timeExpression">&lt;timeExpression&gt;</loc>
-  <loc href="#timing-attribute-end">end</loc> = <loc href="#timing-value-timeExpression">&lt;timeExpression&gt;</loc>
-  <loc href="#layout-attribute-region">region</loc> = IDREF
-  <loc href="#style-attribute-style">style</loc> = IDREFS
-  <loc href="#timing-attribute-timeContainer">timeContainer</loc> = (<emph>par</emph>|<emph>seq</emph>)
-  <loc href="#content-attribute-id">xml:id</loc> = ID
-  <loc href="#content-attribute-lang">xml:lang</loc> = string
-  <loc href="#content-attribute-space">xml:space</loc> = (<emph>default</emph>|<emph>preserve</emph>)
-  {<emph>any attribute in TT Metadata namespace</emph>}
-  {<emph>any attribute in TT Style namespace</emph>}
-  {<emph>any attribute not in default or any TT namespace</emph>}&gt;
-  <emph>Content:</emph> <loc href="#element-vocab-group-table">Metadata.class</loc>*, <loc href="#element-vocab-group-table">Animation.class</loc>*, <loc href="#content-vocabulary-div">div</loc>*
-&lt;/body&gt;
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p>An author may specify a temporal interval for a <el>body</el> element using
-the <att>begin</att>, <att>dur</att>, and <att>end</att> attributes. If the begin point
-of this interval remains unspecified, then the begin point is interpreted as the begin
-point of the external time interval. Similarly, if the end point of this interval remains unspecified, then the
-end point is interpreted as the end point of the external time interval.</p>
-<note role="explanation">
-<p>A TTML document instance referenced from a SMIL presentation
-is expected to follow the same timing rules as apply to other SMIL media
-objects.</p>
-</note>
-<p>If relative begin or end times are specified on the <el>body</el>
-element, then these times are resolved by reference to the begin and
-end time of the external time interval.</p>
-<p>If the external time interval is shorter than the computed duration of the
-<el>body</el> element, then the active time interval of a document instance is
-truncated to the active end point of the external time interval.</p>
-<p>An author may associate a set of style properties with a
-<el>body</el> element by means of either the <att>style</att>
-attribute or inline style attributes or a combination thereof.</p>
-<note role="explanation">
-<p>Style properties that are associated with a <el>body</el> element
-in a document instance are available for style inheritance by
-descendant content elements such as <el>div</el>, <el>p</el>,
-<el>span</el>
-and <el>br</el>.</p>
-</note>
-<p>If no <att>timeContainer</att> attribute is specified on a
-<el>body</el> element, then it must be interpreted as having
-<emph>parallel</emph>
-time containment semantics.</p>
-</div3>
-<div3 id="content-vocabulary-div">
-<head>div</head>
-<p>The <el>div</el> element functions as a logical container and a temporal
-structuring element for a sequence of textual content units represented as
-logical sub-divisions or paragraphs.</p>
-<note role="explanation">
-<p>When rendered on a continuous (non-paged) visual presentation medium,
-a <el>div</el> element is expected to generate
-one or more block
-areas
-that contain zero or more child block areas
-generated by the <el>div</el> element's
-descendant
-<el>p</el> elements.
-</p>
-<p>If some
-block area generated by a <el>div</el> element does
-not contain any child areas, then it is not expected to be presented.</p>
-</note>
-<p>The <el>div</el> element accepts as its children zero or more
-elements in the <code>Metadata.class</code> element group,
-followed by zero or more
-elements in the <code>Animation.class</code> element group,
-followed by
-zero or more
-<el>div</el> or 
-<el>p</el> elements.</p>
-<p>Any metadata specified by children in the <code>Metadata.class</code>
-element group applies semantically to the <el>div</el> element and its descendants as a whole.</p>
-<p>Any animation elements specified by children in the <code>Animation.class</code>
-element group apply semantically to the <el>div</el> element.</p>
-<table id="elt-syntax-div" role="syntax">
-<caption>XML Representation &ndash; Element Information Item: div</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;div
-  <loc href="#timing-attribute-begin">begin</loc> = <loc href="#timing-value-timeExpression">&lt;timeExpression&gt;</loc>
-  <loc href="#timing-attribute-dur">dur</loc> = <loc href="#timing-value-timeExpression">&lt;timeExpression&gt;</loc>
-  <loc href="#timing-attribute-end">end</loc> = <loc href="#timing-value-timeExpression">&lt;timeExpression&gt;</loc>
-  <loc href="#layout-attribute-region">region</loc> = IDREF
-  <loc href="#style-attribute-style">style</loc> = IDREFS
-  <loc href="#timing-attribute-timeContainer">timeContainer</loc> = (<emph>par</emph>|<emph>seq</emph>)
-  <loc href="#content-attribute-id">xml:id</loc> = ID
-  <loc href="#content-attribute-lang">xml:lang</loc> = string
-  <loc href="#content-attribute-space">xml:space</loc> = (<emph>default</emph>|<emph>preserve</emph>)
-  {<emph>any attribute in TT Metadata namespace</emph>}
-  {<emph>any attribute in TT Style namespace</emph>}
-  {<emph>any attribute not in default or any TT namespace</emph>}&gt;
-  <emph>Content:</emph> <loc
-  href="#element-vocab-group-table">Metadata.class</loc>*, <loc
-  href="#element-vocab-group-table">Animation.class</loc>*, <loc
-  href="#element-vocab-group-table">Block.class</loc>*
-&lt;/div&gt;
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p>An author may associate a set of style properties with a <el>div</el> element by means of either
-the <att>style</att> attribute or inline style attributes or a combination thereof.</p>
-<note role="explanation">
-<p>Style properties that are associated
-with
-a <el>div</el> element in a document instance
-are available for style inheritance by descendant content elements such as
-<el>div</el>, 
-<el>p</el>,
-<el>span</el>, and
-<el>br</el>.</p>
-</note>
-<p>If no <att>timeContainer</att> attribute is specified on
-a <el>div</el> element, then it must be interpreted as having
-<emph>parallel</emph> time containment semantics.</p>
-</div3>
-<div3 id="content-vocabulary-p">
-<head>p</head>
-<p>A <el>p</el> element represents a logical paragraph, serving as
-a transition between block level and inline level formatting semantics.</p>
-<p>The <el>p</el> element accepts as its children zero or more
-elements in the <code>Metadata.class</code> element group,
-followed by zero or more
-elements in the <code>Animation.class</code> element group,
-followed by
-zero or more
-<code>span</code> element,
-<code>br</code> element,
-or text nodes interpreted as anonymous spans.</p>
-<p>Any metadata specified by children in the <code>Metadata.class</code>
-element group applies semantically to the <el>p</el> element and its descendants as a whole.</p>
-<p>Any animation elements specified by children in the <code>Animation.class</code>
-element group apply semantically to the <el>p</el> element.</p>
-<table id="elt-syntax-p" role="syntax">
-<caption>XML Representation &ndash; Element Information Item: p</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;p
-  <loc href="#timing-attribute-begin">begin</loc> = <loc href="#timing-value-timeExpression">&lt;timeExpression&gt;</loc>
-  <loc href="#timing-attribute-dur">dur</loc> = <loc href="#timing-value-timeExpression">&lt;timeExpression&gt;</loc>
-  <loc href="#timing-attribute-end">end</loc> = <loc href="#timing-value-timeExpression">&lt;timeExpression&gt;</loc>
-  <loc href="#layout-attribute-region">region</loc> = IDREF
-  <loc href="#style-attribute-style">style</loc> = IDREFS
-  <loc href="#timing-attribute-timeContainer">timeContainer</loc> = (<emph>par</emph>|<emph>seq</emph>)
-  <loc href="#content-attribute-id">xml:id</loc> = ID
-  <loc href="#content-attribute-lang">xml:lang</loc> = string
-  <loc href="#content-attribute-space">xml:space</loc> = (<emph>default</emph>|<emph>preserve</emph>)
-  {<emph>any attribute in TT Metadata namespace</emph>}
-  {<emph>any attribute in TT Style namespace</emph>}
-  {<emph>any attribute not in default or any TT namespace</emph>}&gt;
-  <emph>Content:</emph> <loc
-  href="#element-vocab-group-table">Metadata.class</loc>*, <loc
-  href="#element-vocab-group-table">Animation.class</loc>*, <loc
-  href="#element-vocab-group-table">Inline.class</loc>*
-&lt;/p&gt;
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p>An author may associate a set of style properties with a
-<el>p</el> element by means of either the <att>style</att>
-attribute or inline style attributes or a combination thereof.</p>
-<note role="explanation">
-<p>Style properties that are associated with a <el>p</el> element
-in a document instance are available for style inheritance by
-descendant content elements such as <el>span</el> and
-<el>br</el>.</p>
-</note>
-<p>If no <att>timeContainer</att> attribute is specified on
-a <el>p</el> element, then it must be interpreted as having
-<emph>parallel</emph> time containment semantics.</p>
-<p>If a sequence of children of a <el>p</el> element
-consists solely of character information items, then that sequence must
-be considered to be an <emph>anonymous span</emph> for the purpose of
-applying style properties that apply to <el>span</el> elements.</p>
-</div3>
-<div3 id="content-vocabulary-span">
-<head>span</head>
-<p>The <el>span</el> element functions as a logical container and a temporal
-structuring element for a sequence of textual content units having inline
-level formatting semantics.</p>
-<p>When presented on a visual medium, a <el>span</el> element is intended to
-generate a sequence of inline areas, each containing one or more glyph areas.</p>
-<p>The <el>span</el> element accepts as its children zero or more
-elements in the <code>Metadata.class</code> element group,
-followed by zero or more
-elements in the <code>Animation.class</code> element group,
-followed by
-zero or more
-<el>span</el> elements,
-<el>br</el> elements,
-or text nodes interpreted as anonymous spans.</p>
-<p>Any metadata specified by children in the <code>Metadata.class</code>
-element group applies semantically to the <el>span</el> element and its descendants as a whole.</p>
-<p>Any animation elements specified by children in the <code>Animation.class</code>
-element group apply semantically to the <el>span</el> element.</p>
-<table id="elt-syntax-span" role="syntax">
-<caption>XML Representation &ndash; Element Information Item: span</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;span
-  <loc href="#timing-attribute-begin">begin</loc> = <loc href="#timing-value-timeExpression">&lt;timeExpression&gt;</loc>
-  <loc href="#timing-attribute-dur">dur</loc> = <loc href="#timing-value-timeExpression">&lt;timeExpression&gt;</loc>
-  <loc href="#timing-attribute-end">end</loc> = <loc href="#timing-value-timeExpression">&lt;timeExpression&gt;</loc>
-  <loc href="#layout-attribute-region">region</loc> = IDREF
-  <loc href="#style-attribute-style">style</loc> = IDREFS
-  <loc href="#timing-attribute-timeContainer">timeContainer</loc> = (<emph>par</emph>|<emph>seq</emph>)
-  <loc href="#content-attribute-id">xml:id</loc> = ID
-  <loc href="#content-attribute-lang">xml:lang</loc> = string
-  <loc href="#content-attribute-space">xml:space</loc> = (<emph>default</emph>|<emph>preserve</emph>)
-  {<emph>any attribute in TT Metadata namespace</emph>}
-  {<emph>any attribute in TT Style namespace</emph>}
-  {<emph>any attribute not in default or any TT namespace</emph>}&gt;
-  <emph>Content:</emph> <loc
-  href="#element-vocab-group-table">Metadata.class</loc>*, <loc
-  href="#element-vocab-group-table">Animation.class</loc>*, <loc
-  href="#element-vocab-group-table">Inline.class</loc>*
-&lt;/span&gt;
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p>An author may associate a set of style properties with a
-<el>span</el> element by means of either the <att>style</att>
-attribute or inline style attributes or a combination thereof.</p>
-<note role="explanation">
-<p>Style properties that are associated with a <el>span</el> element
-in a document instance are available for style inheritance by
-descendant content elements such as <el>span</el> and
-<el>br</el>.</p>
-</note>
-<p>If no <att>timeContainer</att> attribute is specified on
-a <el>span</el> element, then it must be interpreted as having
-<emph>parallel</emph> time containment semantics.</p>
-</div3>
-<div3 id="content-vocabulary-br">
-<head>br</head>
-<p>The <el>br</el> element denotes an explicit line break.</p>
-<table id="elt-syntax-br" role="syntax">
-<caption>XML Representation &ndash; Element Information Item: br</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;br
-  <loc href="#style-attribute-style">style</loc> = IDREFS
-  <loc href="#content-attribute-id">xml:id</loc> = ID
-  <loc href="#content-attribute-lang">xml:lang</loc> = string
-  <loc href="#content-attribute-space">xml:space</loc> = (<emph>default</emph>|<emph>preserve</emph>)
-  {<emph>any attribute in TT Metadata namespace</emph>}
-  {<emph>any attribute in TT Style namespace</emph>}
-  {<emph>any attribute not in default or any TT namespace</emph>}&gt;
-  <emph>Content:</emph> <loc href="#element-vocab-group-table">Metadata.class</loc>*, <loc href="#element-vocab-group-table">Animation.class</loc>*
-&lt;/br&gt;
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p>When presented on a visual medium, the presence of a <el>br</el> element must be
-interpreted as a forced line break.</p>
-<note>
-<p>The visual presentation of a <el>br</el> element is
-intended to produce the same effect as the ASCII control code
-<code>CR</code>
-followed by the control code <code>NL</code> when presented on a teletype device.
-Therefore, two <el>br</el> elements in sequence will produce a
-different effect than a single <el>br</el> element.</p>
-</note>
-</div3>
-</div2>
-<div2 id="content-attribute-vocabulary">
-<head>Content Attribute Vocabulary</head>
-<p>This section defines the following common attributes used with many or all element types
-in the core vocabulary catalog:</p>
-<ulist>
-<item><p><specref ref="content-attribute-id"/></p></item>
-<item><p><specref ref="content-attribute-lang"/></p></item>
-<item><p><specref ref="content-attribute-space"/></p></item>
-</ulist>
-<div3 id="content-attribute-id">
-<head>xml:id</head>
-<p>The <att>xml:id</att> attribute is used as defined by
-<bibref ref="xmlid"/>.</p>
-<p>The <att>xml:id</att> attribute may be used with any element in the
-core vocabulary catalog.</p>
-</div3>
-<div3 id="content-attribute-lang">
-<head>xml:lang</head>
-<p>The <att>xml:lang</att> attribute is used as defined by
-<bibref ref="xml10"/>, &sect;2.12, <emph>Language Identification</emph>.</p>
-<p>The <att>xml:lang</att> attribute must be specified on the <el>tt</el>
-element and may be specified by an instance of any other element type
-in the core vocabulary catalog.</p>
-</div3>
-<div3 id="content-attribute-space">
-<head>xml:space</head>
-<p>The <att>xml:space</att> attribute is used as defined by
-<bibref ref="xml10"/>, &sect;2.10, <emph>White Space Handling</emph>.</p>
-<p>The <att>xml:space</att> attribute may be used with any element in
-the core vocabulary catalog.</p>
-<!-- OLD DEFINITION
-<p>The semantics of the value <code>default</code> are fixed to mean that
-white space that appears in element content as defined by <bibref
-ref="xml10"/>, &sect;3.2.1, must be normalized at the
-application layer during subsequent processing, such as presentation or
-transformation processing, as follows:</p>
-<olist>
-<item><p>replace each TAB character (<code>&amp;#x0009;</code>) and NEWLINE character (<code>&amp;#x000A;</code>) with a SPACE
-character (<code>&amp;#x0020;</code>);</p></item>
-<item><p>replace each sequence of two or more SPACE characters with a
-single SPACE character;</p></item>
-<item><p>for every maximum sequence of sibling character information
-items, if there is a leading or trailing SPACE character in the
-sequence, then remove the character.</p></item>
-</olist>
--->
-<!-- NEW DEFINITION -->
-<p>The semantics of the value <code>default</code> are fixed to mean that
-when performing presentation processing of a document instance as
-described by <specref ref="semantics-region-layout-step-2"/>,
-processing must occur as
-if the following properties were specified on the affected
-<!-- changed for future CSS compatibility
-elements of the intermediate XSL-FO document:</p> 
--->
-elements of an equivalent intermediate XSL-FO document:</p>
-<ulist>
-<item>
-<p><code>suppress-at-line-break="auto"</code></p>
-</item>
-<item>
-<p><code>linefeed-treatment="treat-as-space"</code></p>
-</item>
-<item>
-<p><code>white-space-collapse="true"</code></p>
-</item>
-<item>
-<p><code>white-space-treatment="ignore-if-surrounding-linefeed"</code></p>
-</item>
-</ulist>
-<p>Similarly, the semantics of the value <code>preserve</code> are fixed to mean that
-when performing presentation processing, processing must occur as
-if the following properties were specified on the affected
-<!-- changed for future CSS compatibility
-elements of the intermediate XSL-FO document:</p> 
--->
-elements of an equivalent intermediate XSL-FO document:
-</p>
-<ulist>
-<item>
-<p><code>suppress-at-line-break="retain"</code></p>
-</item>
-<item>
-<p><code>linefeed-treatment="preserve"</code></p>
-</item>
-<item>
-<p><code>white-space-collapse="false"</code></p>
-</item>
-<item>
-<p><code>white-space-treatment="preserve"</code></p>
-</item>
-</ulist>
-<p>When performing other types of processing intended to eventually
-result in a visual presentation by means other than those described
-in this specification, the semantics of space collapsing and
-preservation as described above should be respected. For other types
-of processing, the treatment of the <att>xml:space</att> attribute
-is processor dependent, but should respect the semantics described
-above if possible.</p>
-</div3>
-</div2>
-</div1>
-<div1 id="styling">
-<head>Styling</head>
-<p>This section specifies the <emph>styling</emph> matter of the core
-vocabulary catalog, where
-styling is to be understood as a separable layer of information that applies to
-content and that denotes authorial intentions about the presentation of
-that content.</p>
-  <!-- added for future CSS compatibility -->
-  <p>
-    Styling attributes are included in TTML to enable authorial intent of presentation
-    to be included within a self-contained document. This section describes
-    the semantics of style presentation in terms of a standard processing
-    model. TTML Processors are not required to present TTML documents in any particular way; 
-    but an implementation of this model by a TTML Presentation Processor
-    that provides externally observable results that are consistent with this model is
-    likely to lead to a user experience that closely resembles the experience intended by
-    the documents' authors.
-  </p>
-  <p>
-    The semantics of TTML style presentation are described in terms of the model 
-    in <bibref ref="xsl11"/>. The intended effect of the attributes in this section 
-    are to be compatible with  the layout model of XSL. Presentation agents may however 
-    use any technology to satisfy the authorial intent of the document. In particular 
-    since <bibref ref="css2"/> is a subset of this model, a CSS processor may be used 
-    for the features that the models have in common.
-  </p>
-  <!-- end addition -->
-  <p>No normative use of an
-<code>&lt;?xml-stylesheet ... ?&gt;</code> processing instruction is defined
-by this specification.</p>
-<div2 id="styling-element-vocabulary">
-<head>Styling Element Vocabulary</head>
-<p>The following elements specify the structure and principal styling aspects of a
-document instance:</p>
-<ulist>
-<item><p><specref ref="styling-vocabulary-styling"/></p></item>
-<item><p><specref ref="styling-vocabulary-style"/></p></item>
-</ulist>
-<div3 id="styling-vocabulary-styling">
-<head>styling</head>
-<p>The <el>styling</el> element is a container element used to group
-styling matter, including metadata that applies to styling matter.</p>
-<p>The <el>styling</el> element accepts as its children zero or more
-elements in the <code>Metadata.class</code> element group, followed by
-zero or more <el>style</el> elements.</p>
-<table id="elt-syntax-styling" role="syntax">
-<caption>XML Representation &ndash; Element Information Item: styling</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;styling
-  <loc href="#content-attribute-id">xml:id</loc> = ID
-  <loc href="#content-attribute-lang">xml:lang</loc> = string
-  <loc href="#content-attribute-space">xml:space</loc> = (<emph>default</emph>|<emph>preserve</emph>)
-  {<emph>any attribute not in default or any TT namespace</emph>}&gt;
-  <emph>Content:</emph> <loc href="#element-vocab-group-table">Metadata.class</loc>*, <loc href="#styling-vocabulary-style">style</loc>*
-&lt;/styling&gt;
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p>To the extent that time semantics apply to the content of the
-<el>styling</el> element, the implied time interval of this element is
-defined to be coterminous with the external time interval.</p>
-</div3>
-<div3 id="styling-vocabulary-style">
-<head>style</head>
-<p>The <el>style</el> element is used to define
-a set of style specifications expressed as a
-specified style set in accordance with
-<specref ref="semantics-style-resolution-processing-sss"/>.</p>
-<p>The <el>style</el> element accepts as its children zero or more <el>metadata</el> elements.</p>
-<table id="elt-syntax-style" role="syntax">
-<caption>XML Representation &ndash; Element Information Item: style</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;style
-  <loc href="#style-attribute-style">style</loc> = IDREFS
-  <loc href="#content-attribute-id">xml:id</loc> = ID
-  <loc href="#content-attribute-lang">xml:lang</loc> = string
-  <loc href="#content-attribute-space">xml:space</loc> = (<emph>default</emph>|<emph>preserve</emph>)
-  {<emph>any attribute in TT Style namespace</emph>}
-  {<emph>any attribute not in default or any TT namespace</emph>}&gt;
-  <!-- change for future CSS compatibility
-  <emph>Content:</emph> <loc href="#element-vocab-group-table">Metadata.class</loc>*
-  -->
-  <emph>Content:</emph> EMPTY
-&lt;/style&gt;
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p>If a <el>style</el> element appears as a descendant of a
-<el>region</el> element, then the <el>style</el> element must be
-ignored for the purpose of computing referential styles as defined by
-<specref ref="semantics-style-association-referential"/> and <specref
-ref="semantics-style-association-chained-referential"/>.</p>
-<note role="explanation">
-<p>That is to say, when referential styling is used by an element to
-refer to a <el>style</el> element, then the referenced <el>style</el>
-element must appear as a descendant of the <el>styling</el> element, and
-not in any other context.</p>
-</note>
-</div3>
-</div2>
-<div2 id="styling-attribute-vocabulary">
-<head>Styling Attribute Vocabulary</head>
-<p>This section defines the <specref ref="style-attribute-style"/> attribute used
-with both style definition elements as well as content elements.</p>
-<p>In addition, this section specifies the following attributes in the TT Style Namespace
-for use with style definition elements, certain layout elements, and content elements
-that support inline style specifications:</p>
-<ulist>
-<item><p><specref ref="style-attribute-backgroundColor"/></p></item>
-<item><p><specref ref="style-attribute-color"/></p></item>
-<item><p><specref ref="style-attribute-direction"/></p></item>
-<item><p><specref ref="style-attribute-display"/></p></item>
-<item><p><specref ref="style-attribute-displayAlign"/></p></item>
-<item><p><specref ref="style-attribute-extent"/></p></item>
-<item><p><specref ref="style-attribute-fontFamily"/></p></item>
-<item><p><specref ref="style-attribute-fontSize"/></p></item>
-<item><p><specref ref="style-attribute-fontStyle"/></p></item>
-<item><p><specref ref="style-attribute-fontWeight"/></p></item>
-<item><p><specref ref="style-attribute-lineHeight"/></p></item>
-<item><p><specref ref="style-attribute-opacity"/></p></item>
-<item><p><specref ref="style-attribute-origin"/></p></item>
-<item><p><specref ref="style-attribute-overflow"/></p></item>
-<item><p><specref ref="style-attribute-padding"/></p></item>
-<item><p><specref ref="style-attribute-showBackground"/></p></item>
-<item><p><specref ref="style-attribute-textAlign"/></p></item>
-<item><p><specref ref="style-attribute-textDecoration"/></p></item>
-<item><p><specref ref="style-attribute-textOutline"/></p></item>
-<item><p><specref ref="style-attribute-unicodeBidi"/></p></item>
-<item><p><specref ref="style-attribute-visibility"/></p></item>
-<item><p><specref ref="style-attribute-wrapOption"/></p></item>
-<item><p><specref ref="style-attribute-writingMode"/></p></item>
-<item><p><specref ref="style-attribute-zIndex"/></p></item>
-</ulist>
-<p>Unless explicitly stated otherwise, linear white-space (LWSP) may
-appear between tokens of a value of a TT
-Style or TT Style Extension
-Property.</p>
-<note role="explanation">
-<p>This specification makes use of <emph>lowerCamelCased</emph> local
-names for style attributes that
-are based upon like-named properties defined by <bibref ref="xsl11"/>.
-This convention is likewise extended to token values of such
-properties.</p>
-</note>
-<note role="clarification">
-<p>A style property may be expressed as a specified attribute on any content
-element type independently of whether the property applies to that
-element type. This capability permits the expression of an inheritable
-style property on ancestor elements to which the property
-does not apply.</p>
-</note>
-<div3 id="style-attribute-style">
-<head>style</head>
-<p>The <att>style</att> attribute is used
-by referential style association
-to reference one or more <el>style</el>
-elements each of which define a
-specified
-style set.</p>
-<p>The <att>style</att> attribute may be specified by an instance of the following
-element types:</p>
-<ulist>
-<item><p><loc href="#document-structure-vocabulary-body"><el>body</el></loc></p></item>
-<item><p><loc href="#content-vocabulary-div"><el>div</el></loc></p></item>
-<item><p><loc href="#content-vocabulary-p"><el>p</el></loc></p></item>
-<item><p><loc href="#layout-vocabulary-region"><el>region</el></loc></p></item>
-<item><p><loc href="#content-vocabulary-span"><el>span</el></loc></p></item>
-<item><p><loc href="#styling-vocabulary-style"><el>style</el></loc></p></item>
-</ulist>
-<note role="usage">
-<p>See the specific element type definitions that permit use of the
-<att>style</att> attribute, as well as <specref
-ref="semantics-style-association-referential"/> and <specref
-ref="semantics-style-association-chained-referential"/>, for
-further information on its semantics.</p>
-</note>
-</div3>
-<div3 id="style-attribute-backgroundColor">
-<head>tts:backgroundColor</head>
-<p>The <att>tts:backgroundColor</att> attribute is used to specify a style property that
-defines the background color of a region or an area generated by content flowed into a region.</p>
-<p>This attribute may be specified by any
-element type
-that permits use of attributes in the TT Style Namespace; however, this attribute applies
-as a style property only to those element types indicated in the following table.</p>
-<table id="style-property-details-backgroundColor" role="common">
-<col width="25%"/>
-<tbody>
-<tr>
-<td><emph>Values:</emph></td>
-<td>
-<loc href="#style-value-color">&lt;color&gt;</loc>
-</td>
-</tr>
-<tr>
-<td><emph>Initial:</emph></td>
-<td><code>transparent</code></td>
-</tr>
-<tr>
-<td><emph>Applies to:</emph></td>
-<td>
-<loc href="#document-structure-vocabulary-body"><el>body</el></loc>,
-<loc href="#content-vocabulary-div"><el>div</el></loc>,
-<loc href="#content-vocabulary-p"><el>p</el></loc>,
-<loc href="#layout-vocabulary-region"><el>region</el></loc>,
-<loc href="#content-vocabulary-span"><el>span</el></loc>
-</td>
-</tr>
-<tr>
-<td><emph>Inherited:</emph></td>
-<td>no</td>
-</tr>
-<tr>
-<td><emph>Percentages:</emph></td>
-<td>N/A</td>
-</tr>
-<tr>
-<td><emph>Animatable:</emph></td>
-<td>discrete</td>
-</tr>
-</tbody>
-</table>
-<p>For the purpose of determining applicability of this style property,
-each character child of a <el>p</el> element is considered to be enclosed in an anonymous
-span.</p>
-<p>The <att>tts:backgroundColor</att> style is illustrated by the following example.</p>
-<table id="style-attribute-backgroundColor-example-1" role="example">
-<caption>Example Fragment &ndash; Background Color</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;region xml:id="r1"&gt;
-  &lt;style tts:extent="306px 114px"/&gt;
-  &lt;style <phrase role="strong">tts:backgroundColor="red"</phrase>/&gt;
-  &lt;style tts:color="white"/&gt;
-  &lt;style tts:displayAlign="after"/&gt;
-  &lt;style tts:padding="3px 40px"/&gt;
-&lt;/region&gt;
-...
-&lt;p region="r1" <phrase role="strong">tts:backgroundColor="purple"</phrase> tts:textAlign="center"&gt;
-  Twinkle, twinkle, little bat!&lt;br/&gt;
-  How &lt;span <phrase role="strong">tts:backgroundColor="green"</phrase>&gt;I wonder&lt;/span&gt; where you're at!
-&lt;/p&gt;
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p/>
-<table id="style-attribute-backgroundColor-example-1-images" role="example-images">
-<caption>Example Rendition &ndash; Background Color</caption>
-<tbody>
-<tr>
-<td><graphic source="images/backgroundColor.png" alt="TTML backgroundColor style property"/></td>
-</tr>
-</tbody>
-</table>
-  <!-- CSS compatibility - remove derivation note
-<note role="derivation">
-<p>The semantics of the style property represented by this attribute are based upon 
-that defined by <bibref ref="xsl11"/>, &sect; 7.8.2.</p>
-</note> -->
-  
-</div3>
-<div3 id="style-attribute-color">
-<head>tts:color</head>
-<p>The <att>tts:color</att> attribute is used to specify a style property that
-defines the foreground color of marks associated with an area generated by content flowed into a region.</p>
-<p>This attribute may be specified by any
-element type
-that permits use of attributes in the TT Style Namespace; however, this attribute applies
-as a style property only to those element types indicated in the following table.</p>
-<table id="style-property-details-color" role="common">
-<col width="25%"/>
-<tbody>
-<tr>
-<td><emph>Values:</emph></td>
-<td>
-<loc href="#style-value-color">&lt;color&gt;</loc>
-</td>
-</tr>
-<tr>
-<td><emph>Initial:</emph></td>
-<td>see prose</td>
-</tr>
-<tr>
-<td><emph>Applies to:</emph></td>
-<td>
-<loc href="#content-vocabulary-span"><el>span</el></loc>
-</td>
-</tr>
-<tr>
-<td><emph>Inherited:</emph></td>
-<td>yes</td>
-</tr>
-<tr>
-<td><emph>Percentages:</emph></td>
-<td>N/A</td>
-</tr>
-<tr>
-<td><emph>Animatable:</emph></td>
-<td>discrete</td>
-</tr>
-</tbody>
-</table>
-<p>For the purpose of determining applicability of this style property,
-each character child of a <el>p</el> element is considered to be enclosed in an anonymous
-span.</p>
-<p>The initial value of the <att>tts:color</att> property
-is considered to be implementation dependent. In the absence of
-end-user preference information, a conformant presentation processor
-should use an initial value that is highly contrastive to the
-background color of the root container region.</p>
-<p>The <att>tts:color</att> style is illustrated by the following example.</p>
-<table id="style-attribute-color-example-1" role="example">
-<caption>Example Fragment &ndash; Color</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;region xml:id="r1"&gt;
-  &lt;style tts:backgroundColor="black"/&gt;
-  &lt;style <phrase role="strong">tts:color="white"</phrase>/&gt;
-  &lt;style tts:displayAlign="after"/&gt;
-  &lt;style tts:textAlign="center"/&gt;
-&lt;/region&gt;
-...
-&lt;p region="r1"&gt;
-  In spring, when woods are &lt;span <phrase role="strong">tts:color="green"</phrase>&gt;getting green&lt;/span&gt;,&lt;br/&gt;
-  I'll try and tell you what I mean.
-&lt;/p&gt;
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p/>
-<table id="style-attribute-color-example-1-images" role="example-images">
-<caption>Example Rendition &ndash; Color</caption>
-<tbody>
-<tr>
-<td><graphic source="images/color.png" alt="TTML color style property"/></td>
-</tr>
-</tbody>
-</table>
-  <!-- CSS compatibility - remove derivation note 
-  <note role="derivation">
-<p>The semantics of the style property
-represented by this attribute are based upon that defined by <bibref ref="xsl11"/>,
-&sect; 7.18.1.</p>
-</note>
--->
-</div3>
-<div3 id="style-attribute-direction">
-<head>tts:direction</head>
-<p>The <att>tts:direction</att> attribute is used to specify a style property that
-defines the directionality of an embedding or override according to
-the Unicode bidirectional algorithm.</p>
-<p>This attribute may be specified by any
-element type
-that permits use of attributes in the TT Style Namespace; however, this attribute applies
-as a style property only to those element types indicated in the following table.</p>
-<table id="style-property-details-direction" role="common">
-<col width="25%"/>
-<tbody>
-<tr>
-<td><emph>Values:</emph></td>
-<td>
-<code>ltr</code> |
-<code>rtl</code>
-</td>
-</tr>
-<tr>
-<td><emph>Initial:</emph></td>
-<td>
-<code>ltr</code>
-</td>
-</tr>
-<tr>
-<td><emph>Applies to:</emph></td>
-<td>
-<loc href="#content-vocabulary-p"><el>p</el></loc>,
-<loc href="#content-vocabulary-span"><el>span</el></loc>
-</td>
-</tr>
-<tr>
-<td><emph>Inherited:</emph></td>
-<td>yes</td>
-</tr>
-<tr>
-<td><emph>Percentages:</emph></td>
-<td>N/A</td>
-</tr>
-<tr>
-<td><emph>Animatable:</emph></td>
-<td>discrete</td>
-</tr>
-</tbody>
-</table>
-<p>For the purpose of determining applicability of this style property,
-each character child of a <el>p</el> element is considered to be enclosed in an anonymous
-span.</p>
-<p>If a specified value of this attribute is not supported,
-then a presentation processor must ignore the attribute.</p>
-<p>The <att>tts:direction</att> style is illustrated by the following example.</p>
-<table id="style-attribute-direction-example-1" role="example">
-<caption>Example Fragment &ndash; Direction</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;region xml:id="r1"&gt;
-  &lt;style tts:extent="265px 84px"/&gt;
-  &lt;style tts:padding="5px"/&gt;
-  &lt;style tts:backgroundColor="black"/&gt;
-  &lt;style tts:color="white"/&gt;
-  &lt;style tts:displayAlign="after"/&gt;
-  &lt;style tts:textAlign="center"/&gt;
-&lt;/region&gt;
-...
-&lt;p region="r1"&gt;
-  Little birds are playing&lt;br/&gt;
-  Bagpipes on the shore,&lt;br/&gt;
-  &lt;span tts:unicodeBidi="bidiOverride" <phrase role="strong">tts:direction="rtl"</phrase>&gt;where the tourists snore.&lt;/span&gt;
-&lt;/p&gt;
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p/>
-<table id="style-attribute-direction-example-1-images" role="example-images">
-<caption>Example Rendition &ndash; Direction</caption>
-<tbody>
-<tr>
-<td>
-<graphic source="images/direction.png" alt="TTML direction style property"/>
-</td>
-</tr>
-</tbody>
-</table>
-  <!-- CSS compatibility - remove derivation note 
-  <note role="derivation">
-<p>The semantics of the style property
-represented by this attribute are based upon that defined by <bibref ref="xsl11"/>,
-&sect; 7.29.1.</p>
-</note>
--->
-</div3>
-<div3 id="style-attribute-display">
-<head>tts:display</head>
-<p>The <att>tts:display</att> attribute is used to specify a style property that
-defines whether an element is a candidate for layout and composition
-in a region.</p>
-<p>This attribute may be specified by any
-element type
-that permits use of attributes in the TT Style Namespace; however, this attribute applies
-as a style property only to those element types indicated in the following table.</p>
-<table id="style-property-details-display" role="common">
-<col width="25%"/>
-<tbody>
-<tr>
-<td><emph>Values:</emph></td>
-<td>
-<code>auto</code> |
-<code>none</code>
-</td>
-</tr>
-<tr>
-<td><emph>Initial:</emph></td>
-<td>
-<code>auto</code>
-</td>
-</tr>
-<tr>
-<td><emph>Applies to:</emph></td>
-<td>
-<loc href="#document-structure-vocabulary-body"><el>body</el></loc>,
-<loc href="#content-vocabulary-div"><el>div</el></loc>,
-<loc href="#content-vocabulary-p"><el>p</el></loc>,
-<loc href="#layout-vocabulary-region"><el>region</el></loc>,
-<loc href="#content-vocabulary-span"><el>span</el></loc>
-</td>
-</tr>
-<tr>
-<td><emph>Inherited:</emph></td>
-<td>no</td>
-</tr>
-<tr>
-<td><emph>Percentages:</emph></td>
-<td>N/A</td>
-</tr>
-<tr>
-<td><emph>Animatable:</emph></td>
-<td>discrete</td>
-</tr>
-</tbody>
-</table>
-<p>For the purpose of determining applicability of this style property,
-each character child of a <el>p</el> element is considered to be enclosed in an anonymous
-span.</p>
-<p>If the value of this attribute is <code>auto</code>,
-then the affected element is a candidate for region layout and
-presentation; however, if the value is <code>none</code>, then the
-affected element and its descendants must be considered ineligible for region
-layout and presentation.</p>
-<p>The <att>tts:display</att> style is illustrated by the following example.</p>
-<table id="style-attribute-display-example-1" role="example">
-<caption>Example Fragment &ndash; Display</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;region xml:id="r1"&gt;
-  &lt;style tts:extent="369px 119px"
-            tts:backgroundColor="black"
-            tts:color="white"
-            tts:displayAlign="before"
-            tts:textAlign="start"/&gt;
-&lt;/region&gt;
-...
-&lt;div region="r1"&gt;
-  &lt;p dur="5s"&gt;
-    [[[
-    &lt;span <phrase role="strong">tts:display="none"</phrase>&gt;
-      &lt;set begin="1s" dur="1s" <phrase role="strong">tts:display="auto"</phrase>/&gt;
-      Beautiful soup,
-    &lt;/span&gt;
-    &lt;span <phrase role="strong">tts:display="none"</phrase>&gt;
-      &lt;set begin="2s" dur="1s" <phrase role="strong">tts:display="auto"</phrase>/&gt;
-      so rich and green,
-    &lt;/span&gt;
-    &lt;span <phrase role="strong">tts:display="none"</phrase>&gt;
-      &lt;set begin="3s" dur="1s" <phrase role="strong">tts:display="auto"</phrase>/&gt;
-      waiting in a hot tureen!
-    &lt;/span&gt;
-    ]]]
-  &lt;/p&gt;
-&lt;/div&gt;
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p/>
-<table id="style-attribute-display-example-1-images" role="example-images">
-<caption>Example Rendition &ndash; Display</caption>
-<tbody>
-<tr>
-<td>
-<graphic source="images/display_0.png" alt="TTML display style property - [0,1)"/>
-</td>
-</tr>
-<tr>
-<td>
-<graphic source="images/display_1.png" alt="TTML display style property - [1,2)"/>
-</td>
-</tr>
-<tr>
-<td>
-<graphic source="images/display_2.png" alt="TTML display style property - [2,3)"/>
-</td>
-</tr>
-<tr>
-<td>
-<graphic source="images/display_3.png" alt="TTML display style property - [3,4)"/>
-</td>
-</tr>
-<tr>
-<td>
-<graphic source="images/display_4.png" alt="TTML display style property - [4,5)"/>
-</td>
-</tr>
-</tbody>
-</table>
-  <!-- CSS compatibility - remove derivation note 
-  <note role="derivation">
-<p>The semantics of the style property
-represented by this attribute are based upon that defined by <bibref
-ref="css2"/>,
-&sect; 9.2.5.</p>
-</note>
--->
-</div3>
-<div3 id="style-attribute-displayAlign">
-<head>tts:displayAlign</head>
-<p>The <att>tts:displayAlign</att> attribute is used to specify a style property that
-defines the alignment of block areas in the block progression direction.</p>
-<p>This attribute may be specified by any
-element type
-that permits use of attributes in the TT Style Namespace; however, this attribute applies
-as a style property only to those element types indicated in the following table.</p>
-<table id="style-property-details-displayAlign" role="common">
-<col width="25%"/>
-<tbody>
-<tr>
-<td><emph>Values:</emph></td>
-<td>
-<code>before</code> |
-<code>center</code> |
-<code>after</code>
-</td>
-</tr>
-<tr>
-<td><emph>Initial:</emph></td>
-<td>
-<code>before</code>
-</td>
-</tr>
-<tr>
-<td><emph>Applies to:</emph></td>
-<td>
-<loc href="#layout-vocabulary-region"><el>region</el></loc>
-</td>
-</tr>
-<tr>
-<td><emph>Inherited:</emph></td>
-<td>no</td>
-</tr>
-<tr>
-<td><emph>Percentages:</emph></td>
-<td>N/A</td>
-</tr>
-<tr>
-<td><emph>Animatable:</emph></td>
-<td>discrete</td>
-</tr>
-</tbody>
-</table>
-<p>If a specified value of this attribute is not supported,
-then a presentation processor must interpret the attribute as if the
-value <code>before</code> were specified.</p>
-<p>The <att>tts:displayAlign</att> style is illustrated by the following example.</p>
-<table id="style-attribute-displayAlign-example-1" role="example">
-<caption>Example Fragment &ndash; Display Align</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;region xml:id="r1"&gt;
-  &lt;style tts:extent="128px 66px" tts:origin="0px 0px"
-       tts:backgroundColor="black" tts:color="white"/&gt;
-  &lt;style <phrase role="strong">tts:displayAlign="before"</phrase>/&gt;
-  &lt;style tts:textAlign="start"/&gt;
-&lt;/region&gt;
-&lt;region xml:id="r2"&gt;
-  &lt;style tts:extent="192px 66px" tts:origin="128px 66px"/&gt;
-       tts:backgroundColor="green" tts:color="white"/&gt;
-  &lt;style <phrase role="strong">tts:displayAlign="after"</phrase>/&gt;
-  &lt;style tts:textAlign="start"/&gt;
-&lt;/region&gt;
-&lt;region xml:id="r3"&gt;
-  &lt;style tts:extent="128px 66px"/&gt; style tts:origin="0px 132px"
-       tts:backgroundColor="black" tts:color="white"/&gt;
-  &lt;style <phrase role="strong">tts:displayAlign="before"</phrase>/&gt;
-  &lt;style tts:textAlign="start"/&gt;
-&lt;/region&gt;
-&lt;region xml:id="r4"&gt;
-  &lt;style tts:extent="192px 66px" tts:origin="128px 198px"/&gt;
-       tts:backgroundColor="green" tts:color="white"/&gt;
-  &lt;style <phrase role="strong">tts:displayAlign="after"</phrase>/&gt;
-  &lt;style tts:textAlign="start"/&gt;
-&lt;/region&gt;
-...
-&lt;div&gt;
-  &lt;p region="r1"&gt;I sent a message to the fish:&lt;/p&gt;
-  &lt;p region="r2"&gt;I told them&lt;br/&gt; "This is what I wish."&lt;/p&gt;
-  &lt;p region="r3"&gt;The little fishes of the sea,&lt;/p&gt;
-  &lt;p region="r4"&gt;They sent an&lt;br/&gt; answer back to me.&lt;/p&gt;
-&lt;/div&gt;
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p/>
-<table id="style-attribute-displayAlign-example-1-images" role="example-images">
-<caption>Example Rendition &ndash; Display Align</caption>
-<tbody>
-<tr>
-<td><graphic source="images/displayAlign.png" alt="TTML displayAlign style property"/></td>
-</tr>
-</tbody>
-</table>
-<!-- CSS compatibility - remove derivation note   
-<note role="derivation">
-<p>The semantics of the style property
-represented by this attribute are based upon that defined by <bibref ref="xsl11"/>,
-&sect; 7.14.4.</p>
-</note>
--->
-</div3>
-<div3 id="style-attribute-extent">
-<head>tts:extent</head>
-<p>The <att>tts:extent</att> attribute is used to specify the
-<emph>width</emph> and <emph>height</emph> of a region area
-(which may be the root container region).</p>
-<p>This attribute may be specified by any
-element type
-that permits use of attributes in the TT Style Namespace; however, this attribute applies
-as a style property only to those element types indicated in the following table.</p>
-<table id="style-property-details-extent" role="common">
-<col width="25%"/>
-<tbody>
-<tr>
-<td><emph>Values:</emph></td>
-<td>
-<code>auto</code> |
-<loc href="#style-value-length">&lt;length&gt;</loc> <loc href="#style-value-length">&lt;length&gt;</loc>
-</td>
-</tr>
-<tr>
-<td><emph>Initial:</emph></td>
-<td><code>auto</code></td>
-</tr>
-<tr>
-<td><emph>Applies to:</emph></td>
-<td>
-<loc href="#document-structure-vocabulary-tt"><el>tt</el></loc>,
-<loc href="#layout-vocabulary-region"><el>region</el></loc>
-</td>
-</tr>
-<tr>
-<td><emph>Inherited:</emph></td>
-<td>no</td>
-</tr>
-<tr>
-<td><emph>Percentages:</emph></td>
-<td>relative to width and height of root container region</td>
-</tr>
-<tr>
-<td><emph>Animatable:</emph></td>
-<td>discrete</td>
-</tr>
-</tbody>
-</table>
-<p>If the value of this attribute consists of two <loc href="#style-value-length">&lt;length&gt;</loc>
-specifications, then they must be interpreted as <emph>width</emph>
-and <emph>height</emph>, where the first specification is the
-<emph>width</emph>, and the second specification is the
-<emph>height</emph>.</p>
-<p>If the value of this attribute is <code>auto</code>, then the initial value
-of the style property must be considered to be the same as the root container extent.
-</p>
-<p>
-The root container extent is determined either by a
-<att>tts:extent</att> specified on the <el>tt</el> element, if
-present, or by the external authoring context, if not present.
-If
-<att>tts:extent</att> is specified on the <el>tt</el> element,
-then
-the width and height
-must be
-expressed in terms of two
-<loc href="#style-value-length">&lt;length&gt;</loc> specifications,
-and
-these specifications must be expressed as non-percentage,
-definite lengths using pixel units.</p>
-<p>If a specified value of this attribute is not supported,
-then a presentation processor must interpret the attribute as if the
-value <code>auto</code> were specified.</p>
-<p>The <att>tts:extent</att> style is illustrated by the following example.</p>
-<table id="style-attribute-extent-example-1" role="example">
-<caption>Example Fragment &ndash; Extent</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;region xml:id="r1"&gt;
-  &lt;style <phrase role="strong">tts:extent="330px 122px"</phrase>/&gt;
-  &lt;style tts:backgroundColor="black"/&gt;
-  &lt;style tts:color="white"/&gt;
-  &lt;style tts:displayAlign="after"/&gt;
-  &lt;style tts:textAlign="center"/&gt;
-&lt;/region&gt;
-...
-&lt;p region="r1"&gt;
-  'Tis the voice of the Lobster:&lt;br/&gt;
-  I heard him declare,&lt;br/&gt;
-  "You have baked me too brown,&lt;br/&gt;
-  I must sugar my hair."
-&lt;/p&gt;
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p/>
-<table id="style-attribute-extent-example-1-images" role="example-images">
-<caption>Example Rendition &ndash; Extent</caption>
-<tbody>
-<tr>
-<td><graphic source="images/extent.png" alt="TTML extent style property"/></td>
-</tr>
-</tbody>
-</table>
-</div3>
-<div3 id="style-attribute-fontFamily">
-<head>tts:fontFamily</head>
-<p>The <att>tts:fontFamily</att> attribute is used to specify a style property that
-defines the font family from which glyphs are selected for glyph areas generated
-by content flowed into a region.</p>
-<p>This attribute may be specified by any
-element type
-that permits use of attributes in the TT Style Namespace; however, this attribute applies
-as a style property only to those element types indicated in the following table.</p>
-<table id="style-property-details-fontFamily" role="common">
-<col width="25%"/>
-<tbody>
-<tr>
-<td><emph>Values:</emph></td>
-<td>
-(<loc href="#style-value-familyName">&lt;familyName&gt;</loc> | <loc href="#style-value-genericFamilyName">&lt;genericFamilyName&gt;</loc>)
-(<code>","</code>
-&nbsp;(<loc href="#style-value-familyName">&lt;familyName&gt;</loc> | <loc href="#style-value-genericFamilyName">&lt;genericFamilyName&gt;</loc>))*
-</td>
-</tr>
-<tr>
-<td><emph>Initial:</emph></td>
-<td><code>default</code></td>
-</tr>
-<tr>
-<td><emph>Applies to:</emph></td>
-<td>
-<loc href="#content-vocabulary-span"><el>span</el></loc>
-</td>
-</tr>
-<tr>
-<td><emph>Inherited:</emph></td>
-<td>yes</td>
-</tr>
-<tr>
-<td><emph>Percentages:</emph></td>
-<td>N/A</td>
-</tr>
-<tr>
-<td><emph>Animatable:</emph></td>
-<td>discrete</td>
-</tr>
-</tbody>
-</table>
-<note role="clarification">
-<p>The initial value, <code>default</code>, is a generic font family name, and is
-further described in <specref ref="style-value-genericFamilyName"/> below.</p>
-</note>
-<p>For the purpose of determining applicability of this style property,
-each character child of a <el>p</el> element is considered to be enclosed in an anonymous
-span.</p>
-<p>If a specified font family is not available, then a
-presentation processor must attempt to map the specified font family
-to an available font family that has similar typographic
-characteristics, or, in the absence of such a mapping, it must
-interpret the font family as if the value <code>default</code> were
-specified.</p>
-<p>The <att>tts:fontFamily</att> style is illustrated by the following example.</p>
-<table id="style-attribute-fontFamily-example-1" role="example">
-<caption>Example Fragment &ndash; Font Family</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;region xml:id="r1"&gt;
-  &lt;style tts:extent="474px 146px"/&gt;
-  &lt;style tts:backgroundColor="black"/&gt;
-  &lt;style tts:color="white"/&gt;
-  &lt;style tts:displayAlign="center"/&gt;
-  &lt;style tts:textAlign="start"/&gt;
-  &lt;style <phrase role="strong">tts:fontFamily="proportionalSansSerif"</phrase>/&gt;
-&lt;/region&gt;
-...
-&lt;div region="r1"&gt;
-  &lt;p&gt;
-    "The time has come," the Walrus said,&lt;br/&gt;
-    "to talk of many things:
-  &lt;/p&gt;
-  &lt;p tts:textAlign="end" <phrase role="strong">tts:fontFamily="monospaceSerif"</phrase>&gt;
-    Of shoes, and ships, and sealing wax,&lt;br/&gt;
-    Of cabbages and kings,
-  &lt;/p&gt;
-  &lt;p&gt;
-    And why the sea is boiling hot,&lt;br/&gt;
-    and whether pigs have wings."
-  &lt;/p&gt;
-&lt;/div&gt;
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p/>
-<table id="style-attribute-fontFamily-example-1-images" role="example-images">
-<caption>Example Rendition &ndash; Font Family</caption>
-<tbody>
-<tr>
-<td><graphic source="images/fontFamily.png" alt="TTML fontFamily style property"/></td>
-</tr>
-</tbody>
-</table>
-<!--CSS compatibility - remove derivation note
-<note role="derivation">
-<p>The semantics of the style property
-represented by this attribute are based upon that defined by <bibref ref="xsl11"/>,
-&sect; 7.9.2.</p>
-</note>
--->
-</div3>
-<div3 id="style-attribute-fontSize">
-<head>tts:fontSize</head>
-<p>The <att>tts:fontSize</att> attribute is used to specify a style property
-that defines the font size for glyphs that are selected for glyph areas
-generated by content flowed into a region, where font size is interpreted as a
-scaling transform to the font's design EM square.</p>
-<p>This attribute may be specified by any
-element type
-that permits use of attributes in the TT Style Namespace; however, this attribute applies
-as a style property only to those element types indicated in the following table.</p>
-<table id="style-property-details-fontSize" role="common">
-<col width="25%"/>
-<tbody>
-<tr>
-<td><emph>Values:</emph></td>
-<td>
-<loc href="#style-value-length">&lt;length&gt;</loc> <loc href="#style-value-length">&lt;length&gt;</loc>?
-</td>
-</tr>
-<tr>
-<td><emph>Initial:</emph></td>
-<td><code>1c</code></td>
-</tr>
-<tr>
-<td><emph>Applies to:</emph></td>
-<td>
-<loc href="#content-vocabulary-span"><el>span</el></loc>
-</td>
-</tr>
-<tr>
-<td><emph>Inherited:</emph></td>
-<td>yes</td>
-</tr>
-<tr>
-<td><emph>Percentages:</emph></td>
-<td>relative to parent element's font size</td>
-</tr>
-<tr>
-<td><emph>Animatable:</emph></td>
-<td>discrete</td>
-</tr>
-</tbody>
-</table>
-<p>If a single <loc href="#style-value-length">&lt;length&gt;</loc> value is specified, then this length applies
-equally to horizontal and vertical scaling of a glyph's EM square; if two
-<loc href="#style-value-length">&lt;length&gt;</loc> values are specified, then the first expresses the horizontal
-scaling and the second expresses vertical scaling.</p>
-<note role="example">
-<p>Use of independent horizontal and vertical font sizes is expected to be used
-with cell based units in order to denote fonts that are two rows in height and
-one column in width.</p>
-</note>
-<p>If horizontal and vertical sizes are expressed independently, then the
-units of the <loc href="#style-value-length">&lt;length&gt;</loc> values must be the same.</p>
-<p>The <loc href="#style-value-length">&lt;length&gt;</loc> value(s) used to express font size must be non-negative.</p>
-<p>For the purpose of determining applicability of this style property,
-each character child of a <el>p</el> element is considered to be enclosed in an anonymous
-span.</p>
-<p>If a specified value of this attribute is not supported,
-then a presentation processor must interpret the attribute as if the
-value <code>1c</code> were specified.</p>
-<note role="elaboration">
-<p>The expression <code>1c</code> means one cell, where <code>'c'</code> expresses
-the <emph>cell</emph> length unit as defined by <specref ref="style-value-length"/>.</p>
-</note>
-<p>The <att>tts:fontSize</att> style is illustrated by the following example.</p>
-<table id="style-attribute-fontSize-example-1" role="example">
-<caption>Example Fragment &ndash; Font Size</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;region xml:id="r1"&gt;
-  &lt;style tts:extent="299px 97px"/&gt;
-  &lt;style tts:backgroundColor="black"/&gt;
-  &lt;style tts:color="white"/&gt;
-  &lt;style tts:displayAlign="center"/&gt;
-  &lt;style tts:textAlign="center"/&gt;
-  &lt;style tts:fontFamily="proportionalSansSerif"/&gt;
-  &lt;style <phrase role="strong">tts:fontSize="18px"</phrase>/&gt;
-&lt;/region&gt;
-...
-&lt;p region="r1"&gt;
-  Then fill up the glasses&lt;br/&gt;
-  with treacle and ink,&lt;br/&gt;
-  Or anything else&lt;br/&gt;
-  that is &lt;span <phrase role="strong">tts:fontSize="24px"</phrase>&gt;pleasant&lt;/span&gt; to drink.
-&lt;/p&gt;
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p/>
-<table id="style-attribute-fontSize-example-1-images" role="example-images">
-<caption>Example Rendition &ndash; Font Size</caption>
-<tbody>
-<tr>
-<td><graphic source="images/fontSize.png" alt="TTML fontSize style property"/></td>
-</tr>
-</tbody>
-</table>
-<!--CSS compatibility - remove derivation note
-<note role="derivation">
-<p>The semantics of the style property
-represented by this attribute are based upon that defined by <bibref ref="xsl11"/>,
-&sect; 7.9.4.</p>
-</note>
--->  
-</div3>
-<div3 id="style-attribute-fontStyle">
-<head>tts:fontStyle</head>
-<p>The <att>tts:fontStyle</att> attribute is used to specify a style property that
-defines the font style to apply to glyphs that are selected for glyph areas generated
-by content flowed into a region, where the mapping from font
-style value to specific font face or style parameterization is not determined
-by this specification.</p>
-<p>This attribute may be specified by any
-element type
-that permits use of attributes in the TT Style Namespace; however, this attribute applies
-as a style property only to those element types indicated in the following table.</p>
-<table id="style-property-details-fontStyle" role="common">
-<col width="25%"/>
-<tbody>
-<tr>
-<td><emph>Values:</emph></td>
-<td>
-<code>normal</code> |
-<code>italic</code> |
-<code>oblique</code>
-</td>
-</tr>
-<tr>
-<td><emph>Initial:</emph></td>
-<td><code>normal</code></td>
-</tr>
-<tr>
-<td><emph>Applies to:</emph></td>
-<td>
-<loc href="#content-vocabulary-span"><el>span</el></loc>
-</td>
-</tr>
-<tr>
-<td><emph>Inherited:</emph></td>
-<td>yes</td>
-</tr>
-<tr>
-<td><emph>Percentages:</emph></td>
-<td>N/A</td>
-</tr>
-<tr>
-<td><emph>Animatable:</emph></td>
-<td>discrete</td>
-</tr>
-</tbody>
-</table>
-<p>For the purpose of determining applicability of this style property,
-each character child of a <el>p</el> element is considered to be enclosed in an anonymous
-span.</p>
-<p>Use of the value <code>oblique</code>
-denote a shear transformation (at an unspecified
-angle) in the inline progression dimension.</p>
-<p>If a specified font style is not available, then a
-presentation processor must attempt to map the specified font style
-to an available font style that has similar typographic
-characteristics, or, in the absence of such a mapping, it must
-interpret the font style as if the value <code>normal</code> were
-specified.</p>
-<p>The <att>tts:fontStyle</att> style is illustrated by the following example.</p>
-<table id="style-attribute-fontStyle-example-1" role="example">
-<caption>Example Fragment &ndash; Font Style</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;region xml:id="r1"&gt;
-  &lt;style tts:extent="331px 84px"/&gt;
-  &lt;style tts:backgroundColor="black"/&gt;
-  &lt;style tts:color="white"/&gt;
-  &lt;style tts:displayAlign="after"/&gt;
-  &lt;style tts:textAlign="center"/&gt;
-  &lt;style tts:fontFamily="proportionalSansSerif"/&gt;
-&lt;/region&gt;
-...
-&lt;p region="r1"&gt;
-  In autumn, when the leaves are brown,&lt;br/&gt;
-  Take pen and ink, and &lt;span <phrase role="strong">tts:fontStyle="italic"</phrase>&gt;write it down.&lt;/span&gt;
-&lt;/p&gt;
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p/>
-<table id="style-attribute-fontStyle-example-1-images" role="example-images">
-<caption>Example Rendition &ndash; Font Style</caption>
-<tbody>
-<tr>
-<td><graphic source="images/fontStyle.png" alt="TTML fontStyle style property"/></td>
-</tr>
-</tbody>
-</table>
-<p/>
-<!-- CSS compatibility - remove derivation note
-<note role="derivation">
-<p>The semantics of the style property
-represented by this attribute are based upon that defined by <bibref ref="xsl11"/>,
-&sect; 7.9.7.</p>
-</note>
--->  
-</div3>
-<div3 id="style-attribute-fontWeight">
-<head>tts:fontWeight</head>
-<p>The <att>tts:fontWeight</att> attribute is used to specify a style property
-that defines the font weight to apply to glyphs that are selected for glyph
-areas generated by content flowed into a region, where the mapping from font
-weight value to specific font face or weight parameterization is not determined
-by this specification.</p>
-<p>This attribute may be specified by any
-element type
-that permits use of attributes in the TT Style Namespace; however, this attribute applies
-as a style property only to those element types indicated in the following table.</p>
-<table id="style-property-details-fontWeight" role="common">
-<col width="25%"/>
-<tbody>
-<tr>
-<td><emph>Values:</emph></td>
-<td>
-<code>normal</code> |
-<code>bold</code>
-</td>
-</tr>
-<tr>
-<td><emph>Initial:</emph></td>
-<td><code>normal</code></td>
-</tr>
-<tr>
-<td><emph>Applies to:</emph></td>
-<td>
-<loc href="#content-vocabulary-span"><el>span</el></loc>
-</td>
-</tr>
-<tr>
-<td><emph>Inherited:</emph></td>
-<td>yes</td>
-</tr>
-<tr>
-<td><emph>Percentages:</emph></td>
-<td>N/A</td>
-</tr>
-<tr>
-<td><emph>Animatable:</emph></td>
-<td>discrete</td>
-</tr>
-</tbody>
-</table>
-<p>For the purpose of determining applicability of this style property,
-each character child of a <el>p</el> element is considered to be enclosed in an anonymous
-span.</p>
-<p>If a specified font weight is not available, then a
-presentation processor must attempt to map the specified font weight
-to an available font weight that has similar typographic
-characteristics, or, in the absence of such a mapping, it must
-interpret the font weight as if the value <code>normal</code> were
-specified.</p>
-<p>The <att>tts:fontWeight</att> style is illustrated by the following example.</p>
-<table id="style-attribute-fontWeight-example-1" role="example">
-<caption>Example Fragment &ndash; Font Weight</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;region xml:id="r1"&gt;
-  &lt;style tts:extent="376px 95px"/&gt;
-  &lt;style tts:backgroundColor="black"/&gt;
-  &lt;style tts:color="white"/&gt;
-  &lt;style tts:displayAlign="center"/&gt;
-  &lt;style tts:textAlign="center"/&gt;
-  &lt;style tts:fontFamily="proportionalSansSerif"/&gt;
-&lt;/region&gt;
-...
-&lt;p region="r1"&gt;
-  They told me you had been to her,&lt;br/&gt;
-  &lt;span <phrase role="strong">tts:fontWeight="bold"</phrase>&gt;and mentioned me to him:&lt;/span&gt;&lt;br/&gt;
-  She gave me a good character&lt;br/&gt;
-  &lt;span <phrase role="strong">tts:fontWeight="bold"</phrase>&gt;but said I could not swim.&lt;/span&gt;
-&lt;/p&gt;
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p/>
-<table id="style-attribute-fontWeight-example-1-images" role="example-images">
-<caption>Example Rendition &ndash; Font Weight</caption>
-<tbody>
-<tr>
-<td><graphic source="images/fontWeight.png" alt="TTML fontWeight style property"/></td>
-</tr>
-</tbody>
-</table>
-<!--CSS compatibility - remove derivation note
-<note role="derivation">
-<p>The semantics of the style property
-represented by this attribute are based upon that defined by <bibref ref="xsl11"/>,
-&sect; 7.9.9.</p>
-</note>
--->
-</div3>
-<div3 id="style-attribute-lineHeight">
-<head>tts:lineHeight</head>
-<p>The <att>tts:lineHeight</att> attribute is used to specify a style property that
-defines the inter-baseline separation between line areas generated by content flowed into a region.</p>
-<p>This attribute may be specified by any
-element type
-that permits use of attributes in the TT Style Namespace; however, this attribute applies
-as a style property only to those element types indicated in the following table.</p>
-<table id="style-property-details-lineHeight" role="common">
-<col width="25%"/>
-<tbody>
-<tr>
-<td><emph>Values:</emph></td>
-<td>
-<code>normal</code> |
-<loc href="#style-value-length">&lt;length&gt;</loc>
-</td>
-</tr>
-<tr>
-<td><emph>Initial:</emph></td>
-<td><code>normal</code></td>
-</tr>
-<tr>
-<td><emph>Applies to:</emph></td>
-<td>
-<loc href="#content-vocabulary-p"><el>p</el></loc>
-</td>
-</tr>
-<tr>
-<td><emph>Inherited:</emph></td>
-<td>yes</td>
-</tr>
-<tr>
-<td><emph>Percentages:</emph></td>
-<td>relative to this element's font size</td>
-</tr>
-<tr>
-<td><emph>Animatable:</emph></td>
-<td>discrete</td>
-</tr>
-</tbody>
-</table>
-<p>If the value of this attribute is <code>normal</code>, then the
-initial value of the style property must be considered to be the same
-as the largest font size that applies to any
-descendant element.</p>
-<p>If specified as a <loc
-href="#style-value-length">&lt;length&gt;</loc>, then the length must
-be non-negative.</p>
-<p>If a specified value of this attribute is not supported,
-then a presentation processor must interpret the attribute as if the
-value <code>normal</code> were specified.</p>
-<p>The <att>tts:lineHeight</att> style is illustrated by the following example.</p>
-<table id="style-attribute-lineHeight-example-1" role="example">
-<caption>Example Fragment &ndash; Line Height</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;region xml:id="r1"&gt;
-  &lt;style tts:extent="255px 190px"/&gt;
-  &lt;style tts:backgroundColor="black"/&gt;
-  &lt;style tts:color="white"/&gt;
-  &lt;style tts:displayAlign="center"/&gt;
-  &lt;style tts:textAlign="start"/&gt;
-  &lt;style tts:fontFamily="proportionalSansSerif"/&gt;
-  &lt;style tts:fontSize="16px"/&gt;
-  &lt;style <phrase role="strong">tts:lineHeight="32px"</phrase>/&gt;
-&lt;/region&gt;
-...
-&lt;p region="r1"&gt;
-  He thought he saw an elephant,&lt;br/&gt;
-  That practised on a fife:&lt;br/&gt;
-  He looked again, and found it was&lt;br/&gt;
-  A letter from his wife.&lt;br/&gt;
-  "At length I realise," he said,&lt;br/&gt;
-  "The bitterness of Life.
-"&lt;/p&gt;
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p/>
-<table id="style-attribute-lineHeight-example-1-images" role="example-images">
-<caption>Example Rendition &ndash; Line Height</caption>
-<tbody>
-<tr>
-<td><graphic source="images/lineHeight.png" alt="TTML lineHeight style property"/></td>
-</tr>
-</tbody>
-</table>
-<p/>
-<!-- CSS compatibility - remove derivation note
-<note role="derivation">
-<p>The semantics of the style property
-represented by this attribute are based upon that defined by <bibref ref="xsl11"/>,
-&sect; 7.16.4.</p>
-</note>
--->
-</div3>
-<div3 id="style-attribute-opacity">
-<head>tts:opacity</head>
-<p>The <att>tts:opacity</att> attribute is used to specify a style property that
-defines the opacity (or conversely, the transparency)
-of marks associated with a region.</p>
-<p>When presented onto a visual medium, the opacity of the region is applied uniformly and on a linear scale
-to all marks produced by content targeted to the
-region.</p>
-<p>This attribute may be specified by any
-element type
-that permits use of attributes in the TT Style Namespace; however, this attribute applies
-as a style property only to those element types indicated in the following table.</p>
-<table id="style-property-details-opacity" role="common">
-<col width="25%"/>
-<tbody>
-<tr>
-<td><emph>Values:</emph></td>
-<td>
-<loc href="#style-value-alpha">&lt;alpha&gt;</loc>
-</td>
-</tr>
-<tr>
-<td><emph>Initial:</emph></td>
-<td>
-<code>1.0</code>
-</td>
-</tr>
-<tr>
-<td><emph>Applies to:</emph></td>
-<td>
-<loc href="#layout-vocabulary-region"><el>region</el></loc>
-</td>
-</tr>
-<tr>
-<td><emph>Inherited:</emph></td>
-<td>no</td>
-</tr>
-<tr>
-<td><emph>Percentages:</emph></td>
-<td>N/A</td>
-</tr>
-<tr>
-<td><emph>Animatable:</emph></td>
-<td>discrete</td>
-</tr>
-</tbody>
-</table>
-<p>An <loc href="#style-value-alpha">&lt;alpha&gt;</loc> value greater
-than 1.0 must be considered equivalent to an <loc
-href="#style-value-alpha">&lt;alpha&gt;</loc> value of 1.0.</p>
-<p>The <att>tts:opacity</att> style is illustrated by the following example.</p>
-<table id="style-attribute-opacity-example-1" role="example">
-<caption>Example Fragment &ndash; Opacity</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;region xml:id="r1" dur="5s"&gt;
-  &lt;set begin="0s" dur="1s" <phrase role="strong">tts:opacity="1.00"</phrase>/&gt;
-  &lt;set begin="1s" dur="1s" <phrase role="strong">tts:opacity="0.75"</phrase>/&gt;
-  &lt;set begin="2s" dur="1s" <phrase role="strong">tts:opacity="0.50"</phrase>/&gt;
-  &lt;set begin="3s" dur="1s" <phrase role="strong">tts:opacity="0.25"</phrase>/&gt;
-  &lt;set begin="4s" dur="1s" <phrase role="strong">tts:opacity="0.00"</phrase>/&gt;
-  &lt;style tts:extent="304px 77px"/&gt;
-  &lt;style tts:backgroundColor="black"/&gt;
-  &lt;style tts:color="white"/&gt;
-  &lt;style tts:displayAlign="after"/&gt;
-  &lt;style tts:textAlign="center"/&gt;
-&lt;/region&gt;
-...
-&lt;p region="r1"&gt;
-  The sun was shining on the sea
-&lt;/p&gt;
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p/>
-<table id="style-attribute-opacity-example-1-images" role="example-images">
-<caption>Example Rendition &ndash; Opacity</caption>
-<tbody>
-<tr>
-<td>
-<graphic source="images/opacity_0.png" alt="TTML opacity style property - [0,1)"/>
-</td>
-</tr>
-<tr>
-<td>
-<graphic source="images/opacity_1.png" alt="TTML opacity style property - [1,2)"/>
-</td>
-</tr>
-<tr>
-<td>
-<graphic source="images/opacity_2.png" alt="TTML opacity style property - [2,3)"/>
-</td>
-</tr>
-<tr>
-<td>
-<graphic source="images/opacity_3.png" alt="TTML opacity style property - [3,4)"/>
-</td>
-</tr>
-<tr>
-<td>
-<graphic source="images/opacity_4.png" alt="TTML opacity style property - [4,5)"/>
-</td>
-</tr>
-</tbody>
-</table>
-<!--CSS compatibility - remove derivation note
-<note role="derivation">
-<p>The semantics of the style property
-represented by this attribute are based upon that defined by <bibref ref="css3-color"/>,
-&sect; 3.2.</p>
-</note>
--->
-</div3>
-<div3 id="style-attribute-origin">
-<head>tts:origin</head>
-<p>The <att>tts:origin</att> attribute is used to specify the
-<emph>x</emph> and <emph>y</emph> coordinates of the origin of a
-region area with respect to the origin of the root container extent,
-if specified, or the external authoring context, if not specified.</p>
-<p>This attribute may be specified by any
-element type
-that permits use of attributes in the TT Style Namespace; however, this attribute applies
-as a style property only to those element types indicated in the following table.</p>
-<table id="style-property-details-origin" role="common">
-<col width="25%"/>
-<tbody>
-<tr>
-<td><emph>Values:</emph></td>
-<td>
-<code>auto</code> |
-<loc href="#style-value-length">&lt;length&gt;</loc> <loc href="#style-value-length">&lt;length&gt;</loc>
-</td>
-</tr>
-<tr>
-<td><emph>Initial:</emph></td>
-<td><code>auto</code></td>
-</tr>
-<tr>
-<td><emph>Applies to:</emph></td>
-<td>
-<loc href="#layout-vocabulary-region"><el>region</el></loc>
-</td>
-</tr>
-<tr>
-<td><emph>Inherited:</emph></td>
-<td>no</td>
-</tr>
-<tr>
-<td><emph>Percentages:</emph></td>
-<td>relative to width and height of root container region</td>
-</tr>
-<tr>
-<td><emph>Animatable:</emph></td>
-<td>discrete</td>
-</tr>
-</tbody>
-</table>
-<p>If the value of this attribute consists of two <loc href="#style-value-length">&lt;length&gt;</loc> specifications,
-then they must be interpreted as <emph>x</emph> and <emph>y</emph> coordinates, where the first specification
-is the <emph>x</emph> coordinate, and the second specification is the <emph>y</emph> coordinate.</p>
-<p>If the value of this attribute is <code>auto</code>, then the initial value
-of the style property must be considered to be the same as the root container
-origin.</p>
-<p>If a specified value of this attribute is not supported,
-then a presentation processor must interpret the attribute as if the
-value <code>auto</code> were specified.</p>
-<p>The <att>tts:origin</att> style is illustrated by the following example.</p>
-<table id="style-attribute-origin-example-1" role="example">
-<caption>Example Fragment &ndash; Origin</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;region xml:id="r1"&gt;
-  &lt;style <phrase role="strong">tts:origin="40px 40px"</phrase>/&gt;
-  &lt;style tts:extent="308px 92px"/&gt;
-  &lt;style tts:backgroundColor="black"/&gt;
-  &lt;style tts:color="white"/&gt;
-  &lt;style tts:displayAlign="center"/&gt;
-  &lt;style tts:textAlign="center"/&gt;
-&lt;/region&gt;
-...
-&lt;p region="r1"&gt;
-  "To dine!" she shrieked in dragon-wrath.&lt;br/&gt;
-  "To swallow wines all foam and froth!&lt;br/&gt;
-   To simper at a table-cloth!"
-&lt;/p&gt;
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p/>
-<table id="style-attribute-origin-example-1-images" role="example-images">
-<caption>Example Rendition &ndash; Origin</caption>
-<tbody>
-<tr>
-<td><graphic source="images/origin.png" alt="TTML origin style property"/></td>
-</tr>
-</tbody>
-</table>
-</div3>
-<div3 id="style-attribute-overflow">
-<head>tts:overflow</head>
-<p>The <att>tts:overflow</att> attribute is used to specify a style property that
-defines whether a region area is clipped or not if the descendant areas of the region overflow
-its extent.</p>
-<p>This attribute may be specified by any
-element type
-that permits use of attributes in the TT Style Namespace; however, this attribute applies
-as a style property only to those element types indicated in the following table.</p>
-<table id="style-property-details-overflow" role="common">
-<col width="25%"/>
-<tbody>
-<tr>
-<td><emph>Values:</emph></td>
-<td>
-<code>visible</code> |
-<code>hidden</code>
-</td>
-</tr>
-<tr>
-<td><emph>Initial:</emph></td>
-<td><code>hidden</code></td>
-</tr>
-<tr>
-<td><emph>Applies to:</emph></td>
-<td>
-<loc href="#layout-vocabulary-region"><el>region</el></loc>
-</td>
-</tr>
-<tr>
-<td><emph>Inherited:</emph></td>
-<td>no</td>
-</tr>
-<tr>
-<td><emph>Percentages:</emph></td>
-<td>N/A</td>
-</tr>
-<tr>
-<td><emph>Animatable:</emph></td>
-<td>discrete</td>
-</tr>
-</tbody>
-</table>
-<p>If the value of this attribute is <code>visible</code>, then content should
-not be clipped outside of the affected region, and region composition and layout
-must be performed as if the region's width and height were
-unconstrained,
-but with
-a well-defined origin.  If the value is <code>hidden</code>, then content should
-be clipped outside of the affected region.</p>
-<note role="explanation">
-<p>Unless a manual line break element <el>br</el> is used by the content author,
-a paragraph of a given region will generate no more than one line area in that
-region if the value of the <att>tts:overflow</att> style that applies to the
-region is <code>visible</code> and if the applicable <att>tts:wrapOption</att>
-style is <code>noWrap</code>.</p>
-</note>
-<p>If a specified value of this attribute is not supported,
-then a presentation processor must interpret the attribute as if the
-value <code>hidden</code> were specified.</p>
-<p>The <att>tts:overflow</att> style is illustrated by the following example.</p>
-<table id="style-attribute-overflow-example-1" role="example">
-<caption>Example Fragment &ndash; Overflow</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;region xml:id="r1"&gt;
-  &lt;style tts:extent="232px 40px"/&gt;
-  &lt;style tts:origin="0px 0px"/&gt;
-  &lt;style tts:backgroundColor="black"/&gt;
-  &lt;style tts:color="red"/&gt;
-  &lt;style tts:displayAlign="before"/&gt;
-  &lt;style tts:textAlign="start"/&gt;
-  &lt;style tts:fontFamily="proportionalSansSerif"/&gt;
-  &lt;style tts:fontSize="18px"/&gt;
-  &lt;style tts:wrapOption="noWrap"/&gt;
-  &lt;style <phrase role="strong">tts:overflow="visible"</phrase>/&gt;
-&lt;/region&gt;
-&lt;region xml:id="r2"&gt;
-  &lt;style tts:extent="232px 40px"/&gt;
-  &lt;style tts:origin="0px 43px"/&gt;
-  &lt;style tts:backgroundColor="black"/&gt;
-  &lt;style tts:color="red"/&gt;
-  &lt;style tts:displayAlign="before"/&gt;
-  &lt;style tts:textAlign="start"/&gt;
-  &lt;style tts:fontFamily="proportionalSansSerif"/&gt;
-  &lt;style tts:fontSize="18px"/&gt;
-  &lt;style tts:wrapOption="noWrap"/&gt;
-  &lt;style <phrase role="strong">tts:overflow="hidden"</phrase>/&gt;
-&lt;/region&gt;
-...
-&lt;p region="r1"&gt;
-  "But wait a bit," the Oysters cried,&lt;br/&gt;
-  "Before we have our chat;
-&lt;/p&gt;
-&lt;p region="r2"&gt;
-  For some of us are out of breath,&lt;br/&gt;
-  And all of us are fat!"
-&lt;/p&gt;
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p/>
-<table id="style-attribute-overflow-example-1-images" role="example-images">
-<caption>Example Rendition &ndash; Overflow</caption>
-<tbody>
-<tr>
-<td><graphic source="images/overflow.png" alt="TTML overflow style property"/></td>
-</tr>
-</tbody>
-</table>
-<note role="explanation">
-<p>In the above example, the <att>tts:noWrap</att> is set to
-<code>noWrap</code> to prevent automatic line wrapping (breaking);
-if this were not specified, then overflow would occur in the block
-progression direction as opposed to the inline progression direction.</p>
-</note>
-<!-- CSS compatibility - remove derivation note
-<note role="derivation">
-<p>The semantics of the style property
-represented by this attribute are based upon that defined by <bibref ref="xsl11"/>,
-&sect; 7.21.2.</p>
-</note>
--->  
-</div3>
-<div3 id="style-attribute-padding">
-<head>tts:padding</head>
-<p>The <att>tts:padding</att> attribute is used to specify padding (or inset)
-space on all sides of a region area.</p>
-<p>This attribute may be specified by any
-element type
-that permits use of attributes in the TT Style Namespace; however, this attribute applies
-as a style property only to those element types indicated in the following table.</p>
-<table id="style-property-details-padding" role="common">
-<col width="25%"/>
-<tbody>
-<tr>
-<td><emph>Values:</emph></td>
-<td>
-<loc href="#style-value-length">&lt;length&gt;</loc> |
-<loc href="#style-value-length">&lt;length&gt;</loc> <loc href="#style-value-length">&lt;length&gt;</loc> |
-<loc href="#style-value-length">&lt;length&gt;</loc> <loc href="#style-value-length">&lt;length&gt;</loc> <loc href="#style-value-length">&lt;length&gt;</loc> |
-<loc href="#style-value-length">&lt;length&gt;</loc> <loc href="#style-value-length">&lt;length&gt;</loc> <loc href="#style-value-length">&lt;length&gt;</loc> <loc href="#style-value-length">&lt;length&gt;</loc>
-</td>
-</tr>
-<tr>
-<td><emph>Initial:</emph></td>
-<td><code>0px</code></td>
-</tr>
-<tr>
-<td><emph>Applies to:</emph></td>
-<td>
-<loc href="#layout-vocabulary-region"><el>region</el></loc>
-</td>
-</tr>
-<tr>
-<td><emph>Inherited:</emph></td>
-<td>no</td>
-</tr>
-<tr>
-<td><emph>Percentages:</emph></td>
-<td>relative to width and height of region</td>
-</tr>
-<tr>
-<td><emph>Animatable:</emph></td>
-<td>discrete</td>
-</tr>
-</tbody>
-</table>
-<p>If the value of this attribute consists of one <loc href="#style-value-length">&lt;length&gt;</loc> specification,
-then that length applies to all edges of the affected areas. If the value
-consists of two <loc href="#style-value-length">&lt;length&gt;</loc> specifications, then the first applies to the
-before and after edges, and the second applies to the start and end edges.
-If three <loc href="#style-value-length">&lt;length&gt;</loc> specifications are provided, then the first applies to the
-before edge, the second applies to the start and end edges, and the third applies
-to the after edge.
-If four <loc href="#style-value-length">&lt;length&gt;</loc> specifications are provided, then they apply to before, end,
-after, and start edges, respectively.</p>
-<p>If a specified value of this attribute is not supported,
-then a presentation processor must interpret the attribute as if the
-value <code>0px</code> were specified.</p>
-<p>The <att>tts:padding</att> style is illustrated by the following example.</p>
-<table id="style-attribute-padding-example-1" role="example">
-<caption>Example Fragment &ndash; Padding</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;region xml:id="r1"&gt;
-  &lt;style tts:extent="446px 104px"/&gt;
-  &lt;style tts:backgroundColor="black"/&gt;
-  &lt;style tts:color="white"/&gt;
-  &lt;style tts:displayAlign="after"/&gt;
-  &lt;style tts:textAlign="center"/&gt;
-  &lt;style <phrase role="strong">tts:padding="10px 40px"</phrase>/&gt;
-&lt;/region&gt;
-...
-&lt;p region="r1" tts:backgroundColor="red"&gt;
-  Just the place for a Snark! I have said it twice:&lt;br/&gt;
-  That alone should encourage the crew.&lt;br/&gt;
-  Just the place for a Snark! I have said it thrice:&lt;br/&gt;
-  What I tell you three times is true.
-&lt;/p&gt;
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p>When rendering an area to which padding applies, the background color that
-applies to the area is rendered into the padded portion of the area.</p>
-<table id="style-attribute-padding-example-1-images" role="example-images">
-<caption>Example Rendition &ndash; Padding</caption>
-<tbody>
-<tr>
-<td>
-<graphic source="images/padding.png" alt="TTML padding style property"/>
-</td>
-</tr>
-</tbody>
-</table>
- <!-- CSS compatibility - remove derivation note
-<note role="derivation">
-<p>The semantics of the style property
-represented by this attribute are based upon that defined by <bibref ref="xsl11"/>,
-&sect; 7.31.15, except that individual shorthand values map to writing
-  mode relative padding values as defined by <bibref ref="xsl11"/>,
-&sect; 7.8.31, 7.8.32, 7.8.33, and 7.8.34.</p>
-</note>
--->
-</div3>
-<div3 id="style-attribute-showBackground">
-<head>tts:showBackground</head>
-<p>The <att>tts:showBackground</att> attribute is used to specify
-constraints on when the background color of a region is intended to be
-presented.</p>
-<p>This attribute may be specified by any
-element type
-that permits use of attributes in the TT Style Namespace; however, this attribute applies
-as a style property only to those element types indicated in the following table.</p>
-<table id="style-property-details-showBackground" role="common">
-<col width="25%"/>
-<tbody>
-<tr>
-<td><emph>Values:</emph></td>
-<td>
-<code>always</code> |
-<code>whenActive</code>
-</td>
-</tr>
-<tr>
-<td><emph>Initial:</emph></td>
-<td><code>always</code></td>
-</tr>
-<tr>
-<td><emph>Applies to:</emph></td>
-<td>
-<loc href="#layout-vocabulary-region"><el>region</el></loc>
-</td>
-</tr>
-<tr>
-<td><emph>Inherited:</emph></td>
-<td>no</td>
-</tr>
-<tr>
-<td><emph>Percentages:</emph></td>
-<td>N/A</td>
-</tr>
-<tr>
-<td><emph>Animatable:</emph></td>
-<td>discrete</td>
-</tr>
-</tbody>
-</table>
-<p>If the value of this attribute is <code>always</code>, then the
-background color of a region is always rendered when performing presentation
-processing on a visual medium; if the value is <code>whenActive</code>,
-then the background color of a region is rendered only when some
-content is selected into the region.</p>
-<p>If a specified value of this attribute is not supported,
-then a presentation processor must interpret the attribute as if the
-value <code>always</code> were specified.</p>
-<p>The <att>tts:showBackground</att> style is illustrated by the following example.</p>
-<table id="style-attribute-showBackground-example-1" role="example">
-<caption>Example Fragment &ndash; Show Background</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;region xml:id="r1"&gt;
-  &lt;style tts:origin="0px 0px"/&gt;
-  &lt;style tts:extent="265px 100px"/&gt;
-  &lt;style tts:backgroundColor="black"/&gt;
-  &lt;style <phrase role="strong">tts:showBackground="always"</phrase>/&gt;
-  &lt;style tts:color="white"/&gt;
-  &lt;style tts:displayAlign="before"/&gt;
-  &lt;style tts:textAlign="start"/&gt;
-&lt;/region&gt;
-&lt;region xml:id="r2"&gt;
-  &lt;style tts:origin="205px 60px"/&gt;
-  &lt;style tts:extent="290px 100px"/&gt;
-  &lt;style tts:backgroundColor="red"/&gt;
-  &lt;style tts:color="white"/&gt;
-  &lt;style tts:displayAlign="before"/&gt;
-  &lt;style tts:textAlign="end"/&gt;
-  &lt;style <phrase role="strong">tts:showBackground="whenActive"</phrase>/&gt;
-&lt;/region&gt;
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<!--
-<table id="style-attribute-showBackground-example-1-images" role="example-images">
-<caption>Example Rendition &ndash; Show Background</caption>
-<tbody>
-<tr>
-<td>
-<graphic source="images/showBackground.png" alt="TTML showBackground style property"/>
-</td>
-</tr>
-</tbody>
-</table>
--->
-<!-- CSS compatibility - remove derivation note
-<note role="derivation">
-<p>The semantics of the style property
-represented by this attribute are based upon that defined by <bibref ref="smil21"/>,
-&sect; 5.3.1.</p>
-</note>
--->
-</div3>
-<div3 id="style-attribute-textAlign">
-<head>tts:textAlign</head>
-<p>The <att>tts:textAlign</att> attribute is used to specify a style property that
-defines how inline areas are aligned within a containing block area in the inline progression
-direction.</p>
-<p>This attribute may be specified by any
-element type
-that permits use of attributes in the TT Style Namespace; however, this attribute applies
-as a style property only to those element types indicated in the following table.</p>
-<table id="style-property-details-textAlign" role="common">
-<col width="25%"/>
-<tbody>
-<tr>
-<td><emph>Values:</emph></td>
-<td>
-<code>left</code> |
-<code>center</code> |
-<code>right</code> |
-<code>start</code> |
-<code>end</code>
-</td>
-</tr>
-<tr>
-<td><emph>Initial:</emph></td>
-<td><code>start</code></td>
-</tr>
-<tr>
-<td><emph>Applies to:</emph></td>
-<td>
-<loc href="#content-vocabulary-p"><el>p</el></loc>
-</td>
-</tr>
-<tr>
-<td><emph>Inherited:</emph></td>
-<td>yes</td>
-</tr>
-<tr>
-<td><emph>Percentages:</emph></td>
-<td>N/A</td>
-</tr>
-<tr>
-<td><emph>Animatable:</emph></td>
-<td>discrete</td>
-</tr>
-</tbody>
-</table>
-<p>If a specified value of this attribute is not supported,
-then a presentation processor must interpret the attribute as if the
-value <code>start</code> were specified.</p>
-<p>The <att>tts:textAlign</att> style is illustrated by the following example.</p>
-<table id="style-attribute-textAlign-example-1" role="example">
-<caption>Example Fragment &ndash; Text Align</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;region xml:id="r1"&gt;
-  &lt;style tts:extent="355px 43px"/&gt;
-  &lt;style tts:origin="0px 0px"/&gt;
-  &lt;style tts:backgroundColor="black"/&gt;
-  &lt;style tts:color="white"/&gt;
-  &lt;style <phrase role="strong">tts:textAlign="start"</phrase>/&gt;
-&lt;/region&gt;
-&lt;region xml:id="r2"&gt;
-  &lt;style tts:extent="355px 43px"/&gt;
-  &lt;style tts:origin="0px 47px"/&gt;
-  &lt;style tts:backgroundColor="black"/&gt;
-  &lt;style tts:color="white"/&gt;
-  &lt;style <phrase role="strong">tts:textAlign="end"</phrase>/&gt;
-&lt;/region&gt;
-...
-&lt;p region="r1"&gt;
-  Beware the Jabberwock, my son!&lt;br/&gt;
-  The jaws that bite, the claws that catch!
-&lt;/p&gt;
-&lt;p region="r2"&gt;
-  Beware the Jubjub bird, and shun&lt;br/&gt;
-  The frumious Bandersnatch!
-&lt;/p&gt;
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p/>
-<table id="style-attribute-textAlign-example-1-images" role="example-images">
-<caption>Example Rendition &ndash; Text Align</caption>
-<tbody>
-<tr>
-<td><graphic source="images/textAlign.png" alt="TTML textAlign style property"/></td>
-</tr>
-</tbody>
-</table>
-<!--CSS compatibility - remove derivation note
-<note role="derivation">
-<p>The semantics of the style property
-represented by this attribute are based upon that defined by <bibref ref="xsl11"/>,
-&sect; 7.16.9.</p>
-</note>
--->
-</div3>
-<div3 id="style-attribute-textDecoration">
-<head>tts:textDecoration</head>
-<p>The <att>tts:textDecoration</att> attribute is used to specify a style property that
-defines a text decoration effect to apply to glyph areas or other inline
-areas that are generated by content flowed into a region.</p>
-<p>This attribute may be specified by any
-element type
-that permits use of attributes in the TT Style Namespace; however, this attribute applies
-as a style property only to those element types indicated in the following table.</p>
-<table id="style-property-details-textDecoration" role="common">
-<col width="25%"/>
-<tbody>
-<tr>
-<td><emph>Values:</emph></td>
-<td>
-<code>none</code> |
-[ [
-<code>underline</code> |
-<code>noUnderline</code>
-] || [
-<code>lineThrough</code> |
-<code>noLineThrough</code>
-] || [
-<code>overline</code> |
-<code>noOverline</code>
-] ]
-</td>
-</tr>
-<tr>
-<td><emph>Initial:</emph></td>
-<td><code>none</code></td>
-</tr>
-<tr>
-<td><emph>Applies to:</emph></td>
-<td><loc
-href="#content-vocabulary-span"><el>span</el></loc></td>
-</tr>
-<tr>
-<td><emph>Inherited:</emph></td>
-<td>yes</td>
-</tr>
-<tr>
-<td><emph>Percentages:</emph></td>
-<td>N/A</td>
-</tr>
-<tr>
-<td><emph>Animatable:</emph></td>
-<td>discrete</td>
-</tr>
-</tbody>
-</table>
-<p>For the purpose of determining applicability of this
-style property, each character child of a <el>p</el> element is
-considered to be enclosed in an anonymous span.</p>
-<p>If a specified value of this attribute is not supported,
-then a presentation processor must interpret the attribute as if the
-value <code>none</code> were specified.</p>
-<p>The <att>tts:textDecoration</att> style is illustrated by the following example.</p>
-<table id="style-attribute-textDecoration-example-1" role="example">
-<caption>Example Fragment &ndash; Text Decoration</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;region xml:id="r1"&gt;
-  &lt;style tts:extent="385px 82px"/&gt;
-  &lt;style tts:origin="0px 0px"/&gt;
-  &lt;style tts:backgroundColor="black"/&gt;
-  &lt;style tts:color="white"/&gt;
-  &lt;style tts:padding="5px 2px"/&gt;
-  &lt;style <phrase role="strong">tts:textDecoration="underline"</phrase>/&gt;
-&lt;/region&gt;
-...
-&lt;p region="r1"&gt;
-  The sea was wet&lt;span <phrase role="strong">tts:textDecoration="noUnderline"</phrase>&gt; as &lt;/span&gt;wet
-  &lt;span <phrase role="strong">tts:textDecoration="noUnderline"</phrase>&gt;
-    could be,&lt;br/&gt;
-    The sand was dry as dry.&lt;br/&gt;
-    &lt;span <phrase role="strong">tts:textDecoration="lineThrough"</phrase>&gt;There weren't any&lt;/span&gt;
-    You &lt;span <phrase role="strong">tts:textDecoration="lineThrough"</phrase>&gt;couldn't&lt;/span&gt;
-    could not see a cloud&lt;br/&gt;
-    Because no cloud was in the sky.
-  &lt;/span&gt;
-&lt;/p&gt;
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p/>
-<table id="style-attribute-textDecoration-example-1-images" role="example-images">
-<caption>Example Rendition &ndash; Text Decoration</caption>
-<tbody>
-<tr>
-<td><graphic source="images/textDecoration.png" alt="TTML textDecoration style property"/></td>
-</tr>
-</tbody>
-</table>
-<!--CSS compatibility - remove derivation note
-<note role="derivation">
-<p>The semantics of the style property
-represented by this attribute are based upon that defined by <bibref ref="xsl11"/>,
-&sect; 7.16.4.</p>
-</note>
--->  
-</div3>
-<div3 id="style-attribute-textOutline">
-<head>tts:textOutline</head>
-<p>The <att>tts:textOutline</att> attribute is used to specify a style property that
-defines a text outline effect to apply to glyphs that are selected for glyph areas generated
-by content flowed into a region.</p>
-<p>This attribute may be specified by any
-element type
-that permits use of attributes in the TT Style Namespace; however, this attribute applies
-as a style property only to those element types indicated in the following table.</p>
-<table id="style-property-details-textOutline" role="common">
-<col width="25%"/>
-<tbody>
-<tr>
-<td><emph>Values:</emph></td>
-<td>
-<code>none</code> |
-<loc href="#style-value-color">&lt;color&gt;</loc>?
-<loc href="#style-value-length">&lt;length&gt;</loc>
-<loc href="#style-value-length">&lt;length&gt;</loc>?
-</td>
-</tr>
-<tr>
-<td><emph>Initial:</emph></td>
-<td><code>none</code></td>
-</tr>
-<tr>
-<td><emph>Applies to:</emph></td>
-<td>
-<loc href="#content-vocabulary-span"><el>span</el></loc>
-</td>
-</tr>
-<tr>
-<td><emph>Inherited:</emph></td>
-<td>yes</td>
-</tr>
-<tr>
-<td><emph>Percentages:</emph></td>
-<td>relative to this element's font size</td>
-</tr>
-<tr>
-<td><emph>Animatable:</emph></td>
-<td>discrete</td>
-</tr>
-</tbody>
-</table>
-<p>For the purpose of determining applicability of this style property,
-each character child of a <el>p</el> element is considered to be enclosed in an anonymous
-span.</p>
-<p>The value of this attribute consists of an optional <loc href="#style-value-color">&lt;color&gt;</loc> term
-followed by one or two <loc href="#style-value-length">&lt;length&gt;</loc> terms.  If a <emph>color</emph> term is
-present, then it denotes the outline color; if no <emph>color</emph> term is
-present, the computed value of the <att>tts:color</att> applies.  The first
-<emph>length</emph> term denotes the outline thickness and the second length
-term, if present, indicates the blur radius.</p>
-<p>If a specified value of this attribute is not supported,
-then a presentation processor must interpret the attribute as if the
-value <code>none</code> were specified.</p>
-<p>The <att>tts:textOutline</att> style is illustrated by the following
-example.</p>
-<table id="style-attribute-textOutline-example-1" role="example">
-<caption>Example Fragment &ndash; Text Outline</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;region xml:id="r1"&gt;
-  &lt;style tts:backgroundColor="transparent"/&gt;
-  &lt;style tts:color="yellow"/&gt;
-  &lt;style <phrase role="strong">tts:textOutline="black 2px 0px"</phrase>/&gt;
-  &lt;style tts:fontFamily="proportionalSansSerif"/&gt;
-  &lt;style tts:fontSize="24px"/&gt;
-&lt;/region&gt;
-...
-&lt;p&gt;
-  How doth the little crocodile&lt;br/&gt;
-  Improve its shining tail,&lt;br/&gt;
-  And pour the waters of the Nile&lt;br/&gt;
-  On every golden scale!&lt;br/&gt;
-  How cheerfully he seems to grin,&lt;br/&gt;
-  How neatly spreads his claws,&lt;br/&gt;
-  And welcomes little fishes in,&lt;br/&gt;
-  With gently smiling jaws!
-&lt;/p&gt;
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p/>
-<table id="style-attribute-textOutline-example-1-images" role="example-images">
-<caption>Example Rendition &ndash; Text Outline</caption>
-<tbody>
-<tr>
-<td><graphic source="images/textOutline.png" alt="backgroundColor style property"/></td>
-</tr>
-</tbody>
-</table>
-</div3>
-<div3 id="style-attribute-unicodeBidi">
-<head>tts:unicodeBidi</head>
-<p>The <att>tts:unicodeBidi</att> attribute is used to specify a style property that
-defines a directional embedding or override according to
-the Unicode bidirectional algorithm.</p>
-<p>This attribute may be specified by any
-element type
-that permits use of attributes in the TT Style Namespace; however, this attribute applies
-as a style property only to those element types indicated in the following table.</p>
-<table id="style-property-details-unicodeBidi" role="common">
-<col width="25%"/>
-<tbody>
-<tr>
-<td><emph>Values:</emph></td>
-<td>
-<code>normal</code> |
-<code>embed</code> |
-<code>bidiOverride</code>
-</td>
-</tr>
-<tr>
-<td><emph>Initial:</emph></td>
-<td>
-<code>normal</code>
-</td>
-</tr>
-<tr>
-<td><emph>Applies to:</emph></td>
-<td>
-<loc href="#content-vocabulary-p"><el>p</el></loc>,
-<loc href="#content-vocabulary-span"><el>span</el></loc>
-</td>
-</tr>
-<tr>
-<td><emph>Inherited:</emph></td>
-<td>no</td>
-</tr>
-<tr>
-<td><emph>Percentages:</emph></td>
-<td>N/A</td>
-</tr>
-<tr>
-<td><emph>Animatable:</emph></td>
-<td>discrete</td>
-</tr>
-</tbody>
-</table>
-<p>For the purpose of determining applicability of this style property,
-each character child of a <el>p</el> element is considered to be enclosed in an anonymous
-span.</p>
-<p>If a specified value of this attribute is not supported,
-then a presentation processor must interpret the attribute as if the
-value <code>normal</code> were specified.</p>
-<p>The <att>tts:unicodeBidi</att> style is illustrated by the following example.</p>
-<table id="style-attribute-unicodeBidi-example-1" role="example">
-<caption>Example Fragment &ndash; Unicode Bidirectionality</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;region xml:id="r1"&gt;
-  &lt;style tts:extent="265px 84px"/&gt;
-  &lt;style tts:padding="5px"/&gt;
-  &lt;style tts:backgroundColor="black"/&gt;
-  &lt;style tts:color="white"/&gt;
-  &lt;style tts:displayAlign="after"/&gt;
-  &lt;style tts:textAlign="center"/&gt;
-&lt;/region&gt;
-...
-&lt;p region="r1"&gt;
-  Little birds are playing&lt;br/&gt;
-  Bagpipes on the shore,&lt;br/&gt;
-  &lt;span <phrase role="strong">tts:unicodeBidi="bidiOverride"</phrase> tts:direction="rtl"&gt;where the tourists snore.&lt;/span&gt;
-&lt;/p&gt;
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p/>
-<table id="style-attribute-unicodeBidi-example-1-images" role="example-images">
-<caption>Example Rendition &ndash; Unicode Bidirectionality</caption>
-<tbody>
-<tr>
-<td>
-<graphic source="images/unicodeBidi.png" alt="TTML unicodeBidi style property"/>
-</td>
-</tr>
-</tbody>
-</table>
-<!-- CSS compatibility - remove derivation note
-<note role="derivation">
-<p>The semantics of the style property
-represented by this attribute are based upon that defined by <bibref ref="xsl11"/>,
-&sect; 7.29.6.</p>
-</note>
--->
-</div3>
-<div3 id="style-attribute-visibility">
-<head>tts:visibility</head>
-<p>The <att>tts:visibility</att> attribute is used to specify a style property that
-defines whether generated areas are visible or not when rendered on a visual
-presentation medium.</p>
-<p>This attribute may be specified by any
-element type
-that permits use of attributes in the TT Style Namespace; however, this attribute applies
-as a style property only to those element types indicated in the following table.</p>
-<table id="style-property-details-visibility" role="common">
-<col width="25%"/>
-<tbody>
-<tr>
-<td><emph>Values:</emph></td>
-<td>
-<code>visible</code> |
-<code>hidden</code>
-</td>
-</tr>
-<tr>
-<td><emph>Initial:</emph></td>
-<td>
-<code>visible</code>
-</td>
-</tr>
-<tr>
-<td><emph>Applies to:</emph></td>
-<td>
-<loc href="#document-structure-vocabulary-body"><el>body</el></loc>,
-<loc href="#content-vocabulary-div"><el>div</el></loc>,
-<loc href="#content-vocabulary-p"><el>p</el></loc>,
-<loc href="#layout-vocabulary-region"><el>region</el></loc>,
-<loc href="#content-vocabulary-span"><el>span</el></loc>
-</td>
-</tr>
-<tr>
-<td><emph>Inherited:</emph></td>
-<td>yes</td>
-</tr>
-<tr>
-<td><emph>Percentages:</emph></td>
-<td>N/A</td>
-</tr>
-<tr>
-<td><emph>Animatable:</emph></td>
-<td>discrete</td>
-</tr>
-</tbody>
-</table>
-<p>For the purpose of determining applicability of this style property,
-each character child of a <el>p</el> element is considered to be enclosed in an anonymous
-span.</p>
-<p>The <att>tts:visibility</att> style has no affect on content layout or
-composition, but merely determines whether composed content is visible or not.</p>
-<p>If a specified value of this attribute is not supported,
-then a presentation processor must interpret the attribute as if the
-value <code>visible</code> were specified.</p>
-<p>The <att>tts:visibility</att> style is illustrated by the following example.</p>
-<table id="style-attribute-visibility-example-1" role="example">
-<caption>Example Fragment &ndash; Visibility</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;region xml:id="r1"&gt;
-  &lt;style tts:extent="398px 121px"/&gt;
-  &lt;style tts:backgroundColor="black"/&gt;
-  &lt;style tts:color="white"/&gt;
-  &lt;style/&gt;
-&lt;/region&gt;
-...
-&lt;p region="r1" dur="4s"&gt;
-  &lt;span <phrase role="strong">tts:visibility="hidden"</phrase>&gt;
-    &lt;set begin="1s" <phrase role="strong">tts:visibility="visible"</phrase>/&gt;
-    Curiouser
-  &lt;/span&gt;
-  &lt;span <phrase role="strong">tts:visibility="hidden"</phrase>&gt;
-    &lt;set begin="2s" <phrase role="strong">tts:visibility="visible"</phrase>/&gt;
-    and
-  &lt;/span&gt;
-  &lt;span <phrase role="strong">tts:visibility="hidden"</phrase>&gt;
-    &lt;set begin="3s" <phrase role="strong">tts:visibility="visible"</phrase>/&gt;
-    curiouser!
-  &lt;/span&gt;
-&lt;/p&gt;
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p/>
-<table id="style-attribute-visibility-example-1-images" role="example-images">
-<caption>Example Rendition &ndash; Visibility</caption>
-<tbody>
-<tr>
-<td>
-<graphic source="images/visibility_0.png" alt="TTML visibility style property - [0,1)"/>
-</td>
-</tr>
-<tr>
-<td>
-<graphic source="images/visibility_1.png" alt="TTML visibility style property - [1,2)"/>
-</td>
-</tr>
-<tr>
-<td>
-<graphic source="images/visibility_2.png" alt="TTML visibility style property - [2,3)"/>
-</td>
-</tr>
-<tr>
-<td>
-<graphic source="images/visibility_3.png" alt="TTML visibility style property - [3,4)"/>
-</td>
-</tr>
-</tbody>
-</table>
-<!-- CSS compatibility - remove derivation note
-  <note role="derivation">
-<p>The semantics of the style property
-represented by this attribute are based upon that defined by <bibref ref="xsl11"/>,
-&sect; 7.28.8.</p>
-</note>
--->
-</div3>
-<div3 id="style-attribute-wrapOption">
-<head>tts:wrapOption</head>
-<p>The <att>tts:wrapOption</att> attribute is used to specify a style property that
-defines whether or not automatic line wrapping (breaking) applies within the context of
-the affected element.</p>
-<p>This attribute may be specified by any
-element type
-that permits use of attributes in the TT Style Namespace; however, this attribute applies
-as a style property only to those element types indicated in the following table.</p>
-<table id="style-property-details-wrapOption" role="common">
-<col width="25%"/>
-<tbody>
-<tr>
-<td><emph>Values:</emph></td>
-<td>
-<code>wrap</code> |
-<code>noWrap</code>
-</td>
-</tr>
-<tr>
-<td><emph>Initial:</emph></td>
-<td><code>wrap</code></td>
-</tr>
-<tr>
-<td><emph>Applies to:</emph></td>
-<td>
-<loc href="#content-vocabulary-span"><el>span</el></loc>
-</td>
-</tr>
-<tr>
-<td><emph>Inherited:</emph></td>
-<td>yes</td>
-</tr>
-<tr>
-<td><emph>Percentages:</emph></td>
-<td>N/A</td>
-</tr>
-<tr>
-<td><emph>Animatable:</emph></td>
-<td>discrete</td>
-</tr>
-</tbody>
-</table>
-<p>For the purpose of determining applicability of this style property,
-each character child of a <el>p</el> element is considered to be enclosed in an anonymous
-span.</p>
-<p>If a specified value of this attribute is not supported,
-then a presentation processor must interpret the attribute as if the
-value <code>wrap</code> were specified.</p>
-<p>The <att>tts:wrapOption</att> style is illustrated by the following example.</p>
-<table id="style-attribute-wrapOption-example-1" role="example">
-<caption>Example Fragment &ndash; Wrap Option</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;region xml:id="r1"&gt;
-  &lt;style tts:extent="192px 117px"/&gt;
-  &lt;style tts:backgroundColor="black"/&gt;
-  &lt;style tts:color="white"/&gt;
-  &lt;style tts:displayAlign="after"/&gt;
-  &lt;style tts:overflow="hidden"/&gt;
-  &lt;style <phrase role="strong">tts:wrapOption="noWrap"</phrase>/&gt;
-&lt;/region&gt;
-...
-&lt;p&gt;
-  I'll tell thee everything I can:&lt;br/&gt;
-  There's little to relate.&lt;br/&gt;
-  I saw an aged aged man,&lt;br/&gt;
-  A-sitting on a gate.
-&lt;/p&gt;
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p/>
-<table id="style-attribute-wrapOption-example-1-images" role="example-images">
-<caption>Example Rendition &ndash; Wrap Option</caption>
-<tbody>
-<tr>
-<td><graphic source="images/wrapOption.png" alt="TTML wrapOption style property"/></td>
-</tr>
-</tbody>
-</table>
-  <!-- CSS compatibility - remove derivation note
-<note role="derivation">
-<p>The semantics of the style property
-represented by this attribute are based upon that defined by <bibref ref="xsl11"/>,
-&sect; 7.15.13.</p>
-</note>
--->
-</div3>
-<div3 id="style-attribute-writingMode">
-<head>tts:writingMode</head>
-<p>The <att>tts:writingMode</att> attribute is used to specify a style property that
-defines the block and inline progression directions to be used for the purpose of
-stacking block and inline areas within a region area.</p>
-<p>This attribute may be specified by any
-element type
-that permits use of attributes in the TT Style Namespace; however, this attribute applies
-as a style property only to those element types indicated in the following table.</p>
-<table id="style-property-details-writingMode" role="common">
-<col width="25%"/>
-<tbody>
-<tr>
-<td><emph>Values:</emph></td>
-<td>
-<code>lrtb</code> |
-<code>rltb</code> |
-<code>tbrl</code> |
-<code>tblr</code> |
-<code>lr</code> |
-<code>rl</code> |
-<code>tb</code>
-</td>
-</tr>
-<tr>
-<td><emph>Initial:</emph></td>
-<td><code>lrtb</code></td>
-</tr>
-<tr>
-<td><emph>Applies to:</emph></td>
-<td>
-<loc href="#layout-vocabulary-region"><el>region</el></loc>
-</td>
-</tr>
-<tr>
-<td><emph>Inherited:</emph></td>
-<td>no</td>
-</tr>
-<tr>
-<td><emph>Percentages:</emph></td>
-<td>N/A</td>
-</tr>
-<tr>
-<td><emph>Animatable:</emph></td>
-<td>discrete</td>
-</tr>
-</tbody>
-</table>
-<p>If a specified value of this attribute is not supported,
-then a presentation processor must interpret the attribute as if the
-value <code>lrtb</code> were specified.</p>
-<p>The <att>tts:writingMode</att> style is illustrated by the following example.</p>
-<table id="style-attribute-writingMode-example-1" role="example">
-<caption>Example Fragment &ndash; Writing Mode</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;region xml:id="r1"&gt;
-  &lt;style tts:extent="50px 570px"/&gt;
-  &lt;style tts:origin="0px 0px"/&gt;
-  &lt;style tts:padding="10px 3px"/&gt;
-  &lt;style tts:backgroundColor="black"/&gt;
-  &lt;style tts:color="white"/&gt;
-  &lt;style <phrase role="strong">tts:writingMode="tbrl"</phrase>/&gt;
-&lt;/region&gt;
-&lt;region xml:id="r2"&gt;
-  &lt;style tts:extent="310px 50px"/&gt;
-  &lt;style tts:origin="70px 120px"/&gt;
-  &lt;style tts:padding="10px 3px"/&gt;
-  &lt;style tts:backgroundColor="black"/&gt;
-  &lt;style tts:color="white"/&gt;
-  &lt;style <phrase role="strong">tts:writingMode="rltb"</phrase>/&gt;
-&lt;/region&gt;
-...
-&lt;p region="r1"&gt;
-  I sometimes dig for buttered rolls,&lt;br/&gt;
-  Or set limed twigs for crabs:
-&lt;/p&gt;
-&lt;p region="r2" tts:direction="rtl" tts:unicodeBidi="bidiOverride"&gt;
-  I sometimes search the grassy knolls for the wheels of Hansom-cabs.
-&lt;/p&gt;
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p/>
-<table id="style-attribute-writingMode-example-1-images" role="example-images">
-<caption>Example Rendition &ndash; Writing Mode</caption>
-<tbody>
-<tr>
-<td><graphic source="images/writingMode.png" alt="TTML writingMode style property"/></td>
-</tr>
-</tbody>
-</table>
-<note role="explanation">
-<p>In the second paragraph in the above example that targets region
-<code>r2</code>, the <att>tts:unicodeBidi</att> and
-<att>tts:direction</att> properties are set to
-<code>bidiOverride</code> and <code>rtl</code>, respectively, in order
-to override the normally left-to-right directionality of characters in
-the Latin script.</p>
-</note>
-<!-- CSS compatibility - remove derivation note 
-<note role="derivation">
-<p>The semantics of the style property
-represented by this attribute are based upon that defined by <bibref ref="xsl11"/>,
-&sect; 7.27.7.</p>
-</note>
-  -->
-</div3>
-<div3 id="style-attribute-zIndex">
-<head>tts:zIndex</head>
-<p>The <att>tts:zIndex</att> attribute is used to specify a style property that
-defines the front-to-back ordering of region areas in the case that they overlap.</p>
-<p>This attribute may be specified by any
-element type
-that permits use of attributes in the TT Style Namespace; however, this attribute applies
-as a style property only to those element types indicated in the following table.</p>
-<table id="style-property-details-zIndex" role="common">
-<col width="25%"/>
-<tbody>
-<tr>
-<td><emph>Values:</emph></td>
-<td>
-<code>auto</code> |
-<loc href="#style-value-integer">&lt;integer&gt;</loc>
-</td>
-</tr>
-<tr>
-<td><emph>Initial:</emph></td>
-<td><code>auto</code></td>
-</tr>
-<tr>
-<td><emph>Applies to:</emph></td>
-<td>
-<loc href="#layout-vocabulary-region"><el>region</el></loc>
-</td>
-</tr>
-<tr>
-<td><emph>Inherited:</emph></td>
-<td>no</td>
-</tr>
-<tr>
-<td><emph>Percentages:</emph></td>
-<td>N/A</td>
-</tr>
-<tr>
-<td><emph>Animatable:</emph></td>
-<td>discrete</td>
-</tr>
-</tbody>
-</table>
-<p>If two areas are associated with the same Z-index value, then, if those areas
-overlap in space, the area(s) generated by lexically subsequent elements must be
-rendered over area(s) generated by lexically prior elements, where lexical
-order is defined as the postorder traversal of a document
-instance.</p>
-<p>The semantics of the value <code>auto</code> are those defined by
-<bibref ref="xsl11"/>, &sect; 7.30.18, where the <el>tt</el> element
-is considered to establish the root stacking context.</p>
-<p>If a specified value of this attribute is not supported,
-then a presentation processor must interpret the attribute as if the
-value <code>auto</code> were specified.</p>
-<p>The <att>tts:zIndex</att> style is illustrated by the following example.</p>
-<table id="style-attribute-zIndex-example-1" role="example">
-<caption>Example Fragment &ndash; Z Index</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;region xml:id="r1"&gt;
-  &lt;style tts:origin="0px 0px"/&gt;
-  &lt;style tts:extent="400px 100px"/&gt;
-  &lt;style tts:padding="5px"/&gt;
-  &lt;style tts:backgroundColor="black"/&gt;
-  &lt;style tts:color="white"/&gt;
-  &lt;style <phrase role="strong">tts:zIndex="0"</phrase>/&gt;
-&lt;/region&gt;
-&lt;region xml:id="r2"&gt;
-  &lt;style tts:origin="100px 60px"/&gt;
-  &lt;style tts:extent="400px 100px"/&gt;
-  &lt;style tts:padding="5px"/&gt;
-  &lt;style tts:backgroundColor="red"/&gt;
-  &lt;style tts:color="white"/&gt;
-  &lt;style tts:textAlign="end"/&gt;
-  &lt;style <phrase role="strong">tts:zIndex="1"</phrase>/&gt;
-&lt;/region&gt;
-&lt;region xml:id="r3"&gt;
-  &lt;style tts:origin="0px 120px"/&gt;
-  &lt;style tts:extent="400px 100px"/&gt;
-  &lt;style tts:padding="5px"/&gt;
-  &lt;style tts:backgroundColor="black"/&gt;
-  &lt;style tts:color="white"/&gt;
-  &lt;style <phrase role="strong">tts:zIndex="2"</phrase>/&gt;
-&lt;/region&gt;
-&lt;region xml:id="r4"&gt;
-  &lt;style tts:origin="100px 180px"/&gt;
-  &lt;style tts:extent="400px 100px"/&gt;
-  &lt;style tts:padding="5px"/&gt;
-  &lt;style tts:backgroundColor="red"/&gt;
-  &lt;style tts:color="white"/&gt;
-  &lt;style tts:textAlign="end"/&gt;
-  &lt;style <phrase role="strong">tts:zIndex="3"</phrase>/&gt;
-&lt;/region&gt;
-...
-&lt;p region="r1"&gt;
-  I passed by his garden, and marked, with one eye,&lt;br/&gt;
-  How the Owl and the Panther were sharing a pie.
-&lt;/p&gt;
-&lt;p region="r2"&gt;
-  The Panther took pie-crust, and gravy, and meat,&lt;br/&gt;
-  While the Owl had the dish as its share of the treat.
-&lt;/p&gt;
-&lt;p region="r3"&gt;
-  When the pie was all finished, the Owl, as a boon,&lt;br/&gt;
-  Was kindly permitted to pocket the spoon:
-&lt;/p&gt;
-&lt;p region="r4"&gt;
-  While the Panther received knife and fork&lt;br/&gt;
-  with a growl,&lt;br/&gt;
-  And concluded the banquet by...
-&lt;/p&gt;
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p/>
-<p/>
-<table id="style-attribute-zIndex-example-1-images" role="example-images">
-<caption>Example Rendition &ndash; Z Index</caption>
-<tbody>
-<tr>
-<td><graphic source="images/zIndex.png" alt="TTML zIndex style property"/></td>
-</tr>
-</tbody>
-</table>
-<!-- CSS compatibility - remove derivation note
-<note role="derivation">
-<p>The semantics of the style property
-represented by this attribute are based upon that defined by <bibref ref="xsl11"/>,
-&sect; 7.28.9.</p>
-</note>
--->
-</div3>
-</div2>
-<div2 id="styling-style-value-expressions">
-<head>Style Value Expressions</head>
-<p>Style property values include the use of the following expressions:</p>
-<ulist>
-<item><p><specref ref="style-value-alpha"/></p></item>
-<item><p><specref ref="style-value-color"/></p></item>
-<item><p><specref ref="style-value-digit"/></p></item>
-<item><p><specref ref="style-value-duration"/></p></item>
-<item><p><specref ref="style-value-familyName"/></p></item>
-<item><p><specref ref="style-value-genericFamilyName"/></p></item>
-<item><p><specref ref="style-value-hexDigit"/></p></item>
-<item><p><specref ref="style-value-integer"/></p></item>
-<item><p><specref ref="style-value-length"/></p></item>
-<item><p><specref ref="style-value-namedColor"/></p></item>
-<item><p><specref ref="style-value-quotedString"/></p></item>
-<item><p><specref ref="style-value-string"/></p></item>
-</ulist>
-<div3 id="style-value-alpha">
-<head>&lt;alpha&gt;</head>
-<p>An &lt;alpha&gt; expression is used to express an opacity value,
-where	0 means fully transparent and 1 means fully opaque.</p>
-<table id="alpha-style-expression-syntax" role="syntax">
-<caption>Syntax Representation &ndash; &lt;alpha&gt;</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;alpha&gt;
-  : <emph>float</emph>
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p>In the above syntax representation, the syntactic element
-<emph><code>float</code></emph> must adhere to the lexical
-representation defined by <bibref ref="xsd-2"/>&nbsp;&sect;
-3.2.4.1. If the value represented is less than 0.0,
-then it must be interpreted as equal to 0.0; similarly, if the value
-represented is greater than 1.0, then it must be interpreted as
-1.0. The value NaN shall be interpreted as 0.0.</p>
-<p>If a presentation processor does not support a specific,
-valid opacity value, then it must interpret it as being equal to the
-closest supported value.</p>
-</div3>
-<div3 id="style-value-color">
-<head>&lt;color&gt;</head>
-<p>A &lt;color&gt; expression is used to specify a named color, exact RGB color triple,
-or exact RGBA color tuple, where the alpha component, if expressed,
-is maximum (255) at 100% opacity
-and minimum (0) at 0% opacity, and where the applicable color space is
-defined by <bibref ref="srgb"/>.</p>
-<table id="color-style-expression-syntax" role="syntax">
-<caption>Syntax Representation &ndash; &lt;color&gt;</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;color&gt;
-  : "#" rrggbb
-  | "#" rrggbbaa
-  | "rgb" "(" r-value "," g-value "," b-value ")"
-  | "rgba" "(" r-value "," g-value "," b-value "," a-value ")"
-  | <loc href="#style-value-namedColor">&lt;namedColor&gt;</loc>
-
-rrggbb
-  :  <loc href="#style-value-hexDigit">&lt;hexDigit&gt;</loc>{6}
-
-rrggbbaa
-  :  <loc href="#style-value-hexDigit">&lt;hexDigit&gt;</loc>{8}
-
-r-value | g-value | b-value | a-value
-  : component-value
-
-component-value
-  : non-negative-integer                    // valid range: [0,255]
-
-non-negative-integer
-  : <loc href="#style-value-digit">&lt;digit&gt;</loc>+
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p>When expressing RGB component values, these values are considered
-to <phrase role="strong">not</phrase> be premultiplied by alpha.</p>
-<p>For the purpose of performing presentation processing such that
-non-opaque or non-transparent alpha or opacity values apply, then the
-semantics of compositing functions are defined with respect to the use of
-the <bibref ref="srgb"/> color space for both inputs and outputs of
-the composition function.</p>
-<note role="clarification">
-<p>The use of <bibref ref="srgb"/> for the stated semantics of
-composition is not meant to prevent an actual processor from using some
-other color space either for internal or external purposes. For
-example, a presentation processor may ultimately convert the SRGB values
-used here to the YUV color space for rendition on a television device.</p>
-</note>
-<p>If a presentation processor does not support a specific,
-valid color or alpha value, then it must interpret it as being equal
-to the closest supported value.</p>
-</div3>
-<div3 id="style-value-digit">
-<head>&lt;digit&gt;</head>
-<p>A &lt;digit&gt; is used to express integers and other types of numbers or tokens.</p>
-<table id="digit-style-expression-syntax" role="syntax">
-<caption>Syntax Representation &ndash; &lt;digit&gt;</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;digit&gt;
-  : "0" | "1" | "2" | "3" | "4" | "5" | "6" | "7" | "8" | "9"
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-</div3>
-<div3 id="style-value-duration">
-<head>&lt;duration&gt;</head>
-<p>A &lt;duration&gt; expression is used to express a temporal duration value.</p>
-<table id="duration-style-expression-syntax" role="syntax">
-<caption>Syntax Representation &ndash; &lt;duration&gt;</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;duration&gt;
-  : <loc href="#style-value-digit">&lt;digit&gt;</loc>+ ( "." <loc href="#style-value-digit">&lt;digit&gt;</loc>+ )? metric
-
-metric
-  : "s"                 // seconds
-  | "ms"                // milliseconds
-  | "f"                 // frames
-  | "t"                 // ticks
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p>It is an error to omit the metric component of a duration.</p>
-<p>When operating with <code>smpte</code> time base and
-<code>discontinuous</code> mode, a duration expression must be
-considered to denote a duration in (local) real-time, independently of the
-governing time base.</p>
-</div3>
-<div3 id="style-value-familyName">
-<head>&lt;familyName&gt;</head>
-<p>A &lt;familyName&gt; expression specifies a font family name.</p>
-<p>If the name contains a quotation delimiter character,
-then it must be expressed as a
-&lt;quotedString&gt;. If the name contains a
-whitespace character,
-then it should be expressed as a
-&lt;quotedString&gt;; however, if it is expressed as a &lt;string&gt;, then it
-must not contain a <code>COMMA</code> ',' character.</p>
-
-<table id="familyName-style-expression-syntax" role="syntax">
-<caption>Syntax Representation &ndash; &lt;familyName&gt;</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;familyName&gt;
-  : <loc href="#style-value-string">&lt;string&gt;</loc>
-  | <loc href="#style-value-quotedString">&lt;quotedString&gt;</loc>
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-</div3>
-<div3 id="style-value-genericFamilyName">
-<head>&lt;genericFamilyName&gt;</head>
-<p>A &lt;genericFamilyName&gt; expression specifies a font family using a general
-token that indicates a class of font families.</p>
-<p>The resolution of a generic family name to a concrete font instance is considered to
-be implementation dependent, both in the case of content authoring and content interpretation.</p>
-<table id="genericFamilyName-style-expression-syntax" role="syntax">
-<caption>Syntax Representation &ndash; &lt;genericFamilyName&gt;</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;genericFamilyName&gt;
-  : "default"
-  | "monospace"
-  | "sansSerif"
-  | "serif"
-  | "monospaceSansSerif"
-  | "monospaceSerif"
-  | "proportionalSansSerif"
-  | "proportionalSerif"
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p>The mapping between a generic (font) family name and an actual font is not
-determined by this specification; however, the
-distinction of monospace versus proportional and serif versus sans-serif
-should be maintained if possible when performing presentation.</p>
-<p>If a generic (font) family name of <code>monospace</code> is specified,
-then it may be interpreted as equivalent to either <code>monospaceSansSerif</code>
-or <code>monospaceSerif</code>. The generic family names <code>sansSerif</code>
-and <code>serif</code> are to be interpreted as equivalent to <code>proportionalSansSerif</code>
-and <code>proportionalSerif</code>, respectively.</p>
-<p>If the generic family name <code>default</code> is specified (or implied by
-an initial value), then its typographic characteristics is considered to be implementation
-dependent; however, it is recommended that this default font family be mapped to
-an monospaced, sans-serif font.</p>
-</div3>
-<div3 id="style-value-hexDigit">
-<head>&lt;hexDigit&gt;</head>
-<p>A &lt;hexDigit&gt; is used to express integers and other types of numbers or tokens
-that employ base 16 arithmetic.</p>
-<p>For the purpose of parsing, no distinction must be made between lower and upper case.</p>
-<table id="hexDigit-style-expression-syntax" role="syntax">
-<caption>Syntax Representation &ndash; &lt;hexDigit&gt;</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;hexDigit&gt;
-  : <loc href="#style-value-digit">&lt;digit&gt;</loc>
-  | "a" | "b" | "c" | "d" | "e" | "f"
-  | "A" | "B" | "C" | "D" | "E" | "F"
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-</div3>
-<div3 id="style-value-integer">
-<head>&lt;integer&gt;</head>
-<p>An &lt;integer&gt; expression is used to express an arbitrary, signed integral value.</p>
-<table id="integer-style-expression-syntax" role="syntax">
-<caption>Syntax Representation &ndash; &lt;integer&gt;</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;integer&gt;
-  : ( "+" | "-" )? <loc href="#style-value-digit">&lt;digit&gt;</loc>+
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-</div3>
-<div3 id="style-value-length">
-<head>&lt;length&gt;</head>
-<p>A &lt;length&gt; expression is used to express either a coordinate component of point
-in a cartesian space or a distance between two points in a cartesian space.</p>
-<table id="length-style-expression-syntax" role="syntax">
-<caption>Syntax Representation &ndash; &lt;length&gt;</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;length&gt;
-  : scalar
-  | percentage
-
-scalar
-  : number units
-
-percentage
-  : number "%"
-
-sign
-  : "+" | "-"
-
-number
-  : sign? non-negative-number
-
-non-negative-number
-  : non-negative-integer
-  | non-negative-real
-
-non-negative-integer
-  : <loc href="#style-value-digit">&lt;digit&gt;</loc>+
-
-non-negative-real
-  : <loc href="#style-value-digit">&lt;digit&gt;</loc>* "." <loc href="#style-value-digit">&lt;digit&gt;</loc>+
-
-units
-  : "px"
-  | "em"
-  | "c"                                     // abbreviation of "cell"
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p>It is an error to omit the units component of a scalar length
-value.</p>
-<p>The semantics of
-the unit of measure <code>px</code> (pixel) 
-are as defined by <bibref ref="xsl11"/>, &sect; 5.9.13.</p>
-<p>When specified relative to a font whose size is expressed as a single length
-measure or as two length measures of equal length, the unit of measure <code>em</code> is considered to be
-identical to that defined by <bibref ref="xsl11"/>, &sect; 5.9.13;
-however, when specified relative to a font whose size is expressed as
-two length measures of non-equal lengths, then one <code>em</code> is
-equal to the inline progression dimension of the anamorphically
-scaled font when used to specify lengths in the inline progression
-direction and equal to the block progression dimension of the scaled
-font when used to specify lengths in the block progression direction.</p>
-<p>The semantics of the unit of measure <code>c</code> (cell) are
-defined by the parameter <specref
-ref="parameter-attribute-cellResolution"/>.</p>
-</div3>
-<div3 id="style-value-namedColor">
-<head>&lt;namedColor&gt;</head>
-<p>A &lt;namedColor&gt; is used to express an RGBA color with a convenient name, and where the applicable color space is
-defined by <bibref ref="srgb"/>.</p>
-<p>For the purpose of parsing, no distinction must be made between lower and upper case.</p>
-<table id="namedColor-style-expression-syntax" role="syntax">
-<caption>Syntax Representation &ndash; &lt;namedColor&gt;</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;namedColor&gt;
-  : "transparent"                           // #00000000
-  | "black"                                 // #000000ff
-  | "silver"                                // #c0c0c0ff
-  | "gray"                                  // #808080ff
-  | "white"                                 // #ffffffff
-  | "maroon"                                // #800000ff
-  | "red"                                   // #ff0000ff
-  | "purple"                                // #800080ff
-  | "fuchsia"                               // #ff00ffff
-  | "magenta"                               // #ff00ffff (= fuchsia)
-  | "green"                                 // #008000ff
-  | "lime"                                  // #00ff00ff
-  | "olive"                                 // #808000ff
-  | "yellow"                                // #ffff00ff
-  | "navy"                                  // #000080ff
-  | "blue"                                  // #0000ffff
-  | "teal"                                  // #008080ff
-  | "aqua"                                  // #00ffffff
-  | "cyan"                                  // #00ffffff (= aqua)
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<note role="clarification">
-<p>Except for <code>transparent</code>, the set of named colors specified above constitutes a proper
-subset of the set of named colors specified by <bibref ref="svg11"/>, &sect; 4.2.</p>
-</note>
-</div3>
-<div3 id="style-value-quotedString">
-<head>&lt;quotedString&gt;</head>
-<p>A &lt;quotedString&gt; is used to express a delimited string that may contain
-a whitespace or a quotation delimiter character. Two types of quotation delimiters
-are provided in order to accommodate strings that contain the other delimiter.</p>
-<table id="quotedString-style-expression-syntax" role="syntax">
-<caption>Syntax Representation &ndash; &lt;quotedString&gt;</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;quotedString&gt;
-  : "\"" ( <emph>char</emph> - { "\"" } )* "\""
-  | "\'" ( <emph>char</emph> - { "\'" } )* "\'"
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p>In the above syntax representation, the syntactic element <emph><code>char</code></emph> must adhere to production
-[2] <code>Char</code> as defined by <bibref ref="xml10"/>&nbsp;&sect;
-2.2.</p>
-</div3>
-<div3 id="style-value-string">
-<head>&lt;string&gt;</head>
-<p>A &lt;string&gt; expression consists of a sequence of characters where no character
-is a quotation delimiter character.</p>
-<table id="string-style-expression-syntax" role="syntax">
-<caption>Syntax Representation &ndash; &lt;string&gt;</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;string&gt;
-  : ( <emph>char</emph> - { "\"" | "\'" } )+
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p>In the above syntax representation, the syntactic element <emph><code>char</code></emph> must adhere to production
-[2] <code>Char</code> as defined by <bibref ref="xml10"/>&nbsp;&sect;
-2.2.</p>
-</div3>
-</div2>
-<div2 id="semantics-style-resolution">
-<head>Style Resolution</head>
-<p>This section defines the semantics of style resolution in terms of
-a standard processing model as follows:</p>
-<ulist>
-<item><p><specref ref="semantics-style-association"/></p></item>
-<item><p><specref ref="semantics-style-inheritance"/></p></item>
-<item><p><specref ref="semantics-style-resolution-value-categories"/></p></item>
-<item><p><specref ref="semantics-style-resolution-processing"/></p></item>
-</ulist>
-<p>Any implementation of this model is permitted provided that the
-externally observable results are consistent with the results produced
-by this model.</p>
-<note role="derivation">
-<p>The semantics of style resolution employed here are based upon
-<bibref ref="xsl11"/>, &sect; 5.</p>
-</note>
-<div3 id="semantics-style-association">
-<head>Style Association</head>
-<p>Style association is a sub-process of <specref
-ref="semantics-style-resolution-processing"/> used to determine the
-specified style set of each content and
-layout element.</p>
-<p>Style matter may be associated with content
- and layout matter in a number of ways:</p>
-<ulist>
-<item><p><loc href="#semantics-style-association-inline">inline styling</loc></p></item>
-<item><p><loc href="#semantics-style-association-referential">referential styling</loc></p></item>
-<item><p><loc href="#semantics-style-association-chained-referential">chained referential styling</loc></p></item>
-</ulist>
-<p>In addition to the above, style matter may be associated with layout matter using:</p>
-<ulist>
-<item><p><loc href="#semantics-style-association-nested">nested styling</loc></p></item>
-</ulist>
-<div4 id="semantics-style-association-inline">
-<head>Inline Styling</head>
-<p>Style properties may be expressed in an inline manner by direct
-specification of an attribute from the TT Style Namespace on the
-affected element. When expressed in this manner, the association of
-style information is referred to as <emph>inline styling</emph>.</p>
-<p>Style properties associated by inline styling are afforded a higher priority than all other
-forms of style association.</p>
-<table id="style-association-example-1" role="example">
-<caption>Example &ndash; Inline Styling</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;p <phrase role="strong">tts:color="white"</phrase>&gt;White 1&nbsp;&lt;span <phrase role="strong">tts:color="yellow"</phrase>&gt;Yellow&lt;/span&gt;&nbsp;White 2&lt;/p&gt;
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<note role="explanation">
-<p>In the above example, the two text fragments <code>"White 1 "</code> and
-<code>" White 2"</code>, which are interpreted as anonymous spans, are not
-associated with a color style property; rather, they inherit their color style
-from their parent <el>p</el> element as described in <specref
-ref="semantics-style-inheritance-content"/> below.  </p>
-</note>
-</div4>
-<div4 id="semantics-style-association-referential">
-<head>Referential Styling</head>
-<p>Style properties may be expressed in an out-of-line manner and referenced by the
-affected element using the <att>style</att> attribute. When expressed in this manner,
-the association of style information is referred to as <emph>referential styling</emph>.</p>
-<p>If a <att>style</att> attribute specifies multiple references, then those references are
-evaluated in the specified order, and that order applies to resolution of the value of a
-style property in the case that it is specified along multiple reference paths.</p>
-<p>The use of referential styling is restricted to making
-reference to <el>style</el> element descendants of a <el>styling</el>
-element. It is considered an error to reference a <el>style</el>
-element that is a descendant of a <el>layout</el> element.</p>
-<note role="explanation">
-<p>The use of referential styling encourages the reuse of style specifications while
-sacrificing locality of reference.</p>
-</note>
-<note role="explanation">
-<p>A single content element may be associated with style properties by a hybrid mixture of
-inline and referential styling, in which case inline styling is given priority as described above
-by <specref ref="semantics-style-association-inline"/>.</p>
-</note>
-<table id="style-association-example-2" role="example">
-<caption>Example &ndash; Referential Styling</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;style <phrase role="strong">xml:id="s1"</phrase> tts:color="white"/&gt;
-&lt;style <phrase role="strong">xml:id="s2"</phrase> tts:color="yellow"/&gt;
-...
-&lt;p <phrase role="strong">style="s1"</phrase>&gt;White 1&nbsp;&lt;span <phrase role="strong">style="s2"</phrase>&gt;Yellow&lt;/span&gt;&nbsp;White 2&lt;/p&gt;
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<note role="explanation">
-<p>In the above example, the two text fragments <code>"White 1 "</code> and
-<code>" White 2"</code>, which are interpreted as anonymous spans, are not
-associated with a color style property; rather, they inherit their color style
-from their parent <el>p</el> element as described in <specref
-ref="semantics-style-inheritance-content"/> below.</p>
-</note>
-</div4>
-<div4 id="semantics-style-association-chained-referential">
-<head>Chained Referential Styling</head>
-<p>Style properties may be expressed in an out-of-line manner and may themselves reference
-other out-of-line style properties, thus creating a chain of references starting at the
-affected element. When expressed in this manner, the association of style information
-is referred to as <emph>chained referential styling</emph>.</p>
-<p>If the same style property is specified in more than one referenced
-style 
-set,
-then the last referenced style
-set
-applies, where the order of application starts from
-the affected element and proceeds to referenced style
-sets,
-and, in turn, to subsequent, recursively
-referenced style
-sets.</p>
-<p>A loop in a sequence of chained style references must be considered an error.</p>
-<p>The use of referential styling is restricted to making
-reference to <el>style</el> element descendants of a <el>styling</el>
-element. It is considered an error to reference a <el>style</el>
-element that is a descendant of a <el>layout</el> element.</p>
-<note role="explanation">
-<p>The use of chained referential styling encourages the grouping of style specifications
-into general and specific sets, which further aids in style specification reuse.</p>
-</note>
-<note role="explanation">
-<p>A single content element may be associated with style properties by a hybrid mixture of
-inline, referential styling, and chained referential styling, in which case inline styling is
-given priority as described above by <specref ref="semantics-style-association-inline"/>.</p>
-</note>
-<table id="style-association-example-3" role="example">
-<caption>Example &ndash; Chained Referential Styling</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;style <phrase role="strong">xml:id="s1"</phrase> tts:color="white" tts:fontFamily="monospaceSerif"/&gt;
-&lt;style <phrase role="strong">xml:id="s2"</phrase> <phrase role="strong">style="s1"</phrase> tts:color="yellow"/&gt;
-...
-&lt;p <phrase role="strong">style="s1"</phrase>&gt;White Monospace&lt;/p&gt;
-&lt;p <phrase role="strong">style="s2"</phrase>&gt;Yellow Monospace&lt;/p&gt;
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-</div4>
-<div4 id="semantics-style-association-nested">
-<head>Nested Styling</head>
-<p>Style properties may be expressed in an nested manner by direct specification of one or
-more <el>style</el> element children of the affected element.
-When expressed in this manner, the association of style information
-is referred to as <emph>nested styling</emph>.</p>
-<p>Style properties associated by nested styling are afforded a lower priority than inline
-styling but with higher priority than referential styling.</p>
-<table id="style-association-example-4" role="example">
-<caption>Example &ndash; Nested Styling</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;region xml:id="r1"&gt;
-  <phrase role="strong">&lt;style tts:extent="128px 66px"/&gt;</phrase>
-  <phrase role="strong">&lt;style tts:origin="0px 0px"/&gt;</phrase>
-  <phrase role="strong">&lt;style tts:displayAlign="center"/&gt;</phrase>
-&lt;/region&gt;
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<note role="clarification">
-<p>In this version of this specification, nested styling applies only
-to the <el>region</el> element.</p>
-</note>
-</div4>
-</div3>
-<div3 id="semantics-style-inheritance">
-<head>Style Inheritance</head>
-<p>Style inheritance is a sub-process of <specref
-ref="semantics-style-resolution-processing"/> used to determine the
-specified style set of each content and
-layout element.</p>
-<p>Styles are further propagated to content matter
-using:
-</p>
-<ulist>
-<item><p><loc href="#semantics-style-inheritance-content">content style inheritance</loc></p></item>
-<item><p><loc href="#semantics-style-inheritance-content">region style inheritance</loc></p></item>
-</ulist>
-<p>For the purpose of determining inherited styles, the element hierarchy of
-an intermediate synchronic document form of a TTML document instance must be used, where
-such intermediate forms are defined by <specref ref="semantics-region-layout-step-1"/>.</p>
-<note role="explanation">
-<p>The intermediate synchronic document form is utilized rather than
-the original form in order to facilitate region inheritance
-processing.</p>
-</note>
-<div4 id="semantics-style-inheritance-content">
-<head>Content Style Inheritance</head>
-<p>Style properties are inherited from ancestor content elements
-within an intermediate synchronic document
-if a style property is not associated with a content element (or
-an anonymous span) and the style property is designated as
-inheritable.</p>
-<p>If a style property is determined to require inheritance, then the inherited value must
-be the value of the same named style property in the computed
-style set of the
-element's immediate ancestor element
-within the applicable intermediate synchronic document.</p>
-<table id="style-inheritance-example-2" role="example">
-<caption>Example &ndash; Content Style Inheritance</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;p <phrase role="strong">tts:fontFamily="monospaceSansSerif"</phrase>&gt;
-  &lt;span tts:color="yellow"&gt;Yellow Monospace&lt;/span&gt;
-&lt;/p&gt;
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<note role="explanation">
-<p>In the above example, the <el>span</el> element that encloses the character items
-<code>Yellow Monospace</code> is not associated with a <att>tts:fontFamily</att> style
-property and this property is inheritable; therefore, the value of the
-<att>tts:fontFamily</att> style
-is inherited from the computed style
-set of the ancestor <el>p</el> element,
-and is added to the
-specified
-style
-set of the <el>span</el> element.</p>
-</note>
-</div4>
-<div4 id="semantics-style-inheritance-region">
-<head>Region Style Inheritance</head>
-<p>Style properties are inherited from a region element in the following case:</p>
-<olist>
-<item><p>if a style property <emph>P</emph> is not associated with
-a content
-element or an anonymous span <emph>E</emph> and the style
-property is designated as inheritable, and</p></item> <item><p>if that
-style property <emph>P</emph> is in the computed style
-set of region
-<emph>R</emph>,
-and</p></item>
-<item><p>if that element <emph>E</emph> is flowed into (presented within) region
-<emph>R</emph>.</p></item>
-</olist>
-<table id="style-inheritance-example-3" role="example">
-<caption>Example &ndash; Region Style Inheritance</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;region <phrase role="strong">xml:id="r1"</phrase>&gt;
-&nbsp;&nbsp;&lt;style tts:color="yellow"/&gt;
-&nbsp;&nbsp;&lt;style tts:fontFamily="monospaceSerif"/&gt;
-&lt;/region&gt;
-...
-&lt;p <phrase role="strong">region="r1"</phrase>&gt;Yellow Monospace&lt;/p&gt;
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<note role="explanation">
-<p>In the above example, the anonymous span that encloses the character
-items <code>Yellow Monospace</code> effectively inherits the <att>tts:color</att>
-and <att>tts:fontFamily</att> styles specified on the <el>region</el>
-element into which the <el>p</el> element is flowed (presented).</p>
-</note>
-</div4>
-</div3>
-<div3 id="semantics-style-resolution-value-categories">
-<head>Style Resolution Value Categories</head>
-<p>During style resolution, layout, and presentation processing,
-three categories of style property values are distinguished as
-follows:</p>
-<ulist>
-<item><p><loc href="#semantics-style-resolved-value-category-specified">specified values</loc></p></item>
-<item><p><loc href="#semantics-style-resolved-value-category-computed">computed values</loc></p></item>
-<item><p><loc href="#semantics-style-resolved-value-category-actual">actual values</loc></p></item>
-</ulist>
-<div4 id="semantics-style-resolved-value-category-specified">
-<head>Specified Values</head>
-<p>Values of style properties that are associated with or inherited
-by an element or anonymous span are referred to as <emph>specified values</emph>. The
-set of all specified style properties of a given element is referred to
-as the <emph>specified style set</emph> of that element.</p>
-</div4>
-<div4 id="semantics-style-resolved-value-category-computed">
-<head>Computed Values</head>
-<p>When style properties are specified using relative value expressions,
-such as a named color, a relative unit (e.g., cell), or a percentage, then
-they need to be further resolved into absolute units, such as an RGB triple,
-pixels, etc.</p>
-<p>During the style resolution process, all specified style values are
-reinterpreted (or recalculated) in absolute terms, and then recorded as
-<emph>computed values</emph>. The
-set of all computed style properties of a given element is referred to
-as the <emph>computed style set</emph> of that element.</p>
-<p>When a style value is inherited, either explicitly or implicitly, it
-is the computed value of the style that is inherited from an ancestor
-element. This is required since the resolution of certain relative units,
-such as percentage, require evaluating the expression in the immediate
-(local) context of reference, and not in a distant (remote) context of
-reference where the related (resolving) expression is not available.</p>
-</div4>
-<div4 id="semantics-style-resolved-value-category-actual">
-<head>Actual Values</head>
-<p>During the actual presentation process, other transformations occur
-that map some value expressions to concrete, physical values. For example,
-the colors of computed style values are further subjected to closest color
-approximation and gamma correction
-during the display process. In addition, length value expressions that use
-pixels in computed style values are considered to express logical rather than
-physical (device) pixels. Consequently, these logical pixels are subject to
-being further transformed or mapped to physical (device) pixels during
-presentation.</p>
-<p>The final values that result from the logical to device mapping
-process are referred to as <emph>actual values</emph>.  The set of all
-actual style properties of a given element is referred to as the
-<emph>actual style set</emph> of that element.</p>
-<note role="elaboration">
-<p>More than one set of actual values may be produced during the
-process of presentation. For example, a TTML presentation processor
-device may output an RGBA component video signal which is then
-further transformed by an NTSC or PAL television to produce a final
-image. In this case, both color and dimensions may further be modified
-prior to presentation.</p>
-</note>
-<note role="explanation">
-<p>In general, a TTML presentation processor will not have access
-to actual style set values; as a consequence, no further use or reference
-to actual values is made below when formally describing the style
-resolution process.</p>
-</note>
-</div4>
-</div3>
-<div3 id="semantics-style-resolution-processing">
-<head>Style Resolution Processing</head>
-<p>The process of style resolution is defined herein as the procedure
-(and results thereof) for resolving (determining) the computed values
-of all style properties that apply to content and layout elements:</p>
-<ulist>
-<item><p><specref ref="semantics-style-resolution-processing-definitions"/></p></item>
-<item><p><specref ref="semantics-style-resolution-processing-sss"/></p></item>
-<item><p><specref ref="semantics-style-resolution-processing-css"/></p></item>
-<item><p><specref ref="semantics-style-resolution-process-overall"/></p></item>
-</ulist>
-<p>The process described here forms an integral sub-process of
-<specref ref="semantics-region-layout"/>.</p>
-<div4 id="semantics-style-resolution-processing-definitions">
-<head>Conceptual Definitions</head>
-<p>For the purpose of interpreting the style resolution processing
-model specified below, the following conceptual definitions apply:</p>
-<glist>
-<gitem>
-<label>[style property]</label>
-<def>
-<p>a style property, <emph>P</emph>, is considered to consist of a
-tuple <code>[name, value]</code>, where the name of the
-property is a tuple <code>[namespace value,
-unqualified name]</code> and the value of the property is a
-tuple <code>[category, type, value expression]</code></p>
-<table id="conceptual-definition-example-style-property" role="example">
-<caption>Example &ndash; conceptual style property</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-[
-  ["http://www.w3.org/ns/ttml#styling", "color"],
-  ["specified", <emph>color</emph>, "red"]
-]
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p/>
-</def>
-</gitem>
-<gitem>
-<label>[style (property) set]</label>
-<def>
-<p>a style (property) set consists of an unordered collection of style
-properties, where no two style properties within the set have an
-identical name, where by "identical name" is meant equality of
-namespace value of name tuple and unqualified name of name tuple;</p>
-<p>in a specified style (property) set, the category of each style
-property is "specified"; a specified style (property) set of an
-element <emph>E</emph> is referred to as <emph>SSS(E)</emph>;</p>
-<table id="conceptual-definition-example-specified-style-set" role="example">
-<caption>Example &ndash; conceptual (specified) style (property) set</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-{
-  [
-    ["http://www.w3.org/ns/ttml#styling", "backgroundColor"],
-    ["specified", <emph>color</emph>, 0x00FF00 ]
-  ],
-  [
-    ["http://www.w3.org/ns/ttml#styling", "color"],
-    ["specified", <emph>color</emph>, "red" ]
-  ],
-  [
-    ["http://www.w3.org/ns/ttml#styling", "fontSize"],
-    ["specified", <emph>length</emph>, "1c" ]
-  ],
-  [
-    ["http://www.w3.org/ns/ttml#styling", "lineHeight"],
-    ["specified", <emph>length</emph>, "117%" ]
-  ]
-}
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p>in a computed style (property) set, the category of each style
-property is either "specified" or "computed"; a computed style (property) set of an element
-<emph>E</emph> is referred to as <emph>CSS(E)</emph>;</p>
-<table id="conceptual-definition-example-computed-style-set" role="example">
-<caption>Example &ndash; conceptual (computed) style (property) set</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-{
-  [
-    ["http://www.w3.org/ns/ttml#styling", "backgroundColor"],
-    ["specified", <emph>color</emph>, 0x00FF00 ]
-  ],
-  [
-    ["http://www.w3.org/ns/ttml#styling", "color"],
-    ["computed", <emph>color</emph>, 0xFF0000 ]
-  ],
-  [
-    ["http://www.w3.org/ns/ttml#styling", "fontSize"],
-    ["computed", <emph>length</emph>, "24px" ]
-  ],
-  [
-    ["http://www.w3.org/ns/ttml#styling", "lineHeight"],
-    ["computed", <emph>length</emph>, "28px" ]
-  ]
-}
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p/>
-</def>
-</gitem>
-<gitem>
-<label>[style (property) merging]</label>
-<def>
-<p>a style property <emph>P<sub>new</sub></emph> is merged into a
-style (property) set, <emph>SS</emph>, as follows: if a style property
-<emph>P<sub>old</sub></emph> is already present in <emph>SS</emph>
-where the name of <emph>P<sub>new</sub></emph> is identical to the
-name of <emph>P<sub>old</sub></emph>, then replace
-<emph>P<sub>old</sub></emph> in <emph>SS</emph> with
-<emph>P<sub>new</sub></emph>; otherwise, add
-<emph>P<sub>new</sub></emph> to <emph>SS</emph>;</p>
-</def>
-</gitem>
-<gitem>
-<label>[style (property) set merging]</label>
-<def>
-<p>a style (property) set <emph>SS<sub>new</sub></emph> is merged into
-an existing style (property) set <emph>SS<sub>old</sub></emph> as
-follows: for each style property <emph>P<sub>new</sub></emph> in
-<emph>SS<sub>new</sub></emph>, merge <emph>P<sub>new</sub></emph> into
-<emph>SS<sub>old</sub></emph>;</p>
-</def>
-</gitem>
-</glist>
-</div4>
-<div4 id="semantics-style-resolution-processing-sss">
-<head>Specified Style Set Processing</head>
-<p>The specified style set <emph>SSS</emph> of an element or
-anonymous span <emph>E</emph>,
-<emph>SSS(E)</emph>, is determined according to the following ordered
-rules:</p>
-<olist>
-<item><p><phrase role="strong">[initialization]</phrase> initialize
-the specified style set <emph>SSS</emph> of <emph>E</emph> to the
-empty set;</p></item>
-<item><p><phrase role="strong">[referential and chained referential
-styling]</phrase> for each <el>style</el> element <emph>S<sub>REF</sub></emph>
-referenced by a <att>style</att> attribute specified on
-<emph>E</emph>, and in the order specified in the <att>style</att>
-attribute, then, if <emph>S<sub>REF</sub></emph> is a descendant
-of a <el>styling</el> element,
-merge the specified style set of
-<emph>S<sub>REF</sub></emph>, <emph>SSS(S<sub>REF</sub>)</emph>, into
-the specified style set of <emph>E</emph>,
-<emph>SSS(E)</emph>;</p></item>
-<item><p><phrase role="strong">[nested styling]</phrase> for each
-nested <el>style</el> element child <emph>S<sub>NEST</sub></emph> of
-<emph>E</emph>, and in the specified order of child elements, merge
-the specified style set of <emph>S<sub>NEST</sub></emph>,
-<emph>SSS(S<sub>NEST</sub>)</emph>, into the specified style set of
-<emph>E</emph>, <emph>SSS(E)</emph>;</p></item>
-<item><p><phrase role="strong">[inline styling]</phrase> for each
-style property <emph>P</emph> expressed as a specified styling
-attribute of <emph>E</emph>,
-merge <emph>P</emph> into the specified style
-set of <emph>E</emph>, <emph>SSS(E)</emph>;</p></item>
-<item>
-<p><phrase role="strong">[implicit inheritance]</phrase> if the
-element type of <emph>E</emph> is not the styling element type
-<el>style</el>, then for each inheritable style property
-<emph>P<sub>INH</sub></emph> in the set of style properties defined
-above in <specref ref="styling-attribute-vocabulary"/>, perform the
-following ordered sub-steps:</p>
-<olist>
-<item><p>if <emph>P<sub>INH</sub></emph> is present in the specified
-style set of <emph>E</emph>, <emph>SSS(E)</emph>, then continue to the
-next inheritable style property;</p></item>
-<item><p>if the element type of <emph>E</emph> is the layout element
-type <el>region</el>, then set <emph>P&prime;</emph> to the initial value of
-property <emph>P</emph>, where the initial value of a property is
-determined according to the specific property definition found above
-in <specref ref="styling-attribute-vocabulary"/>;</p></item>
-<item><p>if the element type of <emph>E</emph> is a content element
-type or anonymous span, then set <emph>P&prime;</emph> to the result of
-looking up the value of <emph>P</emph> in the computed style set of
-the immediate ancestor element of <emph>E</emph>, i.e.,
-<emph>CSS(PARENT(E))</emph>;</p></item>
-<item><p>if the value of <emph>P&prime;</emph> is not undefined, then merge
-<emph>P&prime;</emph> into the specified style set of <emph>E</emph>,
-<emph>SSS(E)</emph>.</p></item>
-</olist>
-</item>
-</olist>
-</div4>
-<div4 id="semantics-style-resolution-processing-css">
-<head>Computed Style Set Processing</head>
-<p>The computed style set <emph>CSS</emph> of an element or
-anonymous span <emph>E</emph>,
-<emph>CSS(E)</emph>, is determined according to the following ordered
-rules:</p>
-<olist>
-<item><p><phrase role="strong">[resolve specified styles]</phrase>
-determine (obtain) the specified style set <emph>SSS</emph> of
-<emph>E</emph>, namely, <emph>SSS(E)</emph>, in accordance with
-<specref ref="semantics-style-resolution-processing-sss"/>;</p>
-</item>
-<item><p><phrase role="strong">[initialization]</phrase>
-initialize <emph>CSS(E)</emph> to a (deep) copy of
-<emph>SSS(E)</emph>;</p></item>
-<item><p><phrase role="strong">[filter]</phrase> if
-<emph>E</emph> is a <el>style</el> element, then return
-<emph>CSS(E)</emph> as the resulting computed style set without
-further resolution; otherwise, continue with the next rule;</p></item>
-<item>
-<p><phrase role="strong">[relative value resolution]</phrase> for each
-style property <emph>P</emph> in <emph>CSS(E)</emph>, where the value
-type of <emph>P</emph> is relative, perform the following ordered
-sub-steps:</p>
-<olist>
-<item><p>replace the relative value of <emph>P</emph> with an
-equivalent, non-relative (computed) value;</p></item>
-<item><p>set the category of <emph>P</emph> to "computed";</p></item>
-</olist>
-</item>
-</olist>
-<note role="explanation">
-<p>As a result of the filtering rule above, the computed style set of
-a <el>style</el> element includes only specified values, in which case
-relative value expressions remain relative; consequently, the
-resolution of relative value expressions (that may be assigned by
-means of referential style association) always takes place in the
-context of a layout or content element which has a presentation
-context, and not in the non-presentation, declaration context
-of a referentiable <el>style</el> element.</p>
-</note>
-</div4>
-<div4 id="semantics-style-resolution-process-overall">
-<head>Style Resolution Process</head>
-<p>The top-level style resolution process is defined as follows: using
-a preorder traversal of each element and anonymous span,
-<emph>E</emph>, of an intermediate synchronic document,
-<emph>DOC<sub>inter</sub></emph>, perform the following ordered
-sub-steps:</p>
-<olist>
-<item><p><phrase role="strong">[filter]</phrase> if the element type
-of <emph>E</emph> is not the styling element type <el>style</el>, is
-not the layout element type <el>region</el>, and is not one of the
-content element types <el>body</el>, <el>div</el>, <el>p</el>,
-<el>span</el>, <el>br</el>, or anonymous span, then continue to the
-next element in the preorder traversal;</p></item>
-<item><p> <phrase role="strong">[resolve computed styles]</phrase>
-determine (obtain) the computed style set <emph>CSS</emph> of
-<emph>E</emph>, namely, <emph>CSS(E)</emph>, in accordance with
-<specref ref="semantics-style-resolution-processing-css"/>.</p></item>
-</olist>
-</div4>
-</div3>
-</div2>
-</div1>
-<div1 id="layout">
-<head>Layout</head>
-<p>This section specifies the <emph>layout</emph> matter of the core
-vocabulary catalog, where
-layout is to be understood as a separable layer of information that applies to
-content and that denotes authorial intentions about the presentation of
-that content.</p>
-<note role="elaboration">
-<p>The two layers of layout and style matter are considered to be independently
-separable. Layout matter specifies one or more spaces or areas into
-which content is intended to be presented, while style matter specifies the manner in
-which presentation occurs within the layout.</p>
-<p>In certain cases, a content author may choose to embed (inline) style matter directly
-into layout or content matter. In such cases, an alternative 
-exists &ndash; use of referential styling &ndash;
-in which the style
-matter is not embedded (inlined).</p>
-</note>
-<div2 id="layout-element-vocabulary">
-<head>Layout Element Vocabulary</head>
-<p>The following elements specify the structure and principal layout aspects of a
-document instance:</p>
-<ulist>
-<item><p><specref ref="layout-vocabulary-layout"/></p></item>
-<item><p><specref ref="layout-vocabulary-region"/></p></item>
-</ulist>
-<div3 id="layout-vocabulary-layout">
-<head>layout</head>
-<p>The <el>layout</el> element is a container element used to group
-layout matter, including metadata that applies to layout matter.</p>
-<p>The <el>layout</el> element accepts as its children zero or more
-elements in the <code>Metadata.class</code> element group, followed by
-zero or more <el>region</el> elements.</p>
-<table id="elt-syntax-layout" role="syntax">
-<caption>XML Representation &ndash; Element Information Item: layout</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;layout
-  <loc href="#content-attribute-id">xml:id</loc> = ID
-  <loc href="#content-attribute-lang">xml:lang</loc> = string
-  <loc href="#content-attribute-space">xml:space</loc> = (<emph>default</emph>|<emph>preserve</emph>)
-  {<emph>any attribute not in default or any TT namespace</emph>}&gt;
-  <emph>Content:</emph> <loc href="#element-vocab-group-table">Metadata.class</loc>*, <loc href="#layout-vocabulary-region">region</loc>*
-&lt;/layout&gt;
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p>To the extent that time semantics apply to the content of the
-<el>layout</el> element, the implied time interval of this element is
-defined to be coterminous with the external time interval.</p>
-</div3>
-<div3 id="layout-vocabulary-region">
-<head>region</head>
-<p>The <el>region</el> element is used to define a space or area into which content is
-to be flowed for the purpose of presentation.</p>
-<p>In addition, and in accordance with
-<specref ref="semantics-style-inheritance-region"/>, 
-the <el>region</el> element may be used to specify inheritable style properties to be
-inherited by content that is flowed into it.</p>
-<p>The <el>region</el> element accepts as its children zero or more
-elements in the <code>Metadata.class</code> element group,
-followed by zero or more
-elements in the <code>Animation.class</code> element group,
-followed by
-zero or more <el>style</el> elements.</p>
-<p>Any metadata specified by children in the <code>Metadata.class</code>
-element group applies semantically to the <el>region</el> element and its descendants as a whole.
-Any animation elements specified by children in the <code>Animation.class</code>
-element group apply semantically to the <el>region</el> element.
-Any <el>style</el> child element must be considered a local style
-definition that applies only to the containing <el>region</el>
-element, i.e., does not apply for resolving referential styling.</p>
-<table id="elt-syntax-region" role="syntax">
-<caption>XML Representation &ndash; Element Information Item: region</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;region
-  <loc href="#timing-attribute-begin">begin</loc> = <loc href="#timing-value-timeExpression">&lt;timeExpression&gt;</loc>
-  <loc href="#timing-attribute-dur">dur</loc> = <loc href="#timing-value-timeExpression">&lt;timeExpression&gt;</loc>
-  <loc href="#timing-attribute-end">end</loc> = <loc href="#timing-value-timeExpression">&lt;timeExpression&gt;</loc>
-  <loc href="#style-attribute-style">style</loc> = IDREFS
-  <loc href="#timing-attribute-timeContainer">timeContainer</loc> = (<emph>par</emph>|<emph>seq</emph>)
-  <loc href="#metadata-attribute-role">ttm:role</loc> = string
-  <loc href="#content-attribute-id">xml:id</loc> = ID
-  <loc href="#content-attribute-lang">xml:lang</loc> = string
-  <loc href="#content-attribute-space">xml:space</loc> = (<emph>default</emph>|<emph>preserve</emph>)
-  {<emph>any attribute in TT Style namespace</emph>}
-  {<emph>any attribute not in default or any TT namespace</emph>}&gt;
-  <emph>Content:</emph> <loc href="#element-vocab-group-table">Metadata.class</loc>*, <loc href="#element-vocab-group-table">Animation.class</loc>*, <loc href="#styling-vocabulary-style">style</loc>*
-&lt;/region&gt;
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p>If <att>begin</att> and (or) <att>end</att> attributes are specified on a
-<el>region</el> element, then they specify the beginning and (or) ending points
-of a time interval during which the region is eligible for activation and with
-respect to which animation child elements of the region are timed.
-If specified, these begin and end points are relative to the time
-interval of the nearest ancestor element associated with a time
-interval, irregardless of whether that interval is explicit or implied.</p>
-<p>The nearest ancestor element of a <el>region</el> element that is associated
-with a time interval is the document instance's root <el>tt</el> element.</p>
-<p>If a <att>dur</att> attribute is specified on the <el>region</el> element, then it
-specifies the simple duration of the region.</p>
-<p>For the purpose of determining the semantics of presentation processing, a
-region that is temporally inactive must not produce any visible marks when
-presented on a visual medium.</p>
-<note role="motivation">
-<p>A <el>region</el> element may be associated with a time interval for two
-purposes: (1) in order to temporally bound the presentation of the region and
-its content, and (2) to provide a temporal context in which animations of region
-styles may be effected.</p>
-<p>For example, an author may wish a region that is otherwise empty, but
-may have a visible background color to be presented starting at some time and
-continuing over the region's duration.  The simple duration of the region serves
-additionally to scope the presentation effects of content that is targeted to the
-region. An author may also wish to move a region within the root container
-extent or change a region's background color by means of animation effects. In
-both of these cases, it is necessary to posit an active time interval for a
-region.</p>
-</note>
-<p>If no <att>timeContainer</att> attribute is specified on
-a <el>region</el> element, then it must be interpreted as having
-<emph>parallel</emph> time containment semantics.</p>
-<p>If a <loc
-href="#metadata-attribute-role"><att>ttm:role</att></loc> attribute is
-specified on a <el>region</el> element, then it must adhere to the
-value syntax defined by <specref
-ref="metadata-attribute-role-syntax"/>, and where the role(s) identified
-by this attribute expresses the semantic role(s) of the region
-independently from the semantic role(s) of any content targeted to
-(associated with) the region.</p>
-</div3>
-</div2>
-<div2 id="layout-attribute-vocabulary">
-<head>Layout Attribute Vocabulary</head>
-<p>This section defines the <specref ref="layout-attribute-region"/> attribute used with content elements.</p>
-<div3 id="layout-attribute-region">
-<head>region</head>
-<p>The <att>region</att> attribute is used to reference a <el>region</el>
-element which defines a space or area into which a content element is intended to be flowed.</p>
-<p>The <att>region</att> attribute may be specified by an instance of the following
-element types:</p>
-<ulist>
-<item><p><loc href="#document-structure-vocabulary-body"><el>body</el></loc></p></item>
-<item><p><loc href="#content-vocabulary-div"><el>div</el></loc></p></item>
-<item><p><loc href="#content-vocabulary-p"><el>p</el></loc></p></item>
-<item><p><loc href="#content-vocabulary-span"><el>span</el></loc></p></item>
-</ulist>
-<note role="seealso">
-<p>See <specref ref="semantics-region-layout"/> below for further information on content
-flow in a region.</p>
-</note>
-</div3>
-</div2>
-<div2 id="semantics-region-layout">
-<head>Region Layout and Presentation</head>
-<p>This section defines the semantics of region layout and
-presentation in terms of a standard processing model as
-follows:</p>
-<ulist>
-<item><p><specref ref="semantics-default-region"/></p></item>
-<item><p><specref ref="semantics-region-layout-step-1"/></p></item>
-<item><p><specref ref="semantics-region-layout-step-2"/></p></item>
-<item><p><specref ref="semantics-region-layout-example"/></p></item>
-</ulist>
-<p>Any
-implementation is permitted provided that the externally observable
-results are consistent with the results produced by this model.
-</p>
-<div3 id="semantics-default-region">
-<head>Default Region</head>
-<p>If a TTML document instance does not specify a
-<loc href="#layout-vocabulary-region"><el>region</el></loc> element,
-then a <emph>default region</emph> is implied with the following characteristics:</p>
-<ulist>
-<item>
-<p>the identity of the default region is considered to be anonymous;</p>
-</item>
-<item>
-<p>the extent of the default region is the same as the root container
-region;</p>
-</item>
-<item>
-<p>the temporal interval of the default region is the same as temporal
-interval of the document instance;</p>
-</item>
-</ulist>
-<p>Furthermore, if no <loc
-href="#layout-vocabulary-region"><el>region</el></loc> element was
-specified, then the <loc
-href="#layout-attribute-region"><att>region</att></loc> attribute must
-not be specified on any content element in the document
-instance.</p>
-<p>If a default region is implied for a given document instance, then
-the <loc href="#document-structure-vocabulary-body"><el>body</el></loc> element
-is implicitly targeted to (associated with) the default region.</p>
-<p>When implying a default region, the document instance is to be
-treated as if a <loc
-href="#layout-vocabulary-region"><el>region</el></loc> element and its
-parent <loc href="#layout-vocabulary-layout"><el>layout</el></loc>
-element were specified in a <loc
-href="#document-structure-vocabulary-head"><el>head</el></loc>
-element, and a matching <loc
-href="#layout-attribute-region"><att>region</att></loc> attribute were
-specified on the <loc
-href="#document-structure-vocabulary-body"><el>body</el></loc> element
-as shown in the following example:</p>
-<table id="semantics-default-region-example" role="example">
-<caption>Example &ndash; Implied Default Region</caption>
-<tbody>
-<tr>
-<td>
-<eg>
-&lt;tt xml:lang="" xmlns="http://www.w3.org/ns/ttml"&gt;
-  &lt;head&gt;
-    <phrase role="strong">&lt;layout&gt;
-      &lt;region xml:id="anonymous"/&gt;
-    &lt;/layout&gt;</phrase>
-  &lt;/head&gt;
-  &lt;body <phrase role="strong">region="anonymous"</phrase>/&gt;
-&lt;/tt&gt;
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<note role="explanation">
-<p>In the above example, a default <el>region</el> element and <att>region</att>
-attribute are implied. In addition, a <el>layout</el> container element is implied for
-the implied <el>region</el> element.</p>
-</note>
-</div3>
-<div3 id="semantics-region-layout-step-1">
-<head>Intermediate Synchronic Document Construction</head>
-<p>For the purposes of performing presentation processing, the active time
-duration of a document instance is divided into a sequence of time coordinates where at
-each time coordinate, some element becomes temporally active or inactive,
-then, at each such time coordinate, a document
-instance is mapped from its original, source
-form, <emph>DOC<sub>source</sub></emph>, 
-to an intermediate
-synchronic document form,
-<emph>DOC<sub>inter</sub></emph>, as follows:</p>
-<olist>
-<item>
-<p>for each temporally active region <emph>R</emph>, replicate the
-sub-tree
- of <emph>DOC<sub>source</sub></emph>
-headed by the <el>body</el> element;</p>
-</item>
-<item>
-<p>evaluating this sub-tree in a postorder traversal, prune elements if they
-are not a content element, if they are temporally inactive, if they are empty,
-or if they aren't associated with region <emph>R</emph>;</p>
-</item>
-<item>
-<p>if the pruned sub-tree is non-empty, then reparent it to the <emph>R</emph>
-element;</p>
-</item>
-<item>
-<p>finally, after completing the above steps, prune the original <el>body</el>
-element from the intermediate document, then prune all <att>region</att>,
-<att>begin</att>, <att>end</att>, and <att>dur</att> attributes, which are no
-longer semantically relevant;</p>
-</item>
-</olist>
-<p>A content element is associated with a region according
-to the following ordered rules, where the first rule satisfied
-is used and remaining rules are skipped:</p>
-<olist>
-<item><p>if the element specifies a <loc
-href="#layout-attribute-region"><att>region</att></loc> attribute,
-then the element is associated with the region referenced by that
-attribute;</p></item>
-<item><p>if some ancestor of that element specifies a <loc
-href="#layout-attribute-region"><att>region</att></loc> attribute,
-then the element is associated with the region referenced by the most
-immediate ancestor that specifies this attribute;</p></item>
-<item><p> if the element contains a descendant element that
-specifies a <loc
-href="#layout-attribute-region"><att>region</att></loc> attribute,
-then the element is associated with the region referenced by that
-attribute;</p></item>
-<item><p>if a default region was implied (due to the absence of any
-<loc href="#layout-vocabulary-region"><el>region</el></loc> element),
-then the element is associated with the default region;</p></item>
-<item><p>the element is not associated with any region.</p></item>
-</olist>
-<p>The pseudo-code shown in <specref ref="content-hierarchy-region-mapping"/>
-provides one possible algorithm that implements these processing steps.</p>
-<table id="content-hierarchy-region-mapping" role="example">
-<caption>Example &ndash; Content Hierarchy Region Mapping</caption>
-<tbody>
-<tr>
-<td>
-<eg>
-PREPARE-CONTENT ( D ) := 
-  foreach R in SELECT ( D, "/tt/head/layout/region" )
-    if TEMPORALLY-ACTIVE? ( R )
-      APPEND-CHILDREN ( R, SELECT ( D, "/tt/body" ) )
-      foreach E in POSTORDER-TRAVERSE ( R )
-        if ! CONTENT-ELEMENT? ( E ) or ! TEMPORALLY-ACTIVE? ( E ) or EMPTY? ( E ) or REGION-OF ( E ) != R
-            then PRUNE ( E )
-  PRUNE ( SELECT ( D, "/tt/body" ) )
-  PRUNE ( SELECT ( D, "//*/@region" ) )
-  PRUNE ( SELECT ( D, "//*/@begin" ) )
-  PRUNE ( SELECT ( D, "//*/@end" ) )
-  PRUNE ( SELECT ( D, "//*/@dur" ) )
- 
-REGION-OF ( E ) :=
-  if NULL? ( E )
-    return NULL
-  else if HAS-ATTRIBUTE? ( E, "region" )
-    return VALUE-OF-ATTRIBUTE ( E, "region" )
-  else
-    return REGION-OF ( PARENT-OF ( E ) )
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p>The result of performing the processing described above will be a sequence of
-<emph>N</emph> intermediate  synchronic
-document instances,
-<emph>DOC<sub><phrase>inter<sub>0</sub></phrase></sub></emph> &hellip;
-<emph>DOC<sub><phrase>inter<sub>N&minus;1</sub></phrase></sub></emph>.</p>
-</div3>
-<div3 id="semantics-region-layout-step-2">
-<head>Synchronic Flow Processing</head>
-<p>Subsequent to performing a temporal (synchronic) slice and subsequent
-remapping of regionally selected content hierarchy, the resulting intermediate
-synchronic document is subjected to a flow transformation step that produces 
-a rooted flow object tree represented as 
-an XSL FO document instance as defined by <bibref ref="xsl11"/>,
-and semantically extended by TTML specific style properties that have no XSL
-FO counterpart.</p>
-<note>
-<p>In this section, the use of XSL FO is intended to be conceptual only, employed
-solely for the purpose of defining the normative presentation semantics of
-TTML. An actual implementation of this algorithm is not required to create or process
-XSL FO representations. In particular, it is possible to implement these semantics
-using alternative presentation models, such as Cascading Style Sheets (CSS).</p>
-</note>
-<p>Each intermediate synchronic  document produced by <specref
-ref="semantics-region-layout-step-1"/> is mapped 
-<!-- changed for future CSS compatibility 
-to an XSL FO document instance, <emph>F</emph>, as follows:</p>
--->
-to a styled document <emph>F</emph> consistent with an XSL FO document instance, as follows</p>
-<olist>
-<item>
-<p>perform the following ordered sub-steps to create anonymous spans:</p>
-<olist>
-<item><p>for each significant text node in a content element,
-synthesize an anonymous span to enclose the text node, substituting
-the new anonymous span for the original text node child in its sibling
-and parent hierarchy;</p></item>
-<item><p>for each contiguous sequence of anonymous spans, replace the
-sequence with a single anonymous span which contains a sequence of
-text nodes representing the individual text node children of the
-original sequence of anonymous spans;</p></item>
-<item><p>for each span element whose child is a single anonymous span,
-replace the anonymous span with its sequence of child text
-nodes;</p></item>
-</olist>
-</item>
-<item>
-<p>resolve styles according to <specref
-ref="semantics-style-resolution-process-overall"/>;</p>
-</item>
-<item>
-<p>map the <el>tt</el> element to an <el>fo:root</el> element, populated
-initially with an <el>fo:layout-master-set</el> element that contains a valid
-<el>fo:simple-page-master</el> that, in turn, contains an
-<el>fo:region-body</el> child, where the root container extent expressed on the
-<el>tt</el> element is mapped to <att>page-width</att> and
-<att>page-height</att> attributes on the <el>fo:simple-page-master</el>
-element;</p>
-</item>
-<item>
-<p>map the <el>layout</el> element to an <el>fo:page-sequence</el> element and a
-child <el>fo:flow</el> element that reference the page master and page region
-defined by the simple page master produced above;</p>
-</item>
-<item>
-<p>map each non-empty <el>region</el> element to an <el>fo:block-container</el>
-element with an <att>absolute-position</att> attribute with value
-<code>absolute</code>, and where the region's position and extent are mapped to equivalent
-<att>top</att>, <att>left</att>, <att>width</att>, and <att>height</att>
-attributes;</p>
-</item>
-<item>
-<p>for each <el>body</el>, <el>div</el>, and <el>p</el> element that is not
-associated with a <att>tts:display</att> style property with the value
-<code>none</code>, map the element to a distinct <el>fo:block</el> element,
-populating the style properties of <el>fo:block</el> by using the computed
-style set associated with each original TTML content element;</p>
-</item>
-<item>
-<p>for the resulting <el>fo:block</el> formatting object
-produced in the previous step that corresponds to the <el>body</el>
-element, synthesize and append to the end of its children an empty
-  <el>fo:block</el> with the following attributes:
-<att>space-after.optimum</att>, <att>space-after.maximum</att>, and
-<att>space-after.conditionality</att>, where the value of the former
-two attributes is the height or width of the containing
-<el>fo:block-container</el> element, whichever of these is designated
-as the block progression dimension, and where the value of the last is
-<code>retain</code>;</p>
-</item>
-<item>
-<p>for each <el>span</el> element that is not
-associated with a <att>tts:display</att> style property with the value
-<code>none</code> and for each anonymous
-span that is a child of a <el>p</el> or <el>span</el> element,
-map the element or
-sequence of character items to a distinct <el>fo:inline</el> element,
-populating the style properties of <el>fo:inline</el> by using the computed
-style set associated with each original TTML content element
-or anonymous span;</p>
-</item>
-<item>
-<p>for each <el>br</el> element that is not
-associated with a <att>tts:display</att> style property with the value
-<code>none</code>, map the element to
-a distinct <el>fo:character</el> element having the following
-properties:</p>
-<ulist>
-<item>
-<p><code>character="&amp;#x000A;"</code></p>
-</item>
-<item>
-<p><code>suppress-at-line-break="retain"</code></p>
-</item>
-</ulist>
-</item>
-<item>
-<p>for each TTML style property attribute in some computed
-style set that
-has no counterpart in <bibref ref="xsl11"/>, map that attribute directly through
-to the relevant formatting object produced by the input TTML content element to
-which the style property applies;</p>
-</item>
-<item>
-<p>optionally, synthesize a unique <att>id</att> attribute on each resulting
-formatting object element that relates that element to the input element that
-resulted in that formatting object element;</p>
-</item>
-</olist>
- <!-- old definition
- <p> For each resulting XSL FO document instance
-  <emph>DOC<sub>FO</sub></emph>,
-if processing
-requires presentation on a visual medium, then apply the formatting semantics
-prescribed by <bibref ref="xsl11"/> in order to produce an XSL FO area tree that
-may then be subsequently rendered onto the visual medium.</p>
-<note role="elaboration">
-<p>In the XSL FO area tree produced by formatting
-<emph>DOC<sub>FO</sub></emph>, the <code>page-viewport-area</code>,
-which is generated by <code>fo:page-sequence</code> element by
-reference to the sole generated <code>fo:simple-page-master</code>
-element, corresponds to the <emph>root container region</emph> defined
-above in <specref ref="definitions"/>.</p>
-</note>
-<note>
-<p>Due to the possible presence of TTML style properties
-or style property values in a given DFXP document instance for which
-there is no <bibref ref="xsl11"/> counterpart, the use of a compliant <bibref ref="xsl11"/> formatting processor
-is not necessarily sufficient to satisfy the presentation
-semantics defined by this specification.</p>
-</note>
---> 
-  <p>For each resulting document instance F, if processing requires presentation on a 
-  visual medium, then apply formatting and rendering semantics consistent with that 
-  prescribed by <bibref ref="xsl11"/>.</p>
-<note role="elaboration">
-<p>In an XSL FO area tree produced by formatting <emph>F</emph> using 
-an <bibref ref="xsl11"/> formatting processor, 
-the <code>page-viewport-area</code>,
-which is generated by <code>fo:page-sequence</code> element by
-reference to the sole generated <code>fo:simple-page-master</code>
-element, would correspond to the <emph>root container region</emph> defined
-above in <specref ref="definitions"/>.</p>
-</note>
-<note>
-<p>
-  Due to the possible presence of TTML style properties or style property values
-  in a given TTML document instance for which there is no <bibref ref="xsl11"/> counterpart,
-  Implementors should recognize that it is the layout model of <bibref ref="xsl11"/> that is being referenced
-  by this specification, not the requirement to use a compliant <bibref ref="xsl11"/> formatting processor,
-  since such would not necessarily be sufficient to satisfy the full presentation semantics
-  defined by this specification, and would contain a large number of features not needed to
-  implement the presentation semantics of TTML.</p>
-</note>
-</div3>
-<div3 id="semantics-region-layout-example">
-<head>Elaborated Example (Informative)</head>
-<p>An example of the processing steps described above is elaborated below, starting with <specref
-ref="region-mapping-example-1-s"/>.</p>
-<table id="region-mapping-example-1-s" role="example">
-<caption>Example &ndash; Sample Source Document</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">&dfxp-ex1;</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p>In the above document, the content hierarchy consists of two divisions, each
-containing two paragraphs. This content is targeted (selected into) one of two
-non-overlapping regions that are styled identically except for their position
-and their foreground colors, the latter of which is inherited by and applies to
-the (and, in this case, anonymous) spans reparented into the regions.</p>
-<p>The following, first intermediate document shows the synchronic state at time
-interval [0,1), during which time only division <code>d1</code> is temporally active,
-and where paragraphs <code>p1</code> and <code>p2</code> (and their ancestors)
-are selected into regions <code>r1</code> and <code>r2</code>, respectively.</p>
-<note>
-<p>The intermediate documents shown below are not valid TTML document instances,
-but rather, are representations of possible internal processing states used for
-didactic purposes.</p>
-</note>
-<table id="region-mapping-example-1-i0" role="example">
-<caption>Example &ndash; Intermediate Document &ndash; [0s,1s)</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">&dfxp-ex1-x-0;</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p>
-  <!-- old text 
-  An XSL FO document instance produced by performing flow processing
-  upon the first intermediate document is shown below.
-  -->
-  An XSL FO document instance that would yield rendering consistent with TTML, and 
-  which may be produced by performing flow processing upon the first intermediate 
-  document is illustrated below.
-</p>
-<table id="region-mapping-example-1-f0" role="example">
-<caption>Example &ndash; XSL FO Document &ndash; [0s,1s)</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">&dfxp-ex1-p-0;</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p>The following, second intermediate document shows the synchronic state at
-time interval [1,2), at which time both divisions <code>d1</code> and
-<code>d2</code> are temporally active, and where paragraphs <code>p1</code> and
-<code>p4</code> (and their ancestors) are selected into region <code>r1</code>
-and paragraphs <code>p2</code> and <code>p3</code> (and their ancestors) are
-selected into region <code>r2</code>.</p>
-<table id="region-mapping-example-1-i1" role="example">
-<caption>Example &ndash; Intermediate Document &ndash; [1s,2s)</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">&dfxp-ex1-x-1;</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p>The following, third intermediate document shows the synchronic state at time
-interval [2,3), at which time only division <code>d2</code> is temporally active,
-and where paragraphs <code>p4</code> and <code>p3</code> (and their ancestors)
-are selected into regions <code>r1</code> and <code>r2</code>, respectively.</p>
-<table id="region-mapping-example-1-i2" role="example">
-<caption>Example &ndash; Intermediate Document &ndash; [2s,3s)</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">&dfxp-ex1-x-2;</eg>
-</td>
-</tr>
-</tbody>
-</table>
-</div3>
-</div2>
-<div2 id="semantics-line-layout">
-<head>Line Layout</head>
-  <!--
-<p>The semantics of line layout, including line breaking, defined by 
-<bibref ref="xsl11"/> apply to the performance of the composition and layout of
-lines for presentation processing of a document instance on a visual medium.</p>
--->
-  
-<p>If a profile that applies to a document instance
-requires use of the <loc
-href="#feature-lineBreak-uax14">#lineBreak-uax14</loc> feature
-(i.e., the value attribute for the feature is specified as <code>use</code>), then
-the recommendations defined by <loc
-href="http://www.unicode.org/unicode/reports/tr14/#Algorithm">Line
-Breaking Algorithm</loc> <bibref ref="uax14"/> apply when performing
-line layout on the content of the document instance.</p>
-</div2>
-</div1>
-<div1 id="timing">
-<head>Timing</head>
-<p>This section specifies the <emph>timing</emph> matter of the core
-vocabulary catalog, where
-timing is to be understood as a separable layer of information that applies to
-content and that denotes authorial intentions about the temporal presentation of
-that content.</p>
-<div2 id="timing-element-vocabulary">
-<head>Timing Element Vocabulary</head>
-<p>No timing related element vocabulary is defined for use in the core
-vocabulary catalog.</p>
-</div2>
-<div2 id="timing-attribute-vocabulary">
-<head>Timing Attribute Vocabulary</head>
-<p>This section defines the following basic timing attributes for use with timed elements:</p>
-<ulist>
-<item><p><specref ref="timing-attribute-begin"/></p></item>
-<item><p><specref ref="timing-attribute-end"/></p></item>
-<item><p><specref ref="timing-attribute-dur"/></p></item>
-</ulist>
-<p>In addition, this section defines the <specref
-ref="timing-attribute-timeContainer"/> attribute for use with timed elements
-that serve simultaneously as timing containers.</p>
-<div3 id="timing-attribute-begin">
-<head>begin</head>
-<p>The <att>begin</att> attribute is used to specify the begin
-point of a temporal interval associated with a timed element. If
-specified, the value of a <att>begin</att> attribute must adhere to
-a &lt;timeExpression&gt; specification as defined by <specref
-ref="timing-value-timeExpression"/>.</p>
-<p>The begin point of a temporal interval is included in the
-interval; i.e., the interval is left-wise closed.</p>
-<p>The semantics of the <att>begin</att> attribute are those defined
-by <bibref ref="smil21"/>, &sect; 10.4.1,
-while taking into account any overriding semantics defined by this specification.</p>
-</div3>
-<div3 id="timing-attribute-end">
-<head>end</head>
-<p>The <att>end</att> attribute is used to specify the ending point
-of a temporal interval associated with a timed element. If
-specified, the value of an <att>end</att> attribute must adhere to a
-&lt;timeExpression&gt; specification as defined by <specref
-ref="timing-value-timeExpression"/>.</p>
-<p>The ending point of a temporal interval is not included in the
-interval; i.e., the interval is right-wise open.</p>
-<p>The presentation effects of a non-empty active
-temporal interval include the frame immediately prior to the frame
-(or tick) equal to or immediately following the time specified by the ending
-point, but do not extend into this latter frame (or tick).</p>
-<note role="example">
-<p>For example, if an active interval is [10s,10.33333s), and the
-frame rate is 30 frames per second, then the presentation effects of the interval
-are limited to frames 300 through 309 only (assuming that 0s corresponds
-with frame 0). The same holds if the active interval is specified
-as [300f,310f).</p>
-</note>
-<p>The semantics of the <att>end</att> attribute are those defined
-by <bibref ref="smil21"/>, &sect; 10.4.1,
-while taking into account any overriding semantics defined by this specification.</p>
-</div3>
-<div3 id="timing-attribute-dur">
-<head>dur</head>
-<p>The <att>dur</att> attribute is used to specify the duration of a
-temporal interval associated with a timed element. If specified,
-the value of a <att>dur</att> attribute must adhere to a
-&lt;timeExpression&gt; specification as defined by <specref
-ref="timing-value-timeExpression"/>.</p>
-<note role="clarification">
-<p>When the <code>clock-time</code> form of a &lt;timeExpression&gt; specification
-is used with a <att>dur</att> attribute, it is intended to be interpreted as
-a difference between two implied clock time expressions.</p>
-</note>
-<p>When a TTML document instance specifies the use of the
-<code>smpte</code> time base and <code>discontinuous</code> marker
-mode, the <att>dur</att> attribute must not be specified on any
-element.</p>
-<p>The semantics of the <att>dur</att> attribute are those defined
-by <bibref ref="smil21"/>, &sect; 10.4.1,
-while taking into account any overriding semantics defined by this specification.</p>
-<note role="elaboration">
-<p>In the context of the subset of <bibref ref="smil21"/> semantics supported by
-this specification, the active duration of an element that specifies both
-<att>end</att> and <att>dur</att> attributes is equal to the lesser of the value of
-the <att>dur</att> attribute and the difference between the value of the
-<att>end</att> attribute and the element's begin time.</p>
-</note>
-</div3>
-<div3 id="timing-attribute-timeContainer">
-<head>timeContainer</head>
-<p>The <att>timeContainer</att> attribute is used to specify a local temporal
-context by means of which timed child elements are temporally situated.</p>
-<p>If specified, the value of a <att>timeContainer</att> attribute must be one
-of the following:</p>
-<ulist>
-<item><p><code>par</code></p></item>
-<item><p><code>seq</code></p></item>
-</ulist>
-<p>If the time container semantics of an element instance is <code>par</code>,
-then the temporal intervals of child elements are considered to apply in
-parallel, i.e., simultaneously in time. Furthermore, the specification of
-the time interval of each child element is considered to be relative to the temporal
-interval of the container element instance.</p>
-<p>If the time container semantics of an element instance is <code>seq</code>,
-then the temporal intervals of child elements are considered to apply in
-sequence, i.e., sequentially in time. Furthermore, the specification of
-the time interval of each child element is considered to be relative to the temporal
-interval of its sibling elements, unless it is the first child element, in which case
-it is considered to be relative to the temporal interval of the container
-element instance.</p>
-<p>Each time container is considered to constitute an independent time base, i.e.,
-time coordinate system.</p>
-<p>If a <att>timeContainer</att> attribute is not specified on an element that
-has time container semantics, then <code>par</code> time container semantics must apply.</p>
-<p>Time container semantics applies only to the following element types:</p>
-<ulist>
-<item><p><loc href="#document-structure-vocabulary-body"><el>body</el></loc></p></item>
-<item><p><loc href="#content-vocabulary-div"><el>div</el></loc></p></item>
-<item><p><loc href="#content-vocabulary-p"><el>p</el></loc></p></item>
-<item><p><loc href="#layout-vocabulary-region"><el>region</el></loc></p></item>
-<item><p><loc href="#content-vocabulary-span"><el>span</el></loc></p></item>
-</ulist>
-<p>The semantics of parallel and sequential time
-containment are those defined by <bibref ref="smil21"/>, &sect; 10.4.2,
-while taking into account any overriding semantics defined by this specification.</p>
-</div3>
-</div2>
-<div2 id="timing-time-value-expressions">
-<head>Time Value Expressions</head>
-<p>Timing attribute values include the use of the following expressions:</p>
-<ulist>
-<item><p><specref ref="timing-value-timeExpression"/></p></item>
-</ulist>
-<div3 id="timing-value-timeExpression">
-<head>&lt;timeExpression&gt;</head>
-<p>A &lt;timeExpression&gt; is used to specify a coordinate along
-some time base, where the applicable time base is determined by the
-<att>ttp:timeBase</att> parameter.</p>
-<note role="example">
-<p>See <specref ref="parameter-attribute-timeBase"/>, <specref
-ref="parameter-attribute-frameRate"/>, <specref
-ref="parameter-attribute-subFrameRate"/>, and <specref
-ref="parameter-attribute-tickRate"/> for further information on
-explicit specification of time base, frame rate, sub-frame rate, and
-tick rate.</p>
-</note>
-<table id="timeExpression-syntax" role="syntax">
-<caption>Syntax Representation &ndash; &lt;timeExpression&gt;</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;timeExpression&gt;
-  : clock-time
-  | offset-time
-
-clock-time
-  : hours ":" minutes ":" seconds ( fraction | ":" frames ( "." sub-frames )? )?
-
-offset-time
-  : time-count fraction? metric
-
-hours
-  : <loc href="#style-value-digit">&lt;digit&gt;</loc> <loc href="#style-value-digit">&lt;digit&gt;</loc>
-  | <loc href="#style-value-digit">&lt;digit&gt;</loc> <loc href="#style-value-digit">&lt;digit&gt;</loc> <loc href="#style-value-digit">&lt;digit&gt;</loc>+
-
-minutes | seconds
-  : <loc href="#style-value-digit">&lt;digit&gt;</loc> <loc href="#style-value-digit">&lt;digit&gt;</loc>
-
-frames
-  : <loc href="#style-value-digit">&lt;digit&gt;</loc> <loc href="#style-value-digit">&lt;digit&gt;</loc>
-  | <loc href="#style-value-digit">&lt;digit&gt;</loc> <loc href="#style-value-digit">&lt;digit&gt;</loc> <loc href="#style-value-digit">&lt;digit&gt;</loc>+
-
-sub-frames
-  : <loc href="#style-value-digit">&lt;digit&gt;</loc>+
-
-fraction
-  : "." <loc href="#style-value-digit">&lt;digit&gt;</loc>+
-
-time-count
-  : <loc href="#style-value-digit">&lt;digit&gt;</loc>+
-
-metric
-  : "h"                 // hours
-  | "m"                 // minutes
-  | "s"                 // seconds
-  | "ms"                // milliseconds
-  | "f"                 // frames
-  | "t"                 // ticks
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<!--
-<p>If a &lt;timeExpression&gt; is expressed in terms of an
-<emph>offset-time</emph> and no <emph>metric</emph> term is specified,
-then the default metric specified by a
-<att>ttp:defaultTimeMetric</att> parameter is used. If no
-default metric is specified, then the time count must be interpreted
-as seconds.</p>
--->
-<p>If a &lt;timeExpression&gt; is expressed in terms of a
-<emph>clock-time</emph>, then leading zeroes are used when expressing hours,
-minutes, seconds, and frames less than 10. Minutes are constrained to the range
-[0&hellip;59], while seconds are constrained to [0&hellip;60], where the value 60
-applies only to leap seconds.</p>
-<p>If a &lt;timeExpression&gt; is expressed in terms of a
-<emph>clock-time</emph> and a <emph>frames</emph> term is specified,
-then the value of this term must be constrained to the interval
-[0&hellip;<emph>F-1</emph>], where <emph>F</emph> is the frame rate
-determined by the <att>ttp:frameRate</att> parameter as defined
-by <specref ref="parameter-attribute-frameRate"/>.</p>
-<p>If a &lt;timeExpression&gt; is expressed in terms of a
-<emph>clock-time</emph> and a <emph>sub-frames</emph> term is
-specified, then the value of this term must be constrained to the
-interval [0&hellip;<emph>S-1</emph>], where <emph>S</emph> is the
-sub-frame rate determined by the <att>ttp:subFrameRate</att> parameter as defined by <specref
-ref="parameter-attribute-subFrameRate"/>.</p>
-</div3>
-</div2>
-<div2 id="timing-time-intervals">
-<head>Time Intervals</head>
-<p>The semantics of time containment, durations, and intervals defined by
-<bibref ref="smil21"/> apply to the interpretation of like-named timed elements and timing
-vocabulary defined by this specification, given the following
-constraints:</p>
-<ulist>
-<item>
-<p>The implicit duration of
-
-an anonymous span
-
-is defined as follows: if
-the
-
-anonymous span's
-
-parent time container is a parallel time container, then
-the implicit duration is equivalent to the <code>indefinite</code>
-duration value as defined by <bibref ref="smil21"/>; if the
-
-anonymous span's
-
-parent time container is a sequential time container, then the
-implicit duration is equivalent to zero.</p>
-</item>
-<item>
-<p>The implicit duration of a <el>body</el>, <el>div</el>, <el>p</el>,
-or <el>span</el> element is determined in accordance to (1) whether
-the element is a parallel or sequential time container, and (2) the
-semantics of <bibref ref="smil21"/> as applied to these time
-containers.</p>
-</item>
-<item>
-<p>The implicit duration of the <el>region</el> element is defined to
-be equivalent to the <code>indefinite</code>
-duration value as defined by <bibref ref="smil21"/>.</p>
-</item>
-<item>
-<p>If the governing time mode is <code>media</code> or
-<code>smpte</code> with mode <code>continuous</code>, then time
-expressions must be interpreted as
-equivalent to offset based timing
-in <bibref ref="smil21"/>, namely, as offsets from an implicit
-syncbase.</p>
-</item>
-<item>
-<p>If the governing time mode is <code>smpte</code> with mode
-<code>discontinuous</code>, then time expressions must be interpreted
-as equivalent to marker values produced by an external marker event
-source, in which case all time expressions are equivalent to event
-based timing in <bibref ref="smil21"/>.</p>
-</item>
-<item>
-<p>If the governing time mode is <code>clock</code>, then time
-expressions must be interpreted as equivalent to wallclock time
-expressions in <bibref ref="smil21"/>, where the applicable wallclock
-used is determined by the clock mode parameter.</p>
-</item>
-</ulist>
-</div2>
-</div1>
-<div1 id="animation">
-<head>Animation</head>
-<p>This section specifies the <emph>animation</emph> matter of the
-core vocabulary catalog, where
-animation is to be understood as a separable layer of information that combines
-timing and styling in order to denote authorial intention about (temporally) dynamic
-styling of content.</p>
-<div2 id="animation-element-vocabulary">
-<head>Animation Element Vocabulary</head>
-<p>The following elements specify the structure and principal animation aspects of a
-document instance:</p>
-<ulist>
-<item><p><specref ref="animation-vocabulary-set"/></p></item>
-</ulist>
-<div3 id="animation-vocabulary-set">
-<head>set</head>
-<p>The <el>set</el> element is used as a child element of a content
-element or a <el>region</el> element
-in order to express a discrete change of some style parameter value
-that applies over some time interval.</p>
-<p>The <el>set</el> element accepts as its children zero or more
-elements in the <code>Metadata.class</code> element group.</p>
-<table id="elt-syntax-set" role="syntax">
-<caption>XML Representation &ndash; Element Information Item: set</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;set
-  <loc href="#timing-attribute-begin">begin</loc> = <loc href="#timing-value-timeExpression">&lt;timeExpression&gt;</loc>
-  <loc href="#timing-attribute-dur">dur</loc> = <loc href="#timing-value-timeExpression">&lt;timeExpression&gt;</loc>
-  <loc href="#timing-attribute-end">end</loc> = <loc href="#timing-value-timeExpression">&lt;timeExpression&gt;</loc>
-  <loc href="#content-attribute-id">xml:id</loc> = ID
-  <loc href="#content-attribute-lang">xml:lang</loc> = string
-  <loc href="#content-attribute-space">xml:space</loc> = (<emph>default</emph>|<emph>preserve</emph>)
-  {<emph>a single attribute in TT Style namespace</emph>}
-  {<emph>any attribute not in default or any TT namespace</emph>}&gt;
-  <emph>Content:</emph> <loc href="#element-vocab-group-table">Metadata.class</loc>*
-&lt;/set&gt;
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<note role="example">
-<p>The use of multiple <el>set</el> element children may be used to effect fade and
-position transitions.</p>
-</note>
-<p>An example of using the <el>set</el> element to animate content
-styling is illustrated below:</p>
-<table id="animation-vocabulary-set-example-1" role="example">
-<caption>Example Fragment &ndash; Content Style Animation</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-...
-&lt;p dur="5s" tts:color="yellow"&gt;
-<phrase role="strong">&lt;set begin="1s" dur="1s" tts:color="red"/&gt;</phrase>
-<phrase role="strong">&lt;set begin="2s" dur="1s" tts:color="green"/&gt;</phrase>
-<phrase role="strong">&lt;set begin="3s" dur="1s" tts:color="red"/&gt;</phrase>
-Text with Flashing Colors!
-&lt;/p&gt;
-...
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<note role="explanation">
-<p>In the above example, the foreground color of the content "Text
-with Flashing Colors" is animated from yellow, to red, to green, to
-red, then back to yellow over a 5 second period.</p>
-</note>
-
-<p>An example of using the <el>set</el> element to animate region
-styling is illustrated below:</p>
-<table id="animation-vocabulary-set-example-2" role="example">
-<caption>Example Fragment &ndash; Region Style Animation</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;tt xml:lang="" xmlns="http://www.w3.org/ns/ttml"
-    xmlns:ttp="http://www.w3.org/ns/ttml#parameter"
-    xmlns:tts="http://www.w3.org/ns/ttml#styling"
-    ttp:cellResolution="40 16"&gt;
-    &lt;head&gt;
-      &lt;layout&gt;
-	&lt;region xml:id="r1" timeContainer="seq"&gt;
-	  <phrase role="strong">&lt;set dur="10s" tts:origin=" 8c 14c"/&gt;</phrase>
-	  <phrase role="strong">&lt;set dur="2s"  tts:origin=" 2c  2c"/&gt;</phrase>
-	  <phrase role="strong">&lt;set dur="3s"  tts:origin=" 8c 14c"/&gt;</phrase>
-	  <phrase role="strong">&lt;set dur="2s"  tts:origin="14c  4c"/&gt;</phrase>
-	  <phrase role="strong">&lt;set dur="10s" tts:origin=" 8c 14c"/&gt;</phrase>
-	  &lt;style tts:extent="24c 2c"/&gt;
-	&lt;/region&gt;
-      &lt;/layout&gt;
-    &lt;/head&gt;
-    &lt;body region="r1"&gt;...&lt;/body&gt;
-&lt;/tt&gt;
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<note role="explanation">
-<p>In the above example, the root container region is divided into a
-cell grid of 40 columns and 16 rows. A region, <code>r1</code>, with
-dimensions of 24 columns and 2 rows is then positioned within the
-root container region, with its position varying over time in order to
-create an effect of moving the region, which may be desirable so as
-to avoid obscuring characters in an underlying video with captions.</p>
-</note>
-<note role="derivation">
-<p>The semantics of the <el>set</el> element
-are based upon that defined by <bibref ref="smil21"/>,
-&sect; 3.6.2.</p>
-</note>
-</div3>
-</div2>
-<div2 id="animation-attribute-vocabulary">
-<head>Animation Attribute Vocabulary</head>
-<p>No animation related attribute vocabulary is defined for use in the
-core vocabulary catalog.</p>
-</div2>
-</div1>
-<div1 id="metadata">
-<head>Metadata</head>
-<p>This section specifies the <emph>metadata</emph> matter of the core
-vocabulary catalog, where
-metadata is to be understood as a separable layer of information that applies to
-parameters, content,
-style, layout, timing, and even metadata itself, where the information
-represented by metadata takes one of two forms: (1) metadata defined by this
-specification for standardized use in a document instance, and (2) arbitrary
-metadata defined outside of the scope of this specification, whose use and
-semantics depend entirely upon an application's use of TTML content.</p>
-<div2 id="metadata-element-vocabulary">
-<head>Metadata Element Vocabulary</head>
-<p>The <specref ref="metadata-vocabulary-metadata"/> element serves as
-a generic container element for grouping metadata information.</p>
-<p>In addition, the following elements, all defined in the TT Metadata Namespace,
-provide standard representations for common metadata that is expected to be commonly
-used in a document instances:
-</p>
-<ulist>
-<item><p><specref ref="metadata-vocabulary-title"/></p></item>
-<item><p><specref ref="metadata-vocabulary-desc"/></p></item>
-<item><p><specref ref="metadata-vocabulary-copyright"/></p></item>
-<item><p><specref ref="metadata-vocabulary-agent"/></p></item>
-<item><p><specref ref="metadata-vocabulary-name"/></p></item>
-<item><p><specref ref="metadata-vocabulary-actor"/></p></item>
-</ulist>
-<div3 id="metadata-vocabulary-metadata">
-<head>metadata</head>
-<p>The <el>metadata</el> element functions as a generic container for metadata
-information.</p>
-<p>Metadata information may be expressed by a <el>metadata</el> element
-in one of two (non-mutually exclusive) manners: (1) by specifying one
-or more metadata attributes on the <el>metadata</el>
-element, and (2) by specifying one
-or more child elements
-in the <el>metadata</el> element
-that express metadata. Both types of metadata
-are referred to in this document as <emph>metadata items</emph>.</p>
-<table id="elt-syntax-metadata" role="syntax">
-<caption>XML Representation &ndash; Element Information Item: metadata</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;metadata
-  <loc href="#content-attribute-id">xml:id</loc> = ID
-  <loc href="#content-attribute-lang">xml:lang</loc> = string
-  <loc href="#content-attribute-space">xml:space</loc> = (<emph>default</emph>|<emph>preserve</emph>)
-  {<emph>any attribute in TT Metadata namespace</emph>}
-  {<emph>any attribute not in default or any TT namespace</emph>}&gt;
-  <emph>Content:</emph> ({<emph>any element in TT Metadata namespace</emph>}|{<emph>any element not in any TT namespace</emph>})*
-&lt;/metadata&gt;
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<note role="explanation">
-<p>The meaning of a specific metadata item must be evaluated in the
-context of where it appears. The core vocabulary catalog permits an
-arbitrary number of <el>metadata</el> element children of any
-content element type except for the
-<el>tt</el> element. See specific element
-vocabulary definitions for any constraints that apply to such
-usage.</p>
-</note>
-<p>The use of document metadata is illustrated by the following example.</p>
-<table id="metadata-vocabulary-metadata-example-1" role="example">
-<caption>Example Fragment &ndash; Document Metadata</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-...
-&lt;head&gt;
-  &lt;metadata xmlns:ttm="http://www.w3.org/ns/ttml#metadata"&gt;
-    &lt;ttm:title&gt;Document Metadata Example&lt;/ttm:title&gt;
-    &lt;ttm:desc&gt;This document employs document metadata.&lt;/ttm:desc&gt;
-  &lt;/metadata&gt;
-&lt;/head&gt;
-...
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p/>
-<p>The use of element metadata is illustrated by the following example.</p>
-<table id="metadata-vocabulary-metadata-example-2" role="example">
-<caption>Example Fragment &ndash; Element Metadata</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-...
-&lt;div&gt;
-  &lt;metadata xmlns:ttm="http://www.w3.org/ns/ttml#metadata"&gt;
-    &lt;ttm:title&gt;Chapter 6 &ndash; Sherlock Holmes Gives a Demonstration&lt;/ttm:title&gt;
-    &lt;ttm:desc&gt;Holmes shows Watson how the murderer entered the window.&lt;/ttm:desc&gt;
-  &lt;/metadata&gt;
-&lt;/div&gt;
-...
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p/>
-
-<p>The use of metadata attribute items is illustrated by the following example.</p>
-<table id="metadata-vocabulary-metadata-example-3" role="example">
-<caption>Example Fragment &ndash; Foreign Metadata Attribute Items</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-...
-&lt;div xmlns:ext="http://foo.bar.example.org/ttaf1#metadata"&gt;
-  &lt;metadata ext:ednote="remove this division prior to publishing"/&gt;
-&lt;/div&gt;
-...
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<note role="explanation">
-<p>In the above example, a global attribute from a foreign (external)
-namespace is used to express a metadata attribute that applies
-semantically to the containing <el>div</el> element. Note that the
-attribute may also be expressed directly on the <el>div</el> element;
-however, in this case the author wishes to segregate certain metadata
-attributes by expressing them indirectly on <el>metadata</el>
-elements.</p>
-</note>
-<p/>
-<p>The use of foreign element metadata is illustrated by the following example.</p>
-<table id="metadata-vocabulary-metadata-example-4" role="example">
-<caption>Example Fragment &ndash; Foreign Element Metadata</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-...
-&lt;metadata
-  xmlns:dc="http://purl.org/dc/elements/1.1/"
-  xmlns:dcterms="http://purl.org/dc/terms/"
-  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"&gt;
-  &lt;dc:title&gt;Foreign Element Metadata Example&lt;/dc:title&gt;
-  &lt;dc:description&gt;Express metadata using elements in foreign namespace.&lt;/dc:description&gt;
-  &lt;dc:format xsi:type="dcterms:IMT"&gt;application/ttml+xml&lt;/dc:format&gt;
-&lt;/metadata&gt;
-...
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<note role="explanation">
-<p>In the above example, a number of elements defined by the Dublin
-Core metadata vocabulary are used to express document level metadata.</p>
-</note>
-<p/>
-</div3>
-<div3 id="metadata-vocabulary-title">
-<head>ttm:title</head>
-<p>The <el>ttm:title</el> element is used to express a human-readable title of
-a specific element instance.</p>
-<table id="elt-syntax-metadata-title" role="syntax">
-<caption>XML Representation &ndash; Element Information Item: ttm:title</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;ttm:title
-  <loc href="#content-attribute-id">xml:id</loc> = ID
-  <loc href="#content-attribute-lang">xml:lang</loc> = string
-  <loc href="#content-attribute-space">xml:space</loc> = (<emph>default</emph>|<emph>preserve</emph>)
-  {<emph>any attribute not in default or any TT namespace</emph>}&gt;
-  <emph>Content:</emph> #PCDATA
-&lt;/ttm:title&gt;
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<note role="elaboration">
-<p>No specific use of the <el>ttm:title</el> element is defined by this specification.</p>
-</note>
-<p>Examples of the <att>ttm:title</att> element are shown above in
-<specref ref="metadata-vocabulary-metadata-example-1"/> and
-<specref ref="metadata-vocabulary-metadata-example-2"/>.</p>
-</div3>
-<div3 id="metadata-vocabulary-desc">
-<head>ttm:desc</head>
-<p>The <el>ttm:desc</el> element is used to express a human-readable description of
-a specific element instance.</p>
-<table id="elt-syntax-metadata-desc" role="syntax">
-<caption>XML Representation &ndash; Element Information Item: ttm:desc</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;ttm:desc
-  <loc href="#content-attribute-id">xml:id</loc> = ID
-  <loc href="#content-attribute-lang">xml:lang</loc> = string
-  <loc href="#content-attribute-space">xml:space</loc> = (<emph>default</emph>|<emph>preserve</emph>)
-  {<emph>any attribute not in default or any TT namespace</emph>}&gt;
-  <emph>Content:</emph> #PCDATA
-&lt;/ttm:desc&gt;
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<note role="elaboration">
-<p>No specific use of the <el>ttm:desc</el> element is defined by this specification.</p>
-</note>
-<p>Examples of the <att>ttm:desc</att> element are shown above in
-<specref ref="metadata-vocabulary-metadata-example-1"/> and
-<specref ref="metadata-vocabulary-metadata-example-2"/>.</p>
-</div3>
-<div3 id="metadata-vocabulary-copyright">
-<head>ttm:copyright</head>
-<p>The <el>ttm:copyright</el> element is used to express a human-readable copyright that
-applies to some scoping level.</p>
-<p>A copyright statement that applies to a document as a whole should appear as a
-child of the <el>head</el> element.</p>
-<table id="elt-syntax-metadata-copyright" role="syntax">
-<caption>XML Representation &ndash; Element Information Item: ttm:copyright</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;ttm:copyright
-  <loc href="#content-attribute-id">xml:id</loc> = ID
-  <loc href="#content-attribute-lang">xml:lang</loc> = string
-  <loc href="#content-attribute-space">xml:space</loc> = (<emph>default</emph>|<emph>preserve</emph>)
-  {<emph>any attribute not in default or any TT namespace</emph>}&gt;
-  <emph>Content:</emph> #PCDATA
-&lt;/ttm:copyright&gt;
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<note role="elaboration">
-<p>No specific use of the <el>ttm:copyright</el> element is defined by this specification.</p>
-</note>
-</div3>
-<div3 id="metadata-vocabulary-agent">
-<head>ttm:agent</head>
-<p>The <el>ttm:agent</el> element is used to define an agent for the purpose of associating
-content information with an agent who is involved in the production or expression of that content.</p>
-<p>The <el>ttm:agent</el> element accepts as its children zero or more <el>ttm:name</el> elements followed by
-zero or one <el>ttm:actor</el> element.</p>
-<p>At least one <el>ttm:name</el> element child should be specified that expresses a name for the
-agent, whether it be the name of a person, character, group, or organization.</p>
-<table id="elt-syntax-metadata-agent" role="syntax">
-<caption>XML Representation &ndash; Element Information Item: ttm:agent</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;ttm:agent
-  <phrase role="reqattr">type</phrase> = (<emph>person</emph>|<emph>character</emph>|<emph>group</emph>|<emph>organization</emph>|<emph>other</emph>)
-  <loc href="#content-attribute-id">xml:id</loc> = ID
-  <loc href="#content-attribute-lang">xml:lang</loc> = string
-  <loc href="#content-attribute-space">xml:space</loc> = (<emph>default</emph>|<emph>preserve</emph>)
-  {<emph>any attribute not in default or any TT namespace</emph>}&gt;
-  <emph>Content:</emph> <loc href="#metadata-vocabulary-name">ttm:name</loc>*, <loc href="#metadata-vocabulary-actor">ttm:actor</loc>?
-&lt;/ttm:agent&gt;
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p>A <att>type</att> attribute must be specified on each <el>ttm:agent</el> element, and,
-if specified, must have one of the following values:</p>
-<ulist>
-<item><p><el>person</el></p></item>
-<item><p><el>character</el></p></item>
-<item><p><el>group</el></p></item>
-<item><p><el>organization</el></p></item>
-<item><p><el>other</el></p></item>
-</ulist>
-<p>If the value of the <att>type</att> attribute is <code>character</code>, then the
-<el>ttm:agent</el> element instance should specify a <el>ttm:actor</el> child that
-specifies the agent that plays the role of the actor.</p>
-<p>A <att>ttm:agent</att> metadata item is considered to be significant only
-when specified as a child of the <el>head</el> element or as a child of a
-<el>metadata</el> element child of the <el>head</el> element.</p>
-<note role="elaboration">
-<p>A <el>ttm:agent</el> element instance is typically referenced using a <att>ttm:agent</att>
-attribute on a content element.</p>
-</note>
-<note role="elaboration">
-<p>If a character agent is played by multiple actors, then multiple character
-agents may be specified (and referenced) wherein different definitions of the
-character specify different actors.</p>
-</note>
-<p>The use of agent metadata is illustrated by the following example.</p>
-<table id="metadata-vocabulary-agent-example-1" role="example">
-<caption>Example Fragment &ndash; Agent Metadata</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-
-&lt;tt xml:lang="en" xmlns="http://www.w3.org/ns/ttml" xmlns:ttm="http://www.w3.org/ns/ttml#metadata"&gt;
-  &lt;head&gt;
-    <phrase role="strong">&lt;ttm:agent xml:id="connery" type="person"&gt;</phrase>
-      &lt;ttm:name type="family"&gt;Connery&lt;/ttm:name&gt;
-      &lt;ttm:name type="given"&gt;Thomas Sean&lt;/ttm:name&gt;
-      &lt;ttm:name type="alias"&gt;Sean&lt;/ttm:name&gt;
-      &lt;ttm:name type="full"&gt;Sir Thomas Sean Connery&lt;/ttm:name&gt;
-    <phrase role="strong">&lt;/ttm:agent&gt;</phrase>
-    <phrase role="strong">&lt;ttm:agent xml:id="bond" type="character"&gt;</phrase>
-      &lt;ttm:name type="family"&gt;Bond&lt;/ttm:name&gt;
-      &lt;ttm:name type="given"&gt;James&lt;/ttm:name&gt;
-      &lt;ttm:name type="alias"&gt;007&lt;/ttm:name&gt;
-      &lt;ttm:actor agent="connery"/&gt;
-    <phrase role="strong">&lt;/ttm:agent&gt;</phrase>
-  &lt;/head&gt;
-  &lt;body&gt;
-    &lt;div&gt;
-      ...  
-      &lt;p <phrase role="strong">ttm:agent="bond"</phrase>&gt;I travel, a sort of licensed troubleshooter.&lt;/p&gt;
-      ...  
-    &lt;/div&gt;
-  &lt;/body&gt;
-&lt;/tt&gt;
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<note role="explanation">
-<p>In the above example, two agents, a real (person) agent, Sean
-Connery, and a fictitious (character) agent, James Bond, are defined,
-where the latter is linked to the former by means of the a
-<el>ttm:actor</el> element. A reference is then made from content (the
-<el>p</el> element) to the character agent associated with
-(responsible for producing) that content. Note that in this example
-the <el>ttm:agent</el> metadata items are specified as immediate
-children of the document's <el>head</el> element rather than being
-placed in a container <el>metadata</el> element.</p>
-</note>
-</div3>
-<div3 id="metadata-vocabulary-name">
-<head>ttm:name</head>
-<p>The <el>ttm:name</el> element is used to specify a name of a person, character,
-group, or organization.</p>
-<table id="elt-syntax-metadata-name" role="syntax">
-<caption>XML Representation &ndash; Element Information Item: ttm:name</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;ttm:name
-  <phrase role="reqattr">type</phrase> = (<emph>full</emph>|<emph>family</emph>|<emph>given</emph>|<emph>alias</emph>|<emph>other</emph>)
-  <loc href="#content-attribute-id">xml:id</loc> = ID
-  <loc href="#content-attribute-lang">xml:lang</loc> = string
-  <loc href="#content-attribute-space">xml:space</loc> = (<emph>default</emph>|<emph>preserve</emph>)
-  {<emph>any attribute not in default or any TT namespace</emph>}&gt;
-  <emph>Content:</emph> #PCDATA
-&lt;/ttm:name&gt;
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p>A <att>type</att> attribute must be specified on each <el>ttm:name</el> element, and,
-if specified, must have one of the following values:</p>
-<ulist>
-<item><p><el>full</el></p></item>
-<item><p><el>family</el></p></item>
-<item><p><el>given</el></p></item>
-<item><p><el>alias</el></p></item>
-<item><p><el>other</el></p></item>
-</ulist>
-<p>The relationship between the type of a name and the syntactic expression of the name
-is not defined by this specification.</p>
-<p>Two examples of the <el>ttm:name</el> element are shown above in
-<specref ref="metadata-vocabulary-agent-example-1"/>.</p>
-</div3>
-<div3 id="metadata-vocabulary-actor">
-<head>ttm:actor</head>
-<p>The <el>ttm:actor</el> element is used to link the definition of a (role-based) character
-agent with another agent that portrays the character.</p>
-<table id="elt-syntax-metadata-actor" role="syntax">
-<caption>XML Representation &ndash; Element Information Item: ttm:actor</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;ttm:actor
-  <phrase role="reqattr">agent</phrase> = IDREF
-  <loc href="#content-attribute-id">xml:id</loc> = ID
-  <loc href="#content-attribute-lang">xml:lang</loc> = string
-  <loc href="#content-attribute-space">xml:space</loc> = (<emph>default</emph>|<emph>preserve</emph>)
-  {<emph>any attribute not in default or any TT namespace</emph>}&gt;
-  <emph>Content:</emph> EMPTY
-&lt;/ttm:actor&gt;
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p>The <att>agent</att> attribute of a <el>ttm:actor</el> element must
-reference a <el>ttm:agent</el> element that denotes the person,
-group, or organization acting the part of a character.</p>
-<p>An example of the <el>ttm:actor</el> element is shown above in
-<specref ref="metadata-vocabulary-agent-example-1"/>.</p>
-</div3>
-</div2>
-<div2 id="metadata-attribute-vocabulary">
-<head>Metadata Attribute Vocabulary</head>
-<p>This section specifies the following attributes in the TT Metadata Namespace
-for use with the <el>metadata</el> element and with certain content elements:</p>
-<ulist>
-<item><p><specref ref="metadata-attribute-agent"/></p></item>
-<item><p><specref ref="metadata-attribute-role"/></p></item>
-</ulist>
-<note role="explanation">
-<p>Only certain metadata item attributes may be used with content elements. See
-the definitions of content elements to determine permissible usage.</p>
-</note>
-<div3 id="metadata-attribute-agent">
-<head>ttm:agent</head>
-<p>The <att>ttm:agent</att> attribute takes an <code>IDREFS</code>
-value, and is used with certain content elements to designate the
-agents that perform or are
-involved in the performance of the content.</p>
-<p>If specified, a <att>ttm:agent</att> attribute must reference
-<el>ttm:agent</el> element instances that appear
-as a descendent of the same document instance as
-that of the referring element.</p>
-<p>An example of the <att>ttm:agent</att> attribute is shown above in
-<specref ref="metadata-vocabulary-agent-example-1"/>.</p>
-</div3>
-<div3 id="metadata-attribute-role">
-<head>ttm:role</head>
-<p>The <att>ttm:role</att> attribute may be used by a content author
-to express
-the roles, functions, or characteristics
-of some content element that is so labeled.</p>
-<p>If specified, the value of this attribute must adhere to the following
-syntax, where
-the syntactic element <emph>S</emph> must adhere to production
-[3] <code>S</code> as defined by <bibref ref="xml10"/>&nbsp;&sect;
-2.3:</p>
-<table id="metadata-attribute-role-syntax" role="syntax">
-<caption>Syntax Representation &ndash; ttm:role</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-ttm:role
-  role ( <emph>S</emph> role )*
-
-role
-  : "action"
-  | "caption"
-  | "description"
-  | "dialog"
-  | "expletive"
-  | "kinesic"
-  | "lyrics"
-  | "music"
-  | "narration"
-  | "quality"
-  | "sound"
-  | "source"
-  | "suppressed"
-  | "reproduction"
-  | "thought"
-  | "title"
-  | "transcription"
-  | extension-role
-
-extension-role
-  : "x-" token-char+
-
-token-char
-  : { XML NameChar }    // XML 1.1 Production [4a]
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<note role="extensibility">
-<p>All values of <att>ttm:role</att> that do not start with the prefix
-<code>x-</code> are reserved for future standardization.</p>
-</note>
-</div3>
-</div2>
-</div1>
-</body>
-<back>
-<div1 id="reduced-infoset">
-<head>Reduced XML Infoset</head>
-<p><emph>This appendix is normative.</emph></p>
-<p>For the purposes of this specification, a Reduced XML Infoset is
-an XML Information Set <bibref ref="infoset"/> that consists of only the following information items
-and information item properties:</p>
-<div2 id="reduced-infoset-document">
-<head>Document Information Item</head>
-<ulist>
-<item><p><code>[document element]</code></p></item>
-</ulist>
-</div2>
-<div2 id="reduced-infoset-element">
-<head>Element Information Item</head>
-<ulist>
-<item><p><code>[namespace URI]</code></p></item>
-<item><p><code>[local name]</code></p></item>
-<item><p><code>[children]</code></p></item>
-<item><p><code>[attributes]</code></p></item>
-</ulist>
-<p>Child information items <code>[children]</code> are reduced to 
-only element and character information items.</p>
-</div2>
-<div2 id="reduced-infoset-attribute">
-<head>Attribute Information Item</head>
-<ulist>
-<item><p><code>[namespace URI]</code></p></item>
-<item><p><code>[local name]</code></p></item>
-<item><p><code>[normalized value]</code></p></item>
-</ulist>
-</div2>
-<div2 id="reduced-infoset-character">
-<head>Character Information Item</head>
-<ulist>
-<item><p><code>[character code]</code></p></item>
-</ulist>
-<p>Contiguous character information items are not required to be represented distinctly,
-but may be aggregated (chunked) into a sequence of character codes (i.e., a character string).</p>
-</div2>
-</div1>
-<div1 id="schemas">
-<head>Schemas</head>
-<p><emph>This appendix is normative.</emph></p>
-<p>This appendix specifies the following schemas for use with
-DFXP Content document instances:</p>
-<ulist>
-<item><p>Relax NG, Compact Syntax (RNC) Schema</p></item>
-<item><p>XML Schema Definition (XSD) Schema</p></item>
-</ulist>
-<p>In any case where a schema specified by this appendix differs from the
-normative definitions of document type, element type, or attribute type
-as defined by the body of this specification, then the body of this
-specification takes precedence.</p>
-<div2 id="dfxp-schema-rnc">
-<head>Relax NG Schema</head>
-<p>This section specifies a Relax NG Compact Syntax (RNC) <bibref ref="rng"/> based schema
-for DFXP Content, also available in a <loc href="rnc/schema.zip">ZIP
-Archive</loc>.</p>
-<div3 id="rnc-dfxp-driver-schema">
-<head>Driver</head>
-<eg xml:space="preserve">&rnc-dfxp-driver;</eg>
-</div3>
-<div3 id="rnc-dfxp-modules">
-<head>Modules</head>
-<div4 id="rnc-dfxp-animation-module">
-<head>Animation Module</head>
-<eg xml:space="preserve">&rnc-dfxp-animation-module;</eg>
-</div4>
-<div4 id="rnc-dfxp-classes-module">
-<head>Classes Module</head>
-<eg xml:space="preserve">&rnc-dfxp-classes-module;</eg>
-</div4>
-<div4 id="rnc-dfxp-content-module">
-<head>Content Module</head>
-<eg xml:space="preserve">&rnc-dfxp-content-module;</eg>
-</div4>
-<div4 id="rnc-dfxp-core-attribs-module">
-<head>Core Attributes Module</head>
-<eg xml:space="preserve">&rnc-dfxp-core-attribs-module;</eg>
-</div4>
-<div4 id="rnc-dfxp-datatypes-module">
-<head>Data Types Module</head>
-<eg xml:space="preserve">&rnc-dfxp-datatypes-module;</eg>
-</div4>
-<div4 id="rnc-dfxp-document-module">
-<head>Document Module</head>
-<eg xml:space="preserve">&rnc-dfxp-document-module;</eg>
-</div4>
-<div4 id="rnc-dfxp-head-module">
-<head>Header Module</head>
-<eg xml:space="preserve">&rnc-dfxp-head-module;</eg>
-</div4>
-<div4 id="rnc-dfxp-layout-module">
-<head>Layout Module</head>
-<eg xml:space="preserve">&rnc-dfxp-layout-module;</eg>
-</div4>
-<div4 id="rnc-dfxp-metadata-module">
-<head>Metadata Module</head>
-<eg xml:space="preserve">&rnc-dfxp-metadata-module;</eg>
-</div4>
-<div4 id="rnc-dfxp-metadata-items-module">
-<head>Metadata Items Module</head>
-<eg xml:space="preserve">&rnc-dfxp-metadata-items-module;</eg>
-</div4>
-<div4 id="rnc-dfxp-metadata-attribs-module">
-<head>Metadata Attributes Module</head>
-<eg xml:space="preserve">&rnc-dfxp-metadata-attribs-module;</eg>
-</div4>
-<div4 id="rnc-dfxp-parameters-module">
-<head>Parameters Module</head>
-<eg xml:space="preserve">&rnc-dfxp-parameters-module;</eg>
-</div4>
-<div4 id="rnc-dfxp-parameter-items-module">
-<head>Parameter Items Module</head>
-<eg xml:space="preserve">&rnc-dfxp-parameter-items-module;</eg>
-</div4>
-<div4 id="rnc-dfxp-parameter-attribs-module">
-<head>Parameter Attributes Module</head>
-<eg xml:space="preserve">&rnc-dfxp-parameter-attribs-module;</eg>
-</div4>
-<div4 id="rnc-dfxp-styling-attribs-module">
-<head>Styling Attributes Module</head>
-<eg xml:space="preserve">&rnc-dfxp-styling-attribs-module;</eg>
-</div4>
-<div4 id="rnc-dfxp-styling-module">
-<head>Styling Module</head>
-<eg xml:space="preserve">&rnc-dfxp-styling-module;</eg>
-</div4>
-<div4 id="rnc-dfxp-timing-attribs-module">
-<head>Timing Attributes Module</head>
-<eg xml:space="preserve">&rnc-dfxp-timing-attribs-module;</eg>
-</div4>
-</div3>
-</div2>
-<div2 id="dfxp-schema-xsd">
-<head>XML Schema Definition (XSD) Schema</head>
-<p>This section specifies a W3C XML Schema Definition (XSD) <bibref ref="xsd-1"/> based schema
-for DFXP Content, also available in a <loc href="xsd/schema.zip">ZIP
-Archive</loc>.</p>
-<div3 id="xsd-dfxp-driver-schema">
-<head>Driver</head>
-<eg xml:space="preserve">&xsd-dfxp-driver;</eg>
-</div3>
-<div3 id="xsd-dfxp-modules">
-<head>Modules</head>
-<div4 id="xsd-dfxp-animation-module">
-<head>Animation Module</head>
-<eg xml:space="preserve">&xsd-dfxp-animation-module;</eg>
-</div4>
-<div4 id="xsd-dfxp-content-module">
-<head>Content Module</head>
-<eg xml:space="preserve">&xsd-dfxp-content-module;</eg>
-</div4>
-<div4 id="xsd-dfxp-core-attribs-module">
-<head>Core Attributes Module</head>
-<eg xml:space="preserve">&xsd-dfxp-core-attribs-module;</eg>
-</div4>
-<div4 id="xsd-dfxp-datatypes-module">
-<head>Data Types Module</head>
-<eg xml:space="preserve">&xsd-dfxp-datatypes-module;</eg>
-</div4>
-<div4 id="xsd-dfxp-document-module">
-<head>Document Module</head>
-<eg xml:space="preserve">&xsd-dfxp-document-module;</eg>
-</div4>
-<div4 id="xsd-dfxp-head-module">
-<head>Header Module</head>
-<eg xml:space="preserve">&xsd-dfxp-head-module;</eg>
-</div4>
-<div4 id="xsd-dfxp-layout-module">
-<head>Layout Module</head>
-<eg xml:space="preserve">&xsd-dfxp-layout-module;</eg>
-</div4>
-<div4 id="xsd-dfxp-metadata-module">
-<head>Metadata Module</head>
-<eg xml:space="preserve">&xsd-dfxp-metadata-module;</eg>
-</div4>
-<div4 id="xsd-dfxp-metadata-items-module">
-<head>Metadata Items Module</head>
-<eg xml:space="preserve">&xsd-dfxp-metadata-items-module;</eg>
-</div4>
-<div4 id="xsd-dfxp-metadata-attribs-module">
-<head>Metadata Attributes Module</head>
-<eg xml:space="preserve">&xsd-dfxp-metadata-attribs-module;</eg>
-</div4>
-<div4 id="xsd-dfxp-parameters-module">
-<head>Parameters Module</head>
-<eg xml:space="preserve">&xsd-dfxp-parameters-module;</eg>
-</div4>
-<div4 id="xsd-dfxp-parameter-items-module">
-<head>Parameter Items Module</head>
-<eg xml:space="preserve">&xsd-dfxp-parameter-items-module;</eg>
-</div4>
-<div4 id="xsd-dfxp-parameter-attribs-module">
-<head>Parameter Attributes Module</head>
-<eg xml:space="preserve">&xsd-dfxp-parameter-attribs-module;</eg>
-</div4>
-<div4 id="xsd-dfxp-styling-attribs-module">
-<head>Styling Attributes Module</head>
-<eg xml:space="preserve">&xsd-dfxp-styling-attribs-module;</eg>
-</div4>
-<div4 id="xsd-dfxp-styling-module">
-<head>Styling Module</head>
-<eg xml:space="preserve">&xsd-dfxp-styling-module;</eg>
-</div4>
-<div4 id="xsd-dfxp-timing-attribs-module">
-<head>Timing Attributes Module</head>
-<eg xml:space="preserve">&xsd-dfxp-timing-attribs-module;</eg>
-</div4>
-<div4 id="xsd-dfxp-xml-attrs-module">
-<head>XML Attributes Module</head>
-<eg xml:space="preserve">&xsd-dfxp-xml-attrs-module;</eg>
-</div4>
-</div3>
-</div2>
-</div1>
-<div1 id="media-type-registration">
-<head>Media Type Registration</head>
-<p><emph>This appendix is normative.</emph></p>
-<p>This appendix registers a new MIME media type,
-"application/ttml+xml" in conformance with
-<loc href="http://www.ietf.org/rfc/rfc4288.txt">BCP 13</loc> and
-<loc
-href="http://www.w3.org/2002/06/registering-mediatype.html">W3CRegMedia</loc>.
-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>
-<glist>
-<gitem>
-<label>Type name:</label>
-<def>
-<p>application</p>
-</def>
-</gitem>
-<gitem>
-<label>Subtype name:</label>
-<def>
-<p>ttml+xml</p>
-</def>
-</gitem>
-<gitem>
-<label>Required parameters:</label>
-<def>
-<p>None.</p>
-</def>
-</gitem>
-<gitem>
-<label>Optional parameters:</label>
-<def>
-<glist>
-<gitem>
-<label>charset</label>
-<def>
-<p>Same as application/xml media type, as specified in <bibref
-ref="rfc3023"/> or its successors.</p>
-</def>
-</gitem>
-<gitem>
-<label>profile</label>
-<def>
-<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
-<att>ttp:profile</att> parameter defined by
-Section
-<specref ref="parameter-attribute-profile"/>
-of the published specification.</p>
-</def>
-</gitem>
-</glist>
-</def>
-</gitem>
-<gitem>
-<label>Encoding considerations:</label>
-<def>
-<p>Same for application/xml. See <bibref ref="xml-media"/>, Section
-3.2.</p>
-</def>
-</gitem>
-<gitem>
-<label>Security considerations:</label>
-<def>
-<p>As with other XML types and as noted in
-<bibref ref="xml-media"/>
-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>
-</def>
-</gitem>
-<gitem>
-<label>Interoperability considerations:</label>
-<def>
-<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>
-</def>
-</gitem>
-<gitem>
-<label>Published specification:</label>
-<def>
-<p><loc
-href="http://www.w3.org/TR/ttml11/">Timed Text Markup Language (TTML) 1.0</loc>.</p>
-</def>
-</gitem>
-<gitem>
-<label>Applications that use this media type:</label>
-<def>
-<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>
-</def>
-</gitem>
-<gitem>
-<label>Additional information:</label>
-<def>
-<glist>
-<gitem>
-    <label>Magic number(s):</label>
-    <def></def>
-</gitem>
-<gitem>
-    <label>File extension(s):</label>
-    <def><p>.ttml</p></def>
-</gitem>
-<gitem>
-    <label>Macintosh file type code(s):</label>
-    <def><p>"TTML"</p></def>
-</gitem>
-<gitem>
-<label>Fragment identifiers:</label>
-<def><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 <loc
-href="http://www.w3.org/TR/ttml11/">Timed Text Markup Language (TTML) 1.0</loc> specification.</p></def>
-</gitem>
-</glist>
-</def>
-</gitem>
-<gitem>
-<label>Person &amp; email address to contact for further information:</label>
-<def>
-<p>Timed Text Working Group (public-tt@w3.org)</p>
-</def>
-</gitem>
-<gitem>
-<label>Intended usage:</label>
-<def>
-<p>COMMON</p>
-</def>
-</gitem>
-<gitem>
-<label>Restrictions on usage:</label>
-<def>
-<p>None</p>
-</def>
-</gitem>
-<gitem>
-<label>Author:</label>
-<def>
-<p>The published specification is a work product of the World Wide Web
-Consortium's Timed Text (TT) Working Group.</p>
-</def>
-</gitem>
-<gitem>
-<label>Change controller:</label>
-<def>
-<p>The W3C has change control over this specification.</p>
-</def>
-</gitem>
-</glist>
-</div1>
-<div1 id="features">
-<head>Features</head>
-<p><emph>This appendix is normative.</emph></p>
-<p>This appendix specifies (1) a set of feature designations, each of which
-labels one or more syntactic and/or semantic features defined by this
-specification, and (2) for each designated feature, whether the feature is mandatory
-or optional for a transformation or presentation processor.</p>
-<note>
-<p>A TTML processor is said to <emph>implement the transformation semantics</emph> or
-<emph>implement the presentation semantics</emph> of feature designation <emph>F</emph>
-if it satisfies the requirements of this appendix with respect to the definition of
-feature designation <emph>F</emph> as pertains to transformation or
-presentation processing, respectively.</p>
-</note>
-<div2 id="feature-designations">
-<head>Feature Designations</head>
-<p>A feature designation is expressed as a string that adheres to the following
-form:</p>
-<eg xml:space="preserve">
-feature-designation
-  : feature-namespace designation
-
-feature-namespace
-  : <emph>TT Feature Namespace</emph>                    // http://www.w3.org/ns/ttml/feature/
-
-designation
-  : "#" token-char+
-
-token-char
-  : { XML NameChar }                        // XML 1.1 Production [4a]
-</eg>
-<p>All values of <code>feature-designation</code> not defined by this specification are reserved
-for future standardization.</p>
-<p>The following sub-sections define all feature designations, expressed
-as relative URIs (fragment identifiers) with respect to the 
-TT Feature Namespace base URI.</p>
-<div3 id="feature-animation">
-<head>#animation</head>
-<p>A TTML transformation processor supports the <code>#animation</code>
-feature if it recognizes and is capable of transforming the following
-vocabulary defined by <specref ref="animation"/>:</p>
-<ulist>
-<item><p><loc href="#animation-vocabulary-set"><el>set</el></loc></p></item>
-</ulist>
-<p>A TTML presentation processor supports the <code>#animation</code>
-feature if it implements presentation semantic support for the
-same vocabulary enumerated above.</p>
-</div3>
-<div3 id="feature-backgroundColor">
-<head>#backgroundColor</head>
-<p>A TTML transformation processor supports the
-<code>#backgroundColor</code> feature if it recognizes and is capable of
-transforming the <loc
-href="#style-attribute-backgroundColor"><att>tts:backgroundColor</att></loc>
-attribute.</p>
-<p>A TTML presentation processor supports the
-<code>#backgroundColor</code> feature if it (1) implements presentation semantic support
-for the <loc
-href="#style-attribute-backgroundColor"><att>tts:backgroundColor</att></loc>
-attribute
-and (2) is capable of displaying or generating an output display
-signal that distinguishes between at least sixteen (16) values of color,
-including all primary and secondary colors of the SRGB color space.</p>
-</div3>
-<div3 id="feature-backgroundColor-block">
-<head>#backgroundColor-block</head>
-<p>A TTML transformation processor supports the
-<code>#backgroundColor-block</code> feature if it recognizes and is
-capable of transforming all defined values of the <loc
-href="#style-attribute-backgroundColor"><att>tts:backgroundColor</att></loc>
-attribute when applied to a content element that would generate a
-block area during presentation processing.</p>
-<p>A TTML presentation processor supports the
-<code>#backgroundColor-block</code> feature if it (1) implements presentation semantic
-support for the <loc
-href="#style-attribute-backgroundColor"><att>tts:backgroundColor</att></loc>
-attribute when applied to a content element that generates a
-block area
-and (2) is capable of displaying or generating an output display
-signal that distinguishes between at least sixteen (16) values of color,
-including all primary and secondary colors of the SRGB color space.</p>
-</div3>
-<div3 id="feature-backgroundColor-inline">
-<head>#backgroundColor-inline</head>
-<p>A TTML transformation processor supports the
-<code>#backgroundColor-inline</code> feature if it recognizes and is
-capable of transforming all defined values of the <loc
-href="#style-attribute-backgroundColor"><att>tts:backgroundColor</att></loc>
-attribute when applied to a content element that would generate an
-inline area during presentation processing.</p>
-<p>A TTML presentation processor supports the
-<code>#backgroundColor-inline</code> feature if it (1) implements presentation semantic
-support for the <loc
-href="#style-attribute-backgroundColor"><att>tts:backgroundColor</att></loc>
-attribute when applied to a content element that generates an
-inline area
-and (2) is capable of displaying or generating an output display
-signal that distinguishes between at least sixteen (16) values of color,
-including all primary and secondary colors of the SRGB color space.</p>
-</div3>
-<div3 id="feature-backgroundColor-region">
-<head>#backgroundColor-region</head>
-<p>A TTML transformation processor supports the
-<code>#backgroundColor-region</code> feature if it recognizes and is
-capable of transforming all defined values of the <loc
-href="#style-attribute-backgroundColor"><att>tts:backgroundColor</att></loc>
-attribute when applied to a <loc
-href="#layout-vocabulary-region"><el>region</el></loc> element.</p>
-<p>A TTML presentation processor supports the
-<code>#backgroundColor-region</code> feature if it (1) implements presentation semantic
-support for the <loc
-href="#style-attribute-backgroundColor"><att>tts:backgroundColor</att></loc>
-attribute when applied to a <loc
-href="#layout-vocabulary-region"><el>region</el></loc> element
-and (2) is capable of displaying or generating an output display
-signal that distinguishes between at least sixteen (16) values of color,
-including all primary and secondary colors of the SRGB color space
-.</p>
-</div3>
-<div3 id="feature-bidi">
-<head>#bidi</head>
-<p>A TTML processor supports the <code>#bidi</code> feature if it
-supports the following features:</p>
-<ulist>
-<item><p><loc
-href="#feature-direction"><code>#direction</code></loc></p></item>
-<item><p><loc
-href="#feature-unicodeBidi"><code>#unicodeBidi</code></loc></p></item>
-<item><p><loc
-href="#feature-writingMode-horizontal"><code>#writingMode-horizontal</code></loc></p></item>
-</ulist>
-</div3>
-<div3 id="feature-cellResolution">
-<head>#cellResolution</head>
-<p>A TTML transformation processor supports the
-<code>#cellResolution</code> feature if it recognizes and is capable of
-transforming the <loc
-href="#parameter-attribute-cellResolution"><att>ttp:cellResolution</att></loc>
-attribute.</p>
-<p>A TTML presentation processor supports the
-<code>#cellResolution</code> feature if it implements presentation semantic support
-for the <loc
-href="#parameter-attribute-cellResolution"><att>ttp:cellResolution</att></loc>
-attribute.</p>
-</div3>
-<div3 id="feature-clockMode">
-<head>#clockMode</head>
-<p>A TTML transformation processor supports the
-<code>#clockMode</code> feature if it recognizes and is capable of
-transforming the <loc
-href="#parameter-attribute-clockMode"><att>ttp:clockMode</att></loc>
-attribute.</p>
-<p>A TTML presentation processor supports the
-<code>#clockMode</code> feature if it implements presentation semantic support
-for the <loc
-href="#parameter-attribute-clockMode"><att>ttp:clockMode</att></loc>
-attribute.</p>
-</div3>
-<div3 id="feature-clockMode-gps">
-<head>#clockMode-gps</head>
-<p>A TTML transformation processor supports the
-<code>#clockMode-gps</code> feature if it recognizes and is capable of
-transforming the <code>gps</code> value of the <loc
-href="#parameter-attribute-clockMode"><att>ttp:clockMode</att></loc>
-attribute.</p>
-<p>A TTML presentation processor supports the
-<code>#clockMode-gps</code> feature if it implements presentation semantic support
-for the <code>gps</code> value of the <loc
-href="#parameter-attribute-clockMode"><att>ttp:clockMode</att></loc>
-attribute.</p>
-</div3>
-<div3 id="feature-clockMode-local">
-<head>#clockMode-local</head>
-<p>A TTML transformation processor supports the
-<code>#clockMode-local</code> feature if it recognizes and is capable of
-transforming the <code>local</code> value of the <loc
-href="#parameter-attribute-clockMode"><att>ttp:clockMode</att></loc>
-attribute.</p>
-<p>A TTML presentation processor supports the
-<code>#clockMode-local</code> feature if it implements presentation semantic support
-for the <code>local</code> value of the <loc
-href="#parameter-attribute-clockMode"><att>ttp:clockMode</att></loc>
-attribute.</p>
-</div3>
-<div3 id="feature-clockMode-utc">
-<head>#clockMode-utc</head>
-<p>A TTML transformation processor supports the
-<code>#clockMode-utc</code> feature if it recognizes and is capable of
-transforming the <code>utc</code> value of the <loc
-href="#parameter-attribute-clockMode"><att>ttp:clockMode</att></loc>
-attribute.</p>
-<p>A TTML presentation processor supports the
-<code>#clockMode-utc</code> feature if it implements presentation semantic support
-for the <code>utc</code> value of the <loc
-href="#parameter-attribute-clockMode"><att>ttp:clockMode</att></loc>
-attribute.</p>
-</div3>
-<div3 id="feature-color">
-<head>#color</head>
-<p>A TTML transformation processor supports the
-<code>#color</code> feature if it recognizes and is capable of
-transforming the <loc
-href="#style-attribute-color"><att>tts:color</att></loc>
-attribute.</p>
-<p>A TTML presentation processor supports the
-<code>#color</code> feature if it (1) implements presentation semantic support
-for the <loc
-href="#style-attribute-color"><att>tts:color</att></loc>
-attribute
-and (2) is capable of displaying or generating an output display
-signal that distinguishes between at least sixteen (16) values of color,
-including all primary and secondary colors of the SRGB color space.</p>
-</div3>
-<div3 id="feature-content">
-<head>#content</head>
-<p>A TTML transformation processor supports the <code>#content</code>
-feature if it recognizes and is capable of transforming the following
-vocabulary defined by <specref ref="content"/>:</p>
-<ulist>
-<item><p><loc href="#document-structure-vocabulary-body"><el>body</el></loc></p></item>
-<item><p><loc href="#content-vocabulary-div"><el>div</el></loc></p></item>
-<item><p><loc href="#content-vocabulary-p"><el>p</el></loc></p></item>
-<item><p><loc href="#content-vocabulary-span"><el>span</el></loc></p></item>
-<item><p><loc href="#content-vocabulary-br"><el>br</el></loc></p></item>
-</ulist>
-<p>A TTML presentation processor supports the <code>#content</code>
-feature if it implements presentation semantic support for the
-same vocabulary enumerated above.</p>
-</div3>
-<div3 id="feature-core">
-<head>#core</head>
-<p>A TTML transformation processor supports the <code>#core</code>
-feature if it recognizes and is capable of transforming the following
-core attributes vocabulary defined by <specref ref="content"/>:</p>
-<ulist>
-<item><p><loc href="#content-attribute-id">@<att>xml:id</att></loc></p></item>
-<item><p><loc href="#content-attribute-id">@<att>xml:lang</att></loc></p></item>
-<item><p><loc href="#content-attribute-id">@<att>xml:space</att></loc></p></item>
-</ulist>
-<p>A TTML presentation processor supports the <code>#core</code>
-feature if it implements presentation semantic support for the
-same vocabulary enumerated above.</p>
-</div3>
-<div3 id="feature-direction">
-<head>#direction</head>
-<p>A TTML transformation processor supports the
-<code>#direction</code> feature if it recognizes and is capable of
-transforming all defined values of the <loc
-href="#style-attribute-direction"><att>tts:direction</att></loc>
-attribute.</p>
-<p>A TTML presentation processor supports the
-<code>#direction</code> feature if it implements presentation semantic support
-for all defined values of the <loc
-href="#style-attribute-direction"><att>tts:direction</att></loc>
-attribute.</p>
-</div3>
-<div3 id="feature-display">
-<head>#display</head>
-<p>A TTML transformation processor supports the
-<code>#display</code> feature if it recognizes and is capable of
-transforming all defined values of the <loc
-href="#style-attribute-display"><att>tts:display</att></loc>
-attribute.</p>
-<p>A TTML presentation processor supports the
-<code>#display</code> feature if it implements presentation semantic support
-for all defined values of the <loc
-href="#style-attribute-display"><att>tts:display</att></loc>
-attribute.</p>
-</div3>
-<div3 id="feature-display-block">
-<head>#display-block</head>
-<p>A TTML transformation processor supports the
-<code>#display-block</code> feature if it recognizes and is
-capable of transforming all defined values of the <loc
-href="#style-attribute-display"><att>tts:display</att></loc>
-attribute when applied to a content element that would generate a
-block area during presentation processing.</p>
-<p>A TTML presentation processor supports the
-<code>#display-block</code> feature if it implements presentation semantic
-support for all defined values of the <loc
-href="#style-attribute-display"><att>tts:display</att></loc>
-attribute when applied to a content element that generates a
-block area.</p>
-</div3>
-<div3 id="feature-display-inline">
-<head>#display-inline</head>
-<p>A TTML transformation processor supports the
-<code>#display-inline</code> feature if it recognizes and is
-capable of transforming all defined values of the <loc
-href="#style-attribute-display"><att>tts:display</att></loc>
-attribute when applied to a content element that would generate an
-inline area during presentation processing.</p>
-<p>A TTML presentation processor supports the
-<code>#display-inline</code> feature if it implements presentation semantic
-support for all defined values of the <loc
-href="#style-attribute-display"><att>tts:display</att></loc>
-attribute when applied to a content element that generates an
-inline area.</p>
-</div3>
-<div3 id="feature-display-region">
-<head>#display-region</head>
-<p>A TTML transformation processor supports the
-<code>#display-region</code> feature if it recognizes and is
-capable of transforming all defined values of the <loc
-href="#style-attribute-display"><att>tts:display</att></loc>
-attribute when applied to a <loc
-href="#layout-vocabulary-region"><el>region</el></loc> element.</p>
-<p>A TTML presentation processor supports the
-<code>#display-region</code> feature if it implements presentation semantic
-support for all defined values of the <loc
-href="#style-attribute-display"><att>tts:display</att></loc>
-attribute when applied to a <loc
-href="#layout-vocabulary-region"><el>region</el></loc> element.</p>
-</div3>
-<div3 id="feature-displayAlign">
-<head>#displayAlign</head>
-<p>A TTML transformation processor supports the
-<code>#displayAlign</code> feature if it recognizes and is capable of
-transforming all defined values of the <loc
-href="#style-attribute-displayAlign"><att>tts:displayAlign</att></loc>
-attribute.</p>
-<p>A TTML presentation processor supports the
-<code>#displayAlign</code> feature if it implements presentation semantic support
-for all defined values of the <loc
-href="#style-attribute-displayAlign"><att>tts:displayAlign</att></loc>
-attribute.</p>
-</div3>
-<div3 id="feature-dropMode">
-<head>#dropMode</head>
-<p>A TTML transformation processor supports the
-<code>#dropMode</code> feature if it recognizes and is capable of
-transforming the <loc
-href="#parameter-attribute-dropMode"><att>ttp:dropMode</att></loc>
-attribute.</p>
-<p>A TTML presentation processor supports the
-<code>#dropMode</code> feature if it implements presentation semantic support
-for the <loc
-href="#parameter-attribute-dropMode"><att>ttp:dropMode</att></loc>
-attribute.</p>
-</div3>
-<div3 id="feature-dropMode-dropNTSC">
-<head>#dropMode-dropNTSC</head>
-<p>A TTML transformation processor supports the
-<code>#dropMode-dropNTSC</code> feature if it recognizes and is capable of
-transforming the <code>dropNTSC</code> value of the <loc
-href="#parameter-attribute-dropMode"><att>ttp:dropMode</att></loc>
-attribute.</p>
-<p>A TTML presentation processor supports the
-<code>#dropMode-dropNTSC</code> feature if it implements presentation semantic support
-for the <code>dropNTSC</code> value of the <loc
-href="#parameter-attribute-dropMode"><att>ttp:dropMode</att></loc>
-attribute.</p>
-</div3>
-<div3 id="feature-dropMode-dropPAL">
-<head>#dropMode-dropPAL</head>
-<p>A TTML transformation processor supports the
-<code>#dropMode-dropPAL</code> feature if it recognizes and is capable of
-transforming the <code>dropPAL</code> value of the <loc
-href="#parameter-attribute-dropMode"><att>ttp:dropMode</att></loc>
-attribute.</p>
-<p>A TTML presentation processor supports the
-<code>#dropMode-dropPAL</code> feature if it implements presentation semantic support
-for the <code>dropPAL</code> value of the <loc
-href="#parameter-attribute-dropMode"><att>ttp:dropMode</att></loc>
-attribute.</p>
-</div3>
-<div3 id="feature-dropMode-nonDrop">
-<head>#dropMode-nonDrop</head>
-<p>A TTML transformation processor supports the
-<code>#dropMode-nonDrop</code> feature if it recognizes and is capable of
-transforming the <code>nonDrop</code> value of the <loc
-href="#parameter-attribute-dropMode"><att>ttp:dropMode</att></loc>
-attribute.</p>
-<p>A TTML presentation processor supports the
-<code>#dropMode-nonDrop</code> feature if it implements presentation semantic support
-for the <code>nonDrop</code> value of the <loc
-href="#parameter-attribute-dropMode"><att>ttp:dropMode</att></loc>
-attribute.</p>
-</div3>
-<div3 id="feature-extent">
-<head>#extent</head>
-<p>A TTML transformation processor supports the
-<code>#extent</code> feature if it recognizes and is capable of
-transforming the <loc
-href="#style-attribute-extent"><att>tts:extent</att></loc>
-attribute.</p>
-<p>A TTML presentation processor supports the
-<code>#extent</code> feature if it implements presentation semantic support for
-the <loc
-href="#style-attribute-extent"><att>tts:extent</att></loc>
-attribute.</p>
-</div3>
-<div3 id="feature-extent-region">
-<head>#extent-region</head>
-<p>A TTML transformation processor supports the
-<code>#extent-region</code> feature if it recognizes and is capable of
-transforming the <loc
-href="#style-attribute-extent"><att>tts:extent</att></loc>
-attribute when applied to a <loc
-href="#layout-vocabulary-region"><el>region</el></loc> element.</p>
-<p>A TTML presentation processor supports the
-<code>#extent-region</code> feature if it implements presentation semantic support for
-the <loc
-href="#style-attribute-extent"><att>tts:extent</att></loc>
-attribute when applied to a <loc
-href="#layout-vocabulary-region"><el>region</el></loc> element.</p>
-</div3>
-<div3 id="feature-extent-root">
-<head>#extent-root</head>
-<p>A TTML transformation processor supports the
-<code>#extent-root</code> feature if it recognizes and is capable of
-transforming the <loc
-href="#style-attribute-extent"><att>tts:extent</att></loc>
-attribute when applied to the <loc
-href="#document-structure-vocabulary-tt"><el>tt</el></loc> element.</p>
-<p>A TTML presentation processor supports the
-<code>#extent-root</code> feature if it implements presentation semantic support for
-the <loc
-href="#style-attribute-extent"><att>tts:extent</att></loc>
-attribute when applied to a <loc
-href="#document-structure-vocabulary-tt"><el>tt</el></loc> element.</p>
-</div3>
-<div3 id="feature-fontFamily">
-<head>#fontFamily</head>
-<p>A TTML transformation processor supports the
-<code>#fontFamily</code> feature if it recognizes and is capable of
-transforming the <loc
-href="#style-attribute-fontFamily"><att>tts:fontFamily</att></loc>
-attribute.</p>
-<p>A TTML presentation processor supports the
-<code>#fontFamily</code> feature if it implements presentation semantic support
-for the <loc
-href="#style-attribute-fontFamily"><att>tts:fontFamily</att></loc>
-attribute.</p>
-</div3>
-<div3 id="feature-fontFamily-generic">
-<head>#fontFamily-generic</head>
-<p>A TTML transformation processor supports the
-<code>#fontFamily-generic</code> feature if it recognizes and is
-capable of transforming <loc
-href="#style-value-genericFamilyName">&lt;genericFamilyName&gt;</loc>
-values when used with the <loc
-href="#style-attribute-fontFamily"><att>tts:fontFamily</att></loc>
-attribute.</p>
-<p>A TTML presentation processor supports the
-<code>#fontFamily-generic</code> feature if it implements presentation semantic
-support for <loc
-href="#style-value-genericFamilyName">&lt;genericFamilyName&gt;</loc>
-values when used with the <loc
-href="#style-attribute-fontFamily"><att>tts:fontFamily</att></loc>
-attribute.</p>
-</div3>
-<div3 id="feature-fontFamily-non-generic">
-<head>#fontFamily-non-generic</head>
-<p>A TTML transformation processor supports the
-<code>#fontFamily-non-generic</code> feature if it recognizes and is
-capable of transforming <loc
-href="#style-value-familyName">&lt;familyName&gt;</loc>
-values when used with the <loc
-href="#style-attribute-fontFamily"><att>tts:fontFamily</att></loc>
-attribute.</p>
-<p>A TTML presentation processor supports the
-<code>#fontFamily-non-generic</code> feature if it implements presentation semantic
-support for <loc
-href="#style-value-familyName">&lt;familyName&gt;</loc>
-values when used with the <loc
-href="#style-attribute-fontFamily"><att>tts:fontFamily</att></loc>
-attribute.</p>
-</div3>
-<div3 id="feature-fontSize">
-<head>#fontSize</head>
-<p>A TTML transformation processor supports the
-<code>#fontSize</code> feature if it recognizes and is capable of
-transforming the <loc
-href="#style-attribute-fontSize"><att>tts:fontSize</att></loc>
-attribute.</p>
-<p>A TTML presentation processor supports the
-<code>#fontSize</code> feature if it implements presentation semantic support
-for the <loc
-href="#style-attribute-fontSize"><att>tts:fontSize</att></loc>
-attribute.</p>
-</div3>
-<div3 id="feature-fontSize-anamorphic">
-<head>#fontSize-anamorphic</head>
-<p>A TTML transformation processor supports the
-<code>#fontSize-anamorphic</code> feature if it recognizes and is
-capable of transforming values of the <loc
-href="#style-attribute-fontSize"><att>tts:fontSize</att></loc>
-attribute that consist of two <loc
-href="#style-value-length">&lt;length&gt;</loc> specifications.</p>
-<p>A TTML presentation processor supports the
-<code>#fontSize-anamorphic</code> feature if it implements presentation semantic
-support for defined values of the <loc
-href="#style-attribute-fontSize"><att>tts:fontSize</att></loc>
-attribute that consist of two <loc
-href="#style-value-length">&lt;length&gt;</loc> specifications.</p>
-</div3>
-<div3 id="feature-fontSize-isomorphic">
-<head>#fontSize-isomorphic</head>
-<p>A TTML transformation processor supports the
-<code>#fontSize-isomorphic</code> feature if it recognizes and is
-capable of transforming values of the <loc
-href="#style-attribute-fontSize"><att>tts:fontSize</att></loc>
-attribute that consist of a single <loc
-href="#style-value-length">&lt;length&gt;</loc> specification.</p>
-<p>A TTML presentation processor supports the
-<code>#fontSize-isomorphic</code> feature if it implements presentation semantic
-support for defined values of the <loc
-href="#style-attribute-fontSize"><att>tts:fontSize</att></loc>
-attribute that consist of a single <loc
-href="#style-value-length">&lt;length&gt;</loc> specification.</p>
-</div3>
-<div3 id="feature-fontStyle">
-<head>#fontStyle</head>
-<p>A TTML transformation processor supports the
-<code>#fontStyle</code> feature if it recognizes and is capable of
-transforming all defined values of the <loc
-href="#style-attribute-fontStyle"><att>tts:fontStyle</att></loc>
-attribute.</p>
-<p>A TTML presentation processor supports the
-<code>#fontStyle</code> feature if it implements presentation semantic support
-for all defined values of the <loc
-href="#style-attribute-fontStyle"><att>tts:fontStyle</att></loc>
-attribute.</p>
-</div3>
-<div3 id="feature-fontStyle-italic">
-<head>#fontStyle-italic</head>
-<p>A TTML transformation processor supports the
-<code>#fontStyle-italic</code> feature if it recognizes and is
-capable of transforming the <code>italic</code> value of the <loc
-href="#style-attribute-fontStyle"><att>tts:fontStyle</att></loc>
-attribute.</p>
-<p>A TTML presentation processor supports the
-<code>#fontStyle-italic</code> feature if it implements presentation semantic
-support for the <code>italic</code> of the <loc
-href="#style-attribute-fontStyle"><att>tts:fontStyle</att></loc>
-attribute.</p>
-</div3>
-<div3 id="feature-fontStyle-oblique">
-<head>#fontStyle-oblique</head>
-<p>A TTML transformation processor supports the
-<code>#fontStyle-oblique</code> feature if it recognizes and is
-capable of transforming the <code>oblique</code> value of the <loc
-href="#style-attribute-fontStyle"><att>tts:fontStyle</att></loc>
-attribute.</p>
-<p>A TTML presentation processor supports the
-<code>#fontStyle-oblique</code> feature if it implements presentation semantic
-support for the <code>oblique</code> of the <loc
-href="#style-attribute-fontStyle"><att>tts:fontStyle</att></loc>
-attribute.</p>
-</div3>
-<div3 id="feature-fontWeight">
-<head>#fontWeight</head>
-<p>A TTML transformation processor supports the
-<code>#fontWeight</code> feature if it recognizes and is capable of
-transforming all defined values of the <loc
-href="#style-attribute-fontWeight"><att>tts:fontWeight</att></loc>
-attribute.</p>
-<p>A TTML presentation processor supports the
-<code>#fontWeight</code> feature if it implements presentation semantic support
-for all defined values of the <loc
-href="#style-attribute-fontWeight"><att>tts:fontWeight</att></loc>
-attribute.</p>
-</div3>
-<div3 id="feature-fontWeight-bold">
-<head>#fontWeight-bold</head>
-<p>A TTML transformation processor supports the
-<code>#fontWeight-bold</code> feature if it recognizes and is
-capable of transforming <code>bold</code> value of the <loc
-href="#style-attribute-fontWeight"><att>tts:fontWeight</att></loc>
-attribute.</p>
-<p>A TTML presentation processor supports the
-<code>#fontWeight-bold</code> feature if it implements presentation semantic
-support for the <code>bold</code> of the <loc
-href="#style-attribute-fontWeight"><att>tts:fontWeight</att></loc>
-attribute.</p>
-</div3>
-<div3 id="feature-frameRate">
-<head>#frameRate</head>
-<p>A TTML transformation processor supports the
-<code>#frameRate</code> feature if it recognizes and is capable of
-transforming the <loc
-href="#parameter-attribute-frameRate"><att>ttp:frameRate</att></loc>
-attribute.</p>
-<p>A TTML presentation processor supports the
-<code>#frameRate</code> feature if it implements presentation semantic support
-for the <loc
-href="#parameter-attribute-frameRate"><att>ttp:frameRate</att></loc>
-attribute.</p>
-</div3>
-<div3 id="feature-frameRateMultiplier">
-<head>#frameRateMultiplier</head>
-<p>A TTML transformation processor supports the
-<code>#frameRateMultiplier</code> feature if it recognizes and is capable of
-transforming the <loc
-href="#parameter-attribute-frameRateMultiplier"><att>ttp:frameRateMultiplier</att></loc>
-attribute.</p>
-<p>A TTML presentation processor supports the
-<code>#frameRateMultiplier</code> feature if it implements presentation semantic support
-for the <loc
-href="#parameter-attribute-frameRateMultiplier"><att>ttp:frameRateMultiplier</att></loc>
-attribute.</p>
-</div3>
-<div3 id="feature-layout">
-<head>#layout</head>
-<p>A TTML transformation processor supports the <code>#layout</code>
-feature if it (1) recognizes and is capable of transforming the following
-vocabulary defined by <specref ref="layout"/>:</p>
-<ulist>
-<item><p><loc href="#layout-vocabulary-layout"><el>layout</el></loc></p></item>
-<item><p><loc href="#layout-vocabulary-region"><el>region</el></loc></p></item>
-<item><p><loc href="#layout-attribute-region">@<att>region</att></loc></p></item>
-</ulist>
-<p>and (2) supports the following attributes when applied to the
-<loc href="#layout-vocabulary-region"><el>region</el></loc> element:</p>
-<ulist>
-<item><p><loc
-href="#style-attribute-extent"><att>tts:extent</att></loc></p></item>
-<item><p><loc
-href="#style-attribute-origin"><att>tts:origin</att></loc></p></item>
-</ulist>
-<p>A TTML presentation processor supports the <code>#layout</code>
-feature if it implements presentation semantic support for the
-same vocabulary and features enumerated above.</p>
-</div3>
-<div3 id="feature-length">
-<head>#length</head>
-<p>A TTML transformation processor supports the <code>#length</code>
-feature if it recognizes and is capable of transforming all defined
-values of the <loc href="#style-value-length">&lt;length&gt;</loc>
-style value expression.</p>
-<p>A TTML presentation processor supports the <code>#length</code>
-feature if it implements presentation semantic support for all defined values of
-the <loc href="#style-value-length">&lt;length&gt;</loc> style value
-expression.</p>
-</div3>
-<div3 id="feature-length-cell">
-<head>#length-cell</head>
-<p>A TTML transformation processor supports the
-<code>#length-cell</code> feature if it recognizes and is capable of
-transforming scalar values of the <loc
-href="#style-value-length">&lt;length&gt;</loc> style value expression
-that use <code>c</code> (cell) units.</p>
-<p>A TTML presentation processor supports the
-<code>#length-cell</code> feature if it implements presentation semantic support
-for scalar values of the <loc
-href="#style-value-length">&lt;length&gt;</loc> style value expression
-that use <code>c</code> (cell) units.</p>
-</div3>
-<div3 id="feature-length-em">
-<head>#length-em</head>
-<p>A TTML transformation processor supports the
-<code>#length-em</code> feature if it recognizes and is capable of
-transforming scalar values of the <loc
-href="#style-value-length">&lt;length&gt;</loc> style value expression
-that use <code>em</code> (EM) units.</p>
-<p>A TTML presentation processor supports the
-<code>#length-em</code> feature if it implements presentation semantic support
-for scalar values of the <loc
-href="#style-value-length">&lt;length&gt;</loc> style value expression
-that use <code>em</code> (EM) units.</p>
-</div3>
-<div3 id="feature-length-integer">
-<head>#length-integer</head>
-<p>A TTML transformation processor supports the
-<code>#length-integer</code> feature if it recognizes and is
-capable of transforming integer values of the <loc
-href="#style-value-length">&lt;length&gt;</loc> style value
-expression.</p>
-<p>A TTML presentation processor supports the
-<code>#length-integer</code> feature if it implements presentation semantic
-support for integer values of the <loc
-href="#style-value-length">&lt;length&gt;</loc> style value
-expression.
-</p>
-</div3>
-<div3 id="feature-length-negative">
-<head>#length-negative</head>
-<p>A TTML transformation processor supports the
-<code>#length-negative</code> feature if it recognizes and is
-capable of transforming negative values of the <loc
-href="#style-value-length">&lt;length&gt;</loc> style value
-expression.</p>
-<p>A TTML presentation processor supports the
-<code>#length-negative</code> feature if it implements presentation semantic
-support for negative values of the <loc
-href="#style-value-length">&lt;length&gt;</loc> style value
-expression.
-</p>
-</div3>
-<div3 id="feature-length-percentage">
-<head>#length-percentage</head>
-<p>A TTML transformation processor supports the
-<code>#length-percentage</code> feature if it recognizes and is
-capable of transforming percentage values of the <loc
-href="#style-value-length">&lt;length&gt;</loc> style value
-expression.</p>
-<p>A TTML presentation processor supports the
-<code>#length-percentage</code> feature if it implements presentation semantic
-support for percentage values of the <loc
-href="#style-value-length">&lt;length&gt;</loc> style value
-expression.
-</p>
-</div3>
-<div3 id="feature-length-pixel">
-<head>#length-pixel</head>
-<p>A TTML transformation processor supports the
-<code>#length-pixel</code> feature if it recognizes and is capable of
-transforming scalar values of the <loc
-href="#style-value-length">&lt;length&gt;</loc> style value expression
-that use <code>px</code> (pixel) units.</p>
-<p>A TTML presentation processor supports the
-<code>#length-pixel</code> feature if it implements presentation semantic support
-for scalar values of the <loc
-href="#style-value-length">&lt;length&gt;</loc> style value expression
-that use <code>px</code> (pixel) units.</p>
-</div3>
-<div3 id="feature-length-positive">
-<head>#length-positive</head>
-<p>A TTML transformation processor supports the
-<code>#length-positive</code> feature if it recognizes and is
-capable of transforming positive values of the <loc
-href="#style-value-length">&lt;length&gt;</loc> style value
-expression.</p>
-<p>A TTML presentation processor supports the
-<code>#length-positive</code> feature if it implements presentation semantic
-support for positive values of the <loc
-href="#style-value-length">&lt;length&gt;</loc> style value
-expression.
-</p>
-</div3>
-<div3 id="feature-length-real">
-<head>#length-real</head>
-<p>A TTML transformation processor supports the
-<code>#length-real</code> feature if it recognizes and is
-capable of transforming real values of the <loc
-href="#style-value-length">&lt;length&gt;</loc> style value
-expression.</p>
-<p>A TTML presentation processor supports the
-<code>#length-real</code> feature if it implements presentation semantic
-support for real values of the <loc
-href="#style-value-length">&lt;length&gt;</loc> style value
-expression.
-</p>
-</div3>
-<div3 id="feature-lineBreak-uax14">
-<head>#lineBreak-uax14</head>
-<p>A TTML transformation processor supports the
-<code>#lineBreak-uax14</code> feature if it recognizes and is capable of
-transforming requirements expressed by <bibref ref="uax14"/> into its
-target document space.</p>
-<p>A TTML presentation processor supports the
-<code>#lineBreak-uax14</code> feature if it implements presentation semantic support
-for <bibref ref="uax14"/> as applies to line breaking.</p>
-</div3>
-<div3 id="feature-lineHeight">
-<head>#lineHeight</head>
-<p>A TTML transformation processor supports the
-<code>#lineHeight</code> feature if it recognizes and is capable of
-transforming the <loc
-href="#style-attribute-lineHeight"><att>tts:lineHeight</att></loc>
-attribute.</p>
-<p>A TTML presentation processor supports the
-<code>#lineHeight</code> feature if it implements presentation semantic support for
-the <loc
-href="#style-attribute-lineHeight"><att>tts:lineHeight</att></loc>
-attribute.</p>
-</div3>
-<div3 id="feature-markerMode">
-<head>#markerMode</head>
-<p>A TTML transformation processor supports the
-<code>#markerMode</code> feature if it recognizes and is capable of
-transforming the <loc
-href="#parameter-attribute-markerMode"><att>ttp:markerMode</att></loc>
-attribute.</p>
-<p>A TTML presentation processor supports the
-<code>#markerMode</code> feature if it implements presentation semantic support
-for the <loc
-href="#parameter-attribute-markerMode"><att>ttp:markerMode</att></loc>
-attribute.</p>
-</div3>
-<div3 id="feature-markerMode-continuous">
-<head>#markerMode-continuous</head>
-<p>A TTML transformation processor supports the
-<code>#markerMode-continuous</code> feature if it recognizes and is capable of
-transforming the <code>continuous</code> value of the <loc
-href="#parameter-attribute-markerMode"><att>ttp:markerMode</att></loc>
-attribute.</p>
-<p>A TTML presentation processor supports the
-<code>#markerMode-continuous</code> feature if it implements presentation semantic support
-for the <code>continuous</code> value of the <loc
-href="#parameter-attribute-markerMode"><att>ttp:markerMode</att></loc>
-attribute.</p>
-</div3>
-<div3 id="feature-markerMode-discontinuous">
-<head>#markerMode-discontinuous</head>
-<p>A TTML transformation processor supports the
-<code>#markerMode-discontinuous</code> feature if it recognizes and is capable of
-transforming the <code>discontinuous</code> value of the <loc
-href="#parameter-attribute-markerMode"><att>ttp:markerMode</att></loc>
-attribute.</p>
-<p>A TTML presentation processor supports the
-<code>#markerMode-discontinuous</code> feature if it implements presentation semantic support
-for the <code>discontinuous</code> value of the <loc
-href="#parameter-attribute-markerMode"><att>ttp:markerMode</att></loc>
-attribute.</p>
-</div3>
-<div3 id="feature-metadata">
-<head>#metadata</head>
-<p>A TTML transformation processor supports the <code>#metadata</code>
-feature if it recognizes and is capable of transforming the following
-vocabulary defined by <specref ref="metadata"/>:</p>
-<ulist>
-<item><p><loc href="#metadata-vocabulary-metadata"><el>metadata</el></loc></p></item>
-<item><p><loc href="#metadata-vocabulary-title"><el>ttm:title</el></loc></p></item>
-<item><p><loc href="#metadata-vocabulary-title"><el>ttm:desc</el></loc></p></item>
-<item><p><loc href="#metadata-vocabulary-title"><el>ttm:copyright</el></loc></p></item>
-<item><p><loc href="#metadata-vocabulary-title"><el>ttm:agent</el></loc></p></item>
-<item><p><loc href="#metadata-vocabulary-title"><el>ttm:name</el></loc></p></item>
-<item><p><loc href="#metadata-vocabulary-title"><el>ttm:actor</el></loc></p></item>
-<item><p><loc href="#metadata-attribute-agent">@<att>ttm:agent</att></loc></p></item>
-<item><p><loc href="#metadata-attribute-role">@<att>ttm:role</att></loc></p></item>
-</ulist>
-<p>A TTML presentation processor supports the <code>#metadata</code>
-feature if it recognizes and is capable of presenting the information
-expressed by the same vocabulary enumerated above.</p>
-<note role="clarification">
-<p>This specification does not define a standardized form for the
-presentation of metadata information. The presentation or ability to
-present metadata information is considered to be implementation
-dependent.</p>
-</note>
-</div3>
-<div3 id="feature-nested-div">
-<head>#nested-div</head>
-<p>A TTML transformation processor supports the <code>#nested-div</code>
-feature if it recognizes and is capable of transforming nested
-<loc href="#content-vocabulary-div"><el>div</el></loc> elements.</p>
-<p>A TTML presentation processor supports the <code>#nested-div</code>
-feature if it implements presentation semantic support for nested
-<loc href="#content-vocabulary-div"><el>div</el></loc> elements.</p>
-</div3>
-<div3 id="feature-nested-span">
-<head>#nested-span</head>
-<p>A TTML transformation processor supports the <code>#nested-span</code>
-feature if it recognizes and is capable of transforming nested
-<loc href="#content-vocabulary-span"><el>span</el></loc> elements.</p>
-<p>A TTML presentation processor supports the <code>#nested-span</code>
-feature if it implements presentation semantic support for nested
-<loc href="#content-vocabulary-span"><el>span</el></loc> elements.</p>
-</div3>
-<div3 id="feature-opacity">
-<head>#opacity</head>
-<p>A TTML transformation processor supports the
-<code>#opacity</code> feature if it recognizes and is capable of
-transforming the <loc
-href="#style-attribute-opacity"><att>tts:opacity</att></loc>
-attribute.</p>
-<p>A TTML presentation processor supports the
-<code>#opacity</code> feature if it (1) implements presentation semantic support for
-the <loc
-href="#style-attribute-opacity"><att>tts:opacity</att></loc>
-attribute and (2) is capable of displaying or generating an output display
-signal that distinguishes between at least eight (8) values of opacity.</p>
-</div3>
-<div3 id="feature-origin">
-<head>#origin</head>
-<p>A TTML transformation processor supports the
-<code>#origin</code> feature if it recognizes and is capable of
-transforming the <loc
-href="#style-attribute-origin"><att>tts:origin</att></loc>
-attribute.</p>
-<p>A TTML presentation processor supports the
-<code>#origin</code> feature if it implements presentation semantic support for
-the <loc
-href="#style-attribute-origin"><att>tts:origin</att></loc>
-attribute.</p>
-</div3>
-<div3 id="feature-overflow">
-<head>#overflow</head>
-<p>A TTML transformation processor supports the
-<code>#overflow</code> feature if it recognizes and is capable of
-transforming all defined values of the <loc
-href="#style-attribute-overflow"><att>tts:overflow</att></loc>
-attribute.</p>
-<p>A TTML presentation processor supports the
-<code>#overflow</code> feature if it implements presentation semantic support for
-all defined values of the <loc
-href="#style-attribute-overflow"><att>tts:overflow</att></loc>
-attribute.</p>
-</div3>
-<div3 id="feature-overflow-visible">
-<head>#overflow-visible</head>
-<p>A TTML transformation processor supports the
-<code>#overflow-visible</code> feature if it recognizes and is capable of
-transforming the <code>visible</code> value of the <loc
-href="#style-attribute-overflow"><att>tts:overflow</att></loc>
-attribute.</p>
-<p>A TTML presentation processor supports the
-<code>#overflow-visible</code> feature if it implements presentation semantic support for
-the <code>visible</code> value of the <loc
-href="#style-attribute-overflow"><att>tts:overflow</att></loc>
-attribute.</p>
-</div3>
-<div3 id="feature-padding">
-<head>#padding</head>
-<p>A TTML transformation processor supports the
-<code>#padding</code> feature if it recognizes and is capable of
-transforming the <loc
-href="#style-attribute-padding"><att>tts:padding</att></loc>
-attribute.</p>
-<p>A TTML presentation processor supports the
-<code>#padding</code> feature if it implements presentation semantic support for
-the <loc
-href="#style-attribute-padding"><att>tts:padding</att></loc>
-attribute.</p>
-</div3>
-<div3 id="feature-padding-1">
-<head>#padding-1</head>
-<p>A TTML transformation processor supports the
-<code>#padding-1</code> feature if it recognizes and is capable of
-transforming values of the <loc
-href="#style-attribute-padding"><att>tts:padding</att></loc> attribute
-that consist of one <loc
-href="#style-value-length">&lt;length&gt;</loc> specification.</p>
-<p>A TTML presentation processor supports the <code>#padding-1</code>
-feature if it implements presentation semantic support for values of the <loc
-href="#style-attribute-padding"><att>tts:padding</att></loc> attribute
-that consist of one <loc
-href="#style-value-length">&lt;length&gt;</loc> specification.</p>
-</div3>
-<div3 id="feature-padding-2">
-<head>#padding-2</head>
-<p>A TTML transformation processor supports the
-<code>#padding-2</code> feature if it recognizes and is capable of
-transforming values of the <loc
-href="#style-attribute-padding"><att>tts:padding</att></loc> attribute
-that consist of two <loc
-href="#style-value-length">&lt;length&gt;</loc> specification.</p>
-<p>A TTML presentation processor supports the <code>#padding-2</code>
-feature if it implements presentation semantic support for values of the <loc
-href="#style-attribute-padding"><att>tts:padding</att></loc> attribute
-that consist of two <loc
-href="#style-value-length">&lt;length&gt;</loc> specification.</p>
-</div3>
-<div3 id="feature-padding-3">
-<head>#padding-3</head>
-<p>A TTML transformation processor supports the
-<code>#padding-3</code> feature if it recognizes and is capable of
-transforming values of the <loc
-href="#style-attribute-padding"><att>tts:padding</att></loc> attribute
-that consist of three <loc
-href="#style-value-length">&lt;length&gt;</loc> specification.</p>
-<p>A TTML presentation processor supports the <code>#padding-3</code>
-feature if it implements presentation semantic support for values of the <loc
-href="#style-attribute-padding"><att>tts:padding</att></loc> attribute
-that consist of three <loc
-href="#style-value-length">&lt;length&gt;</loc> specification.</p>
-</div3>
-<div3 id="feature-padding-4">
-<head>#padding-4</head>
-<p>A TTML transformation processor supports the
-<code>#padding-4</code> feature if it recognizes and is capable of
-transforming values of the <loc
-href="#style-attribute-padding"><att>tts:padding</att></loc> attribute
-that consist of four <loc
-href="#style-value-length">&lt;length&gt;</loc> specification.</p>
-<p>A TTML presentation processor supports the <code>#padding-4</code>
-feature if it implements presentation semantic support for values of the <loc
-href="#style-attribute-padding"><att>tts:padding</att></loc> attribute
-that consist of four <loc
-href="#style-value-length">&lt;length&gt;</loc> specification.</p>
-</div3>
-<div3 id="feature-pixelAspectRatio">
-<head>#pixelAspectRatio</head>
-<p>A TTML transformation processor supports the
-<code>#pixelAspectRatio</code> feature if it recognizes and is capable of
-transforming the <loc
-href="#parameter-attribute-pixelAspectRatio"><att>ttp:pixelAspectRatio</att></loc>
-attribute.</p>
-<p>A TTML presentation processor supports the
-<code>#pixelAspectRatio</code> feature if it implements presentation semantic support
-for the <loc
-href="#parameter-attribute-pixelAspectRatio"><att>ttp:pixelAspectRatio</att></loc>
-attribute.</p>
-</div3>
-<div3 id="feature-presentation">
-<head>#presentation</head>
-<p>A TTML processor supports the
-<code>#presentation</code> feature if it
-(1) satisfies the generic processor criteria defined by 
-<specref ref="conformance-generic-processor"/>,
-(2) implements support for the region and line layout
-semantics defined by <specref ref="semantics-region-layout"/> and
-<specref ref="semantics-line-layout"/>, respectively, and
-(3) implements presentation semantics for the following features:</p>
-<ulist>
-<item><p><loc href="#content"><code>#content</code></loc></p></item>
-<item><p><loc href="#feature-core"><code>#core</code></loc></p></item>
-<item><p><loc href="#feature-profile"><code>#profile</code></loc></p></item>
-<item><p><loc href="#feature-structure"><code>#structure</code></loc></p></item>
-<item><p><loc href="#feature-time-offset"><code>#time-offset</code></loc></p></item>
-<item><p><loc href="#timing"><code>#timing</code></loc></p></item>
-</ulist>
-<p>
-In addition, a TTML processor that supports the
-<code>#presentation</code> feature should satisfy the user agent
-accessibility guidelines specified by <bibref ref="uaag"/>.</p>
-</div3>
-<div3 id="feature-profile">
-<head>#profile</head>
-<p>A TTML transformation processor supports the <code>#profile</code>
-feature if it recognizes and is capable of transforming the
-<loc href="#parameter-attribute-profile"><att>ttp:profile</att></loc>
-attribute on the <loc
-href="#document-structure-vocabulary-tt"><el>tt</el></loc> element and
-transforming the following vocabulary defined by
-<specref ref="parameter-element-vocabulary"/>:</p>
-<ulist>
-<item><p><loc
-href="#parameter-vocabulary-profile"><el>ttp:profile</el></loc></p></item>
-<item><p><loc
-href="#parameter-vocabulary-features"><el>ttp:features</el></loc></p></item>
-<item><p><loc
-href="#parameter-vocabulary-feature"><el>ttp:feature</el></loc></p></item>
-<item><p><loc
-href="#parameter-vocabulary-extensions"><el>ttp:extensions</el></loc></p></item>
-<item><p><loc
-href="#parameter-vocabulary-extension"><el>ttp:extension</el></loc></p></item>
-</ulist>
-<p>A TTML presentation processor supports the
-<code>#profile</code> feature if it implements presentation semantic support
-for the same vocabulary specified above.</p>
-</div3>
-<div3 id="feature-showBackground">
-<head>#showBackground</head>
-<p>A TTML transformation processor supports the
-<code>#showBackground</code> feature if it recognizes and is capable
-of transforming all defined values of the <loc
-href="#style-attribute-showBackground"><att>tts:showBackground</att></loc>
-attribute.</p>
-<p>A TTML presentation processor supports the
-<code>#showBackground</code> feature if it implements presentation semantic support
-for all defined values of the <loc
-href="#style-attribute-showBackground"><att>tts:showBackground</att></loc>
-attribute.</p>
-</div3>
-<div3 id="feature-structure">
-<head>#structure</head>
-<p>A TTML transformation processor supports the <code>#structure</code>
-feature if it recognizes and is capable of transforming the following
-vocabulary defined by <specref ref="content"/>:</p>
-<ulist>
-<item><p><loc href="#document-structure-vocabulary-tt"><el>tt</el></loc></p></item>
-<item><p><loc href="#document-structure-vocabulary-head"><el>head</el></loc></p></item>
-</ulist>
-<p>A TTML presentation processor supports the <code>#structure</code>
-feature if it implements presentation semantic support for the
-same vocabulary enumerated above.</p>
-</div3>
-<div3 id="feature-styling">
-<head>#styling</head>
-<p>A TTML transformation processor supports the <code>#styling</code>
-feature if it recognizes and is capable of transforming the following
-vocabulary defined by <specref ref="styling"/>:</p>
-<ulist>
-<item><p><loc href="#styling-vocabulary-styling"><el>styling</el></loc></p></item>
-<item><p><loc href="#styling-vocabulary-style"><el>style</el></loc></p></item>
-<item><p><loc href="#style-attribute-style">@<att>style</att></loc></p></item>
-</ulist>
-<p>A TTML presentation processor supports the <code>#styling</code>
-feature if it implements presentation semantic support for the
-same vocabulary enumerated above.</p>
-</div3>
-<div3 id="feature-styling-chained">
-<head>#styling-chained</head>
-<p>A TTML transformation processor supports the
-<code>#styling-chained</code> feature if it recognizes and is capable
-of transforming chained style association as defined by <specref
-ref="semantics-style-association-chained-referential"/>.</p>
-<p>A TTML presentation processor supports the
-<code>#styling-chained</code> feature if it implements presentation semantic
-support for chained style association as defined by <specref
-ref="semantics-style-association-chained-referential"/>.</p>
-</div3>
-<div3 id="feature-styling-inheritance-content">
-<head>#styling-inheritance-content</head>
-<p>A TTML transformation processor supports the
-<code>#styling-inheritance</code> feature if it recognizes and is
-capable of transforming content style inheritance as defined by
-<specref ref="semantics-style-inheritance-content"/>.</p>
-<p>A TTML presentation processor supports the
-<code>#styling-inheritance-content</code> feature if it implements
-presentation semantic support for content style inheritance as defined by <specref
-ref="semantics-style-inheritance-content"/>.</p>
-</div3>
-<div3 id="feature-styling-inheritance-region">
-<head>#styling-inheritance-region</head>
-<p>A TTML transformation processor supports the
-<code>#styling-inheritance</code> feature if it recognizes and is
-capable of transforming region style inheritance as defined by
-<specref ref="semantics-style-inheritance-region"/>.</p>
-<p>A TTML presentation processor supports the
-<code>#styling-inheritance-region</code> feature if it implements
-presentation semantic support for region style inheritance as defined by <specref
-ref="semantics-style-inheritance-region"/>.</p>
-</div3>
-<div3 id="feature-styling-inline">
-<head>#styling-inline</head>
-<p>A TTML transformation processor supports the
-<code>#styling-inline</code> feature if it recognizes and is capable
-of transforming inline style association as defined by <specref
-ref="semantics-style-association-inline"/>.</p>
-<p>A TTML presentation processor supports the
-<code>#styling-inline</code> feature if it implements presentation semantic support
-for inline style association as defined by <specref
-ref="semantics-style-association-inline"/>.</p>
-</div3>
-<div3 id="feature-styling-nested">
-<head>#styling-nested</head>
-<p>A TTML transformation processor supports the
-<code>#styling-nested</code> feature if it recognizes and is capable
-of transforming nested style association as defined by <specref
-ref="semantics-style-association-nested"/>.</p>
-<p>A TTML presentation processor supports the
-<code>#styling-nested</code> feature if it implements presentation semantic support
-for nested style association as defined by <specref
-ref="semantics-style-association-nested"/>.</p>
-</div3>
-<div3 id="feature-styling-referential">
-<head>#styling-referential</head>
-<p>A TTML transformation processor supports the
-<code>#styling-referential</code> feature if it recognizes and is capable
-of transforming referential style association as defined by <specref
-ref="semantics-style-association-referential"/>.</p>
-<p>A TTML presentation processor supports the
-<code>#styling-referential</code> feature if it implements presentation semantic
-support for referential style association as defined by <specref
-ref="semantics-style-association-referential"/>.</p>
-</div3>
-<div3 id="feature-subFrameRate">
-<head>#subFrameRate</head>
-<p>A TTML transformation processor supports the
-<code>#subFrameRate</code> feature if it recognizes and is capable of
-transforming the <loc
-href="#parameter-attribute-subFrameRate"><att>ttp:subFrameRate</att></loc>
-attribute.</p>
-<p>A TTML presentation processor supports the
-<code>#subFrameRate</code> feature if it implements presentation semantic support
-for the <loc
-href="#parameter-attribute-subFrameRate"><att>ttp:subFrameRate</att></loc>
-attribute.</p>
-</div3>
-<div3 id="feature-textAlign">
-<head>#textAlign</head>
-<p>A TTML transformation processor supports the
-<code>#textAlign</code> feature if it recognizes and is capable
-of transforming all defined values of the <loc
-href="#style-attribute-textAlign"><att>tts:textAlign</att></loc>
-attribute.</p>
-<p>A TTML presentation processor supports the
-<code>#textAlign</code> feature if it implements presentation semantic support
-for all defined values of the <loc
-href="#style-attribute-textAlign"><att>tts:textAlign</att></loc>
-attribute.</p>
-</div3>
-<div3 id="feature-textAlign-absolute">
-<head>#textAlign-absolute</head>
-<p>A TTML transformation processor supports the
-<code>#textAlign-absolute</code> feature if it recognizes and is
-capable of transforming the <code>left</code>, <code>center</code>,
-and <code>right</code> values of the <loc
-href="#style-attribute-textAlign"><att>tts:textAlign</att></loc>
-attribute.</p>
-<p>A TTML presentation processor supports the
-<code>#textAlign-absolute</code> feature if it implements presentation semantic
-support for the <code>left</code>, <code>center</code>, and
-<code>right</code> values of the <loc
-href="#style-attribute-textAlign"><att>tts:textAlign</att></loc>
-attribute.</p>
-</div3>
-<div3 id="feature-textAlign-relative">
-<head>#textAlign-relative</head>
-<p>A TTML transformation processor supports the
-<code>#textAlign-relative</code> feature if it recognizes and is
-capable of transforming the <code>start</code>, <code>center</code>,
-and <code>end</code> values of the <loc
-href="#style-attribute-textAlign"><att>tts:textAlign</att></loc>
-attribute.</p>
-<p>A TTML presentation processor supports the
-<code>#textAlign-relative</code> feature if it implements presentation semantic
-support for the <code>start</code>, <code>center</code>, and
-<code>end</code> values of the <loc
-href="#style-attribute-textAlign"><att>tts:textAlign</att></loc>
-attribute.</p>
-</div3>
-<div3 id="feature-textDecoration">
-<head>#textDecoration</head>
-<p>A TTML transformation processor supports the
-<code>#textDecoration</code> feature if it recognizes and is capable
-of transforming all defined values of the <loc
-href="#style-attribute-textDecoration"><att>tts:textDecoration</att></loc>
-attribute.</p>
-<p>A TTML presentation processor supports the
-<code>#textDecoration</code> feature if it implements presentation semantic support
-for all defined values of the <loc
-href="#style-attribute-textDecoration"><att>tts:textDecoration</att></loc>
-attribute.</p>
-</div3>
-<div3 id="feature-textDecoration-over">
-<head>#textDecoration-over</head>
-<p>A TTML transformation processor supports the
-<code>#textDecoration-over</code> feature if it recognizes and is
-capable of transforming the <code>overline</code> and
-<code>noOverline</code> values of the <loc
-href="#style-attribute-textDecoration"><att>tts:textDecoration</att></loc>
-attribute.</p>
-<p>A TTML presentation processor supports the
-<code>#textDecoration-over</code> feature if it implements
-presentation semantic support for the <code>overline</code> and
-<code>noOverline</code> values of the <loc
-href="#style-attribute-textDecoration"><att>tts:textDecoration</att></loc>
-attribute.</p>
-</div3>
-<div3 id="feature-textDecoration-through">
-<head>#textDecoration-through</head>
-<p>A TTML transformation processor supports the
-<code>#textDecoration-through</code> feature if it recognizes and is
-capable of transforming the <code>lineThrough</code> and
-<code>noLineThrough</code> values of the <loc
-href="#style-attribute-textDecoration"><att>tts:textDecoration</att></loc>
-attribute.</p>
-<p>A TTML presentation processor supports the
-<code>#textDecoration-through</code> feature if it implements
-presentation semantic support for the <code>lineThrough</code> and
-<code>noLineThrough</code> values of the <loc
-href="#style-attribute-textDecoration"><att>tts:textDecoration</att></loc>
-attribute.</p>
-</div3>
-<div3 id="feature-textDecoration-under">
-<head>#textDecoration-under</head>
-<p>A TTML transformation processor supports the
-<code>#textDecoration-under</code> feature if it recognizes and is
-capable of transforming the <code>underline</code> and
-<code>noUnderline</code> values of the <loc
-href="#style-attribute-textDecoration"><att>tts:textDecoration</att></loc>
-attribute.</p>
-<p>A TTML presentation processor supports the
-<code>#textDecoration-under</code> feature if it implements
-presentation semantic support for the <code>underline</code> and
-<code>noUnderline</code> values of the <loc
-href="#style-attribute-textDecoration"><att>tts:textDecoration</att></loc>
-attribute.</p>
-</div3>
-<div3 id="feature-textOutline">
-<head>#textOutline</head>
-<p>A TTML transformation processor supports the
-<code>#textOutline</code> feature if it recognizes and is capable of
-transforming the <loc
-href="#style-attribute-textOutline"><att>tts:textOutline</att></loc>
-attribute.</p>
-<p>A TTML presentation processor supports the
-<code>#textOutline</code> feature if it implements presentation semantic support
-for the <loc
-href="#style-attribute-textOutline"><att>tts:textOutline</att></loc>
-attribute.</p>
-</div3>
-<div3 id="feature-textOutline-blurred">
-<head>#textOutline-blurred</head>
-<p>A TTML transformation processor supports the
-<code>#textOutline-blurred</code> feature if it recognizes and is capable of
-transforming values of the <loc
-href="#style-attribute-textOutline"><att>tts:textOutline</att></loc>
-attribute that includes a blur radius specification.</p>
-<p>A TTML presentation processor supports the
-<code>#textOutline-blurred</code> feature if it implements presentation semantic support
-for values of the <loc
-href="#style-attribute-textOutline"><att>tts:textOutline</att></loc>
-attribute that includes a blur radius specification.</p>
-</div3>
-<div3 id="feature-textOutline-unblurred">
-<head>#textOutline-unblurred</head>
-<p>A TTML transformation processor supports the
-<code>#textOutline-unblurred</code> feature if it recognizes and is capable of
-transforming values of the <loc
-href="#style-attribute-textOutline"><att>tts:textOutline</att></loc>
-attribute that does not include a blur radius specification.</p>
-<p>A TTML presentation processor supports the
-<code>#textOutline-unblurred</code> feature if it implements presentation semantic support
-for values of the <loc
-href="#style-attribute-textOutline"><att>tts:textOutline</att></loc>
-attribute that does not include a blur radius specification.</p>
-</div3>
-<div3 id="feature-tickRate">
-<head>#tickRate</head>
-<p>A TTML transformation processor supports the
-<code>#tickRate</code> feature if it recognizes and is capable of
-transforming the <loc
-href="#parameter-attribute-tickRate"><att>ttp:tickRate</att></loc>
-attribute.</p>
-<p>A TTML presentation processor supports the
-<code>#tickRate</code> feature if it implements presentation semantic support
-for the <loc
-href="#parameter-attribute-tickRate"><att>ttp:tickRate</att></loc>
-attribute.</p>
-</div3>
-<div3 id="feature-timeBase-clock">
-<head>#timeBase-clock</head>
-<p>A TTML transformation processor supports the
-<code>#timeBase-clock</code> feature if it recognizes and is capable
-of transforming the <code>clock</code> value of the <loc
-href="#parameter-attribute-timeBase"><att>ttp:timeBase</att></loc>
-attribute and if it supports the <loc
-href="#feature-clockMode"><code>#clockMode</code></loc> feature.</p>
-<p>A TTML presentation processor supports the
-<code>#timeBase-clock</code> feature if it implements presentation
-semantic support for the <code>clock</code> value of the <loc
-href="#parameter-attribute-timeBase"><att>ttp:timeBase</att></loc>
-attribute and if it supports the <loc
-href="#feature-clockMode"><code>#clockMode</code></loc> feature.</p>
-</div3>
-<div3 id="feature-timeBase-media">
-<head>#timeBase-media</head>
-<p>A TTML transformation processor supports the
-<code>#timeBase-media</code> feature if it recognizes and is capable
-of transforming the <code>media</code> value of the <loc
-href="#parameter-attribute-timeBase"><att>ttp:timeBase</att></loc>
-attribute.</p>
-<p>A TTML presentation processor supports the
-<code>#timeBase-media</code> feature if it implements presentation
-semantic support for the <code>media</code> value of the <loc
-href="#parameter-attribute-timeBase"><att>ttp:timeBase</att></loc>
-attribute.</p>
-</div3>
-<div3 id="feature-timeBase-smpte">
-<head>#timeBase-smpte</head>
-<p>A TTML transformation processor supports the
-<code>#timeBase-smpte</code> feature if it recognizes and is capable
-of transforming the <code>smpte</code> value of the <loc
-href="#parameter-attribute-timeBase"><att>ttp:timeBase</att></loc>
-attribute and if it supports the <loc
-href="#feature-dropMode"><code>#dropMode</code></loc> feature.</p>
-<p>A TTML presentation processor supports the
-<code>#timeBase-smpte</code> feature if it implements presentation
-semantic support for the <code>smpte</code> value of the <loc
-href="#parameter-attribute-timeBase"><att>ttp:timeBase</att></loc>
-attribute and if it supports the <loc
-href="#feature-dropMode"><code>#dropMode</code></loc> feature.</p>
-</div3>
-<div3 id="feature-timeContainer">
-<head>#timeContainer</head>
-<p>A TTML transformation processor supports the
-<code>#timeContainer</code> feature if it recognizes and is capable of
-transforming the <loc
-href="#timing-attribute-timeContainer"><att>timeContainer</att></loc>
-attribute.</p>
-<p>A TTML presentation processor supports the
-<code>#timeContainer</code> feature if it implements presentation semantic support
-for the <loc
-href="#timing-attribute-timeContainer"><att>timeContainer</att></loc>
-attribute.</p>
-</div3>
-<div3 id="feature-time-clock">
-<head>#time-clock</head>
-<p>A TTML transformation processor supports the
-<code>#time-clock</code> feature if it recognizes and is capable of
-transforming all values of the <loc
-href="#timing-value-timeExpression">&lt;timeExpression&gt;</loc> that
-satisfy the following subset of time expression syntax:</p>
-<eg xml:space="preserve">
-&lt;timeExpression&gt;
-  : hours ":" minutes ":" seconds ( fraction )?
-</eg>
-<p>A TTML presentation processor supports the
-<code>#time-clock</code> feature if it implements presentation
-semantic support for the same syntax specified above.</p>
-</div3>
-<div3 id="feature-time-clock-with-frames">
-<head>#time-clock-with-frames</head>
-<p>A TTML transformation processor supports the
-<code>#time-clock-with-frames</code> feature if it supports the
-<loc href="#feature-frameRate"><code>#frameRate</code></loc>,
-<loc href="#feature-frameRateMultiplier"><code>#frameRateMultiplier</code></loc>, and
-<loc href="#feature-subFrameRate"><code>#subFrameRate</code></loc> features
-and if it recognizes and is capable of
-transforming all values of the <loc
-href="#timing-value-timeExpression">&lt;timeExpression&gt;</loc> that
-satisfy the following subset of time expression syntax:</p>
-<eg xml:space="preserve">
-&lt;timeExpression&gt;
-  : hours ":" minutes ":" seconds ( fraction | ":" frames ( "." sub-frames )? )?
-</eg>
-<p>A TTML presentation processor supports the
-<code>#time-clock-with-frames</code> feature if it implements
-presentation semantic support for the same features and syntax
-specified above.</p>
-</div3>
-<div3 id="feature-time-offset">
-<head>#time-offset</head>
-<p>A TTML transformation processor supports the
-<code>#time-offset</code> feature if it recognizes and is capable of
-transforming all values of the <loc
-href="#timing-value-timeExpression">&lt;timeExpression&gt;</loc> that
-satisfy the following subset of time expression syntax:</p>
-<eg xml:space="preserve">
-&lt;timeExpression&gt;
-  : time-count fraction? ( "h" | "m" | "s" | "ms" )
-</eg>
-<p>A TTML presentation processor supports the
-<code>#time-offset</code> feature if it implements presentation
-semantic support for the same syntax specified above.</p>
-</div3>
-<div3 id="feature-time-offset-with-frames">
-<head>#time-offset-with-frames</head>
-<p>A TTML transformation processor supports the
-<code>#time-offset-with-frames</code> feature if it supports the
-<loc href="#feature-frameRate"><code>#frameRate</code></loc>,
-<loc href="#feature-frameRateMultiplier"><code>#frameRateMultiplier</code></loc>, and
-<loc href="#feature-subFrameRate"><code>#subFrameRate</code></loc> features
-and if it recognizes and is capable of
-transforming all values of the <loc
-href="#timing-value-timeExpression">&lt;timeExpression&gt;</loc> that
-satisfy the following subset of time expression syntax:</p>
-<eg xml:space="preserve">
-&lt;timeExpression&gt;
-  : time-count fraction? "f"
-</eg>
-<p>A TTML presentation processor supports the
-<code>#time-offset-with-frames</code> feature if it implements
-presentation semantic support for the same features and syntax
-specified above.</p>
-</div3>
-<div3 id="feature-time-offset-with-ticks">
-<head>#time-offset-with-ticks</head>
-<p>A TTML transformation processor supports the
-<code>#time-offset-with-ticks</code> feature if it supports the 
-<loc href="#feature-tickRate"><code>#tickRate</code></loc> feature
-and if it recognizes and is capable of
-transforming all values of the <loc
-href="#timing-value-timeExpression">&lt;timeExpression&gt;</loc> that
-satisfy the following subset of time expression syntax:</p>
-<eg xml:space="preserve">
-&lt;timeExpression&gt;
-  : time-count fraction? "t"
-</eg>
-<p>A TTML presentation processor supports the
-<code>#time-offset-with-ticks</code> feature if it implements presentation
-semantic support for the same features and syntax specified above.</p>
-</div3>
-<div3 id="feature-timing">
-<head>#timing</head>
-<p>A TTML transformation processor supports the <code>#timing</code>
-feature if it recognizes and is capable of transforming the following
-vocabulary defined by <specref ref="timing"/>:</p>
-<ulist>
-<item><p><loc href="#timing-attribute-begin">@<att>begin</att></loc></p></item>
-<item><p><loc href="#timing-attribute-dur">@<att>dur</att></loc></p></item>
-<item><p><loc href="#timing-attribute-end">@<att>end</att></loc></p></item>
-</ulist>
-<p>A TTML presentation processor supports the <code>#timing</code>
-feature if it implements presentation semantic support for the
-same vocabulary enumerated above.</p>
-</div3>
-<div3 id="feature-transformation">
-<head>#transformation</head>
-<p>A TTML processor supports the
-<code>#transformation</code> feature if it
-(1) satisfies the generic processor criteria defined by 
-<specref ref="conformance-generic-processor"/> and
-(2) implements the transformation semantics of the following features:</p>
-<ulist>
-<item><p><loc href="#content"><code>#content</code></loc></p></item>
-<item><p><loc href="#feature-core"><code>#core</code></loc></p></item>
-<item><p><loc href="#feature-profile"><code>#profile</code></loc></p></item>
-<item><p><loc href="#feature-structure"><code>#structure</code></loc></p></item>
-<item><p><loc href="#feature-time-offset"><code>#time-offset</code></loc></p></item>
-<item><p><loc href="#timing"><code>#timing</code></loc></p></item>
-</ulist>
-</div3>
-<div3 id="feature-unicodeBidi">
-<head>#unicodeBidi</head>
-<p>A TTML transformation processor supports the
-<code>#unicodeBidi</code> feature if it recognizes and is capable of
-transforming all defined values of the <loc
-href="#style-attribute-unicodeBidi"><att>tts:unicodeBidi</att></loc>
-attribute.</p>
-<p>A TTML presentation processor supports the
-<code>#unicodeBidi</code> feature if it implements presentation semantic support
-for all defined values of the <loc
-href="#style-attribute-unicodeBidi"><att>tts:unicodeBidi</att></loc>
-attribute.</p>
-</div3>
-<div3 id="feature-visibility">
-<head>#visibility</head>
-<p>A TTML transformation processor supports the
-<code>#visibility</code> feature if it recognizes and is capable
-of transforming all defined values of the <loc
-href="#style-attribute-visibility"><att>tts:visibility</att></loc>
-attribute.</p>
-<p>A TTML presentation processor supports the
-<code>#visibility</code> feature if it implements presentation semantic support
-for all defined values of the <loc
-href="#style-attribute-visibility"><att>tts:visibility</att></loc>
-attribute.</p>
-</div3>
-<div3 id="feature-visibility-block">
-<head>#visibility-block</head>
-<p>A TTML transformation processor supports the
-<code>#visibility-block</code> feature if it recognizes and is
-capable of transforming all defined values of the <loc
-href="#style-attribute-visibility"><att>tts:visibility</att></loc>
-attribute when applied to a content element that would generate a
-block area during presentation processing.</p>
-<p>A TTML presentation processor supports the
-<code>#visibility-block</code> feature if it implements presentation semantic
-support for all defined values of the <loc
-href="#style-attribute-visibility"><att>tts:visibility</att></loc>
-attribute when applied to a content element that generates a
-block area.</p>
-</div3>
-<div3 id="feature-visibility-inline">
-<head>#visibility-inline</head>
-<p>A TTML transformation processor supports the
-<code>#visibility-inline</code> feature if it recognizes and is
-capable of transforming all defined values of the <loc
-href="#style-attribute-visibility"><att>tts:visibility</att></loc>
-attribute when applied to a content element that would generate an
-inline area during presentation processing.</p>
-<p>A TTML presentation processor supports the
-<code>#visibility-inline</code> feature if it implements presentation semantic
-support for all defined values of the <loc
-href="#style-attribute-visibility"><att>tts:visibility</att></loc>
-attribute when applied to a content element that generates an
-inline area.</p>
-</div3>
-<div3 id="feature-visibility-region">
-<head>#visibility-region</head>
-<p>A TTML transformation processor supports the
-<code>#visibility-region</code> feature if it recognizes and is
-capable of transforming all defined values of the <loc
-href="#style-attribute-visibility"><att>tts:visibility</att></loc>
-attribute when applied to a <loc
-href="#layout-vocabulary-region"><el>region</el></loc> element.</p>
-<p>A TTML presentation processor supports the
-<code>#visibility-region</code> feature if it implements presentation semantic
-support for all defined values of the <loc
-href="#style-attribute-visibility"><att>tts:visibility</att></loc>
-attribute when applied to a <loc
-href="#layout-vocabulary-region"><el>region</el></loc> element.</p>
-</div3>
-<div3 id="feature-wrapOption">
-<head>#wrapOption</head>
-<p>A TTML transformation processor supports the
-<code>#wrapOption</code> feature if it recognizes and is capable
-of transforming all defined values of the <loc
-href="#style-attribute-wrapOption"><att>tts:wrapOption</att></loc>
-attribute.</p>
-<p>A TTML presentation processor supports the
-<code>#wrapOption</code> feature if it implements presentation semantic support
-for all defined values of the <loc
-href="#style-attribute-wrapOption"><att>tts:wrapOption</att></loc>
-attribute.</p>
-</div3>
-<div3 id="feature-writingMode">
-<head>#writingMode</head>
-<p>A TTML transformation processor supports the
-<code>#writingMode</code> feature if it recognizes and is capable
-of transforming all defined values of the <loc
-href="#style-attribute-writingMode"><att>tts:writingMode</att></loc>
-attribute.</p>
-<p>A TTML presentation processor supports the
-<code>#writingMode</code> feature if it implements presentation semantic support
-for all defined values of the <loc
-href="#style-attribute-writingMode"><att>tts:writingMode</att></loc>
-attribute.</p>
-</div3>
-<div3 id="feature-writingMode-vertical">
-<head>#writingMode-vertical</head>
-<p>A TTML transformation processor supports the
-<code>#writingMode-vertical</code> feature if it recognizes and is
-capable of transforming the <code>tbrl</code>, <code>tblr</code>, and
-<code>tb</code> values of the <loc
-href="#style-attribute-writingMode"><att>tts:writingMode</att></loc>
-attribute.</p>
-<p>A TTML presentation processor supports the
-<code>#writingMode-vertical</code> feature if it implements presentation semantic
-support for the <code>tbrl</code>, <code>tblr</code>, and
-<code>tb</code> values of the <loc
-href="#style-attribute-writingMode"><att>tts:writingMode</att></loc>
-attribute.</p>
-</div3>
-<div3 id="feature-writingMode-horizontal">
-<head>#writingMode-horizontal</head>
-<p>A TTML transformation processor supports the
-<code>#writingMode-horizontal</code> feature if it recognizes and is
-capable of transforming the <code>lrtb</code>, <code>rltb</code>,
-<code>lr</code> and <code>rl</code> values of the <loc
-href="#style-attribute-writingMode"><att>tts:writingMode</att></loc>
-attribute.</p>
-<p>A TTML presentation processor supports the
-<code>#writingMode-horizontal</code> feature if it implements presentation semantic
-support for the <code>lrtb</code>, <code>rltb</code>, <code>lr</code>
-and <code>rl</code> values of the <loc
-href="#style-attribute-writingMode"><att>tts:writingMode</att></loc>
-attribute.</p>
-</div3>
-<div3 id="feature-writingMode-horizontal-lr">
-<head>#writingMode-horizontal-lr</head>
-<p>A TTML transformation processor supports the
-<code>#writingMode-horizontal</code> feature if it recognizes and is
-capable of transforming the <code>lrtb</code> and <code>lr</code>
-values of the <loc
-href="#style-attribute-writingMode"><att>tts:writingMode</att></loc>
-attribute.</p>
-<p>A TTML presentation processor supports the
-<code>#writingMode-horizontal-lr</code> feature if it implements presentation semantic
-support for the <code>lrtb</code> and <code>lr</code> values of the
-<loc
-href="#style-attribute-writingMode"><att>tts:writingMode</att></loc>
-attribute.</p>
-</div3>
-<div3 id="feature-writingMode-horizontal-rl">
-<head>#writingMode-horizontal-rl</head>
-<p>A TTML transformation processor supports the
-<code>#writingMode-horizontal</code> feature if it recognizes and is
-capable of transforming the <code>rltb</code> and <code>rl</code>
-values of the <loc
-href="#style-attribute-writingMode"><att>tts:writingMode</att></loc>
-attribute.</p>
-<p>A TTML presentation processor supports the
-<code>#writingMode-horizontal-rl</code> feature if it implements presentation semantic
-support for the <code>rltb</code> and <code>rl</code> values of the
-<loc
-href="#style-attribute-writingMode"><att>tts:writingMode</att></loc>
-attribute.</p>
-</div3>
-<div3 id="feature-zIndex">
-<head>#zIndex</head>
-<p>A TTML transformation processor supports the
-<code>#zIndex</code> feature if it recognizes and is capable of
-transforming the <loc
-href="#style-attribute-zIndex"><att>tts:zIndex</att></loc>
-attribute.</p>
-<p>A TTML presentation processor supports the
-<code>#zIndex</code> feature if it implements presentation semantic support for
-the <loc
-href="#style-attribute-zIndex"><att>tts:zIndex</att></loc>
-attribute.</p>
-</div3>
-</div2>
-<div2 id="feature-support">
-<head>Feature Support</head>
-<p>The following table, <specref ref="feature-support-table"/>,
-enumerates every defined feature designation (expressed without the TT
-Feature Namespace), and, for each designated feature, specifies
-whether the feature is mandatory (M) or optional (O) for
-transformation and presentation processors.</p>
-<table id="feature-support-table" role="common">
-<caption>Table E-1 &ndash; Feature Support</caption>
-<col width="60%"/>
-<col width="20%"/>
-<col width="20%"/>
-<tbody>
-<tr>
-<td><phrase role="strong">Feature</phrase></td>
-<td><phrase role="strong">Transformation</phrase></td>
-<td><phrase role="strong">Presentation</phrase></td>
-</tr>
-<tr>
-<td><loc href="#feature-animation"><code>#animation</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-backgroundColor"><code>#backgroundColor</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-backgroundColor-block"><code>#backgroundColor-block</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-backgroundColor-inline"><code>#backgroundColor-inline</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-backgroundColor-region"><code>#backgroundColor-region</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-bidi"><code>#bidi</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-cellResolution"><code>#cellResolution</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-clockMode"><code>#clockMode</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-clockMode-gps"><code>#clockMode-gps</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-clockMode-local"><code>#clockMode-local</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-clockMode-utc"><code>#clockMode-utc</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-color"><code>#color</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-content"><code>#content</code></loc></td>
-<td>M</td>
-<td>M</td>
-</tr>
-<tr>
-<td><loc href="#feature-core"><code>#core</code></loc></td>
-<td>M</td>
-<td>M</td>
-</tr>
-<tr>
-<td><loc href="#feature-direction"><code>#direction</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-display"><code>#display</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-display-block"><code>#display-block</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-display-inline"><code>#display-inline</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-display-region"><code>#display-region</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-displayAlign"><code>#displayAlign</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-dropMode"><code>#dropMode</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-dropMode-dropNTSC"><code>#dropMode-dropNTSC</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-dropMode-dropPAL"><code>#dropMode-dropPAL</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-dropMode-nonDrop"><code>#dropMode-nonDrop</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-extent"><code>#extent</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-extent-region"><code>#extent-region</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-extent-root"><code>#extent-root</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-fontFamily"><code>#fontFamily</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-fontFamily-generic"><code>#fontFamily-generic</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-fontFamily-non-generic"><code>#fontFamily-non-generic</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-fontSize"><code>#fontSize</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-fontSize-anamorphic"><code>#fontSize-anamorphic</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-fontSize-isomorphic"><code>#fontSize-isomorphic</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-fontStyle"><code>#fontStyle</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-fontStyle-italic"><code>#fontStyle-italic</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-fontStyle-oblique"><code>#fontStyle-oblique</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-fontWeight"><code>#fontWeight</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-fontWeight-bold"><code>#fontWeight-bold</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-frameRate"><code>#frameRate</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-frameRateMultiplier"><code>#frameRateMultiplier</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-layout"><code>#layout</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-length"><code>#length</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-length-cell"><code>#length-cell</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-length-em"><code>#length-em</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-length-integer"><code>#length-integer</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-length-negative"><code>#length-negative</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-length-percentage"><code>#length-percentage</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-length-pixel"><code>#length-pixel</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-length-positive"><code>#length-positive</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-length-real"><code>#length-real</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-lineBreak-uax14"><code>#lineBreak-uax14</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-lineHeight"><code>#lineHeight</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-markerMode"><code>#markerMode</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-markerMode-continuous"><code>#markerMode-continuous</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-markerMode-discontinuous"><code>#markerMode-discontinuous</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-metadata"><code>#metadata</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-nested-div"><code>#nested-div</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-nested-span"><code>#nested-span</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-opacity"><code>#opacity</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-origin"><code>#origin</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-overflow"><code>#overflow</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-overflow-visible"><code>#overflow-visible</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-padding"><code>#padding</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-padding-1"><code>#padding-1</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-padding-2"><code>#padding-2</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-padding-3"><code>#padding-3</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-padding-4"><code>#padding-4</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-pixelAspectRatio"><code>#pixelAspectRatio</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-presentation"><code>#presentation</code></loc></td>
-<td>O</td>
-<td>M</td>
-</tr>
-<tr>
-<td><loc href="#feature-profile"><code>#profile</code></loc></td>
-<td>M</td>
-<td>M</td>
-</tr>
-<tr>
-<td><loc href="#feature-showBackground"><code>#showBackground</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-structure"><code>#structure</code></loc></td>
-<td>M</td>
-<td>M</td>
-</tr>
-<tr>
-<td><loc href="#feature-styling"><code>#styling</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-styling-chained"><code>#styling-chained</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-styling-inheritance-content"><code>#styling-inheritance-content</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-styling-inheritance-region"><code>#styling-inheritance-region</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-styling-inline"><code>#styling-inline</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-styling-nested"><code>#styling-nested</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-styling-referential"><code>#styling-referential</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-subFrameRate"><code>#subFrameRate</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-textAlign"><code>#textAlign</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-textAlign-absolute"><code>#textAlign-absolute</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-textAlign-relative"><code>#textAlign-relative</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-textDecoration"><code>#textDecoration</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-textDecoration-over"><code>#textDecoration-over</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-textDecoration-through"><code>#textDecoration-through</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-textDecoration-under"><code>#textDecoration-under</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-textOutline"><code>#textOutline</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-textOutline-blurred"><code>#textOutline-blurred</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-textOutline-unblurred"><code>#textOutline-unblurred</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-tickRate"><code>#tickRate</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-timeBase-clock"><code>#timeBase-clock</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-timeBase-media"><code>#timeBase-media</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-timeBase-smpte"><code>#timeBase-smpte</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-timeContainer"><code>#timeContainer</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-time-clock"><code>#time-clock</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-time-clock-with-frames"><code>#time-clock-with-frames</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-time-offset"><code>#time-offset</code></loc></td>
-<td>M</td>
-<td>M</td>
-</tr>
-<tr>
-<td><loc href="#feature-time-offset-with-frames"><code>#time-offset-with-frames</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-time-offset-with-ticks"><code>#time-offset-with-ticks</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-timing"><code>#timing</code></loc></td>
-<td>M</td>
-<td>M</td>
-</tr>
-<tr>
-<td><loc href="#feature-transformation"><code>#transformation</code></loc></td>
-<td>M</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-unicodeBidi"><code>#unicodeBidi</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-visibility"><code>#visibility</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-visibility-block"><code>#visibility-block</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-visibility-inline"><code>#visibility-inline</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-visibility-region"><code>#visibility-region</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-wrapOption"><code>#wrapOption</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-writingMode"><code>#writingMode</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-writingMode-vertical"><code>#writingMode-vertical</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-writingMode-horizontal"><code>#writingMode-horizontal</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-writingMode-horizontal-lr"><code>#writingMode-horizontal-lr</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-writingMode-horizontal-rl"><code>#writingMode-horizontal-rl</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-<tr>
-<td><loc href="#feature-zIndex"><code>#zIndex</code></loc></td>
-<td>O</td>
-<td>O</td>
-</tr>
-</tbody>
-</table>
-<p>For the sake of convenience, the following table,
-<specref ref="feature-transformation-mandatory-table"/>, enumerates all
-mandatory features for a TTML Transformation Processor, providing additional
-comments to summarize the context of usage or the nature of the feature.
-The TTML Profile Definition Document that defines the corresponding
-DFXP Transformation Profile is specified in
-<specref ref="profile-dfxp-transformation"/>.
-</p>
-<table id="feature-transformation-mandatory-table" role="common">
-<caption>Table E-2 &ndash; Mandatory Features - Transformation</caption>
-<col width="60%"/>
-<col width="40%"/>
-<tbody>
-<tr>
-<td><phrase role="strong">Feature</phrase></td>
-<td><phrase role="strong">Comments</phrase></td>
-</tr>
-<tr>
-<td><loc href="#feature-content"><code>#content</code></loc></td>
-<td>
-<loc href="#document-structure-vocabulary-body"><el>body</el></loc>,
-<loc href="#content-vocabulary-div"><el>div</el></loc>,
-<loc href="#content-vocabulary-p"><el>p</el></loc>,
-<loc href="#content-vocabulary-span"><el>span</el></loc>,
-<loc href="#content-vocabulary-br"><el>br</el></loc>
-</td>
-</tr>
-<tr>
-<td><loc href="#feature-core"><code>#core</code></loc></td>
-<td>
-<loc href="#content-attribute-id">@<att>xml:id</att></loc>,
-<loc href="#content-attribute-id">@<att>xml:lang</att></loc>,
-<loc href="#content-attribute-id">@<att>xml:space</att></loc>
-</td>
-</tr>
-<tr>
-<td><loc href="#feature-profile"><code>#profile</code></loc></td>
-<td></td>
-</tr>
-<tr>
-<td><loc href="#feature-structure"><code>#structure</code></loc></td>
-<td>
-<loc href="#document-structure-vocabulary-tt"><el>tt</el></loc>,
-<loc href="#document-structure-vocabulary-head"><el>head</el></loc>
-</td>
-</tr>
-
-<tr>
-<td><loc href="#feature-time-offset"><code>#time-offset</code></loc></td>
-<td></td>
-</tr>
-<tr>
-<td><loc href="#feature-timing"><code>#timing</code></loc></td>
-<td>
-<loc href="#timing-attribute-begin">@<att>begin</att></loc>,
-<loc href="#timing-attribute-dur">@<att>dur</att></loc>,
-<loc href="#timing-attribute-end">@<att>end</att></loc>
-</td>
-</tr>
-<tr>
-<td><loc href="#feature-transformation"><code>#transformation</code></loc></td>
-<td></td>
-</tr>
-</tbody>
-</table>
-<p>For the sake of convenience, the following table,
-<specref ref="feature-presentation-mandatory-table"/>, enumerates all
-mandatory features for a TTML Presentation Processor, providing additional
-comments to summarize the context of usage or the nature of the feature.
-The TTML Profile Definition Document that defines the corresponding
-DFXP Presentation Profile is specified in
-<specref ref="profile-dfxp-presentation"/>.
-</p>
-<table id="feature-presentation-mandatory-table" role="common">
-<caption>Table E-3 &ndash; Mandatory Features - Presentation</caption>
-<col width="60%"/>
-<col width="40%"/>
-<tbody>
-<tr>
-<td><phrase role="strong">Feature</phrase></td>
-<td><phrase role="strong">Comments</phrase></td>
-</tr>
-<tr>
-<td><loc href="#feature-content"><code>#content</code></loc></td>
-<td>
-<loc href="#document-structure-vocabulary-body"><el>body</el></loc>,
-<loc href="#content-vocabulary-div"><el>div</el></loc>,
-<loc href="#content-vocabulary-p"><el>p</el></loc>,
-<loc href="#content-vocabulary-span"><el>span</el></loc>,
-<loc href="#content-vocabulary-br"><el>br</el></loc>
-</td>
-</tr>
-<tr>
-<td><loc href="#feature-core"><code>#core</code></loc></td>
-<td>
-<loc href="#content-attribute-id">@<att>xml:id</att></loc>,
-<loc href="#content-attribute-id">@<att>xml:lang</att></loc>,
-<loc href="#content-attribute-id">@<att>xml:space</att></loc>
-</td>
-</tr>
-<tr>
-<td><loc href="#feature-profile"><code>#profile</code></loc></td>
-<td></td>
-</tr>
-<tr>
-<td><loc href="#feature-presentation"><code>#presentation</code></loc></td>
-<td></td>
-</tr>
-<tr>
-<td><loc href="#feature-structure"><code>#structure</code></loc></td>
-<td>
-<loc href="#document-structure-vocabulary-tt"><el>tt</el></loc>,
-<loc href="#document-structure-vocabulary-head"><el>head</el></loc>
-</td>
-</tr>
-<tr>
-<td><loc href="#feature-time-offset"><code>#time-offset</code></loc></td>
-<td></td>
-</tr>
-<tr>
-<td><loc href="#feature-timing"><code>#timing</code></loc></td>
-<td>
-<loc href="#timing-attribute-begin">@<att>begin</att></loc>,
-<loc href="#timing-attribute-dur">@<att>dur</att></loc>,
-<loc href="#timing-attribute-end">@<att>end</att></loc>
-</td>
-</tr>
-</tbody>
-</table>
-</div2>
-</div1>
-<div1 id="extensions">
-<head>Extensions</head>
-<p><emph>This appendix is normative.</emph></p>
-<p>This appendix specifies the syntactic form of extension designations, which are
-used to express authorial intent regarding the support for extension
-mechanisms in a TTML processor.</p>
-<div2 id="extension-designations">
-<head>Extension Designations</head>
-<p>An extension designation is expressed as a string that adheres to the following
-form:</p>
-<eg xml:space="preserve">
-extension-designation
-  : extension-namespace designation
-
-extension-namespace
-  : <emph>TT Extension Namespace</emph>                  // http://www.w3.org/ns/ttml/extension/
-  | <emph>Other Extension Namespace</emph>               // expressed as an absolute URI
-
-designation
-  : "#" token-char+
-
-token-char
-  : { XML NameChar }                        // XML 1.1 Production [4a]
-</eg>
-<p>If the extension namespace of an extension designation is the TT
-Extension Namespace, then all values of the following
-<code>designation</code> token are reserved for future
-standardization.</p>
-<p>If the extension namespace of an extension designation is not the
-TT Extension Namespace, i.e., is an <emph>Other Extension Namespace</emph>,
-then the extension namespace must be expressed as an absolute URI
-capable of serving as a base URI used in combination with a
-<code>designation</code> token that takes the form of a fragment
-identifier.</p>
-</div2>
-</div1>
-<div1 id="profiles">
-<head>Profiles</head>
-<p><emph>This appendix is normative.</emph></p>
-<p>This appendix specifies the following standard TTML profiles:</p>
-<ulist>
-<item><p><specref ref="profile-dfxp-transformation"/></p></item>
-<item><p><specref ref="profile-dfxp-presentation"/></p></item>
-<item><p><specref ref="profile-dfxp-full"/></p></item>
-</ulist>
-<p>Each TTML profile is defined in terms of a TTML Profile Definition Document,
-which is expressed as an XML document wherein the root element adheres to
-<specref ref="parameter-vocabulary-profile"/>.</p>
-<div2 id="profile-dfxp-transformation">
-<head>DFXP Transformation Profile</head>
-<p>The DFXP Transformation Profile is intended to be used to
-express minimum compliance for transformation processing.</p>
-<eg xml:space="preserve">&profile-dfxp-transformation;</eg>
-</div2>
-<div2 id="profile-dfxp-presentation">
-<head>DFXP Presentation Profile</head>
-<p>The DFXP Presentation Profile is intended to be used to
-express minimum compliance for presentation processing.</p>
-<eg xml:space="preserve">&profile-dfxp-presentation;</eg>
-</div2>
-<div2 id="profile-dfxp-full">
-<head>DFXP Full Profile</head>
-<p>The DFXP Full Profile is intended to be used to
-express maximum compliance for both transformation and presentation processing.</p>
-<eg xml:space="preserve">&profile-dfxp-full;</eg>
-</div2>
-</div1>
-<div1 id="references">
-<head>References</head>
-<p><emph>This appendix is normative.</emph></p>
-<blist>
-<bibl id="css2" key="CSS2">Bert Bos et al.,
-<titleref
-href="http://www.w3.org/TR/1998/REC-CSS2-19980512/">Cascading
-Style Sheets, Level 2</titleref>, W3C Recommendation, 12
-May 1998. (See
-<xspecref href="http://www.w3.org/TR/1998/REC-CSS2-19980512/">http://www.w3.org/TR/1998/REC-CSS2-19980512/</xspecref>.)
-</bibl>
-<bibl id="gps" key="GPS">
-<titleref href="http://tycho.usno.navy.mil/gpsinfo.html">Global
-Positioning System</titleref>, US Naval Observatory.
-(See
-<xspecref href="http://tycho.usno.navy.mil/gpsinfo.html">http://tycho.usno.navy.mil/gpsinfo.html</xspecref>.)
-</bibl>
-<bibl id="mime-media" key="MIME">Ned Freed and Nathaniel Borenstein,  
-<titleref
-href="http://www.rfc-editor.org/rfc/rfc2046.txt">Multipurpose Internet
-Mail Extensions (MIME) Part Two: Media Types</titleref>,
-RFC 2046, November 1996, IETF.(See
-<xspecref href="http://www.rfc-editor.org/rfc/rfc2046.txt">http://www.rfc-editor.org/rfc/rfc2046.txt</xspecref>.)
-</bibl>
-<bibl id="rng" key="RELAX NG">ISO/IEC 19757-2,
-<titleref href="http://www.iso.org/">Information technology &ndash; Document
-Schema Definition Language (DSDL) &ndash; Part 2: Regular-grammar-based validation &ndash; RELAX NG</titleref>,
-International Organization for Standardization (ISO).
-</bibl>
-<bibl id="smil21" key="SMIL 2.1">Dick Bultermann, et al.,
-<titleref href="http://www.w3.org/TR/2005/REC-SMIL2-20051213/">Synchronized
-Multimedia Integration Language (SMIL 2.1)</titleref>,
-W3C Recommendation, 13 December 2005. (See
-<xspecref href="http://www.w3.org/TR/2005/REC-SMIL2-20051213/">http://www.w3.org/TR/2005/REC-SMIL2-20051213/</xspecref>.)
-</bibl>
-<bibl id="smpte12m" key="SMPTE 12M">ANSI/SMPTE 12M,
-<titleref href="http://www.smpte.org/">Television, Audio and Film &ndash;
-Time and Control Code</titleref>, SMPTE Standard.
-</bibl>
-<bibl id="srgb" key="SRGB">IEC 61966-2-1,
-<titleref
-href="http://www.iec.ch/">Multimedia
-systems and equipment &ndash; Colour measurement and management
-&ndash; Part 2-1: Colour management &ndash; Default RGB colour space
-&ndash; sRGB</titleref>, International Electrotechnical
-Commission (IEC).
-</bibl>
-<bibl id="uaag" key="UAAG">Ian Jacobs, Jon Gunderson, and Eric Hansen, Eds.,
-<titleref href="http://www.w3.org/TR/2002/REC-UAAG10-20021217/">User
-Agent Accessibility Guidelines 1.0</titleref>, W3C Recommendation, 17
-December 2002. (See
-<xspecref href="http://www.w3.org/TR/2002/REC-UAAG10-20021217/">http://www.w3.org/TR/2002/REC-UAAG10-20021217/</xspecref>.)
-</bibl>
-<bibl id="utc" key="UTC">
-Recommendation TF.460,
-<titleref
-href="http://www.itu.int/">Standard-Frequency and Time-Signal
-Emissions</titleref>, International
-Telecommunciations Union, Radio Sector (ITU-R).
-</bibl>
-<bibl id="uax14" key="UAX14">Asmus Freytag, <titleref
-href="http://www.unicode.org/reports/tr14/tr14-17.html">Line Breaking
-Properties</titleref>, Unicode Consortium, 29 August 2005. (See
-<xspecref
-href="http://www.unicode.org/reports/tr14/tr14-17.html">http://www.unicode.org/reports/tr14/tr14-17.html</xspecref>.)
-</bibl>
-<bibl id="wcag" key="WCAG">Ben Caldwell, et al., Eds.,
-<titleref href="http://www.w3.org/TR/2008/REC-WCAG20-20081211/">Web
-Content Accessibility Guidelines (WCAG) 2.0</titleref>, W3C Recommendation, 11 December 2008. (See
-<xspecref href="http://www.w3.org/TR/2008/REC-WCAG20-20081211/">http://www.w3.org/TR/2008/REC-WCAG20-20081211/</xspecref>.)
-</bibl>
-<bibl id="xml10" key="XML 1.0">Tim Bray, et al.
-<titleref href="http://www.w3.org/TR/2008/REC-xml-20081126/">Extensible Markup Language (XML)
-1.0 (Fifth Edition)</titleref>, W3C Recommendation, 26 November 2008. (See
-<xspecref href="http://www.w3.org/TR/2008/REC-xml-20081126/">http://www.w3.org/TR/2008/REC-xml-20081126/</xspecref>.)
-</bibl>
-<bibl id="xml11" key="XML 1.1">Tim Bray, et al.
-<titleref href="http://www.w3.org/TR/2006/REC-xml11-20060816/">Extensible Markup Language (XML)
-1.1 (Second Edition)</titleref>, W3C Recommendation, 16 August 2006, edited in place 29 September 2006. (See
-<xspecref href="http://www.w3.org/TR/2006/REC-xml11-20060816/">http://www.w3.org/TR/2006/REC-xml11-20060816/</xspecref>.)
-</bibl>
-<bibl id="xmlbase" key="XML Base">Jonathan Marsh and Richard Tobin, Eds.,
-<titleref href="http://www.w3.org/TR/2009/REC-xmlbase-20090128/">XML Base (Second Edition)</titleref>,
-W3C Recommendation, 28 January 2009. (See
-<xspecref href="http://www.w3.org/TR/2009/REC-xmlbase-20090128/">http://www.w3.org/TR/2009/REC-xmlbase-20090128/</xspecref>.)
-</bibl>
-<bibl id="xmlid" key="XML ID">Jonathan Marsh, Daniel Veillard, Norman Walsh, Eds.,
-<titleref href="http://www.w3.org/TR/2005/REC-xml-id-20050909/">xml:id Version 1.0</titleref>,
-W3C Recommendation, 09 September 2005. (See
-<xspecref href="http://www.w3.org/TR/2005/REC-xml-id-20050909/">http://www.w3.org/TR/2005/REC-xml-id-20050909/</xspecref>.)
-</bibl>
-<bibl id="xml-media" key="XML Media">Makato Murata, Simon St. Laurent,
-Kan Khon, Eds., <titleref
-href="http://www.rfc-editor.org/rfc/rfc3023.txt">XML Media Types</titleref>,
-RFC 3023, January 2001, IETF.(See
-<xspecref
-href="http://www.rfc-editor.org/rfc/rfc3023.txt">http://www.rfc-editor.org/rfc/rfc3023.txt</xspecref>.)
-</bibl>
-<bibl id="infoset" key="XML InfoSet">John Cowan and Richard Tobin, Eds.,
-<titleref href="http://www.w3.org/TR/2004/REC-xml-infoset-20040204/">XML Information Set (Second Edition)</titleref>,
-W3C Recommendation, 04 February 2004. (See
-<xspecref href="http://www.w3.org/TR/2004/REC-xml-infoset-20040204/">http://www.w3.org/TR/2004/REC-xml-infoset-20040204/</xspecref>.)
-</bibl>
-<bibl id="rfc3023" key="XML Media Types">Makato Murata, et al.,
-<titleref
-href="http://www.rfc-editor.org/rfc/rfc3023.txt">XML Media Types</titleref>,
-RFC 3023, January 2001, IETF.(See
-<xspecref
-href="http://www.rfc-editor.org/rfc/rfc3023.txt">http://www.rfc-editor.org/rfc/rfc3023.txt</xspecref>.)
-</bibl>
-<bibl id="xmlns10" key="XML Namespaces 1.0">Tim Bray, et al.
-<titleref href="http://www.w3.org/TR/2009/REC-xml-names-20091208/">Namespaces
-in XML 1.0 (Third Edition)</titleref>, W3C Recommendation, 8 December 2009. (See
-<xspecref href="http://www.w3.org/TR/2009/REC-xml-names-20091208/">http://www.w3.org/TR/2009/REC-xml-names-20091208/</xspecref>.)
-</bibl>
-<bibl id="xsd-1" key="XML Schema Part 1">Henry S. Thompson, David Beech,
-Murray Maloney, Noah Mendelsohn, Eds.,
-<titleref href="http://www.w3.org/TR/xmlschema-1/">XML Schema Part 1: Structures</titleref>,
-W3C Recommendation, 28 October 2004. (See
-<xspecref href="http://www.w3.org/TR/xmlschema-1/">http://www.w3.org/TR/xmlschema-1/</xspecref>.)
-</bibl>
-<bibl id="xsd-2" key="XML Schema Part 2">Paul Biron and Ashok Malhotra,
-<titleref href="http://www.w3.org/TR/xmlschema-2/">XML Schema Part 2: Datatypes</titleref>,
-W3C Recommendation, 28 October 2004. (See
-<xspecref href="http://www.w3.org/TR/xmlschema-2/">http://www.w3.org/TR/xmlschema-2/</xspecref>.)
-</bibl>
-<bibl id="xsl11" key="XSL 1.1">Anders Berglund,
-<titleref href="http://www.w3.org/TR/2006/REC-xsl11-20061205/">Extensible Stylesheet Language (XSL) Version 1.1</titleref>,
-W3C Recommendation, 05 December 2006. (See
-<xspecref href="http://www.w3.org/TR/2006/REC-xsl11-20061205/">http://www.w3.org/TR/2006/REC-xsl11-20061205/</xspecref>.)
-</bibl>
-</blist>
-</div1>
-<inform-div1 id="other-references">
-<head>Other References</head>
-<blist>
-<bibl id="ccreq" key="CC-DECODER-REQ"><titleref
-href="http://edocket.access.gpo.gov/cfr_2005/octqtr/47cfr15.119.htm">Closed Caption Decoder
-Requirements for Analog Television</titleref>,
-United States Code of Federal Regulations, Title 47, Volume 1, Part 15, &sect; 15.119. (See
-<xspecref href="http://edocket.access.gpo.gov/cfr_2005/octqtr/47cfr15.119.htm">http://edocket.access.gpo.gov/cfr_2005/octqtr/47cfr15.119.htm</xspecref>.)
-</bibl>
-<bibl id="cea608c" key="CEA-608-C">
-EIA/CEA-608-C,
-<titleref href="http://www.ce.org/">Line 21 Data
-Services</titleref>, EIA/CEA Standard,
-Consumer Electronics Association (CEA).
-</bibl>
-<bibl id="css3-color" key="CSS3 Color">Tantek &Ccedil;elik and Chris Lilley,
-<titleref href="http://www.w3.org/TR/2003/CR-css3-color-20030514/">CSS3 Color
-Module</titleref>, W3C Candidate Recommendation, 14 May 2003. (See
-<xspecref href="http://www.w3.org/TR/2003/CR-css3-color-20030514/">http://www.w3.org/TR/2003/CR-css3-color-20030514/</xspecref>.)
-</bibl>
-<bibl id="dcmes" key="DCMES 1.1">Dublin Core Metadata Initiative,
-<titleref href="http://dublincore.org/documents/dces/">Dublin Core Metadata Element Set, Version 1.1: Reference Description</titleref>. (See
-<xspecref href="http://dublincore.org/documents/dces/">http://dublincore.org/documents/dces/</xspecref>.)
-</bibl>
-<bibl id="mpeg7-5" key="MPEG7-5">
-ISO/IEC 15938-5,
-<titleref
-href="http://www.iso.org/">Information technology &ndash; Multimedia content description
-interface &ndash; Part 5: Multimedia description schemes</titleref>,
-International Organization for Standardization (ISO).
-</bibl>
-<bibl id="nsstate" key="NSState">Norman Walsh, Ed.,
-<titleref
-href="http://www.w3.org/2001/tag/doc/namespaceState-2006-01-09.html">The Disposition
-of Names in an XML Namespace</titleref>, TAG Finding, 9 January 2006. (See
-<xspecref href="http://www.w3.org/2001/tag/doc/namespaceState-2006-01-09.html">http://www.w3.org/2001/tag/doc/namespaceState-2006-01-09</xspecref>.)
-</bibl>
-<bibl id="qaf-sg" key="QAF SG">Karl Dubost, et al.,
-<titleref
-href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/">QA
-Framework: Specifications Guidelines</titleref>, W3C Recommendation, 17
-August 2005. (See
-<xspecref href="http://www.w3.org/TR/qaframe-spec/">http://www.w3.org/TR/qaframe-spec/</xspecref>.)
-</bibl>
-<bibl id="smpte170m" key="SMPTE 170M">ANSI/SMPTE 170M, 
-<titleref
-href="http://www.smpte.org/">Television &ndash; Composite Analog Video
-Signal &ndash; NTSC for Studio Applications</titleref>, SMPTE Standard.
-</bibl>
-<bibl id="svg11" key="SVG 1.1">Jon Ferraiolo, Jun Fujisawa, Dean Jackson, Eds.,
-<titleref
-href="http://www.w3.org/TR/2003/REC-SVG11-20030114/">Scalable
-Vector Graphics (SVG) 1.1 Specification</titleref>, W3C Recommendation, 14
-January 2003. (See
-<xspecref href="http://www.w3.org/TR/2003/REC-SVG11-20030114/">http://www.w3.org/TR/2003/REC-SVG11-20030114/</xspecref>.)
-</bibl>
-<bibl id="ttaf1-req" key="TTAF1-REQ">Glenn Adams, Ed.,
-<titleref href="http://www.w3.org/TR/2006/NOTE-ttaf1-req-20060427/">Timed Text (TT) Authoring Format 1.0 Use
-Cases and Requirements</titleref>,
-W3C Working Group Note, 27 April 2006. (See
-<xspecref
-href="http://www.w3.org/TR/2006/NOTE-ttaf1-req-20060427/">http://www.w3.org/TR/2006/NOTE-ttaf1-req-20060427/</xspecref>.)
-</bibl>
-<bibl id="xhtml10" key="XHTML 1.0">Steven Pemberton, et al.,
-<titleref
-href="http://www.w3.org/TR/2002/REC-xhtml1-20020801/">XHTML&trade; 1.0,
-The Extensible Hypertext Markup Language (Second Edition)</titleref>,
-W3C Recommendation, 01
-August 2002. (See
-<xspecref href="http://www.w3.org/TR/2002/REC-xhtml1-20020801/">http://www.w3.org/TR/2002/REC-xhtml1-20020801/</xspecref>.)
-</bibl>
-</blist>
-</inform-div1>
-<inform-div1 id="requirements">
-<head>Requirements</head>
-<p>The Distribution Format Exchange Profile (DFXP) of the Timed Text Authoring
-Format (TTML) satisfies a subset of the requirements established by
-<bibref ref="ttaf1-req"/>. The following table enumerates these requirements and
-indicates the extent to which they are satisfied by this specification, where
-<emph>S</emph> denotes a requirement is satisfied, <emph>P</emph> denotes
-a requirement is partially satisfied, and <emph>N</emph> denotes a
-requirement is not satisfied.</p>
-<table id="requirements-table" role="common">
-<caption>Table J-1 &ndash; Requirement Satisfaction</caption>
-<col width="10%"/>
-<col width="40%"/>
-<col width="10%"/>
-<tbody>
-<tr>
-<th>ID</th>
-<th>Name</th>
-<th>Status</th>
-<th>Comments</th>
-</tr>
-<tr>
-<td>R100</td>
-<td>Specification Format</td>
-<td>S</td>
-<td/>
-</tr>
-<tr>
-<td>R101</td>
-<td>Specification Modularity</td>
-<td>S</td>
-<td/>
-</tr>
-<tr>
-<td>R102</td>
-<td>Specification Organization</td>
-<td>S</td>
-<td/>
-</tr>
-<tr>
-<td>R103</td>
-<td>Core and Periphery</td>
-<td>S</td>
-<td>TT extension namespaces</td>
-</tr>
-<tr>
-<td>R104</td>
-<td>Evolution of Core</td>
-<td>S</td>
-<td>TT extension namespaces</td>
-</tr>
-<tr>
-<td>R105</td>
-<td>Ownership of Core</td>
-<td>S</td>
-<td>TT namespaces</td>
-</tr>
-<tr>
-<td>R106</td>
-<td>Surjection of Core</td>
-<td>S</td>
-<td/>
-</tr>
-<tr>
-<td>R107</td>
-<td>Evolution of Periphery</td>
-<td>S</td>
-<td>TT extension namespaces</td>
-</tr>
-<tr>
-<td>R108</td>
-<td>Ownership of Periphery</td>
-<td>S</td>
-<td>Non-TT namespaces</td>
-</tr>
-<tr>
-<td>R109</td>
-<td>Transformation</td>
-<td>S</td>
-<td>Supports 3GPP, QText, RealText, SAMI</td>
-</tr>
-<tr>
-<td>R110</td>
-<td>Streamable Transformation</td>
-<td>S</td>
-<td>Progressive decoding</td>
-</tr>
-<tr>
-<td>R111</td>
-<td>Accessibility &ndash; Content</td>
-<td>S</td>
-<td>Alternative document instances</td>
-</tr>
-<tr>
-<td>R112</td>
-<td>Accessibility &ndash; Authoring System</td>
-<td>S</td>
-<td/>
-</tr>
-<tr>
-<td>R200</td>
-<td>Authorability</td>
-<td>S</td>
-<td/>
-</tr>
-<tr>
-<td>R201</td>
-<td>Multiple Natural Languages</td>
-<td>S</td>
-<td>Alternative document instances</td>
-</tr>
-<tr>
-<td>R202</td>
-<td>Natural Language Coverage</td>
-<td>S</td>
-<td>Unicode 4.0</td>
-</tr>
-<tr>
-<td>R203</td>
-<td>Natural Language Association Granularity</td>
-<td>S</td>
-<td>See <code>xml:lang</code></td>
-</tr>
-<tr>
-<td>R204</td>
-<td>Minimum Character Representability</td>
-<td>S</td>
-<td>Unicode 4.0</td>
-</tr>
-<tr>
-<td>R205</td>
-<td>Intrinsic and Extrinsic Text Content</td>
-<td>P</td>
-<td>Intrinsic only</td>
-</tr>
-<tr>
-<td>R206</td>
-<td>Markup Association</td>
-<td>P</td>
-<td>Intrinsic only</td>
-</tr>
-<tr>
-<td>R207</td>
-<td>Conditional Content</td>
-<td>N</td>
-<td/>
-</tr>
-<tr>
-<td>R208</td>
-<td>Flowed Text</td>
-<td>S</td>
-<td/>
-</tr>
-<tr>
-<td>R209</td>
-<td>Logical Flowed Text Vocabulary</td>
-<td>S</td>
-<td/>
-</tr>
-<tr>
-<td>R210</td>
-<td>Presentational Flowed Text Vocabulary</td>
-<td>S</td>
-<td>Implied mapping from logical flowed text.</td>
-</tr>
-<tr>
-<td>R211</td>
-<td>Flowed Text Vocabulary Relationship</td>
-<td>S</td>
-<td/>
-</tr>
-<tr>
-<td>R212</td>
-<td>Flowed Text Vocabulary Separation</td>
-<td>N</td>
-<td/>
-</tr>
-<tr>
-<td>R213</td>
-<td>Non-Flowed Text</td>
-<td>N</td>
-<td/>
-</tr>
-<tr>
-<td>R214</td>
-<td>Non-Flowed Text Vocabulary</td>
-<td>N</td>
-<td/>
-</tr>
-<tr>
-<td>R215</td>
-<td>Hybrid Flowed and Non-Flowed Text</td>
-<td>N</td>
-<td/>
-</tr>
-<tr>
-<td>R216</td>
-<td>Hyperlinking</td>
-<td>N</td>
-<td>Can support via XLink</td>
-</tr>
-<tr>
-<td>R217</td>
-<td>Embedded Graphics</td>
-<td>N</td>
-<td/>
-</tr>
-<tr>
-<td>R218</td>
-<td>Non-Embedded Graphics</td>
-<td>N</td>
-<td/>
-</tr>
-<tr>
-<td>R219</td>
-<td>Embedded Fonts</td>
-<td>N</td>
-<td/>
-</tr>
-<tr>
-<td>R220</td>
-<td>Non-Embedded Fonts</td>
-<td>N</td>
-<td/>
-</tr>
-<tr>
-<td>R221</td>
-<td>Descriptive Vocabulary</td>
-<td>S</td>
-<td>See <code>ttm:agent</code>, <code>ttm:role</code></td>
-</tr>
-<tr>
-<td>R222</td>
-<td>Embedded Audio</td>
-<td>N</td>
-<td/>
-</tr>
-<tr>
-<td>R223</td>
-<td>Non-Embedded Audio</td>
-<td>N</td>
-<td/>
-</tr>
-<tr>
-<td>R290</td>
-<td>Markup Format</td>
-<td>S</td>
-<td/>
-</tr>
-<tr>
-<td>R291</td>
-<td>Markup Format and Unicode Interaction</td>
-<td>S</td>
-<td/>
-</tr>
-<tr>
-<td>R292</td>
-<td>Extrinsic Resource References</td>
-<td>N</td>
-<td>No extrinsic references</td>
-</tr>
-<tr>
-<td>R293</td>
-<td>Schema Validity Specification</td>
-<td>S</td>
-<td/>
-</tr>
-<tr>
-<td>R300</td>
-<td>Inline Styling</td>
-<td>S</td>
-<td/>
-</tr>
-<tr>
-<td>R301</td>
-<td>Inline Styling Form</td>
-<td>P</td>
-<td>Inline and referential styling</td>
-</tr>
-<tr>
-<td>R301</td>
-<td>Out-of-Line Styling</td>
-<td>N</td>
-<td/>
-</tr>
-<tr>
-<td>R301</td>
-<td>Out-of-Line Styling Form</td>
-<td>N</td>
-<td/>
-</tr>
-<tr>
-<td>R304</td>
-<td>Styling Prioritization</td>
-<td>S</td>
-<td/>
-</tr>
-<tr>
-<td>R305</td>
-<td>Style Parameters &ndash; Aural</td>
-<td>N</td>
-<td/>
-</tr>
-<tr>
-<td>R306</td>
-<td>Style Parameters &ndash; Visual</td>
-<td>P</td>
-<td>Supports absolute position, background color, color, display none, display alignment,
-font family, font size, font style, font weight, height, line height, origin,
-opacity, overflow, padding (before, after, start, end), text alignment,
-text shadow (as outline), visibility, width, writing mode, z-index</td>
-</tr>
-<tr>
-<td>R390</td>
-<td>Style Parameter Symmetry</td>
-<td>S</td>
-<td/>
-</tr>
-<tr>
-<td>R391</td>
-<td>Style Parameter Definitions</td>
-<td>S</td>
-<td/>
-</tr>
-<tr>
-<td>R392</td>
-<td>Style Parameter Shorthands</td>
-<td>S</td>
-<td/>
-</tr>
-<tr>
-<td>R401</td>
-<td>Inline Timing</td>
-<td>S</td>
-<td/>
-</tr>
-<tr>
-<td>R402</td>
-<td>Out-of-Line Timing</td>
-<td>N</td>
-<td/>
-</tr>
-<tr>
-<td>R403</td>
-<td>Synchronization Parameters</td>
-<td>P</td>
-<td>Supports begin, end, dur</td>
-</tr>
-<tr>
-<td>R404</td>
-<td>Synchronization Parameter Value Spaces</td>
-<td>P</td>
-<td>Supports offset values, media marker values (SMPTE 12M), wallclock values</td>
-</tr>
-<tr>
-<td>R405</td>
-<td>Time Containment Semantics</td>
-<td>P</td>
-<td>Supports sequential, parallel</td>
-</tr>
-<tr>
-<td>R500</td>
-<td>Animation Modes</td>
-<td>P</td>
-<td>Supports discrete</td>
-</tr>
-<tr>
-<td>R502</td>
-<td>Highlight Animation</td>
-<td>S</td>
-<td><code>&lt;set tts:backgroundColor="..."/&gt;</code></td>
-</tr>
-<tr>
-<td>R503</td>
-<td>Fade Transition Animation</td>
-<td>S</td>
-<td><code>&lt;set tts:opacity="..."/&gt;</code></td>
-</tr>
-<tr>
-<td>R504</td>
-<td>Animated Style Parameters &ndash; Aural</td>
-<td>N</td>
-<td/>
-</tr>
-<tr>
- <td>R505</td>
-<td>Animated Style Parameters &ndash; Visual</td>
-<td>P</td>
-<td>Supports animating background color, color, display, opacity, origin, visibility</td>
-</tr>
-<tr>
-<td>N506</td>
-<td>Animated Content</td>
-<td>S</td>
-<td/>
-</tr>
-<tr>
-<td>R600</td>
-<td>Metadata Item Association</td>
-<td>S</td>
-<td>See <code>metadata</code>, <code>Metadata.class</code></td>
-</tr>
-<tr>
-<td>R601</td>
-<td>Metadata Item Constituents</td>
-<td>P</td>
-<td>Supports name, value</td>
-</tr>
-<tr>
-<td>R602</td>
-<td>Metadata Item Value Representation</td>
-<td>P</td>
-<td>See <code>metadata</code></td>
-</tr>
-<tr>
-<td>R603</td>
-<td>Metadata Item Extensibility</td>
-<td>S</td>
-<td>See <code>metadata</code></td>
-</tr>
-<tr>
-<td>R604</td>
-<td>Metadata Item Validation</td>
-<td>S</td>
-<td>See <code>metadata</code></td>
-</tr>
-<tr>
-<td>R690</td>
-<td>Dublin Core Preference</td>
-<td>N</td>
-<td>Uses <code>ttm:copyright</code>, <code>ttm:desc</code>, <code>ttm:title</code></td>
-</tr>
-</tbody>
-</table>
-</inform-div1>
-<inform-div1 id="derivation">
-<head>Vocabulary Derivation</head>
-<p>This appendix provides information about the derivation of TTML
-vocabulary, separately describing derivation of elements and
-attributes.</p>
-<div2>
-<head>Element Derivation</head>
-<p>The first column of <specref ref="element-vocab-derivation-table"/>
-specifies a TTML element vocabulary item; the second column specifies the
-syntactic and/or semantic model on which the vocabulary item is based;
-the third column specifies the reference that defines
-the model (if a model is indicated);
-the fourth column specifies details about the derivation; the last
-column refers to additional notes describing the nature of the
-derivation.</p>
-<p>In the fourth column, which describes details of derivation, a
-notation is use to indicate the addition or removal of an attribute.
-For example, in the derivation of the <el>tt:div</el> element, the
-details column includes "-@class", which denotes that the
-<att>class</att> attribute that is specified for use with the
-<el>xhtml:div</el> model element is not specified for use with the
-corresponding TTML element; in contrast, the details column includes
-"+@begin", which denotes that a <att>begin</att> attribute is added
-that is not specified for use with the <el>xhtml:div</el> model
-element.</p>
-<table id="element-vocab-derivation-table" role="common">
-<caption>Table K-1 &ndash; Elements</caption>
-<col width="20%"/>
-<col width="17%"/>
-<col width="13%" align="center"/>
-<col width="40%"/>
-<col width="10%" align="center"/>
-<tbody>
-<tr>
-<td><phrase role="strong">Element</phrase></td>
-<td><phrase role="strong">Model</phrase></td>
-<td><phrase role="strong">Reference</phrase></td>
-<td><phrase role="strong">Details</phrase></td>
-<td><phrase role="strong">Notes</phrase></td>
-</tr>
-<tr>
-<td><loc href="#document-structure-vocabulary-body"><code>tt:body</code></loc></td>
-<td><code>xhtml:body</code></td>
-<td><bibref ref="xhtml10"/></td>
-<td>-@class, -@dir, -@lang, -@on*, -@title; +@begin, +@dur, +@end, +@region,
-+@timeContainer, +@ttm:*, +@tts:*; content model
-subsetted to zero or more division (div) children, and supersetted by
-optional metadata and animation children</td>
-<td>1,2</td>
-</tr>
-<tr>
-<td><loc href="#content-vocabulary-br"><code>tt:br</code></loc></td>
-<td><code>xhtml:br</code></td>
-<td><bibref ref="xhtml10"/></td>
-<td>-@class, -@title; +@ttm:*, +@tts:*, +@xml:lang, +@xml:space;
-content model supersetted by
-optional metadata and animation children for congruity with other
-content vocabulary</td>
-<td>1,2</td>
-</tr>
-<tr>
-<td><loc href="#content-vocabulary-div"><code>tt:div</code></loc></td>
-<td><code>xhtml:div</code></td>
-<td><bibref ref="xhtml10"/></td>
-<td>-@class, -@dir, -@lang, -@on*, -@title; +@begin, +@dur, +@end, +@region,
-+@timeContainer, +@ttm:*, +@tts:*, +@xml:space; content model
-subsetted to zero or more paragraph (p) children, and supersetted by
-optional metadata and animation children</td>
-<td>1,2,3</td>
-</tr>
-<tr>
-<td><loc href="#document-structure-vocabulary-head"><code>tt:head</code></loc></td>
-<td><code>xhtml:head</code></td>
-<td><bibref ref="xhtml10"/></td>
-<td>-@dir, -@lang, -@profile; +@id, +@xml:space; content model changed to
-optional metadata children, followed by optional styling child,
-followed by optional layout child</td>
-<td>1,3</td>
-</tr>
-<tr>
-<td><loc href="#layout-vocabulary-layout"><code>tt:layout</code></loc></td>
-<td><code>fo:simple-page-master</code></td>
-<td><bibref ref="xsl11"/></td>
-<td>conceptual derivation</td>
-<td>4</td>
-</tr>
-<tr>
-<td><loc href="#metadata-vocabulary-metadata"><code>tt:metadata</code></loc></td>
-<td><code>svg:metadata</code></td>
-<td><bibref ref="svg11"/></td>
-<td>-@xml:base; +@ttm:*, +@xml:lang, +@xml:space; content model
-subsetted to foreign namespace element content only (no #PCDATA)</td>
-<td>3,5</td>
-</tr>
-<tr>
-<td><loc href="#content-vocabulary-p"><code>tt:p</code></loc></td>
-<td><code>xhtml:p</code></td>
-<td><bibref ref="xhtml10"/></td>
-<td>-@class, -@dir, -@lang, -@on*, -@title; +@begin, +@dur, +@end, +@region,
-+@timeContainer, +@ttm:*, +@tts:*, +@xml:space; content model
-subsetted to zero or more span children, and supersetted by optional
-metadata and animation children</td>
-<td>1,2,3</td>
-</tr>
-<tr>
-<td><loc href="#layout-vocabulary-region"><code>tt:region</code></loc></td>
-<td><code>fo:region-*</code></td>
-<td><bibref ref="xsl11"/></td>
-<td>conceptual derivation</td>
-<td>4</td>
-</tr>
-<tr>
-<td><loc href="#animation-vocabulary-set"><code>tt:set</code></loc></td>
-<td><code>svg:set</code></td>
-<td><bibref ref="svg11"/></td>
-<td>-@* except begin, dur, end; +@tts:*, +@xml:lang, +@xml:space</td>
-<td>3,6</td>
-</tr>
-<tr>
-<td><loc href="#content-vocabulary-span"><code>tt:span</code></loc></td>
-<td><code>xhtml:span</code></td>
-<td><bibref ref="xhtml10"/></td>
-<td>-@class, -@dir, -@lang, -@on*, -@title; +@begin, +@dur, +@end, +@region,
-+@timeContainer, +@ttm:*, +@tts:*, +@xml:space; content model
-subsetted to zero or more #PCDATA or break (br) children, and
-supersetted by optional metadata and animation children</td>
-<td>1,2,3</td>
-</tr>
-<tr>
-<td><loc href="#styling-vocabulary-style"><code>tt:style</code></loc></td>
-<td><emph>style specification</emph></td>
-<td><bibref ref="css2"/></td>
-<td>XML representation of identified set of pairs of style property
-name and value, with optional inclusion of other styles by reference
-to other style elements</td>
-<td>7</td>
-</tr>
-<tr>
-<td><loc href="#styling-vocabulary-styling"><code>tt:styling</code></loc></td>
-<td><code>xhtml:style</code></td>
-<td><bibref ref="xhtml10"/></td>
-<td>XML representation of a set of style specifications sets, each
-represented by a style child element</td>
-<td>1,7</td>
-</tr>
-<tr>
-<td><loc href="#document-structure-vocabulary-tt"><code>tt:tt</code></loc></td>
-<td><code>xhtml:html</code></td>
-<td><bibref ref="xhtml10"/></td>
-<td>-@dir, -@lang; +@id, +@ttp:*, +@xml:space; content model subsetted by
-permitting body and/or head to be optional</td>
-<td>1,8</td>
-</tr>
-<tr>
-<td><loc href="#metadata-vocabulary-actor"><code>ttm:actor</code></loc></td>
-<td><code>mpeg7:Creator</code></td>
-<td><bibref ref="mpeg7-5"/></td>
-<td>conceptual derivation</td>
-<td>4</td>
-</tr>
-<tr>
-<td><loc href="#metadata-vocabulary-agent"><code>ttm:agent</code></loc></td>
-<td><code>mpeg7:Agent</code></td>
-<td><bibref ref="mpeg7-5"/></td>
-<td>conceptual derivation</td>
-<td>4</td>
-</tr>
-<tr>
-<td><loc href="#metadata-vocabulary-copyright"><code>ttm:copyright</code></loc></td>
-<td><code>mpeg7:CopyrightString</code></td>
-<td><bibref ref="mpeg7-5"/></td>
-<td>conceptual derivation</td>
-<td>4</td>
-</tr>
-<tr>
-<td><loc href="#metadata-vocabulary-desc"><code>ttm:desc</code></loc></td>
-<td><code>svg:desc</code></td>
-<td><bibref ref="svg11"/></td>
-<td>-@class, -@style, -@xml:base</td>
-<td>2,5,9</td>
-</tr>
-<tr>
-<td><loc href="#metadata-vocabulary-name"><code>ttm:name</code></loc></td>
-<td><code>mpeg7:Name</code></td>
-<td><bibref ref="mpeg7-5"/></td>
-<td>conceptual derivation</td>
-<td>4</td>
-</tr>
-<tr>
-<td><loc href="#metadata-vocabulary-title"><code>ttm:title</code></loc></td>
-<td><code>svg:title</code></td>
-<td><bibref ref="svg11"/></td>
-<td>-@class, -@style, -@xml:base</td>
-<td>2,5,9</td>
-</tr>
-
-<tr>
-<td><loc href="#parameter-vocabulary-extension"><code>ttp:extension</code></loc></td>
-<td><code>@requiredExtensions</code></td>
-<td><bibref ref="svg11"/></td>
-<td>conceptual derivation</td>
-<td>10</td>
-</tr>
-<tr>
-<td><loc href="#parameter-vocabulary-extensions"><code>ttp:extensions</code></loc></td>
-<td><code>@requiredExtensions</code></td>
-<td><bibref ref="svg11"/></td>
-<td>conceptual derivation</td>
-<td>10</td>
-</tr>
-<tr>
-<td><loc href="#parameter-vocabulary-feature"><code>ttp:feature</code></loc></td>
-<td><code>@requiredFeatures</code></td>
-<td><bibref ref="svg11"/></td>
-<td>conceptual derivation</td>
-<td>10</td>
-</tr>
-<tr>
-<td><loc href="#parameter-vocabulary-features"><code>ttp:features</code></loc></td>
-<td><code>@requiredFeatures</code></td>
-<td><bibref ref="svg11"/></td>
-<td>conceptual derivation</td>
-<td>10</td>
-</tr>
-<tr>
-<td><loc href="#parameter-vocabulary-profile"><code>ttp:profile</code></loc></td>
-<td><code>@baseProfile</code></td>
-<td><bibref ref="svg11"/></td>
-<td>conceptual derivation</td>
-<td>11</td>
-</tr>
-</tbody>
-</table>
-<note>
-<olist>
-<item>
-<p>Derivation is indicated with respect to the strict DTD defined
-by <bibref ref="xhtml10"/>, &sect;A.1.</p>
-</item>
-<item>
-<p>The <att>class</att> attribute is effectively replaced by the
-<att>style</att>
-attribute, which, instead of specifying an inline style,
-refers indirectly to one or more <loc
-href="#styling-vocabulary-style"><el>style</el></loc>
-elements that define a set of style specification sets.</p>
-</item>
-<item>
-<p>The <att>xml:lang</att> and <att>xml:space</att> attributes are defined for all element
-types in order to support their inheritance semantics to operate in
-the context of foreign namespace elements.</p>
-</item>
-<item>
-<p>Derivation is conceptual (notional) only.</p>
-</item>
-<item>
-<p>The <att>xml:base</att> attribute is not used since there are no external
-references from core vocabulary.</p>
-</item>
-<item>
-<p>The <att>attributeName</att> and <att>to</att> attributes of
-<el>svg:set</el> are replaced by the
-direct expression of the target attribute name and value by use of a
-<att>tts:*</att> attribute.</p>
-</item>
-<item>
-<p>CSS style specification syntax is mapped to XML by use of
-attributes defined in the TT Style Namespace.</p>
-</item>
-<item>
-<p>The <att>xml:id</att> attribute is defined for use on all element types.</p>
-</item>
-<item>
-<p>The <att>style</att> attribute is supported only on content
-elements.</p>
-</item>
-<item>
-<p>Derived from the use of <code>@requiredExtensions</code>
-and <code>@requiredFeatures</code> on the <code>svg:svg</code> element,
-but extended to support distinct specification of optionality.</p>
-</item>
-<item>
-<p>Derived from the use of <code>@baseProfile</code>
-and <code>@version</code> on the <code>svg:svg</code> element.</p>
-</item>
-</olist>
-</note>
-</div2>
-<div2>
-<head>Attribute Derivation</head>
-<p>The first column of <specref ref="attribute-vocab-derivation-table"/>
-specifies a TTML attribute vocabulary item; the second column specifies the
-syntactic and/or semantic model on which the vocabulary item is based;
-the third column specifies the reference that defines
-the model (if a model is indicated);
-the fourth column specifies details about the derivation; the last
-column refers to additional notes describing the nature of the
-derivation.</p>
-<p>In the fourth column, which describes details of derivation, a
-notation is use to indicate the addition or removal of an attribute
-value.  For example, in the derivation of the <att>timeContainer</att>
-attribute,
-the details column includes "-excl", which denotes that the
-<code>excl</code> value that is specified for use with the
-<att>timeContainer</att> model attribute is not specified for use with the
-corresponding TTML attribute; similarly, an "+<emph>value</emph>"
-in the details column indicates that the attribute's values have been
-extended to include <emph>value</emph>.</p>
-<p>Only those attributes that are specified for use on more than one TTML
-element type are listed below. Those per-element namespace attributes
-that are uniquely defined for a specific TTML element type are not
-listed below, but are considered to be part of the specific element
-type's derivation described in <specref
-ref="element-vocab-derivation-table"/>
-above.</p>
-<table id="attribute-vocab-derivation-table" role="common">
-<caption>Table K-2 &ndash; Attributes</caption>
-<col width="20%"/>
-<col width="17%"/>
-<col width="13%" align="center"/>
-<col width="40%"/>
-<col width="10%" align="center"/>
-<tbody>
-<tr>
-<td><phrase role="strong">Attribute</phrase></td>
-<td><phrase role="strong">Model</phrase></td>
-<td><phrase role="strong">Reference</phrase></td>
-<td><phrase role="strong">Details</phrase></td>
-<td><phrase role="strong">Notes</phrase></td>
-</tr>
-<tr>
-<td><loc href="#timing-attribute-begin"><code>begin</code></loc></td>
-<td><code>begin</code></td>
-<td><bibref ref="smil21"/></td>
-<td>see notes</td>
-<td>2,3,4</td>
-</tr>
-<tr>
-<td><loc href="#timing-attribute-dur"><code>dur</code></loc></td>
-<td><code>dur</code></td>
-<td><bibref ref="smil21"/></td>
-<td>see notes</td>
-<td>2,3,4</td>
-</tr>
-<tr>
-<td><loc href="#timing-attribute-end"><code>end</code></loc></td>
-<td><code>end</code></td>
-<td><bibref ref="smil21"/></td>
-<td>see notes</td>
-<td>2,3,4</td>
-</tr>
-<tr>
-<td><loc href="#layout-attribute-region"><code>region</code></loc></td>
-<td><code>master-reference</code></td>
-<td><bibref ref="xsl11"/></td>
-<td>conceptual derivation</td>
-<td></td>
-</tr>
-<tr>
-<td><loc href="#style-attribute-style"><code>style</code></loc></td>
-<td><code>class</code></td>
-<td><bibref ref="css2"/></td>
-<td>dereferences style specification(s) directly</td>
-<td></td>
-</tr>
-<tr>
-<td><loc href="#timing-attribute-timeContainer"><code>timeContainer</code></loc></td>
-<td><code>timeContainer</code></td>
-<td><bibref ref="smil21"/></td>
-<td>-excl, -none; no default attribute value</td>
-<td>5</td>
-</tr>
-<tr>
-<td><loc href="#metadata-attribute-agent"><code>ttm:agent</code></loc></td>
-<td><emph>none</emph></td>
-<td></td>
-<td>used to attribute agent of content</td>
-<td></td>
-</tr>
-<tr>
-<td><loc href="#metadata-attribute-role"><code>ttm:role</code></loc></td>
-<td><emph>none</emph></td>
-<td></td>
-<td>used to attribute role of content</td>
-<td></td>
-</tr>
-<tr>
-<td><loc href="#parameter-attribute-cellResolution"><code>ttp:cellResolution</code></loc></td>
-<td><emph>none</emph></td>
-<td></td>
-<td>expresses uniform grid resolution for cell based coordinates</td>
-<td></td>
-</tr>
-<tr>
-<td><loc href="#parameter-attribute-clockMode"><code>ttp:clockMode</code></loc></td>
-<td><emph>none</emph></td>
-<td></td>
-<td>determines how to interpret time expressions</td>
-<td></td>
-</tr>
-<tr>
-<td><loc href="#parameter-attribute-frameRate"><code>ttp:frameRate</code></loc></td>
-<td><emph>none</emph></td>
-<td></td>
-<td>expresses integral frame rate</td>
-<td></td>
-</tr>
-<tr>
-<td><loc href="#parameter-attribute-frameRateMultiplier"><code>ttp:frameRateMultiplier</code></loc></td>
-<td><emph>none</emph></td>
-<td></td>
-<td>used to express non-integral, rational frame rates</td>
-<td></td>
-</tr>
-<tr>
-<td><loc href="#parameter-attribute-markerMode"><code>ttp:markerMode</code></loc></td>
-<td><emph>none</emph></td>
-<td></td>
-<td>expresses marker continuity semantics</td>
-<td></td>
-</tr>
-<tr>
-<td><loc href="#parameter-attribute-pixelAspectRatio"><code>ttp:pixelAspectRatio</code></loc></td>
-<td><emph>none</emph></td>
-<td></td>
-<td>expresses pixel aspect ratio of related media</td>
-<td></td>
-</tr>
-<tr>
-<td><loc href="#parameter-attribute-profile"><code>ttp:profile</code></loc></td>
-<td><emph>none</emph></td>
-<td></td>
-<td>expresses profile of TTML used by document instance</td>
-<td></td>
-</tr>
-<tr>
-<td><loc href="#parameter-attribute-dropMode"><code>ttp:dropMode</code></loc></td>
-<td><emph>none</emph></td>
-<td></td>
-<td>expresses frame counting (drop) modes</td>
-<td></td>
-</tr>
-<tr>
-<td><loc href="#parameter-attribute-subFrameRate"><code>ttp:subFrameRate</code></loc></td>
-<td><emph>none</emph></td>
-<td></td>
-<td>expresses sub-frame rate</td>
-<td></td>
-</tr>
-<tr>
-<td><loc href="#parameter-attribute-tickRate"><code>ttp:tickRate</code></loc></td>
-<td><emph>none</emph></td>
-<td></td>
-<td>used to interpret tick based time expressions</td>
-<td></td>
-</tr>
-<tr>
-<td><loc href="#parameter-attribute-timeBase"><code>ttp:timeBase</code></loc></td>
-<td><emph>none</emph></td>
-<td></td>
-<td>used to interpret semantics of time expressions</td>
-<td></td>
-</tr>
-<tr>
-<td><loc href="#style-attribute-backgroundColor"><code>tts:backgroundColor</code></loc></td>
-<td><code>background-color</code></td>
-<td><bibref ref="xsl11"/></td>
-<td><code>-inherit</code></td>
-<td>1,6</td>
-</tr>
-<tr>
-<td><loc href="#style-attribute-color"><code>tts:color</code></loc></td>
-<td><code>color</code></td>
-<td><bibref ref="xsl11"/></td>
-<td><code>-inherit</code></td>
-<td>6</td>
-</tr>
-<tr>
-<td><loc href="#style-attribute-direction"><code>tts:direction</code></loc></td>
-<td><code>direction</code></td>
-<td><bibref ref="xsl11"/></td>
-<td><code>-inherit</code></td>
-<td></td>
-</tr>
-<tr>
-<td><loc href="#style-attribute-display"><code>tts:display</code></loc></td>
-<td><code>display</code></td>
-<td><bibref ref="css2"/></td>
-<td>only <code>auto</code>, <code>none</code></td>
-<td></td>
-</tr>
-<tr>
-<td><loc href="#style-attribute-displayAlign"><code>tts:displayAlign</code></loc></td>
-<td><code>display-align</code></td>
-<td><bibref ref="xsl11"/></td>
-<td><code>-inherit</code></td>
-<td>1</td>
-</tr>
-<tr>
-<td><loc href="#style-attribute-extent"><code>tts:extent</code></loc></td>
-<td><code>width</code>, <code>height</code></td>
-<td><bibref ref="xsl11"/></td>
-<td>shorthand property</td>
-<td></td>
-</tr>
-<tr>
-<td><loc href="#style-attribute-fontFamily"><code>tts:fontFamily</code></loc></td>
-<td><code>font-family</code></td>
-<td><bibref ref="xsl11"/></td>
-<td><code>-inherit</code>, extends generic family names</td>
-<td>1</td>
-</tr>
-<tr>
-<td><loc href="#style-attribute-fontSize"><code>tts:fontSize</code></loc></td>
-<td><code>font-size</code></td>
-<td><bibref ref="xsl11"/></td>
-<td><code>-inherit</code></td>
-<td>1,7</td>
-</tr>
-<!--
-<tr>
-<td><loc href="#style-attribute-fontStyle"><code>tts:fontStyle</code></loc></td>
-<td><code>font-style</code></td>
-<td><bibref ref="xsl11"/></td>
-<td><code>-inherit</code>, uses alias <code>reverseOblique</code> for <code>backslant</code></td>
-<td>1</td>
-</tr>
--->
-<tr>
-<td><loc href="#style-attribute-fontWeight"><code>tts:fontWeight</code></loc></td>
-<td><code>font-weight</code></td>
-<td><bibref ref="xsl11"/></td>
-<td><code>-inherit</code>, <code>-bolder</code>, <code>-lighter</code>, <code>-&lt;number&gt;</code></td>
-<td>1</td>
-</tr>
-<tr>
-<td><loc href="#style-attribute-lineHeight"><code>tts:lineHeight</code></loc></td>
-<td><code>line-height</code></td>
-<td><bibref ref="xsl11"/></td>
-<td><code>-inherit</code>, <code>-&lt;number&gt;</code>, <code>-&lt;space&gt;</code></td>
-<td>1</td>
-</tr>
-<tr>
-<td><loc href="#style-attribute-opacity"><code>tts:opacity</code></loc></td>
-<td><code>opacity</code></td>
-<td><bibref ref="css3-color"/></td>
-<td><code>-inherit</code></td>
-<td></td>
-</tr>
-<tr>
-<td><loc href="#style-attribute-origin"><code>tts:origin</code></loc></td>
-<td><code>top</code>, <code>left</code></td>
-<td><bibref ref="xsl11"/></td>
-<td>shorthand property</td>
-<td></td>
-</tr>
-<tr>
-<td><loc href="#style-attribute-overflow"><code>tts:overflow</code></loc></td>
-<td><code>overflow</code></td>
-<td><bibref ref="xsl11"/></td>
-<td><code>-inherit</code>, <code>-auto</code>, <code>-error-if-overflow</code>;</td>
-<td>8</td>
-</tr>
-<tr>
-<td><loc href="#style-attribute-padding"><code>tts:padding</code></loc></td>
-<td><code>padding</code></td>
-<td><bibref ref="xsl11"/></td>
-<td><code>-inherit</code></td>
-<td>9</td>
-</tr>
-<tr>
-<td><loc href="#style-attribute-showBackground"><code>tts:showBackground</code></loc></td>
-<td><code>showBackground</code></td>
-<td><bibref ref="smil21"/></td>
-<td><code>-inherit</code></td>
-<td></td>
-</tr>
-<tr>
-<td><loc href="#style-attribute-textAlign"><code>tts:textAlign</code></loc></td>
-<td><code>text-align</code></td>
-<td><bibref ref="xsl11"/></td>
-<td><code>-inherit</code></td>
-<td>1</td>
-</tr>
-<tr>
-<td><loc href="#style-attribute-textDecoration"><code>tts:textDecoration</code></loc></td>
-<td><code>text-decoration</code></td>
-<td><bibref ref="xsl11"/></td>
-<td><code>-inherit</code></td>
-<td>1,10,13</td>
-</tr>
-<tr>
-<td><loc href="#style-attribute-textOutline"><code>tts:textOutline</code></loc></td>
-<td><code>text-shadow</code></td>
-<td><bibref ref="xsl11"/></td>
-<td><code>-inherit</code></td>
-<td>11,13</td>
-</tr>
-<tr>
-<td><loc href="#style-attribute-unicodeBidi"><code>tts:unicodeBidi</code></loc></td>
-<td><code>unicode-bidi</code></td>
-<td><bibref ref="xsl11"/></td>
-<td><code>-inherit</code></td>
-<td>1</td>
-</tr>
-<tr>
-<td><loc href="#style-attribute-visibility"><code>tts:visibility</code></loc></td>
-<td><code>visibility</code></td>
-<td><bibref ref="xsl11"/></td>
-<td><code>-inherit</code>, <code>-collapse</code></td>
-<td></td>
-</tr>
-<tr>
-<td><loc href="#style-attribute-wrapOption"><code>tts:wrapOption</code></loc></td>
-<td><code>wrap-option</code></td>
-<td><bibref ref="xsl11"/></td>
-<td><code>-inherit</code></td>
-<td>1</td>
-</tr>
-<tr>
-<td><loc href="#style-attribute-writingMode"><code>tts:writingMode</code></loc></td>
-<td><code>writing-mode</code></td>
-<td><bibref ref="xsl11"/></td>
-<td><code>-inherit</code>, <code>+tblr</code></td>
-<td>1</td>
-</tr>
-<tr>
-<td><loc href="#style-attribute-zIndex"><code>tts:zIndex</code></loc></td>
-<td><code>z-index</code></td>
-<td><bibref ref="xsl11"/></td>
-<td><code>-inherit</code></td>
-<td>1</td>
-</tr>
-<tr>
-<td><loc href="#content-attribute-id"><code>xml:id</code></loc></td>
-<td><code>xml:id</code></td>
-<td><bibref ref="xmlid"/></td>
-<td>complies with model</td>
-<td></td>
-</tr>
-<tr>
-<td><loc href="#content-attribute-lang"><code>xml:lang</code></loc></td>
-<td><code>xml:lang</code></td>
-<td><bibref ref="xml10"/></td>
-<td>complies with model</td>
-<td></td>
-</tr>
-<tr>
-<td><loc href="#content-attribute-space"><code>xml:space</code></loc></td>
-<td><code>xml:space</code></td>
-<td><bibref ref="xml10"/></td>
-<td>see notes</td>
-<td>12</td>
-</tr>
-</tbody>
-</table>
-<note>
-<olist>
-<item>
-<p>Attribute name and/or value(s) are normalized to use
-<emph>lowerCamelCase</emph> naming convention.</p>
-</item>
-<item>
-<p>Restricted to expressing a clock value that denotes one of the
-following in accordance to whether the parameter expressed by the
-<att>ttp:timeBase</att> attribute is <code>media</code>, <code>smpte</code>,
-or <code>clock</code>, respectively:
-(1) an offset from an implicit syncbase that is linked to a media time
-line, (2) an event time
-that represents the occurrence of an implicit media marker, or (3) a wallclock
-time.</p>
-</item>
-<item>
-<p>Syntactically subsets and supersets the <bibref
-ref="smil21"/>&nbsp;<code>Clock-value</code> syntax as follows:
-(1) requires non-negative <code>Full-clock-value</code> or
-<code>Timecount-value</code>;
-(2) if <code>Full-clock-value</code>
-then <emph>hours</emph> must be two or more digits;
-(3) if <code>Timecount-value</code>, then <emph>metric</emph> must be
-specified;
-(4) uses <code>m</code> as alias for <code>min</code> metric to denote
-minutes;
-(5) adds <code>f</code> and <code>t</code> metrics denoting frames and
-ticks, respectively;
-(6) adds alternative expression of optional <code>Fraction</code> in
-<code>Full-clock-value</code> by specifying frame count or frame
-count with subframe count.
-</p>
-</item>
-<item>
-<p>
-Interpretation of time expression is further constrained by
-parameters expressed by
-<att>ttp:clockMode</att>,
-<att>ttp:dropMode</att>,
-<att>ttp:frameRate</att>,
-<att>ttp:frameRateMultiplier</att>,
-<att>ttp:markerMode</att>,
-<att>ttp:subFrameRate</att>,
-<att>ttp:tickRate</att>, and
-<att>ttp:timeBase</att> attributes.</p>
-</item>
-<item>
-<p>Uses subset of named colors from model to which two aliases are
-added as follows: <code>magenta</code> as <code>fuchsia</code>, and <code>cyan</code>
-as <code>aqua</code>.</p>
-</item>
-<item>
-<p>If not specified, then parallel (par) container semantics apply to
-the element types specified by <specref
-ref="timing-attribute-timeContainer"/>.</p>
-</item>
-<item>
-<p>Restricts size to length specification which can be a percentage;
-adds optional second length (or percentage) for
-specifying separate horizontal and vertical scaling of glyph's EM
-square.</p>
-</item>
-<item>
-<p>Expressed in terms of writing mode relative padding properties
-rather than absolute padding properties.</p>
-</item>
-<item>
-<p>Excludes <code>blink</code> and <code>no-blink</code> values.</p>
-</item>
-<item>
-<p>Uses only one length specification instead of two, where one length
-defines distance of outline effect from nominal edge of glyph contour
-outline perpendicular to point of glyph contour. Percentage lengths
-are also added to express outline effect in relative to font size.
-Outline effects are intended to be drawn both outside of outer closed
-contours and inside of inner closed contours.</p>
-</item>
-<item>
-<p>On root element, default attribute value specified as
-<code>default</code>, which is defined in terms of whitespace
-normalization. Semantics of preservation and default normalization are
-defined in terms of presentation semantics by <specref
-ref="content-attribute-space"/>.</p>
-</item>
-<item>
-<p>Defined to be inheritable.</p>
-</item>
-</olist>
-</note>
-</div2>
-</inform-div1>
-<inform-div1 id="qa">
-<head>QA Framework Compliance</head>
-<p>This appendix specifies the compliance of this specification with the
-requirements and guidelines defined by <xspecref
-href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/">QA
-Framework Specifications Guidelines</xspecref>&nbsp;<bibref
-ref="qaf-sg"/>.</p>
-<div2>
-<head>Requirements</head>
-<table id="qa-framework-requirements-table" role="common">
-<caption>Table L-1 &ndash; QA Framework Requirements Checklist</caption>
-<col width="76%"/>
-<col width="6%" align="center"/>
-<col width="6%" align="center"/>
-<col width="6%" align="center"/>
-<col width="6%" align="center"/>
-<tbody>
-<tr>
-<td><phrase role="strong">Requirement</phrase></td>
-<td><phrase role="strong">YES</phrase></td>
-<td><phrase role="strong">NO</phrase></td>
-<td><phrase role="strong">N/A</phrase></td>
-<td><phrase role="strong">Notes</phrase></td>
-</tr>
-<tr>
-<td><xspecref href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#include-conformance-clause-principle">Requirement 01: Include a conformance
-clause</xspecref></td>
-<td><loc href="#conformance">YES</loc></td>
-<td/>
-<td/>
-<td/>
-</tr>
-<tr>
-<td><xspecref href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#define-scope-principle">Requirement 02: Define the scope.</xspecref></td>
-<td><loc href="#intro">YES</loc></td>
-<td/>
-<td/>
-<td/>
-</tr>
-<tr>
-<td><xspecref href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#implement-principle">Requirement 03: Identify who or what will implement the specification.</xspecref></td>
-<td><loc href="#conformance">YES</loc></td>
-<td/>
-<td/>
-<td/>
-</tr>
-<tr>
-<td><xspecref href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#ref-norm-principle">Requirement 04: Make a list of normative references.</xspecref></td>
-<td><loc href="#references">YES</loc></td>
-<td/>
-<td/>
-<td/>
-</tr>
-<tr>
-<td><xspecref href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#define-terms-principle">Requirement 05: Define the terms used in the normative parts of the specification.</xspecref></td>
-<td><loc href="#definitions">YES</loc></td>
-<td/>
-<td/>
-<td/>
-</tr>
-<tr>
-<td><xspecref href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#conf-label-principle">Requirement 06: Create conformance labels for each part of the conformance model.</xspecref></td>
-<td><loc href="#conformance">YES</loc></td>
-<td/>
-<td/>
-<td/>
-</tr>
-<tr>
-<td><xspecref href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#consistent-style-principle">Requirement 07: Use a consistent style for conformance requirements and explain how to distinguish them.</xspecref></td>
-<td><loc href="#conventions">YES</loc></td>
-<td/>
-<td/>
-<td/>
-</tr>
-<tr>
-<td><xspecref href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#req-opt-conf-principle">Requirement 08: Indicate which conformance requirements are mandatory, which are recommended, and which are optional.</xspecref></td>
-<td><loc href="#conventions">YES</loc></td>
-<td/>
-<td/>
-<td/>
-</tr>
-<tr>
-<td><xspecref href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#subdivide-mandatory-principle">Requirement 09: If the technology is subdivided, then indicate which subdivisions are mandatory for conformance.</xspecref></td>
-<td><loc href="#conformance">YES</loc></td>
-<td/>
-<td/>
-<td/>
-</tr>
-<tr>
-<td><xspecref href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#subdiv-constraints-principle">Requirement 10: If the technology is subdivided, then address subdivision constraints.</xspecref></td>
-<td><loc href="#conformance">YES</loc></td>
-<td/>
-<td/>
-<td/>
-</tr>
-<tr>
-<td><xspecref href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#likehood-extension-principle">Requirement 11: Address Extensibility.</xspecref></td>
-<td><loc href="#doctypes">YES</loc></td>
-<td/>
-<td/>
-<td/>
-</tr>
-<tr>
-<td><xspecref href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#deprecated-feature-principle">Requirement 12: Identify deprecated features.</xspecref></td>
-<td/>
-<td/>
-<td>N/A</td>
-<td>1</td>
-</tr>
-<tr>
-<td><xspecref href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#degree-support-principle">Requirement 13: Define how each class of product handles each deprecated feature.</xspecref></td>
-<td/>
-<td/>
-<td>N/A</td>
-<td>1</td>
-</tr>
-</tbody>
-</table>
-<note>
-<olist>
-<item>
-<p>No feature is deprecated by this version of this specification.</p>
-</item>
-</olist>
-</note>
-</div2>
-<div2>
-<head>Guidelines</head>
-<table id="qa-framework-guidelines-table" role="common">
-<caption>Table L-2 &ndash; QA Framework Guidelines Checklist</caption>
-<col width="76%"/>
-<col width="6%" align="center"/>
-<col width="6%" align="center"/>
-<col width="6%" align="center"/>
-<col width="6%" align="center"/>
-<tbody>
-<tr>
-<td><phrase role="strong">Guideline</phrase></td>
-<td><phrase role="strong">YES</phrase></td>
-<td><phrase role="strong">NO</phrase></td>
-<td><phrase role="strong">N/A</phrase></td>
-<td><phrase role="strong">Notes</phrase></td>
-</tr>
-<tr>
-<td><xspecref href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#conformance-model-gp">Good Practice 01: Define the specification's conformance model in the conformance clause.</xspecref></td>
-<td><loc href="#conformance">YES</loc></td>
-<td/>
-<td/>
-<td/>
-</tr>
-<tr>
-<td><xspecref href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#norm-informative-gp">Good Practice 02: Specify in the conformance clause how to distinguish normative from informative content.</xspecref></td>
-<td><loc href="#conventions">YES</loc></td>
-<td/>
-<td/>
-<td/>
-</tr>
-<tr>
-<td><xspecref href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#conformance-claim-gp">Good Practice 03: Provide the wording for conformance claims.</xspecref></td>
-<td><loc href="#claims">YES</loc></td>
-<td/>
-<td/>
-<td/>
-</tr>
-<tr>
-<td><xspecref href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#ics-gp">Good Practice 04: Provide an Implementation Conformance Statement Pro Forma.</xspecref></td>
-<td/>
-<td>NO</td>
-<td/>
-<td/>
-</tr>
-<tr>
-<td><xspecref href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#ics-claim-gp">Good Practice 05: Require an Implementation Conformance Statement as part of valid conformance claims.</xspecref></td>
-<td><loc href="#claims">YES</loc></td>
-<td/>
-<td/>
-</tr>
-<tr>
-<td><xspecref href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#use-example-gp">Good Practice 06: Provide examples, use cases, and graphics.</xspecref></td>
-<td><loc href="#example">YES</loc></td>
-<td/>
-<td/>
-<td/>
-</tr>
-<tr>
-<td><xspecref href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#write-sample-gp">Good Practice 07: Write sample code or tests.</xspecref></td>
-<td>YES</td>
-<td/>
-<td/>
-<td/>
-</tr>
-<tr>
-<td><xspecref href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#ref-define-practice">Good Practice 08: When imposing requirements by normative references, address conformance dependencies.</xspecref></td>
-<td><loc href="#references">YES</loc></td>
-<td/>
-<td/>
-<td>1</td>
-</tr>
-<tr>
-<td><xspecref href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#define-terms-inline-gp">Good Practice 09: Define unfamiliar terms in-line and consolidate the definitions in a glossary section.</xspecref></td>
-<td><loc href="#definitions">YES</loc></td>
-<td/>
-<td/>
-<td/>
-</tr>
-<tr>
-<td><xspecref href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#reuse-terms-gp">Good Practice 10: Use terms already defined without changing their definition.</xspecref></td>
-<td><loc href="#definitions">YES</loc></td>
-<td/>
-<td/>
-<td>2</td>
-</tr>
-<tr>
-<td><xspecref href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#formal-language-gp">Good Practice 11: Use formal languages when possible.</xspecref></td>
-<td><loc href="#schemas">YES</loc></td>
-<td/>
-<td/>
-<td/>
-</tr>
-<tr>
-<td><xspecref href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#write-assertion-gp">Good Practice 12: Write Test Assertions.</xspecref></td>
-<td/>
-<td>NO</td>
-<td/>
-<td>3</td>
-</tr>
-<tr>
-<td><xspecref href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#subdivide-foster-gp">Good Practice 13: Create subdivisions of the technology when warranted.</xspecref></td>
-<td><loc href="#conformance">YES</loc></td>
-<td/>
-<td/>
-<td/>
-</tr>
-<tr>
-<td><xspecref href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#rules-profiles-gp">Good Practice 14: If the technology is profiled, define rules for creating new profiles.</xspecref></td>
-<td><loc href="#vocabulary-profiles">YES</loc></td>
-<td/>
-<td/>
-<td/>
-</tr>
-<tr>
-<td><xspecref href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#need-option-gp">Good Practice 15:Use optional features as warranted.</xspecref></td>
-<td>YES</td>
-<td/>
-<td/>
-<td/>
-</tr>
-<tr>
-<td><xspecref href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#label-options-gp">Good Practice 16: Clearly identify optional features.</xspecref></td>
-<td>YES</td>
-<td/>
-<td/>
-<td/>
-</tr>
-<tr>
-<td><xspecref href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#constraints-gp">Good Practice 17: Indicate any limitations or constraints on optional features.</xspecref></td>
-<td>YES</td>
-<td/>
-<td/>
-<td/>
-</tr>
-<tr>
-<td><xspecref href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#extensions-prohibited-gp">Good Practice 18: If extensibility is allowed, define an extension mechanism.</xspecref></td>
-<td><loc href="#extension-vocabulary-overview">YES</loc></td>
-<td/>
-<td/>
-<td/>
-</tr>
-<tr>
-<td><xspecref href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#breaking-conformance-gp">Good Practice 19: Warn extension creators to create extensions that do not interfere with conformance.</xspecref></td>
-<td><loc href="#extension-vocabulary-overview">YES</loc></td>
-<td/>
-<td/>
-<td/>
-</tr>
-<tr>
-<td><xspecref href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#define-error-gp">Good Practice 20: Define error-handling for unknown extensions.</xspecref></td>
-<td><loc href="#conformance-processor">YES</loc></td>
-<td/>
-<td/>
-<td>4</td>
-</tr>
-<tr>
-<td><xspecref href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#workaround-gp">Good Practice 21: Explain how to avoid using a deprecated feature.</xspecref></td>
-<td/>
-<td/>
-<td>N/A</td>
-<td>5</td>
-</tr>
-<tr>
-<td><xspecref href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#obsolete-gp">Good Practice 22: Identify obsolete features.</xspecref></td>
-<td/>
-<td/>
-<td>N/A</td>
-<td>5</td>
-</tr>
-<tr>
-<td><xspecref href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#error-handling-gp">Good Practice 23: Define an error handling mechanism.</xspecref></td>
-<td><loc href="#reduced-infoset">YES</loc></td>
-<td/>
-<td/>
-<td/>
-</tr>
-</tbody>
-</table>
-<note>
-<olist>
-<item>
-<p>When making normative references to external specifications,
-specific clauses or sections are cited.</p>
-</item>
-<item>
-<p>See also <specref ref="derivation"/>.</p>
-</item>
-<item>
-<p>Test assertions and test suites will be provided prior to entering
-Proposed Recommendation (PR) phase.</p>
-</item>
-<item>
-<p>See criterion #3 in <specref
-ref="conformance-processor"/> and definition of
-<loc href="#doctypes">TTML Abstract Document Instance</loc>.</p>
-</item>
-<item>
-<p>No feature is deprecated or obsoleted by this version of this specification.</p>
-</item>
-</olist>
-</note>
-</div2>
-</inform-div1>
-<inform-div1 id="streaming">
-<head>Streaming TTML Content</head>
-<p>TTML Content is designed to support streamability by implementing the
-following properties:</p>
-<ulist>
-<item>
-<p>can be progressively encoded (i.e., does not require computing
-subsequent data prior to sending current data);</p>
-</item>
-<item>
-<p>can be progressively decoded (i.e., does not require forward
-references, but uses only reverse references when necessary);</p>
-</item>
-<item>
-<p>does not require dereferencing (and subsequent loading) of any
-resources other than TTML content (i.e., no embedded URIs);</p>
-</item>
-<item>
-<p>does not support alternative content forms (e.g., different
-language, graphics formats, time bases) in a single document;</p>
-</item>
-<item>
-<p>has timing structure compiled into inline format that makes
-possible a temporal ordering of content that follows temporal
-presentation order;</p>
-</item>
-<item>
-<p>constrains content models to prevent arbitrary nested content
-structures;</p>
-</item>
-</ulist>
-<p>One possible means by which TTML Content may be streamed is to
-partition a TTML document instance's information set into
-non-overlapping fragments, where one particular fragment, call it the
-<emph>root fragment</emph>, represents the front matter (head) of the
-document instance as well as its top level structural elements, and
-other fragments represent content whose time intervals are expected to
-be active in parallel.</p>
-<p>In applications that require arbitrary (random) entry into a
-stream, i.e., the property of being able to start reading data at an
-arbitrary data access unit, the root fragment will be repetitively
-transmitted (inserted) into the stream in order to permit a decoder to
-resynchronize and acquire sufficient structural information in the
-information set in order to interpret subsequent content
-fragments.</p>
-<p>An example of such a fragmentation of a TTML document instance is
-shown in <specref ref="fragment-streaming-graphic"/>.</p>
-<table id="fragment-streaming-graphic" role="example-images">
-<caption>Figure 3 &ndash; Fragment Streaming</caption>
-<tbody>
-<tr>
-<td><graphic id="graphic-fragment-streaming" source="images/streaming.png" alt="Fragment Streaming"/></td>
-</tr>
-</tbody>
-</table>
-<note>
-<p>This specification does not define a transport buffer model or a decoder
-capabilities model.</p>
-</note>
-</inform-div1>
-&acknowledgements;
-
-<!-- new change log format - not used yet -->
-<!--
-<inform-div1 id="change-log">
-<head>Change Log</head>
-<p>@@This paragraph will be replaced by the change log. DO NOT TOUCH@@</p>
-</inform-div1>
--->
-
-</back>
-</spec>
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+</latestloc>
+<authlist id="editors" role="editor">
+<author>
+<name>Glenn Adams</name>
+<affiliation>Cox Communications, Inc.</affiliation>
+</author>
+</authlist>
+<authlist id="contributors" role="contributor">
+<author>
+<name>Mike Dolan</name>
+<affiliation>Invited Expert</affiliation>
+</author>
+<author>
+<name>Geoff Freed</name>
+<affiliation>WGBH National Center for Accessible Media</affiliation>
+</author>
+<author>
+<name>Sean Hayes</name>
+<affiliation>Microsoft</affiliation>
+</author>
+<author>
+<name>Erik Hodge</name>
+<affiliation>RealNetworks</affiliation>
+</author>
+<author>
+<name>David Kirby</name>
+<affiliation>British Broadcasting Corporation (BBC)</affiliation>
+</author>
+<author>
+<name>Thierry Michel</name>
+<affiliation>W3C</affiliation>
+</author>
+<author>
+<name>Dave Singer</name>
+<affiliation>Apple Computer</affiliation>
+</author>
+</authlist>
+<errataloc href="https://dvcs.w3.org/hg/ttml/raw-file/default/ttml10/spec/ttml-issues.html"/>
+<translationloc href="http://www.w3.org/2003/03/Translations/byTechnology?technology=ttml11"/>
+<abstract id="abstract">
+<p>This document specifies the Timed Text Markup Language (TTML) in terms of a
+vocabulary and semantics thereof.</p>
+<p>The Timed Text Markup Language is a content type that represents
+timed text media for the purpose of interchange among authoring
+systems. Timed text is textual information that is intrinsically or
+extrinsically associated with timing information.</p>
+<p>It is intended to be used
+for the purpose of transcoding or exchanging timed text information
+among legacy distribution content formats presently in use for
+subtitling and captioning functions.</p>
+<p>In addition to being used for interchange among legacy distribution content
+formats, TTML Content may be used directly as a distribution format,
+for example, providing a standard content format to reference from a <el>&lt;track&gt;</el>
+element in an HTML5 document, or a <el>&lt;text&gt;</el> or 
+<el>&lt;textstream&gt;</el> media element in a <bibref
+ref="smil21"/> document.</p>
+</abstract>
+&status;
+<langusage><language id='en-us'>English</language></langusage>
+<revisiondesc><p>Last Modified: $Date$</p></revisiondesc>
+</header>
+<body>
+<div1 id="intro">
+<head>Introduction</head>
+<p><emph>Unless specified otherwise, this section and its sub-sections are non-normative.</emph></p>
+<p>The Timed Text Markup Language (TTML) 1.0
+provides a standardized representation of a particular subset of
+textual information with which stylistic, layout, and timing semantics are associated by
+an author or an authoring system for the purpose of interchange and processing.</p>
+<p>TTML is expressly designed to meet only a limited set of requirements
+established by <bibref ref="ttaf1-req"/>, and summarized in <specref
+ref="requirements"/>. In particular, only those requirements which service the
+need of performing interchange with existing, legacy distribution systems are
+satisfied.</p>
+<p>In addition to being used for interchange among legacy distribution content
+formats, TTML Content may be used directly as a distribution format (as implied by
+the acronym DFXP), providing, for
+example, a standard content format to reference from a <el>&lt;track&gt;</el>
+element in an HTML5 document, or a <el>&lt;text&gt;</el> or 
+<el>&lt;textstream&gt;</el> media element in a <bibref
+ref="smil21"/> document. Certain properties of TTML support
+streamability of content, as described in <specref ref="streaming"/>.</p>
+<note>
+<p>While TTML was not expressly designed for direct (embedded) integration into an
+HTML or a SMIL document instance, such integration is not precluded.</p>
+</note>
+<note>
+<p>In some contexts of use, it may be appropriate to employ
+animated content to depict sign language representations of the same content
+as expressed by a Timed Text <emph>Document Instance</emph>. This use case is not
+explicitly addressed by TTML mechanisms, but may be addressed by some
+external multimedia integration technology, such as SMIL.</p>
+</note>
+<note role="historical">
+<p>In previous drafts of this specification, TTML was referred to as DFXP (Distribution
+Format Exchange Profile). This latter term is retained for historical reasons in
+certain contexts, such as profile names and designators, and the short name
+<code>ttaf1-dfxp</code> used in URLs to refer to this specification.</p>
+</note>
+<div2 id="model">
+<head>System Model</head>
+<p>Use of TTML is intended to function in a wider context of Timed Text
+Authoring and Distribution mechanisms that are based upon the system
+model depicted in <specref ref="model-graphic"/>, wherein the Timed Text Markup Language
+serves as a bidirectional interchange format among a heterogeneous collection of
+authoring systems, and as a unidirectional interchange format to a
+heterogeneous collection of distribution formats after undergoing transcoding
+or compilation to the target distribution formats as required, and where one
+particular distribution format is TTML (labeled as "DFXP" in the figure).</p>
+<table id="model-graphic" role="example-images">
+<caption>Figure 1 &ndash; System Model</caption>
+<tbody>
+<tr>
+<td><graphic id="graphic-model" source="images/model.png" alt="System Model"/></td>
+</tr>
+</tbody>
+</table>
+</div2>
+<div2 id="example">
+<head>Document Example</head>
+<p>A TTML <emph>Document Instance</emph> consists of a <el>tt</el> document element that contains
+a header and a body, where the header specifies document level metadata, styling
+definitions and layout definitions, and the body specifies text content intermixed
+with references to style and layout information and inline styling and timing information.</p>
+<table id="ttml-example-document-structure" role="example">
+<caption>Example Fragment &ndash; TTML Document Structure</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;tt xml:lang="" xmlns="http://www.w3.org/ns/ttml"&gt;
+  &lt;head&gt;
+    &lt;metadata/&gt;
+    &lt;styling/&gt;
+    &lt;layout/&gt;
+  &lt;/head&gt;
+  &lt;body/&gt;
+&lt;/tt&gt;
+</eg>
+</td></tr>
+</tbody>
+</table>
+<p>Document level metadata may specify a document title, description,
+and copyright information. In addition, arbitrary metadata drawn from
+other namespaces may be specified.</p>
+<table id="ttml-example-metadata" role="example">
+<caption>Example Fragment &ndash; TTML Metadata</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;metadata xmlns:ttm="http://www.w3.org/ns/ttml#metadata"&gt;
+  &lt;ttm:title&gt;Timed Text TTML Example&lt;/ttm:title&gt;
+  &lt;ttm:copyright&gt;The Authors (c) 2006&lt;/ttm:copyright&gt;
+&lt;/metadata&gt;
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p>Styling information may be specified in the form of style specification
+definitions that are referenced by layout and content information,
+specified inline with content information, or both.</p>
+<p>In <specref ref="ttml-example-styling"/>, four style sets of specifications
+are defined, with one set serving as a collection of default styles.</p>
+<table id="ttml-example-styling" role="example">
+<caption>Example Fragment &ndash; TTML Styling</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;styling xmlns:tts="http://www.w3.org/ns/ttml#styling"&gt;
+  &lt;!-- s1 specifies default color, font, and text alignment --&gt;
+  &lt;style xml:id="s1"
+    tts:color="white"
+    tts:fontFamily="proportionalSansSerif"
+    tts:fontSize="22px"
+    tts:textAlign="center"
+  /&gt;
+  &lt;!-- alternative using yellow text but otherwise the same as style s1 --&gt;
+  &lt;style xml:id="s2" style="s1" tts:color="yellow"/&gt;
+  &lt;!-- a style based on s1 but justified to the right --&gt;
+  &lt;style xml:id="s1Right" style="s1" tts:textAlign="end" /&gt;     
+  &lt;!-- a style based on s2 but justified to the left --&gt;
+  &lt;style xml:id="s2Left" style="s2" tts:textAlign="start" /&gt;
+&lt;/styling&gt;
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p>Layout information defines one or more regions into which content
+is intended to be presented. A region definition may reference one or
+more sets of style specifications in order to permit content flowed in the
+region to inherit from these styles.
+In <specref ref="ttml-example-layout"/>, the region definition makes
+reference to style specification <code>s1</code> augmented by specific inline
+styles which, together, allow content flowed into the region to inherit
+from the region's styles (in the case
+that a style is not already explicitly specified on content or inherited
+via the content hierarchy.)</p>
+<table id="ttml-example-layout" role="example">
+<caption>Example Fragment &ndash; TTML Layout</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;layout xmlns:tts="http://www.w3.org/ns/ttml#styling"&gt;
+  &lt;region xml:id="subtitleArea"
+    style="s1"
+    tts:extent="560px 62px"
+    tts:padding="5px 3px"
+    tts:backgroundColor="black"
+    tts:displayAlign="after"
+  /&gt;
+&lt;/layout&gt;  
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p>The content of a <emph>Document Instance</emph> is expressed in its
+body, which is organized in terms of block and inline text elements.
+The hierarchical organization of content elements serves a primary role in
+determining both spatial and temporal relationships. For example, in
+<specref ref="ttml-example-body"/>, each paragraph (<el>p</el> element)
+is flowed into its target region in the specified lexical order; furthermore,
+the active time interval of each paragraph is timed in accordance to its
+parent or sibling according to the applicable time containment semantics &mdash;
+in this case, the division parent is interpreted (by default) as a parallel time
+container.</p>
+<table id="ttml-example-body" role="example">
+<caption>Example Fragment &ndash; TTML Body</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;body region="subtitleArea"&gt;
+  &lt;div&gt;
+    &lt;p xml:id="subtitle1" begin="0.76s" end="3.45s"&gt;
+      It seems a paradox, does it not,
+    &lt;/p&gt;
+    &lt;p xml:id="subtitle2" begin="5.0s" end="10.0s"&gt;
+      that the image formed on&lt;br/&gt;
+      the Retina should be inverted?
+    &lt;/p&gt;
+    &lt;p xml:id="subtitle3" begin="10.0s" end="16.0s" style="s2"&gt;
+      It is puzzling, why is it&lt;br/&gt;
+      we do not see things upside-down?
+    &lt;/p&gt;
+    &lt;p xml:id="subtitle4" begin="17.2s" end="23.0s"&gt;
+      You have never heard the Theory,&lt;br/&gt;
+      then, that the Brain also is inverted?
+    &lt;/p&gt;
+    &lt;p xml:id="subtitle5" begin="23.0s" end="27.0s" style="s2"&gt;
+      No indeed! What a beautiful fact!
+    &lt;/p&gt;
+    &lt;p xml:id="subtitle6a" begin="28.0s" end="34.6s" style="s2Left"&gt;
+      But how is it proved?
+    &lt;/p&gt;
+    &lt;p xml:id="subtitle6b" begin="28.0s" end="34.6s" style="s1Right"&gt;
+      Thus: what we call
+    &lt;/p&gt;
+    &lt;p xml:id="subtitle7" begin="34.6s" end="45.0s" style="s1Right"&gt;
+      the vertex of the Brain&lt;br/&gt;
+      is really its base
+    &lt;/p&gt;
+    &lt;p xml:id="subtitle8" begin="45.0s" end="52.0s" style="s1Right"&gt;
+      and what we call its base&lt;br/&gt;
+      is really its vertex,
+    &lt;/p&gt;
+    &lt;p xml:id="subtitle9a" begin="53.5s" end="58.7s"&gt;
+      it is simply a question of nomenclature.
+    &lt;/p&gt;
+    &lt;p xml:id="subtitle9b" begin="53.5s" end="58.7s" style="s2"&gt;
+      How truly delightful!
+    &lt;/p&gt;
+  &lt;/div&gt;    
+&lt;/body&gt;
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p>The first subtitle <specref ref="ttml-example-subtitle-1"/> is
+presented during the time interval 0.76 to 3.45 seconds.
+This
+subtitle inherits its font family, font size,
+foreground color, and text alignment from the region into which it is
+presented. Since no region is explicitly specified on the paragraph,
+the nearest ancestor that specifies a region determines the
+targeted region. Note also that content is presented
+at the bottom (after edge) of the containing region due to the <code>tts:displayAlign="after"</code>
+being specified on the region definition.</p>
+<note role="explanation">
+<p>The notation "[<emph>X</emph>,<emph>Y</emph>]" denotes a closed
+interval from <emph>X</emph> to <emph>Y</emph>, including
+<emph>X</emph> and <emph>Y</emph>;
+"[<emph>X</emph>,<emph>Y</emph>)" denotes a right half-open
+interval from <emph>X</emph> to <emph>Y</emph>, including
+<emph>X</emph> but not including <emph>Y</emph>;
+"(<emph>X</emph>,<emph>Y</emph>]" denotes a left half-open
+interval from <emph>X</emph> to <emph>Y</emph>, not including
+<emph>X</emph> but including <emph>Y</emph>;
+"(<emph>X</emph>,<emph>Y</emph>)" denotes an open
+interval from <emph>X</emph> to <emph>Y</emph>, not including
+<emph>X</emph> or <emph>Y</emph>.
+</p>
+</note>
+<note role="explanation">
+<p>In this example, the <el>p</el> element is used as a presentational
+element rather than as a semantic element, i.e., as a linguistic paragraph.
+It is up to an author to determine which TTML elements are used to convey
+the intended meaning. For instance, this example could be written to use
+timing on <el>span</el> elements in order to preserve the integrity of
+semantic paragraphs.</p>
+</note>
+<table id="ttml-example-subtitle-1" role="example-images">
+<caption>Subtitle 1 &ndash; Time Interval [0.76, 3.45)</caption>
+<tbody>
+<tr>
+<td><graphic source="images/subtitle1.png" alt="Subtitle 1"/></td>
+</tr>
+</tbody>
+</table>
+<p>The second subtitle continues with the default style, except that it contains
+two lines of text with an intervening author-specified line break. Note the effects of
+the use of <code>tts:textAlign="center"</code> to specify the paragraph's alignment
+in the inline progression direction.</p>
+<table id="ttml-example-subtitle-2" role="example-images">
+<caption>Subtitle 2 &ndash; Time Interval [5.0, 10.0)</caption>
+<tbody>
+<tr>
+<td><graphic source="images/subtitle2.png" alt="Subtitle 2"/></td>
+</tr>
+</tbody>
+</table>
+<p>The third subtitle continues, using a variant style which overrides the default style's
+foreground color with a different color.</p>
+<table id="ttml-example-subtitle-3" role="example-images">
+<caption>Subtitle 3 &ndash; Time Interval [10.0, 16.0)</caption>
+<tbody>
+<tr>
+<td><graphic source="images/subtitle3.png" alt="Subtitle 3"/></td>
+</tr>
+</tbody>
+</table>
+<p>The fourth subtitle reverts to the default style.</p>
+<table id="ttml-example-subtitle-4" role="example-images">
+<caption>Subtitle 4 &ndash; Time Interval [17.2, 23.0)</caption>
+<tbody>
+<tr>
+<td><graphic source="images/subtitle4.png" alt="Subtitle 4"/></td>
+</tr>
+</tbody>
+</table>
+<p>The fifth subtitle continues, again using a variant style which
+overrides the default style's foreground color with a different color.</p>
+<table id="ttml-example-subtitle-5" role="example-images">
+<caption>Subtitle 5 &ndash; Time Interval [23.0, 27.0)</caption>
+<tbody>
+<tr>
+<td><graphic source="images/subtitle5.png" alt="Subtitle 5"/></td>
+</tr>
+</tbody>
+</table>
+<p>During the next active time interval, two distinct subtitles are simultaneously active, with
+the paragraphs expressing each subtitle using different styles that override color and paragraph
+text alignment of the default style. Note that the flow order is determined by the lexical
+order of elements as they appear in the content hierarchy.</p>
+<table id="ttml-example-subtitle-6" role="example-images">
+<caption>Subtitles 6a and 6b &ndash; Time Interval [28.0, 34.6)</caption>
+<tbody>
+<tr>
+<td><graphic source="images/subtitle6.png" alt="Subtitles 6a and 6b"/></td>
+</tr>
+</tbody>
+</table>
+<p>The next subtitle is specified in a similar manner using
+a style override to give the paragraph right (end) justification in the
+inline progression direction.</p>
+<table id="ttml-example-subtitle-7" role="example-images">
+<caption>Subtitle 7 &ndash; Time Interval [34.6, 45.0)</caption>
+<tbody>
+<tr>
+<td><graphic source="images/subtitle7.png" alt="Subtitles 7a and 7b"/></td>
+</tr>
+</tbody>
+</table>
+<p>The eighth subtitle uses the same style override as the previous
+subtitle in order to maintain the right (end) justification of the
+paragraph.</p>
+<table id="ttml-example-subtitle-8" role="example-images">
+<caption>Subtitle 8 &ndash; Time Interval [47.3, 49.0)</caption>
+<tbody>
+<tr>
+<td><graphic source="images/subtitle8.png" alt="Subtitle 8"/></td>
+</tr>
+</tbody>
+</table>
+<p>During the final (ninth) active time interval, two distinct
+subtitles are again simultaneously active, but with a different
+style applied to the second paragraph to override the default color.
+Note that the flow order is determined by the lexical order of
+elements as they appear in the content hierarchy.</p>
+<table id="ttml-example-subtitle-9" role="example-images">
+<caption>Subtitles 9a and 9b &ndash; Time Interval [53.5, 58.7)</caption>
+<tbody>
+<tr>
+<td><graphic source="images/subtitle9.png" alt="Subtitles 9a and 9b"/></td>
+</tr>
+</tbody>
+</table>
+<p>The examples shown above demonstrate the primary types of information that may
+be authored using TTML: metadata, styling, layout, timing, and content. In typical cases,
+styling and layout information are separately specified in a <emph>Document Instance</emph>. Content information
+is expressed in a hierarchical fashion that embodies the organization of both spatial (flow) and
+timing information. Content makes direct or indirect references to styling and layout information
+and may specify inline overrides to styling.</p>
+</div2>
+</div1>
+<div1 id="definitions">
+<head>Definitions</head>
+<div2 id="acronyms">
+<head>Acronyms</head>
+<glist role="acronyms">
+<gitem>
+<label>DFXP</label>
+<def>
+<p>Distribution Format Exchange Profile</p>
+</def>
+</gitem>
+<gitem>
+<label>TT</label>
+<def>
+<p>Timed Text</p>
+</def>
+</gitem>
+<gitem>
+<label>TTML</label>
+<def>
+<p>Timed Text Markup Language</p>
+</def>
+</gitem>
+<gitem>
+<label>TTAF</label>
+<def>
+<p>Timed Text Authoring Format</p>
+</def>
+</gitem>
+<gitem>
+<label>TTWG</label>
+<def>
+<p>Timed Text Working Group</p>
+</def>
+</gitem>
+</glist>
+</div2>
+<div2 id="terms">
+<head>Terminology</head>
+<glist>
+<gitem>
+<label>Abstract Document Instance</label>
+<def>
+<p>An instance of an abstract data set as represented by a
+<emph>Reduced XML Infoset</emph>.</p>
+</def>
+</gitem>
+<gitem>
+<label>Abstract Document Type</label>
+<def>
+<p>A set of constraints that defines a class of <emph>XML Information
+Sets</emph> <bibref ref="infoset"/>.</p>
+</def>
+</gitem>
+<gitem>
+<label>Attribute Information Item</label>
+<def>
+<p>Each specified or defaulted attribute  of an XML document corresponds with an attribute information
+item as defined by <bibref ref="infoset"/>, &sect;2.3.</p>
+</def>
+</gitem>
+<gitem>
+<label>Character Information Item</label>
+<def>
+<p>Each data character appearing in an XML document corresponds with a character information
+item as defined by <bibref ref="infoset"/>, &sect;2.6.</p>
+</def>
+</gitem>
+<gitem>
+<label>Computed Cell Size</label>
+<def>
+<p>The size (extent) of a cell computed by dividing the width of the <emph>Root Container
+Region</emph> by the column count, i.e., the number of cells in the horizontal axis, and by dividing
+the height of the <emph>Root Container Region</emph> by the row count, i.e., the number of cells in the vertical
+axis, where the column and row counts are determined by the <att>ttp:cellResolution</att> parameter attribute.</p>
+</def>
+</gitem>
+<gitem>
+<label>Content Processor</label>
+<def>
+<p>A processing system capable of importing (receiving) Timed Text Markup Language
+content for the purpose of transforming, presenting, or otherwise processing the content.</p>
+</def>
+</gitem>
+<gitem>
+<label>Content Profile</label>
+<def>
+<p>A collection of features and extensions that are (or may be) employed by
+Timed Text Markup Language content.</p>
+</def>
+</gitem>
+<gitem>
+<label>Content Region</label>
+<def>
+<p>A logical region into which rendered content is placed when modeling or
+performing presentation processing.</p>
+</def>
+</gitem>
+<gitem>
+<label>Document Instance</label>
+<def>
+<p>A concrete realization of a Timed Text Markup Language document, where the concrete form
+is specific to the context of reference. For example, a sequence of bytes that represents an
+XML serialization of a Timed Text document, an internal, parsed representation of such a
+Timed Text document, etc.</p>
+</def>
+</gitem>
+<gitem>
+<label>Document Interchange Context</label>
+<def>
+<p>The implied context or environment external to a <emph>Content Processor</emph> in
+which document interchange occurs, and in which out-of-band protocols or specifications
+may define certain behavioral defaults, such as an implied <emph>Content Profile</emph>.</p>
+</def>
+</gitem>
+<gitem>
+<label>Document Processing Context</label>
+<def>
+<p>The implied context or environment internal to a <emph>Content Processor</emph> in
+which document processing occurs, and in which out-of-band protocols or specifications
+may define certain behavioral defaults, such as the establishment or creation of a
+<emph>Synthetic Document Syncbase</emph>.</p>
+</def>
+</gitem>
+<gitem>
+<label>Element Information Item</label>
+<def>
+<p>Each element appearing in an XML document corresponds with an element information
+item as defined by <bibref ref="infoset"/>, &sect;2.2.</p>
+</def>
+</gitem>
+<gitem>
+<label>Exchange Profile</label>
+<def>
+<p>A content profile that serves a set of needs
+for content interchange.</p>
+</def>
+</gitem>
+<gitem>
+<label>Extension</label>
+<def>
+<p>A syntactic or semantic expression or capability that is defined and
+labeled (using a extension designation) in another (public or private)
+specification.</p>
+</def>
+</gitem>
+<gitem>
+<label>Feature</label>
+<def>
+<p>A syntactic or semantic expression or capability that is defined and
+labeled (using a feature designation) in this specification (or a
+future revision of this specification).</p>
+</def>
+</gitem>
+<gitem>
+<label>Presentation Processor</label>
+<def>
+<p>A <emph>Content Processor</emph> which purpose is to layout, format, and render,
+i.e., to present, <emph>Timed Text Markup Language</emph> content by applying the presentation semantics
+defined in this specification.</p>
+</def>
+</gitem>
+<gitem>
+<label>Processor</label>
+<def>
+<p>See <emph>Content Processor</emph>.</p>
+</def>
+</gitem>
+<gitem>
+<label>Processor Profile</label>
+<def>
+<p>A collection of features and extensions that must or may be implemented (supported) by
+a content processor.</p>
+</def>
+</gitem>
+<gitem>
+<label>Profile Definition Document</label>
+<def>
+<p>A document that defines a specific collection of features and extensions
+for which support is required or optional in a recipient content
+processor.</p>
+</def>
+</gitem>
+<gitem>
+<label>Region</label>
+<def>
+<p>A logical construct that models authorial intention regarding
+desired or potential presentation processing, and which is represented as
+a rectangular area of a presentation surface into which content
+is composed and rendered during presentation processing.</p>
+</def>
+</gitem>
+<gitem>
+<label>Reduced XML Infoset</label>
+<def>
+<p>An XML Information Set <bibref ref="infoset"/> that satisfies the
+constraints specify by <specref ref="reduced-infoset"/>.</p>
+</def>
+</gitem>
+<gitem>
+<label>Related Media Object</label>
+<def>
+<p>A (possibly null) media object associated with or otherwise related
+to a <emph>Document Instance</emph>. For example, an aggregate audio/video media
+object for which a <emph>Document Instance</emph> provides caption or subtitle
+information, and with which that <emph>Document Instance</emph> is associated.</p>
+</def>
+</gitem>
+<gitem>
+<label>Related Media Object Region</label>
+<def>
+<p>When a non-null <emph>Related Media Object</emph> exists, the region in which
+a presentation processor presents this media object.</p>
+</def>
+</gitem>
+<gitem>
+<label>Root Container Region</label>
+<def>
+<p>A logical region that establishes a coordinate system into which
+<emph>Document Instance</emph> content regions are placed and optionally clipped.</p>
+</def>
+</gitem>
+<gitem>
+<label>Root Temporal Extent</label>
+<def>
+<p>
+The temporal extent (interval) defined by the temporal beginning and ending of a <emph>Document Instance</emph> in relationship with some external application or presentation context.
+</p>
+</def>
+</gitem>
+<gitem>
+<label>SMPTE Time Code</label>
+<def>
+<p>A time code whose format and semantics are established by <bibref ref="smpte12m"/>,
+which may be embedded into or otherwise associated with media content, such
+as a broadcast audio/video stream.</p>
+</def>
+</gitem>
+<gitem>
+<label>Synthetic Document Syncbase</label>
+<def>
+<p>A document level <xspecref href="http://www.w3.org/TR/2005/REC-SMIL2-20051213/smil-timing.html#Timing-Syncbases">syncbase</xspecref>
+<bibref ref="smil21"/>, &sect; 10.7.1, synthesized or otherwise established by
+the <emph>Document Processing Context</emph> in accordance with the
+<emph>Related Media Object</emph> or other processing criteria.</p>
+</def>
+</gitem>
+<gitem>
+<label>Synthetic SMPTE Document Syncbase</label>
+<def>
+<p>A <emph>Synthetic Document Syncbase</emph> constructed from <emph>SMPTE Time
+Code</emph> values embedded in or associated with the <emph>Related Media Object</emph> or
+otherwise determined by the <emph>Document Processing Context</emph>.</p>
+</def>
+</gitem>
+<gitem>
+<label>Timed Text</label>
+<def>
+<p>Textual information that is intrinsically or extrinsically
+associated with timing information.</p>
+</def>
+</gitem>
+<gitem>
+<label>Timed Text Markup Language</label>
+<def>
+<p>A content type that represents timed text media for the purpose of
+interchange among authoring systems.</p>
+</def>
+</gitem>
+<gitem>
+<label>Timed Text Authoring System</label>
+<def>
+<p>A content authoring system capable of importing and exporting
+Timed Text Markup Language content.</p>
+</def>
+</gitem>
+<gitem>
+<label>Transformation Processor</label>
+<def>
+<p>A <emph>Content Processor</emph> which purpose is to transform or otherwise rewrite
+<emph>Timed Text Markup Language</emph> content to either <emph>Timed Text Markup Language</emph>
+or to another (arbitrary) content format. An example of the first is a processor that removes
+or rewrites TTML features so as to conform to a profile of TTML. An example of the latter is
+a processor that translates TTML into a completely different timed text format. Because this
+specification does not otherwise define a target profile or format for transformation processing,
+no further transformation semantics are defined by this specification.</p>
+</def>
+</gitem>
+<gitem>
+<label>Valid Abstract Document Instance</label>
+<def>
+<p>An <emph>Abstract Document Instance</emph> which has been assessed for validity
+and found to be valid as defined by <specref ref="doctypes"/>.</p>
+</def>
+</gitem>
+</glist>
+</div2>
+<div2 id="conventions">
+<head>Documentation Conventions</head>
+<p>Within normative prose in this specification, the words
+<emph>may</emph>, <emph>should</emph>, and <emph>must</emph> are
+defined as follows:</p>
+<glist role="conformance-keywords">
+<gitem>
+<label>may</label>
+<def>
+<p>Conforming documents and/or TTML processors are permitted to,
+but need not behave as described. </p>
+</def>
+</gitem>
+<gitem>
+<label>should</label>
+<def>
+<p>Conforming documents and/or TTML processors are strongly
+recommended to, but need not behave as described.</p>
+</def>
+</gitem>
+<gitem>
+<label>must</label>
+<def>
+<p>Conforming documents and/or TTML processors are required
+to behave as described; otherwise, they are in error. </p>
+</def>
+</gitem>
+</glist>
+
+<p>If normative specification language takes an imperative form,
+then it is to be treated as if the term <phrase role="strong">must</phrase>
+applies. Furthermore, if normative language takes a declarative form,
+and this language is governed by <phrase role="strong">must</phrase>,
+then it is also to be treated as if the term <phrase role="strong">must</phrase>
+applies.</p>
+<note role="example">
+<p>For example, the phrases "treat X as an error" and "consider X
+as an error" are to be read as mandatory requirements in the context of use. Similarly, if the specification
+prose is "X must apply", "X applies", or "X is mandatory", and "X" is further defined as "X is Y and Z",
+then, by transitive closure, this last declarative phrase is to be read as "Y is mandatory" and
+"Z is mandatory" in the context of use.</p>
+</note>
+<p>All normative syntactic definitions of XML representations and
+other related terms are depicted with a light yellow-orange background color
+and labeled as "XML Representation" or "Syntax Representation", such
+as in the following:</p>
+<table id="elt-syntax-example" role="syntax">
+<caption>XML Representation &ndash; Element Information Item: example</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;example
+  <phrase role="reqattr">count</phrase> = integer
+  size = (<emph>large</emph>|<emph>medium</emph>|<emph>small</emph>) : medium&gt;
+  <emph>Content:</emph> (all | any*)
+&lt;/example&gt;
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p>In an XML representation, bold-face attribute names (e.g. <phrase
+role="strong">count</phrase> above) indicate a required attribute
+information item, and the rest are optional. Where an attribute
+information item has an enumerated type definition, the values are
+shown separated by vertical bars, as for <code>size</code> above; if
+there is a default value, it is shown following a colon. Where an
+attribute information item has a built-in simple type definition
+defined in <bibref ref="xsd-2"/>, a hyperlink to its definition
+therein is given.</p>
+<p>The allowed content of the information item is shown as a grammar
+fragment, using the Kleene operators <code>?</code>, <code>*</code>
+and <code>+</code>. Each element name therein is a hyperlink to its
+own illustration.</p>
+<p>The term linear white-space (LWSP) is to be interpreted as a non-empty sequence of
+SPACE (U+0020), TAB (U+0009), CARRIAGE RETURN (U+000D), or LINE FEED (U+000A),
+which corresponds to production [3] <code>S</code> as defined by <bibref ref="xml10"/>.</p>
+<p>All content of this specification that is not explicitly marked as
+non-normative is considered to be normative. If a section or appendix
+header contains the expression "Non-Normative", then the entirety
+of the section or appendix is considered non-normative.</p>
+<p>All paragraphs marked as a <phrase role="strong">Note</phrase> are considered non-normative.</p>
+<p>Example code fragments are depicted with a light blue-green
+background color and labeled as "Example Fragment", such as in
+the following:</p>
+<table id="example-fragment-1" role="example">
+<caption>Example Fragment &ndash; Sample</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;tt xml:lang="" xmlns="http://www.w3.org/ns/ttml"&gt;
+  &lt;head&gt;
+    &lt;metadata/&gt;
+    &lt;styling/&gt;
+    &lt;layout/&gt;
+  &lt;/head&gt;
+  &lt;body/&gt;
+&lt;/tt&gt;
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+</div2>
+</div1>
+<div1 id="conformance">
+<head>Conformance</head>
+<p>This section specifies the general conformance requirements for
+TTML Content and processors.</p>
+<div2 id="conformance-content">
+<head>Content Conformance</head>
+<p>A TTML <emph>Document Instance</emph> conforms to this specification if the following criteria are
+satisfied:</p>
+<olist>
+<item>
+<p>When transporting a <emph>Document Instance</emph> in a <emph>Document Interchange Context</emph> in which a
+Media Type <bibref ref="media-types"/> identifies the content type of the interchanged <emph>Document Instance</emph>, then the specified media type is
+<code>application/ttml+xml</code> in conformance with <bibref
+ref="xml-media"/> &sect; 7, with which an optional
+<code>profile</code> parameter may appear, the value of which
+conforms to
+a profile designator as
+defined by
+<specref ref="vocabulary-profiles"/>.</p>
+</item>
+<item>
+<p>The <emph>Document Instance</emph> is or can be represented as a Reduced XML
+Infoset as defined by <specref ref="reduced-infoset"/>.</p>
+</item>
+<item>
+<p>The Reduced XML
+Infoset that corresponds to the <emph>Document Instance</emph> is or can
+be associated with one of the <emph>Abstract Document Types</emph> defined by
+<specref ref="doctypes"/>.</p>
+</item>
+<item>
+<p>The <emph>Reduced XML Infoset</emph> that corresponds to the <emph>Document Instance</emph> is a
+<emph>Valid Abstract Document Instance</emph> of the associated
+<emph>Abstract Document Type</emph>.</p>
+</item>
+<item>
+<p>The <emph>Reduced XML Infoset</emph> satisfies all additional mandatory syntactic and
+semantic constraints defined by this specification. In addition, this Infoset
+should satisfy the web content accessibility guidelines specified by
+<bibref ref="wcag"/>.</p>
+</item>
+</olist>
+</div2>
+<div2 id="conformance-processor">
+<head>Processor Conformance</head>
+<div3 id="conformance-generic-processor">
+<head>Generic Processor Conformance</head>
+<p>A TTML <emph>Content Processor</emph> conforms to this specification if the following
+generic processor criteria are
+satisfied:</p>
+<olist>
+<item>
+<p>The processor provides at least one mechanism for notionally
+instantiating a Reduced XML
+Infoset representation of a conformant <emph>Document Instance</emph>.</p>
+</item>
+<item>
+<p>If a process does or can perform validation of a candidate 
+<emph>Document Instance</emph>, then it provides at least one mechanism to
+implicitly or explicitly associate the
+<emph>Reduced XML Infoset</emph> representation
+of a conformant <emph>Document Instance</emph> with one of the
+<emph>Abstract Document Types</emph> defined by
+<specref ref="doctypes"/>.</p>
+</item>
+<item>
+<p>The processor does not <emph>a priori</emph> reject or abort the
+processing of a conformant <emph>Document Instance</emph>
+unless the processor does not support some required
+(mandatory) feature specified or implied by a TTML profile
+declared to apply to the <emph>Document Instance</emph>.</p>
+</item>
+<item>
+<p>The processor supports all mandatory processing semantics defined by this specification.</p>
+<note role="clarification">
+<p>The phrase <emph>mandatory semantics</emph> refers to all explicit use of the conformance
+key phrases <phrase role ="strong">must</phrase> and <phrase role="strong">must not</phrase> as well as any
+declarative statement that can be reasonably inferred from such key phrases. For example, these
+mandatory semantics include support for all features marked as mandatory in <specref ref="feature-support"/>.</p>
+</note>
+</item>
+<item>
+<p>If the processor supports some optional processing semantics defined by this specification,
+then it does so in a manner consistent with the defined semantics.</p>
+<note role="clarification">
+<p>The phrase <emph>optional semantics</emph> refers to all explicit use of the conformance
+key phrases <phrase role ="strong">should</phrase>, <phrase role="strong">should not</phrase>,
+<phrase role ="strong">may</phrase>, and <phrase role="strong">may not</phrase>,
+as well as any declarative statement that can be reasonably inferred from such key phrases. For example, these
+optional semantics include support for all features marked as optional in <specref ref="feature-support"/>.</p>
+</note>
+</item>
+</olist>
+</div3>
+<div3 id="conformance-transformation-processor">
+<head>Transformation Processor Conformance</head>
+<p>A TTML <emph>Content Processor</emph> is a conformant TTML <emph>Transformation Processor</emph> if
+the following criteria are satisfied:</p>
+<olist>
+<item>
+<p>The processor satisfies all requirements specified by
+<specref ref="conformance-generic-processor"/>.</p>
+</item>
+<item>
+<p>The processor supports the DFXP Transformation profile as specified
+by <specref ref="profile-dfxp-transformation"/>.</p>
+</item>
+</olist>
+</div3>
+<div3 id="conformance-presentation-processor">
+<head>Presentation Processor Conformance</head>
+<p>A TTML <emph>Content Processor</emph> is a conformant TTML <emph>Presentation Processor</emph> if
+the following criteria are satisfied:</p>
+<olist>
+<item>
+<p>The processor satisfies all requirements specified by
+<specref ref="conformance-generic-processor"/>.</p>
+</item>
+<item>
+<p>The processor supports the DFXP Presentation profile as specified
+by <specref ref="profile-dfxp-presentation"/>.</p>
+</item>
+</olist>
+</div3>
+</div2>
+<div2 id="claims">
+<head>Claims</head>
+<p>Any claim of compliance with respect to the conformance of a TTML <emph>Document Instance</emph> or
+<emph>Content Processor</emph> must make
+reference to an implementation compliance statement (ICS).</p>
+<p>An implementation compliance statement must identify all mandatory
+and optional features of this specification that are satisfied by the
+document instance or the content processor implementation. In particular, the statement must
+identify the utilized or supported TTML vocabulary profile(s) as
+defined by <specref ref="vocabulary-profiles"/>, and, if a subset or
+superset profile is used or supported, then what features are excluded
+or included in the subset or superset profile.</p>
+<p>A <emph>Document Instance</emph> for which a compliance claim is made
+must specify
+either (1)
+a <att>ttp:profile</att> attribute on its root
+<el>tt</el>
+element
+as defined by <specref ref="parameter-attribute-profile"/>
+or (2)
+a <el>ttp:profile</el> element as a child of the
+<el>head</el> element as defined by
+<specref ref="parameter-vocabulary-profile"/>.</p>
+</div2>
+</div1>
+<div1 id="doctypes">
+<head>Document Types</head>
+<p>This section defines the following TTML <emph>Abstract Document Types</emph>:</p>
+<ulist>
+<item><p><specref ref="ttml-content-doctype"/></p></item>
+</ulist>
+<p>Each <emph>Abstract Document Type</emph> consists of the following constraints:</p>
+<ulist>
+<item><p>a non-empty collection of element types, where each element type consists of a name,
+a (possibly empty) collection of attributes, and a content specification</p></item>
+<item><p>a non-empty collection of element types that may appear as the document element</p></item>
+</ulist>
+<p>An <emph>Abstract Document Instance</emph> may be assessed in terms of validity,
+and is considered to be a <emph>Valid Abstract Document Instance</emph> if it
+satisfies the following condition: if after</p>
+<olist>
+<item>
+<p>pruning all element information
+items whose names are not members of the collection of element types defined
+by the associated <emph>Abstract Document Type</emph>, then</p>
+</item>
+<item>
+<p>pruning character
+information item children from any remaining element in case that all
+character children of the element denote XML whitespace characters and the element's type
+is defined as empty in the associated <emph>Abstract Document Type</emph>, and then</p>
+</item>
+<item>
+<p>pruning all attribute
+information items having expanded names such that the namespace URI of the
+expanded names are not listed in <specref
+ref="namespace-vocab-table"/>,</p>
+</item>
+</olist>
+<p>then the document element is one of the document
+element types permitted by the associated <emph>Abstract Document Type</emph>,
+the descendants of the document
+element satisfy their respective element type's content
+specifications, all required attributes are present, and the declared
+value of each attribute satisfies the type declared by the
+associated <emph>Abstract Document Type</emph>.</p>
+<note>
+<p>While a conformant processor may not <emph>a priori</emph> reject a
+conformant <emph>Document Instance</emph> that adheres to a
+supported content profile, a given <emph>Document Instance</emph> may be
+constrained by the author or authoring tool to satisfy a more
+restrictive definition of validity.</p>
+</note>
+<div2 id="ttml-content-doctype">
+<head>TTML Content</head>
+<p>TTML Content is an <emph>Abstract Document Type</emph> of a profile of the Timed Text Markup Language intended
+to be used for interchange among distribution systems. This document type
+is defined in terms of the
+element and attribute vocabulary
+specified in <specref ref="vocabulary"/>.</p>
+<p>This specification references two types of schemas that may be used to validate a superset/subset
+of conformant TTML Content <emph>Document Instances</emph>:</p>
+<ulist>
+<item><p><specref ref="ttml-schema-rnc"/></p></item>
+<item><p><specref ref="ttml-schema-xsd"/></p></item>
+</ulist>
+<p>The (root) document element of a TTML Content <emph>Document Instance</emph> must be a
+<el>tt</el> element, as defined by <specref
+ref="document-structure-vocabulary-tt"/>.</p>
+<note role="clarification">
+<p>The schemas referenced by this specification do not validate all syntactic constraints
+defined by this specification, and, as such, represent a superset of conformant
+TTML Content. In particular, performing validation with one of the above
+referenced schemas may result in a <emph>false positive</emph> indication of validity.
+For example, both the RNC and XSD schemas specify
+that a <att>tts:fontFamily</att> attribute must
+satisfy the <code>xs:string</code> XSD data type; however, this data type is a superset
+of the values permitted to be used with the <att>tts:fontFamily</att> attribute.</p>
+<p>In addition, the RNC schema may produce a <emph>false negative</emph>
+indication of validity when using the <att>xml:id</att> attribute with an element in
+a foreign namespace, thus representing a subset of conformant TTML Content. This is
+due to a specific limitation in expressing wildcard patterns involving <code>xsd:ID</code>
+typed attributes in Relax NG schemas. Note that this specification defines the
+formal validity of a <emph>Document Instance</emph> to be based on an <emph>Abstract Document Instance</emph> from
+which all foreign namespace elements and attributes have been removed. Therefore, the
+exceptional reporting of this false negative does not impact the formal assessment
+of <emph>Document Instance</emph> validity.</p>
+</note>
+</div2>
+</div1>
+<div1 id="vocabulary">
+<head>Vocabulary</head>
+<p>This section defines the
+namespaces, profiles, and vocabulary (as an element and attribute
+catalog) of the Timed Text Markup Language (TTML) as follows:</p>
+<ulist>
+<item><p><specref ref="vocabulary-namespaces"/></p></item>
+<item><p><specref ref="vocabulary-profiles"/></p></item>
+<item><p><specref ref="vocabulary-overview"/></p></item>
+</ulist>
+<div2 id="vocabulary-namespaces">
+<head>Namespaces</head>
+<p>The Timed Text Markup Language (TTML) employs a number of
+XML Namespaces <bibref ref="xmlns10"/> for elements and certain
+global attributes. The following table specifies this set of namespaces
+and indicates the default prefix used within this specification and the
+normative URI that denotes each namespace.</p>
+<note role="explanation">
+<p>In a specific <emph>Document Instance</emph>, it is not required that the default
+prefixes shown below are used. Any prefix or namespace binding that satisfies the constraints
+of XML Namespaces <bibref ref="xmlns10"/>  may be used that is associated with the specified namespace URI.</p>
+</note>
+<table id="namespace-vocab-table" role="common">
+<caption>Table 1 &ndash; Namespaces</caption>
+<col width="30%"/>
+<col/>
+<col/>
+<tbody>
+<tr>
+<th>Name</th>
+<th>Prefix</th>
+<th>Value</th>
+</tr>
+<tr>
+<td>TT</td>
+<td><code>tt:</code></td>
+<td><code>http://www.w3.org/ns/ttml</code></td>
+</tr>
+<tr>
+<td>TT Parameter</td>
+<td><code>ttp:</code></td>
+<td><code>http://www.w3.org/ns/ttml#parameter</code></td>
+</tr>
+<tr>
+<td>TT Style</td>
+<td><code>tts:</code></td>
+<td><code>http://www.w3.org/ns/ttml#styling</code></td>
+</tr>
+<tr>
+<td>TT Metadata</td>
+<td><code>ttm:</code></td>
+<td><code>http://www.w3.org/ns/ttml#metadata</code></td>
+</tr>
+<tr>
+<td>TT Profile</td>
+<td><emph>none</emph></td>
+<td><code>http://www.w3.org/ns/ttml/profile/</code></td>
+</tr>
+<tr>
+<td>TT Feature</td>
+<td><emph>none</emph></td>
+<td><code>http://www.w3.org/ns/ttml/feature/</code></td>
+</tr>
+<tr>
+<td>TT Extension</td>
+<td><emph>none</emph></td>
+<td><code>http://www.w3.org/ns/ttml/extension/</code></td>
+</tr>
+</tbody>
+</table>
+<note role="clarification">
+<p>If a reference to an element type is used in this specification and the name
+of the element type is not namespace qualified, then the TT Namespace applies.</p>
+<p>For certain namespaces defined above, the default prefix
+is specified as <emph>none</emph> if no XML vocabulary is defined in
+the namespace by this specification (nor expected to be defined in a
+future version of this specification). In such cases, the use of the
+namespace URI is for purposes other than defining XML vocabulary,
+e.g., for designating profiles, features, extensions and for
+dereferencing standard profile definitions.</p>
+</note>
+<p>All TTML Namespaces are <loc
+href="http://www.w3.org/2001/tag/doc/namespaceState#namespacedef"><emph>mutable</emph></loc>
+<bibref ref="nsstate"/>; all undefined names in these namespaces are reserved for future
+standardization by the W3C.</p>
+</div2>
+<div2 id="vocabulary-profiles">
+<head>Profiles</head>
+<p>The Timed Text Markup Language (TTML) employs a number of
+standard, predefined profiles of its
+vocabulary and associated semantics.
+The following table specifies this set of
+profiles, indicating
+a normative name
+and designator for each
+predefined profile,
+and where each of these profiles is formally elaborated in
+<specref ref="profiles"/> or in another TTWG specification.</p>
+<table id="profile-vocab-table" role="common">
+<caption>Table 2 &ndash; Profiles</caption>
+<col width="25%"/>
+<col/>
+<tbody>
+<tr>
+<th>Name</th>
+<th>Designator</th>
+</tr>
+<tr>
+<td>DFXP Transformation</td>
+<td><code>http://www.w3.org/ns/ttml/profile/dfxp-transformation</code></td>
+</tr>
+<tr>
+<td>DFXP Presentation</td>
+<td><code>http://www.w3.org/ns/ttml/profile/dfxp-presentation</code></td>
+</tr>
+<tr>
+<td>DFXP Full</td>
+<td><code>http://www.w3.org/ns/ttml/profile/dfxp-full</code></td>
+</tr>
+<tr>
+<td>SDP US</td>
+<td><code>http://www.w3.org/ns/ttml/profile/sdp-us</code></td>
+</tr>
+</tbody>
+</table>
+<p></p>
+<p>A profile designator must adhere to the
+<code>xsd:anyURI</code> data type defined by <bibref ref="xsd-2"/>,
+&sect;3.2.17. If the profile designator is expressed as a relative URI,
+then it must be absolutized by using the TT Profile Namespace value as
+the base URI.</p>
+<note role="example">
+<p>For example, if a profile designator is expressed as
+<code>dfxp-presentation</code>, then the absolutized profile designator
+would be
+<code>http://www.w3.org/ns/ttml/profile/dfxp-presentation</code>.</p>
+</note>
+<p>All profile designators which have the TT Profile Namespace as a prefix but are otherwise not listed in
+<specref ref="profile-vocab-table"/> are reserved for future standardization, and must not be appear in a conformant
+<emph>Document Instance</emph>. Nothwithstanding this constraint, a profile designator is not restricted to the set of designators enumerated
+in <specref ref="profile-vocab-table"/>, but may be any URI that feasibly dereferences a TTML <emph>Profile Definition Document</emph>
+provided it does not use the TT Profile Namespace as a prefix.</p>
+<p>The profile of TTML that must be supported by a
+TTML <emph>Content Processor</emph> in order to process a <emph>Document Instance</emph> is determined either (1) by specifying a
+<att>ttp:profile</att> attribute on the root <el>tt</el> element, as
+defined by <specref ref="parameter-attribute-profile"/>, or (2) by
+including one or more <el>ttp:profile</el>
+elements in the <el>head</el> element, in
+accordance with <specref ref="parameter-vocabulary-profile"/>.</p>
+<p>If a <el>ttp:profile</el> element appears as a
+descendant of the <el>tt</el> element, then the <loc
+href="#parameter-attribute-profile"><att>ttp:profile</att></loc>
+attribute should not be specified on the <el>tt</el> element. If both
+a <el>ttp:profile</el> element and a <att>ttp:profile</att>
+attribute are present (in a given <emph>Document Instance</emph>), then the
+<att>ttp:profile</att> attribute must be ignored for the purpose of
+determining the declared profile requirements.</p>
+<p>If more than one <el>ttp:profile</el> element appears in
+a <emph>Document Instance</emph>, then all specified profiles apply
+simultaneously.  In such a case, if some feature or some extension is
+specified by one profile to be used (mandatory and enabled) and by
+another profile to be required (mandatory) or optional (voluntary),
+then that feature or extension must be considered to be used
+(mandatory and enabled); if some feature or some extension is
+specified by one profile to be merely required (mandatory) and by
+another profile to be optional (voluntary), then that feature or
+extension must be considered to be required (mandatory).</p>
+<p>If neither
+<loc href="#parameter-attribute-profile"><att>ttp:profile</att></loc>
+attribute nor
+<loc href="#parameter-vocabulary-profile"><el>ttp:profile</el></loc>
+element is present in a <emph>Document Instance</emph>, and if the <emph>Document
+Interchange Context</emph> does not make an implicit or explicit
+reference to a pre-defined Content Profile or does not specify a <emph>Profile Definition
+Document</emph> or another equivalent set of feature designations,
+then the DFXP Transformation profile applies.</p>
+<note role="elaboration">
+<p>It is not a requirement on a conformant <emph>Document Instance</emph> that a <emph>Content Profile</emph> be internally
+defined by use of a <el>ttp:profile</el> element or internally referenced by a
+<att>ttp:profile</att> attribute. More specifically, it is permitted that the <emph>Document
+Interchange Context</emph> determines the applicable <emph>Content Profile</emph> through private
+agreement, out-of-band protocol, or common use (between sender and receiver) of a profile defined
+by an external specification.</p>
+</note>
+<note role="elaboration">
+<p>It is intended that the <att>ttp:profile</att> attribute be used when
+the author wishes to reference one of the standard, predefined profiles of
+TTML Content, and does not wish to modify (by supersetting or subsetting)
+that profile. This attribute may also be used by an author to indicate the use
+of a non-standard profile, in which case the specified profile designator expresses
+a URI that denotes an externally defined <emph>Profile Definition Document</emph>.
+However, it is not required that a conformant TTML Content Processor be able
+to dereference such an externally specified profile definition.</p>
+<p>In contrast, it is intended that the <el>ttp:profile</el> element be
+used when the author wishes to make use of a modified predefined profile or
+wishes to include in the <emph>Document Instance</emph> a non-standard profile definition
+not based upon one of the predefined profiles.</p>
+<p>A predefined profile is supersetted by specifying some feature or extension to
+be required (mandatory) that was either not specified in the underlying, baseline
+profile or was specified as optional (voluntary) in the baseline profile.
+A predefined profile is subsetted by specifying some feature or extension to
+be optional (voluntary) that was specified as required in the underlying, baseline
+profile.</p>
+<p>When a baseline profile is modified by subsetting, the resulting, derived profile
+is referred to as a <emph>subtractive</emph> profile; when modified by supersetting, the result
+is referred to as an <emph>additive</emph> profile.
+It is also possible to define a derived profile that is simultaneously subtractive
+and additive.</p>
+</note>
+<p>If a <emph>Document Instance</emph> makes use of a feature defined by
+<specref ref="feature-designations"/> and if the intended use of the
+document requires the recognition and processing of that feature, then
+the document must include a <emph>required feature</emph> or
+a <emph>used feature</emph>
+specification in one of its declared or
+referenced profiles.  If a <emph>Document Instance</emph> makes use
+of an extension designatable by <specref
+ref="extension-designations"/> and if the intended use of the document
+requires the recognition and processing of that extension, then the
+document must include a <emph>required extension</emph> or
+a <emph>used extension</emph> specification
+in one of its declared or referenced
+profiles.</p>
+<note role="elaboration">
+<p>A required or used feature
+specification is expressed directly (or indirectly by referring to a
+profile) by means of a <loc
+href="#parameter-vocabulary-feature"><el>ttp:feature</el></loc>
+element where the value of its <att>value</att> attribute is
+<code>required</code> or <code>use</code>,
+respectively.  A required or used
+extension specification is expressed directly (or indirectly by
+referring to a profile) by means of a <loc
+href="#parameter-vocabulary-extension"><el>ttp:extension</el></loc>
+element where the value of its <att>value</att> attribute is
+<code>required</code> or <code>use</code>,
+respectively.</p>
+</note>
+<p>An example of an author defined
+additive, derived profile of the DFXP Presentation
+profile is shown
+below in <specref ref="ttml-example-sub-profile"/>.</p>
+<table id="ttml-example-sub-profile" role="example">
+<caption>Example Fragment &ndash; DFXP Additive Profile</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;tt xml:lang="" xmlns="http://www.w3.org/ns/ttml"&gt;
+ &lt;head&gt;
+   &lt;profile use="dfxp-presentation" xmlns="http://www.w3.org/ns/ttml#parameter"&gt;
+     &lt;features xml:base="http://www.w3.org/ns/ttml/feature/"&gt;
+       &lt;feature value="required"&gt;#fontStyle-italic&lt;/feature&gt;
+     &lt;/features&gt;
+   &lt;/profile&gt;
+ &lt;/head&gt;
+ &lt;body/&gt;
+&lt;/tt&gt;
+</eg>
+</td></tr>
+</tbody>
+</table>
+<note role="explanation">
+<p>In the above example, the baseline profile is declared to be
+the DFXP Presentation profile, which is then additively modified by making the
+<code>#fontStyle-italic</code> feature required (rather than
+optional as it is defined
+in <specref ref="profile-dfxp-presentation"/>). Note also the resetting of the
+default XMLNS binding on the <el>profile</el> element to the TT Parameter Namespace.</p>
+</note>
+</div2>
+<div2 id="vocabulary-overview">
+<head>Catalog</head>
+<p>The vocabulary of the Timed Text Markup Language (TTML) is
+defined in the following major catalogs (divisions of vocabulary):</p>
+<ulist>
+<item><p><specref ref="core-vocabulary-overview"/></p></item>
+<item><p><specref ref="extension-vocabulary-overview"/></p></item>
+</ulist>
+<p>The core catalog defines the baseline, core vocabulary of TTML,
+and, in particular, the vocabulary of TTML Content. The extension catalog
+serves as a placeholder for extensions to the core vocabulary defined
+by TTML.</p>
+<div3 id="core-vocabulary-overview">
+<head>Core Catalog</head>
+<p>The core vocabulary catalog is intended to satisfy the needs of
+TTML while providing a baseline vocabulary for future profiles. This vocabulary
+is divided into distinct categories, specified in detail
+in the following sections:</p>
+<ulist>
+<item><p><specref ref="parameters"/></p></item>
+<item><p><specref ref="content"/></p></item>
+<item><p><specref ref="styling"/></p></item>
+<item><p><specref ref="layout"/></p></item>
+<item><p><specref ref="timing"/></p></item>
+<item><p><specref ref="animation"/></p></item>
+<item><p><specref ref="metadata"/></p></item>
+</ulist>
+<p>The core element vocabulary specified for use with a <emph>Document Instance</emph> is enumerated in
+<specref ref="element-vocab-table"/>.</p>
+<table id="element-vocab-table" role="common">
+<caption>Table 3 &ndash; Element Vocabulary</caption>
+<col width="25%"/>
+<col/>
+<tbody>
+<tr>
+<th>Module</th>
+<th>Elements</th>
+</tr>
+<tr>
+<td>
+Animation
+</td>
+<td>
+<loc href="#animation-vocabulary-set">set</loc>
+</td>
+</tr>
+<tr>
+<td>
+Content
+</td>
+<td>
+<loc href="#document-structure-vocabulary-body">body</loc>,
+<loc href="#content-vocabulary-div">div</loc>,
+<loc href="#content-vocabulary-p">p</loc>,
+<loc href="#content-vocabulary-span">span</loc>,
+<loc href="#content-vocabulary-br">br</loc>
+</td>
+</tr>
+<tr>
+<td>
+Document
+</td>
+<td>
+<loc href="#document-structure-vocabulary-tt">tt</loc>
+</td>
+</tr>
+<tr>
+<td>
+Head
+</td>
+<td>
+<loc href="#document-structure-vocabulary-head">head</loc>
+</td>
+</tr>
+<tr>
+<td>
+Layout
+</td>
+<td>
+<loc href="#layout-vocabulary-layout">layout</loc>,
+<loc href="#layout-vocabulary-region">region</loc>
+</td>
+</tr>
+<tr>
+<td>
+Metadata
+</td>
+<td>
+<loc href="#metadata-vocabulary-metadata">metadata</loc>
+</td>
+</tr>
+<tr>
+<td>
+Metadata Items
+</td>
+<td>
+<loc href="#metadata-vocabulary-actor">ttm:actor</loc>,
+<loc href="#metadata-vocabulary-agent">ttm:agent</loc>,
+<loc href="#metadata-vocabulary-copyright">ttm:copyright</loc>,
+<loc href="#metadata-vocabulary-desc">ttm:desc</loc>,
+<loc href="#metadata-vocabulary-name">ttm:name</loc>,
+<loc href="#metadata-vocabulary-title">ttm:title</loc>
+</td>
+</tr>
+<tr>
+<td>Parameter Items</td>
+<td><loc href="#parameter-vocabulary-profile">ttp:profile</loc>,
+<loc href="#parameter-vocabulary-features">ttp:features</loc>,
+<loc href="#parameter-vocabulary-feature">ttp:feature</loc>,
+<loc href="#parameter-vocabulary-extensions">ttp:extensions</loc>,
+<loc href="#parameter-vocabulary-extension">ttp:extension</loc>
+</td>
+</tr>
+<tr>
+<td>
+Styling
+</td>
+<td>
+<loc href="#styling-vocabulary-styling">styling</loc>,
+<loc href="#styling-vocabulary-style">style</loc>
+</td>
+</tr>
+</tbody>
+</table>
+<p></p>
+<p>Element vocabulary groups that are used in defining content models
+for TTML element types are enumerated in <specref ref="element-vocab-group-table"/>.</p>
+<table id="element-vocab-group-table" role="common">
+<caption>Table 4 &ndash; Element Vocabulary Groups</caption>
+<col width="25%"/>
+<col/>
+<tbody>
+<tr>
+<th>Group</th>
+<th>Elements</th>
+</tr>
+<tr>
+<td>
+Animation.class
+</td>
+<td>
+<loc href="#animation-vocabulary-set">set</loc>
+</td>
+</tr>
+<tr>
+<td>
+Block.class
+</td>
+<td>
+<loc href="#content-vocabulary-div">div</loc> |
+<loc href="#content-vocabulary-p">p</loc>
+</td>
+</tr>
+<tr>
+<td>
+Inline.class
+</td>
+<td>
+<loc href="#content-vocabulary-span">span</loc> |
+<loc href="#content-vocabulary-span">br</loc> |
+<code>#PCDATA</code>
+</td>
+</tr>
+<tr>
+<td>
+Metadata.class
+</td>
+<td>
+<loc href="#metadata-vocabulary-metadata">metadata</loc> |
+<loc href="#metadata-vocabulary-copyright">ttm:agent</loc> |
+<loc href="#metadata-vocabulary-copyright">ttm:copyright</loc> |
+<loc href="#metadata-vocabulary-desc">ttm:desc</loc> |
+<loc href="#metadata-vocabulary-title">ttm:title</loc>
+</td>
+</tr>
+<tr>
+<td>Parameters.class</td>
+<td><loc
+href="#parameter-vocabulary-profile">ttp:profile</loc></td>
+</tr>
+</tbody>
+</table>
+<p></p>
+<p>The attribute vocabulary specified for use with the core vocabulary
+catalog is enumerated in
+<specref ref="attribute-vocab-table"/>.</p>
+<table id="attribute-vocab-table" role="common">
+<caption>Table 5 &ndash; Attribute Vocabulary</caption>
+<col width="25%"/>
+<col/>
+<tbody>
+<tr>
+<th>Module</th>
+<th>Attributes</th>
+</tr>
+<tr>
+<td>
+Core Attributes
+</td>
+<td>
+<loc href="#content-attribute-id">xml:id</loc>,
+<loc href="#content-attribute-lang">xml:lang</loc>,
+<loc href="#content-attribute-space">xml:space</loc>
+</td>
+</tr>
+<tr>
+<td>
+Layout
+</td>
+<td>
+<loc href="#layout-attribute-region">region</loc>
+</td>
+</tr>
+<tr>
+<td>
+Metadata Attributes
+</td>
+<td>
+<loc href="#metadata-attribute-agent">ttm:agent</loc>,
+<loc href="#metadata-attribute-role">ttm:role</loc>
+</td>
+</tr>
+<tr>
+<td>
+Parameter Attributes
+</td>
+<td>
+<loc href="#parameter-attribute-cellResolution">ttp:cellResolution</loc>,
+<loc href="#parameter-attribute-clockMode">ttp:clockMode</loc>,
+<loc href="#parameter-attribute-dropMode">ttp:dropMode</loc>,
+<loc href="#parameter-attribute-frameRate">ttp:frameRate</loc>,
+<loc href="#parameter-attribute-frameRateMultiplier">ttp:frameRateMultipler</loc>,
+<loc href="#parameter-attribute-markerMode">ttp:markerMode</loc>,
+<loc href="#parameter-attribute-pixelAspectRatio">ttp:pixelAspectRatio</loc>,
+<loc href="#parameter-attribute-profile">ttp:profile</loc>,
+<loc href="#parameter-attribute-subFrameRate">ttp:subFrameRate</loc>,
+<loc href="#parameter-attribute-tickRate">ttp:tickRate</loc>,
+<loc href="#parameter-attribute-timeBase">ttp:timeBase</loc>
+</td>
+</tr>
+<tr>
+<td>
+Styling
+</td>
+<td>
+<loc href="#style-attribute-style">style</loc>
+</td>
+</tr>
+<tr>
+<td>
+Styling Attributes
+</td>
+<td>
+<loc href="#style-attribute-backgroundColor">tts:backgroundColor</loc>,
+<loc href="#style-attribute-color">tts:color</loc>,
+<loc href="#style-attribute-direction">tts:direction</loc>,
+<loc href="#style-attribute-display">tts:display</loc>,
+<loc href="#style-attribute-displayAlign">tts:displayAlign</loc>,
+<loc href="#style-attribute-extent">tts:extent</loc>,
+<loc href="#style-attribute-fontFamily">tts:fontFamily</loc>,
+<loc href="#style-attribute-fontSize">tts:fontSize</loc>,
+<loc href="#style-attribute-fontStyle">tts:fontStyle</loc>,
+<loc href="#style-attribute-fontWeight">tts:fontWeight</loc>,
+<loc href="#style-attribute-lineHeight">tts:lineHeight</loc>,
+<loc href="#style-attribute-opacity">tts:opacity</loc>,
+<loc href="#style-attribute-origin">tts:origin</loc>,
+<loc href="#style-attribute-overflow">tts:overflow</loc>,
+<loc href="#style-attribute-padding">tts:padding</loc>,
+<loc href="#style-attribute-showBackground">tts:showBackground</loc>,
+<loc href="#style-attribute-textAlign">tts:textAlign</loc>,
+<loc href="#style-attribute-textDecoration">tts:textDecoration</loc>,
+<loc href="#style-attribute-textOutline">tts:textOutline</loc>,
+<loc href="#style-attribute-unicodeBidi">tts:unicodeBidi</loc>,
+<loc href="#style-attribute-visibility">tts:visibility</loc>,
+<loc href="#style-attribute-wrapOption">tts:wrapOption</loc>,
+<loc href="#style-attribute-writingMode">tts:writingMode</loc>,
+<loc href="#style-attribute-zIndex">tts:zIndex</loc>
+</td>
+</tr>
+<tr>
+<td>
+Timing Attributes
+</td>
+<td>
+<loc href="#timing-attribute-begin">begin</loc>,
+<loc href="#timing-attribute-dur">dur</loc>,
+<loc href="#timing-attribute-end">end</loc>,
+<loc href="#timing-attribute-timeContainer">timeContainer</loc>
+</td>
+</tr>
+</tbody>
+</table>
+<note role="explanation">
+<p>Only those attributes defined as either (1) global, i.e., namespace qualified, or
+(2) shared element-specific, i.e., not namespace qualified but shared across multiple
+element types, are listed in <specref ref="attribute-vocab-table"/> above.
+</p>
+</note>
+<note role="explanation">
+<p>All vocabulary defined by TTML consistently makes use of
+the so-called <emph>lowerCamelCase</emph> naming convention. In some cases, this results in the
+change of a name when the name was based upon another specification
+that used a different naming convention.</p>
+</note>
+</div3>
+<div3 id="extension-vocabulary-overview">
+<head>Extension Catalog</head>
+<p>The extension vocabulary catalog is intended for use by future
+profiles of TTML, and is not further defined
+by this version of this specification.</p>
+<p>In addition to standardized extension vocabulary, a conforming 
+<emph>Document Instance</emph> may contain arbitrary namespace qualified
+elements that reside in any namespace other than those namespaces
+defined for use with this specification. Furthermore, a conforming 
+<emph>Document Instance</emph> may contain arbitrary namespace qualified
+attributes on TTML defined vocabulary where such attributes reside in
+any namespace other than those defined for use with this
+specification.</p>
+</div3>
+</div2>
+</div1>
+<div1 id="parameters">
+<head>Parameters</head>
+<p>This section specifies the <emph>parameters</emph> matter of the
+core vocabulary catalog, where
+parameters are to be understood as information that is either (1)
+essential or (2) of significant importance for the purpose of
+interpreting the semantics of other types of information expressed by
+core vocabulary items or for establishing a <emph>Document Processing Context</emph> by means
+of which TTML Content can be related to an external environment.</p>
+<div2 id="parameter-element-vocabulary">
+<head>Parameter Element Vocabulary</head>
+<p>The following elements, all defined in the TT Parameter
+Namespace, specify parametric information that applies to a <emph>Document Instance</emph>
+or <emph>Content Processor</emph>:</p>
+<ulist>
+<item><p><specref ref="parameter-vocabulary-profile"/></p></item>
+<item><p><specref ref="parameter-vocabulary-features"/></p></item>
+<item><p><specref ref="parameter-vocabulary-feature"/></p></item>
+<item><p><specref ref="parameter-vocabulary-extensions"/></p></item>
+<item><p><specref ref="parameter-vocabulary-extension"/></p></item>
+</ulist>
+<div3 id="parameter-vocabulary-profile">
+<head>ttp:profile</head>
+<p>The <el>ttp:profile</el> element is used to specify a collection of
+used (mandatory and enabled), required (mandatory),
+and optional (voluntary) features and extensions that must or
+may be supported by a <emph>Content Processor</emph> in order to process a
+<emph>Document Instance</emph> that makes (or may make) use of such features and
+extensions.</p>
+<note role="clarification">
+<p>The difference between a <emph>feature</emph> and an
+<emph>extension</emph> is where it is defined and how it is labeled:
+if defined in this specification (or a future revision thereof) and
+labeled with a feature designation in <specref ref="features"/>, then
+it is considered to be a feature; if defined in another specification
+and labeled there with an extension designation, then it is considered
+to be an extension. In general, features are expected to be defined by
+the W3C standards process, while extensions are expected to be defined by
+third parties.</p>
+</note>
+<p>This specification defines two distinct uses of the <el>ttp:profile</el> element:</p>
+<ulist>
+<item>
+<p>as a child of the <el>head</el> element within a TTML <emph>Document Instance</emph>;</p>
+</item>
+<item>
+<p>as the root element of a TTML <emph>Profile Definition Document</emph>
+instance;</p>
+</item>
+</ulist>
+<p>When a <el>tt:profile</el> element appears within a TTML <emph>Document Instance</emph>,
+its purpose is to express authorial intentions about which
+features and extensions must or may be supported by a recipient
+content processor. In addition, the element indirectly expresses
+information about the set of features or extensions that are (or may
+expected to be) used by the <emph>Document Instance</emph>.</p>
+<p>When a <el>tt:profile</el> element is used by a TTML <emph>Profile Definition Document</emph> instance,
+it serves to publish a machine
+readable specification of a specific TTML profile, of which
+this specification defines three such <emph>Profile Definition Documents</emph> in
+<specref ref="profiles"/>.</p>
+<p>The <el>ttp:profile</el> element accepts as its children zero or more
+elements in the <code>Metadata.class</code> element group, followed by
+zero or more <el>ttp:features</el> elements, followed by
+zero or more <el>ttp:extensions</el> elements.</p>
+<table id="elt-syntax-parameter-profile" role="syntax">
+<caption>XML Representation &ndash; Element Information Item: ttp:profile</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;ttp:profile
+  use = string
+  <loc href="#content-attribute-id">xml:id</loc> = ID
+  {<emph>any attribute not in default or any TT namespace</emph>}&gt;
+  <emph>Content:</emph> <loc href="#element-vocab-group-table">Metadata.class</loc>*, <loc href="#parameter-vocabulary-features">ttp:features</loc>*, <loc href="#parameter-vocabulary-extensions">ttp:extensions</loc>*
+&lt;/ttp:profile&gt;
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p>If specified, the <att>use</att> attribute must adhere to the
+<code>xsd:anyURI</code> data type defined by <bibref ref="xsd-2"/>,
+&sect;3.2.17, and, furthermore, must denote a profile designator in
+accordance with <specref ref="vocabulary-profiles"/>. In this case,
+the profile designator must refer to (1) a standard, predefined
+<emph>Profile Definition Document</emph> as defined by <specref ref="profiles"/>,
+or (2) a feasibly dereferenceable resource representing a valid <emph>Profile Definition
+Document</emph> instance. In either case, the referenced profile serves as the
+baseline profile of the specifying <el>ttp:profile</el> element.</p>
+<p>If the <att>use</att> attribute is not specified, then the baseline
+profile of the <el>ttp:profile</el> element must be considered to be
+the empty (null) profile, i.e., a profile definition containing no
+feature or extension specifications.</p>
+<p>The collection of features and extensions of a profile are determined according
+to the following ordered rules:</p>
+<olist>
+<item>
+<p>initialize the features and extensions of the profile to the empty
+set;</p>
+</item>
+<item>
+<p>if a <att>use</att> attribute is present, then augment the profile
+with the set of features and extensions specified by the referenced
+baseline profile;</p>
+</item>
+<item>
+<p>for each <el>ttp:feature</el> and <el>ttp:extension</el> element
+descendant of the <el>ttp:profile</el> element, using a post-order
+traversal, merge the specified feature or extension with the features
+and extensions of the profile, where merging a feature or extension
+entails replacing an existing feature or extension specification, if
+it already exists, or adding a new feature or extension specification,
+if it does not yet exist in the profile;</p>
+</item>
+</olist>
+<p>A conformant TTML processor is not required to be able to
+dereference a <emph>Profile Definition Document</emph> that is not one of the
+standard, predefined profiles defined by <specref ref="profiles"/>.  Furthermore,
+a conformant TTML processor may make use of a built-in, static
+form of each standard, predefined profile so as not to require
+dereferencing a network resource.</p>
+<p>If a TTML processor is unable to dereference a non-standard
+<emph>Profile Definition Document</emph>, then it must not further process the
+document without the presence of an explicit override from an end-user
+or some implementation specific parameter traceable to an end-user or
+to a user or system configuration setting. If a TTML processor aborts
+processing of a <emph>Document Instance</emph> due to the inability to
+reference a non-standard <emph>Profile Definition Document</emph>, then some
+end-user notification should be given unless the end-user or system
+has disabled such a notification, or if the processor does not permit
+or entail the intervention of an end-user.</p>
+<p>The <el>ttp:profile</el> element is illustrated by the following example.</p>
+<table id="parameter-vocabulary-profile-example-1" role="example">
+<caption>Example Fragment &ndash; ttp:profile</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;ttp:profile use="dfxp-presentation"&gt;
+  &lt;ttp:features xml:base="http://www.w3.org/ns/ttml/feature/"&gt;
+    &lt;ttp:feature&gt;#text-outline&lt;/ttp:feature&gt;
+  &lt;/ttp:features&gt;
+&lt;/ttp:profile&gt;
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<note role="explanation">
+<p>In the above example, the DFXP presentation profile is used as the
+baseline profile. This baseline profile is then supersetted (thus
+creating an additive derived profile) by requiring support for
+<code>#text-outline</code> feature.</p>
+</note>
+</div3>
+<div3 id="parameter-vocabulary-features">
+<head>ttp:features</head>
+<p>The <el>ttp:features</el> element is a container element used to group
+infomation about feature support requirements.</p>
+<p>The <el>ttp:features</el> element accepts as its children zero or more
+elements in the <code>Metadata.class</code> element group, followed by
+zero or more <el>ttp:feature</el> elements.</p>
+<table id="elt-syntax-parameter-features" role="syntax">
+<caption>XML Representation &ndash; Element Information Item: ttp:features</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;ttp:features
+  xml:base = string : <emph>TT Feature Namespace</emph>
+  <loc href="#content-attribute-id">xml:id</loc> = ID
+  {<emph>any attribute not in default or any TT namespace</emph>}&gt;
+  <emph>Content:</emph> <loc href="#element-vocab-group-table">Metadata.class</loc>*, <loc href="#parameter-vocabulary-feature">ttp:feature</loc>*
+&lt;/ttp:features&gt;
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p>If specified, the <att>xml:base</att>
+attribute must (1) adhere to the
+<code>xsd:anyURI</code> data type defined by <bibref ref="xsd-2"/>,
+&sect;3.2.17, (2) express an absolute URI that
+adheres to <bibref ref="xmlbase"/> and,
+(3) express a feature namespace as defined by
+<specref ref="feature-designations"/>. If not specified, the
+<att>xml:base</att> attribute's default
+value applies, which is the TT Feature Namespace.</p>
+<p>The <att>xml:base</att> attribute is
+used to permit the abbreviation of feature designation URIs expressed
+by child <el>ttp:feature</el> elements.</p>
+</div3>
+<div3 id="parameter-vocabulary-feature">
+<head>ttp:feature</head>
+<p>The <el>ttp:feature</el> element is used to specify
+infomation about support requirements for a particular feature.</p>
+<p>The children of the <el>ttp:feature</el> element must express a non-empty
+sequence of character information items that adheres to the
+<code>xsd:anyURI</code> data type defined by <bibref ref="xsd-2"/>,
+&sect;3.2.17.</p>
+<table id="elt-syntax-parameter-feature" role="syntax">
+<caption>XML Representation &ndash; Element Information Item: ttp:feature</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;ttp:feature
+  value = (optional|required|use) : required
+  <loc href="#content-attribute-id">xml:id</loc> = ID
+  {<emph>any attribute not in default or any TT namespace</emph>}&gt;
+  <emph>Content:</emph> #PCDATA
+&lt;/ttp:feature&gt;
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p>If the URI expressed by the content of the <el>ttp:feature</el>
+element is a relative URI, then, when combined with the
+feature namespace value expressed by the
+<att>xml:base</att> attribute of the
+nearest ancestor <el>ttp:features</el> element, it must express an
+absolute URI.  In either case (original absolute URI or resulting
+absolutized URI), the URI expressed by the <el>ttp:feature</el>
+element must further adhere to the syntax of a feature designation as
+defined by <specref ref="feature-designations"/>, and, furthermore,
+the specific designation that appears in this URI, i.e., the portion of the feature designation
+that starts with the fragment identifier separator '#', must
+be defined by this specification or some published version thereof (that
+has achieved REC status).</p>
+<p>If the URI expressed by the content of the <el>ttp:feature</el> element
+is a relative URI, then an <att>xml:base</att> attribute should be
+specified on the nearest ancestor <el>ttp:features</el> element.</p>
+<p>The <att>value</att> attribute specifies whether a conforming TTML
+processor must or may implement the designated feature in order to
+process the document. If the value of the <att>value</att> attribute
+is <code>optional</code>, then the processor need
+not implement or otherwise support the feature in order to process the
+document; if the value is <code>required</code>, then the processor
+must implement or otherwise support the feature, irrespective of
+whether the feature is enabled or disabled, in order to process
+the document; if the value is
+<code>use</code>, then the processor must both (1) implement or
+otherwise support the feature and (2) have enabled (activated) use of the
+feature.</p>
+<note role="clarification">
+<p>The default value of the <att>value</att> attribute is
+<code>required</code>, as indicated in the above element information
+item definition. Therefore, if a <att>value</att> attribute is not
+specified on a <el>ttp:feature</el> element, it is equivalent to
+specifying that support for the feature is required.</p>
+</note>
+<p>If the value of the <att>value</att> attribute is
+<code>required</code> or <code>use</code>
+and the TTML processor implementation does
+not support the feature, or if the <att>value</att> attribute is
+<code>use</code> and the TTML processor implementation supports but has disabled
+that feature, then it must not further process the document
+without the presence of an explicit override from an end-user or some
+implementation specific parameter traceable to an end-user or to a
+user or system configuration setting.  If a TTML processor aborts
+processing of a <emph>Document Instance</emph> due to the specification of a
+required, but unsupported feature by this element, then some end-user
+notification should be given unless the end-user or system has
+disabled such a notification, or if the processor does not permit or
+entail the intervention of an end-user.</p>
+<p>If the value of the <att>value</att> attribute is
+<code>optional</code>, and if the TTML processor implementation does
+not support the feature, then it may further process the document even
+in the case that some use of the feature is present in the document.
+In the case of actual use of a feature designated as optional, the
+default semantics associated with that feature apply; that is, the
+processor may behave as if the feature were not actually used or
+referenced by the document. Notwithstanding the above, the syntactic
+presence or reference to an optional feature by a document must not be
+considered to be a violation of document validity or a barrier to
+further processing if the syntactic expression is well-formed and
+valid.</p>
+<p>If some defined (i.e., standardized) or otherwise well known feature is not specified by
+a <el>ttp:feature</el> element in a given profile, then it must be interpreted as if the feature were specified
+with the <att>value</att> attribute equal to <code>optional</code>.</p>
+<note role="elaboration">
+<p>In particular, if some feature is not present in a profile definition, then
+it is not to be interpreted as meaning the use of that feature (in a <emph>Document Instance</emph>)
+is disallowed or otherwise prohibited.</p>
+</note>
+<p>The <el>ttp:feature</el> element is illustrated by the following example.</p>
+<table id="parameter-vocabulary-feature-example-1" role="example">
+<caption>Example Fragment &ndash; ttp:feature</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;ttp:profile use="http://www.w3.org/ns/ttml/profile/dfxp-presentation"&gt;
+  &lt;ttp:features xml:base="http://www.w3.org/ns/ttml/feature/"&gt;
+    <phrase role="strong">&lt;ttp:feature value="required"&gt;#fontStyle-italic&lt;/ttp:feature&gt;</phrase>
+    <phrase role="strong">&lt;ttp:feature value="required"&gt;#textDecoration-under&lt;/ttp:feature&gt;</phrase>
+  &lt;/ttp:features&gt;
+&lt;/ttp:profile&gt;
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<note role="explanation">
+<p>In the above example, the DFXP presentation profile is used as the
+baseline profile. This baseline profile is then modified by two
+<el>ttp:feature</el> elements in order to
+superset the baseline profile (since neither
+<code>#fontStyle-italic</code> nor <code>#textDecoration-under</code>
+are required by the DFXP presentation profile).</p> 
+<p>The effect of this example is to express authorial intentions that
+italic font style and text underlining must be
+supported.</p>
+</note>
+</div3>
+<div3 id="parameter-vocabulary-extensions">
+<head>ttp:extensions</head>
+<p>The <el>ttp:extensions</el> element is a container element used to group
+infomation about extension support requirements.</p>
+<p>The <el>ttp:extensions</el> element accepts as its children zero or more
+elements in the <code>Metadata.class</code> element group, followed by
+zero or more <el>ttp:extension</el> elements.</p>
+<table id="elt-syntax-parameter-extensions" role="syntax">
+<caption>XML Representation &ndash; Element Information Item: ttp:extensions</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;ttp:extensions
+  xml:base = string : <emph>TT Extension Namespace</emph>
+  <loc href="#content-attribute-id">xml:id</loc> = ID
+  {<emph>any attribute not in default or any TT namespace</emph>}&gt;
+  <emph>Content:</emph> <loc href="#element-vocab-group-table">Metadata.class</loc>*, <loc href="#parameter-vocabulary-extension">ttp:extension</loc>*
+&lt;/ttp:extensions&gt;
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p>If specified, the <att>xml:base</att>
+attribute must (1) adhere to the
+<code>xsd:anyURI</code> data type defined by <bibref ref="xsd-2"/>,
+&sect;3.2.17, (2) express an absolute URI that
+adheres to <bibref ref="xmlbase"/> and,
+(3) express an extension namespace as defined by
+<specref ref="extension-designations"/>. If not specified, the
+<att>xml:base</att> attribute's default
+value applies, which is the TT Extension Namespace.</p>
+<p>The <att>xml:base</att> attribute is
+used to permit the abbreviation of feature designation URIs expressed
+by child <el>ttp:extension</el> elements.</p>
+</div3>
+<div3 id="parameter-vocabulary-extension">
+<head>ttp:extension</head>
+<p>The <el>ttp:extension</el> element is used to specify
+infomation about support requirements for a particular extension.</p>
+<p>The children of the <el>ttp:extension</el> element must express a non-empty
+sequence of character information items that adheres to the
+<code>xsd:anyURI</code> data type defined by <bibref ref="xsd-2"/>,
+&sect;3.2.17.</p>
+<table id="elt-syntax-parameter-extension" role="syntax">
+<caption>XML Representation &ndash; Element Information Item: ttp:extension</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;ttp:extension
+  value = (optional|required|use) : required
+  <loc href="#content-attribute-id">xml:id</loc> = ID
+  {<emph>any attribute not in default or any TT namespace</emph>}&gt;
+  <emph>Content:</emph> #PCDATA
+&lt;/ttp:extension&gt;
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p>If the URI expressed by the content of the <el>ttp:extension</el>
+element is a relative URI, then, when combined with the
+extension namespace value expressed by the
+<att>xml:base</att> attribute of the
+nearest ancestor <el>ttp:extensions</el> element, it must express an
+absolute URI.  In either case (original absolute URI or resulting
+absolutized URI), the URI expressed by the <el>ttp:extension</el>
+element must further adhere to the syntax of an extension designation
+as defined by <specref ref="extension-designations"/>.</p>
+<p>If the URI expressed by the content of the
+<el>ttp:feature</el> element is a relative URI, then an
+<att>xml:base</att> attribute should be specified on the nearest
+ancestor <el>ttp:extensions</el> element.</p>
+<p>The <att>value</att> attribute specifies whether a conforming TTML
+processor must or may implement the designated extension in order to
+process the document. If the value of the <att>value</att> attribute
+is <code>optional</code>, then the processor need
+not implement or otherwise support the extension in order to process the
+document; if the value is <code>required</code>, then the processor
+must implement or otherwise support the extension in order to process
+the document; if the value is
+<code>use</code>, then the processor must both (1) implement or
+otherwise support the extension and (2) enable (activate) use of the
+extension.</p>
+<note role="clarification">
+<p>The default value of the <att>value</att> attribute is
+<code>required</code>, as indicated in the above element information
+item definition. Therefore, if a <att>value</att> attribute is not
+specified on a <el>ttp:extension</el> element, it is equivalent to
+specifying that support for the extension is required.</p>
+</note>
+
+<p>If the value of the <att>value</att> attribute is
+<code>required</code> or <code>use</code>
+and the TTML processor implementation does
+not support the extension, or if the <att>value</att> attribute is
+<code>use</code> and the TTML processor implementation supports but has disabled
+that extension, then it must not further process the document without the
+presence of an explicit override from an end-user or some
+implementation specific parameter traceable to an end-user or to a
+user or system configuration setting.  If a TTML processor aborts
+processing of a <emph>Document Instance</emph> due to the specification of a
+required, but unsupported extension by this element, then some
+end-user notification should be given unless the end-user or system
+has disabled such a notification, or if the processor does not permit
+or entail the intervention of an end-user.</p>
+<p>If the value of the <att>value</att> attribute is
+<code>optional</code>, and if the TTML processor implementation does
+not support the extension, then it may further process the document even
+in the case that some use of the extension is present in the document.
+In the case of actual use of an extension designated as optional, the
+default semantics associated with that extension apply; that is, the
+processor may behave as if the extension were not actually used or
+referenced by the document. Notwithstanding the above, the syntactic
+presence or reference to an optional extension by a document must not be
+considered to be a violation of document validity or a barrier to
+further processing if the syntactic expression is well-formed and
+valid.</p>
+<p>If some well known extension is not specified by
+a <el>ttp:extension</el> element in a given profile, then it must be interpreted as if the extension were specified
+with the <att>value</att> attribute equal to <code>optional</code>.</p>
+<note role="elaboration">
+<p>In particular, if some extension is not present in a profile definition, then
+it is not to be interpreted as meaning the use of that extension (in a <emph>Document Instance</emph>)
+is disallowed or otherwise prohibited.</p>
+</note>
+<p>The <el>ttp:extension</el> element is illustrated by the following example.</p>
+<table id="parameter-vocabulary-extension-example-1" role="example">
+<caption>Example Fragment &ndash; ttp:extension</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;ttp:profile use="http://www.w3.org/ns/ttml/profile/dfxp-transformation"&gt;
+  &lt;ttp:extensions xml:base="http://example.org/ttml/extension/"&gt;
+    <phrase role="strong">&lt;ttp:extension value="use"&gt;#prefilter-by-language&lt;/ttp:extension&gt;</phrase>
+  &lt;/ttp:extensions&gt;
+&lt;/ttp:profile&gt;
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<note role="explanation">
+<p>In the above example, the DFXP transformation profile is used as
+the baseline profile. This baseline profile is then supersetted by
+specifying that support and use is required for a private extension
+defined in a third party namespace.</p>
+<p>The effect of this example is to express authorial intentions that
+a recipient processor must support the DFXP transformation profile and
+must also support and enable an extension defined by a third party.</p>
+</note>
+</div3>
+</div2>
+<div2 id="parameter-attribute-vocabulary">
+<head>Parameter Attribute Vocabulary</head>
+<p>The following attributes are defined in the TT Parameter Namespace.</p>
+<ulist>
+<item><p><specref ref="parameter-attribute-cellResolution"/></p></item>
+<item><p><specref ref="parameter-attribute-clockMode"/></p></item>
+<item><p><specref ref="parameter-attribute-dropMode"/></p></item>
+<item><p><specref ref="parameter-attribute-frameRate"/></p></item>
+<item><p><specref ref="parameter-attribute-frameRateMultiplier"/></p></item>
+<item><p><specref ref="parameter-attribute-markerMode"/></p></item>
+<item><p><specref ref="parameter-attribute-pixelAspectRatio"/></p></item>
+<item><p><specref ref="parameter-attribute-profile"/></p></item>
+<item><p><specref ref="parameter-attribute-subFrameRate"/></p></item>
+<item><p><specref ref="parameter-attribute-tickRate"/></p></item>
+<item><p><specref ref="parameter-attribute-timeBase"/></p></item>
+</ulist>
+<p>Unless explicitly stated otherwise, linear white-space (LWSP) must
+appear between adjacent non-terminal components of a TT Parameter value
+unless some other delimiter is permitted and used.</p>
+<div3 id="parameter-attribute-cellResolution">
+<head>ttp:cellResolution</head>
+<p>The <att>ttp:cellResolution</att> attribute may be used by an author
+to express the number of horizontal and vertical cells into which the <emph>Root Container Region</emph>
+area is divided for the purpose of expressing presentation semantics in terms of
+a uniform grid.</p>
+<p>If specified, the value of this attribute must adhere to the following syntax:</p>
+<table id="parameter-attribute-cellResolution-syntax" role="syntax">
+<caption>Syntax Representation &ndash; ttp:cellResolution</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+ttp:cellResolution
+  : columns rows                            // <emph>columns</emph> != 0; <emph>rows</emph> != 0
+
+columns | rows
+  : <loc href="#style-value-digit">&lt;digit&gt;</loc>+
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p>If not specified, the number of columns and rows must be considered
+to be 32 and 15, respectively. If specified, then columns or rows must not be zero (0).</p>
+<note role="motivation">
+<p>The choice of values 32 and 15 are based on this being the
+maximum number of columns and rows defined by <bibref
+ref="cea608c"/>.</p>
+</note>
+<p>A <att>ttp:cellResolution</att> attribute is considered to be significant only
+when specified on the <el>tt</el> element.</p>
+<note role="explanation">
+<p>The use of a uniform grid is employed only for the purpose of
+measuring lengths and expressing coordinates. In particular, it is not
+assumed that the presentation of text or the alignment of individual
+glyph areas is
+coordinated with this grid. Such alignment is possible, but
+requires the use of a monospaced font and a font size whose EM square exactly
+matches the cell size.</p>
+</note>
+<p>Except where indicated otherwise, when a <loc href="#style-value-length">&lt;length&gt;</loc> expressed in
+cells denotes a dimension parallel to the inline or block progression dimension,
+the cell's dimension in the inline or block progression dimension applies, respectively.</p>
+<note role="example">
+<p>For example, if padding (on all four edges) is specified as 0.1c, the cell resolution
+is 20 by 10, and the extent of the <emph>Root Container Region</emph> is 640 by 480, then, assuming top to bottom,
+left to right writing mode, the start and end padding will be (640 / 20) * 0.1 pixels and the
+before and after padding will be (480 / 10) * 0.1 pixels.</p>
+</note>
+</div3>
+<div3 id="parameter-attribute-clockMode">
+<head>ttp:clockMode</head>
+<p>The <att>ttp:clockMode</att> attribute is used to specify the
+interpretation of time expressions as real-time time coordinates when
+operating with time base of <code>clock</code> as defined by <specref
+ref="parameter-attribute-timeBase"/>.</p>
+<note role="explanation">
+<p>See <specref ref="timing-time-value-expressions"/> for the
+specification of time expression syntax and semantics.</p>
+</note>
+<p>If specified, the value of this attribute must adhere to the following syntax:</p>
+<table id="parameter-attribute-clockMode-syntax" role="syntax">
+<caption>Syntax Representation &ndash; ttp:clockMode</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+ttp:clockMode
+  : "local"
+  | "gps"
+  | "utc"
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p>If the time base, defined by <specref
+ref="parameter-attribute-timeBase"/>, is designated as
+<code>clock</code>, then this parameter applies as follows: if the
+parameter's value is <code>local</code>, then time expressions are
+interpreted as local wall-clock time coordinates;
+if <code>utc</code>, then time expressions are
+interpreted as UTC time coordinates
+<bibref ref="utc"/>;
+if <code>gps</code>, then time expressions are
+interpreted as GPS time coordinates
+<bibref ref="gps"/>.</p>
+<note role="explanation">
+<p>The primary difference between GPS time and UTC time is that GPS
+time is not adjusted for leap seconds, while UTC time is adjusted as
+follows: UTC = TAI (<emph>Temp Atomique International</emph>) + <emph>leap seconds
+accumulated since 1972</emph>. TAI is maintained by the <emph>Bureau
+International des Poids et Mesures</emph> (BIPM) in Sevres, France.
+The GPS system time is steered to a Master Clock (MC) at the US Naval
+Observatory which is kept within a close but unspecified
+tolerance of TAI.</p>
+</note>
+<p>If not specified, the value of this parameter must be considered
+to be <code>utc</code>.</p>
+<p>A <att>ttp:clockMode</att> attribute is considered to be significant only
+when specified on the <el>tt</el> element.</p>
+</div3>
+<div3 id="parameter-attribute-dropMode">
+<head>ttp:dropMode</head>
+<p>The <att>ttp:dropMode</att> attribute is used to specify
+constraints on the interpretation and use of frame counts
+that correspond with <bibref ref="smpte12m"/> time coordinates when operating
+with time base of <code>smpte</code> as defined by
+<specref ref="parameter-attribute-timeBase"/>.</p>
+<p>If specified, the value of this attribute must adhere to the following syntax:</p>
+<table id="parameter-attribute-dropMode-syntax" role="syntax">
+<caption>Syntax Representation &ndash; ttp:dropMode</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+ttp:dropMode
+  : "dropNTSC"
+  | "dropPAL"
+  | "nonDrop"
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p>If the time base, defined by <specref
+ref="parameter-attribute-timeBase"/>, is designated as
+<code>smpte</code>, then this parameter applies as follows: if the
+parameter's value is <code>nonDrop</code>, then, within any given
+second of a time expression, frames count from 0 to
+<emph>N&minus;1</emph>, where <emph>N</emph> is the value specified by
+the <att>ttp:frameRate</att> parameter, but while ignoring any value
+specified by the <att>ttp:frameRateMultiplier</att> parameter.</p>
+<note role="clarification"> <p>When operating in <code>nonDrop</code>
+mode, a second of a time expression may or may not be equal to a
+second of real time during normal (1x speed) forward playback. If the
+<att>ttp:frameRateMultiplier</att> parameter is specified and is not
+equal to 1:1, then a second of a time expression will either be
+shorter or longer than a second of elapsed play in real
+time.</p></note>
+<p>If this parameter's value is <code>dropNTSC</code>, then, within any
+given second of a time expression except the second <code>00</code>,
+frames count from 0 to <emph>N&minus;1</emph>, where <emph>N</emph> is
+the value specified by the <att>ttp:frameRate</att> parameter, but
+while ignoring any value specified by the
+<att>ttp:frameRateMultiplier</att> parameter. If the second of a time
+expression is <code>00</code> and the minute of the time expression is
+not <code>00</code>, <code>10</code>, <code>20</code>, <code>30</code>,
+<code>40</code>, or <code>50</code>, then frame codes <code>00</code>
+and <code>01</code> are dropped during that second; otherwise, these
+frame codes are not dropped.</p>
+<note role="example"> <p>For example, when operating in <code>dropNTSC</code>
+mode with <att>ttp:frameRate</att> of <code>30</code>, a discontinuity
+in frame count occurs between consecutive frames as shown in the
+following sequence of time expressions: <code>01:08:59:28</code>,
+<code>01:08:59:29</code>, <code>01:09:00:02</code>,
+<code>01:09:00:03</code>.</p></note>
+<p>If this parameter's value is <code>dropPAL</code>, then, within any
+given second of a time expression except the second <code>00</code>,
+frames count from 0 to <emph>N&minus;1</emph>, where <emph>N</emph> is
+the value specified by the <att>ttp:frameRate</att> parameter, but
+while ignoring any value specified by the
+<att>ttp:frameRateMultiplier</att> parameter. If the second of a time
+expression is <code>00</code> and the minute of the time expression is
+even but not <code>00</code>, <code>20</code>, or <code>40</code>,
+then frame codes <code>00</code> through <code>03</code> are dropped
+during that second; otherwise, these frame codes are not dropped.</p>
+<note role="example"><p>For example, when operating in <code>dropPAL</code>
+mode with <att>ttp:frameRate</att> of <code>30</code>, a discontinuity
+in frame count occurs between consecutive frames as shown in the
+following sequence of time expressions: <code>01:09:59:28</code>,
+<code>01:09:59:29</code>, <code>01:10:00:04</code>,
+<code>01:10:00:05</code>.</p></note>
+<note role="explanation">
+<p>The <code>dropPAL</code> mode is also known as the
+<emph>M/PAL</emph> or <emph>PAL (M)</emph> drop-frame
+code, which uses PAL modulation with the NTSC frame rate of ~29.97
+frames/second. The M/PAL system is used primarily in Brazil.</p>
+</note>
+<p>If not specified, then <code>nonDrop</code> must be assumed to apply.</p>
+<p>A <att>ttp:dropMode</att> attribute is considered to be significant only
+when specified on the <el>tt</el> element.</p>
+</div3>
+<div3 id="parameter-attribute-frameRate">
+<head>ttp:frameRate</head>
+<p>The <att>ttp:frameRate</att> attribute is used to specify the frame rate of a related
+media object or the intrinsic frame rate of a <emph>Document Instance</emph> in case it is intended
+to function as an independent media object.</p>
+<p>If specified, the value of this attribute must adhere to the following syntax:</p>
+<table id="parameter-attribute-frameRate-syntax" role="syntax">
+<caption>Syntax Representation &ndash; ttp:frameRate</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+ttp:frameRate
+  : <loc href="#style-value-digit">&lt;digit&gt;</loc>+                                // <emph>value</emph> > 0
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p>The frame rate that applies to a <emph>Document Instance</emph> is used to
+interpret time expressions that are expressed in <emph>frames</emph>
+as defined by <specref ref="timing-value-timeExpression"/>.</p>
+<p>If the <code>media</code> time base applies and the effective frame rate is
+integral, then a frame is interpreted as a division of a second of media
+time, such that if the frame rate is specified as <emph>F</emph>, then
+a second of media time is divided into <emph>F</emph> intervals of
+equal duration, where each interval is labeled as frame <emph>f</emph>,
+with <emph>f</emph> &isin; [0&hellip;<emph>F&minus;1</emph>].</p>
+<note role="elaboration">
+<p>See <specref ref="time-expression-semantics-media"/> for further details
+on the interpretation of time expressions for the <code>media</code> time base.</p>
+</note>
+<p>If not specified, the frame rate must be considered to be equal to some
+application defined frame rate, or if no application defined frame rate applies,
+then thirty (30) frames per second. If specified, then the frame rate must
+be greater than zero (0).</p>
+<p>A <att>ttp:frameRate</att> attribute is considered to be significant only
+when specified on the <el>tt</el> element.</p>
+</div3>
+<div3 id="parameter-attribute-frameRateMultiplier">
+<head>ttp:frameRateMultiplier</head>
+<p>The <att>ttp:frameRateMultiplier</att> attribute is used to
+specify a multiplier to be applied to the frame rate specified by a
+<att>ttp:frameRate</att> attribute in order to compute the effective
+frame rate.</p>
+<p>If specified, the value of this attribute must adhere to the following syntax:</p>
+<table id="parameter-attribute-frameRateMultiplier-syntax" role="syntax">
+<caption>Syntax Representation &ndash; ttp:frameRateMultiplier</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+ttp:frameRateMultiplier
+  : numerator denominator                   // <emph>numerator</emph> != 0; <emph>denominator</emph> != 0
+
+numerator | denominator
+  : <loc href="#style-value-digit">&lt;digit&gt;</loc>+
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p>A frame rate multiplier is used when the desired frame rate cannot
+be expressed as an integral number of frames per second.</p>
+<p>If not specified, the frame rate multiplier must be considered to be equal to one (1:1).
+Both numerator and denominator must be non-zero.</p>
+<p>A <att>ttp:frameRateMultiplier</att> attribute is considered to be significant only
+when specified on the <el>tt</el> element.</p>
+<note role="example">
+<p>The frame rate multiplier used for synchronizing with NTSC <bibref
+ref="smpte170m"/>
+formatted video objects at 30 frames per second is nominally
+1000:1001. The nominal frame rate of NTSC video is defined as the chrominance
+sub-carrier frequency of 3,579,545.45&hellip;Hz (= 5.0MHz &mult; 63/88) times the ratio 2/455 divided by
+the number of horizontal lines per frame of 525, which yields a frame
+rate of 29.970029970029&hellip; (= 30 &mult; 1000/1001) frames per
+second. Other frame rate multipliers apply to different regions of
+usage and video format standards.</p>
+</note>
+<note role="example">
+<p>Except in the case of PAL/M, the frame rate multiplier used for synchronizing with PAL
+formatted video objects at 25 frames per second is nominally 1:1.</p>
+</note>
+</div3>
+<div3 id="parameter-attribute-markerMode">
+<head>ttp:markerMode</head>
+<p>The <att>ttp:markerMode</att> attribute is used to specify
+constraints on the interpretation and use of time expressions
+that correspond with <bibref ref="smpte12m"/> time coordinates when operating
+with time base of <code>smpte</code> as defined by
+<specref ref="parameter-attribute-timeBase"/>.</p>
+<p>If specified, the value of this attribute must adhere to the following syntax:</p>
+<table id="parameter-attribute-markerMode-syntax" role="syntax">
+<caption>Syntax Representation &ndash; ttp:markerMode</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+ttp:markerMode
+  : "continuous"
+  | "discontinuous"
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p>If the time base, defined by <specref
+ref="parameter-attribute-timeBase"/>, is designated as
+<code>smpte</code>, then this parameter applies as follows: if the
+parameter's value is <code>continuous</code>, then <bibref ref="smpte12m"/> time coordinates
+may be assumed to be linear and either monotonically increasing or
+decreasing; however, if <code>discontinuous</code>, then any assumption
+must not be made regarding linearity or monotonicity of time coordinates.</p>
+<p>If not specified, the value of this parameter must be considered
+to be <code>discontinuous</code>.</p>
+<note role="historical">
+<p>The default value for this parameter was originally specified
+(in <xspecref href="http://www.w3.org/TR/2010/REC-ttaf1-dfxp-20101118/">TTML 1.0 First Edition</xspecref>)
+as <code>continuous</code>; however, further evaluation of the state of the industry indicates this
+choice was incorrect, and that the most common default is <code>discontinuous</code>.</p>
+</note>
+<note role="recommendation">
+<p>Due to lack of industry consensus on the utility and interpretation of the
+<code>continuous</code> marker mode, authors are advised to avoid its use. Furthermore, the
+<att>ttp:markerMode</att> is being considered for deprecation in the next revision of this
+specification.</p>
+</note>
+<p>A <att>ttp:markerMode</att> attribute is considered to be significant only
+when specified on the <el>tt</el> element.</p>
+<p>If a value of <code>continuous</code> applies, then time
+expressions may be converted to real time
+coordinates by taking into account the computed frame rate
+and drop mode as expressed by the <att>ttp:dropMode</att> parameter.
+In this case, the <emph>Content Processor</emph> must create and maintain a
+<emph>Synthetic SMPTE Document Syncbase</emph> within which these time
+expressions are interpreted as further described in
+<specref ref="timing-time-intervals"/>.</p>
+<note role="explanation">
+<p>When operating with <code>smpte</code> time base and
+<code>continuous</code> marker mode, there is an implied time coordinate
+space, the <emph>Synthetic SMPTE Document Syncbase</emph>,
+defined by the monotonically increasing (or decreasing) 
+<bibref ref="smpte12m"/> time coordinates, while taking into account
+the computed frame rate and drop mode. All time expressions are interpreted
+in relationship to this time coordinate space based upon
+<emph>SMPTE Time Code</emph> synchronization events (markers),
+where the <emph>Document Processing Context</emph>  emits these events with implied constraints
+regarding time coordinate monoticity and resynchronization in
+the presence of dropped frames.</p>
+<p>Use of <code>continuous</code> marker mode with the <code>smpte</code>
+time base is different from using the <code>media</code> time base
+because (1) the semantics of the <att>ttp:dropMode</att> parameter
+apply to the former, but not the latter, and (2) <bibref ref="smpte12m"/>
+time coordinates may be applied monotonically to media which has been
+subjected to dilation in time, constriction in time, or reversal in
+time.</p>
+</note>
+<p>If a value of <code>discontinuous</code> applies, then time
+expressions must not be converted to real time
+coordinates, arithmetical operators (addition, multiplication) are not
+defined on time expressions, and, consequently, any (well-formed)
+expression of a duration must be considered to be invalid.</p>
+<note role="explanation">
+<p>When operating with <code>smpte</code> time base and
+<code>discontinuous</code> marker mode, there is no effective time coordinate
+space; rather, all time expressions are interpreted as labeled
+synchronization events (markers), where the <emph>Document Processing Context</emph>
+emits these events, which, when they correspond with time
+expressions that denote the same label, cause a temporal interval to
+begin or end accordingly.</p>
+<p>An additional side-effect of operating in <code>discontinuous</code>
+mode is that time expressions of children have no necessary
+relationship with time expressions of their temporal container; that
+is, temporal containers and children of these containers are
+temporally activated and inactivated independently based on the
+occurrence of a labeled synchronization (marker) event.</p>
+</note>
+<note role="explanation">
+<p>The notion of marker discontinuity as captured by this parameter
+is logically independent from the method used to count frames as
+expressed by the <att>ttp:dropMode</att> parameter. In particular,
+even if the <att>ttp:dropMode</att> parameter is specified as
+<code>dropNTSC</code> or <code>dropPAL</code>, the marker mode may be
+specified as <code>continuous</code>, even in the presence of frame count
+discontinuities induced by the frame counting method, unless there
+were some other non-linearity or discontinuity in marker labeling, for
+example, two consecutive frames labeled as <code>10:00:00:00</code>
+and <code>10:00:01:00</code>.
+</p>
+</note>
+</div3>
+<div3 id="parameter-attribute-pixelAspectRatio">
+<head>ttp:pixelAspectRatio</head>
+<p>The <att>ttp:pixelAspectRatio</att> attribute may be used by a content author
+to express the aspect ratio of non-square pixels in the production of content that
+makes use of pixel coordinates.</p>
+<p>If specified, the value of this attribute must adhere to the following syntax:</p>
+<table id="parameter-attribute-pixelAspectRatio-syntax" role="syntax">
+<caption>Syntax Representation &ndash; ttp:pixelAspectRatio</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+ttp:pixelAspectRatio
+  : width height                            // <emph>width</emph> != 0; <emph>height</emph> != 0
+
+width | height
+  : <loc href="#style-value-digit">&lt;digit&gt;</loc>+
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p>If not specified, then square pixels (i.e., aspect ratio 1:1) must be assumed to apply.
+If specified, then both width and height must be non-zero.</p>
+<p>A <att>ttp:pixelAspectRatio</att> attribute is considered to be significant only
+when specified on the <el>tt</el> element.</p>
+<note role="explanation">
+<p>This parameter may be used by a content transcoder or translator in
+order to convert pixel measurements between different pixel aspect
+ratios while still maintaining authorial layout intentions.</p>
+</note>
+</div3>
+<div3 id="parameter-attribute-profile">
+<head>ttp:profile</head>
+<p>The <att>ttp:profile</att> attribute may be used by a content author
+to express the profile of the Timed Text Markup Language (TTML) used
+in a <emph>Document Instance</emph>.</p>
+<p>If specified, the value of this attribute must adhere to the
+<code>xsd:anyURI</code> data type defined by <bibref ref="xsd-2"/>,
+&sect;3.2.17, and, further, must specify a
+profile designator in accordance with
+<specref ref="vocabulary-profiles"/>.</p>
+<p>A <att>ttp:profile</att>
+attribute is considered to be significant only when specified on the
+<el>tt</el> element.</p>
+</div3>
+<div3 id="parameter-attribute-subFrameRate">
+<head>ttp:subFrameRate</head>
+<p>The <att>ttp:subFrameRate</att> attribute is used to specify the sub-frame rate of a related
+media object or the intrinsic sub-frame rate of a <emph>Document Instance</emph> in case it is intended
+to function as an independent media object.</p>
+<p>If specified, the value of this attribute must adhere to the following syntax:</p>
+<table id="parameter-attribute-subFrameRate-syntax" role="syntax">
+<caption>Syntax Representation &ndash; ttp:subFrameRate</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+ttp:subFrameRate
+  : <loc href="#style-value-digit">&lt;digit&gt;</loc>+                                // <emph>value</emph> > 0
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p>The sub-frame rate that applies to a <emph>Document Instance</emph> is used to
+interpret time expressions that are expressed in <emph>sub-frames</emph>
+as defined by <specref ref="timing-value-timeExpression"/>.</p>
+<p>If the <code>media</code> time base applies and the effective frame rate is
+integral, a sub-frame is interpreted as a division of a frame of media
+time, such that if the sub-frame rate is specified as <emph>S</emph>, then
+a frame of media time is divided into <emph>S</emph> intervals of
+equal duration, where each interval is labeled as sub-frame <emph>s</emph>,
+with <emph>s</emph> &isin; [0&hellip;<emph>S&minus;1</emph>].</p>
+<note role="elaboration">
+<p>See <specref ref="time-expression-semantics-media"/> for further details
+on the interpretation of time expressions for the <code>media</code> time base.</p>
+</note>
+<p>If not specified, the sub-frame rate must be considered to be
+equal to one (1). If specified, then the sub-frame rate must be greater than zero (0).</p>
+<p>A <att>ttp:subFrameRate</att> attribute is considered to be significant only
+when specified on the <el>tt</el> element.</p>
+<note role="clarification">
+<p>The sub-frame is sometimes referred to as a <emph>field</emph> in
+the context of synchronization with an interlaced video media object.</p>
+</note>
+</div3>
+<div3 id="parameter-attribute-tickRate">
+<head>ttp:tickRate</head>
+<p>The <att>ttp:tickRate</att> attribute is used to specify the tick rate of a related
+media object or the intrinsic tick rate of content of a <emph>Document Instance</emph> in case it is intended
+to function as an independent media object.</p>
+<p>If specified, the value of this attribute must adhere to the following syntax:</p>
+<table id="parameter-attribute-tickRate-syntax" role="syntax">
+<caption>Syntax Representation &ndash; ttp:tickRate</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+ttp:tickRate
+  : <loc href="#style-value-digit">&lt;digit&gt;</loc>+                                // <emph>value</emph> > 0
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p>The tick rate that applies to a <emph>Document Instance</emph> is used to
+interpret time expressions that are expressed in <emph>ticks</emph> by
+using the <code>t</code> metric as defined by <specref
+ref="timing-value-timeExpression"/>.</p>
+<p>If the <code>media</code> time base applies,
+a tick is interpreted as an integral division of a second of media
+time, such that if the tick rate is specified as <emph>T</emph>, then
+a second of media time is divided into <emph>T</emph> intervals of
+equal duration, where each interval is labeled as tick <emph>t</emph>,
+with <emph>t</emph> &isin; [0&hellip;<emph>T&minus;1</emph>].</p>
+<note role="elaboration">
+<p>See <specref ref="time-expression-semantics-media"/> for further details
+on the interpretation of time expressions for the <code>media</code> time base.</p>
+</note>
+<p>If not specified, then if a frame rate is specified, the tick rate
+must be considered to be the effective frame rate multiplied by the
+sub-frame rate (i.e., ticks are interpreted as sub-frames); or, if no
+frame rate is specified, the tick rate must be considered to be one (1)
+tick per second of media time. If specified, then the tick rate
+must not be zero (0).</p>
+<note role="clarification">
+<p>There is no predefined relationship between ticks and frames or
+sub-frames. Ticks are an arbitrary division of seconds that permit
+use of fixed point arithmetic rather than fractional (and potentially
+inexact) expressions of seconds.</p>
+</note>
+<p>A <att>ttp:tickRate</att> attribute is considered to be significant only
+when specified on the <el>tt</el> element.</p>
+</div3>
+<div3 id="parameter-attribute-timeBase">
+<head>ttp:timeBase</head>
+<p>The <att>ttp:timeBase</att> attribute is used to specify the
+temporal coordinate system by means of which time expressions are
+interpreted in a <emph>Document Instance</emph>.</p>
+<p>If specified, the value of this attribute must adhere to the following syntax:</p>
+<table id="parameter-attribute-timeBase-syntax" role="syntax">
+<caption>Syntax Representation &ndash; ttp:timeBase</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+ttp:timeBase
+  : "media"
+  | "smpte"
+  | "clock"
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p>If the time base is designated as <code>media</code>, then a time
+expression denotes a coordinate in some media object's time line,
+where the media object may be an external media object with which the
+content of a <emph>Document Instance</emph> is to be synchronized, or it may
+be the content of a <emph>Document Instance</emph> itself in a case where
+the timed text content is intended to establish an independent time
+line.</p>
+<note role="explanation">
+<p>When using a media time base, if that time base is paused or
+scaled positively or negatively, i.e., the media play rate is
+not unity, then it is expected that the
+presentation of associated Timed Text content will be similarly
+paused, accelerated, or decelerated, respectively. The means for
+controlling an external
+media time base is outside the scope of this specification.</p>
+</note>
+<p>If the time base is designated as <code>smpte</code>,
+then a time expression denotes a <bibref ref="smpte12m"/> time
+coordinate with which the content of a <emph>Document Instance</emph> is to
+be synchronized.  In this case, the value of the <att>ttp:markerMode</att> 
+and <att>ttp:dropMode</att> parameters apply, as defined by <specref
+ref="parameter-attribute-markerMode"/> and <specref
+ref="parameter-attribute-dropMode"/>, respectively.</p>
+<note role="explanation">
+<p>When the time base is designated as <code>smpte</code>,
+every time expression denotes a media marker value akin to that
+defined by <bibref ref="smil21"/>, &sect; 10.4.1, except instead
+of using an opaque marker name, a structured <bibref ref="smpte12m"/>
+time coordinate serves as the marker name.</p>
+</note>
+<p>If the time base is designated as <code>clock</code>, then the time
+expression denotes a coordinate in some real-world time line as
+established by some real-time clock, such as the local wall-clock time
+or UTC (Coordinated Universal Time) or GPS (Global Positioning System)
+time lines.</p>
+<p>If not specified, the default time base must be considered to be
+<code>media</code>.</p>
+<p>A <att>ttp:timeBase</att> attribute is considered to be significant only
+when specified on the <el>tt</el> element.</p>
+<p>When operating with either <code>media</code> or <code>smpte</code>
+time bases, a diachronic presentation of a <emph>Document Instance</emph> may
+be subject to transformations of the controlling time line, such as
+temporal reversal, dilation (expansion), or constriction
+(compression); however, when operating with the <code>clock</code>
+time base, no transformations are permitted, and diachronic
+presentation proceeds on a linear, monotonically increasing time line
+based on the passage of real time.</p>
+<note role="example">
+<p>Due to there being only one time base parameter that applies to a
+given <emph>Document Instance</emph>, the interpretation of time expressions
+is uniform throughout the <emph>Document Instance</emph>.</p>
+</note>
+<note role="elaboration">
+<p>See <specref ref="time-expression-semantics"/> for further details
+on the interpretation of time expressions according to the designated time base.</p>
+</note>
+</div3>
+</div2>
+</div1>
+<div1 id="content">
+<head>Content</head>
+<p>This section specifies the <emph>content</emph> matter of the core
+vocabulary catalog.</p>
+<div2 id="content-element-vocabulary">
+<head>Content Element Vocabulary</head>
+<p>The following elements specify the structure and principal content aspects of a
+<emph>Document Instance</emph>:</p>
+<ulist>
+<item><p><specref ref="document-structure-vocabulary-tt"/></p></item>
+<item><p><specref ref="document-structure-vocabulary-head"/></p></item>
+<item><p><specref ref="document-structure-vocabulary-body"/></p></item>
+<item><p><specref ref="content-vocabulary-div"/></p></item>
+<item><p><specref ref="content-vocabulary-p"/></p></item>
+<item><p><specref ref="content-vocabulary-span"/></p></item>
+<item><p><specref ref="content-vocabulary-br"/></p></item>
+</ulist>
+<div3 id="document-structure-vocabulary-tt">
+<head>tt</head>
+<p>The <el>tt</el> element serves as the root document element of a <emph>Document Instance</emph>.</p>
+<p>The <el>tt</el> element accepts as its children zero or one <el>head</el> element followed by
+zero or one <el>body</el> element.</p>
+<table id="elt-syntax-tt" role="syntax">
+<caption>XML Representation &ndash; Element Information Item: tt</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;tt
+  <loc href="#style-attribute-extent">tts:extent</loc> = string
+  <loc href="#content-attribute-id">xml:id</loc> = ID
+  <loc href="#content-attribute-lang"><phrase role="reqattr">xml:lang</phrase></loc> = string
+  <loc href="#content-attribute-space">xml:space</loc> = (<emph>default</emph>|<emph>preserve</emph>) : default
+  {<emph>any attribute in TT Parameter namespace</emph>}
+  {<emph>any attribute not in default or any TT namespace</emph>}&gt;
+  <emph>Content:</emph> <loc href="#document-structure-vocabulary-head">head</loc>?, <loc href="#document-structure-vocabulary-body">body</loc>?
+&lt;/tt&gt;
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p>The <emph>Root Temporal Extent</emph>, i.e., the time interval over which a <emph>Document Instance</emph> is active, has an implicit duration that is equal to the
+implicit duration of the <el>body</el> element of the document, if the <el>body</el> element is present, or zero, if the <el>body</el> element is absent.</p>
+<p>If the <att>tts:extent</att> attribute is specified on the <el>tt</el>
+element, then it must adhere to <specref ref="style-attribute-extent"/>, in which case it
+specifies the spatial extent of the <emph>Root Container Region</emph> in
+which content regions are located and presented. If no <att>tts:extent</att>
+attribute is specified, then the spatial extent of the <emph>Root Container Region</emph> is
+considered to be determined by the <emph>Document Processing Context</emph>.
+The origin of the <emph>Root Container Region</emph> is determined by the <emph>Document Processing Context</emph>.</p>
+<note role="clarification">
+<p>In the absence of other requirements, and if a <emph>Related Media Object</emph> exists, then it is recommended
+that the <emph>Document Processing Context</emph> determine that:</p>
+<ulist>
+<item><p>if no <att>tts:extent</att> is specified on the root <el>tt</el> element, the extent of the <emph>Root Container Region</emph> be
+established as equal to the extent of the <emph>Related Media Object Region</emph>; and</p></item>
+<item><p>the origin of the <emph>Root Container Region</emph> be established so that this region is centered in the
+<emph>Related Media Object Region</emph>.</p></item>
+</ulist>
+</note>
+<note role="elaboration">
+<p>If an author desires to signal the (storage or image) aspect ratio of the <emph>Root Container Region</emph>
+without specifying its resolution, then this may be accomplished by using metadata specified
+in an external namespace, such as <att>m708:aspectRatio</att> as defined in <bibref ref="smpte2052"/>, &sect;5.4.4.
+This would permit, for example, the interchange of information that reflects the
+the semantics of <bibref ref="cea708d"/> , &sect;4.5 “Caption Service Metadata”, “ASPECT RATIO”.</p>
+</note>
+<p>An <att>xml:lang</att> attribute must be specified on the <el>tt</el> element.
+If the attribute value is empty, it signifies that there is no default language that applies
+to the text contained within the <emph>Document Instance</emph>.</p>
+<p>If no <att>xml:space</att> attribute is specified upon the <el>tt</el> element, then it must
+be considered as if the attribute had been specified with a value of <code>default</code>.</p>
+</div3>
+<div3 id="document-structure-vocabulary-head">
+<head>head</head>
+<p>The <el>head</el> element is a container element used to group
+header matter, including metadata,
+profile, styling, and layout information.</p>
+<p>The <el>head</el> element accepts as its children zero or more
+elements in the <code>Metadata.class</code> element group,
+followed by zero or more elements in the
+<code>Parameters.class</code> element group,
+followed by zero or one <el>styling</el> element,
+followed by zero or one <el>layout</el> element.</p>
+<p>Any metadata specified by children in the <code>Metadata.class</code>
+element group applies semantically to the <emph>Document Instance</emph> as a
+whole, and not just the <el>head</el> element.</p>
+<p>Any parameters specified by children in the <code>Parameters.class</code>
+element group applies semantically to the <emph>Document Instance</emph> as a
+whole, and not just the <el>head</el> element.</p>
+<p>A <el>styling</el> child element is used to specify style constructs
+that are referenced from other style constructs, by layout constructs, and by
+content elements.</p>
+<p>A <el>layout</el> child element is used to specify layout constructs that
+are referenced by content elements.</p>
+<table id="elt-syntax-head" role="syntax">
+<caption>XML Representation &ndash; Element Information Item: head</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;head
+  <loc href="#content-attribute-id">xml:id</loc> = ID
+  <loc href="#content-attribute-lang">xml:lang</loc> = string
+  <loc href="#content-attribute-space">xml:space</loc> = (<emph>default</emph>|<emph>preserve</emph>)
+  {<emph>any attribute not in default or any TT namespace</emph>}&gt;
+  <emph>Content:</emph> <loc href="#element-vocab-group-table">Metadata.class</loc>*, <loc href="#element-vocab-group-table">Parameters.class</loc>*, <loc href="#styling-vocabulary-styling">styling</loc>?, <loc href="#layout-vocabulary-layout">layout</loc>?
+&lt;/head&gt;
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p>To the extent that time semantics apply to the content of the
+<el>head</el> element, the implied time interval of this element is
+defined to be coterminous with the <emph>Root Temporal Extent</emph>.</p>
+</div3>
+<div3 id="document-structure-vocabulary-body">
+<head>body</head>
+<p>The <el>body</el> element functions as a logical container and a temporal
+structuring element for a sequence of textual content units represented as
+logical divisions.</p>
+<p>The <el>body</el> element accepts as its children zero or more
+elements in the <code>Metadata.class</code> element group,
+followed by zero or more
+elements in the <code>Animation.class</code> element group,
+followed by
+zero or more <el>div</el> elements.</p>
+<p>Any metadata specified by children in the <code>Metadata.class</code>
+element group applies semantically to the <el>body</el> element and its descendants as a whole.</p>
+<p>Any animation elements specified by children in the <code>Animation.class</code>
+element group apply semantically to the <el>body</el> element.</p>
+<table id="elt-syntax-body" role="syntax">
+<caption>XML Representation &ndash; Element Information Item: body</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;body
+  <loc href="#timing-attribute-begin">begin</loc> = <loc href="#timing-value-timeExpression">&lt;timeExpression&gt;</loc>
+  <loc href="#timing-attribute-dur">dur</loc> = <loc href="#timing-value-timeExpression">&lt;timeExpression&gt;</loc>
+  <loc href="#timing-attribute-end">end</loc> = <loc href="#timing-value-timeExpression">&lt;timeExpression&gt;</loc>
+  <loc href="#layout-attribute-region">region</loc> = IDREF
+  <loc href="#style-attribute-style">style</loc> = IDREFS
+  <loc href="#timing-attribute-timeContainer">timeContainer</loc> = (<emph>par</emph>|<emph>seq</emph>)
+  <loc href="#content-attribute-id">xml:id</loc> = ID
+  <loc href="#content-attribute-lang">xml:lang</loc> = string
+  <loc href="#content-attribute-space">xml:space</loc> = (<emph>default</emph>|<emph>preserve</emph>)
+  {<emph>any attribute in TT Metadata namespace</emph>}
+  {<emph>any attribute in TT Style namespace</emph>}
+  {<emph>any attribute not in default or any TT namespace</emph>}&gt;
+  <emph>Content:</emph> <loc href="#element-vocab-group-table">Metadata.class</loc>*, <loc href="#element-vocab-group-table">Animation.class</loc>*, <loc href="#content-vocabulary-div">div</loc>*
+&lt;/body&gt;
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p>An author may specify a temporal interval for a <el>body</el> element using
+the <att>begin</att>, <att>dur</att>, and <att>end</att> attributes. If the begin point
+of this interval remains unspecified, then the begin point is interpreted as the beginning
+point of the <emph>Root Temporal Extent</emph>. Similarly, if the end point of this interval remains unspecified, then the
+end point is interpreted as the ending point of the <emph>Root Temporal Extent</emph>.</p>
+<note role="explanation">
+<p>A <emph>Document Instance</emph> referenced from a SMIL presentation
+is expected to follow the same timing rules as apply to other SMIL media
+objects.</p>
+</note>
+<p>If relative begin or end times are specified on the <el>body</el>
+element, then these times are resolved by reference to the beginning and
+ending time of the <emph>Root Temporal Extent</emph>.</p>
+<p>If the <emph>Root Temporal Extent</emph> is shorter than the computed duration of the
+<el>body</el> element, then the active time interval of a <el>body</el> element is
+truncated to the active end point of the <emph>Root Temporal Extent</emph>.</p>
+<p>An author may associate a set of style properties with a
+<el>body</el> element by means of either the <att>style</att>
+attribute or inline style attributes or a combination thereof.</p>
+<note role="explanation">
+<p>Style properties that are associated with a <el>body</el> element
+in a <emph>Document Instance</emph> are available for style inheritance by
+descendant content elements such as <el>div</el>, <el>p</el>,
+<el>span</el>
+and <el>br</el>.</p>
+</note>
+<p>If no <att>timeContainer</att> attribute is specified on a
+<el>body</el> element, then it must be interpreted as having
+<emph>parallel</emph>
+time containment semantics.</p>
+</div3>
+<div3 id="content-vocabulary-div">
+<head>div</head>
+<p>The <el>div</el> element functions as a logical container and a temporal
+structuring element for a sequence of textual content units represented as
+logical sub-divisions or paragraphs.</p>
+<note role="explanation">
+<p>When rendered on a continuous (non-paged) visual presentation medium,
+a <el>div</el> element is expected to generate
+one or more block
+areas
+that contain zero or more child block areas
+generated by the <el>div</el> element's
+descendant
+<el>p</el> elements.
+</p>
+<p>If some
+block area generated by a <el>div</el> element does
+not contain any child areas, then it is not expected to be presented.</p>
+</note>
+<p>The <el>div</el> element accepts as its children zero or more
+elements in the <code>Metadata.class</code> element group,
+followed by zero or more
+elements in the <code>Animation.class</code> element group,
+followed by
+zero or more
+<el>div</el> or 
+<el>p</el> elements.</p>
+<p>Any metadata specified by children in the <code>Metadata.class</code>
+element group applies semantically to the <el>div</el> element and its descendants as a whole.</p>
+<p>Any animation elements specified by children in the <code>Animation.class</code>
+element group apply semantically to the <el>div</el> element.</p>
+<table id="elt-syntax-div" role="syntax">
+<caption>XML Representation &ndash; Element Information Item: div</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;div
+  <loc href="#timing-attribute-begin">begin</loc> = <loc href="#timing-value-timeExpression">&lt;timeExpression&gt;</loc>
+  <loc href="#timing-attribute-dur">dur</loc> = <loc href="#timing-value-timeExpression">&lt;timeExpression&gt;</loc>
+  <loc href="#timing-attribute-end">end</loc> = <loc href="#timing-value-timeExpression">&lt;timeExpression&gt;</loc>
+  <loc href="#layout-attribute-region">region</loc> = IDREF
+  <loc href="#style-attribute-style">style</loc> = IDREFS
+  <loc href="#timing-attribute-timeContainer">timeContainer</loc> = (<emph>par</emph>|<emph>seq</emph>)
+  <loc href="#content-attribute-id">xml:id</loc> = ID
+  <loc href="#content-attribute-lang">xml:lang</loc> = string
+  <loc href="#content-attribute-space">xml:space</loc> = (<emph>default</emph>|<emph>preserve</emph>)
+  {<emph>any attribute in TT Metadata namespace</emph>}
+  {<emph>any attribute in TT Style namespace</emph>}
+  {<emph>any attribute not in default or any TT namespace</emph>}&gt;
+  <emph>Content:</emph> <loc
+  href="#element-vocab-group-table">Metadata.class</loc>*, <loc
+  href="#element-vocab-group-table">Animation.class</loc>*, <loc
+  href="#element-vocab-group-table">Block.class</loc>*
+&lt;/div&gt;
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p>An author may associate a set of style properties with a <el>div</el> element by means of either
+the <att>style</att> attribute or inline style attributes or a combination thereof.</p>
+<note role="explanation">
+<p>Style properties that are associated
+with
+a <el>div</el> element in a <emph>Document Instance</emph>
+are available for style inheritance by descendant content elements such as
+<el>div</el>, 
+<el>p</el>,
+<el>span</el>, and
+<el>br</el>.</p>
+</note>
+<p>If no <att>timeContainer</att> attribute is specified on
+a <el>div</el> element, then it must be interpreted as having
+<emph>parallel</emph> time containment semantics.</p>
+</div3>
+<div3 id="content-vocabulary-p">
+<head>p</head>
+<p>A <el>p</el> element represents a logical paragraph, serving as
+a transition between block level and inline level formatting semantics.</p>
+<p>The <el>p</el> element accepts as its children zero or more
+elements in the <code>Metadata.class</code> element group,
+followed by zero or more
+elements in the <code>Animation.class</code> element group,
+followed by
+zero or more intermixed
+<code>span</code> elements,
+<code>br</code> elements,
+or text nodes interpreted as an anonymous spans.</p>
+<p>Any metadata specified by children in the <code>Metadata.class</code>
+element group applies semantically to the <el>p</el> element and its descendants as a whole.</p>
+<p>Any animation elements specified by children in the <code>Animation.class</code>
+element group apply semantically to the <el>p</el> element.</p>
+<table id="elt-syntax-p" role="syntax">
+<caption>XML Representation &ndash; Element Information Item: p</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;p
+  <loc href="#timing-attribute-begin">begin</loc> = <loc href="#timing-value-timeExpression">&lt;timeExpression&gt;</loc>
+  <loc href="#timing-attribute-dur">dur</loc> = <loc href="#timing-value-timeExpression">&lt;timeExpression&gt;</loc>
+  <loc href="#timing-attribute-end">end</loc> = <loc href="#timing-value-timeExpression">&lt;timeExpression&gt;</loc>
+  <loc href="#layout-attribute-region">region</loc> = IDREF
+  <loc href="#style-attribute-style">style</loc> = IDREFS
+  <loc href="#timing-attribute-timeContainer">timeContainer</loc> = (<emph>par</emph>|<emph>seq</emph>)
+  <loc href="#content-attribute-id">xml:id</loc> = ID
+  <loc href="#content-attribute-lang">xml:lang</loc> = string
+  <loc href="#content-attribute-space">xml:space</loc> = (<emph>default</emph>|<emph>preserve</emph>)
+  {<emph>any attribute in TT Metadata namespace</emph>}
+  {<emph>any attribute in TT Style namespace</emph>}
+  {<emph>any attribute not in default or any TT namespace</emph>}&gt;
+  <emph>Content:</emph> <loc
+  href="#element-vocab-group-table">Metadata.class</loc>*, <loc
+  href="#element-vocab-group-table">Animation.class</loc>*, <loc
+  href="#element-vocab-group-table">Inline.class</loc>*
+&lt;/p&gt;
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p>An author may associate a set of style properties with a
+<el>p</el> element by means of either the <att>style</att>
+attribute or inline style attributes or a combination thereof.</p>
+<note role="explanation">
+<p>Style properties that are associated with a <el>p</el> element
+in a <emph>Document Instance</emph> are available for style inheritance by
+descendant content elements such as <el>span</el> and
+<el>br</el>.</p>
+</note>
+<p>If no <att>timeContainer</att> attribute is specified on
+a <el>p</el> element, then it must be interpreted as having
+<emph>parallel</emph> time containment semantics.</p>
+<p>If a sequence of children of a <el>p</el> element
+consists solely of character information items, then that sequence must
+be considered to be an <emph>anonymous span</emph> for the purpose of
+applying style properties that apply to <el>span</el> elements.</p>
+<note role="elaboration"><p>The presentation semantics of TTML effectively
+implies that a <el>p</el> element constitutes a line break. In particular,
+it is associated with a block-stacking constraint both before the first
+generated line area and after the last generated line area. See
+<specref ref="semantics-region-layout-step-2"/> for further details.</p>
+</note>
+</div3>
+<div3 id="content-vocabulary-span">
+<head>span</head>
+<p>The <el>span</el> element functions as a logical container and a temporal
+structuring element for a sequence of textual content units having inline
+level formatting semantics.</p>
+<p>When presented on a visual medium, a <el>span</el> element is intended to
+generate a sequence of inline areas, each containing one or more glyph areas.</p>
+<p>The <el>span</el> element accepts as its children zero or more
+elements in the <code>Metadata.class</code> element group,
+followed by zero or more
+elements in the <code>Animation.class</code> element group,
+followed by
+zero or more intermixed
+<el>span</el> elements,
+<el>br</el> elements,
+or text nodes interpreted as anonymous spans.</p>
+<p>Any metadata specified by children in the <code>Metadata.class</code>
+element group applies semantically to the <el>span</el> element and its descendants as a whole.</p>
+<p>Any animation elements specified by children in the <code>Animation.class</code>
+element group apply semantically to the <el>span</el> element.</p>
+<table id="elt-syntax-span" role="syntax">
+<caption>XML Representation &ndash; Element Information Item: span</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;span
+  <loc href="#timing-attribute-begin">begin</loc> = <loc href="#timing-value-timeExpression">&lt;timeExpression&gt;</loc>
+  <loc href="#timing-attribute-dur">dur</loc> = <loc href="#timing-value-timeExpression">&lt;timeExpression&gt;</loc>
+  <loc href="#timing-attribute-end">end</loc> = <loc href="#timing-value-timeExpression">&lt;timeExpression&gt;</loc>
+  <loc href="#layout-attribute-region">region</loc> = IDREF
+  <loc href="#style-attribute-style">style</loc> = IDREFS
+  <loc href="#timing-attribute-timeContainer">timeContainer</loc> = (<emph>par</emph>|<emph>seq</emph>)
+  <loc href="#content-attribute-id">xml:id</loc> = ID
+  <loc href="#content-attribute-lang">xml:lang</loc> = string
+  <loc href="#content-attribute-space">xml:space</loc> = (<emph>default</emph>|<emph>preserve</emph>)
+  {<emph>any attribute in TT Metadata namespace</emph>}
+  {<emph>any attribute in TT Style namespace</emph>}
+  {<emph>any attribute not in default or any TT namespace</emph>}&gt;
+  <emph>Content:</emph> <loc
+  href="#element-vocab-group-table">Metadata.class</loc>*, <loc
+  href="#element-vocab-group-table">Animation.class</loc>*, <loc
+  href="#element-vocab-group-table">Inline.class</loc>*
+&lt;/span&gt;
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p>An author may associate a set of style properties with a
+<el>span</el> element by means of either the <att>style</att>
+attribute or inline style attributes or a combination thereof.</p>
+<note role="explanation">
+<p>Style properties that are associated with a <el>span</el> element
+in a <emph>Document Instance</emph> are available for style inheritance by
+descendant content elements such as <el>span</el> and
+<el>br</el>.</p>
+</note>
+<p>If no <att>timeContainer</att> attribute is specified on
+a <el>span</el> element, then it must be interpreted as having
+<emph>parallel</emph> time containment semantics.</p>
+</div3>
+<div3 id="content-vocabulary-br">
+<head>br</head>
+<p>The <el>br</el> element denotes an explicit line break.</p>
+<table id="elt-syntax-br" role="syntax">
+<caption>XML Representation &ndash; Element Information Item: br</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;br
+  <loc href="#style-attribute-style">style</loc> = IDREFS
+  <loc href="#content-attribute-id">xml:id</loc> = ID
+  <loc href="#content-attribute-lang">xml:lang</loc> = string
+  <loc href="#content-attribute-space">xml:space</loc> = (<emph>default</emph>|<emph>preserve</emph>)
+  {<emph>any attribute in TT Metadata namespace</emph>}
+  {<emph>any attribute in TT Style namespace</emph>}
+  {<emph>any attribute not in default or any TT namespace</emph>}&gt;
+  <emph>Content:</emph> <loc href="#element-vocab-group-table">Metadata.class</loc>*, <loc href="#element-vocab-group-table">Animation.class</loc>*
+&lt;/br&gt;
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p>When presented on a visual medium, the presence of a <el>br</el> element must be
+interpreted as a forced line break.</p>
+<note>
+<p>The visual presentation of a <el>br</el> element is
+intended to produce the same effect as the control character
+<code>CR</code> (U+000D)
+followed by the control code <code>LF</code> (U+000A) when presented on a teletype device.
+Therefore, two <el>br</el> elements in sequence will produce a
+different effect than a single <el>br</el> element.</p>
+</note>
+</div3>
+</div2>
+<div2 id="content-attribute-vocabulary">
+<head>Content Attribute Vocabulary</head>
+<p>This section defines the following common attributes used with many or all element types
+in the core vocabulary catalog:</p>
+<ulist>
+<item><p><specref ref="content-attribute-id"/></p></item>
+<item><p><specref ref="content-attribute-lang"/></p></item>
+<item><p><specref ref="content-attribute-space"/></p></item>
+</ulist>
+<div3 id="content-attribute-id">
+<head>xml:id</head>
+<p>The <att>xml:id</att> attribute is used as defined by
+<bibref ref="xmlid"/>.</p>
+<p>The <att>xml:id</att> attribute may be used with any element in the
+core vocabulary catalog.</p>
+</div3>
+<div3 id="content-attribute-lang">
+<head>xml:lang</head>
+<p>The <att>xml:lang</att> attribute is used as defined by
+<bibref ref="xml10"/>, &sect;2.12, <emph>Language Identification</emph>.</p>
+<p>The <att>xml:lang</att> attribute must be specified on the <el>tt</el>
+element and may be specified by an instance of any other element type
+in the core vocabulary catalog except parameter vocabulary.</p>
+</div3>
+<div3 id="content-attribute-space">
+<head>xml:space</head>
+<p>The <att>xml:space</att> attribute is used as defined by
+<bibref ref="xml10"/>, &sect;2.10, <emph>White Space Handling</emph>.</p>
+<p>The <att>xml:space</att> attribute may be used with any element in
+the core vocabulary catalog except parameter vocabulary.</p>
+<p>The semantics of the value <code>default</code> are fixed to mean that
+when performing presentation processing of a <emph>Document Instance</emph> as
+described by <specref ref="semantics-region-layout-step-2"/>,
+processing must occur as
+if the following properties were specified on the affected
+elements of an equivalent intermediate XSL-FO document:</p>
+<ulist>
+<item>
+<p><code>suppress-at-line-break="auto"</code></p>
+</item>
+<item>
+<p><code>linefeed-treatment="treat-as-space"</code></p>
+</item>
+<item>
+<p><code>white-space-collapse="true"</code></p>
+</item>
+<item>
+<p><code>white-space-treatment="ignore-if-surrounding-linefeed"</code></p>
+</item>
+</ulist>
+<p>Similarly, the semantics of the value <code>preserve</code> are fixed to mean that
+when performing presentation processing, processing must occur as
+if the following properties were specified on the affected
+elements of an equivalent intermediate XSL-FO document:
+</p>
+<ulist>
+<item>
+<p><code>suppress-at-line-break="retain"</code></p>
+</item>
+<item>
+<p><code>linefeed-treatment="preserve"</code></p>
+</item>
+<item>
+<p><code>white-space-collapse="false"</code></p>
+</item>
+<item>
+<p><code>white-space-treatment="preserve"</code></p>
+</item>
+</ulist>
+<p>When performing other types of processing intended to eventually
+result in a visual presentation by means other than those described
+in this specification, the semantics of space collapsing and
+preservation as described above should be respected. For other types
+of processing, the treatment of the <att>xml:space</att> attribute
+is processor dependent, but should respect the semantics described
+above if possible.</p>
+<note role="derivation">
+<p>The semantics of the above four cited XSL-FO properties are defined by
+by <bibref ref="xsl11"/>, &sect; 7.17.3, 7.16.7, 7.16.12, and 7.16.8, respectively.</p>
+</note>
+</div3>
+</div2>
+</div1>
+<div1 id="styling">
+<head>Styling</head>
+<p>This section specifies the <emph>styling</emph> matter of the core
+vocabulary catalog, where
+styling is to be understood as a separable layer of information that applies to
+content and that denotes authorial intentions about the presentation of
+that content.</p>
+<p>Styling attributes are included in TTML to enable authorial intent of presentation
+to be included within a self-contained document. This section describes
+the semantics of style presentation in terms of a standard processing
+model. TTML Processors are not required to present <emph>Document Instances</emph> in any particular way; 
+but an implementation of this model by a TTML Presentation Processor
+that provides externally observable results that are consistent with this model is
+likely to lead to a user experience that closely resembles the experience intended by
+the documents' authors.</p>
+<p>The semantics of TTML style presentation are described in terms of the model 
+in <bibref ref="xsl11"/>. The effects of the attributes in this section 
+are intended to be compatible with the layout and formatting model of XSL; however, Presentation agents
+may use any technology to satisfy the authorial intent of the document. In particular 
+since <bibref ref="css2"/> is a subset of this model, a CSS processor may be used 
+for the features that the models have in common.</p>
+<p>No normative use of an
+<code>&lt;?xml-stylesheet ... ?&gt;</code> processing instruction is defined
+by this specification.</p>
+<div2 id="styling-element-vocabulary">
+<head>Styling Element Vocabulary</head>
+<p>The following elements specify the structure and principal styling aspects of a
+<emph>Document Instance</emph>:</p>
+<ulist>
+<item><p><specref ref="styling-vocabulary-styling"/></p></item>
+<item><p><specref ref="styling-vocabulary-style"/></p></item>
+</ulist>
+<div3 id="styling-vocabulary-styling">
+<head>styling</head>
+<p>The <el>styling</el> element is a container element used to group
+styling matter, including metadata that applies to styling matter.</p>
+<p>The <el>styling</el> element accepts as its children zero or more
+elements in the <code>Metadata.class</code> element group, followed by
+zero or more <el>style</el> elements.</p>
+<table id="elt-syntax-styling" role="syntax">
+<caption>XML Representation &ndash; Element Information Item: styling</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;styling
+  <loc href="#content-attribute-id">xml:id</loc> = ID
+  <loc href="#content-attribute-lang">xml:lang</loc> = string
+  <loc href="#content-attribute-space">xml:space</loc> = (<emph>default</emph>|<emph>preserve</emph>)
+  {<emph>any attribute not in default or any TT namespace</emph>}&gt;
+  <emph>Content:</emph> <loc href="#element-vocab-group-table">Metadata.class</loc>*, <loc href="#styling-vocabulary-style">style</loc>*
+&lt;/styling&gt;
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p>To the extent that time semantics apply to the content of the
+<el>styling</el> element, the implied time interval of this element is
+defined to be coterminous with the <emph>Root Temporal Extent</emph>.</p>
+</div3>
+<div3 id="styling-vocabulary-style">
+<head>style</head>
+<p>The <el>style</el> element is used to define
+a set of style specifications expressed as a
+specified style set in accordance with
+<specref ref="semantics-style-resolution-processing-sss"/>.</p>
+<p>The <el>style</el> element accepts as its children zero or more <el>metadata</el> elements.</p>
+<table id="elt-syntax-style" role="syntax">
+<caption>XML Representation &ndash; Element Information Item: style</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;style
+  <loc href="#style-attribute-style">style</loc> = IDREFS
+  <loc href="#content-attribute-id">xml:id</loc> = ID
+  <loc href="#content-attribute-lang">xml:lang</loc> = string
+  <loc href="#content-attribute-space">xml:space</loc> = (<emph>default</emph>|<emph>preserve</emph>)
+  {<emph>any attribute in TT Style namespace</emph>}
+  {<emph>any attribute not in default or any TT namespace</emph>}&gt;
+ <emph>Content:</emph> EMPTY
+&lt;/style&gt;
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p>If a <el>style</el> element appears as a descendant of a
+<el>region</el> element, then the <el>style</el> element must be
+ignored for the purpose of computing referential styles as defined by
+<specref ref="semantics-style-association-referential"/> and <specref
+ref="semantics-style-association-chained-referential"/>.</p>
+<note role="explanation">
+<p>That is to say, when referential styling is used by an element to
+refer to a <el>style</el> element, then the referenced <el>style</el>
+element must appear as a descendant of the <el>styling</el> element, and
+not in any other context.</p>
+</note>
+</div3>
+</div2>
+<div2 id="styling-attribute-vocabulary">
+<head>Styling Attribute Vocabulary</head>
+<p>This section defines the <specref ref="style-attribute-style"/> attribute used
+with both style definition elements as well as content elements.</p>
+<p>In addition, this section specifies the following attributes in the TT Style Namespace
+for use with style definition elements, certain layout elements, and content elements
+that support inline style specifications:</p>
+<ulist>
+<item><p><specref ref="style-attribute-backgroundColor"/></p></item>
+<item><p><specref ref="style-attribute-color"/></p></item>
+<item><p><specref ref="style-attribute-direction"/></p></item>
+<item><p><specref ref="style-attribute-display"/></p></item>
+<item><p><specref ref="style-attribute-displayAlign"/></p></item>
+<item><p><specref ref="style-attribute-extent"/></p></item>
+<item><p><specref ref="style-attribute-fontFamily"/></p></item>
+<item><p><specref ref="style-attribute-fontSize"/></p></item>
+<item><p><specref ref="style-attribute-fontStyle"/></p></item>
+<item><p><specref ref="style-attribute-fontWeight"/></p></item>
+<item><p><specref ref="style-attribute-lineHeight"/></p></item>
+<item><p><specref ref="style-attribute-opacity"/></p></item>
+<item><p><specref ref="style-attribute-origin"/></p></item>
+<item><p><specref ref="style-attribute-overflow"/></p></item>
+<item><p><specref ref="style-attribute-padding"/></p></item>
+<item><p><specref ref="style-attribute-showBackground"/></p></item>
+<item><p><specref ref="style-attribute-textAlign"/></p></item>
+<item><p><specref ref="style-attribute-textDecoration"/></p></item>
+<item><p><specref ref="style-attribute-textOutline"/></p></item>
+<item><p><specref ref="style-attribute-unicodeBidi"/></p></item>
+<item><p><specref ref="style-attribute-visibility"/></p></item>
+<item><p><specref ref="style-attribute-wrapOption"/></p></item>
+<item><p><specref ref="style-attribute-writingMode"/></p></item>
+<item><p><specref ref="style-attribute-zIndex"/></p></item>
+</ulist>
+<p>Unless explicitly stated otherwise, linear white-space (LWSP) must
+appear between adjacent non-terminal components of a value of a TT
+Style or TT Style Extension
+Property value unless some other delimiter is permitted and used.</p>
+<note role="explanation">
+<p>This specification makes use of <emph>lowerCamelCased</emph> local
+names for style attributes that
+are based upon like-named properties defined by <bibref ref="xsl11"/>.
+This convention is likewise extended to token values of such
+properties.</p>
+</note>
+<note role="clarification">
+<p>A style property may be expressed as a specified attribute on any content
+element type independently of whether the property applies to that
+element type. This capability permits the expression of an inheritable
+style property on ancestor elements to which the property
+does not apply.</p>
+</note>
+<div3 id="style-attribute-style">
+<head>style</head>
+<p>The <att>style</att> attribute is used by referential style association
+to reference one or more <el>style</el> elements each of which define a style (property) set.</p>
+<p>The <att>style</att> attribute may be specified by an instance of the following
+element types:</p>
+<ulist>
+<item><p><loc href="#document-structure-vocabulary-body"><el>body</el></loc></p></item>
+<item><p><loc href="#content-vocabulary-div"><el>div</el></loc></p></item>
+<item><p><loc href="#content-vocabulary-p"><el>p</el></loc></p></item>
+<item><p><loc href="#layout-vocabulary-region"><el>region</el></loc></p></item>
+<item><p><loc href="#content-vocabulary-span"><el>span</el></loc></p></item>
+<item><p><loc href="#styling-vocabulary-style"><el>style</el></loc></p></item>
+</ulist>
+<p>If specified, the value of a <att>style</att> attribute must
+adhere to the <code>IDREFS</code> data type defined by <bibref ref="xsd-2"/>,
+&sect; 3.3.10, and, furthermore, each IDREF must reference a <el>style</el> element
+which has a <el>styling</el> element as an ancestor.</p>
+<p>If the same IDREF, <emph>ID<sub>1</sub></emph>, appears more than one time in the value of a <att>style</att>
+attribute, then there should be an intervening IDREF, <emph>ID<sub>2</sub></emph>, where 
+<emph>ID<sub>2</sub></emph> is not equal to <emph>ID<sub>1</sub></emph>.</p>
+<note role="explanation">
+<p>This constraint is intended to discourage the use of redundant referential styling while still
+allowing the same style to be referenced multiple times in order to potentially override prior
+referenced styles, e.g., when an intervening, distinct style is referenced in the IDREFS list.</p>
+</note>
+<note role="usage">
+<p>See the specific element type definitions that permit use of the
+<att>style</att> attribute, as well as <specref
+ref="semantics-style-association-referential"/> and <specref
+ref="semantics-style-association-chained-referential"/>, for
+further information on its semantics.</p>
+</note>
+</div3>
+<div3 id="style-attribute-backgroundColor">
+<head>tts:backgroundColor</head>
+<p>The <att>tts:backgroundColor</att> attribute is used to specify a style property that
+defines the background color of a region or an area generated by content flowed into a region.</p>
+<p>This attribute may be specified by any
+element type
+that permits use of attributes in the TT Style Namespace; however, this attribute applies
+as a style property only to those element types indicated in the following table.</p>
+<table id="style-property-details-backgroundColor" role="common">
+<col width="25%"/>
+<col/>
+<tbody>
+<tr>
+<td><emph>Values:</emph></td>
+<td>
+<loc href="#style-value-color">&lt;color&gt;</loc>
+</td>
+</tr>
+<tr>
+<td><emph>Initial:</emph></td>
+<td><code>transparent</code></td>
+</tr>
+<tr>
+<td><emph>Applies to:</emph></td>
+<td>
+<loc href="#document-structure-vocabulary-body"><el>body</el></loc>,
+<loc href="#content-vocabulary-div"><el>div</el></loc>,
+<loc href="#content-vocabulary-p"><el>p</el></loc>,
+<loc href="#layout-vocabulary-region"><el>region</el></loc>,
+<loc href="#content-vocabulary-span"><el>span</el></loc>
+</td>
+</tr>
+<tr>
+<td><emph>Inherited:</emph></td>
+<td>no</td>
+</tr>
+<tr>
+<td><emph>Percentages:</emph></td>
+<td>N/A</td>
+</tr>
+<tr>
+<td><emph>Animatable:</emph></td>
+<td>discrete</td>
+</tr>
+</tbody>
+</table>
+<p>For the purpose of determining applicability of this style property,
+each character child of a <el>p</el> element is considered to be enclosed in an anonymous
+span.</p>
+<p>The <att>tts:backgroundColor</att> style is illustrated by the following example.</p>
+<table id="style-attribute-backgroundColor-example-1" role="example">
+<caption>Example Fragment &ndash; Background Color</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;region xml:id="r1"&gt;
+  &lt;style tts:extent="306px 114px"/&gt;
+  &lt;style <phrase role="strong">tts:backgroundColor="red"</phrase>/&gt;
+  &lt;style tts:color="white"/&gt;
+  &lt;style tts:displayAlign="after"/&gt;
+  &lt;style tts:padding="3px 40px"/&gt;
+&lt;/region&gt;
+...
+&lt;p region="r1" <phrase role="strong">tts:backgroundColor="purple"</phrase> tts:textAlign="center"&gt;
+  Twinkle, twinkle, little bat!&lt;br/&gt;
+  How &lt;span <phrase role="strong">tts:backgroundColor="green"</phrase>&gt;I wonder&lt;/span&gt; where you're at!
+&lt;/p&gt;
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p></p>
+<table id="style-attribute-backgroundColor-example-1-images" role="example-images">
+<caption>Example Rendition &ndash; Background Color</caption>
+<tbody>
+<tr>
+<td><graphic source="images/backgroundColor.png" alt="TTML backgroundColor style property"/></td>
+</tr>
+</tbody>
+</table>
+<note role="derivation">
+<p>The semantics of the style property represented by this attribute are based upon 
+that defined by <bibref ref="xsl11"/>, &sect; 7.8.2.</p>
+</note>
+</div3>
+<div3 id="style-attribute-color">
+<head>tts:color</head>
+<p>The <att>tts:color</att> attribute is used to specify a style property that
+defines the foreground color of marks associated with an area generated by content flowed into a region.</p>
+<p>This attribute may be specified by any
+element type
+that permits use of attributes in the TT Style Namespace; however, this attribute applies
+as a style property only to those element types indicated in the following table.</p>
+<table id="style-property-details-color" role="common">
+<col width="25%"/>
+<col/>
+<tbody>
+<tr>
+<td><emph>Values:</emph></td>
+<td>
+<loc href="#style-value-color">&lt;color&gt;</loc>
+</td>
+</tr>
+<tr>
+<td><emph>Initial:</emph></td>
+<td>see prose</td>
+</tr>
+<tr>
+<td><emph>Applies to:</emph></td>
+<td>
+<loc href="#content-vocabulary-span"><el>span</el></loc>
+</td>
+</tr>
+<tr>
+<td><emph>Inherited:</emph></td>
+<td>yes</td>
+</tr>
+<tr>
+<td><emph>Percentages:</emph></td>
+<td>N/A</td>
+</tr>
+<tr>
+<td><emph>Animatable:</emph></td>
+<td>discrete</td>
+</tr>
+</tbody>
+</table>
+<p>For the purpose of determining applicability of this style property,
+each character child of a <el>p</el> element is considered to be enclosed in an anonymous
+span.</p>
+<p>The initial value of the <att>tts:color</att> property
+is considered to be implementation dependent. In the absence of
+end-user preference information, a conformant presentation processor
+should use an initial value that is highly contrastive to the
+background color of the <emph>Root Container Region</emph>.</p>
+<p>The <att>tts:color</att> style is illustrated by the following example.</p>
+<table id="style-attribute-color-example-1" role="example">
+<caption>Example Fragment &ndash; Color</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;region xml:id="r1"&gt;
+  &lt;style tts:backgroundColor="black"/&gt;
+  &lt;style <phrase role="strong">tts:color="white"</phrase>/&gt;
+  &lt;style tts:displayAlign="after"/&gt;
+  &lt;style tts:textAlign="center"/&gt;
+&lt;/region&gt;
+...
+&lt;p region="r1"&gt;
+  In spring, when woods are &lt;span <phrase role="strong">tts:color="green"</phrase>&gt;getting green&lt;/span&gt;,&lt;br/&gt;
+  I'll try and tell you what I mean.
+&lt;/p&gt;
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p></p>
+<table id="style-attribute-color-example-1-images" role="example-images">
+<caption>Example Rendition &ndash; Color</caption>
+<tbody>
+<tr>
+<td><graphic source="images/color.png" alt="TTML color style property"/></td>
+</tr>
+</tbody>
+</table>
+ <note role="derivation">
+<p>The semantics of the style property
+represented by this attribute are based upon that defined by <bibref ref="xsl11"/>,
+&sect; 7.18.1.</p>
+</note>
+</div3>
+<div3 id="style-attribute-direction">
+<head>tts:direction</head>
+<p>The <att>tts:direction</att> attribute is used to specify a style property that
+defines the directionality of an embedding or override according to
+the Unicode bidirectional algorithm.</p>
+<p>This attribute may be specified by any
+element type
+that permits use of attributes in the TT Style Namespace; however, this attribute applies
+as a style property only to those element types indicated in the following table.</p>
+<table id="style-property-details-direction" role="common">
+<col width="25%"/>
+<col/>
+<tbody>
+<tr>
+<td><emph>Values:</emph></td>
+<td>
+<code>ltr</code> |
+<code>rtl</code>
+</td>
+</tr>
+<tr>
+<td><emph>Initial:</emph></td>
+<td>
+<code>ltr</code>
+</td>
+</tr>
+<tr>
+<td><emph>Applies to:</emph></td>
+<td>
+<loc href="#content-vocabulary-p"><el>p</el></loc>,
+<loc href="#content-vocabulary-span"><el>span</el></loc>
+</td>
+</tr>
+<tr>
+<td><emph>Inherited:</emph></td>
+<td>yes</td>
+</tr>
+<tr>
+<td><emph>Percentages:</emph></td>
+<td>N/A</td>
+</tr>
+<tr>
+<td><emph>Animatable:</emph></td>
+<td>discrete</td>
+</tr>
+</tbody>
+</table>
+<p>For the purpose of determining applicability of this style property,
+each character child of a <el>p</el> element is considered to be enclosed in an anonymous
+span.</p>
+<p>If a specified value of this attribute is not supported,
+then a presentation processor must ignore the attribute.</p>
+<p>The <att>tts:direction</att> style is illustrated by the following example.</p>
+<table id="style-attribute-direction-example-1" role="example">
+<caption>Example Fragment &ndash; Direction</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;region xml:id="r1"&gt;
+  &lt;style tts:extent="265px 84px"/&gt;
+  &lt;style tts:padding="5px"/&gt;
+  &lt;style tts:backgroundColor="black"/&gt;
+  &lt;style tts:color="white"/&gt;
+  &lt;style tts:displayAlign="after"/&gt;
+  &lt;style tts:textAlign="center"/&gt;
+&lt;/region&gt;
+...
+&lt;p region="r1"&gt;
+  Little birds are playing&lt;br/&gt;
+  Bagpipes on the shore,&lt;br/&gt;
+  &lt;span tts:unicodeBidi="bidiOverride" <phrase role="strong">tts:direction="rtl"</phrase>&gt;where the tourists snore.&lt;/span&gt;
+&lt;/p&gt;
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p></p>
+<table id="style-attribute-direction-example-1-images" role="example-images">
+<caption>Example Rendition &ndash; Direction</caption>
+<tbody>
+<tr>
+<td>
+<graphic source="images/direction.png" alt="TTML direction style property"/>
+</td>
+</tr>
+</tbody>
+</table>
+<note role="derivation">
+<p>The semantics of the style property
+represented by this attribute are based upon that defined by <bibref ref="xsl11"/>,
+&sect; 7.29.1.</p>
+</note>
+</div3>
+<div3 id="style-attribute-display">
+<head>tts:display</head>
+<p>The <att>tts:display</att> attribute is used to specify a style property that
+defines whether an element is a candidate for layout and composition
+in a region.</p>
+<p>This attribute may be specified by any
+element type
+that permits use of attributes in the TT Style Namespace; however, this attribute applies
+as a style property only to those element types indicated in the following table.</p>
+<table id="style-property-details-display" role="common">
+<col width="25%"/>
+<col/>
+<tbody>
+<tr>
+<td><emph>Values:</emph></td>
+<td>
+<code>auto</code> |
+<code>none</code>
+</td>
+</tr>
+<tr>
+<td><emph>Initial:</emph></td>
+<td>
+<code>auto</code>
+</td>
+</tr>
+<tr>
+<td><emph>Applies to:</emph></td>
+<td>
+<loc href="#document-structure-vocabulary-body"><el>body</el></loc>,
+<loc href="#content-vocabulary-div"><el>div</el></loc>,
+<loc href="#content-vocabulary-p"><el>p</el></loc>,
+<loc href="#layout-vocabulary-region"><el>region</el></loc>,
+<loc href="#content-vocabulary-span"><el>span</el></loc>
+</td>
+</tr>
+<tr>
+<td><emph>Inherited:</emph></td>
+<td>no</td>
+</tr>
+<tr>
+<td><emph>Percentages:</emph></td>
+<td>N/A</td>
+</tr>
+<tr>
+<td><emph>Animatable:</emph></td>
+<td>discrete</td>
+</tr>
+</tbody>
+</table>
+<p>For the purpose of determining applicability of this style property,
+each character child of a <el>p</el> element is considered to be enclosed in an anonymous
+span.</p>
+<p>If the value of this attribute is <code>auto</code>,
+then the affected element is a candidate for region layout and
+presentation; however, if the value is <code>none</code>, then the
+affected element and its descendants must be considered ineligible for region
+layout and presentation.</p>
+<p>The <att>tts:display</att> style is illustrated by the following example.</p>
+<table id="style-attribute-display-example-1" role="example">
+<caption>Example Fragment &ndash; Display</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;region xml:id="r1"&gt;
+  &lt;style tts:extent="369px 119px"
+            tts:backgroundColor="black"
+            tts:color="white"
+            tts:displayAlign="before"
+            tts:textAlign="start"/&gt;
+&lt;/region&gt;
+...
+&lt;div region="r1"&gt;
+  &lt;p dur="5s"&gt;
+    [[[
+    &lt;span <phrase role="strong">tts:display="none"</phrase>&gt;
+      &lt;set begin="1s" dur="1s" <phrase role="strong">tts:display="auto"</phrase>/&gt;
+      Beautiful soup,
+    &lt;/span&gt;
+    &lt;span <phrase role="strong">tts:display="none"</phrase>&gt;
+      &lt;set begin="2s" dur="1s" <phrase role="strong">tts:display="auto"</phrase>/&gt;
+      so rich and green,
+    &lt;/span&gt;
+    &lt;span <phrase role="strong">tts:display="none"</phrase>&gt;
+      &lt;set begin="3s" dur="1s" <phrase role="strong">tts:display="auto"</phrase>/&gt;
+      waiting in a hot tureen!
+    &lt;/span&gt;
+    ]]]
+  &lt;/p&gt;
+&lt;/div&gt;
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p></p>
+<table id="style-attribute-display-example-1-images" role="example-images">
+<caption>Example Rendition &ndash; Display</caption>
+<tbody>
+<tr>
+<td>
+<graphic source="images/display_0.png" alt="TTML display style property - [0,1)"/>
+</td>
+</tr>
+<tr>
+<td>
+<graphic source="images/display_1.png" alt="TTML display style property - [1,2)"/>
+</td>
+</tr>
+<tr>
+<td>
+<graphic source="images/display_2.png" alt="TTML display style property - [2,3)"/>
+</td>
+</tr>
+<tr>
+<td>
+<graphic source="images/display_3.png" alt="TTML display style property - [3,4)"/>
+</td>
+</tr>
+<tr>
+<td>
+<graphic source="images/display_4.png" alt="TTML display style property - [4,5)"/>
+</td>
+</tr>
+</tbody>
+</table>
+<note role="derivation">
+<p>The semantics of the style property
+represented by this attribute are based upon that defined by <bibref ref="css2"/>, &sect; 9.2.4.</p>
+</note>
+</div3>
+<div3 id="style-attribute-displayAlign">
+<head>tts:displayAlign</head>
+<p>The <att>tts:displayAlign</att> attribute is used to specify a style property that
+defines the alignment of block areas in the block progression direction.</p>
+<p>This attribute may be specified by any
+element type
+that permits use of attributes in the TT Style Namespace; however, this attribute applies
+as a style property only to those element types indicated in the following table.</p>
+<table id="style-property-details-displayAlign" role="common">
+<col width="25%"/>
+<col/>
+<tbody>
+<tr>
+<td><emph>Values:</emph></td>
+<td>
+<code>before</code> |
+<code>center</code> |
+<code>after</code>
+</td>
+</tr>
+<tr>
+<td><emph>Initial:</emph></td>
+<td>
+<code>before</code>
+</td>
+</tr>
+<tr>
+<td><emph>Applies to:</emph></td>
+<td>
+<loc href="#layout-vocabulary-region"><el>region</el></loc>
+</td>
+</tr>
+<tr>
+<td><emph>Inherited:</emph></td>
+<td>no</td>
+</tr>
+<tr>
+<td><emph>Percentages:</emph></td>
+<td>N/A</td>
+</tr>
+<tr>
+<td><emph>Animatable:</emph></td>
+<td>discrete</td>
+</tr>
+</tbody>
+</table>
+<p>If a specified value of this attribute is not supported,
+then a presentation processor must interpret the attribute as if the
+value <code>before</code> were specified.</p>
+<p>The <att>tts:displayAlign</att> style is illustrated by the following example.</p>
+<table id="style-attribute-displayAlign-example-1" role="example">
+<caption>Example Fragment &ndash; Display Align</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;region xml:id="r1"&gt;
+  &lt;style tts:extent="128px 66px" tts:origin="0px 0px"
+       tts:backgroundColor="black" tts:color="white"/&gt;
+  &lt;style <phrase role="strong">tts:displayAlign="before"</phrase>/&gt;
+  &lt;style tts:textAlign="start"/&gt;
+&lt;/region&gt;
+&lt;region xml:id="r2"&gt;
+  &lt;style tts:extent="192px 66px" tts:origin="128px 66px"/&gt;
+       tts:backgroundColor="green" tts:color="white"/&gt;
+  &lt;style <phrase role="strong">tts:displayAlign="after"</phrase>/&gt;
+  &lt;style tts:textAlign="start"/&gt;
+&lt;/region&gt;
+&lt;region xml:id="r3"&gt;
+  &lt;style tts:extent="128px 66px"/&gt; style tts:origin="0px 132px"
+       tts:backgroundColor="black" tts:color="white"/&gt;
+  &lt;style <phrase role="strong">tts:displayAlign="before"</phrase>/&gt;
+  &lt;style tts:textAlign="start"/&gt;
+&lt;/region&gt;
+&lt;region xml:id="r4"&gt;
+  &lt;style tts:extent="192px 66px" tts:origin="128px 198px"/&gt;
+       tts:backgroundColor="green" tts:color="white"/&gt;
+  &lt;style <phrase role="strong">tts:displayAlign="after"</phrase>/&gt;
+  &lt;style tts:textAlign="start"/&gt;
+&lt;/region&gt;
+...
+&lt;div&gt;
+  &lt;p region="r1"&gt;I sent a message to the fish:&lt;/p&gt;
+  &lt;p region="r2"&gt;I told them&lt;br/&gt; "This is what I wish."&lt;/p&gt;
+  &lt;p region="r3"&gt;The little fishes of the sea,&lt;/p&gt;
+  &lt;p region="r4"&gt;They sent an&lt;br/&gt; answer back to me.&lt;/p&gt;
+&lt;/div&gt;
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p></p>
+<table id="style-attribute-displayAlign-example-1-images" role="example-images">
+<caption>Example Rendition &ndash; Display Align</caption>
+<tbody>
+<tr>
+<td><graphic source="images/displayAlign.png" alt="TTML displayAlign style property"/></td>
+</tr>
+</tbody>
+</table>
+<note role="derivation">
+<p>The semantics of the style property
+represented by this attribute are based upon that defined by <bibref ref="xsl11"/>,
+&sect; 7.14.4.</p>
+</note>
+</div3>
+<div3 id="style-attribute-extent">
+<head>tts:extent</head>
+<p>The <att>tts:extent</att> attribute is used to specify the
+<emph>width</emph> and <emph>height</emph> of a region area
+(which may be the <emph>Root Container Region</emph>).</p>
+<p>This attribute may be specified by any
+element type
+that permits use of attributes in the TT Style Namespace; however, this attribute applies
+as a style property only to those element types indicated in the following table.</p>
+<table id="style-property-details-extent" role="common">
+<col width="25%"/>
+<col/>
+<tbody>
+<tr>
+<td><emph>Values:</emph></td>
+<td>
+<code>auto</code> |
+<loc href="#style-value-length">&lt;length&gt;</loc> <loc href="#style-value-length">&lt;length&gt;</loc>
+</td>
+</tr>
+<tr>
+<td><emph>Initial:</emph></td>
+<td><code>auto</code></td>
+</tr>
+<tr>
+<td><emph>Applies to:</emph></td>
+<td>
+<loc href="#document-structure-vocabulary-tt"><el>tt</el></loc>,
+<loc href="#layout-vocabulary-region"><el>region</el></loc>
+</td>
+</tr>
+<tr>
+<td><emph>Inherited:</emph></td>
+<td>no</td>
+</tr>
+<tr>
+<td><emph>Percentages:</emph></td>
+<td>relative to width and height of <emph>Root Container Region</emph></td>
+</tr>
+<tr>
+<td><emph>Animatable:</emph></td>
+<td>discrete</td>
+</tr>
+</tbody>
+</table>
+<p>If the value of this attribute consists of two <loc href="#style-value-length">&lt;length&gt;</loc>
+specifications, then they must be interpreted as <emph>width</emph>
+and <emph>height</emph>, where the first specification is the
+<emph>width</emph>, and the second specification is the <emph>height</emph>.</p>
+<p>The <loc href="#style-value-length">&lt;length&gt;</loc> value(s) used to express extent must be non-negative.</p>
+<p>If the value of this attribute is <code>auto</code>, then the initial value
+of the style property must be considered to be the same as the extent of the <emph>Root Container Region</emph>.</p>
+<p>The extent of the <emph>Root Container Region</emph> is determined either by a
+<att>tts:extent</att> specified on the <el>tt</el> element, if
+present, or as described by <specref ref="document-structure-vocabulary-tt"/> if not present.
+If <att>tts:extent</att> is specified on the <el>tt</el> element, then
+the width and height must be expressed in terms of two <loc href="#style-value-length">&lt;length&gt;</loc> specifications,
+and these specifications must be expressed as non-percentage, definite lengths using pixel units.</p>
+<p>If a specified value of this attribute is not supported,
+then a presentation processor must interpret the attribute as if the
+value <code>auto</code> were specified.</p>
+<p>The <att>tts:extent</att> style is illustrated by the following example.</p>
+<table id="style-attribute-extent-example-1" role="example">
+<caption>Example Fragment &ndash; Extent</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;region xml:id="r1"&gt;
+  &lt;style <phrase role="strong">tts:extent="330px 122px"</phrase>/&gt;
+  &lt;style tts:backgroundColor="black"/&gt;
+  &lt;style tts:color="white"/&gt;
+  &lt;style tts:displayAlign="after"/&gt;
+  &lt;style tts:textAlign="center"/&gt;
+&lt;/region&gt;
+...
+&lt;p region="r1"&gt;
+  'Tis the voice of the Lobster:&lt;br/&gt;
+  I heard him declare,&lt;br/&gt;
+  "You have baked me too brown,&lt;br/&gt;
+  I must sugar my hair."
+&lt;/p&gt;
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p></p>
+<table id="style-attribute-extent-example-1-images" role="example-images">
+<caption>Example Rendition &ndash; Extent</caption>
+<tbody>
+<tr>
+<td><graphic source="images/extent.png" alt="TTML extent style property"/></td>
+</tr>
+</tbody>
+</table>
+</div3>
+<div3 id="style-attribute-fontFamily">
+<head>tts:fontFamily</head>
+<p>The <att>tts:fontFamily</att> attribute is used to specify a style property that
+defines the font family from which glyphs are selected for glyph areas generated
+by content flowed into a region.</p>
+<p>This attribute may be specified by any
+element type
+that permits use of attributes in the TT Style Namespace; however, this attribute applies
+as a style property only to those element types indicated in the following table.</p>
+<table id="style-property-details-fontFamily" role="common">
+<col width="25%"/>
+<col/>
+<tbody>
+<tr>
+<td><emph>Values:</emph></td>
+<td>
+(<loc href="#style-value-familyName">&lt;familyName&gt;</loc> | <loc href="#style-value-genericFamilyName">&lt;genericFamilyName&gt;</loc>)
+(<code>","</code>
+&nbsp;(<loc href="#style-value-familyName">&lt;familyName&gt;</loc> | <loc href="#style-value-genericFamilyName">&lt;genericFamilyName&gt;</loc>))*
+</td>
+</tr>
+<tr>
+<td><emph>Initial:</emph></td>
+<td><code>default</code></td>
+</tr>
+<tr>
+<td><emph>Applies to:</emph></td>
+<td>
+<loc href="#content-vocabulary-span"><el>span</el></loc>
+</td>
+</tr>
+<tr>
+<td><emph>Inherited:</emph></td>
+<td>yes</td>
+</tr>
+<tr>
+<td><emph>Percentages:</emph></td>
+<td>N/A</td>
+</tr>
+<tr>
+<td><emph>Animatable:</emph></td>
+<td>discrete</td>
+</tr>
+</tbody>
+</table>
+<note role="clarification">
+<p>The initial value, <code>default</code>, is a generic font family name, and is
+further described in <specref ref="style-value-genericFamilyName"/> below.</p>
+</note>
+<p>For the purpose of determining applicability of this style property,
+each character child of a <el>p</el> element is considered to be enclosed in an anonymous
+span.</p>
+<p>If a specified font family is not available, then a
+presentation processor must attempt to map the specified font family
+to an available font family that has similar typographic
+characteristics, or, in the absence of such a mapping, it must
+interpret the font family as if the value <code>default</code> were
+specified.</p>
+<p>The <att>tts:fontFamily</att> style is illustrated by the following example.</p>
+<table id="style-attribute-fontFamily-example-1" role="example">
+<caption>Example Fragment &ndash; Font Family</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;region xml:id="r1"&gt;
+  &lt;style tts:extent="474px 146px"/&gt;
+  &lt;style tts:backgroundColor="black"/&gt;
+  &lt;style tts:color="white"/&gt;
+  &lt;style tts:displayAlign="center"/&gt;
+  &lt;style tts:textAlign="start"/&gt;
+  &lt;style <phrase role="strong">tts:fontFamily="proportionalSansSerif"</phrase>/&gt;
+&lt;/region&gt;
+...
+&lt;div region="r1"&gt;
+  &lt;p&gt;
+    "The time has come," the Walrus said,&lt;br/&gt;
+    "to talk of many things:
+  &lt;/p&gt;
+  &lt;p tts:textAlign="end" <phrase role="strong">tts:fontFamily="monospaceSerif"</phrase>&gt;
+    Of shoes, and ships, and sealing wax,&lt;br/&gt;
+    Of cabbages and kings,
+  &lt;/p&gt;
+  &lt;p&gt;
+    And why the sea is boiling hot,&lt;br/&gt;
+    and whether pigs have wings."
+  &lt;/p&gt;
+&lt;/div&gt;
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p></p>
+<table id="style-attribute-fontFamily-example-1-images" role="example-images">
+<caption>Example Rendition &ndash; Font Family</caption>
+<tbody>
+<tr>
+<td><graphic source="images/fontFamily.png" alt="TTML fontFamily style property"/></td>
+</tr>
+</tbody>
+</table>
+<note role="derivation">
+<p>The semantics of the style property
+represented by this attribute are based upon that defined by <bibref ref="xsl11"/>,
+&sect; 7.9.2.</p>
+</note>
+</div3>
+<div3 id="style-attribute-fontSize">
+<head>tts:fontSize</head>
+<p>The <att>tts:fontSize</att> attribute is used to specify a style property
+that defines the font size for glyphs that are selected for glyph areas
+generated by content flowed into a region.</p>
+<p>This attribute may be specified by any element type
+that permits use of attributes in the TT Style Namespace; however, this attribute applies
+as a style property only to those element types indicated in the following table.</p>
+<table id="style-property-details-fontSize" role="common">
+<col width="25%"/>
+<col/>
+<tbody>
+<tr>
+<td><emph>Values:</emph></td>
+<td>
+<loc href="#style-value-length">&lt;length&gt;</loc> <loc href="#style-value-length">&lt;length&gt;</loc>?
+</td>
+</tr>
+<tr>
+<td><emph>Initial:</emph></td>
+<td><code>1c</code></td>
+</tr>
+<tr>
+<td><emph>Applies to:</emph></td>
+<td>
+<loc href="#content-vocabulary-span"><el>span</el></loc>
+</td>
+</tr>
+<tr>
+<td><emph>Inherited:</emph></td>
+<td>yes</td>
+</tr>
+<tr>
+<td><emph>Percentages:</emph></td>
+<td>relative to parent element's font size, or if no parent element, then relative to the <emph>Computed Cell Size</emph></td>
+</tr>
+<tr>
+<td><emph>Animatable:</emph></td>
+<td>discrete</td>
+</tr>
+</tbody>
+</table>
+<p>If a single <loc href="#style-value-length">&lt;length&gt;</loc> value is specified, then this length applies
+equally to horizontal and vertical scaling of a glyph's EM square; if two
+<loc href="#style-value-length">&lt;length&gt;</loc> values are specified, then the first expresses the horizontal
+scaling and the second expresses vertical scaling.</p>
+<note role="example">
+<p>Use of independent horizontal and vertical font sizes is expected to be used
+with cell based units in order to denote fonts that are two rows in height and
+one column in width.</p>
+</note>
+<p>If horizontal and vertical sizes are expressed independently, then the
+units of the <loc href="#style-value-length">&lt;length&gt;</loc> values must be the same.</p>
+<p>The <loc href="#style-value-length">&lt;length&gt;</loc> value(s) used to express font size must be non-negative.</p>
+<p>For the purpose of determining applicability of this style property,
+each character child of a <el>p</el> element is considered to be enclosed in an anonymous
+span.</p>
+<p>If a specified value of this attribute is not supported,
+then a presentation processor must interpret the attribute as if the closest supported value were
+specified.</p>
+<note role="elaboration">
+<p>The expression <code>1c</code> means one cell, where <code>'c'</code> expresses
+the <emph>cell</emph> length unit as defined by <specref ref="style-value-length"/>.
+When a single &lt;length&gt; is expressed using cell units, then it refers to the height of
+the <emph>Computed Cell Size</emph>.</p>
+</note>
+<note role="example">
+<p>As specified above, the use of percentage units to express font size are interpreted as
+relative to <emph>Computed Cell Size</emph> when there is no parent element. For example, if cell resolution
+is 32 by 15, and the extent of the <emph>Root Container Region</emph> is 640 by 480, then the
+<emph>Computed Cell Size</emph> is [20px, 32px], i.e., 640px/32 (width) and 480px/15 (height). Consequently, if
+<att>tts:fontSize</att> were specified as 75% on the root <el>tt</el> element, then this would
+be equivalent to specifying 24px, i.e., 32px cell height * 75%.
+If two length expressions (independent horizontal and vertical font scaling) were specified, e.g.,
+"80% 75%", then this would be equivalent to specifying "16px 24px", i.e., 80% of 20px cell width is
+16px, and 75% of 32px cell height is 24px.</p>
+</note>
+<p>The <att>tts:fontSize</att> style is illustrated by the following example.</p>
+<table id="style-attribute-fontSize-example-1" role="example">
+<caption>Example Fragment &ndash; Font Size</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;region xml:id="r1"&gt;
+  &lt;style tts:extent="299px 97px"/&gt;
+  &lt;style tts:backgroundColor="black"/&gt;
+  &lt;style tts:color="white"/&gt;
+  &lt;style tts:displayAlign="center"/&gt;
+  &lt;style tts:textAlign="center"/&gt;
+  &lt;style tts:fontFamily="proportionalSansSerif"/&gt;
+  &lt;style <phrase role="strong">tts:fontSize="18px"</phrase>/&gt;
+&lt;/region&gt;
+...
+&lt;p region="r1"&gt;
+  Then fill up the glasses&lt;br/&gt;
+  with treacle and ink,&lt;br/&gt;
+  Or anything else&lt;br/&gt;
+  that is &lt;span <phrase role="strong">tts:fontSize="24px"</phrase>&gt;pleasant&lt;/span&gt; to drink.
+&lt;/p&gt;
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p></p>
+<table id="style-attribute-fontSize-example-1-images" role="example-images">
+<caption>Example Rendition &ndash; Font Size</caption>
+<tbody>
+<tr>
+<td><graphic source="images/fontSize.png" alt="TTML fontSize style property"/></td>
+</tr>
+</tbody>
+</table>
+<note role="derivation">
+<p>The semantics of the style property
+represented by this attribute are based upon that defined by <bibref ref="xsl11"/>,
+&sect; 7.9.4. The addition of a second length component to permit specifying font
+width and height independently is an extension introduced by TTML.</p>
+</note>
+</div3>
+<div3 id="style-attribute-fontStyle">
+<head>tts:fontStyle</head>
+<p>The <att>tts:fontStyle</att> attribute is used to specify a style property that
+defines the font style to apply to glyphs that are selected for glyph areas generated
+by content flowed into a region, where the mapping from font
+style value to specific font face or style parameterization is not determined
+by this specification.</p>
+<p>This attribute may be specified by any
+element type
+that permits use of attributes in the TT Style Namespace; however, this attribute applies
+as a style property only to those element types indicated in the following table.</p>
+<table id="style-property-details-fontStyle" role="common">
+<col width="25%"/>
+<col/>
+<tbody>
+<tr>
+<td><emph>Values:</emph></td>
+<td>
+<code>normal</code> |
+<code>italic</code> |
+<code>oblique</code>
+</td>
+</tr>
+<tr>
+<td><emph>Initial:</emph></td>
+<td><code>normal</code></td>
+</tr>
+<tr>
+<td><emph>Applies to:</emph></td>
+<td>
+<loc href="#content-vocabulary-span"><el>span</el></loc>
+</td>
+</tr>
+<tr>
+<td><emph>Inherited:</emph></td>
+<td>yes</td>
+</tr>
+<tr>
+<td><emph>Percentages:</emph></td>
+<td>N/A</td>
+</tr>
+<tr>
+<td><emph>Animatable:</emph></td>
+<td>discrete</td>
+</tr>
+</tbody>
+</table>
+<p>For the purpose of determining applicability of this style property,
+each character child of a <el>p</el> element is considered to be enclosed in an anonymous
+span.</p>
+<p>Use of the value <code>oblique</code>
+denotes a shear transformation (at an unspecified
+angle) in the inline progression dimension.</p>
+<p>If a specified font style is not available, then a
+presentation processor must attempt to map the specified font style
+to an available font style that has similar typographic
+characteristics, or, in the absence of such a mapping, it must
+interpret the font style as if the value <code>normal</code> were
+specified.</p>
+<p>The <att>tts:fontStyle</att> style is illustrated by the following example.</p>
+<table id="style-attribute-fontStyle-example-1" role="example">
+<caption>Example Fragment &ndash; Font Style</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;region xml:id="r1"&gt;
+  &lt;style tts:extent="331px 84px"/&gt;
+  &lt;style tts:backgroundColor="black"/&gt;
+  &lt;style tts:color="white"/&gt;
+  &lt;style tts:displayAlign="after"/&gt;
+  &lt;style tts:textAlign="center"/&gt;
+  &lt;style tts:fontFamily="proportionalSansSerif"/&gt;
+&lt;/region&gt;
+...
+&lt;p region="r1"&gt;
+  In autumn, when the leaves are brown,&lt;br/&gt;
+  Take pen and ink, and &lt;span <phrase role="strong">tts:fontStyle="italic"</phrase>&gt;write it down.&lt;/span&gt;
+&lt;/p&gt;
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p></p>
+<table id="style-attribute-fontStyle-example-1-images" role="example-images">
+<caption>Example Rendition &ndash; Font Style</caption>
+<tbody>
+<tr>
+<td><graphic source="images/fontStyle.png" alt="TTML fontStyle style property"/></td>
+</tr>
+</tbody>
+</table>
+<p></p>
+<note role="derivation">
+<p>The semantics of the style property
+represented by this attribute are based upon that defined by <bibref ref="xsl11"/>,
+&sect; 7.9.7.</p>
+</note>
+</div3>
+<div3 id="style-attribute-fontWeight">
+<head>tts:fontWeight</head>
+<p>The <att>tts:fontWeight</att> attribute is used to specify a style property
+that defines the font weight to apply to glyphs that are selected for glyph
+areas generated by content flowed into a region, where the mapping from font
+weight value to specific font face or weight parameterization is not determined
+by this specification.</p>
+<p>This attribute may be specified by any
+element type
+that permits use of attributes in the TT Style Namespace; however, this attribute applies
+as a style property only to those element types indicated in the following table.</p>
+<table id="style-property-details-fontWeight" role="common">
+<col width="25%"/>
+<col/>
+<tbody>
+<tr>
+<td><emph>Values:</emph></td>
+<td>
+<code>normal</code> |
+<code>bold</code>
+</td>
+</tr>
+<tr>
+<td><emph>Initial:</emph></td>
+<td><code>normal</code></td>
+</tr>
+<tr>
+<td><emph>Applies to:</emph></td>
+<td>
+<loc href="#content-vocabulary-span"><el>span</el></loc>
+</td>
+</tr>
+<tr>
+<td><emph>Inherited:</emph></td>
+<td>yes</td>
+</tr>
+<tr>
+<td><emph>Percentages:</emph></td>
+<td>N/A</td>
+</tr>
+<tr>
+<td><emph>Animatable:</emph></td>
+<td>discrete</td>
+</tr>
+</tbody>
+</table>
+<p>For the purpose of determining applicability of this style property,
+each character child of a <el>p</el> element is considered to be enclosed in an anonymous
+span.</p>
+<p>If a specified font weight is not available, then a
+presentation processor must attempt to map the specified font weight
+to an available font weight that has similar typographic
+characteristics, or, in the absence of such a mapping, it must
+interpret the font weight as if the value <code>normal</code> were
+specified.</p>
+<p>The <att>tts:fontWeight</att> style is illustrated by the following example.</p>
+<table id="style-attribute-fontWeight-example-1" role="example">
+<caption>Example Fragment &ndash; Font Weight</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;region xml:id="r1"&gt;
+  &lt;style tts:extent="376px 95px"/&gt;
+  &lt;style tts:backgroundColor="black"/&gt;
+  &lt;style tts:color="white"/&gt;
+  &lt;style tts:displayAlign="center"/&gt;
+  &lt;style tts:textAlign="center"/&gt;
+  &lt;style tts:fontFamily="proportionalSansSerif"/&gt;
+&lt;/region&gt;
+...
+&lt;p region="r1"&gt;
+  They told me you had been to her,&lt;br/&gt;
+  &lt;span <phrase role="strong">tts:fontWeight="bold"</phrase>&gt;and mentioned me to him:&lt;/span&gt;&lt;br/&gt;
+  She gave me a good character&lt;br/&gt;
+  &lt;span <phrase role="strong">tts:fontWeight="bold"</phrase>&gt;but said I could not swim.&lt;/span&gt;
+&lt;/p&gt;
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p></p>
+<table id="style-attribute-fontWeight-example-1-images" role="example-images">
+<caption>Example Rendition &ndash; Font Weight</caption>
+<tbody>
+<tr>
+<td><graphic source="images/fontWeight.png" alt="TTML fontWeight style property"/></td>
+</tr>
+</tbody>
+</table>
+<note role="derivation">
+<p>The semantics of the style property
+represented by this attribute are based upon that defined by <bibref ref="xsl11"/>,
+&sect; 7.9.9.</p>
+</note>
+</div3>
+<div3 id="style-attribute-lineHeight">
+<head>tts:lineHeight</head>
+<p>The <att>tts:lineHeight</att> attribute is used to specify a style property that
+defines the inter-baseline separation between line areas generated by content flowed into a region.</p>
+<p>This attribute may be specified by any
+element type
+that permits use of attributes in the TT Style Namespace; however, this attribute applies
+as a style property only to those element types indicated in the following table.</p>
+<table id="style-property-details-lineHeight" role="common">
+<col width="25%"/>
+<col/>
+<tbody>
+<tr>
+<td><emph>Values:</emph></td>
+<td>
+<code>normal</code> |
+<loc href="#style-value-length">&lt;length&gt;</loc>
+</td>
+</tr>
+<tr>
+<td><emph>Initial:</emph></td>
+<td><code>normal</code></td>
+</tr>
+<tr>
+<td><emph>Applies to:</emph></td>
+<td>
+<loc href="#content-vocabulary-p"><el>p</el></loc>
+</td>
+</tr>
+<tr>
+<td><emph>Inherited:</emph></td>
+<td>yes</td>
+</tr>
+<tr>
+<td><emph>Percentages:</emph></td>
+<td>relative to this element's font size</td>
+</tr>
+<tr>
+<td><emph>Animatable:</emph></td>
+<td>discrete</td>
+</tr>
+</tbody>
+</table>
+<p>If the value of this attribute is <code>normal</code>, then the
+initial value of the style property must be considered to be the same
+as the largest font size that applies to any
+descendant element.</p>
+<p>If specified as a <loc
+href="#style-value-length">&lt;length&gt;</loc>, then the length must
+be non-negative.</p>
+<p>If a specified value of this attribute is not supported,
+then a presentation processor must interpret the attribute as if the
+value <code>normal</code> were specified.</p>
+<p>The <att>tts:lineHeight</att> style is illustrated by the following example.</p>
+<table id="style-attribute-lineHeight-example-1" role="example">
+<caption>Example Fragment &ndash; Line Height</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;region xml:id="r1"&gt;
+  &lt;style tts:extent="255px 190px"/&gt;
+  &lt;style tts:backgroundColor="black"/&gt;
+  &lt;style tts:color="white"/&gt;
+  &lt;style tts:displayAlign="center"/&gt;
+  &lt;style tts:textAlign="start"/&gt;
+  &lt;style tts:fontFamily="proportionalSansSerif"/&gt;
+  &lt;style tts:fontSize="16px"/&gt;
+  &lt;style <phrase role="strong">tts:lineHeight="32px"</phrase>/&gt;
+&lt;/region&gt;
+...
+&lt;p region="r1"&gt;
+  He thought he saw an elephant,&lt;br/&gt;
+  That practised on a fife:&lt;br/&gt;
+  He looked again, and found it was&lt;br/&gt;
+  A letter from his wife.&lt;br/&gt;
+  "At length I realise," he said,&lt;br/&gt;
+  "The bitterness of Life.
+"&lt;/p&gt;
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p></p>
+<table id="style-attribute-lineHeight-example-1-images" role="example-images">
+<caption>Example Rendition &ndash; Line Height</caption>
+<tbody>
+<tr>
+<td><graphic source="images/lineHeight.png" alt="TTML lineHeight style property"/></td>
+</tr>
+</tbody>
+</table>
+<p></p>
+<note role="derivation">
+<p>The semantics of the style property
+represented by this attribute are based upon that defined by <bibref ref="xsl11"/>,
+&sect; 7.16.4. Furthermore, it is the intention of this specification that the
+allocation rectangle of a line be consistent with the <phrase role="strong">per-inline-height-rectangle</phrase>
+as defined by <bibref ref="xsl11"/>, &sect; 4.5, i.e., that a CSS-style line box stacking strategy be used.
+</p>
+</note>
+</div3>
+<div3 id="style-attribute-opacity">
+<head>tts:opacity</head>
+<p>The <att>tts:opacity</att> attribute is used to specify a style property that
+defines the opacity (or conversely, the transparency)
+of marks associated with a region.</p>
+<p>When presented onto a visual medium, the opacity of the region is applied uniformly and on a linear scale
+to all marks produced by content targeted to the
+region.</p>
+<p>This attribute may be specified by any
+element type
+that permits use of attributes in the TT Style Namespace; however, this attribute applies
+as a style property only to those element types indicated in the following table.</p>
+<table id="style-property-details-opacity" role="common">
+<col width="25%"/>
+<col/>
+<tbody>
+<tr>
+<td><emph>Values:</emph></td>
+<td>
+<loc href="#style-value-alpha">&lt;alpha&gt;</loc>
+</td>
+</tr>
+<tr>
+<td><emph>Initial:</emph></td>
+<td>
+<code>1.0</code>
+</td>
+</tr>
+<tr>
+<td><emph>Applies to:</emph></td>
+<td>
+<loc href="#layout-vocabulary-region"><el>region</el></loc>
+</td>
+</tr>
+<tr>
+<td><emph>Inherited:</emph></td>
+<td>no</td>
+</tr>
+<tr>
+<td><emph>Percentages:</emph></td>
+<td>N/A</td>
+</tr>
+<tr>
+<td><emph>Animatable:</emph></td>
+<td>discrete</td>
+</tr>
+</tbody>
+</table>
+<p>The <att>tts:opacity</att> style is illustrated by the following example.</p>
+<table id="style-attribute-opacity-example-1" role="example">
+<caption>Example Fragment &ndash; Opacity</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;region xml:id="r1" dur="5s"&gt;
+  &lt;set begin="0s" dur="1s" <phrase role="strong">tts:opacity="1.00"</phrase>/&gt;
+  &lt;set begin="1s" dur="1s" <phrase role="strong">tts:opacity="0.75"</phrase>/&gt;
+  &lt;set begin="2s" dur="1s" <phrase role="strong">tts:opacity="0.50"</phrase>/&gt;
+  &lt;set begin="3s" dur="1s" <phrase role="strong">tts:opacity="0.25"</phrase>/&gt;
+  &lt;set begin="4s" dur="1s" <phrase role="strong">tts:opacity="0.00"</phrase>/&gt;
+  &lt;style tts:extent="304px 77px"/&gt;
+  &lt;style tts:backgroundColor="black"/&gt;
+  &lt;style tts:color="white"/&gt;
+  &lt;style tts:displayAlign="after"/&gt;
+  &lt;style tts:textAlign="center"/&gt;
+&lt;/region&gt;
+...
+&lt;p region="r1"&gt;
+  The sun was shining on the sea
+&lt;/p&gt;
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p></p>
+<table id="style-attribute-opacity-example-1-images" role="example-images">
+<caption>Example Rendition &ndash; Opacity</caption>
+<tbody>
+<tr>
+<td>
+<graphic source="images/opacity_0.png" alt="TTML opacity style property - [0,1)"/>
+</td>
+</tr>
+<tr>
+<td>
+<graphic source="images/opacity_1.png" alt="TTML opacity style property - [1,2)"/>
+</td>
+</tr>
+<tr>
+<td>
+<graphic source="images/opacity_2.png" alt="TTML opacity style property - [2,3)"/>
+</td>
+</tr>
+<tr>
+<td>
+<graphic source="images/opacity_3.png" alt="TTML opacity style property - [3,4)"/>
+</td>
+</tr>
+<tr>
+<td>
+<graphic source="images/opacity_4.png" alt="TTML opacity style property - [4,5)"/>
+</td>
+</tr>
+</tbody>
+</table>
+<note role="derivation">
+<p>The semantics of the style property
+represented by this attribute are based upon that defined by <bibref ref="css3-color"/>,
+&sect; 3.2.</p>
+</note>
+</div3>
+<div3 id="style-attribute-origin">
+<head>tts:origin</head>
+<p>The <att>tts:origin</att> attribute is used to specify the
+<emph>x</emph> and <emph>y</emph> coordinates of the origin of a
+region area with respect to the origin of the <emph>Root Container Region</emph>.</p>
+<p>This attribute may be specified by any
+element type
+that permits use of attributes in the TT Style Namespace; however, this attribute applies
+as a style property only to those element types indicated in the following table.</p>
+<table id="style-property-details-origin" role="common">
+<col width="25%"/>
+<col/>
+<tbody>
+<tr>
+<td><emph>Values:</emph></td>
+<td>
+<code>auto</code> |
+<loc href="#style-value-length">&lt;length&gt;</loc> <loc href="#style-value-length">&lt;length&gt;</loc>
+</td>
+</tr>
+<tr>
+<td><emph>Initial:</emph></td>
+<td><code>auto</code></td>
+</tr>
+<tr>
+<td><emph>Applies to:</emph></td>
+<td>
+<loc href="#layout-vocabulary-region"><el>region</el></loc>
+</td>
+</tr>
+<tr>
+<td><emph>Inherited:</emph></td>
+<td>no</td>
+</tr>
+<tr>
+<td><emph>Percentages:</emph></td>
+<td>relative to width and height of <emph>Root Container Region</emph></td>
+</tr>
+<tr>
+<td><emph>Animatable:</emph></td>
+<td>discrete</td>
+</tr>
+</tbody>
+</table>
+<p>If the value of this attribute consists of two <loc href="#style-value-length">&lt;length&gt;</loc> specifications,
+then they must be interpreted as <emph>x</emph> and <emph>y</emph> coordinates, where the first specification
+is the <emph>x</emph> coordinate, and the second specification is the <emph>y</emph> coordinate.</p>
+<p>If the value of this attribute is <code>auto</code>, then the initial value
+of the style property must be considered to be the same as the origin of the <emph>Root Container Region</emph>.</p>
+<p>If a specified value of this attribute is not supported,
+then a presentation processor must interpret the attribute as if the
+value <code>auto</code> were specified.</p>
+<p>The <att>tts:origin</att> style is illustrated by the following example.</p>
+<table id="style-attribute-origin-example-1" role="example">
+<caption>Example Fragment &ndash; Origin</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;region xml:id="r1"&gt;
+  &lt;style <phrase role="strong">tts:origin="40px 40px"</phrase>/&gt;
+  &lt;style tts:extent="308px 92px"/&gt;
+  &lt;style tts:backgroundColor="black"/&gt;
+  &lt;style tts:color="white"/&gt;
+  &lt;style tts:displayAlign="center"/&gt;
+  &lt;style tts:textAlign="center"/&gt;
+&lt;/region&gt;
+...
+&lt;p region="r1"&gt;
+  "To dine!" she shrieked in dragon-wrath.&lt;br/&gt;
+  "To swallow wines all foam and froth!&lt;br/&gt;
+   To simper at a table-cloth!"
+&lt;/p&gt;
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p></p>
+<table id="style-attribute-origin-example-1-images" role="example-images">
+<caption>Example Rendition &ndash; Origin</caption>
+<tbody>
+<tr>
+<td><graphic source="images/origin.png" alt="TTML origin style property"/></td>
+</tr>
+</tbody>
+</table>
+</div3>
+<div3 id="style-attribute-overflow">
+<head>tts:overflow</head>
+<p>The <att>tts:overflow</att> attribute is used to specify a style property that
+defines whether a region area is clipped or not if the descendant areas of the region overflow
+its extent.</p>
+<p>This attribute may be specified by any
+element type
+that permits use of attributes in the TT Style Namespace; however, this attribute applies
+as a style property only to those element types indicated in the following table.</p>
+<table id="style-property-details-overflow" role="common">
+<col width="25%"/>
+<col/>
+<tbody>
+<tr>
+<td><emph>Values:</emph></td>
+<td>
+<code>visible</code> |
+<code>hidden</code>
+</td>
+</tr>
+<tr>
+<td><emph>Initial:</emph></td>
+<td><code>hidden</code></td>
+</tr>
+<tr>
+<td><emph>Applies to:</emph></td>
+<td>
+<loc href="#layout-vocabulary-region"><el>region</el></loc>
+</td>
+</tr>
+<tr>
+<td><emph>Inherited:</emph></td>
+<td>no</td>
+</tr>
+<tr>
+<td><emph>Percentages:</emph></td>
+<td>N/A</td>
+</tr>
+<tr>
+<td><emph>Animatable:</emph></td>
+<td>discrete</td>
+</tr>
+</tbody>
+</table>
+<p>If the value of this attribute is <code>visible</code>, then content should
+not be clipped outside of the affected region, and region composition and layout
+must be performed as if the region's width and height were
+unconstrained,
+but with
+a well-defined origin.  If the value is <code>hidden</code>, then content should
+be clipped outside of the affected region.</p>
+<note role="explanation">
+<p>Unless a manual line break element <el>br</el> is used by the content author,
+a paragraph of a given region will generate no more than one line area in that
+region if the value of the <att>tts:overflow</att> style that applies to the
+region is <code>visible</code> and if the applicable <att>tts:wrapOption</att>
+style is <code>noWrap</code>.</p>
+</note>
+<p>If a specified value of this attribute is not supported,
+then a presentation processor must interpret the attribute as if the
+value <code>hidden</code> were specified.</p>
+<p>The <att>tts:overflow</att> style is illustrated by the following example.</p>
+<table id="style-attribute-overflow-example-1" role="example">
+<caption>Example Fragment &ndash; Overflow</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;region xml:id="r1"&gt;
+  &lt;style tts:extent="232px 40px"/&gt;
+  &lt;style tts:origin="0px 0px"/&gt;
+  &lt;style tts:backgroundColor="black"/&gt;
+  &lt;style tts:color="red"/&gt;
+  &lt;style tts:displayAlign="before"/&gt;
+  &lt;style tts:textAlign="start"/&gt;
+  &lt;style tts:fontFamily="proportionalSansSerif"/&gt;
+  &lt;style tts:fontSize="18px"/&gt;
+  &lt;style tts:wrapOption="noWrap"/&gt;
+  &lt;style <phrase role="strong">tts:overflow="visible"</phrase>/&gt;
+&lt;/region&gt;
+&lt;region xml:id="r2"&gt;
+  &lt;style tts:extent="232px 40px"/&gt;
+  &lt;style tts:origin="0px 43px"/&gt;
+  &lt;style tts:backgroundColor="black"/&gt;
+  &lt;style tts:color="red"/&gt;
+  &lt;style tts:displayAlign="before"/&gt;
+  &lt;style tts:textAlign="start"/&gt;
+  &lt;style tts:fontFamily="proportionalSansSerif"/&gt;
+  &lt;style tts:fontSize="18px"/&gt;
+  &lt;style tts:wrapOption="noWrap"/&gt;
+  &lt;style <phrase role="strong">tts:overflow="hidden"</phrase>/&gt;
+&lt;/region&gt;
+...
+&lt;p region="r1"&gt;
+  "But wait a bit," the Oysters cried,&lt;br/&gt;
+  "Before we have our chat;
+&lt;/p&gt;
+&lt;p region="r2"&gt;
+  For some of us are out of breath,&lt;br/&gt;
+  And all of us are fat!"
+&lt;/p&gt;
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p></p>
+<table id="style-attribute-overflow-example-1-images" role="example-images">
+<caption>Example Rendition &ndash; Overflow</caption>
+<tbody>
+<tr>
+<td><graphic source="images/overflow.png" alt="TTML overflow style property"/></td>
+</tr>
+</tbody>
+</table>
+<note role="explanation">
+<p>In the above example, the <att>tts:noWrap</att> is set to
+<code>noWrap</code> to prevent automatic line wrapping (breaking);
+if this were not specified, then overflow would occur in the block
+progression direction as opposed to the inline progression direction.</p>
+</note>
+<note role="derivation">
+<p>The semantics of the style property
+represented by this attribute are based upon that defined by <bibref ref="xsl11"/>,
+&sect; 7.21.2.</p>
+</note>
+</div3>
+<div3 id="style-attribute-padding">
+<head>tts:padding</head>
+<p>The <att>tts:padding</att> attribute is used to specify padding (or inset)
+space on all sides of a region area.</p>
+<p>This attribute may be specified by any
+element type
+that permits use of attributes in the TT Style Namespace; however, this attribute applies
+as a style property only to those element types indicated in the following table.</p>
+<table id="style-property-details-padding" role="common">
+<col width="25%"/>
+<col/>
+<tbody>
+<tr>
+<td><emph>Values:</emph></td>
+<td>
+<loc href="#style-value-length">&lt;length&gt;</loc> |
+<loc href="#style-value-length">&lt;length&gt;</loc> <loc href="#style-value-length">&lt;length&gt;</loc> |
+<loc href="#style-value-length">&lt;length&gt;</loc> <loc href="#style-value-length">&lt;length&gt;</loc> <loc href="#style-value-length">&lt;length&gt;</loc> |
+<loc href="#style-value-length">&lt;length&gt;</loc> <loc href="#style-value-length">&lt;length&gt;</loc> <loc href="#style-value-length">&lt;length&gt;</loc> <loc href="#style-value-length">&lt;length&gt;</loc>
+</td>
+</tr>
+<tr>
+<td><emph>Initial:</emph></td>
+<td><code>0px</code></td>
+</tr>
+<tr>
+<td><emph>Applies to:</emph></td>
+<td>
+<loc href="#layout-vocabulary-region"><el>region</el></loc>
+</td>
+</tr>
+<tr>
+<td><emph>Inherited:</emph></td>
+<td>no</td>
+</tr>
+<tr>
+<td><emph>Percentages:</emph></td>
+<td>relative to width and height of region</td>
+</tr>
+<tr>
+<td><emph>Animatable:</emph></td>
+<td>discrete</td>
+</tr>
+</tbody>
+</table>
+<p>If the value of this attribute consists of one <loc href="#style-value-length">&lt;length&gt;</loc> specification,
+then that length applies to all edges of the affected areas. If the value
+consists of two <loc href="#style-value-length">&lt;length&gt;</loc> specifications, then the first applies to the
+before and after edges, and the second applies to the start and end edges.
+If three <loc href="#style-value-length">&lt;length&gt;</loc> specifications are provided, then the first applies to the
+before edge, the second applies to the start and end edges, and the third applies
+to the after edge.
+If four <loc href="#style-value-length">&lt;length&gt;</loc> specifications are provided, then they apply to before, end,
+after, and start edges, respectively.</p>
+<p>The <loc href="#style-value-length">&lt;length&gt;</loc> value(s) used to express padding must be non-negative.</p>
+<p>If a specified value of this attribute is not supported,
+then a presentation processor must interpret the attribute as if the
+value <code>0px</code> were specified.</p>
+<p>The <att>tts:padding</att> style is illustrated by the following example.</p>
+<table id="style-attribute-padding-example-1" role="example">
+<caption>Example Fragment &ndash; Padding</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;region xml:id="r1"&gt;
+  &lt;style tts:extent="446px 104px"/&gt;
+  &lt;style tts:backgroundColor="black"/&gt;
+  &lt;style tts:color="white"/&gt;
+  &lt;style tts:displayAlign="after"/&gt;
+  &lt;style tts:textAlign="center"/&gt;
+  &lt;style <phrase role="strong">tts:padding="10px 40px"</phrase>/&gt;
+&lt;/region&gt;
+...
+&lt;p region="r1" tts:backgroundColor="red"&gt;
+  Just the place for a Snark! I have said it twice:&lt;br/&gt;
+  That alone should encourage the crew.&lt;br/&gt;
+  Just the place for a Snark! I have said it thrice:&lt;br/&gt;
+  What I tell you three times is true.
+&lt;/p&gt;
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p>When rendering an area to which padding applies, the background color that
+applies to the area is rendered into the padded portion of the area.</p>
+<table id="style-attribute-padding-example-1-images" role="example-images">
+<caption>Example Rendition &ndash; Padding</caption>
+<tbody>
+<tr>
+<td>
+<graphic source="images/padding.png" alt="TTML padding style property"/>
+</td>
+</tr>
+</tbody>
+</table>
+<note role="derivation">
+<p>The semantics of the style property
+represented by this attribute are based upon that defined by <bibref ref="xsl11"/>,
+&sect; 7.31.15, except that individual shorthand values map to writing
+mode relative padding values as defined by <bibref ref="xsl11"/>,
+&sect; 7.8.31, 7.8.32, 7.8.33, and 7.8.34.</p>
+</note>
+</div3>
+<div3 id="style-attribute-showBackground">
+<head>tts:showBackground</head>
+<p>The <att>tts:showBackground</att> attribute is used to specify
+constraints on when the background color of a region is intended to be
+presented.</p>
+<p>This attribute may be specified by any
+element type
+that permits use of attributes in the TT Style Namespace; however, this attribute applies
+as a style property only to those element types indicated in the following table.</p>
+<table id="style-property-details-showBackground" role="common">
+<col width="25%"/>
+<col/>
+<tbody>
+<tr>
+<td><emph>Values:</emph></td>
+<td>
+<code>always</code> |
+<code>whenActive</code>
+</td>
+</tr>
+<tr>
+<td><emph>Initial:</emph></td>
+<td><code>always</code></td>
+</tr>
+<tr>
+<td><emph>Applies to:</emph></td>
+<td>
+<loc href="#layout-vocabulary-region"><el>region</el></loc>
+</td>
+</tr>
+<tr>
+<td><emph>Inherited:</emph></td>
+<td>no</td>
+</tr>
+<tr>
+<td><emph>Percentages:</emph></td>
+<td>N/A</td>
+</tr>
+<tr>
+<td><emph>Animatable:</emph></td>
+<td>discrete</td>
+</tr>
+</tbody>
+</table>
+<p>If the value of this attribute is <code>always</code>, then the
+background color of a region is always rendered when performing presentation
+processing on a visual medium; if the value is <code>whenActive</code>,
+then the background color of a region is rendered only when some
+content is flowed into the region.</p>
+<p>If a specified value of this attribute is not supported,
+then a presentation processor must interpret the attribute as if the
+value <code>always</code> were specified.</p>
+<p>The <att>tts:showBackground</att> style is illustrated by the following example.</p>
+<table id="style-attribute-showBackground-example-1" role="example">
+<caption>Example Fragment &ndash; Show Background</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;region xml:id="r1"&gt;
+  &lt;style tts:origin="0px 0px"/&gt;
+  &lt;style tts:extent="265px 100px"/&gt;
+  &lt;style tts:backgroundColor="black"/&gt;
+  &lt;style <phrase role="strong">tts:showBackground="always"</phrase>/&gt;
+  &lt;style tts:color="white"/&gt;
+  &lt;style tts:displayAlign="before"/&gt;
+  &lt;style tts:textAlign="start"/&gt;
+&lt;/region&gt;
+&lt;region xml:id="r2"&gt;
+  &lt;style tts:origin="205px 60px"/&gt;
+  &lt;style tts:extent="290px 100px"/&gt;
+  &lt;style tts:backgroundColor="red"/&gt;
+  &lt;style tts:color="white"/&gt;
+  &lt;style tts:displayAlign="before"/&gt;
+  &lt;style tts:textAlign="end"/&gt;
+  &lt;style <phrase role="strong">tts:showBackground="whenActive"</phrase>/&gt;
+&lt;/region&gt;
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<note role="derivation">
+<p>The semantics of the style property
+represented by this attribute are based upon that defined by <bibref ref="smil21"/>,
+&sect; 5.3.3.</p>
+</note>
+</div3>
+<div3 id="style-attribute-textAlign">
+<head>tts:textAlign</head>
+<p>The <att>tts:textAlign</att> attribute is used to specify a style property that
+defines how inline areas are aligned within a containing block area in the inline progression
+direction.</p>
+<p>This attribute may be specified by any
+element type
+that permits use of attributes in the TT Style Namespace; however, this attribute applies
+as a style property only to those element types indicated in the following table.</p>
+<table id="style-property-details-textAlign" role="common">
+<col width="25%"/>
+<col/>
+<tbody>
+<tr>
+<td><emph>Values:</emph></td>
+<td>
+<code>left</code> |
+<code>center</code> |
+<code>right</code> |
+<code>start</code> |
+<code>end</code>
+</td>
+</tr>
+<tr>
+<td><emph>Initial:</emph></td>
+<td><code>start</code></td>
+</tr>
+<tr>
+<td><emph>Applies to:</emph></td>
+<td>
+<loc href="#content-vocabulary-p"><el>p</el></loc>
+</td>
+</tr>
+<tr>
+<td><emph>Inherited:</emph></td>
+<td>yes</td>
+</tr>
+<tr>
+<td><emph>Percentages:</emph></td>
+<td>N/A</td>
+</tr>
+<tr>
+<td><emph>Animatable:</emph></td>
+<td>discrete</td>
+</tr>
+</tbody>
+</table>
+<p>If a specified value of this attribute is not supported,
+then a presentation processor must interpret the attribute as if the
+value <code>start</code> were specified.</p>
+<p>The <att>tts:textAlign</att> style is illustrated by the following example.</p>
+<table id="style-attribute-textAlign-example-1" role="example">
+<caption>Example Fragment &ndash; Text Align</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;region xml:id="r1"&gt;
+  &lt;style tts:extent="355px 43px"/&gt;
+  &lt;style tts:origin="0px 0px"/&gt;
+  &lt;style tts:backgroundColor="black"/&gt;
+  &lt;style tts:color="white"/&gt;
+  &lt;style <phrase role="strong">tts:textAlign="start"</phrase>/&gt;
+&lt;/region&gt;
+&lt;region xml:id="r2"&gt;
+  &lt;style tts:extent="355px 43px"/&gt;
+  &lt;style tts:origin="0px 47px"/&gt;
+  &lt;style tts:backgroundColor="black"/&gt;
+  &lt;style tts:color="white"/&gt;
+  &lt;style <phrase role="strong">tts:textAlign="end"</phrase>/&gt;
+&lt;/region&gt;
+...
+&lt;p region="r1"&gt;
+  Beware the Jabberwock, my son!&lt;br/&gt;
+  The jaws that bite, the claws that catch!
+&lt;/p&gt;
+&lt;p region="r2"&gt;
+  Beware the Jubjub bird, and shun&lt;br/&gt;
+  The frumious Bandersnatch!
+&lt;/p&gt;
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p></p>
+<table id="style-attribute-textAlign-example-1-images" role="example-images">
+<caption>Example Rendition &ndash; Text Align</caption>
+<tbody>
+<tr>
+<td><graphic source="images/textAlign.png" alt="TTML textAlign style property"/></td>
+</tr>
+</tbody>
+</table>
+<note role="derivation">
+<p>The semantics of the style property
+represented by this attribute are based upon that defined by <bibref ref="xsl11"/>,
+&sect; 7.16.9.</p>
+</note>
+</div3>
+<div3 id="style-attribute-textDecoration">
+<head>tts:textDecoration</head>
+<p>The <att>tts:textDecoration</att> attribute is used to specify a style property that
+defines a text decoration effect to apply to glyph areas or other inline
+areas that are generated by content flowed into a region.</p>
+<p>This attribute may be specified by any
+element type
+that permits use of attributes in the TT Style Namespace; however, this attribute applies
+as a style property only to those element types indicated in the following table.</p>
+<table id="style-property-details-textDecoration" role="common">
+<col width="25%"/>
+<col/>
+<tbody>
+<tr>
+<td><emph>Values:</emph></td>
+<td>
+<code>none</code> |
+[ [
+<code>underline</code> |
+<code>noUnderline</code>
+] || [
+<code>lineThrough</code> |
+<code>noLineThrough</code>
+] || [
+<code>overline</code> |
+<code>noOverline</code>
+] ]
+</td>
+</tr>
+<tr>
+<td><emph>Initial:</emph></td>
+<td><code>none</code></td>
+</tr>
+<tr>
+<td><emph>Applies to:</emph></td>
+<td><loc
+href="#content-vocabulary-span"><el>span</el></loc></td>
+</tr>
+<tr>
+<td><emph>Inherited:</emph></td>
+<td>yes</td>
+</tr>
+<tr>
+<td><emph>Percentages:</emph></td>
+<td>N/A</td>
+</tr>
+<tr>
+<td><emph>Animatable:</emph></td>
+<td>discrete</td>
+</tr>
+</tbody>
+</table>
+<p>For the purpose of determining applicability of this
+style property, each character child of a <el>p</el> element is
+considered to be enclosed in an anonymous span.</p>
+<p>If a specified value of this attribute is not supported,
+then a presentation processor must interpret the attribute as if the
+value <code>none</code> were specified.</p>
+
+<note role="clarification">
+<p>The syntax used above in defining the value of this property is based on the
+value component syntax defined in <bibref ref="css2"/>, &sect; 1.4.2.1. In essence,
+one or more of the values separated by <code>||</code> may appear in the property
+value in any order, such as <code>"noUnderline overline lineThrough"</code>.</p>
+</note>
+
+<p>The <att>tts:textDecoration</att> style is illustrated by the following example.</p>
+<table id="style-attribute-textDecoration-example-1" role="example">
+<caption>Example Fragment &ndash; Text Decoration</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;region xml:id="r1"&gt;
+  &lt;style tts:extent="385px 82px"/&gt;
+  &lt;style tts:origin="0px 0px"/&gt;
+  &lt;style tts:backgroundColor="black"/&gt;
+  &lt;style tts:color="white"/&gt;
+  &lt;style tts:padding="5px 2px"/&gt;
+  &lt;style <phrase role="strong">tts:textDecoration="underline"</phrase>/&gt;
+&lt;/region&gt;
+...
+&lt;p region="r1"&gt;
+  The sea was wet&lt;span <phrase role="strong">tts:textDecoration="noUnderline"</phrase>&gt; as &lt;/span&gt;wet
+  &lt;span <phrase role="strong">tts:textDecoration="noUnderline"</phrase>&gt;
+    could be,&lt;br/&gt;
+    The sand was dry as dry.&lt;br/&gt;
+    &lt;span <phrase role="strong">tts:textDecoration="lineThrough"</phrase>&gt;There weren't any&lt;/span&gt;
+    You &lt;span <phrase role="strong">tts:textDecoration="lineThrough"</phrase>&gt;couldn't&lt;/span&gt;
+    could not see a cloud&lt;br/&gt;
+    Because no cloud was in the sky.
+  &lt;/span&gt;
+&lt;/p&gt;
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p></p>
+<table id="style-attribute-textDecoration-example-1-images" role="example-images">
+<caption>Example Rendition &ndash; Text Decoration</caption>
+<tbody>
+<tr>
+<td><graphic source="images/textDecoration.png" alt="TTML textDecoration style property"/></td>
+</tr>
+</tbody>
+</table>
+<note role="derivation">
+<p>The semantics of the style property
+represented by this attribute are based upon that defined by <bibref ref="xsl11"/>,
+&sect; 7.17.4.</p>
+</note>
+</div3>
+<div3 id="style-attribute-textOutline">
+<head>tts:textOutline</head>
+<p>The <att>tts:textOutline</att> attribute is used to specify a style property that
+defines a text outline effect to apply to glyphs that are selected for glyph areas generated
+by content flowed into a region.</p>
+<p>This attribute may be specified by any
+element type
+that permits use of attributes in the TT Style Namespace; however, this attribute applies
+as a style property only to those element types indicated in the following table.</p>
+<table id="style-property-details-textOutline" role="common">
+<col width="25%"/>
+<col/>
+<tbody>
+<tr>
+<td><emph>Values:</emph></td>
+<td>
+<code>none</code> |
+<loc href="#style-value-color">&lt;color&gt;</loc>?
+<loc href="#style-value-length">&lt;length&gt;</loc>
+<loc href="#style-value-length">&lt;length&gt;</loc>?
+</td>
+</tr>
+<tr>
+<td><emph>Initial:</emph></td>
+<td><code>none</code></td>
+</tr>
+<tr>
+<td><emph>Applies to:</emph></td>
+<td>
+<loc href="#content-vocabulary-span"><el>span</el></loc>
+</td>
+</tr>
+<tr>
+<td><emph>Inherited:</emph></td>
+<td>yes</td>
+</tr>
+<tr>
+<td><emph>Percentages:</emph></td>
+<td>relative to this element's font size</td>
+</tr>
+<tr>
+<td><emph>Animatable:</emph></td>
+<td>discrete</td>
+</tr>
+</tbody>
+</table>
+<p>For the purpose of determining applicability of this style property,
+each character child of a <el>p</el> element is considered to be enclosed in an anonymous
+span.</p>
+<p>The value of this attribute consists of an optional <loc href="#style-value-color">&lt;color&gt;</loc> term
+followed by one or two <loc href="#style-value-length">&lt;length&gt;</loc> terms.  If a <emph>color</emph> term is
+present, then it denotes the outline color; if no <emph>color</emph> term is
+present, the computed value of the <att>tts:color</att> applies.  The first
+<emph>length</emph> term denotes the outline thickness and the second length
+term, if present, indicates the blur radius.</p>
+<p>The <loc href="#style-value-length">&lt;length&gt;</loc> value(s) used to express thickness and blur radius must be non-negative.</p>
+<note role="elaboration">
+<p>When a <loc href="#style-value-length">&lt;length&gt;</loc> expressed in
+cells is used in a <att>tts:textOutline</att> value,
+the cell's dimension in the block progression dimension applies.
+For example, if text outline thickness is specified as 0.1c, the cell resolution
+is 20 by 10, and the extent of the <emph>Root Container Region</emph> is 640 by 480, then the
+outline thickness will be a nominal 480 / 10 * 0.1 pixels, i.e., 4.8px,
+without taking into account rasterization effects.</p>
+</note>
+<p>If a specified value of this attribute is not supported,
+then a presentation processor must interpret the attribute as if the
+value <code>none</code> were specified.</p>
+<p>The <att>tts:textOutline</att> style is illustrated by the following
+example.</p>
+<table id="style-attribute-textOutline-example-1" role="example">
+<caption>Example Fragment &ndash; Text Outline</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;region xml:id="r1"&gt;
+  &lt;style tts:backgroundColor="transparent"/&gt;
+  &lt;style tts:color="yellow"/&gt;
+  &lt;style <phrase role="strong">tts:textOutline="black 2px 0px"</phrase>/&gt;
+  &lt;style tts:fontFamily="proportionalSansSerif"/&gt;
+  &lt;style tts:fontSize="24px"/&gt;
+&lt;/region&gt;
+...
+&lt;p&gt;
+  How doth the little crocodile&lt;br/&gt;
+  Improve its shining tail,&lt;br/&gt;
+  And pour the waters of the Nile&lt;br/&gt;
+  On every golden scale!&lt;br/&gt;
+  How cheerfully he seems to grin,&lt;br/&gt;
+  How neatly spreads his claws,&lt;br/&gt;
+  And welcomes little fishes in,&lt;br/&gt;
+  With gently smiling jaws!
+&lt;/p&gt;
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p></p>
+<table id="style-attribute-textOutline-example-1-images" role="example-images">
+<caption>Example Rendition &ndash; Text Outline</caption>
+<tbody>
+<tr>
+<td><graphic source="images/textOutline.png" alt="backgroundColor style property"/></td>
+</tr>
+</tbody>
+</table>
+</div3>
+<div3 id="style-attribute-unicodeBidi">
+<head>tts:unicodeBidi</head>
+<p>The <att>tts:unicodeBidi</att> attribute is used to specify a style property that
+defines a directional embedding or override according to
+the Unicode bidirectional algorithm.</p>
+<p>This attribute may be specified by any
+element type
+that permits use of attributes in the TT Style Namespace; however, this attribute applies
+as a style property only to those element types indicated in the following table.</p>
+<table id="style-property-details-unicodeBidi" role="common">
+<col width="25%"/>
+<col/>
+<tbody>
+<tr>
+<td><emph>Values:</emph></td>
+<td>
+<code>normal</code> |
+<code>embed</code> |
+<code>bidiOverride</code>
+</td>
+</tr>
+<tr>
+<td><emph>Initial:</emph></td>
+<td>
+<code>normal</code>
+</td>
+</tr>
+<tr>
+<td><emph>Applies to:</emph></td>
+<td>
+<loc href="#content-vocabulary-p"><el>p</el></loc>,
+<loc href="#content-vocabulary-span"><el>span</el></loc>
+</td>
+</tr>
+<tr>
+<td><emph>Inherited:</emph></td>
+<td>no</td>
+</tr>
+<tr>
+<td><emph>Percentages:</emph></td>
+<td>N/A</td>
+</tr>
+<tr>
+<td><emph>Animatable:</emph></td>
+<td>discrete</td>
+</tr>
+</tbody>
+</table>
+<p>For the purpose of determining applicability of this style property,
+each character child of a <el>p</el> element is considered to be enclosed in an anonymous
+span.</p>
+<p>If a specified value of this attribute is not supported,
+then a presentation processor must interpret the attribute as if the
+value <code>normal</code> were specified.</p>
+<p>The <att>tts:unicodeBidi</att> style is illustrated by the following example.</p>
+<table id="style-attribute-unicodeBidi-example-1" role="example">
+<caption>Example Fragment &ndash; Unicode Bidirectionality</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;region xml:id="r1"&gt;
+  &lt;style tts:extent="265px 84px"/&gt;
+  &lt;style tts:padding="5px"/&gt;
+  &lt;style tts:backgroundColor="black"/&gt;
+  &lt;style tts:color="white"/&gt;
+  &lt;style tts:displayAlign="after"/&gt;
+  &lt;style tts:textAlign="center"/&gt;
+&lt;/region&gt;
+...
+&lt;p region="r1"&gt;
+  Little birds are playing&lt;br/&gt;
+  Bagpipes on the shore,&lt;br/&gt;
+  &lt;span <phrase role="strong">tts:unicodeBidi="bidiOverride"</phrase> tts:direction="rtl"&gt;where the tourists snore.&lt;/span&gt;
+&lt;/p&gt;
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p></p>
+<table id="style-attribute-unicodeBidi-example-1-images" role="example-images">
+<caption>Example Rendition &ndash; Unicode Bidirectionality</caption>
+<tbody>
+<tr>
+<td>
+<graphic source="images/unicodeBidi.png" alt="TTML unicodeBidi style property"/>
+</td>
+</tr>
+</tbody>
+</table>
+<note role="derivation">
+<p>The semantics of the style property
+represented by this attribute are based upon that defined by <bibref ref="xsl11"/>,
+&sect; 7.29.6.</p>
+</note>
+</div3>
+<div3 id="style-attribute-visibility">
+<head>tts:visibility</head>
+<p>The <att>tts:visibility</att> attribute is used to specify a style property that
+defines whether generated areas are visible or not when rendered on a visual
+presentation medium.</p>
+<p>This attribute may be specified by any
+element type
+that permits use of attributes in the TT Style Namespace; however, this attribute applies
+as a style property only to those element types indicated in the following table.</p>
+<table id="style-property-details-visibility" role="common">
+<col width="25%"/>
+<col/>
+<tbody>
+<tr>
+<td><emph>Values:</emph></td>
+<td>
+<code>visible</code> |
+<code>hidden</code>
+</td>
+</tr>
+<tr>
+<td><emph>Initial:</emph></td>
+<td>
+<code>visible</code>
+</td>
+</tr>
+<tr>
+<td><emph>Applies to:</emph></td>
+<td>
+<loc href="#document-structure-vocabulary-body"><el>body</el></loc>,
+<loc href="#content-vocabulary-div"><el>div</el></loc>,
+<loc href="#content-vocabulary-p"><el>p</el></loc>,
+<loc href="#layout-vocabulary-region"><el>region</el></loc>,
+<loc href="#content-vocabulary-span"><el>span</el></loc>
+</td>
+</tr>
+<tr>
+<td><emph>Inherited:</emph></td>
+<td>yes</td>
+</tr>
+<tr>
+<td><emph>Percentages:</emph></td>
+<td>N/A</td>
+</tr>
+<tr>
+<td><emph>Animatable:</emph></td>
+<td>discrete</td>
+</tr>
+</tbody>
+</table>
+<p>For the purpose of determining applicability of this style property,
+each character child of a <el>p</el> element is considered to be enclosed in an anonymous
+span.</p>
+<p>The <att>tts:visibility</att> style has no affect on content layout or
+composition, but merely determines whether composed content is visible or not.</p>
+<p>If a specified value of this attribute is not supported,
+then a presentation processor must interpret the attribute as if the
+value <code>visible</code> were specified.</p>
+<p>The <att>tts:visibility</att> style is illustrated by the following example.</p>
+<table id="style-attribute-visibility-example-1" role="example">
+<caption>Example Fragment &ndash; Visibility</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;region xml:id="r1"&gt;
+  &lt;style tts:extent="398px 121px"/&gt;
+  &lt;style tts:backgroundColor="black"/&gt;
+  &lt;style tts:color="white"/&gt;
+  &lt;style/&gt;
+&lt;/region&gt;
+...
+&lt;p region="r1" dur="4s"&gt;
+  &lt;span <phrase role="strong">tts:visibility="hidden"</phrase>&gt;
+    &lt;set begin="1s" <phrase role="strong">tts:visibility="visible"</phrase>/&gt;
+    Curiouser
+  &lt;/span&gt;
+  &lt;span <phrase role="strong">tts:visibility="hidden"</phrase>&gt;
+    &lt;set begin="2s" <phrase role="strong">tts:visibility="visible"</phrase>/&gt;
+    and
+  &lt;/span&gt;
+  &lt;span <phrase role="strong">tts:visibility="hidden"</phrase>&gt;
+    &lt;set begin="3s" <phrase role="strong">tts:visibility="visible"</phrase>/&gt;
+    curiouser!
+  &lt;/span&gt;
+&lt;/p&gt;
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p></p>
+<table id="style-attribute-visibility-example-1-images" role="example-images">
+<caption>Example Rendition &ndash; Visibility</caption>
+<tbody>
+<tr>
+<td>
+<graphic source="images/visibility_0.png" alt="TTML visibility style property - [0,1)"/>
+</td>
+</tr>
+<tr>
+<td>
+<graphic source="images/visibility_1.png" alt="TTML visibility style property - [1,2)"/>
+</td>
+</tr>
+<tr>
+<td>
+<graphic source="images/visibility_2.png" alt="TTML visibility style property - [2,3)"/>
+</td>
+</tr>
+<tr>
+<td>
+<graphic source="images/visibility_3.png" alt="TTML visibility style property - [3,4)"/>
+</td>
+</tr>
+</tbody>
+</table>
+<note role="derivation">
+<p>The semantics of the style property
+represented by this attribute are based upon that defined by <bibref ref="xsl11"/>,
+&sect; 7.30.17.</p>
+</note>
+</div3>
+<div3 id="style-attribute-wrapOption">
+<head>tts:wrapOption</head>
+<p>The <att>tts:wrapOption</att> attribute is used to specify a style property that
+defines whether or not automatic line wrapping (breaking) applies within the context of
+the affected element.</p>
+<p>This attribute may be specified by any
+element type
+that permits use of attributes in the TT Style Namespace; however, this attribute applies
+as a style property only to those element types indicated in the following table.</p>
+<table id="style-property-details-wrapOption" role="common">
+<col width="25%"/>
+<col/>
+<tbody>
+<tr>
+<td><emph>Values:</emph></td>
+<td>
+<code>wrap</code> |
+<code>noWrap</code>
+</td>
+</tr>
+<tr>
+<td><emph>Initial:</emph></td>
+<td><code>wrap</code></td>
+</tr>
+<tr>
+<td><emph>Applies to:</emph></td>
+<td>
+<loc href="#content-vocabulary-span"><el>span</el></loc>
+</td>
+</tr>
+<tr>
+<td><emph>Inherited:</emph></td>
+<td>yes</td>
+</tr>
+<tr>
+<td><emph>Percentages:</emph></td>
+<td>N/A</td>
+</tr>
+<tr>
+<td><emph>Animatable:</emph></td>
+<td>discrete</td>
+</tr>
+</tbody>
+</table>
+<p>For the purpose of determining applicability of this style property,
+each character child of a <el>p</el> element is considered to be enclosed in an anonymous
+span.</p>
+<p>If a specified value of this attribute is not supported,
+then a presentation processor must interpret the attribute as if the
+value <code>wrap</code> were specified.</p>
+<p>The <att>tts:wrapOption</att> style is illustrated by the following example.</p>
+<table id="style-attribute-wrapOption-example-1" role="example">
+<caption>Example Fragment &ndash; Wrap Option</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;region xml:id="r1"&gt;
+  &lt;style tts:extent="192px 117px"/&gt;
+  &lt;style tts:backgroundColor="black"/&gt;
+  &lt;style tts:color="white"/&gt;
+  &lt;style tts:displayAlign="after"/&gt;
+  &lt;style tts:overflow="hidden"/&gt;
+  &lt;style <phrase role="strong">tts:wrapOption="noWrap"</phrase>/&gt;
+&lt;/region&gt;
+...
+&lt;p&gt;
+  I'll tell thee everything I can:&lt;br/&gt;
+  There's little to relate.&lt;br/&gt;
+  I saw an aged aged man,&lt;br/&gt;
+  A-sitting on a gate.
+&lt;/p&gt;
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p></p>
+<table id="style-attribute-wrapOption-example-1-images" role="example-images">
+<caption>Example Rendition &ndash; Wrap Option</caption>
+<tbody>
+<tr>
+<td><graphic source="images/wrapOption.png" alt="TTML wrapOption style property"/></td>
+</tr>
+</tbody>
+</table>
+<note role="derivation">
+<p>The semantics of the style property
+represented by this attribute are based upon that defined by <bibref ref="xsl11"/>,
+&sect; 7.16.13.</p>
+</note>
+</div3>
+<div3 id="style-attribute-writingMode">
+<head>tts:writingMode</head>
+<p>The <att>tts:writingMode</att> attribute is used to specify a style property that
+defines the block and inline progression directions to be used for the purpose of
+stacking block and inline areas within a region area.</p>
+<p>This attribute may be specified by any
+element type
+that permits use of attributes in the TT Style Namespace; however, this attribute applies
+as a style property only to those element types indicated in the following table.</p>
+<table id="style-property-details-writingMode" role="common">
+<col width="25%"/>
+<col/>
+<tbody>
+<tr>
+<td><emph>Values:</emph></td>
+<td>
+<code>lrtb</code> |
+<code>rltb</code> |
+<code>tbrl</code> |
+<code>tblr</code> |
+<code>lr</code> |
+<code>rl</code> |
+<code>tb</code>
+</td>
+</tr>
+<tr>
+<td><emph>Initial:</emph></td>
+<td><code>lrtb</code></td>
+</tr>
+<tr>
+<td><emph>Applies to:</emph></td>
+<td>
+<loc href="#layout-vocabulary-region"><el>region</el></loc>
+</td>
+</tr>
+<tr>
+<td><emph>Inherited:</emph></td>
+<td>no</td>
+</tr>
+<tr>
+<td><emph>Percentages:</emph></td>
+<td>N/A</td>
+</tr>
+<tr>
+<td><emph>Animatable:</emph></td>
+<td>discrete</td>
+</tr>
+</tbody>
+</table>
+<p>If a specified value of this attribute is not supported,
+then a presentation processor must interpret the attribute as if the
+value <code>lrtb</code> were specified.</p>
+<p>The <att>tts:writingMode</att> style is illustrated by the following example.</p>
+<table id="style-attribute-writingMode-example-1" role="example">
+<caption>Example Fragment &ndash; Writing Mode</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;region xml:id="r1"&gt;
+  &lt;style tts:extent="50px 570px"/&gt;
+  &lt;style tts:origin="0px 0px"/&gt;
+  &lt;style tts:padding="10px 3px"/&gt;
+  &lt;style tts:backgroundColor="black"/&gt;
+  &lt;style tts:color="white"/&gt;
+  &lt;style <phrase role="strong">tts:writingMode="tbrl"</phrase>/&gt;
+&lt;/region&gt;
+&lt;region xml:id="r2"&gt;
+  &lt;style tts:extent="310px 50px"/&gt;
+  &lt;style tts:origin="70px 120px"/&gt;
+  &lt;style tts:padding="10px 3px"/&gt;
+  &lt;style tts:backgroundColor="black"/&gt;
+  &lt;style tts:color="white"/&gt;
+  &lt;style <phrase role="strong">tts:writingMode="rltb"</phrase>/&gt;
+&lt;/region&gt;
+...
+&lt;p region="r1"&gt;
+  I sometimes dig for buttered rolls,&lt;br/&gt;
+  Or set limed twigs for crabs:
+&lt;/p&gt;
+&lt;p region="r2" tts:direction="rtl" tts:unicodeBidi="bidiOverride"&gt;
+  I sometimes search the grassy knolls for the wheels of Hansom-cabs.
+&lt;/p&gt;
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p></p>
+<table id="style-attribute-writingMode-example-1-images" role="example-images">
+<caption>Example Rendition &ndash; Writing Mode</caption>
+<tbody>
+<tr>
+<td><graphic source="images/writingMode.png" alt="TTML writingMode style property"/></td>
+</tr>
+</tbody>
+</table>
+<note role="explanation">
+<p>In the second paragraph in the above example that targets region
+<code>r2</code>, the <att>tts:unicodeBidi</att> and
+<att>tts:direction</att> properties are set to
+<code>bidiOverride</code> and <code>rtl</code>, respectively, in order
+to override the normally left-to-right directionality of characters in
+the Latin script.</p>
+</note>
+<note role="derivation">
+<p>The semantics of the style property
+represented by this attribute are based upon that defined by <bibref ref="xsl11"/>,
+&sect; 7.29.7.</p>
+</note>
+</div3>
+<div3 id="style-attribute-zIndex">
+<head>tts:zIndex</head>
+<p>The <att>tts:zIndex</att> attribute is used to specify a style property that
+defines the front-to-back ordering of region areas in the case that they overlap.</p>
+<p>This attribute may be specified by any
+element type
+that permits use of attributes in the TT Style Namespace; however, this attribute applies
+as a style property only to those element types indicated in the following table.</p>
+<table id="style-property-details-zIndex" role="common">
+<col width="25%"/>
+<col/>
+<tbody>
+<tr>
+<td><emph>Values:</emph></td>
+<td>
+<code>auto</code> |
+<loc href="#style-value-integer">&lt;integer&gt;</loc>
+</td>
+</tr>
+<tr>
+<td><emph>Initial:</emph></td>
+<td><code>auto</code></td>
+</tr>
+<tr>
+<td><emph>Applies to:</emph></td>
+<td>
+<loc href="#layout-vocabulary-region"><el>region</el></loc>
+</td>
+</tr>
+<tr>
+<td><emph>Inherited:</emph></td>
+<td>no</td>
+</tr>
+<tr>
+<td><emph>Percentages:</emph></td>
+<td>N/A</td>
+</tr>
+<tr>
+<td><emph>Animatable:</emph></td>
+<td>discrete</td>
+</tr>
+</tbody>
+</table>
+<p>If two areas are associated with the same Z-index value, then, if those areas
+overlap in space, the area(s) generated by lexically subsequent elements must be
+rendered over area(s) generated by lexically prior elements, where lexical
+order is defined as the postorder traversal of a <emph>Document Instance</emph>.</p>
+<p>The semantics of the value <code>auto</code> are those defined by
+<bibref ref="xsl11"/>, &sect; 7.30.18, where the <el>tt</el> element
+is considered to establish the root stacking context.</p>
+<p>If a specified value of this attribute is not supported,
+then a presentation processor must interpret the attribute as if the
+value <code>auto</code> were specified.</p>
+<p>The <att>tts:zIndex</att> style is illustrated by the following example.</p>
+<table id="style-attribute-zIndex-example-1" role="example">
+<caption>Example Fragment &ndash; Z Index</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;region xml:id="r1"&gt;
+  &lt;style tts:origin="0px 0px"/&gt;
+  &lt;style tts:extent="400px 100px"/&gt;
+  &lt;style tts:padding="5px"/&gt;
+  &lt;style tts:backgroundColor="black"/&gt;
+  &lt;style tts:color="white"/&gt;
+  &lt;style <phrase role="strong">tts:zIndex="0"</phrase>/&gt;
+&lt;/region&gt;
+&lt;region xml:id="r2"&gt;
+  &lt;style tts:origin="100px 60px"/&gt;
+  &lt;style tts:extent="400px 100px"/&gt;
+  &lt;style tts:padding="5px"/&gt;
+  &lt;style tts:backgroundColor="red"/&gt;
+  &lt;style tts:color="white"/&gt;
+  &lt;style tts:textAlign="end"/&gt;
+  &lt;style <phrase role="strong">tts:zIndex="1"</phrase>/&gt;
+&lt;/region&gt;
+&lt;region xml:id="r3"&gt;
+  &lt;style tts:origin="0px 120px"/&gt;
+  &lt;style tts:extent="400px 100px"/&gt;
+  &lt;style tts:padding="5px"/&gt;
+  &lt;style tts:backgroundColor="black"/&gt;
+  &lt;style tts:color="white"/&gt;
+  &lt;style <phrase role="strong">tts:zIndex="2"</phrase>/&gt;
+&lt;/region&gt;
+&lt;region xml:id="r4"&gt;
+  &lt;style tts:origin="100px 180px"/&gt;
+  &lt;style tts:extent="400px 100px"/&gt;
+  &lt;style tts:padding="5px"/&gt;
+  &lt;style tts:backgroundColor="red"/&gt;
+  &lt;style tts:color="white"/&gt;
+  &lt;style tts:textAlign="end"/&gt;
+  &lt;style <phrase role="strong">tts:zIndex="3"</phrase>/&gt;
+&lt;/region&gt;
+...
+&lt;p region="r1"&gt;
+  I passed by his garden, and marked, with one eye,&lt;br/&gt;
+  How the Owl and the Panther were sharing a pie.
+&lt;/p&gt;
+&lt;p region="r2"&gt;
+  The Panther took pie-crust, and gravy, and meat,&lt;br/&gt;
+  While the Owl had the dish as its share of the treat.
+&lt;/p&gt;
+&lt;p region="r3"&gt;
+  When the pie was all finished, the Owl, as a boon,&lt;br/&gt;
+  Was kindly permitted to pocket the spoon:
+&lt;/p&gt;
+&lt;p region="r4"&gt;
+  While the Panther received knife and fork&lt;br/&gt;
+  with a growl,&lt;br/&gt;
+  And concluded the banquet by...
+&lt;/p&gt;
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p></p>
+<p></p>
+<table id="style-attribute-zIndex-example-1-images" role="example-images">
+<caption>Example Rendition &ndash; Z Index</caption>
+<tbody>
+<tr>
+<td><graphic source="images/zIndex.png" alt="TTML zIndex style property"/></td>
+</tr>
+</tbody>
+</table>
+<note role="derivation">
+<p>The semantics of the style property
+represented by this attribute are based upon that defined by <bibref ref="xsl11"/>,
+&sect; 7.30.18.</p>
+</note>
+</div3>
+</div2>
+<div2 id="styling-style-value-expressions">
+<head>Style Value Expressions</head>
+<p>Style property values include the use of the following expressions:</p>
+<ulist>
+<item><p><specref ref="style-value-alpha"/></p></item>
+<item><p><specref ref="style-value-color"/></p></item>
+<item><p><specref ref="style-value-digit"/></p></item>
+<item><p><specref ref="style-value-familyName"/></p></item>
+<item><p><specref ref="style-value-genericFamilyName"/></p></item>
+<item><p><specref ref="style-value-hexDigit"/></p></item>
+<item><p><specref ref="style-value-integer"/></p></item>
+<item><p><specref ref="style-value-length"/></p></item>
+<item><p><specref ref="style-value-namedColor"/></p></item>
+</ulist>
+<p>In the syntax representations defined in this section, no
+linear whitespace (LWSP) is implied or permitted between tokens
+unless explicitly specified.</p>
+<div3 id="style-value-alpha">
+<head>&lt;alpha&gt;</head>
+<p>An &lt;alpha&gt; expression is used to express an opacity value,
+where	0 means fully transparent and 1 means fully opaque.</p>
+<table id="alpha-style-expression-syntax" role="syntax">
+<caption>Syntax Representation &ndash; &lt;alpha&gt;</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;alpha&gt;
+  : <emph>float</emph>
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p>In the above syntax representation, the syntactic element
+<emph><code>float</code></emph> must adhere to the lexical
+representation defined by <bibref ref="xsd-2"/>&nbsp;&sect;
+3.2.4.1. If the value represented is less than 0.0,
+then it must be interpreted as equal to 0.0; similarly, if the value
+represented is greater than 1.0, then it must be interpreted as
+1.0. The value NaN must be interpreted as 0.0.</p>
+<p>A specified value for &lt;alpha&gt; should not be <code>NaN</code>,
+less than 0, or greater than 1.</p>
+<p>If a presentation processor does not support a specific,
+valid opacity value, then it must interpret it as being equal to the
+closest supported value.</p>
+</div3>
+<div3 id="style-value-color">
+<head>&lt;color&gt;</head>
+<p>A &lt;color&gt; expression is used to specify a named color, exact RGB color triple,
+or exact RGBA color tuple, where the alpha component, if expressed,
+is maximum (255) at 100% opacity
+and minimum (0) at 0% opacity, and where the applicable color space is
+defined by <bibref ref="srgb"/>.</p>
+<table id="color-style-expression-syntax" role="syntax">
+<caption>Syntax Representation &ndash; &lt;color&gt;</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;color&gt;
+  : "#" rrggbb
+  | "#" rrggbbaa
+  | "rgb" "(" r-value "," g-value "," b-value ")"
+  | "rgba" "(" r-value "," g-value "," b-value "," a-value ")"
+  | <loc href="#style-value-namedColor">&lt;namedColor&gt;</loc>
+
+rrggbb
+  :  <loc href="#style-value-hexDigit">&lt;hexDigit&gt;</loc>{6}
+
+rrggbbaa
+  :  <loc href="#style-value-hexDigit">&lt;hexDigit&gt;</loc>{8}
+
+r-value | g-value | b-value | a-value
+  : component-value
+
+component-value
+  : non-negative-integer                    // valid range: [0,255]
+
+non-negative-integer
+  : <loc href="#style-value-digit">&lt;digit&gt;</loc>+
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p>When expressing RGB component values, these values are considered
+to <phrase role="strong">not</phrase> be premultiplied by alpha.</p>
+<p>For the purpose of performing presentation processing such that
+non-opaque or non-transparent alpha or opacity values apply, then the
+semantics of compositing functions are defined with respect to the use of
+the <bibref ref="srgb"/> color space for both inputs and outputs of
+the composition function.</p>
+<note role="clarification">
+<p>The use of <bibref ref="srgb"/> for the stated semantics of
+composition is not meant to prevent an actual processor from using some
+other color space either for internal or external purposes. For
+example, a presentation processor may ultimately convert the SRGB values
+used here to the YUV color space for rendition on a television device.</p>
+</note>
+<p>If a presentation processor does not support a specific,
+valid color or alpha value, then it must interpret it as being equal
+to the closest supported value.</p>
+</div3>
+<div3 id="style-value-digit">
+<head>&lt;digit&gt;</head>
+<p>A &lt;digit&gt; is used to express integers and other types of numbers or tokens.</p>
+<table id="digit-style-expression-syntax" role="syntax">
+<caption>Syntax Representation &ndash; &lt;digit&gt;</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;digit&gt;
+  : "0" | "1" | "2" | "3" | "4" | "5" | "6" | "7" | "8" | "9"
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+</div3>
+<div3 id="style-value-duration">
+<head>Deleted</head>
+<note>
+<p>The information from this section has been removed due to lack of any normative
+use within this specification. This section is retained in its empty form
+in order to prevent section renumbering.</p>
+</note>
+</div3>
+<div3 id="style-value-familyName">
+<head>&lt;familyName&gt;</head>
+<p>A &lt;familyName&gt; expression specifies a font family name.</p>
+<table id="familyName-style-expression-syntax" role="syntax">
+<caption>Syntax Representation &ndash; &lt;familyName&gt;</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;familyName&gt;
+  : unquoted-string
+  | quoted-string
+
+unquoted-string
+  : identifier ( lwsp identifier )*
+
+lwsp
+  : ( ' ' | '\t' | '\n' | '\r' )+
+
+identifier
+  : [-]? identifier-start identifier-following*
+
+identifier-start
+  : [_a-zA-Z]
+  | non-ascii-or-c1
+  | escape
+
+identifier-following
+  : [_a-zA-Z0-9-]
+  | non-ascii-or-c1
+  | escape
+
+non-ascii-or-c1
+  : [^\0-\237]
+
+escape
+  : '\\' <emph>char</emph>
+
+quoted-string
+  : double-quoted-string
+  | single-quoted-string
+
+double-quoted-string
+  : '"' ( [^"\\] | escape )+ '"'
+
+single-quoted-string
+  : "'" ( [^'\\] | escape )+ "'"
+</eg>
+<!-- " -->
+</td>
+</tr>
+</tbody>
+</table>
+<p>In addition to adhering to the syntax rules specified above, the following semantic rules apply:</p>
+<ulist>
+<item><p>the semantic value of a &lt;familyName&gt; expression is the semantic value of its <code>unquoted-string</code> or <code>quoted-string</code>
+non-terminal, according to whichever applies;</p></item>
+<item><p>the semantic value of an <code>unquoted-string</code> non-terminal is a pair <code>&lt;</code><emph>quoted</emph>, <emph>content</emph><code>&gt;</code>,
+where <emph>quoted</emph> is a boolean <code>false</code>, and
+where <emph>content</emph> is the result of appending the value of each <code>identifier</code>
+non-terminal, in lexical order, where the value of each identifier is preceded by a single SPACE (U+0020) character if it is not the first
+identifier;</p></item>
+<item><p>the semantic value of a <code>quoted-string</code> non-terminal is a pair <code>&lt;</code><emph>quoted</emph>, <emph>content</emph><code>&gt;</code>,
+where <emph>quoted</emph> is a boolean <code>true</code>, and
+where <emph>content</emph> is the unquoted content of the quoted string, i.e., the sequence of characters between the delimiting quotes.</p></item>
+<item><p>the semantic value of an <code>escape</code> non-terminal is the value of the escaped <code>char</code>;</p></item>
+<item><p>a &lt;familyName&gt; that takes the form of an <code>unquoted-string</code> that contains an <code>identifier</code> that
+starts with two <code>-</code> HYPHEN-MINUS (U+002D) characters must be considered to be invalid;</p></item>
+<item><p>a &lt;familyName&gt; that takes the form of an <code>unquoted-string</code> that contains a single <code>identifier</code> that
+matches (by case sensitive comparison) a &lt;genericFamilyName&gt; must be interpreted as that &lt;genericFamilyName&gt;;</p></item>
+<item><p>a &lt;familyName&gt; that takes the form of a <code>quoted-string</code> whose content (unquoted value)
+matches (by case sensitive comparison) a &lt;genericFamilyName&gt; must not be interpreted as that &lt;genericFamilyName&gt;, but as
+the actual name of a non-generic font family.</p></item>
+</ulist>
+<note role="notation">
+<p>The syntactic element <emph><code>char</code></emph> is to be interpreted according
+to the <code>Char</code> production defined by <bibref ref="xml10"/>&nbsp;&sect;2.2.</p>
+</note>
+<note role="elaboration">
+<p>The <code>{unicode}</code> escape mechanism defined by <bibref ref="css2"/>&nbsp;&sect;4.1.1
+is not supported by this syntax; rather, authors are expected to either (1) directly encode the character
+using the document encoding or (2) use an XML character reference according to
+<bibref ref="xml10"/>&nbsp;&sect;4.1. When a syntactically significant character needs to be used
+without its normal syntactic interpretation, it may be be escaped using the backslash
+(reverse solidus) <code>escape</code> non-terminal specified above.</p>
+<p>When using the backslash (reverse solidus) <code>escape</code> non-terminal, the above syntax does
+not place any restriction on what character may be escaped, e.g., <code>\\[\n\r\f0-9a-f]</code> are
+permitted. If one of these latter escapes appears in a &lt;familyName&gt; expression, then it will
+need to be converted to a <code>{unicode}</code> escape if it is to be used with a standard XSL-FO
+or CSS parser. In particular, a backslash followed by a newline is ignored by CSS, while it is not
+ignored by the above syntax. Such an unignored escaped newline would need to be represented using
+an equivalent <code>{unicode}</code> escape, such as <code>\a</code>, to order to express in CSS.</p>
+</note>
+</div3>
+<div3 id="style-value-genericFamilyName">
+<head>&lt;genericFamilyName&gt;</head>
+<p>A &lt;genericFamilyName&gt; expression specifies a font family using a general
+token that indicates a class of font families.</p>
+<p>The resolution of a generic family name to a concrete font instance is considered to
+be implementation dependent, both in the case of content authoring and content interpretation.</p>
+<table id="genericFamilyName-style-expression-syntax" role="syntax">
+<caption>Syntax Representation &ndash; &lt;genericFamilyName&gt;</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;genericFamilyName&gt;
+  : "default"
+  | "monospace"
+  | "sansSerif"
+  | "serif"
+  | "monospaceSansSerif"
+  | "monospaceSerif"
+  | "proportionalSansSerif"
+  | "proportionalSerif"
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p>The mapping between a generic (font) family name and an actual font is not
+determined by this specification; however, the
+distinction of monospace versus proportional and serif versus sans-serif
+should be maintained if possible when performing presentation.</p>
+<p>If a generic (font) family name of <code>monospace</code> is specified,
+then it may be interpreted as equivalent to either <code>monospaceSansSerif</code>
+or <code>monospaceSerif</code>. The generic family names <code>sansSerif</code>
+and <code>serif</code> are to be interpreted as equivalent to <code>proportionalSansSerif</code>
+and <code>proportionalSerif</code>, respectively.</p>
+<p>If the generic family name <code>default</code> is specified (or implied by
+an initial value), then its typographic characteristics are considered to be implementation
+dependent; however, it is recommended that this default font family be mapped to
+an monospaced, sans-serif font.</p>
+</div3>
+<div3 id="style-value-hexDigit">
+<head>&lt;hexDigit&gt;</head>
+<p>A &lt;hexDigit&gt; is used to express integers and other types of numbers or tokens
+that employ base 16 arithmetic.</p>
+<p>For the purpose of parsing, a distinction must not be made between lower and upper case.</p>
+<table id="hexDigit-style-expression-syntax" role="syntax">
+<caption>Syntax Representation &ndash; &lt;hexDigit&gt;</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;hexDigit&gt;
+  : <loc href="#style-value-digit">&lt;digit&gt;</loc>
+  | "a" | "b" | "c" | "d" | "e" | "f"
+  | "A" | "B" | "C" | "D" | "E" | "F"
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+</div3>
+<div3 id="style-value-integer">
+<head>&lt;integer&gt;</head>
+<p>An &lt;integer&gt; expression is used to express an arbitrary, signed integral value.</p>
+<table id="integer-style-expression-syntax" role="syntax">
+<caption>Syntax Representation &ndash; &lt;integer&gt;</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;integer&gt;
+  : ( "+" | "-" )? <loc href="#style-value-digit">&lt;digit&gt;</loc>+
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+</div3>
+<div3 id="style-value-length">
+<head>&lt;length&gt;</head>
+<p>A &lt;length&gt; expression is used to express either a coordinate component of point
+in a cartesian space or a distance between two points in a cartesian space.</p>
+<table id="length-style-expression-syntax" role="syntax">
+<caption>Syntax Representation &ndash; &lt;length&gt;</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;length&gt;
+  : scalar
+  | percentage
+
+scalar
+  : number units
+
+percentage
+  : number "%"
+
+sign
+  : "+" | "-"
+
+number
+  : sign? non-negative-number
+
+non-negative-number
+  : non-negative-integer
+  | non-negative-real
+
+non-negative-integer
+  : <loc href="#style-value-digit">&lt;digit&gt;</loc>+
+
+non-negative-real
+  : <loc href="#style-value-digit">&lt;digit&gt;</loc>* "." <loc href="#style-value-digit">&lt;digit&gt;</loc>+
+
+units
+  : "px"
+  | "em"
+  | "c"                                     // abbreviation of "cell"
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p>It is an error to omit the units component of a scalar length
+value.</p>
+<p>The semantics of
+the unit of measure <code>px</code> (pixel) 
+are as defined by <bibref ref="xsl11"/>, &sect; 5.9.13.</p>
+<p>When specified relative to a font whose size is expressed as a single length
+measure or as two length measures of equal length, the unit of measure <code>em</code> is considered to be
+identical to that defined by <bibref ref="xsl11"/>, &sect; 5.9.13;
+however, when specified relative to a font whose size is expressed as
+two length measures of non-equal lengths, then one <code>em</code> is
+equal to the inline progression dimension of the anamorphically
+scaled font when used to specify lengths in the inline progression
+direction and equal to the block progression dimension of the scaled
+font when used to specify lengths in the block progression direction.</p>
+<p>The semantics of the unit of measure <code>c</code> (cell) are
+defined by the parameter <specref
+ref="parameter-attribute-cellResolution"/>.</p>
+</div3>
+<div3 id="style-value-namedColor">
+<head>&lt;namedColor&gt;</head>
+<p>A &lt;namedColor&gt; is used to express an RGBA color with a convenient name, and where the applicable color space is
+defined by <bibref ref="srgb"/>.</p>
+<p>For the purpose of parsing, a distinction must not be made between lower and upper case.</p>
+<table id="namedColor-style-expression-syntax" role="syntax">
+<caption>Syntax Representation &ndash; &lt;namedColor&gt;</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;namedColor&gt;
+  : "transparent"                           // #00000000
+  | "black"                                 // #000000ff
+  | "silver"                                // #c0c0c0ff
+  | "gray"                                  // #808080ff
+  | "white"                                 // #ffffffff
+  | "maroon"                                // #800000ff
+  | "red"                                   // #ff0000ff
+  | "purple"                                // #800080ff
+  | "fuchsia"                               // #ff00ffff
+  | "magenta"                               // #ff00ffff (= fuchsia)
+  | "green"                                 // #008000ff
+  | "lime"                                  // #00ff00ff
+  | "olive"                                 // #808000ff
+  | "yellow"                                // #ffff00ff
+  | "navy"                                  // #000080ff
+  | "blue"                                  // #0000ffff
+  | "teal"                                  // #008080ff
+  | "aqua"                                  // #00ffffff
+  | "cyan"                                  // #00ffffff (= aqua)
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<note role="clarification">
+<p>Except for <code>transparent</code>, the set of named colors specified above constitutes a proper
+subset of the set of named colors specified by <bibref ref="svg11"/>, &sect; 4.2.</p>
+</note>
+</div3>
+<div3 id="style-value-quotedString">
+<head>Deleted</head>
+<note>
+<p>The information from this section has been incorporated into
+<specref ref="style-value-familyName"/>. This section is retained in its empty form
+in order to prevent section renumbering.</p>
+</note>
+</div3>
+<div3 id="style-value-string">
+<head>Deleted</head>
+<note>
+<p>The information from this section has been incorporated into
+<specref ref="style-value-familyName"/>. This section is retained in its empty form
+in order to prevent section renumbering.</p>
+</note>
+</div3>
+</div2>
+<div2 id="semantics-style-resolution">
+<head>Style Resolution</head>
+<p>This section defines the semantics of style resolution in terms of
+a standard processing model as follows:</p>
+<ulist>
+<item><p><specref ref="semantics-style-association"/></p></item>
+<item><p><specref ref="semantics-style-inheritance"/></p></item>
+<item><p><specref ref="semantics-style-resolution-value-categories"/></p></item>
+<item><p><specref ref="semantics-style-resolution-processing"/></p></item>
+</ulist>
+<p>Any implementation of this model is permitted provided that the
+externally observable results are consistent with the results produced
+by this model.</p>
+<note role="derivation">
+<p>The semantics of style resolution employed here are based upon
+<bibref ref="xsl11"/>, &sect; 5.</p>
+</note>
+<div3 id="semantics-style-association">
+<head>Style Association</head>
+<p>Style association is a sub-process of <specref
+ref="semantics-style-resolution-processing"/> used to determine the
+specified style set of each content and
+layout element.</p>
+<p>Style matter may be associated with content
+ and layout matter in a number of ways:</p>
+<ulist>
+<item><p><loc href="#semantics-style-association-inline">inline styling</loc></p></item>
+<item><p><loc href="#semantics-style-association-referential">referential styling</loc></p></item>
+<item><p><loc href="#semantics-style-association-chained-referential">chained referential styling</loc></p></item>
+</ulist>
+<p>In addition to the above, style matter may be associated with layout matter using:</p>
+<ulist>
+<item><p><loc href="#semantics-style-association-nested">nested styling</loc></p></item>
+</ulist>
+<div4 id="semantics-style-association-inline">
+<head>Inline Styling</head>
+<p>Style properties may be expressed in an inline manner by direct
+specification of an attribute from the TT Style Namespace on the
+affected element. When expressed in this manner, the association of
+style information is referred to as <emph>inline styling</emph>.</p>
+<p>Style properties associated by inline styling are afforded a higher priority than all other
+forms of style association.</p>
+<table id="style-association-example-1" role="example">
+<caption>Example &ndash; Inline Styling</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;p <phrase role="strong">tts:color="white"</phrase>&gt;White 1&nbsp;&lt;span <phrase role="strong">tts:color="yellow"</phrase>&gt;Yellow&lt;/span&gt;&nbsp;White 2&lt;/p&gt;
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<note role="explanation">
+<p>In the above example, the two text fragments <code>"White 1 "</code> and
+<code>" White 2"</code>, which are interpreted as anonymous spans, are not
+associated with a color style property; rather, they inherit their color style
+from their parent <el>p</el> element as described in <specref
+ref="semantics-style-inheritance-content"/> below.  </p>
+</note>
+</div4>
+<div4 id="semantics-style-association-referential">
+<head>Referential Styling</head>
+<p>Style properties may be expressed in an out-of-line manner and referenced by the
+affected element using the <att>style</att> attribute. When expressed in this manner,
+the association of style information is referred to as <emph>referential styling</emph>.</p>
+<p>If a <att>style</att> attribute specifies multiple references, then those references are
+evaluated in the specified order, and that order applies to resolution of the value of a
+style property in the case that it is specified along multiple reference paths.</p>
+<p>The use of referential styling is restricted to making
+reference to <el>style</el> element descendants of a <el>styling</el>
+element. It is considered an error to reference a <el>style</el>
+element that is a descendant of a <el>layout</el> element.</p>
+<note role="explanation">
+<p>The use of referential styling encourages the reuse of style specifications while
+sacrificing locality of reference.</p>
+</note>
+<note role="explanation">
+<p>A single content element may be associated with style properties by a hybrid mixture of
+inline and referential styling, in which case inline styling is given priority as described above
+by <specref ref="semantics-style-association-inline"/>.</p>
+</note>
+<table id="style-association-example-2" role="example">
+<caption>Example &ndash; Referential Styling</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;style <phrase role="strong">xml:id="s1"</phrase> tts:color="white"/&gt;
+&lt;style <phrase role="strong">xml:id="s2"</phrase> tts:color="yellow"/&gt;
+...
+&lt;p <phrase role="strong">style="s1"</phrase>&gt;White 1&nbsp;&lt;span <phrase role="strong">style="s2"</phrase>&gt;Yellow&lt;/span&gt;&nbsp;White 2&lt;/p&gt;
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<note role="explanation">
+<p>In the above example, the two text fragments <code>"White 1 "</code> and
+<code>" White 2"</code>, which are interpreted as anonymous spans, are not
+associated with a color style property; rather, they inherit their color style
+from their parent <el>p</el> element as described in <specref
+ref="semantics-style-inheritance-content"/> below.</p>
+</note>
+</div4>
+<div4 id="semantics-style-association-chained-referential">
+<head>Chained Referential Styling</head>
+<p>Style properties may be expressed in an out-of-line manner and may themselves reference
+other out-of-line style properties, thus creating a chain of references starting at the
+affected element. When expressed in this manner, the association of style information
+is referred to as <emph>chained referential styling</emph>.</p>
+<p>If the same style property is specified in more than one referenced
+style set, then the last referenced style set applies, where the order of application starts from
+the affected element and proceeds to referenced style sets, and, in turn, to subsequent referenced style sets.</p>
+<p>A loop in a sequence of chained style references must be considered an error.</p>
+<p>The use of referential styling is restricted to making
+reference to <el>style</el> element descendants of a <el>styling</el>
+element. It is considered an error to reference a <el>style</el>
+element that is a descendant of a <el>layout</el> element.</p>
+<note role="explanation">
+<p>The use of chained referential styling encourages the grouping of style specifications
+into general and specific sets, which further aids in style specification reuse.</p>
+</note>
+<note role="explanation">
+<p>A single content element may be associated with style properties by a hybrid mixture of
+inline, referential styling, and chained referential styling, in which case inline styling is
+given priority as described above by <specref ref="semantics-style-association-inline"/>.</p>
+</note>
+<table id="style-association-example-3" role="example">
+<caption>Example &ndash; Chained Referential Styling</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;style <phrase role="strong">xml:id="s1"</phrase> tts:color="white" tts:fontFamily="monospaceSerif"/&gt;
+&lt;style <phrase role="strong">xml:id="s2"</phrase> <phrase role="strong">style="s1"</phrase> tts:color="yellow"/&gt;
+...
+&lt;p <phrase role="strong">style="s1"</phrase>&gt;White Monospace&lt;/p&gt;
+&lt;p <phrase role="strong">style="s2"</phrase>&gt;Yellow Monospace&lt;/p&gt;
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+</div4>
+<div4 id="semantics-style-association-nested">
+<head>Nested Styling</head>
+<p>Style properties may be expressed in a nested manner by direct specification of one or
+more <el>style</el> element children of the affected element.
+When expressed in this manner, the association of style information
+is referred to as <emph>nested styling</emph>.</p>
+<p>Style properties associated by nested styling are afforded a lower priority than inline
+styling but with higher priority than referential styling.</p>
+<table id="style-association-example-4" role="example">
+<caption>Example &ndash; Nested Styling</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;region xml:id="r1"&gt;
+  <phrase role="strong">&lt;style tts:extent="128px 66px"/&gt;</phrase>
+  <phrase role="strong">&lt;style tts:origin="0px 0px"/&gt;</phrase>
+  <phrase role="strong">&lt;style tts:displayAlign="center"/&gt;</phrase>
+&lt;/region&gt;
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<note role="clarification">
+<p>In this version of this specification, nested styling applies only
+to the <el>region</el> element.</p>
+</note>
+</div4>
+</div3>
+<div3 id="semantics-style-inheritance">
+<head>Style Inheritance</head>
+<p>Style inheritance is a sub-process of <specref
+ref="semantics-style-resolution-processing"/> used to determine the
+specified style set of each content and
+layout element.</p>
+<p>Styles are further propagated to content matter
+using:
+</p>
+<ulist>
+<item><p><loc href="#semantics-style-inheritance-content">content style inheritance</loc></p></item>
+<item><p><loc href="#semantics-style-inheritance-content">region style inheritance</loc></p></item>
+</ulist>
+<p>For the purpose of determining inherited styles, the element hierarchy of
+an intermediate synchronic document form of a <emph>Document Instance</emph> must be used, where
+such intermediate forms are defined by <specref ref="semantics-region-layout-step-1"/>.</p>
+<note role="explanation">
+<p>The intermediate synchronic document form is utilized rather than
+the original form in order to facilitate region inheritance
+processing.</p>
+</note>
+<div4 id="semantics-style-inheritance-content">
+<head>Content Style Inheritance</head>
+<p>Style properties are inherited from ancestor content elements
+within an intermediate synchronic document
+if a style property is not associated with a content element (or
+an anonymous span) and the style property is designated as
+inheritable.</p>
+<p>If a style property is determined to require inheritance, then the inherited value must
+be the value of the same named style property in the computed
+style set of the
+element's immediate ancestor element
+within the applicable intermediate synchronic document.</p>
+<table id="style-inheritance-example-2" role="example">
+<caption>Example &ndash; Content Style Inheritance</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;p <phrase role="strong">tts:fontFamily="monospaceSansSerif"</phrase>&gt;
+  &lt;span tts:color="yellow"&gt;Yellow Monospace&lt;/span&gt;
+&lt;/p&gt;
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<note role="explanation">
+<p>In the above example, the <el>span</el> element that encloses the character items
+<code>Yellow Monospace</code> is not associated with a <att>tts:fontFamily</att> style
+property and this property is inheritable; therefore, the value of the
+<att>tts:fontFamily</att> style
+is inherited from the computed style
+set of the ancestor <el>p</el> element,
+and is added to the
+specified
+style
+set of the <el>span</el> element.</p>
+</note>
+</div4>
+<div4 id="semantics-style-inheritance-region">
+<head>Region Style Inheritance</head>
+<p>Style properties are inherited from a region element in the following case:</p>
+<olist>
+<item><p>if a style property <emph>P</emph> is not associated with
+a content
+element or an anonymous span <emph>E</emph> and the style
+property is designated as inheritable, and</p></item> <item><p>if that
+style property <emph>P</emph> is in the computed style
+set of region
+<emph>R</emph>,
+and</p></item>
+<item><p>if that element <emph>E</emph> is flowed into (presented within) region
+<emph>R</emph>.</p></item>
+</olist>
+<table id="style-inheritance-example-3" role="example">
+<caption>Example &ndash; Region Style Inheritance</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;region <phrase role="strong">xml:id="r1"</phrase>&gt;
+&nbsp;&nbsp;&lt;style tts:color="yellow"/&gt;
+&nbsp;&nbsp;&lt;style tts:fontFamily="monospaceSerif"/&gt;
+&lt;/region&gt;
+...
+&lt;p <phrase role="strong">region="r1"</phrase>&gt;Yellow Monospace&lt;/p&gt;
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<note role="explanation">
+<p>In the above example, the anonymous span that encloses the character
+items <code>Yellow Monospace</code> effectively inherits the <att>tts:color</att>
+and <att>tts:fontFamily</att> styles specified on the <el>region</el>
+element into which the <el>p</el> element is flowed (presented).</p>
+</note>
+</div4>
+</div3>
+<div3 id="semantics-style-resolution-value-categories">
+<head>Style Resolution Value Categories</head>
+<p>During style resolution, layout, and presentation processing,
+three categories of style property values are distinguished as
+follows:</p>
+<ulist>
+<item><p><loc href="#semantics-style-resolved-value-category-specified">specified values</loc></p></item>
+<item><p><loc href="#semantics-style-resolved-value-category-computed">computed values</loc></p></item>
+<item><p><loc href="#semantics-style-resolved-value-category-actual">actual values</loc></p></item>
+</ulist>
+<div4 id="semantics-style-resolved-value-category-specified">
+<head>Specified Values</head>
+<p>Values of style properties that are associated with or inherited
+by an element or anonymous span are referred to as <emph>specified values</emph>. The
+set of all specified style properties of a given element is referred to
+as the <emph>specified style set</emph> of that element.</p>
+</div4>
+<div4 id="semantics-style-resolved-value-category-computed">
+<head>Computed Values</head>
+<p>When style properties are specified using relative value expressions,
+such as a named color, a relative unit (e.g., cell), or a percentage, then
+they need to be further resolved into absolute units, such as an RGB triple,
+pixels, etc.</p>
+<p>During the style resolution process, all specified style values are
+reinterpreted (or recalculated) in absolute terms, and then recorded as
+<emph>computed values</emph>. The
+set of all computed style properties of a given element is referred to
+as the <emph>computed style set</emph> of that element.</p>
+<p>When a style value is inherited, either explicitly or implicitly, it
+is the computed value of the style that is inherited from an ancestor
+element. This is required since the resolution of certain relative units,
+such as percentage, require evaluating the expression in the immediate
+(local) context of reference, and not in a distant (remote) context of
+reference where the related (resolving) expression is not available.</p>
+</div4>
+<div4 id="semantics-style-resolved-value-category-actual">
+<head>Actual Values</head>
+<p>During the actual presentation process, other transformations occur
+that map some value expressions to concrete, physical values. For example,
+the colors of computed style values are further subjected to closest color
+approximation and gamma correction
+during the display process. In addition, length value expressions that use
+pixels in computed style values are considered to express logical rather than
+physical (device) pixels. Consequently, these logical pixels are subject to
+being further transformed or mapped to physical (device) pixels during
+presentation.</p>
+<p>The final values that result from the logical to device mapping
+process are referred to as <emph>actual values</emph>.  The set of all
+actual style properties of a given element is referred to as the
+<emph>actual style set</emph> of that element.</p>
+<note role="elaboration">
+<p>More than one set of actual values may be produced during the
+process of presentation. For example, a TTML presentation processor
+device may output an RGBA component video signal which is then
+further transformed by an NTSC or PAL television to produce a final
+image. In this case, both color and dimensions may further be modified
+prior to presentation.</p>
+</note>
+<note role="explanation">
+<p>In general, a TTML presentation processor will not have access
+to actual style set values; as a consequence, no further use or reference
+to actual values is made below when formally describing the style
+resolution process.</p>
+</note>
+</div4>
+</div3>
+<div3 id="semantics-style-resolution-processing">
+<head>Style Resolution Processing</head>
+<p>The process of style resolution is defined herein as the procedure
+(and results thereof) for resolving (determining) the computed values
+of all style properties that apply to content and layout elements:</p>
+<ulist>
+<item><p><specref ref="semantics-style-resolution-processing-definitions"/></p></item>
+<item><p><specref ref="semantics-style-resolution-processing-sss"/></p></item>
+<item><p><specref ref="semantics-style-resolution-processing-css"/></p></item>
+<item><p><specref ref="semantics-style-resolution-process-overall"/></p></item>
+</ulist>
+<p>The process described here forms an integral sub-process of
+<specref ref="semantics-region-layout"/>.</p>
+<div4 id="semantics-style-resolution-processing-definitions">
+<head>Conceptual Definitions</head>
+<p>For the purpose of interpreting the style resolution processing
+model specified below, the following conceptual definitions apply:</p>
+<glist>
+<gitem>
+<label>[style property]</label>
+<def>
+<p>a style property, <emph>P</emph>, is considered to consist of a
+tuple <code>[name, value]</code>, where the name of the
+property is a tuple <code>[namespace value,
+unqualified name]</code> and the value of the property is a
+tuple <code>[category, type, value expression]</code></p>
+<table id="conceptual-definition-example-style-property" role="example">
+<caption>Example &ndash; conceptual style property</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+[
+  ["http://www.w3.org/ns/ttml#styling", "color"],
+  ["specified", <emph>color</emph>, "red"]
+]
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p></p>
+</def>
+</gitem>
+<gitem>
+<label>[style (property) set]</label>
+<def>
+<p>a style (property) set consists of an unordered collection of style
+properties, where no two style properties within the set have an
+identical name, where by "identical name" is meant equality of
+namespace value of name tuple and unqualified name of name tuple;</p>
+<p>in a specified style (property) set, the category of each style
+property is "specified"; a specified style (property) set of an
+element <emph>E</emph> is referred to as <emph>SSS(E)</emph>;</p>
+<table id="conceptual-definition-example-specified-style-set" role="example">
+<caption>Example &ndash; conceptual (specified) style (property) set</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+{
+  [
+    ["http://www.w3.org/ns/ttml#styling", "backgroundColor"],
+    ["specified", <emph>color</emph>, 0x00FF00 ]
+  ],
+  [
+    ["http://www.w3.org/ns/ttml#styling", "color"],
+    ["specified", <emph>color</emph>, "red" ]
+  ],
+  [
+    ["http://www.w3.org/ns/ttml#styling", "fontSize"],
+    ["specified", <emph>length</emph>, "1c" ]
+  ],
+  [
+    ["http://www.w3.org/ns/ttml#styling", "lineHeight"],
+    ["specified", <emph>length</emph>, "117%" ]
+  ]
+}
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p>in a computed style (property) set, the category of each style
+property is either "specified" or "computed"; a computed style (property) set of an element
+<emph>E</emph> is referred to as <emph>CSS(E)</emph>;</p>
+<table id="conceptual-definition-example-computed-style-set" role="example">
+<caption>Example &ndash; conceptual (computed) style (property) set</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+{
+  [
+    ["http://www.w3.org/ns/ttml#styling", "backgroundColor"],
+    ["specified", <emph>color</emph>, 0x00FF00 ]
+  ],
+  [
+    ["http://www.w3.org/ns/ttml#styling", "color"],
+    ["computed", <emph>color</emph>, 0xFF0000 ]
+  ],
+  [
+    ["http://www.w3.org/ns/ttml#styling", "fontSize"],
+    ["computed", <emph>length</emph>, "24px" ]
+  ],
+  [
+    ["http://www.w3.org/ns/ttml#styling", "lineHeight"],
+    ["computed", <emph>length</emph>, "28px" ]
+  ]
+}
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p></p>
+</def>
+</gitem>
+<gitem>
+<label>[style (property) merging]</label>
+<def>
+<p>a style property <emph>P<sub>new</sub></emph> is merged into a
+style (property) set, <emph>SS</emph>, as follows: if a style property
+<emph>P<sub>old</sub></emph> is already present in <emph>SS</emph>
+where the name of <emph>P<sub>new</sub></emph> is identical to the
+name of <emph>P<sub>old</sub></emph>, then replace
+<emph>P<sub>old</sub></emph> in <emph>SS</emph> with
+<emph>P<sub>new</sub></emph>; otherwise, add
+<emph>P<sub>new</sub></emph> to <emph>SS</emph>;</p>
+</def>
+</gitem>
+<gitem>
+<label>[style (property) set merging]</label>
+<def>
+<p>a style (property) set <emph>SS<sub>new</sub></emph> is merged into
+an existing style (property) set <emph>SS<sub>old</sub></emph> as
+follows: for each style property <emph>P<sub>new</sub></emph> in
+<emph>SS<sub>new</sub></emph>, merge <emph>P<sub>new</sub></emph> into
+<emph>SS<sub>old</sub></emph>;</p>
+</def>
+</gitem>
+</glist>
+</div4>
+<div4 id="semantics-style-resolution-processing-sss">
+<head>Specified Style Set Processing</head>
+<p>The specified style set <emph>SSS</emph> of an element or
+anonymous span <emph>E</emph>,
+<emph>SSS(E)</emph>, is determined according to the following ordered
+rules:</p>
+<olist>
+<item><p><phrase role="strong">[initialization]</phrase> initialize
+the specified style set <emph>SSS</emph> of <emph>E</emph> to the
+empty set;</p></item>
+<item><p><phrase role="strong">[referential and chained referential
+styling]</phrase> for each <el>style</el> element <emph>S<sub>REF</sub></emph>
+referenced by a <att>style</att> attribute specified on
+<emph>E</emph>, and in the order specified in the <att>style</att>
+attribute, then, if <emph>S<sub>REF</sub></emph> is a descendant
+of a <el>styling</el> element,
+merge the specified style set of
+<emph>S<sub>REF</sub></emph>, <emph>SSS(S<sub>REF</sub>)</emph>, into
+the specified style set of <emph>E</emph>,
+<emph>SSS(E)</emph>;</p></item>
+<item><p><phrase role="strong">[nested styling]</phrase> for each
+nested <el>style</el> element child <emph>S<sub>NEST</sub></emph> of
+<emph>E</emph>, and in the specified order of child elements, merge
+the specified style set of <emph>S<sub>NEST</sub></emph>,
+<emph>SSS(S<sub>NEST</sub>)</emph>, into the specified style set of
+<emph>E</emph>, <emph>SSS(E)</emph>;</p></item>
+<item><p><phrase role="strong">[inline styling]</phrase> for each
+style property <emph>P</emph> expressed as a specified styling
+attribute of <emph>E</emph>,
+merge <emph>P</emph> into the specified style
+set of <emph>E</emph>, <emph>SSS(E)</emph>;</p></item>
+<item><p><phrase role="strong">[animation styling]</phrase> for each
+style property <emph>P</emph> expressed as a specified styling
+attribute of an immediate animation (<el>set</el>) element child of element <emph>E</emph>,
+merge <emph>P</emph> into the specified style
+set of <emph>E</emph>, <emph>SSS(E)</emph>;</p></item>
+<item>
+<p><phrase role="strong">[implicit inheritance]</phrase> if the
+element type of <emph>E</emph> is not the styling element type
+<el>style</el>, then for each inheritable style property
+<emph>P<sub>INH</sub></emph> in the set of style properties defined
+above in <specref ref="styling-attribute-vocabulary"/>, perform the
+following ordered sub-steps:</p>
+<olist>
+<item><p>if <emph>P<sub>INH</sub></emph> is present in the specified
+style set of <emph>E</emph>, <emph>SSS(E)</emph>, then continue to the
+next inheritable style property;</p></item>
+<item><p>if the element type of <emph>E</emph> is the layout element
+type <el>region</el>, then set <emph>P&prime;</emph> to the initial value of
+property <emph>P</emph>, where the initial value of a property is
+determined according to the specific property definition found above
+in <specref ref="styling-attribute-vocabulary"/>;</p></item>
+<item><p>if the element type of <emph>E</emph> is a content element
+type or anonymous span, then set <emph>P&prime;</emph> to the result of
+looking up the value of <emph>P</emph> in the computed style set of
+the immediate ancestor element of <emph>E</emph>, i.e.,
+<emph>CSS(PARENT(E))</emph>;</p></item>
+<item><p>if the value of <emph>P&prime;</emph> is not undefined, then merge
+<emph>P&prime;</emph> into the specified style set of <emph>E</emph>,
+<emph>SSS(E)</emph>.</p></item>
+</olist>
+</item>
+</olist>
+</div4>
+<div4 id="semantics-style-resolution-processing-css">
+<head>Computed Style Set Processing</head>
+<p>The computed style set <emph>CSS</emph> of an element or
+anonymous span <emph>E</emph>,
+<emph>CSS(E)</emph>, is determined according to the following ordered
+rules:</p>
+<olist>
+<item><p><phrase role="strong">[resolve specified styles]</phrase>
+determine (obtain) the specified style set <emph>SSS</emph> of
+<emph>E</emph>, namely, <emph>SSS(E)</emph>, in accordance with
+<specref ref="semantics-style-resolution-processing-sss"/>;</p>
+</item>
+<item><p><phrase role="strong">[initialization]</phrase>
+initialize <emph>CSS(E)</emph> to a (deep) copy of
+<emph>SSS(E)</emph>;</p></item>
+<item><p><phrase role="strong">[filter]</phrase> if
+<emph>E</emph> is a <el>style</el> element, then return
+<emph>CSS(E)</emph> as the resulting computed style set without
+further resolution; otherwise, continue with the next rule;</p></item>
+<item>
+<p><phrase role="strong">[relative value resolution]</phrase> for each
+style property <emph>P</emph> in <emph>CSS(E)</emph>, where the value
+type of <emph>P</emph> is relative, perform the following ordered
+sub-steps:</p>
+<olist>
+<item><p>replace the relative value of <emph>P</emph> with an
+equivalent, non-relative (computed) value;</p></item>
+<item><p>set the category of <emph>P</emph> to "computed";</p></item>
+</olist>
+</item>
+</olist>
+<note role="explanation">
+<p>As a result of the filtering rule above, the computed style set of
+a <el>style</el> element includes only specified values, in which case
+relative value expressions remain relative; consequently, the
+resolution of relative value expressions (that may be assigned by
+means of referential style association) always takes place in the
+context of a layout or content element which has a presentation
+context, and not in the non-presentation, declaration context
+of a referentiable <el>style</el> element.</p>
+</note>
+</div4>
+<div4 id="semantics-style-resolution-process-overall">
+<head>Style Resolution Process</head>
+<p>The top-level style resolution process is defined as follows: using
+a preorder traversal of each element and anonymous span,
+<emph>E</emph>, of an intermediate synchronic document,
+<emph>DOC<sub>inter</sub></emph>, perform the following ordered
+sub-steps:</p>
+<olist>
+<item><p><phrase role="strong">[filter]</phrase> if the element type
+of <emph>E</emph> is not the styling element type <el>style</el>, is
+not the layout element type <el>region</el>, and is not one of the
+content element types <el>body</el>, <el>div</el>, <el>p</el>,
+<el>span</el>, <el>br</el>, or anonymous span, then continue to the
+next element in the preorder traversal;</p></item>
+<item><p> <phrase role="strong">[resolve computed styles]</phrase>
+determine (obtain) the computed style set <emph>CSS</emph> of
+<emph>E</emph>, namely, <emph>CSS(E)</emph>, in accordance with
+<specref ref="semantics-style-resolution-processing-css"/>.</p></item>
+</olist>
+</div4>
+</div3>
+</div2>
+</div1>
+<div1 id="layout">
+<head>Layout</head>
+<p>This section specifies the <emph>layout</emph> matter of the core
+vocabulary catalog, where
+layout is to be understood as a separable layer of information that applies to
+content and that denotes authorial intentions about the presentation of
+that content.</p>
+<note role="elaboration">
+<p>The two layers of layout and style matter are considered to be independently
+separable. Layout matter specifies one or more spaces or areas into
+which content is intended to be presented, while style matter specifies the manner in
+which presentation occurs within the layout.</p>
+<p>In certain cases, a content author may choose to embed (inline) style matter directly
+into layout or content matter. In such cases, an alternative 
+exists &ndash; use of referential styling &ndash;
+in which the style
+matter is not embedded (inlined).</p>
+</note>
+<div2 id="layout-element-vocabulary">
+<head>Layout Element Vocabulary</head>
+<p>The following elements specify the structure and principal layout aspects of a
+<emph>Document Instance</emph>:</p>
+<ulist>
+<item><p><specref ref="layout-vocabulary-layout"/></p></item>
+<item><p><specref ref="layout-vocabulary-region"/></p></item>
+</ulist>
+<div3 id="layout-vocabulary-layout">
+<head>layout</head>
+<p>The <el>layout</el> element is a container element used to group
+layout matter, including metadata that applies to layout matter.</p>
+<p>The <el>layout</el> element accepts as its children zero or more
+elements in the <code>Metadata.class</code> element group, followed by
+zero or more <el>region</el> elements.</p>
+<table id="elt-syntax-layout" role="syntax">
+<caption>XML Representation &ndash; Element Information Item: layout</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;layout
+  <loc href="#content-attribute-id">xml:id</loc> = ID
+  <loc href="#content-attribute-lang">xml:lang</loc> = string
+  <loc href="#content-attribute-space">xml:space</loc> = (<emph>default</emph>|<emph>preserve</emph>)
+  {<emph>any attribute not in default or any TT namespace</emph>}&gt;
+  <emph>Content:</emph> <loc href="#element-vocab-group-table">Metadata.class</loc>*, <loc href="#layout-vocabulary-region">region</loc>*
+&lt;/layout&gt;
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p>To the extent that time semantics apply to the content of the
+<el>layout</el> element, the implied time interval of this element is
+defined to be coterminous with the <emph>Root Temporal Extent</emph>.</p>
+</div3>
+<div3 id="layout-vocabulary-region">
+<head>region</head>
+<p>The <el>region</el> element is used to define a rectangular space or area into which content is
+to be flowed for the purpose of presentation.</p>
+<p>In addition, and in accordance with
+<specref ref="semantics-style-inheritance-region"/>, 
+the <el>region</el> element may be used to specify inheritable style properties to be
+inherited by content that is flowed into it.</p>
+<p>The <el>region</el> element accepts as its children zero or more
+elements in the <code>Metadata.class</code> element group,
+followed by zero or more
+elements in the <code>Animation.class</code> element group,
+followed by
+zero or more <el>style</el> elements.</p>
+<p>Any metadata specified by children in the <code>Metadata.class</code>
+element group applies semantically to the <el>region</el> element and its descendants as a whole.
+Any animation elements specified by children in the <code>Animation.class</code>
+element group apply semantically to the <el>region</el> element.
+Any <el>style</el> child element must be considered a local style
+definition that applies only to the containing <el>region</el>
+element, i.e., does not apply for resolving referential styling (but does apply for region
+style inheritance).</p>
+<table id="elt-syntax-region" role="syntax">
+<caption>XML Representation &ndash; Element Information Item: region</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;region
+  <loc href="#timing-attribute-begin">begin</loc> = <loc href="#timing-value-timeExpression">&lt;timeExpression&gt;</loc>
+  <loc href="#timing-attribute-dur">dur</loc> = <loc href="#timing-value-timeExpression">&lt;timeExpression&gt;</loc>
+  <loc href="#timing-attribute-end">end</loc> = <loc href="#timing-value-timeExpression">&lt;timeExpression&gt;</loc>
+  <loc href="#style-attribute-style">style</loc> = IDREFS
+  <loc href="#timing-attribute-timeContainer">timeContainer</loc> = (<emph>par</emph>|<emph>seq</emph>)
+  <loc href="#metadata-attribute-role">ttm:role</loc> = string
+  <loc href="#content-attribute-id">xml:id</loc> = ID
+  <loc href="#content-attribute-lang">xml:lang</loc> = string
+  <loc href="#content-attribute-space">xml:space</loc> = (<emph>default</emph>|<emph>preserve</emph>)
+  {<emph>any attribute in TT Style namespace</emph>}
+  {<emph>any attribute not in default or any TT namespace</emph>}&gt;
+  <emph>Content:</emph> <loc href="#element-vocab-group-table">Metadata.class</loc>*, <loc href="#element-vocab-group-table">Animation.class</loc>*, <loc href="#styling-vocabulary-style">style</loc>*
+&lt;/region&gt;
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p>If <att>begin</att> and (or) <att>end</att> attributes are specified on a
+<el>region</el> element, then they specify the beginning and (or) ending points
+of a time interval during which the region is eligible for activation and with
+respect to which animation child elements of the region are timed.
+If specified, these begin and end points are relative to the time
+interval of the nearest ancestor element associated with a time
+interval, irregardless of whether that interval is explicit or implied.</p>
+<p>The nearest ancestor element of a <el>region</el> element that is associated
+with a time interval is the <el>layout</el> element.</p>
+<p>If a <att>dur</att> attribute is specified on the <el>region</el> element, then it
+specifies the simple duration of the region.</p>
+<p>For the purpose of determining the semantics of presentation processing, a
+region that is temporally inactive must not produce any visible marks when
+presented on a visual medium.</p>
+<note role="motivation">
+<p>A <el>region</el> element may be associated with a time interval for two
+purposes: (1) in order to temporally bound the presentation of the region and
+its content, and (2) to provide a temporal context in which animations of region
+styles may be effected.</p>
+<p>For example, an author may wish to specify a region that is otherwise empty, but
+may have a visible background color to be presented starting at some time and
+continuing over the region's duration.  The simple duration of the region serves
+additionally to scope the presentation effects of content that is targeted to the
+region. An author may also wish to move a region within the <emph>Root Container Region</emph>
+or change a region's background color by means of animation effects. In
+both of these cases, it is necessary to posit an active time interval for a
+region.</p>
+</note>
+<p>If no <att>timeContainer</att> attribute is specified on
+a <el>region</el> element, then it must be interpreted as having
+<emph>parallel</emph> time containment semantics.</p>
+<p>If a <loc
+href="#metadata-attribute-role"><att>ttm:role</att></loc> attribute is
+specified on a <el>region</el> element, then it must adhere to the
+value syntax defined by <specref
+ref="metadata-attribute-role-syntax"/>, and where the roles identified
+by this attribute express the semantic roles of the region
+independently from the semantic roles of any content targeted to
+(associated with) the region.</p>
+</div3>
+</div2>
+<div2 id="layout-attribute-vocabulary">
+<head>Layout Attribute Vocabulary</head>
+<p>This section defines the <specref ref="layout-attribute-region"/> attribute used with content elements.</p>
+<div3 id="layout-attribute-region">
+<head>region</head>
+<p>The <att>region</att> attribute is used to reference a <el>region</el>
+element which defines a space or area into which a content element is intended to be flowed.</p>
+<p>If specified, the value of a <att>region</att> attribute must
+adhere to the <code>IDREF</code> data type defined by <bibref ref="xsd-2"/>,
+&sect; 3.3.9, and, furthermore, this IDREF must reference a <el>region</el> element
+which has a <el>layout</el> element as an ancestor.</p>
+<p>The <att>region</att> attribute may be specified by an instance of the following
+element types:</p>
+<ulist>
+<item><p><loc href="#document-structure-vocabulary-body"><el>body</el></loc></p></item>
+<item><p><loc href="#content-vocabulary-div"><el>div</el></loc></p></item>
+<item><p><loc href="#content-vocabulary-p"><el>p</el></loc></p></item>
+<item><p><loc href="#content-vocabulary-span"><el>span</el></loc></p></item>
+</ulist>
+<note role="seealso">
+<p>See <specref ref="semantics-region-layout"/> below for further information on content
+flow in a region.</p>
+</note>
+</div3>
+</div2>
+<div2 id="semantics-region-layout">
+<head>Region Layout and Presentation</head>
+<p>This section defines the semantics of region layout and
+presentation in terms of a standard processing model as
+follows:</p>
+<ulist>
+<item><p><specref ref="semantics-default-region"/></p></item>
+<item><p><specref ref="semantics-region-layout-step-1"/></p></item>
+<item><p><specref ref="semantics-region-layout-step-2"/></p></item>
+<item><p><specref ref="semantics-region-layout-example"/></p></item>
+</ulist>
+<p>Any
+implementation is permitted provided that the externally observable
+results are consistent with the results produced by this model.
+</p>
+<div3 id="semantics-default-region">
+<head>Default Region</head>
+<p>If a <emph>Document Instance</emph> does not specify a
+<loc href="#layout-vocabulary-region"><el>region</el></loc> element,
+then a <emph>default region</emph> is implied with the following characteristics:</p>
+<ulist>
+<item>
+<p>the identity of the default region is considered to be anonymous;</p>
+</item>
+<item>
+<p>the extent of the default region is the same as the extent of the <emph>Root Container Region</emph>;</p>
+</item>
+<item>
+<p>the temporal interval of the default region is the same as the interval defined by the <emph>Root Temporal Extent</emph>;</p>
+</item>
+</ulist>
+<p>Furthermore, if no <loc
+href="#layout-vocabulary-region"><el>region</el></loc> element is
+specified, then the <loc
+href="#layout-attribute-region"><att>region</att></loc> attribute must
+not be specified on any content element in the <emph>Document Instance</emph>.</p>
+<p>If a default region is implied for a given <emph>Document Instance</emph>, then
+the <loc href="#document-structure-vocabulary-body"><el>body</el></loc> element
+is implicitly targeted to (associated with) the default region.</p>
+<p>When implying a default region, the <emph>Document Instance</emph> is to be
+treated as if a <loc
+href="#layout-vocabulary-region"><el>region</el></loc> element and its
+parent <loc href="#layout-vocabulary-layout"><el>layout</el></loc>
+element were specified in a <loc
+href="#document-structure-vocabulary-head"><el>head</el></loc>
+element, and a matching <loc
+href="#layout-attribute-region"><att>region</att></loc> attribute were
+specified on the <loc
+href="#document-structure-vocabulary-body"><el>body</el></loc> element
+as shown in the following example:</p>
+<table id="semantics-default-region-example" role="example">
+<caption>Example &ndash; Implied Default Region</caption>
+<tbody>
+<tr>
+<td>
+<eg>
+&lt;tt xml:lang="" xmlns="http://www.w3.org/ns/ttml"&gt;
+  &lt;head&gt;
+    <phrase role="strong">&lt;layout&gt;
+      &lt;region xml:id="anonymous"/&gt;
+    &lt;/layout&gt;</phrase>
+  &lt;/head&gt;
+  &lt;body <phrase role="strong">region="anonymous"</phrase>/&gt;
+&lt;/tt&gt;
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<note role="explanation">
+<p>In the above example, a default <el>region</el> element and <att>region</att>
+attribute are implied. In addition, a <el>layout</el> container element is implied for
+the implied <el>region</el> element.</p>
+</note>
+</div3>
+<div3 id="semantics-region-layout-step-1">
+<head>Intermediate Synchronic Document Construction</head>
+<p>For the purposes of performing presentation processing, the active time
+duration of a <emph>Document Instance</emph> is divided into a sequence of time coordinates where at
+each time coordinate, some element becomes temporally active or inactive,
+then, at each such time coordinate, a <emph>Document Instance</emph> is mapped from its original, source
+form, <emph>DOC<sub>source</sub></emph>&thinsp;, 
+to an intermediate
+synchronic document form,
+<emph>DOC<sub>inter</sub></emph>&thinsp;, according to the
+<phrase role="strong">[construct intermediate document]</phrase> procedure:</p>
+<glist>
+<gitem>
+<label>[construct intermediate document]</label>
+<def>
+<olist>
+<item>
+<p>for each temporally active region <emph>R</emph>, replicate the
+sub-tree
+ of <emph>DOC<sub>source</sub></emph>
+headed by the <el>body</el> element;</p>
+</item>
+<item>
+<p>evaluating this sub-tree in a postorder traversal, prune elements if they
+are not a content element, if they are temporally inactive, if they are empty,
+or if they aren't associated with region <emph>R</emph> according to the
+<phrase role="strong">[associate region]</phrase> procedure;</p>
+</item>
+<item>
+<p>if the pruned sub-tree is non-empty, then reparent it to the <emph>R</emph>
+element;</p>
+</item>
+<item>
+<p>finally, after completing the above steps, prune the original <el>body</el>
+element from the intermediate document, then prune all <att>region</att>,
+<att>begin</att>, <att>end</att>, and <att>dur</att> attributes, which are no
+longer semantically relevant;</p>
+</item>
+</olist>
+<note role="elaboration">
+<p>In this section, the term <emph>prune</emph>, when used in reference to
+an element, means that the element is to be removed from its parent's children,
+which, in turn, implies that the descendants of the pruned element will no longer
+be descendants of the element's parent. When <emph>prune</emph> is used in
+reference to an attribute, it means that attribute is to be removed from its
+associated (owning) element node.</p>
+</note>
+</def>
+</gitem>
+<gitem>
+<label>[associate region]</label>
+<def>
+<p>A content element is associated with a region according
+to the following ordered rules, where the first rule satisfied
+is used and remaining rules are skipped:</p>
+<olist>
+<item><p>if the element specifies a <loc
+href="#layout-attribute-region"><att>region</att></loc> attribute,
+then the element is associated with the region referenced by that
+attribute;</p></item>
+<item><p>if some ancestor of that element specifies a <loc
+href="#layout-attribute-region"><att>region</att></loc> attribute,
+then the element is associated with the region referenced by the most
+immediate ancestor that specifies this attribute;</p></item>
+<item><p> if the element contains a descendant element that
+specifies a <loc
+href="#layout-attribute-region"><att>region</att></loc> attribute,
+then the element is associated with the region referenced by that
+attribute;</p></item>
+<item><p>if a default region was implied (due to the absence of any
+<loc href="#layout-vocabulary-region"><el>region</el></loc> element),
+then the element is associated with the default region;</p></item>
+<item><p>the element is not associated with any region.</p></item>
+</olist>
+</def>
+</gitem>
+</glist>
+<p>The result of performing the processing described above will be a sequence of
+<emph>N</emph> intermediate  synchronic
+<emph>Document Instances</emph>,
+<emph>DOC<sub><phrase>inter<sub>0</sub></phrase></sub></emph> &hellip;
+<emph>DOC<sub><phrase>inter<sub>N&minus;1</sub></phrase></sub></emph>.</p>
+<note id="semantics-smooth-scrolling-recommendation" role="elaboration">
+<p>Where an implementation is able to detect significant similarity between two
+adjacent synchronic <emph>Document Instances</emph>,
+<emph>DOC<sub><phrase>inter<sub>N</sub></phrase></sub></emph>
+<emph>DOC<sub><phrase>inter<sub>N&minus;1</sub></phrase></sub></emph>,
+then it is preferred that the implementation make the transition between
+presenting the two instances as smooth as possible, e.g., as described
+by <bibref ref="cea608c"/>, &sect; C.3.</p>
+</note>
+</div3>
+<div3 id="semantics-region-layout-step-2">
+<head>Synchronic Flow Processing</head>
+<p>Subsequent to performing a temporal (synchronic) slice and subsequent
+remapping of regionally selected content hierarchy, the resulting intermediate
+synchronic document is subjected to a flow transformation step that produces 
+a rooted flow object tree represented as an XSL FO document instance as defined by <bibref ref="xsl11"/>,
+and semantically extended by TTML specific style properties that have no XSL
+FO counterpart.</p>
+<note>
+<p>In this section, the use of XSL FO is intended to be conceptual only, employed
+solely for the purpose of defining the normative presentation semantics of
+TTML. An actual implementation of this algorithm is not required to create or process
+XSL-FO representations. In particular, it is possible to implement these semantics
+using alternative presentation models, such as Cascading Style Sheets (CSS).</p>
+</note>
+<p>Each intermediate synchronic document produced by <specref
+ref="semantics-region-layout-step-1"/> is mapped 
+to an XSL FO document instance, <emph>F</emph>, as follows:</p>
+<olist>
+<item>
+<p>perform the following ordered sub-steps to create anonymous spans:</p>
+<olist>
+<item><p>for each significant text node in a content element,
+synthesize an anonymous span to enclose the text node, substituting
+the new anonymous span for the original text node child in its sibling
+and parent hierarchy;</p></item>
+<item><p>for each contiguous sequence of anonymous spans, replace the
+sequence with a single anonymous span which contains a sequence of
+text nodes representing the individual text node children of the
+original sequence of anonymous spans;</p></item>
+<item><p>for each span element whose child is a single anonymous span,
+replace the anonymous span with its sequence of child text
+nodes;</p></item>
+</olist>
+</item>
+<item>
+<p>resolve styles according to <specref
+ref="semantics-style-resolution-process-overall"/>;</p>
+</item>
+<item>
+<p>map the <el>tt</el> element to an <el>fo:root</el> element, populated
+initially with an <el>fo:layout-master-set</el> element that contains a valid
+<el>fo:simple-page-master</el> that, in turn, contains an
+<el>fo:region-body</el> child, where the extent of the <emph>Root Container Region</emph> expressed on the
+<el>tt</el> element is mapped to <att>page-width</att> and
+<att>page-height</att> attributes on the <el>fo:simple-page-master</el>
+element;</p>
+</item>
+<item>
+<p>map the <el>layout</el> element to an <el>fo:page-sequence</el> element and a
+child <el>fo:flow</el> element that reference the page master and page region
+defined by the simple page master produced above;</p>
+</item>
+<item>
+<p>map each non-empty <el>region</el> element to an <el>fo:block-container</el>
+element with an <att>absolute-position</att> attribute with value
+<code>absolute</code>, with <att>top</att>, <att>left</att>, <att>bottom</att>, and <att>right</att>
+attributes that express a rectangle equivalent to the region's origin and
+extent, and with a <att>line-stacking-strategy</att> attribute with value <code>line-height</code>;</p>
+</item>
+<item>
+<p>for each <el>body</el>, <el>div</el>, and <el>p</el> element that is not
+associated with a <att>tts:display</att> style property with the value
+<code>none</code>, map the element to a distinct <el>fo:block</el> element,
+populating the style properties of <el>fo:block</el> by using the computed
+style set associated with each original TTML Content element;</p>
+</item>
+<item>
+<p>for the resulting <el>fo:block</el> formatting object
+produced in the previous step that corresponds to the <el>body</el>
+element, perform the following ordered sub-steps:</p>
+<olist>
+<item>
+<p>if the <att>display-align</att> style property of this <el>fo:block</el>
+has the value <code>center</code> or <code>after</code>,
+then synthesize and insert as the first child of this <el>fo:block</el>
+an empty <el>fo:block</el> with the following attributes:
+<att>space-after.optimum</att>, <att>space-after.maximum</att>, and
+<att>space-after.conditionality</att>, where the value of the former
+two attributes is the height or width of the containing
+<el>fo:block-container</el> element, whichever of these is designated
+as the block progression dimension, and where the value of the last is
+<code>retain</code>;</p>
+</item>
+<item>
+<p>if the <att>display-align</att> style property of this <el>fo:block</el>
+has the value <code>center</code> or <code>before</code>,
+then synthesize and insert as the last child of this <el>fo:block</el>
+an empty <el>fo:block</el> with the following attributes:
+<att>space-after.optimum</att>, <att>space-after.maximum</att>, and
+<att>space-after.conditionality</att>, where the value of the former
+two attributes is the height or width of the containing
+<el>fo:block-container</el> element, whichever of these is designated
+as the block progression dimension, and where the value of the last is
+<code>retain</code>;</p>
+</item>
+</olist>
+</item>
+<item>
+<p>for each <el>span</el> element that is not
+associated with a <att>tts:display</att> style property with the value
+<code>none</code> and for each anonymous
+span that is a child of a <el>p</el> or <el>span</el> element,
+map the element or
+sequence of character items to a distinct <el>fo:inline</el> element,
+populating the style properties of <el>fo:inline</el> by using the computed
+style set associated with each original TTML Content element
+or anonymous span;</p>
+</item>
+<item>
+<p>for each <el>br</el> element that is not
+associated with a <att>tts:display</att> style property with the value
+<code>none</code>, map the element to
+a distinct <el>fo:character</el> element having the following
+properties:</p>
+<ulist>
+<item>
+<p><code>character="&amp;#x000A;"</code></p>
+</item>
+<item>
+<p><code>suppress-at-line-break="retain"</code></p>
+</item>
+</ulist>
+</item>
+<item>
+<p>for each TTML style property attribute in some computed
+style set that
+has no counterpart in <bibref ref="xsl11"/>, map that attribute directly through
+to the relevant formatting object produced by the input TTML Content element to
+which the style property applies;</p>
+</item>
+<item>
+<p>optionally, synthesize a unique <att>id</att> attribute on each resulting
+formatting object element that relates that element to the input element that
+resulted in that formatting object element;</p>
+</item>
+</olist>
+<p>For each resulting document instance F, if processing requires presentation on a 
+visual medium, then apply formatting and rendering semantics consistent with that 
+prescribed by <bibref ref="xsl11"/>.</p>
+<note role="elaboration">
+<p>In an XSL FO area tree produced by formatting <emph>F</emph> using 
+an <bibref ref="xsl11"/> formatting processor, 
+the <code>page-viewport-area</code>,
+which is generated by <code>fo:page-sequence</code> element by
+reference to the sole generated <code>fo:simple-page-master</code>
+element, would correspond to the <emph>Root Container Region</emph> defined
+above in <specref ref="definitions"/>.</p>
+</note>
+<note>
+<p>Due to the possible presence of TTML style properties or style property values
+in a given <emph>Document Instance</emph> for which there is no <bibref ref="xsl11"/> counterpart,
+Implementors should recognize that it is the layout model of <bibref ref="xsl11"/> that is being referenced
+by this specification, not the requirement to use a compliant <bibref ref="xsl11"/> formatting processor,
+since such would not necessarily be sufficient to satisfy the full presentation semantics
+defined by this specification, and would contain a large number of features not needed to
+implement the presentation semantics of TTML.</p>
+</note>
+<note role="explanation">
+<p>The purpose of inserting additional, collapsible space in the block progression
+dimension of the <el>fo:block</el> that corresponds with the <el>body</el> element
+is to ensure that the before and after edges of this <el>fo:block</el> are coincident
+with the before and after edges of the <el>fo:block-container</el> that corresponds
+to the containing <el>region</el>, while simultaneously taking into account the needs
+to satisfy alignment in the block progression dimension. For example, this assures that
+the background color associated with the <el>body</el> element, if not <code>transparent</code>,
+ will fill the containing region wholly.</p>
+</note>
+</div3>
+<div3 id="semantics-region-layout-example">
+<head>Elaborated Example (Informative)</head>
+<p>An example of the processing steps described above is elaborated below, starting with <specref
+ref="region-mapping-example-1-s"/>.</p>
+<table id="region-mapping-example-1-s" role="example">
+<caption>Example &ndash; Sample Source Document</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">&ttml-ex1;</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p>In the above document, the content hierarchy consists of two divisions, each
+containing two paragraphs. This content is targeted (associated with) one of two
+non-overlapping regions that are styled identically except for their position
+and their foreground colors, the latter of which is inherited by and applies to
+the (and, in this case, anonymous) spans reparented into the regions.</p>
+<p>The following, first intermediate document shows the synchronic state for time
+interval [0,1), during which time only division <code>d1</code> is temporally active,
+and where paragraphs <code>p1</code> and <code>p2</code> (and their ancestors)
+are associated with regions <code>r1</code> and <code>r2</code>, respectively.</p>
+<note>
+<p>The intermediate documents shown below are not valid <emph>Document Instances</emph>,
+but rather, are representations of possible internal processing states used for
+didactic purposes.</p>
+</note>
+<table id="region-mapping-example-1-i0" role="example">
+<caption>Example &ndash; Intermediate Document &ndash; [0s,1s)</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">&ttml-ex1-x-0;</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p>An XSL FO document instance that would yield rendering consistent with TTML, and 
+which may be produced by performing flow processing upon the first intermediate 
+document is illustrated below.</p>
+<table id="region-mapping-example-1-f0" role="example">
+<caption>Example &ndash; XSL FO Document &ndash; [0s,1s)</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">&ttml-ex1-p-0;</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p>The following, second intermediate document shows the synchronic state for
+time interval [1,2), during which time both divisions <code>d1</code> and
+<code>d2</code> are temporally active, and where paragraphs <code>p1</code> and
+<code>p4</code> (and their ancestors) are associated with region <code>r1</code>
+and paragraphs <code>p2</code> and <code>p3</code> (and their ancestors) are
+associated with region <code>r2</code>.</p>
+<table id="region-mapping-example-1-i1" role="example">
+<caption>Example &ndash; Intermediate Document &ndash; [1s,2s)</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">&ttml-ex1-x-1;</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p>The following, third intermediate document shows the synchronic state for time
+interval [2,3), during which time only division <code>d2</code> is temporally active,
+and where paragraphs <code>p4</code> and <code>p3</code> (and their ancestors)
+are associated with regions <code>r1</code> and <code>r2</code>, respectively.</p>
+<table id="region-mapping-example-1-i2" role="example">
+<caption>Example &ndash; Intermediate Document &ndash; [2s,3s)</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">&ttml-ex1-x-2;</eg>
+</td>
+</tr>
+</tbody>
+</table>
+</div3>
+</div2>
+<div2 id="semantics-line-layout">
+<head>Line Layout</head>
+<p>If a profile that applies to a <emph>Document Instance</emph>
+requires use of the <loc
+href="#feature-lineBreak-uax14">#lineBreak-uax14</loc> feature
+(i.e., the value attribute for the feature is specified as <code>use</code>), then
+the recommendations defined by <loc
+href="http://www.unicode.org/reports/tr14/#Algorithm">Line
+Breaking Algorithm</loc> <bibref ref="uax14"/> apply when performing
+line layout on the content of the <emph>Document Instance</emph>.</p>
+</div2>
+</div1>
+<div1 id="timing">
+<head>Timing</head>
+<p>This section specifies the <emph>timing</emph> matter of the core
+vocabulary catalog, where
+timing is to be understood as a separable layer of information that applies to
+content and that denotes authorial intentions about the temporal presentation of
+that content.</p>
+<div2 id="timing-element-vocabulary">
+<head>Timing Element Vocabulary</head>
+<p>No timing related element vocabulary is defined for use in the core
+vocabulary catalog.</p>
+</div2>
+<div2 id="timing-attribute-vocabulary">
+<head>Timing Attribute Vocabulary</head>
+<p>This section defines the following basic timing attributes for use with timed elements:</p>
+<ulist>
+<item><p><specref ref="timing-attribute-begin"/></p></item>
+<item><p><specref ref="timing-attribute-end"/></p></item>
+<item><p><specref ref="timing-attribute-dur"/></p></item>
+</ulist>
+<p>In addition, this section defines the <specref
+ref="timing-attribute-timeContainer"/> attribute for use with timed elements
+that serve simultaneously as timing containers.</p>
+<div3 id="timing-attribute-begin">
+<head>begin</head>
+<p>The <att>begin</att> attribute is used to specify the begin
+point of a temporal interval associated with a timed element. If
+specified, the value of a <att>begin</att> attribute must adhere to
+a &lt;timeExpression&gt; specification as defined by <specref
+ref="timing-value-timeExpression"/>.</p>
+<p>The begin point of a temporal interval is included in the
+interval; i.e., the interval is left-wise closed.</p>
+<p>The semantics of the <att>begin</att> attribute are those defined
+by <bibref ref="smil21"/>, &sect; 10.4.1,
+while taking into account any overriding semantics defined by this specification.</p>
+</div3>
+<div3 id="timing-attribute-end">
+<head>end</head>
+<p>The <att>end</att> attribute is used to specify the ending point
+of a temporal interval associated with a timed element. If
+specified, the value of an <att>end</att> attribute must adhere to a
+&lt;timeExpression&gt; specification as defined by <specref
+ref="timing-value-timeExpression"/>.</p>
+<p>The ending point of a temporal interval is not included in the
+interval; i.e., the interval is right-wise open.</p>
+<p>The presentation effects of a non-empty active
+temporal interval include the frame immediately prior to the frame
+(or tick) equal to or immediately following the time specified by the ending
+point, but do not extend into this latter frame (or tick).</p>
+<note role="example">
+<p>For example, if an active interval is [10s,10.33333s), and the
+frame rate is 30 frames per second, then the presentation effects of the interval
+are limited to frames 300 through 309 only (assuming that 0s corresponds
+with frame 0). The same holds if the active interval is specified
+as [300f,310f).</p>
+</note>
+<p>The semantics of the <att>end</att> attribute are those defined
+by <bibref ref="smil21"/>, &sect; 10.4.1,
+while taking into account any overriding semantics defined by this specification.</p>
+</div3>
+<div3 id="timing-attribute-dur">
+<head>dur</head>
+<p>The <att>dur</att> attribute is used to specify the duration of a
+temporal interval associated with a timed element. If specified,
+the value of a <att>dur</att> attribute must adhere to a
+&lt;timeExpression&gt; specification as defined by <specref
+ref="timing-value-timeExpression"/>.</p>
+<note role="clarification">
+<p>When the <code>clock-time</code> form of a &lt;timeExpression&gt; specification
+is used with a <att>dur</att> attribute, it is intended to be interpreted as
+a difference between two implied clock time expressions.</p>
+</note>
+<p>When a <emph>Document Instance</emph> specifies the use of the
+<code>smpte</code> time base and <code>discontinuous</code> marker
+mode, a (well-formed) <att>dur</att> attribute must not be specified on any
+element.</p>
+<p>The semantics of the <att>dur</att> attribute are those defined
+by <bibref ref="smil21"/>, &sect; 10.4.1,
+while taking into account any overriding semantics defined by this specification.</p>
+<note role="elaboration">
+<p>In the context of the subset of <bibref ref="smil21"/> semantics supported by
+this specification, the active duration of an element that specifies both
+<att>end</att> and <att>dur</att> attributes is equal to the lesser of the value of
+the <att>dur</att> attribute and the difference between the value of the
+<att>end</att> attribute and the element's begin time.</p>
+</note>
+</div3>
+<div3 id="timing-attribute-timeContainer">
+<head>timeContainer</head>
+<p>The <att>timeContainer</att> attribute is used to specify a local temporal
+context by means of which timed child elements are temporally situated.</p>
+<p>If specified, the value of a <att>timeContainer</att> attribute must be one
+of the following:</p>
+<ulist>
+<item><p><code>par</code></p></item>
+<item><p><code>seq</code></p></item>
+</ulist>
+<p>If the time container semantics of an element instance is <code>par</code>,
+then the temporal intervals of child elements are considered to apply in
+parallel, i.e., simultaneously in time. Furthermore, the specification of
+the time interval of each child element is considered to be relative to the temporal
+interval of the container element instance. For the purpose of determining the
+<bibref ref="smil21"/> <code>endsync</code> semantics of a <code>par</code>
+time container, a default value of <code>all</code> applies.</p>
+<note role="elaboration">
+<p>The use of a default value of <code>all</code> for the <code>endsync</code>
+behavior is distinct from <bibref ref="smil21"/> which uses a default value
+of <code>last</code>.</p>
+</note>
+<p>If the time container semantics of an element instance is <code>seq</code>,
+then the temporal intervals of child elements are considered to apply in
+sequence, i.e., sequentially in time. Furthermore, the specification of
+the time interval of each child element is considered to be relative to the temporal
+interval of its sibling elements, unless it is the first child element, in which case
+it is considered to be relative to the temporal interval of the container
+element instance.</p>
+<p>Each time container is considered to constitute an independent time base, i.e.,
+time coordinate system.</p>
+<p>If a <att>timeContainer</att> attribute is not specified on an element that
+has time container semantics, then <code>par</code> time container semantics must apply.</p>
+<p>Time container semantics applies only to the following element types:</p>
+<ulist>
+<item><p><loc href="#document-structure-vocabulary-body"><el>body</el></loc></p></item>
+<item><p><loc href="#content-vocabulary-div"><el>div</el></loc></p></item>
+<item><p><loc href="#content-vocabulary-p"><el>p</el></loc></p></item>
+<item><p><loc href="#layout-vocabulary-region"><el>region</el></loc></p></item>
+<item><p><loc href="#content-vocabulary-span"><el>span</el></loc></p></item>
+</ulist>
+<p>The semantics of parallel and sequential time
+containment are those defined by <bibref ref="smil21"/>, &sect; 10.4.2,
+while taking into account any overriding semantics defined by this specification.</p>
+</div3>
+</div2>
+<div2 id="timing-time-value-expressions">
+<head>Time Value Expressions</head>
+<p>Timing attribute values include the use of the following expressions:</p>
+<ulist>
+<item><p><specref ref="timing-value-timeExpression"/></p></item>
+</ulist>
+<div3 id="timing-value-timeExpression">
+<head>&lt;timeExpression&gt;</head>
+<p>A &lt;timeExpression&gt; is used to specify a coordinate within
+some time base, where the applicable time base is determined by the
+<att>ttp:timeBase</att> parameter, and where the semantics defined
+by <specref ref="time-expression-semantics"/> apply.</p>
+
+<note role="example">
+<p>See
+<specref ref="parameter-attribute-frameRate"/>,
+<specref ref="parameter-attribute-subFrameRate"/>,
+<specref ref="parameter-attribute-tickRate"/>, and
+<specref ref="parameter-attribute-timeBase"/> for further information on
+explicit specification of frame rate, sub-frame rate, tick rate, and time base.</p>
+</note>
+<table id="timeExpression-syntax" role="syntax">
+<caption>Syntax Representation &ndash; &lt;timeExpression&gt;</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;timeExpression&gt;
+  : clock-time
+  | offset-time
+
+clock-time
+  : hours ":" minutes ":" seconds ( fraction | ":" frames ( "." sub-frames )? )?
+
+offset-time
+  : time-count fraction? metric
+
+hours
+  : <loc href="#style-value-digit">&lt;digit&gt;</loc> <loc href="#style-value-digit">&lt;digit&gt;</loc>
+  | <loc href="#style-value-digit">&lt;digit&gt;</loc> <loc href="#style-value-digit">&lt;digit&gt;</loc> <loc href="#style-value-digit">&lt;digit&gt;</loc>+
+
+minutes | seconds
+  : <loc href="#style-value-digit">&lt;digit&gt;</loc> <loc href="#style-value-digit">&lt;digit&gt;</loc>
+
+frames
+  : <loc href="#style-value-digit">&lt;digit&gt;</loc> <loc href="#style-value-digit">&lt;digit&gt;</loc>
+  | <loc href="#style-value-digit">&lt;digit&gt;</loc> <loc href="#style-value-digit">&lt;digit&gt;</loc> <loc href="#style-value-digit">&lt;digit&gt;</loc>+
+
+sub-frames
+  : <loc href="#style-value-digit">&lt;digit&gt;</loc>+
+
+fraction
+  : "." <loc href="#style-value-digit">&lt;digit&gt;</loc>+
+
+time-count
+  : <loc href="#style-value-digit">&lt;digit&gt;</loc>+
+
+metric
+  : "h"                 // hours
+  | "m"                 // minutes
+  | "s"                 // seconds
+  | "ms"                // milliseconds
+  | "f"                 // frames
+  | "t"                 // ticks
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p>If a &lt;timeExpression&gt; is expressed in terms of a
+<emph>clock-time</emph>, then leading zeroes are used when expressing hours,
+minutes, seconds, and frames less than 10. Minutes are constrained to
+[0&hellip;59], while seconds (including any fractional part) are constrained to the closed
+interval [0,60], where the value 60 applies only to leap seconds.</p>
+<p>If a &lt;timeExpression&gt; is expressed in terms of a
+<emph>clock-time</emph> and a <emph>frames</emph> term is specified,
+then the value of this term must be constrained to the interval
+[0&hellip;<emph>F-1</emph>], where <emph>F</emph> is the frame rate
+determined by the <att>ttp:frameRate</att> parameter as defined
+by <specref ref="parameter-attribute-frameRate"/>.
+It is considered an error if a <emph>frames</emph> term or
+<code>f</code> (frames) metric is specified when the <code>clock</code> time base applies.</p>
+<p>If a &lt;timeExpression&gt; is expressed in terms of a
+<emph>clock-time</emph> and a <emph>sub-frames</emph> term is
+specified, then the value of this term must be constrained to the
+interval [0&hellip;<emph>S-1</emph>], where <emph>S</emph> is the
+sub-frame rate determined by the <att>ttp:subFrameRate</att> parameter as defined by <specref
+ref="parameter-attribute-subFrameRate"/>.
+It is considered an error if a <emph>sub-frames</emph> term is specified
+when the <code>clock</code> time base applies.</p>
+</div3>
+</div2>
+<div2 id="timing-time-intervals">
+<head>Time Intervals</head>
+<p>The semantics of time containment, durations, and intervals defined by
+<bibref ref="smil21"/> apply to the interpretation of like-named timed elements and timing
+vocabulary defined by this specification, given the following
+constraints:</p>
+<ulist>
+<item>
+<p>The implicit duration of an anonymous span is defined as follows: if
+the anonymous span's parent time container is a parallel time container, then
+the implicit duration is equivalent to the <code>indefinite</code>
+duration value as defined by <bibref ref="smil21"/>; if the anonymous span's
+parent time container is a sequential time container, then the implicit duration
+is equivalent to zero.</p>
+</item>
+<item>
+<p>The implicit duration of a <el>body</el>, <el>div</el>, <el>p</el>,
+or <el>span</el> element is determined in accordance to (1) whether
+the element is a parallel or sequential time container, (2) the default
+<code>endsync</code> semantics defined above by <specref ref="timing-attribute-timeContainer"/>,
+and (3) the semantics of <bibref ref="smil21"/> as applied to these time
+containers.</p>
+</item>
+<item>
+<p>The implicit duration of the <el>region</el> element is defined to
+be equivalent to the <code>indefinite</code>
+duration value as defined by <bibref ref="smil21"/>.</p>
+</item>
+<item>
+<p>If the governing time base is <code>clock</code>, then time
+expressions are considered to be equivalent to wall-clock
+based timing in <bibref ref="smil21"/>, where the specific semantics of
+<specref ref="time-expression-semantics-clock"/> apply.</p>
+</item>
+<item>
+<p>If the governing time base is <code>media</code>, then time
+expressions are considered to be equivalent to offset based timing
+in <bibref ref="smil21"/>, where the specific semantics of
+<specref ref="time-expression-semantics-media"/> apply.</p>
+</item>
+<item>
+<p>If the governing time base is <code>smpte</code>, then time
+expressions are considered to be equivalent to either offset
+based timing or event based timing in <bibref ref="smil21"/>, where the specific semantics of
+<specref ref="time-expression-semantics-smpte"/> apply.</p>
+</item>
+</ulist>
+</div2>
+</div1>
+<div1 id="animation">
+<head>Animation</head>
+<p>This section specifies the <emph>animation</emph> matter of the
+core vocabulary catalog, where
+animation is to be understood as a separable layer of information that combines
+timing and styling in order to denote authorial intention about (temporally) dynamic
+styling of content.</p>
+<div2 id="animation-element-vocabulary">
+<head>Animation Element Vocabulary</head>
+<p>The following elements specify the structure and principal animation aspects of a
+<emph>Document Instance</emph>:</p>
+<ulist>
+<item><p><specref ref="animation-vocabulary-set"/></p></item>
+</ulist>
+<div3 id="animation-vocabulary-set">
+<head>set</head>
+<p>The <el>set</el> element is used as a child element of a content
+element or a <el>region</el> element
+in order to express a discrete change of some style parameter value
+that applies over some time interval.</p>
+<p>The <el>set</el> element accepts as its children zero or more
+elements in the <code>Metadata.class</code> element group.</p>
+<table id="elt-syntax-set" role="syntax">
+<caption>XML Representation &ndash; Element Information Item: set</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;set
+  <loc href="#timing-attribute-begin">begin</loc> = <loc href="#timing-value-timeExpression">&lt;timeExpression&gt;</loc>
+  <loc href="#timing-attribute-dur">dur</loc> = <loc href="#timing-value-timeExpression">&lt;timeExpression&gt;</loc>
+  <loc href="#timing-attribute-end">end</loc> = <loc href="#timing-value-timeExpression">&lt;timeExpression&gt;</loc>
+  <loc href="#content-attribute-id">xml:id</loc> = ID
+  <loc href="#content-attribute-lang">xml:lang</loc> = string
+  <loc href="#content-attribute-space">xml:space</loc> = (<emph>default</emph>|<emph>preserve</emph>)
+  {<emph>a single attribute in TT Style namespace</emph>}
+  {<emph>any attribute not in default or any TT namespace</emph>}&gt;
+  <emph>Content:</emph> <loc href="#element-vocab-group-table">Metadata.class</loc>*
+&lt;/set&gt;
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<note role="example">
+<p>The use of multiple <el>set</el> element children may be used to effect fade and
+position transitions.</p>
+</note>
+<p>An example of using the <el>set</el> element to animate content
+styling is illustrated below:</p>
+<table id="animation-vocabulary-set-example-1" role="example">
+<caption>Example Fragment &ndash; Content Style Animation</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+...
+&lt;p dur="5s" tts:color="yellow"&gt;
+<phrase role="strong">&lt;set begin="1s" dur="1s" tts:color="red"/&gt;</phrase>
+<phrase role="strong">&lt;set begin="2s" dur="1s" tts:color="green"/&gt;</phrase>
+<phrase role="strong">&lt;set begin="3s" dur="1s" tts:color="red"/&gt;</phrase>
+Text with Flashing Colors!
+&lt;/p&gt;
+...
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<note role="explanation">
+<p>In the above example, the foreground color of the content "Text
+with Flashing Colors" is animated from yellow, to red, to green, to
+red, then back to yellow over a 5 second period.</p>
+</note>
+
+<p>An example of using the <el>set</el> element to animate region
+styling is illustrated below:</p>
+<table id="animation-vocabulary-set-example-2" role="example">
+<caption>Example Fragment &ndash; Region Style Animation</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;tt xml:lang="" xmlns="http://www.w3.org/ns/ttml"
+    xmlns:ttp="http://www.w3.org/ns/ttml#parameter"
+    xmlns:tts="http://www.w3.org/ns/ttml#styling"
+    ttp:cellResolution="40 16"&gt;
+    &lt;head&gt;
+      &lt;layout&gt;
+	&lt;region xml:id="r1" timeContainer="seq"&gt;
+	  <phrase role="strong">&lt;set dur="10s" tts:origin=" 8c 14c"/&gt;</phrase>
+	  <phrase role="strong">&lt;set dur="2s"  tts:origin=" 2c  2c"/&gt;</phrase>
+	  <phrase role="strong">&lt;set dur="3s"  tts:origin=" 8c 14c"/&gt;</phrase>
+	  <phrase role="strong">&lt;set dur="2s"  tts:origin="14c  4c"/&gt;</phrase>
+	  <phrase role="strong">&lt;set dur="10s" tts:origin=" 8c 14c"/&gt;</phrase>
+	  &lt;style tts:extent="24c 2c"/&gt;
+	&lt;/region&gt;
+      &lt;/layout&gt;
+    &lt;/head&gt;
+    &lt;body region="r1"&gt;...&lt;/body&gt;
+&lt;/tt&gt;
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<note role="explanation">
+<p>In the above example, the <emph>Root Container Region</emph> is divided into a
+cell grid of 40 columns and 16 rows. A region, <code>r1</code>, with
+dimensions of 24 columns and 2 rows is then positioned within the
+<emph>Root Container Region</emph>, with its position varying over time in order to
+create an effect of moving the region, which may be desirable so as
+to avoid obscuring characters in an underlying video with captions.</p>
+</note>
+<note role="derivation">
+<p>The semantics of the <el>set</el> element
+are based upon that defined by <bibref ref="smil21"/>,
+&sect; 3.6.2.</p>
+</note>
+</div3>
+</div2>
+<div2 id="animation-attribute-vocabulary">
+<head>Animation Attribute Vocabulary</head>
+<p>No animation related attribute vocabulary is defined for use in the
+core vocabulary catalog.</p>
+</div2>
+</div1>
+<div1 id="metadata">
+<head>Metadata</head>
+<p>This section specifies the <emph>metadata</emph> matter of the core
+vocabulary catalog, where
+metadata is to be understood as a separable layer of information that applies to
+parameters, content,
+style, layout, timing, and even metadata itself, where the information
+represented by metadata takes one of two forms: (1) metadata defined by this
+specification for standardized use in a <emph>Document Instance</emph>, and (2) arbitrary
+metadata defined outside of the scope of this specification, whose use and
+semantics depend entirely upon an application's use of TTML Content.</p>
+<div2 id="metadata-element-vocabulary">
+<head>Metadata Element Vocabulary</head>
+<p>The <specref ref="metadata-vocabulary-metadata"/> element serves as
+a generic container element for grouping metadata information.</p>
+<p>In addition, the following elements, all defined in the TT Metadata Namespace,
+provide standard representations for metadata that is expected to be commonly
+used in a <emph>Document Instances</emph>:
+</p>
+<ulist>
+<item><p><specref ref="metadata-vocabulary-title"/></p></item>
+<item><p><specref ref="metadata-vocabulary-desc"/></p></item>
+<item><p><specref ref="metadata-vocabulary-copyright"/></p></item>
+<item><p><specref ref="metadata-vocabulary-agent"/></p></item>
+<item><p><specref ref="metadata-vocabulary-name"/></p></item>
+<item><p><specref ref="metadata-vocabulary-actor"/></p></item>
+</ulist>
+<div3 id="metadata-vocabulary-metadata">
+<head>metadata</head>
+<p>The <el>metadata</el> element functions as a generic container for metadata
+information.</p>
+<p>Metadata information may be expressed with a <el>metadata</el> element by specifying
+(1) one or more metadata attributes on the <el>metadata</el> element,
+(2) one or more metadata child elements in the <el>metadata</el> element, or
+(3) a combination of metadata attributes and metadata child elements.  Both types
+of metadata information are referred to in this document as <emph>metadata
+items</emph>.</p>
+<table id="elt-syntax-metadata" role="syntax">
+<caption>XML Representation &ndash; Element Information Item: metadata</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;metadata
+  <loc href="#content-attribute-id">xml:id</loc> = ID
+  <loc href="#content-attribute-lang">xml:lang</loc> = string
+  <loc href="#content-attribute-space">xml:space</loc> = (<emph>default</emph>|<emph>preserve</emph>)
+  {<emph>any attribute in TT Metadata namespace</emph>}
+  {<emph>any attribute not in default or any TT namespace</emph>}&gt;
+  <emph>Content:</emph> ({<emph>any element in TT Metadata namespace</emph>}|{<emph>any element not in any TT namespace</emph>})*
+&lt;/metadata&gt;
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<note role="explanation">
+<p>The meaning of a specific metadata item must be evaluated in the
+context where it appears. The core vocabulary catalog permits an
+arbitrary number of <el>metadata</el> element children on any
+content element type except for the <el>tt</el> element. See specific element
+vocabulary definitions for any constraints that apply to such
+usage.</p>
+</note>
+<p>The use of document metadata is illustrated by the following example.</p>
+<table id="metadata-vocabulary-metadata-example-1" role="example">
+<caption>Example Fragment &ndash; Document Metadata</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+...
+&lt;head&gt;
+  &lt;metadata xmlns:ttm="http://www.w3.org/ns/ttml#metadata"&gt;
+    &lt;ttm:title&gt;Document Metadata Example&lt;/ttm:title&gt;
+    &lt;ttm:desc&gt;This document employs document metadata.&lt;/ttm:desc&gt;
+  &lt;/metadata&gt;
+&lt;/head&gt;
+...
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p></p>
+<p>The use of element metadata is illustrated by the following example.</p>
+<table id="metadata-vocabulary-metadata-example-2" role="example">
+<caption>Example Fragment &ndash; Element Metadata</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+...
+&lt;div&gt;
+  &lt;metadata xmlns:ttm="http://www.w3.org/ns/ttml#metadata"&gt;
+    &lt;ttm:title&gt;Chapter 6 &ndash; Sherlock Holmes Gives a Demonstration&lt;/ttm:title&gt;
+    &lt;ttm:desc&gt;Holmes shows Watson how the murderer entered the window.&lt;/ttm:desc&gt;
+  &lt;/metadata&gt;
+&lt;/div&gt;
+...
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p></p>
+
+<p>The use of metadata attribute items is illustrated by the following example.</p>
+<table id="metadata-vocabulary-metadata-example-3" role="example">
+<caption>Example Fragment &ndash; Foreign Metadata Attribute Items</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+...
+&lt;div xmlns:ext="http://example.org/ttml#metadata"&gt;
+  &lt;metadata ext:ednote="remove this division prior to publishing"/&gt;
+&lt;/div&gt;
+...
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<note role="explanation">
+<p>In the above example, a global attribute from a foreign (external)
+namespace is used to express a metadata attribute that applies
+semantically to the containing <el>div</el> element. Note that the
+attribute may also be expressed directly on the <el>div</el> element;
+however, in this case the author wishes to segregate certain metadata
+attributes by expressing them indirectly on <el>metadata</el>
+elements.</p>
+</note>
+<p></p>
+<p>The use of foreign element metadata is illustrated by the following example.</p>
+<table id="metadata-vocabulary-metadata-example-4" role="example">
+<caption>Example Fragment &ndash; Foreign Element Metadata</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+...
+&lt;metadata
+  xmlns:dc="http://purl.org/dc/elements/1.1/"
+  xmlns:dcterms="http://purl.org/dc/terms/"
+  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"&gt;
+  &lt;dc:title&gt;Foreign Element Metadata Example&lt;/dc:title&gt;
+  &lt;dc:description&gt;Express metadata using elements in foreign namespace.&lt;/dc:description&gt;
+  &lt;dc:format xsi:type="dcterms:IMT"&gt;application/ttml+xml&lt;/dc:format&gt;
+&lt;/metadata&gt;
+...
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<note role="explanation">
+<p>In the above example, a number of elements defined by the Dublin
+Core metadata vocabulary are used to express document level metadata.</p>
+</note>
+<p></p>
+</div3>
+<div3 id="metadata-vocabulary-title">
+<head>ttm:title</head>
+<p>The <el>ttm:title</el> element is used to express a human-readable title of
+a specific element instance.</p>
+<table id="elt-syntax-metadata-title" role="syntax">
+<caption>XML Representation &ndash; Element Information Item: ttm:title</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;ttm:title
+  <loc href="#content-attribute-id">xml:id</loc> = ID
+  <loc href="#content-attribute-lang">xml:lang</loc> = string
+  <loc href="#content-attribute-space">xml:space</loc> = (<emph>default</emph>|<emph>preserve</emph>)
+  {<emph>any attribute not in default or any TT namespace</emph>}&gt;
+  <emph>Content:</emph> #PCDATA
+&lt;/ttm:title&gt;
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<note role="elaboration">
+<p>No specific use of the <el>ttm:title</el> element is defined by this specification.</p>
+</note>
+<p>Examples of the <att>ttm:title</att> element are shown above in
+<specref ref="metadata-vocabulary-metadata-example-1"/> and
+<specref ref="metadata-vocabulary-metadata-example-2"/>.</p>
+</div3>
+<div3 id="metadata-vocabulary-desc">
+<head>ttm:desc</head>
+<p>The <el>ttm:desc</el> element is used to express a human-readable description of
+a specific element instance.</p>
+<table id="elt-syntax-metadata-desc" role="syntax">
+<caption>XML Representation &ndash; Element Information Item: ttm:desc</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;ttm:desc
+  <loc href="#content-attribute-id">xml:id</loc> = ID
+  <loc href="#content-attribute-lang">xml:lang</loc> = string
+  <loc href="#content-attribute-space">xml:space</loc> = (<emph>default</emph>|<emph>preserve</emph>)
+  {<emph>any attribute not in default or any TT namespace</emph>}&gt;
+  <emph>Content:</emph> #PCDATA
+&lt;/ttm:desc&gt;
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<note role="elaboration">
+<p>No specific use of the <el>ttm:desc</el> element is defined by this specification.</p>
+</note>
+<p>Examples of the <att>ttm:desc</att> element are shown above in
+<specref ref="metadata-vocabulary-metadata-example-1"/> and
+<specref ref="metadata-vocabulary-metadata-example-2"/>.</p>
+</div3>
+<div3 id="metadata-vocabulary-copyright">
+<head>ttm:copyright</head>
+<p>The <el>ttm:copyright</el> element is used to express a human-readable copyright that
+applies to some scoping level.</p>
+<p>A copyright statement that applies to a document as a whole should appear as a
+child of the <el>head</el> element.</p>
+<table id="elt-syntax-metadata-copyright" role="syntax">
+<caption>XML Representation &ndash; Element Information Item: ttm:copyright</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;ttm:copyright
+  <loc href="#content-attribute-id">xml:id</loc> = ID
+  <loc href="#content-attribute-lang">xml:lang</loc> = string
+  <loc href="#content-attribute-space">xml:space</loc> = (<emph>default</emph>|<emph>preserve</emph>)
+  {<emph>any attribute not in default or any TT namespace</emph>}&gt;
+  <emph>Content:</emph> #PCDATA
+&lt;/ttm:copyright&gt;
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<note role="elaboration">
+<p>No specific use of the <el>ttm:copyright</el> element is defined by this specification.</p>
+</note>
+</div3>
+<div3 id="metadata-vocabulary-agent">
+<head>ttm:agent</head>
+<p>The <el>ttm:agent</el> element is used to define an agent for the purpose of associating
+content information with an agent who is involved in the production or expression of that content.</p>
+<p>The <el>ttm:agent</el> element accepts as its children zero or more <el>ttm:name</el> elements followed by
+zero or one <el>ttm:actor</el> element.</p>
+<p>At least one <el>ttm:name</el> element child should be specified that expresses a name for the
+agent, whether it be the name of a person, character, group, or organization.</p>
+<table id="elt-syntax-metadata-agent" role="syntax">
+<caption>XML Representation &ndash; Element Information Item: ttm:agent</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;ttm:agent
+  <phrase role="reqattr">type</phrase> = (<emph>person</emph>|<emph>character</emph>|<emph>group</emph>|<emph>organization</emph>|<emph>other</emph>)
+  <loc href="#content-attribute-id">xml:id</loc> = ID
+  <loc href="#content-attribute-lang">xml:lang</loc> = string
+  <loc href="#content-attribute-space">xml:space</loc> = (<emph>default</emph>|<emph>preserve</emph>)
+  {<emph>any attribute not in default or any TT namespace</emph>}&gt;
+  <emph>Content:</emph> <loc href="#metadata-vocabulary-name">ttm:name</loc>*, <loc href="#metadata-vocabulary-actor">ttm:actor</loc>?
+&lt;/ttm:agent&gt;
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p>A <att>type</att> attribute must be specified on each <el>ttm:agent</el> element, and,
+if specified, must have one of the following values:</p>
+<ulist>
+<item><p><el>person</el></p></item>
+<item><p><el>character</el></p></item>
+<item><p><el>group</el></p></item>
+<item><p><el>organization</el></p></item>
+<item><p><el>other</el></p></item>
+</ulist>
+<p>If the value of the <att>type</att> attribute is <code>character</code>, then the
+<el>ttm:agent</el> element instance should specify a <el>ttm:actor</el> child that
+specifies the agent that plays the role of the actor.</p>
+<p>A <att>ttm:agent</att> metadata item is considered to be significant only
+when specified as a child of the <el>head</el> element or as a child of a
+<el>metadata</el> element child of the <el>head</el> element.</p>
+<note role="elaboration">
+<p>A <el>ttm:agent</el> element instance is typically referenced using a <att>ttm:agent</att>
+attribute on a content element.</p>
+</note>
+<note role="elaboration">
+<p>If a character agent is played by multiple actors, then multiple character
+agents may be specified (and referenced) wherein different definitions of the
+character specify different actors.</p>
+</note>
+<p>The use of agent metadata is illustrated by the following example.</p>
+<table id="metadata-vocabulary-agent-example-1" role="example">
+<caption>Example Fragment &ndash; Agent Metadata</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+
+&lt;tt xml:lang="en" xmlns="http://www.w3.org/ns/ttml" xmlns:ttm="http://www.w3.org/ns/ttml#metadata"&gt;
+  &lt;head&gt;
+    <phrase role="strong">&lt;ttm:agent xml:id="connery" type="person"&gt;</phrase>
+      &lt;ttm:name type="family"&gt;Connery&lt;/ttm:name&gt;
+      &lt;ttm:name type="given"&gt;Thomas Sean&lt;/ttm:name&gt;
+      &lt;ttm:name type="alias"&gt;Sean&lt;/ttm:name&gt;
+      &lt;ttm:name type="full"&gt;Sir Thomas Sean Connery&lt;/ttm:name&gt;
+    <phrase role="strong">&lt;/ttm:agent&gt;</phrase>
+    <phrase role="strong">&lt;ttm:agent xml:id="bond" type="character"&gt;</phrase>
+      &lt;ttm:name type="family"&gt;Bond&lt;/ttm:name&gt;
+      &lt;ttm:name type="given"&gt;James&lt;/ttm:name&gt;
+      &lt;ttm:name type="alias"&gt;007&lt;/ttm:name&gt;
+      &lt;ttm:actor agent="connery"/&gt;
+    <phrase role="strong">&lt;/ttm:agent&gt;</phrase>
+  &lt;/head&gt;
+  &lt;body&gt;
+    &lt;div&gt;
+      ...  
+      &lt;p <phrase role="strong">ttm:agent="bond"</phrase>&gt;I travel, a sort of licensed troubleshooter.&lt;/p&gt;
+      ...  
+    &lt;/div&gt;
+  &lt;/body&gt;
+&lt;/tt&gt;
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<note role="explanation">
+<p>In the above example, two agents, a real (person) agent, Sean
+Connery, and a fictitious (character) agent, James Bond, are defined,
+where the latter is linked to the former by means of the a
+<el>ttm:actor</el> element. A reference is then made from content (the
+<el>p</el> element) to the character agent associated with
+(responsible for producing) that content. Note that in this example
+the <el>ttm:agent</el> metadata items are specified as immediate
+children of the document's <el>head</el> element rather than being
+placed in a container <el>metadata</el> element.</p>
+</note>
+</div3>
+<div3 id="metadata-vocabulary-name">
+<head>ttm:name</head>
+<p>The <el>ttm:name</el> element is used to specify a name of a person, character,
+group, or organization.</p>
+<table id="elt-syntax-metadata-name" role="syntax">
+<caption>XML Representation &ndash; Element Information Item: ttm:name</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;ttm:name
+  <phrase role="reqattr">type</phrase> = (<emph>full</emph>|<emph>family</emph>|<emph>given</emph>|<emph>alias</emph>|<emph>other</emph>)
+  <loc href="#content-attribute-id">xml:id</loc> = ID
+  <loc href="#content-attribute-lang">xml:lang</loc> = string
+  <loc href="#content-attribute-space">xml:space</loc> = (<emph>default</emph>|<emph>preserve</emph>)
+  {<emph>any attribute not in default or any TT namespace</emph>}&gt;
+  <emph>Content:</emph> #PCDATA
+&lt;/ttm:name&gt;
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p>A <att>type</att> attribute must be specified on each <el>ttm:name</el> element, and,
+if specified, must have one of the following values:</p>
+<ulist>
+<item><p><el>full</el></p></item>
+<item><p><el>family</el></p></item>
+<item><p><el>given</el></p></item>
+<item><p><el>alias</el></p></item>
+<item><p><el>other</el></p></item>
+</ulist>
+<p>The relationship between the type of a name and the syntactic expression of the name
+is not defined by this specification.</p>
+<p>Two examples of the <el>ttm:name</el> element are shown above in
+<specref ref="metadata-vocabulary-agent-example-1"/>.</p>
+</div3>
+<div3 id="metadata-vocabulary-actor">
+<head>ttm:actor</head>
+<p>The <el>ttm:actor</el> element is used to link the definition of a (role-based) character
+agent with another agent that portrays the character.</p>
+<table id="elt-syntax-metadata-actor" role="syntax">
+<caption>XML Representation &ndash; Element Information Item: ttm:actor</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;ttm:actor
+  <phrase role="reqattr">agent</phrase> = IDREF
+  <loc href="#content-attribute-id">xml:id</loc> = ID
+  <loc href="#content-attribute-lang">xml:lang</loc> = string
+  <loc href="#content-attribute-space">xml:space</loc> = (<emph>default</emph>|<emph>preserve</emph>)
+  {<emph>any attribute not in default or any TT namespace</emph>}&gt;
+  <emph>Content:</emph> EMPTY
+&lt;/ttm:actor&gt;
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p>The <att>agent</att> attribute of a <el>ttm:actor</el> element must
+reference a <emph>significant</emph> <el>ttm:agent</el> element that denotes the person,
+group, or organization acting the part of a character.</p>
+<p>An example of the <el>ttm:actor</el> element is shown above in
+<specref ref="metadata-vocabulary-agent-example-1"/>.</p>
+</div3>
+</div2>
+<div2 id="metadata-attribute-vocabulary">
+<head>Metadata Attribute Vocabulary</head>
+<p>This section specifies the following attributes in the TT Metadata Namespace
+for use with the <el>metadata</el> element and with certain content elements:</p>
+<ulist>
+<item><p><specref ref="metadata-attribute-agent"/></p></item>
+<item><p><specref ref="metadata-attribute-role"/></p></item>
+</ulist>
+<note role="explanation">
+<p>Only certain metadata item attributes may be used with content elements. See
+the definitions of content elements to determine permissible usage.</p>
+</note>
+<div3 id="metadata-attribute-agent">
+<head>ttm:agent</head>
+<p>The <att>ttm:agent</att> attribute takes an <code>IDREFS</code>
+value, and is used with certain content elements to designate the
+agents that perform or are
+involved in the performance of the content.</p>
+<p>If specified, a <att>ttm:agent</att> attribute must reference <emph>significant</emph>
+<el>ttm:agent</el> element instances that appear
+as a descendent of the same <emph>Document Instance</emph> as
+that of the referring element.</p>
+<p>The same IDREF, <emph>ID</emph>, should not appear more than once in the value of a <att>ttm:agent</att> attribute.</p>
+<note role="explanation">
+<p>This constraint is intended to discourage the use of redundant agent references.</p>
+</note>
+<p>An example of the <att>ttm:agent</att> attribute is shown above in
+<specref ref="metadata-vocabulary-agent-example-1"/>.</p>
+</div3>
+<div3 id="metadata-attribute-role">
+<head>ttm:role</head>
+<p>The <att>ttm:role</att> attribute may be used by a content author
+to express
+the roles, functions, or characteristics
+of some content element that is so labeled.</p>
+<p>If specified, the value of this attribute must adhere to the following
+syntax, where
+the syntactic element <emph>S</emph> must adhere to production
+[3] <code>S</code> as defined by <bibref ref="xml10"/>&nbsp;&sect;
+2.3:</p>
+<table id="metadata-attribute-role-syntax" role="syntax">
+<caption>Syntax Representation &ndash; ttm:role</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+ttm:role
+  role ( <emph>S</emph> role )*
+
+role
+  : "action"
+  | "caption"
+  | "description"
+  | "dialog"
+  | "expletive"
+  | "kinesic"
+  | "lyrics"
+  | "music"
+  | "narration"
+  | "quality"
+  | "sound"
+  | "source"
+  | "suppressed"
+  | "reproduction"
+  | "thought"
+  | "title"
+  | "transcription"
+  | extension-role
+
+extension-role
+  : "x-" token-char+
+
+token-char
+  : { XML NameChar }    // XML 1.1 Production [4a]
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p>The same <code>role</code> token, <emph>R</emph>, should not appear more than once in the value of a <att>ttm:role</att> attribute.</p>
+<note role="explanation">
+<p>This constraint is intended to discourage the use of redundant role tokens.</p>
+</note>
+<note role="extensibility">
+<p>All values of <att>ttm:role</att> that do not start with the prefix
+<code>x-</code> are reserved for future standardization.</p>
+</note>
+<note role="extensibility">
+<p>If using a custom <code>x-</code> prefixed form of <att>ttm:role</att>, it
+is recommended that an organization unique infix be used as well in order to
+prevent collisions. For example, <code>x-example-org-custom-role</code>. Furthermore,
+a registry for role values is available at
+<loc href="http://www.w3.org/wiki/TTML/RoleRegistry">http://www.w3.org/wiki/TTML/RoleRegistry</loc>
+in order to promote interoperability and collision avoidance.</p>
+</note>
+</div3>
+</div2>
+</div1>
+</body>
+<back>
+<div1 id="reduced-infoset">
+<head>Reduced XML Infoset</head>
+<p><emph>This appendix is normative.</emph></p>
+<p>For the purposes of this specification, a <emph>Reduced XML Infoset</emph> is
+an XML Information Set <bibref ref="infoset"/> that consists of only the following information items
+and information item properties:</p>
+<div2 id="reduced-infoset-document">
+<head>Document Information Item</head>
+<ulist>
+<item><p><code>[document element]</code></p></item>
+</ulist>
+</div2>
+<div2 id="reduced-infoset-element">
+<head>Element Information Item</head>
+<ulist>
+<item><p><code>[namespace URI]</code></p></item>
+<item><p><code>[local name]</code></p></item>
+<item><p><code>[children]</code></p></item>
+<item><p><code>[attributes]</code></p></item>
+</ulist>
+<p>Child information items <code>[children]</code> are reduced to 
+only element and character information items.</p>
+</div2>
+<div2 id="reduced-infoset-attribute">
+<head>Attribute Information Item</head>
+<ulist>
+<item><p><code>[namespace URI]</code></p></item>
+<item><p><code>[local name]</code></p></item>
+<item><p><code>[normalized value]</code></p></item>
+</ulist>
+</div2>
+<div2 id="reduced-infoset-character">
+<head>Character Information Item</head>
+<ulist>
+<item><p><code>[character code]</code></p></item>
+</ulist>
+<p>Contiguous character information items are not required to be represented distinctly,
+but may be aggregated (chunked) into a sequence of character codes (i.e., a character string).</p>
+</div2>
+</div1>
+<div1 id="schemas">
+<head>Schemas</head>
+<p><emph>This appendix is normative.</emph></p>
+<p>This appendix specifies the following schemas for use with
+<emph>Document Instances</emph>:</p>
+<ulist>
+<item><p>Relax NG, Compact Syntax (RNC) Schema</p></item>
+<item><p>XML Schema Definition (XSD) Schema</p></item>
+</ulist>
+<p>In any case where a schema specified by this appendix differs from the
+normative definitions of document type, element type, or attribute type
+as defined by the body of this specification, then the body of this
+specification takes precedence.</p>
+<div2 id="ttml-schema-rnc">
+<head>Relax NG Compact (RNC) Schema</head>
+<p>A Relax NG Compact Syntax (RNC) <bibref ref="rng"/> based schema
+for TTML Content is available at <loc href="rnc/schema.zip">ZIP
+Archive</loc>. This schema does not normatively define the validity
+of Timed Text Markup Language content as defined by this specification.
+In particular, the formal validity of TTML Content
+is defined by <specref ref="conformance-content"/>.</p>
+</div2>
+<div2 id="ttml-schema-xsd">
+<head>XML Schema Definition (XSD) Schema</head>
+<p>A W3C XML Schema Definition (XSD) <bibref ref="xsd-1"/> based schema
+for TTML Content is available at <loc href="xsd/schema.zip">ZIP
+Archive</loc>. This schema does not normatively define the validity
+of Timed Text Markup Language content as defined by this specification.
+In particular, the formal validity of TTML Content
+is defined by <specref ref="conformance-content"/>.</p>
+</div2>
+</div1>
+<div1 id="media-types-registration">
+<head>Media Type Registration</head>
+<p><emph>This appendix is normative.</emph></p>
+<p>This appendix registers a new media type,
+"application/ttml+xml" in conformance with
+<loc href="http://www.ietf.org/rfc/rfc4288.txt">BCP 13</loc> and
+<loc
+href="http://www.w3.org/2002/06/registering-mediatype.html">W3CRegMedia</loc>.
+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>
+<glist>
+<gitem>
+<label>Type name:</label>
+<def>
+<p>application</p>
+</def>
+</gitem>
+<gitem>
+<label>Subtype name:</label>
+<def>
+<p>ttml+xml</p>
+</def>
+</gitem>
+<gitem>
+<label>Required parameters:</label>
+<def>
+<p>None.</p>
+</def>
+</gitem>
+<gitem>
+<label>Optional parameters:</label>
+<def>
+<glist>
+<gitem>
+<label>charset</label>
+<def>
+<p>If specified, the <code>charset</code> parameter must match the XML encoding declaration, or if absent, the actual encoding.</p>
+</def>
+</gitem>
+<gitem>
+<label>profile</label>
+<def>
+<p>The document profile of a TTMLDocument Instance 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
+<att>ttp:profile</att> parameter defined by
+Section
+<specref ref="parameter-attribute-profile"/>
+of the published specification.</p>
+</def>
+</gitem>
+</glist>
+</def>
+</gitem>
+<gitem>
+<label>Encoding considerations:</label>
+<def>
+<p>Same for application/xml, except constrained to either UTF-8 or UTF-16. See <bibref ref="xml-media"/>, Section
+3.2.</p>
+</def>
+</gitem>
+<gitem>
+<label>Security considerations:</label>
+<def>
+<p>As with other XML types and as noted in
+<bibref ref="xml-media"/>
+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,
+TTML does not provide for any sort of active or executable content, and
+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>
+<p>Although not prohibited, there are no expectations that XML signatures
+or encryption would normally be employed.</p>
+</def>
+</gitem>
+<gitem>
+<label>Interoperability considerations:</label>
+<def>
+<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 may
+expect (and enforce) 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>
+</def>
+</gitem>
+<gitem>
+<label>Published specification:</label>
+<def>
+<p>This media type registration is extracted from Appendix C Media Type
+Registration of the Timed Text Markup Language (TTML) 1.0 specification:
+<loc
+href="http://www.w3.org/TR/ttaf1-dfxp/">Timed Text Markup Language (TTML) 1.0</loc>.</p>
+</def>
+</gitem>
+<gitem>
+<label>Applications that use this media type:</label>
+<def>
+<p>TTML is used in the television industry for the purpose of authoring, transcoding and exchanging timed text information and for delivering captions, subtitles, and
+other metadata for television material repurposed for the Web or, more generally, 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>
+</def>
+</gitem>
+<gitem>
+<label>Additional information:</label>
+<def>
+<glist>
+<gitem>
+    <label>Magic number(s):</label>
+    <def></def>
+</gitem>
+<gitem>
+    <label>File extension(s):</label>
+    <def><p>.ttml</p></def>
+</gitem>
+<gitem>
+    <label>Macintosh file type code(s):</label>
+    <def><p>"TTML"</p></def>
+</gitem>
+<gitem>
+<label>Fragment identifiers:</label>
+<def><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 <loc
+href="http://www.w3.org/TR/ttaf1-dfxp/">Timed Text Markup Language (TTML) 1.0</loc> specification.</p></def>
+</gitem>
+</glist>
+</def>
+</gitem>
+<gitem>
+<label>Person &amp; email address to contact for further information:</label>
+<def>
+<p>Timed Text Working Group (public-tt@w3.org)</p>
+</def>
+</gitem>
+<gitem>
+<label>Intended usage:</label>
+<def>
+<p>COMMON</p>
+</def>
+</gitem>
+<gitem>
+<label>Restrictions on usage:</label>
+<def>
+<p>None</p>
+</def>
+</gitem>
+<gitem>
+<label>Author:</label>
+<def>
+<p>The published specification is a work product of the World Wide Web
+Consortium's Timed Text (TT) Working Group.</p>
+</def>
+</gitem>
+<gitem>
+<label>Change controller:</label>
+<def>
+<p>The W3C has change control over this specification.</p>
+</def>
+</gitem>
+</glist>
+</div1>
+<div1 id="features">
+<head>Features</head>
+<p><emph>This appendix is normative.</emph></p>
+<p>This appendix specifies (1) a set of feature designations, each of which
+labels one or more syntactic and/or semantic features defined by this
+specification, and (2) for each designated feature, whether the feature is mandatory
+or optional for a transformation or presentation processor.</p>
+<note>
+<p>A TTML processor is said to <emph>implement the transformation semantics</emph> or
+<emph>implement the presentation semantics</emph> of feature designation <emph>F</emph>
+if it satisfies the requirements of this appendix with respect to the definition of
+feature designation <emph>F</emph> as pertains to transformation or
+presentation processing, respectively.</p>
+</note>
+<div2 id="feature-designations">
+<head>Feature Designations</head>
+<p>A feature designation is expressed as a string that adheres to the following
+form:</p>
+<eg xml:space="preserve">
+feature-designation
+  : feature-namespace designation
+
+feature-namespace
+  : <emph>TT Feature Namespace</emph>                    // http://www.w3.org/ns/ttml/feature/
+
+designation
+  : "#" token-char+
+
+token-char
+  : { XML NameChar }                        // XML 1.1 Production [4a]
+</eg>
+<p>All values of <code>feature-designation</code> not defined by this specification are reserved
+for future standardization.</p>
+<p>The following sub-sections define all feature designations, expressed
+as relative URIs (fragment identifiers) with respect to the 
+TT Feature Namespace base URI.</p>
+<div3 id="feature-animation">
+<head>#animation</head>
+<p>A TTML transformation processor supports the <code>#animation</code>
+feature if it recognizes and is capable of transforming the following
+vocabulary defined by <specref ref="animation"/>:</p>
+<ulist>
+<item><p><loc href="#animation-vocabulary-set"><el>set</el></loc></p></item>
+</ulist>
+<p>A TTML presentation processor supports the <code>#animation</code>
+feature if it implements presentation semantic support for the
+same vocabulary enumerated above.</p>
+</div3>
+<div3 id="feature-backgroundColor">
+<head>#backgroundColor</head>
+<p>A TTML transformation processor supports the
+<code>#backgroundColor</code> feature if it recognizes and is capable of
+transforming the <loc
+href="#style-attribute-backgroundColor"><att>tts:backgroundColor</att></loc>
+attribute.</p>
+<p>A TTML presentation processor supports the
+<code>#backgroundColor</code> feature if it (1) implements presentation semantic support
+for the <loc
+href="#style-attribute-backgroundColor"><att>tts:backgroundColor</att></loc>
+attribute
+and (2) is capable of displaying or generating an output display
+signal that distinguishes between at least sixteen (16) values of color,
+including all primary and secondary colors of the SRGB color space.</p>
+</div3>
+<div3 id="feature-backgroundColor-block">
+<head>#backgroundColor-block</head>
+<p>A TTML transformation processor supports the
+<code>#backgroundColor-block</code> feature if it recognizes and is
+capable of transforming all defined values of the <loc
+href="#style-attribute-backgroundColor"><att>tts:backgroundColor</att></loc>
+attribute when applied to a content element that would generate a
+block area during presentation processing.</p>
+<p>A TTML presentation processor supports the
+<code>#backgroundColor-block</code> feature if it (1) implements presentation semantic
+support for the <loc
+href="#style-attribute-backgroundColor"><att>tts:backgroundColor</att></loc>
+attribute when applied to a content element that generates a
+block area
+and (2) is capable of displaying or generating an output display
+signal that distinguishes between at least sixteen (16) values of color,
+including all primary and secondary colors of the SRGB color space.</p>
+</div3>
+<div3 id="feature-backgroundColor-inline">
+<head>#backgroundColor-inline</head>
+<p>A TTML transformation processor supports the
+<code>#backgroundColor-inline</code> feature if it recognizes and is
+capable of transforming all defined values of the <loc
+href="#style-attribute-backgroundColor"><att>tts:backgroundColor</att></loc>
+attribute when applied to a content element that would generate an
+inline area during presentation processing.</p>
+<p>A TTML presentation processor supports the
+<code>#backgroundColor-inline</code> feature if it (1) implements presentation semantic
+support for the <loc
+href="#style-attribute-backgroundColor"><att>tts:backgroundColor</att></loc>
+attribute when applied to a content element that generates an
+inline area
+and (2) is capable of displaying or generating an output display
+signal that distinguishes between at least sixteen (16) values of color,
+including all primary and secondary colors of the SRGB color space.</p>
+</div3>
+<div3 id="feature-backgroundColor-region">
+<head>#backgroundColor-region</head>
+<p>A TTML transformation processor supports the
+<code>#backgroundColor-region</code> feature if it recognizes and is
+capable of transforming all defined values of the <loc
+href="#style-attribute-backgroundColor"><att>tts:backgroundColor</att></loc>
+attribute when applied to a <loc
+href="#layout-vocabulary-region"><el>region</el></loc> element.</p>
+<p>A TTML presentation processor supports the
+<code>#backgroundColor-region</code> feature if it (1) implements presentation semantic
+support for the <loc
+href="#style-attribute-backgroundColor"><att>tts:backgroundColor</att></loc>
+attribute when applied to a <loc
+href="#layout-vocabulary-region"><el>region</el></loc> element
+and (2) is capable of displaying or generating an output display
+signal that distinguishes between at least sixteen (16) values of color,
+including all primary and secondary colors of the SRGB color space
+.</p>
+</div3>
+<div3 id="feature-bidi">
+<head>#bidi</head>
+<p>A TTML processor supports the <code>#bidi</code> feature if it
+supports the following features:</p>
+<ulist>
+<item><p><loc
+href="#feature-direction"><code>#direction</code></loc></p></item>
+<item><p><loc
+href="#feature-unicodeBidi"><code>#unicodeBidi</code></loc></p></item>
+<item><p><loc
+href="#feature-writingMode-horizontal"><code>#writingMode-horizontal</code></loc></p></item>
+</ulist>
+</div3>
+<div3 id="feature-cellResolution">
+<head>#cellResolution</head>
+<p>A TTML transformation processor supports the
+<code>#cellResolution</code> feature if it recognizes and is capable of
+transforming the <loc
+href="#parameter-attribute-cellResolution"><att>ttp:cellResolution</att></loc>
+attribute.</p>
+<p>A TTML presentation processor supports the
+<code>#cellResolution</code> feature if it implements presentation semantic support
+for the <loc
+href="#parameter-attribute-cellResolution"><att>ttp:cellResolution</att></loc>
+attribute.</p>
+</div3>
+<div3 id="feature-clockMode">
+<head>#clockMode</head>
+<p>A TTML transformation processor supports the
+<code>#clockMode</code> feature if it recognizes and is capable of
+transforming the <loc
+href="#parameter-attribute-clockMode"><att>ttp:clockMode</att></loc>
+attribute.</p>
+<p>A TTML presentation processor supports the
+<code>#clockMode</code> feature if it implements presentation semantic support
+for the <loc
+href="#parameter-attribute-clockMode"><att>ttp:clockMode</att></loc>
+attribute.</p>
+</div3>
+<div3 id="feature-clockMode-gps">
+<head>#clockMode-gps</head>
+<p>A TTML transformation processor supports the
+<code>#clockMode-gps</code> feature if it recognizes and is capable of
+transforming the <code>gps</code> value of the <loc
+href="#parameter-attribute-clockMode"><att>ttp:clockMode</att></loc>
+attribute.</p>
+<p>A TTML presentation processor supports the
+<code>#clockMode-gps</code> feature if it implements presentation semantic support
+for the <code>gps</code> value of the <loc
+href="#parameter-attribute-clockMode"><att>ttp:clockMode</att></loc>
+attribute.</p>
+</div3>
+<div3 id="feature-clockMode-local">
+<head>#clockMode-local</head>
+<p>A TTML transformation processor supports the
+<code>#clockMode-local</code> feature if it recognizes and is capable of
+transforming the <code>local</code> value of the <loc
+href="#parameter-attribute-clockMode"><att>ttp:clockMode</att></loc>
+attribute.</p>
+<p>A TTML presentation processor supports the
+<code>#clockMode-local</code> feature if it implements presentation semantic support
+for the <code>local</code> value of the <loc
+href="#parameter-attribute-clockMode"><att>ttp:clockMode</att></loc>
+attribute.</p>
+</div3>
+<div3 id="feature-clockMode-utc">
+<head>#clockMode-utc</head>
+<p>A TTML transformation processor supports the
+<code>#clockMode-utc</code> feature if it recognizes and is capable of
+transforming the <code>utc</code> value of the <loc
+href="#parameter-attribute-clockMode"><att>ttp:clockMode</att></loc>
+attribute.</p>
+<p>A TTML presentation processor supports the
+<code>#clockMode-utc</code> feature if it implements presentation semantic support
+for the <code>utc</code> value of the <loc
+href="#parameter-attribute-clockMode"><att>ttp:clockMode</att></loc>
+attribute.</p>
+</div3>
+<div3 id="feature-color">
+<head>#color</head>
+<p>A TTML transformation processor supports the
+<code>#color</code> feature if it recognizes and is capable of
+transforming the <loc
+href="#style-attribute-color"><att>tts:color</att></loc>
+attribute.</p>
+<p>A TTML presentation processor supports the
+<code>#color</code> feature if it (1) implements presentation semantic support
+for the <loc
+href="#style-attribute-color"><att>tts:color</att></loc>
+attribute
+and (2) is capable of displaying or generating an output display
+signal that distinguishes between at least sixteen (16) values of color,
+including all primary and secondary colors of the SRGB color space.</p>
+</div3>
+<div3 id="feature-content">
+<head>#content</head>
+<p>A TTML transformation processor supports the <code>#content</code>
+feature if it recognizes and is capable of transforming the following
+vocabulary defined by <specref ref="content"/>:</p>
+<ulist>
+<item><p><loc href="#document-structure-vocabulary-body"><el>body</el></loc></p></item>
+<item><p><loc href="#content-vocabulary-div"><el>div</el></loc></p></item>
+<item><p><loc href="#content-vocabulary-p"><el>p</el></loc></p></item>
+<item><p><loc href="#content-vocabulary-span"><el>span</el></loc></p></item>
+<item><p><loc href="#content-vocabulary-br"><el>br</el></loc></p></item>
+</ulist>
+<p>A TTML presentation processor supports the <code>#content</code>
+feature if it implements presentation semantic support for the
+same vocabulary enumerated above.</p>
+</div3>
+<div3 id="feature-core">
+<head>#core</head>
+<p>A TTML transformation processor supports the <code>#core</code>
+feature if it recognizes and is capable of transforming the following
+core attributes vocabulary defined by <specref ref="content"/>:</p>
+<ulist>
+<item><p><loc href="#content-attribute-id">@<att>xml:id</att></loc></p></item>
+<item><p><loc href="#content-attribute-id">@<att>xml:lang</att></loc></p></item>
+<item><p><loc href="#content-attribute-id">@<att>xml:space</att></loc></p></item>
+</ulist>
+<p>A TTML presentation processor supports the <code>#core</code>
+feature if it implements presentation semantic support for the
+same vocabulary enumerated above.</p>
+</div3>
+<div3 id="feature-direction">
+<head>#direction</head>
+<p>A TTML transformation processor supports the
+<code>#direction</code> feature if it recognizes and is capable of
+transforming all defined values of the <loc
+href="#style-attribute-direction"><att>tts:direction</att></loc>
+attribute.</p>
+<p>A TTML presentation processor supports the
+<code>#direction</code> feature if it implements presentation semantic support
+for all defined values of the <loc
+href="#style-attribute-direction"><att>tts:direction</att></loc>
+attribute.</p>
+</div3>
+<div3 id="feature-display">
+<head>#display</head>
+<p>A TTML transformation processor supports the
+<code>#display</code> feature if it recognizes and is capable of
+transforming all defined values of the <loc
+href="#style-attribute-display"><att>tts:display</att></loc>
+attribute.</p>
+<p>A TTML presentation processor supports the
+<code>#display</code> feature if it implements presentation semantic support
+for all defined values of the <loc
+href="#style-attribute-display"><att>tts:display</att></loc>
+attribute.</p>
+</div3>
+<div3 id="feature-display-block">
+<head>#display-block</head>
+<p>A TTML transformation processor supports the
+<code>#display-block</code> feature if it recognizes and is
+capable of transforming all defined values of the <loc
+href="#style-attribute-display"><att>tts:display</att></loc>
+attribute when applied to a content element that would generate a
+block area during presentation processing.</p>
+<p>A TTML presentation processor supports the
+<code>#display-block</code> feature if it implements presentation semantic
+support for all defined values of the <loc
+href="#style-attribute-display"><att>tts:display</att></loc>
+attribute when applied to a content element that generates a
+block area.</p>
+</div3>
+<div3 id="feature-display-inline">
+<head>#display-inline</head>
+<p>A TTML transformation processor supports the
+<code>#display-inline</code> feature if it recognizes and is
+capable of transforming all defined values of the <loc
+href="#style-attribute-display"><att>tts:display</att></loc>
+attribute when applied to a content element that would generate an
+inline area during presentation processing.</p>
+<p>A TTML presentation processor supports the
+<code>#display-inline</code> feature if it implements presentation semantic
+support for all defined values of the <loc
+href="#style-attribute-display"><att>tts:display</att></loc>
+attribute when applied to a content element that generates an
+inline area.</p>
+</div3>
+<div3 id="feature-display-region">
+<head>#display-region</head>
+<p>A TTML transformation processor supports the
+<code>#display-region</code> feature if it recognizes and is
+capable of transforming all defined values of the <loc
+href="#style-attribute-display"><att>tts:display</att></loc>
+attribute when applied to a <loc
+href="#layout-vocabulary-region"><el>region</el></loc> element.</p>
+<p>A TTML presentation processor supports the
+<code>#display-region</code> feature if it implements presentation semantic
+support for all defined values of the <loc
+href="#style-attribute-display"><att>tts:display</att></loc>
+attribute when applied to a <loc
+href="#layout-vocabulary-region"><el>region</el></loc> element.</p>
+</div3>
+<div3 id="feature-displayAlign">
+<head>#displayAlign</head>
+<p>A TTML transformation processor supports the
+<code>#displayAlign</code> feature if it recognizes and is capable of
+transforming all defined values of the <loc
+href="#style-attribute-displayAlign"><att>tts:displayAlign</att></loc>
+attribute.</p>
+<p>A TTML presentation processor supports the
+<code>#displayAlign</code> feature if it implements presentation semantic support
+for all defined values of the <loc
+href="#style-attribute-displayAlign"><att>tts:displayAlign</att></loc>
+attribute.</p>
+</div3>
+<div3 id="feature-dropMode">
+<head>#dropMode</head>
+<p>A TTML transformation processor supports the
+<code>#dropMode</code> feature if it recognizes and is capable of
+transforming the <loc
+href="#parameter-attribute-dropMode"><att>ttp:dropMode</att></loc>
+attribute.</p>
+<p>A TTML presentation processor supports the
+<code>#dropMode</code> feature if it implements presentation semantic support
+for the <loc
+href="#parameter-attribute-dropMode"><att>ttp:dropMode</att></loc>
+attribute.</p>
+</div3>
+<div3 id="feature-dropMode-dropNTSC">
+<head>#dropMode-dropNTSC</head>
+<p>A TTML transformation processor supports the
+<code>#dropMode-dropNTSC</code> feature if it recognizes and is capable of
+transforming the <code>dropNTSC</code> value of the <loc
+href="#parameter-attribute-dropMode"><att>ttp:dropMode</att></loc>
+attribute.</p>
+<p>A TTML presentation processor supports the
+<code>#dropMode-dropNTSC</code> feature if it implements presentation semantic support
+for the <code>dropNTSC</code> value of the <loc
+href="#parameter-attribute-dropMode"><att>ttp:dropMode</att></loc>
+attribute.</p>
+</div3>
+<div3 id="feature-dropMode-dropPAL">
+<head>#dropMode-dropPAL</head>
+<p>A TTML transformation processor supports the
+<code>#dropMode-dropPAL</code> feature if it recognizes and is capable of
+transforming the <code>dropPAL</code> value of the <loc
+href="#parameter-attribute-dropMode"><att>ttp:dropMode</att></loc>
+attribute.</p>
+<p>A TTML presentation processor supports the
+<code>#dropMode-dropPAL</code> feature if it implements presentation semantic support
+for the <code>dropPAL</code> value of the <loc
+href="#parameter-attribute-dropMode"><att>ttp:dropMode</att></loc>
+attribute.</p>
+</div3>
+<div3 id="feature-dropMode-nonDrop">
+<head>#dropMode-nonDrop</head>
+<p>A TTML transformation processor supports the
+<code>#dropMode-nonDrop</code> feature if it recognizes and is capable of
+transforming the <code>nonDrop</code> value of the <loc
+href="#parameter-attribute-dropMode"><att>ttp:dropMode</att></loc>
+attribute.</p>
+<p>A TTML presentation processor supports the
+<code>#dropMode-nonDrop</code> feature if it implements presentation semantic support
+for the <code>nonDrop</code> value of the <loc
+href="#parameter-attribute-dropMode"><att>ttp:dropMode</att></loc>
+attribute.</p>
+</div3>
+<div3 id="feature-extent">
+<head>#extent</head>
+<p>A TTML transformation processor supports the
+<code>#extent</code> feature if it recognizes and is capable of
+transforming the <loc
+href="#style-attribute-extent"><att>tts:extent</att></loc>
+attribute.</p>
+<p>A TTML presentation processor supports the
+<code>#extent</code> feature if it implements presentation semantic support for
+the <loc
+href="#style-attribute-extent"><att>tts:extent</att></loc>
+attribute.</p>
+</div3>
+<div3 id="feature-extent-region">
+<head>#extent-region</head>
+<p>A TTML transformation processor supports the
+<code>#extent-region</code> feature if it recognizes and is capable of
+transforming the <loc
+href="#style-attribute-extent"><att>tts:extent</att></loc>
+attribute when applied to a <loc
+href="#layout-vocabulary-region"><el>region</el></loc> element.</p>
+<p>A TTML presentation processor supports the
+<code>#extent-region</code> feature if it implements presentation semantic support for
+the <loc
+href="#style-attribute-extent"><att>tts:extent</att></loc>
+attribute when applied to a <loc
+href="#layout-vocabulary-region"><el>region</el></loc> element.</p>
+</div3>
+<div3 id="feature-extent-root">
+<head>#extent-root</head>
+<p>A TTML transformation processor supports the
+<code>#extent-root</code> feature if it recognizes and is capable of
+transforming the <loc
+href="#style-attribute-extent"><att>tts:extent</att></loc>
+attribute when applied to the <loc
+href="#document-structure-vocabulary-tt"><el>tt</el></loc> element.</p>
+<p>A TTML presentation processor supports the
+<code>#extent-root</code> feature if it implements presentation semantic support for
+the <loc
+href="#style-attribute-extent"><att>tts:extent</att></loc>
+attribute when applied to a <loc
+href="#document-structure-vocabulary-tt"><el>tt</el></loc> element.</p>
+</div3>
+<div3 id="feature-fontFamily">
+<head>#fontFamily</head>
+<p>A TTML transformation processor supports the
+<code>#fontFamily</code> feature if it recognizes and is capable of
+transforming the <loc
+href="#style-attribute-fontFamily"><att>tts:fontFamily</att></loc>
+attribute.</p>
+<p>A TTML presentation processor supports the
+<code>#fontFamily</code> feature if it implements presentation semantic support
+for the <loc
+href="#style-attribute-fontFamily"><att>tts:fontFamily</att></loc>
+attribute.</p>
+</div3>
+<div3 id="feature-fontFamily-generic">
+<head>#fontFamily-generic</head>
+<p>A TTML transformation processor supports the
+<code>#fontFamily-generic</code> feature if it recognizes and is
+capable of transforming <loc
+href="#style-value-genericFamilyName">&lt;genericFamilyName&gt;</loc>
+values when used with the <loc
+href="#style-attribute-fontFamily"><att>tts:fontFamily</att></loc>
+attribute.</p>
+<p>A TTML presentation processor supports the
+<code>#fontFamily-generic</code> feature if it implements presentation semantic
+support for <loc
+href="#style-value-genericFamilyName">&lt;genericFamilyName&gt;</loc>
+values when used with the <loc
+href="#style-attribute-fontFamily"><att>tts:fontFamily</att></loc>
+attribute.</p>
+</div3>
+<div3 id="feature-fontFamily-non-generic">
+<head>#fontFamily-non-generic</head>
+<p>A TTML transformation processor supports the
+<code>#fontFamily-non-generic</code> feature if it recognizes and is
+capable of transforming <loc
+href="#style-value-familyName">&lt;familyName&gt;</loc>
+values when used with the <loc
+href="#style-attribute-fontFamily"><att>tts:fontFamily</att></loc>
+attribute.</p>
+<p>A TTML presentation processor supports the
+<code>#fontFamily-non-generic</code> feature if it implements presentation semantic
+support for <loc
+href="#style-value-familyName">&lt;familyName&gt;</loc>
+values when used with the <loc
+href="#style-attribute-fontFamily"><att>tts:fontFamily</att></loc>
+attribute.</p>
+</div3>
+<div3 id="feature-fontSize">
+<head>#fontSize</head>
+<p>A TTML transformation processor supports the
+<code>#fontSize</code> feature if it recognizes and is capable of
+transforming the <loc
+href="#style-attribute-fontSize"><att>tts:fontSize</att></loc>
+attribute.</p>
+<p>A TTML presentation processor supports the
+<code>#fontSize</code> feature if it implements presentation semantic support
+for the <loc
+href="#style-attribute-fontSize"><att>tts:fontSize</att></loc>
+attribute.</p>
+</div3>
+<div3 id="feature-fontSize-anamorphic">
+<head>#fontSize-anamorphic</head>
+<p>A TTML transformation processor supports the
+<code>#fontSize-anamorphic</code> feature if it recognizes and is
+capable of transforming values of the <loc
+href="#style-attribute-fontSize"><att>tts:fontSize</att></loc>
+attribute that consist of two <loc
+href="#style-value-length">&lt;length&gt;</loc> specifications.</p>
+<p>A TTML presentation processor supports the
+<code>#fontSize-anamorphic</code> feature if it implements presentation semantic
+support for defined values of the <loc
+href="#style-attribute-fontSize"><att>tts:fontSize</att></loc>
+attribute that consist of two <loc
+href="#style-value-length">&lt;length&gt;</loc> specifications.</p>
+</div3>
+<div3 id="feature-fontSize-isomorphic">
+<head>#fontSize-isomorphic</head>
+<p>A TTML transformation processor supports the
+<code>#fontSize-isomorphic</code> feature if it recognizes and is
+capable of transforming values of the <loc
+href="#style-attribute-fontSize"><att>tts:fontSize</att></loc>
+attribute that consist of a single <loc
+href="#style-value-length">&lt;length&gt;</loc> specification.</p>
+<p>A TTML presentation processor supports the
+<code>#fontSize-isomorphic</code> feature if it implements presentation semantic
+support for defined values of the <loc
+href="#style-attribute-fontSize"><att>tts:fontSize</att></loc>
+attribute that consist of a single <loc
+href="#style-value-length">&lt;length&gt;</loc> specification.</p>
+</div3>
+<div3 id="feature-fontStyle">
+<head>#fontStyle</head>
+<p>A TTML transformation processor supports the
+<code>#fontStyle</code> feature if it recognizes and is capable of
+transforming all defined values of the <loc
+href="#style-attribute-fontStyle"><att>tts:fontStyle</att></loc>
+attribute.</p>
+<p>A TTML presentation processor supports the
+<code>#fontStyle</code> feature if it implements presentation semantic support
+for all defined values of the <loc
+href="#style-attribute-fontStyle"><att>tts:fontStyle</att></loc>
+attribute.</p>
+</div3>
+<div3 id="feature-fontStyle-italic">
+<head>#fontStyle-italic</head>
+<p>A TTML transformation processor supports the
+<code>#fontStyle-italic</code> feature if it recognizes and is
+capable of transforming the <code>italic</code> value of the <loc
+href="#style-attribute-fontStyle"><att>tts:fontStyle</att></loc>
+attribute.</p>
+<p>A TTML presentation processor supports the
+<code>#fontStyle-italic</code> feature if it implements presentation semantic
+support for the <code>italic</code> of the <loc
+href="#style-attribute-fontStyle"><att>tts:fontStyle</att></loc>
+attribute.</p>
+</div3>
+<div3 id="feature-fontStyle-oblique">
+<head>#fontStyle-oblique</head>
+<p>A TTML transformation processor supports the
+<code>#fontStyle-oblique</code> feature if it recognizes and is
+capable of transforming the <code>oblique</code> value of the <loc
+href="#style-attribute-fontStyle"><att>tts:fontStyle</att></loc>
+attribute.</p>
+<p>A TTML presentation processor supports the
+<code>#fontStyle-oblique</code> feature if it implements presentation semantic
+support for the <code>oblique</code> of the <loc
+href="#style-attribute-fontStyle"><att>tts:fontStyle</att></loc>
+attribute.</p>
+</div3>
+<div3 id="feature-fontWeight">
+<head>#fontWeight</head>
+<p>A TTML transformation processor supports the
+<code>#fontWeight</code> feature if it recognizes and is capable of
+transforming all defined values of the <loc
+href="#style-attribute-fontWeight"><att>tts:fontWeight</att></loc>
+attribute.</p>
+<p>A TTML presentation processor supports the
+<code>#fontWeight</code> feature if it implements presentation semantic support
+for all defined values of the <loc
+href="#style-attribute-fontWeight"><att>tts:fontWeight</att></loc>
+attribute.</p>
+</div3>
+<div3 id="feature-fontWeight-bold">
+<head>#fontWeight-bold</head>
+<p>A TTML transformation processor supports the
+<code>#fontWeight-bold</code> feature if it recognizes and is
+capable of transforming <code>bold</code> value of the <loc
+href="#style-attribute-fontWeight"><att>tts:fontWeight</att></loc>
+attribute.</p>
+<p>A TTML presentation processor supports the
+<code>#fontWeight-bold</code> feature if it implements presentation semantic
+support for the <code>bold</code> of the <loc
+href="#style-attribute-fontWeight"><att>tts:fontWeight</att></loc>
+attribute.</p>
+</div3>
+<div3 id="feature-frameRate">
+<head>#frameRate</head>
+<p>A TTML transformation processor supports the
+<code>#frameRate</code> feature if it recognizes and is capable of
+transforming the <loc
+href="#parameter-attribute-frameRate"><att>ttp:frameRate</att></loc>
+attribute.</p>
+<p>A TTML presentation processor supports the
+<code>#frameRate</code> feature if it implements presentation semantic support
+for the <loc
+href="#parameter-attribute-frameRate"><att>ttp:frameRate</att></loc>
+attribute.</p>
+</div3>
+<div3 id="feature-frameRateMultiplier">
+<head>#frameRateMultiplier</head>
+<p>A TTML transformation processor supports the
+<code>#frameRateMultiplier</code> feature if it recognizes and is capable of
+transforming the <loc
+href="#parameter-attribute-frameRateMultiplier"><att>ttp:frameRateMultiplier</att></loc>
+attribute.</p>
+<p>A TTML presentation processor supports the
+<code>#frameRateMultiplier</code> feature if it implements presentation semantic support
+for the <loc
+href="#parameter-attribute-frameRateMultiplier"><att>ttp:frameRateMultiplier</att></loc>
+attribute.</p>
+</div3>
+<div3 id="feature-layout">
+<head>#layout</head>
+<p>A TTML transformation processor supports the <code>#layout</code>
+feature if it (1) recognizes and is capable of transforming the following
+vocabulary defined by <specref ref="layout"/>:</p>
+<ulist>
+<item><p><loc href="#layout-vocabulary-layout"><el>layout</el></loc></p></item>
+<item><p><loc href="#layout-vocabulary-region"><el>region</el></loc></p></item>
+<item><p><loc href="#layout-attribute-region">@<att>region</att></loc></p></item>
+</ulist>
+<p>and (2) supports the following attributes when applied to the
+<loc href="#layout-vocabulary-region"><el>region</el></loc> element:</p>
+<ulist>
+<item><p><loc
+href="#style-attribute-extent"><att>tts:extent</att></loc></p></item>
+<item><p><loc
+href="#style-attribute-origin"><att>tts:origin</att></loc></p></item>
+</ulist>
+<p>A TTML presentation processor supports the <code>#layout</code>
+feature if it implements presentation semantic support for the
+same vocabulary and features enumerated above.</p>
+</div3>
+<div3 id="feature-length">
+<head>#length</head>
+<p>A TTML transformation processor supports the <code>#length</code>
+feature if it recognizes and is capable of transforming all defined
+values of the <loc href="#style-value-length">&lt;length&gt;</loc>
+style value expression.</p>
+<p>A TTML presentation processor supports the <code>#length</code>
+feature if it implements presentation semantic support for all defined values of
+the <loc href="#style-value-length">&lt;length&gt;</loc> style value
+expression.</p>
+<note role="clarification">
+<p>Support for <code>#length</code> is intended to imply support for the following features:
+<code>#length-integer</code>,
+<code>#length-real</code>,
+<code>#length-positive</code>,
+<code>#length-negative</code>,
+<code>#length-cell</code>,
+<code>#length-em</code>,
+<code>#length-percentage</code>, and
+<code>#length-pixel</code>.</p>
+</note>
+</div3>
+<div3 id="feature-length-cell">
+<head>#length-cell</head>
+<p>A TTML transformation processor supports the
+<code>#length-cell</code> feature if it recognizes and is capable of
+transforming scalar values of the <loc
+href="#style-value-length">&lt;length&gt;</loc> style value expression
+that use <code>c</code> (cell) units.</p>
+<p>A TTML presentation processor supports the
+<code>#length-cell</code> feature if it implements presentation semantic support
+for scalar values of the <loc
+href="#style-value-length">&lt;length&gt;</loc> style value expression
+that use <code>c</code> (cell) units.</p>
+<note role="clarification">
+<p>Support for <code>#length-cell</code> does not, by itself, imply support for
+<code>#length-integer</code>,
+<code>#length-real</code>,
+<code>#length-positive</code>, or
+<code>#length-negative</code> features.</p>
+</note>
+</div3>
+<div3 id="feature-length-em">
+<head>#length-em</head>
+<p>A TTML transformation processor supports the
+<code>#length-em</code> feature if it recognizes and is capable of
+transforming scalar values of the <loc
+href="#style-value-length">&lt;length&gt;</loc> style value expression
+that use <code>em</code> (EM) units.</p>
+<p>A TTML presentation processor supports the
+<code>#length-em</code> feature if it implements presentation semantic support
+for scalar values of the <loc
+href="#style-value-length">&lt;length&gt;</loc> style value expression
+that use <code>em</code> (EM) units.</p>
+<note role="clarification">
+<p>Support for <code>#length-em</code> does not, by itself, imply support for
+<code>#length-integer</code>,
+<code>#length-real</code>,
+<code>#length-positive</code>, or
+<code>#length-negative</code> features.</p>
+</note>
+</div3>
+<div3 id="feature-length-integer">
+<head>#length-integer</head>
+<p>A TTML transformation processor supports the
+<code>#length-integer</code> feature if it recognizes and is
+capable of transforming integer values of the <loc
+href="#style-value-length">&lt;length&gt;</loc> style value
+expression.</p>
+<p>A TTML presentation processor supports the
+<code>#length-integer</code> feature if it implements presentation semantic
+support for integer values of the <loc
+href="#style-value-length">&lt;length&gt;</loc> style value
+expression.
+</p>
+<note role="clarification">
+<p>Support for <code>#length-integer</code> does not, by itself, imply support for
+<code>#length-positive</code> or
+<code>#length-negative</code> features.</p>
+</note>
+</div3>
+<div3 id="feature-length-negative">
+<head>#length-negative</head>
+<p>A TTML transformation processor supports the
+<code>#length-negative</code> feature if it recognizes and is
+capable of transforming negative values of the <loc
+href="#style-value-length">&lt;length&gt;</loc> style value
+expression.</p>
+<p>A TTML presentation processor supports the
+<code>#length-negative</code> feature if it implements presentation semantic
+support for negative values of the <loc
+href="#style-value-length">&lt;length&gt;</loc> style value
+expression.
+</p>
+<note role="clarification">
+<p>Support for <code>#length-negative</code> does not, by itself, imply support for
+<code>#length-integer</code> or
+<code>#length-real</code> features.</p>
+</note>
+</div3>
+<div3 id="feature-length-percentage">
+<head>#length-percentage</head>
+<p>A TTML transformation processor supports the
+<code>#length-percentage</code> feature if it recognizes and is
+capable of transforming percentage values of the <loc
+href="#style-value-length">&lt;length&gt;</loc> style value
+expression.</p>
+<p>A TTML presentation processor supports the
+<code>#length-percentage</code> feature if it implements presentation semantic
+support for percentage values of the <loc
+href="#style-value-length">&lt;length&gt;</loc> style value
+expression.
+</p>
+<note role="clarification">
+<p>Support for <code>#length-percentage</code> does not, by itself, imply support for
+<code>#length-integer</code>,
+<code>#length-real</code>,
+<code>#length-positive</code>, or
+<code>#length-negative</code> features.</p>
+</note>
+</div3>
+<div3 id="feature-length-pixel">
+<head>#length-pixel</head>
+<p>A TTML transformation processor supports the
+<code>#length-pixel</code> feature if it recognizes and is capable of
+transforming scalar values of the <loc
+href="#style-value-length">&lt;length&gt;</loc> style value expression
+that use <code>px</code> (pixel) units.</p>
+<p>A TTML presentation processor supports the
+<code>#length-pixel</code> feature if it implements presentation semantic support
+for scalar values of the <loc
+href="#style-value-length">&lt;length&gt;</loc> style value expression
+that use <code>px</code> (pixel) units.</p>
+<note role="clarification">
+<p>Support for <code>#length-pixel</code> does not, by itself, imply support for
+<code>#length-integer</code>,
+<code>#length-real</code>,
+<code>#length-positive</code>, or
+<code>#length-negative</code> features.</p>
+</note>
+</div3>
+<div3 id="feature-length-positive">
+<head>#length-positive</head>
+<p>A TTML transformation processor supports the
+<code>#length-positive</code> feature if it recognizes and is
+capable of transforming positive values of the <loc
+href="#style-value-length">&lt;length&gt;</loc> style value
+expression.</p>
+<p>A TTML presentation processor supports the
+<code>#length-positive</code> feature if it implements presentation semantic
+support for positive values of the <loc
+href="#style-value-length">&lt;length&gt;</loc> style value
+expression.
+</p>
+<note role="clarification">
+<p>Support for <code>#length-positive</code> is intended to imply support for zero valued
+<loc
+href="#style-value-length">&lt;length&gt;</loc> style value
+expressions.</p>
+</note>
+<note role="clarification">
+<p>Support for <code>#length-positive</code> does not, by itself, imply support for
+<code>#length-integer</code> or
+<code>#length-real</code> features.</p>
+</note>
+</div3>
+<div3 id="feature-length-real">
+<head>#length-real</head>
+<p>A TTML transformation processor supports the
+<code>#length-real</code> feature if it recognizes and is
+capable of transforming real values of the <loc
+href="#style-value-length">&lt;length&gt;</loc> style value
+expression.</p>
+<p>A TTML presentation processor supports the
+<code>#length-real</code> feature if it implements presentation semantic
+support for real values of the <loc
+href="#style-value-length">&lt;length&gt;</loc> style value
+expression.
+</p>
+<note role="clarification">
+<p>Support for <code>#length-real</code> is intended to imply support for
+integer valued <loc
+href="#style-value-length">&lt;length&gt;</loc> style value
+expressions as well as real valued expressions.</p>
+</note>
+<note role="clarification">
+<p>Support for <code>#length-real</code> does not, by itself, imply support for
+<code>#length-positive</code> or
+<code>#length-negative</code> features.</p>
+</note>
+</div3>
+<div3 id="feature-lineBreak-uax14">
+<head>#lineBreak-uax14</head>
+<p>A TTML transformation processor supports the
+<code>#lineBreak-uax14</code> feature if it recognizes and is capable of
+transforming requirements expressed by <bibref ref="uax14"/> into its
+target document space.</p>
+<p>A TTML presentation processor supports the
+<code>#lineBreak-uax14</code> feature if it implements presentation semantic support
+for <bibref ref="uax14"/> as applies to line breaking.</p>
+</div3>
+<div3 id="feature-lineHeight">
+<head>#lineHeight</head>
+<p>A TTML transformation processor supports the
+<code>#lineHeight</code> feature if it recognizes and is capable of
+transforming the <loc
+href="#style-attribute-lineHeight"><att>tts:lineHeight</att></loc>
+attribute.</p>
+<p>A TTML presentation processor supports the
+<code>#lineHeight</code> feature if it implements presentation semantic support for
+the <loc
+href="#style-attribute-lineHeight"><att>tts:lineHeight</att></loc>
+attribute.</p>
+</div3>
+<div3 id="feature-markerMode">
+<head>#markerMode</head>
+<p>A TTML transformation processor supports the
+<code>#markerMode</code> feature if it recognizes and is capable of
+transforming the <loc
+href="#parameter-attribute-markerMode"><att>ttp:markerMode</att></loc>
+attribute.</p>
+<p>A TTML presentation processor supports the
+<code>#markerMode</code> feature if it implements presentation semantic support
+for the <loc
+href="#parameter-attribute-markerMode"><att>ttp:markerMode</att></loc>
+attribute.</p>
+</div3>
+<div3 id="feature-markerMode-continuous">
+<head>#markerMode-continuous</head>
+<p>A TTML transformation processor supports the
+<code>#markerMode-continuous</code> feature if it recognizes and is capable of
+transforming the <code>continuous</code> value of the <loc
+href="#parameter-attribute-markerMode"><att>ttp:markerMode</att></loc>
+attribute.</p>
+<p>A TTML presentation processor supports the
+<code>#markerMode-continuous</code> feature if it implements presentation semantic support
+for the <code>continuous</code> value of the <loc
+href="#parameter-attribute-markerMode"><att>ttp:markerMode</att></loc>
+attribute.</p>
+</div3>
+<div3 id="feature-markerMode-discontinuous">
+<head>#markerMode-discontinuous</head>
+<p>A TTML transformation processor supports the
+<code>#markerMode-discontinuous</code> feature if it recognizes and is capable of
+transforming the <code>discontinuous</code> value of the <loc
+href="#parameter-attribute-markerMode"><att>ttp:markerMode</att></loc>
+attribute.</p>
+<p>A TTML presentation processor supports the
+<code>#markerMode-discontinuous</code> feature if it implements presentation semantic support
+for the <code>discontinuous</code> value of the <loc
+href="#parameter-attribute-markerMode"><att>ttp:markerMode</att></loc>
+attribute.</p>
+</div3>
+<div3 id="feature-metadata">
+<head>#metadata</head>
+<p>A TTML transformation processor supports the <code>#metadata</code>
+feature if it recognizes and is capable of transforming the following
+vocabulary defined by <specref ref="metadata"/>:</p>
+<ulist>
+<item><p><loc href="#metadata-vocabulary-metadata"><el>metadata</el></loc></p></item>
+<item><p><loc href="#metadata-vocabulary-title"><el>ttm:title</el></loc></p></item>
+<item><p><loc href="#metadata-vocabulary-title"><el>ttm:desc</el></loc></p></item>
+<item><p><loc href="#metadata-vocabulary-title"><el>ttm:copyright</el></loc></p></item>
+<item><p><loc href="#metadata-vocabulary-title"><el>ttm:agent</el></loc></p></item>
+<item><p><loc href="#metadata-vocabulary-title"><el>ttm:name</el></loc></p></item>
+<item><p><loc href="#metadata-vocabulary-title"><el>ttm:actor</el></loc></p></item>
+<item><p><loc href="#metadata-attribute-agent">@<att>ttm:agent</att></loc></p></item>
+<item><p><loc href="#metadata-attribute-role">@<att>ttm:role</att></loc></p></item>
+</ulist>
+<p>A TTML presentation processor supports the <code>#metadata</code>
+feature if it recognizes and is capable of presenting the information
+expressed by the same vocabulary enumerated above.</p>
+<note role="clarification">
+<p>This specification does not define a standardized form for the
+presentation of metadata information. The presentation or ability to
+present metadata information is considered to be implementation
+dependent.</p>
+</note>
+</div3>
+<div3 id="feature-nested-div">
+<head>#nested-div</head>
+<p>A TTML transformation processor supports the <code>#nested-div</code>
+feature if it recognizes and is capable of transforming nested
+<loc href="#content-vocabulary-div"><el>div</el></loc> elements.</p>
+<p>A TTML presentation processor supports the <code>#nested-div</code>
+feature if it implements presentation semantic support for nested
+<loc href="#content-vocabulary-div"><el>div</el></loc> elements.</p>
+</div3>
+<div3 id="feature-nested-span">
+<head>#nested-span</head>
+<p>A TTML transformation processor supports the <code>#nested-span</code>
+feature if it recognizes and is capable of transforming nested
+<loc href="#content-vocabulary-span"><el>span</el></loc> elements.</p>
+<p>A TTML presentation processor supports the <code>#nested-span</code>
+feature if it implements presentation semantic support for nested
+<loc href="#content-vocabulary-span"><el>span</el></loc> elements.</p>
+</div3>
+<div3 id="feature-opacity">
+<head>#opacity</head>
+<p>A TTML transformation processor supports the
+<code>#opacity</code> feature if it recognizes and is capable of
+transforming the <loc
+href="#style-attribute-opacity"><att>tts:opacity</att></loc>
+attribute.</p>
+<p>A TTML presentation processor supports the
+<code>#opacity</code> feature if it (1) implements presentation semantic support for
+the <loc
+href="#style-attribute-opacity"><att>tts:opacity</att></loc>
+attribute and (2) is capable of displaying or generating an output display
+signal that distinguishes between at least eight (8) values of opacity.</p>
+</div3>
+<div3 id="feature-origin">
+<head>#origin</head>
+<p>A TTML transformation processor supports the
+<code>#origin</code> feature if it recognizes and is capable of
+transforming the <loc
+href="#style-attribute-origin"><att>tts:origin</att></loc>
+attribute.</p>
+<p>A TTML presentation processor supports the
+<code>#origin</code> feature if it implements presentation semantic support for
+the <loc
+href="#style-attribute-origin"><att>tts:origin</att></loc>
+attribute.</p>
+</div3>
+<div3 id="feature-overflow">
+<head>#overflow</head>
+<p>A TTML transformation processor supports the
+<code>#overflow</code> feature if it recognizes and is capable of
+transforming all defined values of the <loc
+href="#style-attribute-overflow"><att>tts:overflow</att></loc>
+attribute.</p>
+<p>A TTML presentation processor supports the
+<code>#overflow</code> feature if it implements presentation semantic support for
+all defined values of the <loc
+href="#style-attribute-overflow"><att>tts:overflow</att></loc>
+attribute.</p>
+</div3>
+<div3 id="feature-overflow-visible">
+<head>#overflow-visible</head>
+<p>A TTML transformation processor supports the
+<code>#overflow-visible</code> feature if it recognizes and is capable of
+transforming the <code>visible</code> value of the <loc
+href="#style-attribute-overflow"><att>tts:overflow</att></loc>
+attribute.</p>
+<p>A TTML presentation processor supports the
+<code>#overflow-visible</code> feature if it implements presentation semantic support for
+the <code>visible</code> value of the <loc
+href="#style-attribute-overflow"><att>tts:overflow</att></loc>
+attribute.</p>
+</div3>
+<div3 id="feature-padding">
+<head>#padding</head>
+<p>A TTML transformation processor supports the
+<code>#padding</code> feature if it recognizes and is capable of
+transforming the <loc
+href="#style-attribute-padding"><att>tts:padding</att></loc>
+attribute.</p>
+<p>A TTML presentation processor supports the
+<code>#padding</code> feature if it implements presentation semantic support for
+the <loc
+href="#style-attribute-padding"><att>tts:padding</att></loc>
+attribute.</p>
+</div3>
+<div3 id="feature-padding-1">
+<head>#padding-1</head>
+<p>A TTML transformation processor supports the
+<code>#padding-1</code> feature if it recognizes and is capable of
+transforming values of the <loc
+href="#style-attribute-padding"><att>tts:padding</att></loc> attribute
+that consist of one <loc
+href="#style-value-length">&lt;length&gt;</loc> specification.</p>
+<p>A TTML presentation processor supports the <code>#padding-1</code>
+feature if it implements presentation semantic support for values of the <loc
+href="#style-attribute-padding"><att>tts:padding</att></loc> attribute
+that consist of one <loc
+href="#style-value-length">&lt;length&gt;</loc> specification.</p>
+</div3>
+<div3 id="feature-padding-2">
+<head>#padding-2</head>
+<p>A TTML transformation processor supports the
+<code>#padding-2</code> feature if it recognizes and is capable of
+transforming values of the <loc
+href="#style-attribute-padding"><att>tts:padding</att></loc> attribute
+that consist of two <loc
+href="#style-value-length">&lt;length&gt;</loc> specification.</p>
+<p>A TTML presentation processor supports the <code>#padding-2</code>
+feature if it implements presentation semantic support for values of the <loc
+href="#style-attribute-padding"><att>tts:padding</att></loc> attribute
+that consist of two <loc
+href="#style-value-length">&lt;length&gt;</loc> specification.</p>
+</div3>
+<div3 id="feature-padding-3">
+<head>#padding-3</head>
+<p>A TTML transformation processor supports the
+<code>#padding-3</code> feature if it recognizes and is capable of
+transforming values of the <loc
+href="#style-attribute-padding"><att>tts:padding</att></loc> attribute
+that consist of three <loc
+href="#style-value-length">&lt;length&gt;</loc> specification.</p>
+<p>A TTML presentation processor supports the <code>#padding-3</code>
+feature if it implements presentation semantic support for values of the <loc
+href="#style-attribute-padding"><att>tts:padding</att></loc> attribute
+that consist of three <loc
+href="#style-value-length">&lt;length&gt;</loc> specification.</p>
+</div3>
+<div3 id="feature-padding-4">
+<head>#padding-4</head>
+<p>A TTML transformation processor supports the
+<code>#padding-4</code> feature if it recognizes and is capable of
+transforming values of the <loc
+href="#style-attribute-padding"><att>tts:padding</att></loc> attribute
+that consist of four <loc
+href="#style-value-length">&lt;length&gt;</loc> specification.</p>
+<p>A TTML presentation processor supports the <code>#padding-4</code>
+feature if it implements presentation semantic support for values of the <loc
+href="#style-attribute-padding"><att>tts:padding</att></loc> attribute
+that consist of four <loc
+href="#style-value-length">&lt;length&gt;</loc> specification.</p>
+</div3>
+<div3 id="feature-pixelAspectRatio">
+<head>#pixelAspectRatio</head>
+<p>A TTML transformation processor supports the
+<code>#pixelAspectRatio</code> feature if it recognizes and is capable of
+transforming the <loc
+href="#parameter-attribute-pixelAspectRatio"><att>ttp:pixelAspectRatio</att></loc>
+attribute.</p>
+<p>A TTML presentation processor supports the
+<code>#pixelAspectRatio</code> feature if it implements presentation semantic support
+for the <loc
+href="#parameter-attribute-pixelAspectRatio"><att>ttp:pixelAspectRatio</att></loc>
+attribute.</p>
+</div3>
+<div3 id="feature-presentation">
+<head>#presentation</head>
+<p>A TTML processor supports the
+<code>#presentation</code> feature if it
+(1) satisfies the generic processor criteria defined by 
+<specref ref="conformance-generic-processor"/>,
+(2) implements support for the region and line layout
+semantics defined by <specref ref="semantics-region-layout"/> and
+<specref ref="semantics-line-layout"/>, respectively, and
+(3) implements presentation semantics for the following features:</p>
+<ulist>
+<item><p><loc href="#content"><code>#content</code></loc></p></item>
+<item><p><loc href="#feature-core"><code>#core</code></loc></p></item>
+<item><p><loc href="#feature-profile"><code>#profile</code></loc></p></item>
+<item><p><loc href="#feature-structure"><code>#structure</code></loc></p></item>
+<item><p><loc href="#feature-time-offset"><code>#time-offset</code></loc></p></item>
+<item><p><loc href="#timing"><code>#timing</code></loc></p></item>
+</ulist>
+<p>
+In addition, a TTML processor that supports the
+<code>#presentation</code> feature should satisfy the user agent
+accessibility guidelines specified by <bibref ref="uaag"/>.</p>
+</div3>
+<div3 id="feature-profile">
+<head>#profile</head>
+<p>A TTML transformation processor supports the <code>#profile</code>
+feature if it recognizes and is capable of transforming the
+<loc href="#parameter-attribute-profile"><att>ttp:profile</att></loc>
+attribute on the <loc
+href="#document-structure-vocabulary-tt"><el>tt</el></loc> element and
+transforming the following vocabulary defined by
+<specref ref="parameter-element-vocabulary"/>:</p>
+<ulist>
+<item><p><loc
+href="#parameter-vocabulary-profile"><el>ttp:profile</el></loc></p></item>
+<item><p><loc
+href="#parameter-vocabulary-features"><el>ttp:features</el></loc></p></item>
+<item><p><loc
+href="#parameter-vocabulary-feature"><el>ttp:feature</el></loc></p></item>
+<item><p><loc
+href="#parameter-vocabulary-extensions"><el>ttp:extensions</el></loc></p></item>
+<item><p><loc
+href="#parameter-vocabulary-extension"><el>ttp:extension</el></loc></p></item>
+</ulist>
+<p>A TTML presentation processor supports the
+<code>#profile</code> feature if it implements presentation semantic support
+for the same vocabulary specified above.</p>
+</div3>
+<div3 id="feature-showBackground">
+<head>#showBackground</head>
+<p>A TTML transformation processor supports the
+<code>#showBackground</code> feature if it recognizes and is capable
+of transforming all defined values of the <loc
+href="#style-attribute-showBackground"><att>tts:showBackground</att></loc>
+attribute.</p>
+<p>A TTML presentation processor supports the
+<code>#showBackground</code> feature if it implements presentation semantic support
+for all defined values of the <loc
+href="#style-attribute-showBackground"><att>tts:showBackground</att></loc>
+attribute.</p>
+</div3>
+<div3 id="feature-structure">
+<head>#structure</head>
+<p>A TTML transformation processor supports the <code>#structure</code>
+feature if it recognizes and is capable of transforming the following
+vocabulary defined by <specref ref="content"/>:</p>
+<ulist>
+<item><p><loc href="#document-structure-vocabulary-tt"><el>tt</el></loc></p></item>
+<item><p><loc href="#document-structure-vocabulary-head"><el>head</el></loc></p></item>
+</ulist>
+<p>A TTML presentation processor supports the <code>#structure</code>
+feature if it implements presentation semantic support for the
+same vocabulary enumerated above.</p>
+</div3>
+<div3 id="feature-styling">
+<head>#styling</head>
+<p>A TTML transformation processor supports the <code>#styling</code>
+feature if it recognizes and is capable of transforming the following
+vocabulary defined by <specref ref="styling"/>:</p>
+<ulist>
+<item><p><loc href="#styling-vocabulary-styling"><el>styling</el></loc></p></item>
+<item><p><loc href="#styling-vocabulary-style"><el>style</el></loc></p></item>
+<item><p><loc href="#style-attribute-style">@<att>style</att></loc></p></item>
+</ulist>
+<p>A TTML presentation processor supports the <code>#styling</code>
+feature if it implements presentation semantic support for the
+same vocabulary enumerated above.</p>
+</div3>
+<div3 id="feature-styling-chained">
+<head>#styling-chained</head>
+<p>A TTML transformation processor supports the
+<code>#styling-chained</code> feature if it recognizes and is capable
+of transforming chained style association as defined by <specref
+ref="semantics-style-association-chained-referential"/>.</p>
+<p>A TTML presentation processor supports the
+<code>#styling-chained</code> feature if it implements presentation semantic
+support for chained style association as defined by <specref
+ref="semantics-style-association-chained-referential"/>.</p>
+</div3>
+<div3 id="feature-styling-inheritance-content">
+<head>#styling-inheritance-content</head>
+<p>A TTML transformation processor supports the
+<code>#styling-inheritance</code> feature if it recognizes and is
+capable of transforming content style inheritance as defined by
+<specref ref="semantics-style-inheritance-content"/>.</p>
+<p>A TTML presentation processor supports the
+<code>#styling-inheritance-content</code> feature if it implements
+presentation semantic support for content style inheritance as defined by <specref
+ref="semantics-style-inheritance-content"/>.</p>
+</div3>
+<div3 id="feature-styling-inheritance-region">
+<head>#styling-inheritance-region</head>
+<p>A TTML transformation processor supports the
+<code>#styling-inheritance</code> feature if it recognizes and is
+capable of transforming region style inheritance as defined by
+<specref ref="semantics-style-inheritance-region"/>.</p>
+<p>A TTML presentation processor supports the
+<code>#styling-inheritance-region</code> feature if it implements
+presentation semantic support for region style inheritance as defined by <specref
+ref="semantics-style-inheritance-region"/>.</p>
+</div3>
+<div3 id="feature-styling-inline">
+<head>#styling-inline</head>
+<p>A TTML transformation processor supports the
+<code>#styling-inline</code> feature if it recognizes and is capable
+of transforming inline style association as defined by <specref
+ref="semantics-style-association-inline"/>.</p>
+<p>A TTML presentation processor supports the
+<code>#styling-inline</code> feature if it implements presentation semantic support
+for inline style association as defined by <specref
+ref="semantics-style-association-inline"/>.</p>
+</div3>
+<div3 id="feature-styling-nested">
+<head>#styling-nested</head>
+<p>A TTML transformation processor supports the
+<code>#styling-nested</code> feature if it recognizes and is capable
+of transforming nested style association as defined by <specref
+ref="semantics-style-association-nested"/>.</p>
+<p>A TTML presentation processor supports the
+<code>#styling-nested</code> feature if it implements presentation semantic support
+for nested style association as defined by <specref
+ref="semantics-style-association-nested"/>.</p>
+</div3>
+<div3 id="feature-styling-referential">
+<head>#styling-referential</head>
+<p>A TTML transformation processor supports the
+<code>#styling-referential</code> feature if it recognizes and is capable
+of transforming referential style association as defined by <specref
+ref="semantics-style-association-referential"/>.</p>
+<p>A TTML presentation processor supports the
+<code>#styling-referential</code> feature if it implements presentation semantic
+support for referential style association as defined by <specref
+ref="semantics-style-association-referential"/>.</p>
+</div3>
+<div3 id="feature-subFrameRate">
+<head>#subFrameRate</head>
+<p>A TTML transformation processor supports the
+<code>#subFrameRate</code> feature if it recognizes and is capable of
+transforming the <loc
+href="#parameter-attribute-subFrameRate"><att>ttp:subFrameRate</att></loc>
+attribute.</p>
+<p>A TTML presentation processor supports the
+<code>#subFrameRate</code> feature if it implements presentation semantic support
+for the <loc
+href="#parameter-attribute-subFrameRate"><att>ttp:subFrameRate</att></loc>
+attribute.</p>
+</div3>
+<div3 id="feature-textAlign">
+<head>#textAlign</head>
+<p>A TTML transformation processor supports the
+<code>#textAlign</code> feature if it recognizes and is capable
+of transforming all defined values of the <loc
+href="#style-attribute-textAlign"><att>tts:textAlign</att></loc>
+attribute.</p>
+<p>A TTML presentation processor supports the
+<code>#textAlign</code> feature if it implements presentation semantic support
+for all defined values of the <loc
+href="#style-attribute-textAlign"><att>tts:textAlign</att></loc>
+attribute.</p>
+</div3>
+<div3 id="feature-textAlign-absolute">
+<head>#textAlign-absolute</head>
+<p>A TTML transformation processor supports the
+<code>#textAlign-absolute</code> feature if it recognizes and is
+capable of transforming the <code>left</code>, <code>center</code>,
+and <code>right</code> values of the <loc
+href="#style-attribute-textAlign"><att>tts:textAlign</att></loc>
+attribute.</p>
+<p>A TTML presentation processor supports the
+<code>#textAlign-absolute</code> feature if it implements presentation semantic
+support for the <code>left</code>, <code>center</code>, and
+<code>right</code> values of the <loc
+href="#style-attribute-textAlign"><att>tts:textAlign</att></loc>
+attribute.</p>
+</div3>
+<div3 id="feature-textAlign-relative">
+<head>#textAlign-relative</head>
+<p>A TTML transformation processor supports the
+<code>#textAlign-relative</code> feature if it recognizes and is
+capable of transforming the <code>start</code>, <code>center</code>,
+and <code>end</code> values of the <loc
+href="#style-attribute-textAlign"><att>tts:textAlign</att></loc>
+attribute.</p>
+<p>A TTML presentation processor supports the
+<code>#textAlign-relative</code> feature if it implements presentation semantic
+support for the <code>start</code>, <code>center</code>, and
+<code>end</code> values of the <loc
+href="#style-attribute-textAlign"><att>tts:textAlign</att></loc>
+attribute.</p>
+</div3>
+<div3 id="feature-textDecoration">
+<head>#textDecoration</head>
+<p>A TTML transformation processor supports the
+<code>#textDecoration</code> feature if it recognizes and is capable
+of transforming all defined values of the <loc
+href="#style-attribute-textDecoration"><att>tts:textDecoration</att></loc>
+attribute.</p>
+<p>A TTML presentation processor supports the
+<code>#textDecoration</code> feature if it implements presentation semantic support
+for all defined values of the <loc
+href="#style-attribute-textDecoration"><att>tts:textDecoration</att></loc>
+attribute.</p>
+</div3>
+<div3 id="feature-textDecoration-over">
+<head>#textDecoration-over</head>
+<p>A TTML transformation processor supports the
+<code>#textDecoration-over</code> feature if it recognizes and is
+capable of transforming the <code>overline</code> and
+<code>noOverline</code> values of the <loc
+href="#style-attribute-textDecoration"><att>tts:textDecoration</att></loc>
+attribute.</p>
+<p>A TTML presentation processor supports the
+<code>#textDecoration-over</code> feature if it implements
+presentation semantic support for the <code>overline</code> and
+<code>noOverline</code> values of the <loc
+href="#style-attribute-textDecoration"><att>tts:textDecoration</att></loc>
+attribute.</p>
+</div3>
+<div3 id="feature-textDecoration-through">
+<head>#textDecoration-through</head>
+<p>A TTML transformation processor supports the
+<code>#textDecoration-through</code> feature if it recognizes and is
+capable of transforming the <code>lineThrough</code> and
+<code>noLineThrough</code> values of the <loc
+href="#style-attribute-textDecoration"><att>tts:textDecoration</att></loc>
+attribute.</p>
+<p>A TTML presentation processor supports the
+<code>#textDecoration-through</code> feature if it implements
+presentation semantic support for the <code>lineThrough</code> and
+<code>noLineThrough</code> values of the <loc
+href="#style-attribute-textDecoration"><att>tts:textDecoration</att></loc>
+attribute.</p>
+</div3>
+<div3 id="feature-textDecoration-under">
+<head>#textDecoration-under</head>
+<p>A TTML transformation processor supports the
+<code>#textDecoration-under</code> feature if it recognizes and is
+capable of transforming the <code>underline</code> and
+<code>noUnderline</code> values of the <loc
+href="#style-attribute-textDecoration"><att>tts:textDecoration</att></loc>
+attribute.</p>
+<p>A TTML presentation processor supports the
+<code>#textDecoration-under</code> feature if it implements
+presentation semantic support for the <code>underline</code> and
+<code>noUnderline</code> values of the <loc
+href="#style-attribute-textDecoration"><att>tts:textDecoration</att></loc>
+attribute.</p>
+</div3>
+<div3 id="feature-textOutline">
+<head>#textOutline</head>
+<p>A TTML transformation processor supports the
+<code>#textOutline</code> feature if it recognizes and is capable of
+transforming the <loc
+href="#style-attribute-textOutline"><att>tts:textOutline</att></loc>
+attribute.</p>
+<p>A TTML presentation processor supports the
+<code>#textOutline</code> feature if it implements presentation semantic support
+for the <loc
+href="#style-attribute-textOutline"><att>tts:textOutline</att></loc>
+attribute.</p>
+</div3>
+<div3 id="feature-textOutline-blurred">
+<head>#textOutline-blurred</head>
+<p>A TTML transformation processor supports the
+<code>#textOutline-blurred</code> feature if it recognizes and is capable of
+transforming values of the <loc
+href="#style-attribute-textOutline"><att>tts:textOutline</att></loc>
+attribute that includes a blur radius specification.</p>
+<p>A TTML presentation processor supports the
+<code>#textOutline-blurred</code> feature if it implements presentation semantic support
+for values of the <loc
+href="#style-attribute-textOutline"><att>tts:textOutline</att></loc>
+attribute that includes a blur radius specification.</p>
+</div3>
+<div3 id="feature-textOutline-unblurred">
+<head>#textOutline-unblurred</head>
+<p>A TTML transformation processor supports the
+<code>#textOutline-unblurred</code> feature if it recognizes and is capable of
+transforming values of the <loc
+href="#style-attribute-textOutline"><att>tts:textOutline</att></loc>
+attribute that does not include a blur radius specification.</p>
+<p>A TTML presentation processor supports the
+<code>#textOutline-unblurred</code> feature if it implements presentation semantic support
+for values of the <loc
+href="#style-attribute-textOutline"><att>tts:textOutline</att></loc>
+attribute that does not include a blur radius specification.</p>
+</div3>
+<div3 id="feature-tickRate">
+<head>#tickRate</head>
+<p>A TTML transformation processor supports the
+<code>#tickRate</code> feature if it recognizes and is capable of
+transforming the <loc
+href="#parameter-attribute-tickRate"><att>ttp:tickRate</att></loc>
+attribute.</p>
+<p>A TTML presentation processor supports the
+<code>#tickRate</code> feature if it implements presentation semantic support
+for the <loc
+href="#parameter-attribute-tickRate"><att>ttp:tickRate</att></loc>
+attribute.</p>
+</div3>
+<div3 id="feature-timeBase-clock">
+<head>#timeBase-clock</head>
+<p>A TTML transformation processor supports the
+<code>#timeBase-clock</code> feature if it recognizes and is capable
+of transforming the <code>clock</code> value of the <loc
+href="#parameter-attribute-timeBase"><att>ttp:timeBase</att></loc>
+attribute and if it supports the <loc
+href="#feature-clockMode"><code>#clockMode</code></loc> feature.</p>
+<p>A TTML presentation processor supports the
+<code>#timeBase-clock</code> feature if it implements presentation
+semantic support for the <code>clock</code> value of the <loc
+href="#parameter-attribute-timeBase"><att>ttp:timeBase</att></loc>
+attribute and if it supports the <loc
+href="#feature-clockMode"><code>#clockMode</code></loc> feature.</p>
+</div3>
+<div3 id="feature-timeBase-media">
+<head>#timeBase-media</head>
+<p>A TTML transformation processor supports the
+<code>#timeBase-media</code> feature if it recognizes and is capable
+of transforming the <code>media</code> value of the <loc
+href="#parameter-attribute-timeBase"><att>ttp:timeBase</att></loc>
+attribute.</p>
+<p>A TTML presentation processor supports the
+<code>#timeBase-media</code> feature if it implements presentation
+semantic support for the <code>media</code> value of the <loc
+href="#parameter-attribute-timeBase"><att>ttp:timeBase</att></loc>
+attribute.</p>
+</div3>
+<div3 id="feature-timeBase-smpte">
+<head>#timeBase-smpte</head>
+<p>A TTML transformation processor supports the
+<code>#timeBase-smpte</code> feature if it recognizes and is capable
+of transforming the <code>smpte</code> value of the <loc
+href="#parameter-attribute-timeBase"><att>ttp:timeBase</att></loc>
+attribute and if it supports the <loc
+href="#feature-dropMode"><code>#dropMode</code></loc> feature.</p>
+<p>A TTML presentation processor supports the
+<code>#timeBase-smpte</code> feature if it implements presentation
+semantic support for the <code>smpte</code> value of the <loc
+href="#parameter-attribute-timeBase"><att>ttp:timeBase</att></loc>
+attribute and if it supports the <loc
+href="#feature-dropMode"><code>#dropMode</code></loc> feature.</p>
+</div3>
+<div3 id="feature-timeContainer">
+<head>#timeContainer</head>
+<p>A TTML transformation processor supports the
+<code>#timeContainer</code> feature if it recognizes and is capable of
+transforming the <loc
+href="#timing-attribute-timeContainer"><att>timeContainer</att></loc>
+attribute.</p>
+<p>A TTML presentation processor supports the
+<code>#timeContainer</code> feature if it implements presentation semantic support
+for the <loc
+href="#timing-attribute-timeContainer"><att>timeContainer</att></loc>
+attribute.</p>
+</div3>
+<div3 id="feature-time-clock">
+<head>#time-clock</head>
+<p>A TTML transformation processor supports the
+<code>#time-clock</code> feature if it recognizes and is capable of
+transforming all values of the <loc
+href="#timing-value-timeExpression">&lt;timeExpression&gt;</loc> that
+satisfy the following subset of time expression syntax:</p>
+<eg xml:space="preserve">
+&lt;timeExpression&gt;
+  : hours ":" minutes ":" seconds ( fraction )?
+</eg>
+<p>A TTML presentation processor supports the
+<code>#time-clock</code> feature if it implements presentation
+semantic support for the same syntax specified above.</p>
+</div3>
+<div3 id="feature-time-clock-with-frames">
+<head>#time-clock-with-frames</head>
+<p>A TTML transformation processor supports the
+<code>#time-clock-with-frames</code> feature if it supports the
+<loc href="#feature-frameRate"><code>#frameRate</code></loc>,
+<loc href="#feature-frameRateMultiplier"><code>#frameRateMultiplier</code></loc>, and
+<loc href="#feature-subFrameRate"><code>#subFrameRate</code></loc> features
+and if it recognizes and is capable of
+transforming all values of the <loc
+href="#timing-value-timeExpression">&lt;timeExpression&gt;</loc> that
+satisfy the following subset of time expression syntax:</p>
+<eg xml:space="preserve">
+&lt;timeExpression&gt;
+  : hours ":" minutes ":" seconds ( fraction | ":" frames ( "." sub-frames )? )?
+</eg>
+<p>A TTML presentation processor supports the
+<code>#time-clock-with-frames</code> feature if it implements
+presentation semantic support for the same features and syntax
+specified above.</p>
+</div3>
+<div3 id="feature-time-offset">
+<head>#time-offset</head>
+<p>A TTML transformation processor supports the
+<code>#time-offset</code> feature if it recognizes and is capable of
+transforming all values of the <loc
+href="#timing-value-timeExpression">&lt;timeExpression&gt;</loc> that
+satisfy the following subset of time expression syntax:</p>
+<eg xml:space="preserve">
+&lt;timeExpression&gt;
+  : time-count fraction? ( "h" | "m" | "s" | "ms" )
+</eg>
+<p>A TTML presentation processor supports the
+<code>#time-offset</code> feature if it implements presentation
+semantic support for the same syntax specified above.</p>
+</div3>
+<div3 id="feature-time-offset-with-frames">
+<head>#time-offset-with-frames</head>
+<p>A TTML transformation processor supports the
+<code>#time-offset-with-frames</code> feature if it supports the
+<loc href="#feature-frameRate"><code>#frameRate</code></loc>,
+<loc href="#feature-frameRateMultiplier"><code>#frameRateMultiplier</code></loc>, and
+<loc href="#feature-subFrameRate"><code>#subFrameRate</code></loc> features
+and if it recognizes and is capable of
+transforming all values of the <loc
+href="#timing-value-timeExpression">&lt;timeExpression&gt;</loc> that
+satisfy the following subset of time expression syntax:</p>
+<eg xml:space="preserve">
+&lt;timeExpression&gt;
+  : time-count fraction? "f"
+</eg>
+<p>A TTML presentation processor supports the
+<code>#time-offset-with-frames</code> feature if it implements
+presentation semantic support for the same features and syntax
+specified above.</p>
+</div3>
+<div3 id="feature-time-offset-with-ticks">
+<head>#time-offset-with-ticks</head>
+<p>A TTML transformation processor supports the
+<code>#time-offset-with-ticks</code> feature if it supports the 
+<loc href="#feature-tickRate"><code>#tickRate</code></loc> feature
+and if it recognizes and is capable of
+transforming all values of the <loc
+href="#timing-value-timeExpression">&lt;timeExpression&gt;</loc> that
+satisfy the following subset of time expression syntax:</p>
+<eg xml:space="preserve">
+&lt;timeExpression&gt;
+  : time-count fraction? "t"
+</eg>
+<p>A TTML presentation processor supports the
+<code>#time-offset-with-ticks</code> feature if it implements presentation
+semantic support for the same features and syntax specified above.</p>
+</div3>
+<div3 id="feature-timing">
+<head>#timing</head>
+<p>A TTML transformation processor supports the <code>#timing</code>
+feature if it recognizes and is capable of transforming the following
+vocabulary defined by <specref ref="timing"/>:</p>
+<ulist>
+<item><p><loc href="#timing-attribute-begin">@<att>begin</att></loc></p></item>
+<item><p><loc href="#timing-attribute-dur">@<att>dur</att></loc></p></item>
+<item><p><loc href="#timing-attribute-end">@<att>end</att></loc></p></item>
+</ulist>
+<p>A TTML presentation processor supports the <code>#timing</code>
+feature if it implements presentation semantic support for the
+same vocabulary enumerated above.</p>
+</div3>
+<div3 id="feature-transformation">
+<head>#transformation</head>
+<p>A TTML processor supports the
+<code>#transformation</code> feature if it
+(1) satisfies the generic processor criteria defined by 
+<specref ref="conformance-generic-processor"/> and
+(2) implements the transformation semantics of the following features:</p>
+<ulist>
+<item><p><loc href="#content"><code>#content</code></loc></p></item>
+<item><p><loc href="#feature-core"><code>#core</code></loc></p></item>
+<item><p><loc href="#feature-profile"><code>#profile</code></loc></p></item>
+<item><p><loc href="#feature-structure"><code>#structure</code></loc></p></item>
+<item><p><loc href="#feature-time-offset"><code>#time-offset</code></loc></p></item>
+<item><p><loc href="#timing"><code>#timing</code></loc></p></item>
+</ulist>
+</div3>
+<div3 id="feature-unicodeBidi">
+<head>#unicodeBidi</head>
+<p>A TTML transformation processor supports the
+<code>#unicodeBidi</code> feature if it recognizes and is capable of
+transforming all defined values of the <loc
+href="#style-attribute-unicodeBidi"><att>tts:unicodeBidi</att></loc>
+attribute.</p>
+<p>A TTML presentation processor supports the
+<code>#unicodeBidi</code> feature if it implements presentation semantic support
+for all defined values of the <loc
+href="#style-attribute-unicodeBidi"><att>tts:unicodeBidi</att></loc>
+attribute.</p>
+</div3>
+<div3 id="feature-visibility">
+<head>#visibility</head>
+<p>A TTML transformation processor supports the
+<code>#visibility</code> feature if it recognizes and is capable
+of transforming all defined values of the <loc
+href="#style-attribute-visibility"><att>tts:visibility</att></loc>
+attribute.</p>
+<p>A TTML presentation processor supports the
+<code>#visibility</code> feature if it implements presentation semantic support
+for all defined values of the <loc
+href="#style-attribute-visibility"><att>tts:visibility</att></loc>
+attribute.</p>
+</div3>
+<div3 id="feature-visibility-block">
+<head>#visibility-block</head>
+<p>A TTML transformation processor supports the
+<code>#visibility-block</code> feature if it recognizes and is
+capable of transforming all defined values of the <loc
+href="#style-attribute-visibility"><att>tts:visibility</att></loc>
+attribute when applied to a content element that would generate a
+block area during presentation processing.</p>
+<p>A TTML presentation processor supports the
+<code>#visibility-block</code> feature if it implements presentation semantic
+support for all defined values of the <loc
+href="#style-attribute-visibility"><att>tts:visibility</att></loc>
+attribute when applied to a content element that generates a
+block area.</p>
+</div3>
+<div3 id="feature-visibility-inline">
+<head>#visibility-inline</head>
+<p>A TTML transformation processor supports the
+<code>#visibility-inline</code> feature if it recognizes and is
+capable of transforming all defined values of the <loc
+href="#style-attribute-visibility"><att>tts:visibility</att></loc>
+attribute when applied to a content element that would generate an
+inline area during presentation processing.</p>
+<p>A TTML presentation processor supports the
+<code>#visibility-inline</code> feature if it implements presentation semantic
+support for all defined values of the <loc
+href="#style-attribute-visibility"><att>tts:visibility</att></loc>
+attribute when applied to a content element that generates an
+inline area.</p>
+</div3>
+<div3 id="feature-visibility-region">
+<head>#visibility-region</head>
+<p>A TTML transformation processor supports the
+<code>#visibility-region</code> feature if it recognizes and is
+capable of transforming all defined values of the <loc
+href="#style-attribute-visibility"><att>tts:visibility</att></loc>
+attribute when applied to a <loc
+href="#layout-vocabulary-region"><el>region</el></loc> element.</p>
+<p>A TTML presentation processor supports the
+<code>#visibility-region</code> feature if it implements presentation semantic
+support for all defined values of the <loc
+href="#style-attribute-visibility"><att>tts:visibility</att></loc>
+attribute when applied to a <loc
+href="#layout-vocabulary-region"><el>region</el></loc> element.</p>
+</div3>
+<div3 id="feature-wrapOption">
+<head>#wrapOption</head>
+<p>A TTML transformation processor supports the
+<code>#wrapOption</code> feature if it recognizes and is capable
+of transforming all defined values of the <loc
+href="#style-attribute-wrapOption"><att>tts:wrapOption</att></loc>
+attribute.</p>
+<p>A TTML presentation processor supports the
+<code>#wrapOption</code> feature if it implements presentation semantic support
+for all defined values of the <loc
+href="#style-attribute-wrapOption"><att>tts:wrapOption</att></loc>
+attribute.</p>
+</div3>
+<div3 id="feature-writingMode">
+<head>#writingMode</head>
+<p>A TTML transformation processor supports the
+<code>#writingMode</code> feature if it recognizes and is capable
+of transforming all defined values of the <loc
+href="#style-attribute-writingMode"><att>tts:writingMode</att></loc>
+attribute.</p>
+<p>A TTML presentation processor supports the
+<code>#writingMode</code> feature if it implements presentation semantic support
+for all defined values of the <loc
+href="#style-attribute-writingMode"><att>tts:writingMode</att></loc>
+attribute.</p>
+</div3>
+<div3 id="feature-writingMode-vertical">
+<head>#writingMode-vertical</head>
+<p>A TTML transformation processor supports the
+<code>#writingMode-vertical</code> feature if it recognizes and is
+capable of transforming the <code>tbrl</code>, <code>tblr</code>, and
+<code>tb</code> values of the <loc
+href="#style-attribute-writingMode"><att>tts:writingMode</att></loc>
+attribute.</p>
+<p>A TTML presentation processor supports the
+<code>#writingMode-vertical</code> feature if it implements presentation semantic
+support for the <code>tbrl</code>, <code>tblr</code>, and
+<code>tb</code> values of the <loc
+href="#style-attribute-writingMode"><att>tts:writingMode</att></loc>
+attribute.</p>
+</div3>
+<div3 id="feature-writingMode-horizontal">
+<head>#writingMode-horizontal</head>
+<p>A TTML transformation processor supports the
+<code>#writingMode-horizontal</code> feature if it recognizes and is
+capable of transforming the <code>lrtb</code>, <code>rltb</code>,
+<code>lr</code> and <code>rl</code> values of the <loc
+href="#style-attribute-writingMode"><att>tts:writingMode</att></loc>
+attribute.</p>
+<p>A TTML presentation processor supports the
+<code>#writingMode-horizontal</code> feature if it implements presentation semantic
+support for the <code>lrtb</code>, <code>rltb</code>, <code>lr</code>
+and <code>rl</code> values of the <loc
+href="#style-attribute-writingMode"><att>tts:writingMode</att></loc>
+attribute.</p>
+</div3>
+<div3 id="feature-writingMode-horizontal-lr">
+<head>#writingMode-horizontal-lr</head>
+<p>A TTML transformation processor supports the
+<code>#writingMode-horizontal</code> feature if it recognizes and is
+capable of transforming the <code>lrtb</code> and <code>lr</code>
+values of the <loc
+href="#style-attribute-writingMode"><att>tts:writingMode</att></loc>
+attribute.</p>
+<p>A TTML presentation processor supports the
+<code>#writingMode-horizontal-lr</code> feature if it implements presentation semantic
+support for the <code>lrtb</code> and <code>lr</code> values of the
+<loc
+href="#style-attribute-writingMode"><att>tts:writingMode</att></loc>
+attribute.</p>
+</div3>
+<div3 id="feature-writingMode-horizontal-rl">
+<head>#writingMode-horizontal-rl</head>
+<p>A TTML transformation processor supports the
+<code>#writingMode-horizontal</code> feature if it recognizes and is
+capable of transforming the <code>rltb</code> and <code>rl</code>
+values of the <loc
+href="#style-attribute-writingMode"><att>tts:writingMode</att></loc>
+attribute.</p>
+<p>A TTML presentation processor supports the
+<code>#writingMode-horizontal-rl</code> feature if it implements presentation semantic
+support for the <code>rltb</code> and <code>rl</code> values of the
+<loc
+href="#style-attribute-writingMode"><att>tts:writingMode</att></loc>
+attribute.</p>
+</div3>
+<div3 id="feature-zIndex">
+<head>#zIndex</head>
+<p>A TTML transformation processor supports the
+<code>#zIndex</code> feature if it recognizes and is capable of
+transforming the <loc
+href="#style-attribute-zIndex"><att>tts:zIndex</att></loc>
+attribute.</p>
+<p>A TTML presentation processor supports the
+<code>#zIndex</code> feature if it implements presentation semantic support for
+the <loc
+href="#style-attribute-zIndex"><att>tts:zIndex</att></loc>
+attribute.</p>
+</div3>
+</div2>
+<div2 id="feature-support">
+<head>Feature Support</head>
+<p>The following table, <specref ref="feature-support-table"/>,
+enumerates every defined feature designation (expressed without the TT
+Feature Namespace), and, for each designated feature, specifies
+whether the feature must be implemented, i.e., is mandatory (M), or may be implemented, i.e.,
+is optional (O), for transformation and presentation processors.</p>
+<table id="feature-support-table" role="common">
+<caption>Table D-1 &ndash; Feature Support</caption>
+<col width="60%"/>
+<col width="20%"/>
+<col width="20%"/>
+<tbody>
+<tr>
+<td><phrase role="strong">Feature</phrase></td>
+<td><phrase role="strong">Transformation</phrase></td>
+<td><phrase role="strong">Presentation</phrase></td>
+</tr>
+<tr>
+<td><loc href="#feature-animation"><code>#animation</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-backgroundColor"><code>#backgroundColor</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-backgroundColor-block"><code>#backgroundColor-block</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-backgroundColor-inline"><code>#backgroundColor-inline</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-backgroundColor-region"><code>#backgroundColor-region</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-bidi"><code>#bidi</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-cellResolution"><code>#cellResolution</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-clockMode"><code>#clockMode</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-clockMode-gps"><code>#clockMode-gps</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-clockMode-local"><code>#clockMode-local</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-clockMode-utc"><code>#clockMode-utc</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-color"><code>#color</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-content"><code>#content</code></loc></td>
+<td>M</td>
+<td>M</td>
+</tr>
+<tr>
+<td><loc href="#feature-core"><code>#core</code></loc></td>
+<td>M</td>
+<td>M</td>
+</tr>
+<tr>
+<td><loc href="#feature-direction"><code>#direction</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-display"><code>#display</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-display-block"><code>#display-block</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-display-inline"><code>#display-inline</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-display-region"><code>#display-region</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-displayAlign"><code>#displayAlign</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-dropMode"><code>#dropMode</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-dropMode-dropNTSC"><code>#dropMode-dropNTSC</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-dropMode-dropPAL"><code>#dropMode-dropPAL</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-dropMode-nonDrop"><code>#dropMode-nonDrop</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-extent"><code>#extent</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-extent-region"><code>#extent-region</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-extent-root"><code>#extent-root</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-fontFamily"><code>#fontFamily</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-fontFamily-generic"><code>#fontFamily-generic</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-fontFamily-non-generic"><code>#fontFamily-non-generic</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-fontSize"><code>#fontSize</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-fontSize-anamorphic"><code>#fontSize-anamorphic</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-fontSize-isomorphic"><code>#fontSize-isomorphic</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-fontStyle"><code>#fontStyle</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-fontStyle-italic"><code>#fontStyle-italic</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-fontStyle-oblique"><code>#fontStyle-oblique</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-fontWeight"><code>#fontWeight</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-fontWeight-bold"><code>#fontWeight-bold</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-frameRate"><code>#frameRate</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-frameRateMultiplier"><code>#frameRateMultiplier</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-layout"><code>#layout</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-length"><code>#length</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-length-cell"><code>#length-cell</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-length-em"><code>#length-em</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-length-integer"><code>#length-integer</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-length-negative"><code>#length-negative</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-length-percentage"><code>#length-percentage</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-length-pixel"><code>#length-pixel</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-length-positive"><code>#length-positive</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-length-real"><code>#length-real</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-lineBreak-uax14"><code>#lineBreak-uax14</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-lineHeight"><code>#lineHeight</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-markerMode"><code>#markerMode</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-markerMode-continuous"><code>#markerMode-continuous</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-markerMode-discontinuous"><code>#markerMode-discontinuous</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-metadata"><code>#metadata</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-nested-div"><code>#nested-div</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-nested-span"><code>#nested-span</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-opacity"><code>#opacity</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-origin"><code>#origin</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-overflow"><code>#overflow</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-overflow-visible"><code>#overflow-visible</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-padding"><code>#padding</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-padding-1"><code>#padding-1</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-padding-2"><code>#padding-2</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-padding-3"><code>#padding-3</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-padding-4"><code>#padding-4</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-pixelAspectRatio"><code>#pixelAspectRatio</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-presentation"><code>#presentation</code></loc></td>
+<td>O</td>
+<td>M</td>
+</tr>
+<tr>
+<td><loc href="#feature-profile"><code>#profile</code></loc></td>
+<td>M</td>
+<td>M</td>
+</tr>
+<tr>
+<td><loc href="#feature-showBackground"><code>#showBackground</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-structure"><code>#structure</code></loc></td>
+<td>M</td>
+<td>M</td>
+</tr>
+<tr>
+<td><loc href="#feature-styling"><code>#styling</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-styling-chained"><code>#styling-chained</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-styling-inheritance-content"><code>#styling-inheritance-content</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-styling-inheritance-region"><code>#styling-inheritance-region</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-styling-inline"><code>#styling-inline</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-styling-nested"><code>#styling-nested</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-styling-referential"><code>#styling-referential</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-subFrameRate"><code>#subFrameRate</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-textAlign"><code>#textAlign</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-textAlign-absolute"><code>#textAlign-absolute</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-textAlign-relative"><code>#textAlign-relative</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-textDecoration"><code>#textDecoration</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-textDecoration-over"><code>#textDecoration-over</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-textDecoration-through"><code>#textDecoration-through</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-textDecoration-under"><code>#textDecoration-under</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-textOutline"><code>#textOutline</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-textOutline-blurred"><code>#textOutline-blurred</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-textOutline-unblurred"><code>#textOutline-unblurred</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-tickRate"><code>#tickRate</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-timeBase-clock"><code>#timeBase-clock</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-timeBase-media"><code>#timeBase-media</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-timeBase-smpte"><code>#timeBase-smpte</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-timeContainer"><code>#timeContainer</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-time-clock"><code>#time-clock</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-time-clock-with-frames"><code>#time-clock-with-frames</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-time-offset"><code>#time-offset</code></loc></td>
+<td>M</td>
+<td>M</td>
+</tr>
+<tr>
+<td><loc href="#feature-time-offset-with-frames"><code>#time-offset-with-frames</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-time-offset-with-ticks"><code>#time-offset-with-ticks</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-timing"><code>#timing</code></loc></td>
+<td>M</td>
+<td>M</td>
+</tr>
+<tr>
+<td><loc href="#feature-transformation"><code>#transformation</code></loc></td>
+<td>M</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-unicodeBidi"><code>#unicodeBidi</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-visibility"><code>#visibility</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-visibility-block"><code>#visibility-block</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-visibility-inline"><code>#visibility-inline</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-visibility-region"><code>#visibility-region</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-wrapOption"><code>#wrapOption</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-writingMode"><code>#writingMode</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-writingMode-vertical"><code>#writingMode-vertical</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-writingMode-horizontal"><code>#writingMode-horizontal</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-writingMode-horizontal-lr"><code>#writingMode-horizontal-lr</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-writingMode-horizontal-rl"><code>#writingMode-horizontal-rl</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+<tr>
+<td><loc href="#feature-zIndex"><code>#zIndex</code></loc></td>
+<td>O</td>
+<td>O</td>
+</tr>
+</tbody>
+</table>
+<p>For the sake of convenience, the following table,
+<specref ref="feature-transformation-mandatory-table"/>, enumerates all
+mandatory features for a TTML Transformation Processor, providing additional
+comments to summarize the context of usage or the nature of the feature.
+The <emph>Profile Definition Document</emph> that defines the corresponding
+DFXP Transformation Profile is specified in
+<specref ref="profile-dfxp-transformation"/>.
+</p>
+<table id="feature-transformation-mandatory-table" role="common">
+<caption>Table D-2 &ndash; Mandatory Features - Transformation</caption>
+<col width="60%"/>
+<col width="40%"/>
+<tbody>
+<tr>
+<td><phrase role="strong">Feature</phrase></td>
+<td><phrase role="strong">Comments</phrase></td>
+</tr>
+<tr>
+<td><loc href="#feature-content"><code>#content</code></loc></td>
+<td>
+<loc href="#document-structure-vocabulary-body"><el>body</el></loc>,
+<loc href="#content-vocabulary-div"><el>div</el></loc>,
+<loc href="#content-vocabulary-p"><el>p</el></loc>,
+<loc href="#content-vocabulary-span"><el>span</el></loc>,
+<loc href="#content-vocabulary-br"><el>br</el></loc>
+</td>
+</tr>
+<tr>
+<td><loc href="#feature-core"><code>#core</code></loc></td>
+<td>
+<loc href="#content-attribute-id">@<att>xml:id</att></loc>,
+<loc href="#content-attribute-id">@<att>xml:lang</att></loc>,
+<loc href="#content-attribute-id">@<att>xml:space</att></loc>
+</td>
+</tr>
+<tr>
+<td><loc href="#feature-profile"><code>#profile</code></loc></td>
+<td></td>
+</tr>
+<tr>
+<td><loc href="#feature-structure"><code>#structure</code></loc></td>
+<td>
+<loc href="#document-structure-vocabulary-tt"><el>tt</el></loc>,
+<loc href="#document-structure-vocabulary-head"><el>head</el></loc>
+</td>
+</tr>
+
+<tr>
+<td><loc href="#feature-time-offset"><code>#time-offset</code></loc></td>
+<td></td>
+</tr>
+<tr>
+<td><loc href="#feature-timing"><code>#timing</code></loc></td>
+<td>
+<loc href="#timing-attribute-begin">@<att>begin</att></loc>,
+<loc href="#timing-attribute-dur">@<att>dur</att></loc>,
+<loc href="#timing-attribute-end">@<att>end</att></loc>
+</td>
+</tr>
+<tr>
+<td><loc href="#feature-transformation"><code>#transformation</code></loc></td>
+<td></td>
+</tr>
+</tbody>
+</table>
+<p>For the sake of convenience, the following table,
+<specref ref="feature-presentation-mandatory-table"/>, enumerates all
+mandatory features for a TTML Presentation Processor, providing additional
+comments to summarize the context of usage or the nature of the feature.
+The <emph>Profile Definition Document</emph> that defines the corresponding
+DFXP Presentation Profile is specified in
+<specref ref="profile-dfxp-presentation"/>.
+</p>
+<table id="feature-presentation-mandatory-table" role="common">
+<caption>Table D-3 &ndash; Mandatory Features - Presentation</caption>
+<col width="60%"/>
+<col width="40%"/>
+<tbody>
+<tr>
+<td><phrase role="strong">Feature</phrase></td>
+<td><phrase role="strong">Comments</phrase></td>
+</tr>
+<tr>
+<td><loc href="#feature-content"><code>#content</code></loc></td>
+<td>
+<loc href="#document-structure-vocabulary-body"><el>body</el></loc>,
+<loc href="#content-vocabulary-div"><el>div</el></loc>,
+<loc href="#content-vocabulary-p"><el>p</el></loc>,
+<loc href="#content-vocabulary-span"><el>span</el></loc>,
+<loc href="#content-vocabulary-br"><el>br</el></loc>
+</td>
+</tr>
+<tr>
+<td><loc href="#feature-core"><code>#core</code></loc></td>
+<td>
+<loc href="#content-attribute-id">@<att>xml:id</att></loc>,
+<loc href="#content-attribute-id">@<att>xml:lang</att></loc>,
+<loc href="#content-attribute-id">@<att>xml:space</att></loc>
+</td>
+</tr>
+<tr>
+<td><loc href="#feature-profile"><code>#profile</code></loc></td>
+<td></td>
+</tr>
+<tr>
+<td><loc href="#feature-presentation"><code>#presentation</code></loc></td>
+<td></td>
+</tr>
+<tr>
+<td><loc href="#feature-structure"><code>#structure</code></loc></td>
+<td>
+<loc href="#document-structure-vocabulary-tt"><el>tt</el></loc>,
+<loc href="#document-structure-vocabulary-head"><el>head</el></loc>
+</td>
+</tr>
+<tr>
+<td><loc href="#feature-time-offset"><code>#time-offset</code></loc></td>
+<td></td>
+</tr>
+<tr>
+<td><loc href="#feature-timing"><code>#timing</code></loc></td>
+<td>
+<loc href="#timing-attribute-begin">@<att>begin</att></loc>,
+<loc href="#timing-attribute-dur">@<att>dur</att></loc>,
+<loc href="#timing-attribute-end">@<att>end</att></loc>
+</td>
+</tr>
+</tbody>
+</table>
+</div2>
+</div1>
+<div1 id="extensions">
+<head>Extensions</head>
+<p><emph>This appendix is normative.</emph></p>
+<p>This appendix specifies the syntactic form of extension designations, which are
+used to express authorial intent regarding the support for extension
+mechanisms in a TTML processor.</p>
+<div2 id="extension-designations">
+<head>Extension Designations</head>
+<p>An extension designation is expressed as a string that adheres to the following
+form:</p>
+<eg xml:space="preserve">
+extension-designation
+  : extension-namespace designation
+
+extension-namespace
+  : <emph>TT Extension Namespace</emph>                  // http://www.w3.org/ns/ttml/extension/
+  | <emph>Other Extension Namespace</emph>               // expressed as an absolute URI
+
+designation
+  : "#" token-char+
+
+token-char
+  : { XML NameChar }                        // XML 1.1 Production [4a]
+</eg>
+<p>If the extension namespace of an extension designation is the TT
+Extension Namespace, then all values of the following
+<code>designation</code> token are reserved for future
+standardization.</p>
+<p>If the extension namespace of an extension designation is not the
+TT Extension Namespace, i.e., is an <emph>Other Extension Namespace</emph>,
+then the extension namespace must be expressed as an absolute URI
+capable of serving as a base URI used in combination with a
+<code>designation</code> token that takes the form of a fragment
+identifier.</p>
+</div2>
+</div1>
+<div1 id="profiles">
+<head>Profiles</head>
+<p><emph>This appendix is normative.</emph></p>
+<p>This appendix specifies the following standard TTML profiles:</p>
+<ulist>
+<item><p><specref ref="profile-dfxp-transformation"/></p></item>
+<item><p><specref ref="profile-dfxp-presentation"/></p></item>
+<item><p><specref ref="profile-dfxp-full"/></p></item>
+</ulist>
+<p>The SDP US profile is defined in
+<xspecref href="http://www.w3.org/TR/ttml10-sdp-us/">TTML Simple Delivery Profile for Closed Captions (US)</xspecref>.</p>
+<p>Each TTML profile is defined in terms of a <emph>Profile Definition Document</emph>,
+which is expressed as an XML document wherein the root element adheres to
+<specref ref="parameter-vocabulary-profile"/>.</p>
+<div2 id="profile-dfxp-transformation">
+<head>DFXP Transformation Profile</head>
+<p>The DFXP Transformation Profile is intended to be used to
+express minimum compliance for transformation processing.</p>
+<eg xml:space="preserve">&profile-dfxp-transformation;</eg>
+</div2>
+<div2 id="profile-dfxp-presentation">
+<head>DFXP Presentation Profile</head>
+<p>The DFXP Presentation Profile is intended to be used to
+express minimum compliance for presentation processing.</p>
+<eg xml:space="preserve">&profile-dfxp-presentation;</eg>
+</div2>
+<div2 id="profile-dfxp-full">
+<head>DFXP Full Profile</head>
+<p>The DFXP Full Profile is intended to be used to
+express maximum compliance for both transformation and presentation processing.</p>
+<eg xml:space="preserve">&profile-dfxp-full;</eg>
+</div2>
+</div1>
+
+<div1 id="references">
+<head>References</head>
+<p><emph>This appendix is normative.</emph></p>
+<blist>
+<bibl id="css2" key="CSS2">Bert Bos et al.,
+<titleref
+href="http://www.w3.org/TR/2011/REC-CSS2-20110607/">Cascading
+Style Sheets, Level 2 Revision 1</titleref>, W3C Recommendation, 07 June 2011.
+(See <xspecref href="http://www.w3.org/TR/2011/REC-CSS2-20110607/">http://www.w3.org/TR/2011/REC-CSS2-20110607/</xspecref>.)
+</bibl>
+<bibl id="css3-color" key="CSS3 Color">Tantek &Ccedil;elik and Chris Lilley,
+<titleref href="http://www.w3.org/TR/2011/REC-css3-color-20110607/">CSS Color
+Module Level 3</titleref>, W3C Recommendation, 07 June 2011. (See
+<xspecref href="http://www.w3.org/TR/2011/REC-css3-color-20110607/">http://www.w3.org/TR/2011/REC-css3-color-20110607/</xspecref>.)
+</bibl>
+<bibl id="gps" key="GPS">
+<titleref href="http://tycho.usno.navy.mil/gpsinfo.html">Global
+Positioning System</titleref>, US Naval Observatory.
+(See
+<xspecref href="http://tycho.usno.navy.mil/gpsinfo.html">http://tycho.usno.navy.mil/gpsinfo.html</xspecref>.)
+</bibl>
+<bibl id="media-types" key="Media Types">Ned Freed and Nathaniel Borenstein,  
+<titleref
+href="http://www.rfc-editor.org/rfc/rfc2046.txt">Multipurpose Internet
+Mail Extensions (MIME) Part Two: Media Types</titleref>,
+RFC 2046, November 1996, IETF.(See
+<xspecref href="http://www.rfc-editor.org/rfc/rfc2046.txt">http://www.rfc-editor.org/rfc/rfc2046.txt</xspecref>.)
+</bibl>
+<bibl id="rng" key="RELAX NG">ISO/IEC 19757-2,
+<titleref href="http://www.iso.org/">Information technology &ndash; Document
+Schema Definition Language (DSDL) &ndash; Part 2: Regular-grammar-based validation &ndash; RELAX NG</titleref>,
+International Organization for Standardization (ISO).
+</bibl>
+<bibl id="smil21" key="SMIL 2.1">Dick Bultermann, et al.,
+<titleref href="http://www.w3.org/TR/2005/REC-SMIL2-20051213/">Synchronized
+Multimedia Integration Language (SMIL 2.1)</titleref>,
+W3C Recommendation, 13 December 2005. (See
+<xspecref href="http://www.w3.org/TR/2005/REC-SMIL2-20051213/">http://www.w3.org/TR/2005/REC-SMIL2-20051213/</xspecref>.)
+</bibl>
+<bibl id="smpte12m" key="SMPTE 12M">ANSI/SMPTE 12M,
+<titleref href="https://www.smpte.org/">Television, Audio and Film &ndash;
+Time and Control Code</titleref>, SMPTE Standard.
+</bibl>
+<bibl id="srgb" key="SRGB">IEC 61966-2-1,
+<titleref
+href="http://www.iec.ch/">Multimedia
+systems and equipment &ndash; Colour measurement and management
+&ndash; Part 2-1: Colour management &ndash; Default RGB colour space
+&ndash; sRGB</titleref>, International Electrotechnical
+Commission (IEC).
+</bibl>
+<bibl id="uaag" key="UAAG">Ian Jacobs, Jon Gunderson, and Eric Hansen, Eds.,
+<titleref href="http://www.w3.org/TR/2002/REC-UAAG10-20021217/">User
+Agent Accessibility Guidelines 1.0</titleref>, W3C Recommendation, 17
+December 2002. (See
+<xspecref href="http://www.w3.org/TR/2002/REC-UAAG10-20021217/">http://www.w3.org/TR/2002/REC-UAAG10-20021217/</xspecref>.)
+</bibl>
+<bibl id="uax14" key="UAX14">Asmus Freytag, <titleref
+href="http://www.unicode.org/reports/tr14/tr14-17.html">Line Breaking
+Properties</titleref>, Unicode Consortium, 29 August 2005. (See
+<xspecref
+href="http://www.unicode.org/reports/tr14/tr14-17.html">http://www.unicode.org/reports/tr14/tr14-17.html</xspecref>.)
+</bibl>
+<bibl id="utc" key="UTC">
+Recommendation TF.460,
+<titleref
+href="http://www.itu.int/">Standard-Frequency and Time-Signal
+Emissions</titleref>, International
+Telecommunciations Union, Radio Sector (ITU-R).
+</bibl>
+<bibl id="wcag" key="WCAG">Ben Caldwell, et al., Eds.,
+<titleref href="http://www.w3.org/TR/2008/REC-WCAG20-20081211/">Web
+Content Accessibility Guidelines (WCAG) 2.0</titleref>, W3C Recommendation, 11 December 2008. (See
+<xspecref href="http://www.w3.org/TR/2008/REC-WCAG20-20081211/">http://www.w3.org/TR/2008/REC-WCAG20-20081211/</xspecref>.)
+</bibl>
+<bibl id="xml10" key="XML 1.0">Tim Bray, et al.
+<titleref href="http://www.w3.org/TR/2008/REC-xml-20081126/">Extensible Markup Language (XML)
+1.0 (Fifth Edition)</titleref>, W3C Recommendation, 26 November 2008. (See
+<xspecref href="http://www.w3.org/TR/2008/REC-xml-20081126/">http://www.w3.org/TR/2008/REC-xml-20081126/</xspecref>.)
+</bibl>
+<bibl id="xml11" key="XML 1.1">Tim Bray, et al.
+<titleref href="http://www.w3.org/TR/2006/REC-xml11-20060816/">Extensible Markup Language (XML)
+1.1 (Second Edition)</titleref>, W3C Recommendation, 16 August 2006, edited in place 29 September 2006. (See
+<xspecref href="http://www.w3.org/TR/2006/REC-xml11-20060816/">http://www.w3.org/TR/2006/REC-xml11-20060816/</xspecref>.)
+</bibl>
+<bibl id="xmlbase" key="XML Base">Jonathan Marsh and Richard Tobin, Eds.,
+<titleref href="http://www.w3.org/TR/2009/REC-xmlbase-20090128/">XML Base (Second Edition)</titleref>,
+W3C Recommendation, 28 January 2009. (See
+<xspecref href="http://www.w3.org/TR/2009/REC-xmlbase-20090128/">http://www.w3.org/TR/2009/REC-xmlbase-20090128/</xspecref>.)
+</bibl>
+<bibl id="xmlid" key="XML ID">Jonathan Marsh, Daniel Veillard, Norman Walsh, Eds.,
+<titleref href="http://www.w3.org/TR/2005/REC-xml-id-20050909/">xml:id Version 1.0</titleref>,
+W3C Recommendation, 09 September 2005. (See
+<xspecref href="http://www.w3.org/TR/2005/REC-xml-id-20050909/">http://www.w3.org/TR/2005/REC-xml-id-20050909/</xspecref>.)
+</bibl>
+<bibl id="infoset" key="XML InfoSet">John Cowan and Richard Tobin, Eds.,
+<titleref href="http://www.w3.org/TR/2004/REC-xml-infoset-20040204/">XML Information Set (Second Edition)</titleref>,
+W3C Recommendation, 04 February 2004. (See
+<xspecref href="http://www.w3.org/TR/2004/REC-xml-infoset-20040204/">http://www.w3.org/TR/2004/REC-xml-infoset-20040204/</xspecref>.)
+</bibl>
+<bibl id="xml-media" key="XML Media Types">Makato Murata, Simon St. Laurent,
+Kan Khon, Eds., <titleref
+href="http://www.rfc-editor.org/rfc/rfc3023.txt">XML Media Types</titleref>,
+RFC 3023, January 2001, IETF.(See
+<xspecref
+href="http://www.rfc-editor.org/rfc/rfc3023.txt">http://www.rfc-editor.org/rfc/rfc3023.txt</xspecref>.)
+</bibl>
+<bibl id="xmlns10" key="XML Namespaces 1.0">Tim Bray, et al.
+<titleref href="http://www.w3.org/TR/2009/REC-xml-names-20091208/">Namespaces
+in XML 1.0 (Third Edition)</titleref>, W3C Recommendation, 8 December 2009. (See
+<xspecref href="http://www.w3.org/TR/2009/REC-xml-names-20091208/">http://www.w3.org/TR/2009/REC-xml-names-20091208/</xspecref>.)
+</bibl>
+<bibl id="xsd-1" key="XML Schema Part 1">Henry S. Thompson, David Beech,
+Murray Maloney, Noah Mendelsohn, Eds.,
+<titleref href="http://www.w3.org/TR/xmlschema-1/">XML Schema Part 1: Structures</titleref>,
+W3C Recommendation, 28 October 2004. (See
+<xspecref href="http://www.w3.org/TR/xmlschema-1/">http://www.w3.org/TR/xmlschema-1/</xspecref>.)
+</bibl>
+<bibl id="xsd-2" key="XML Schema Part 2">Paul Biron and Ashok Malhotra,
+<titleref href="http://www.w3.org/TR/xmlschema-2/">XML Schema Part 2: Datatypes</titleref>,
+W3C Recommendation, 28 October 2004. (See
+<xspecref href="http://www.w3.org/TR/xmlschema-2/">http://www.w3.org/TR/xmlschema-2/</xspecref>.)
+</bibl>
+<bibl id="xsl11" key="XSL 1.1">Anders Berglund,
+<titleref href="http://www.w3.org/TR/2006/REC-xsl11-20061205/">Extensible Stylesheet Language (XSL) Version 1.1</titleref>,
+W3C Recommendation, 05 December 2006. (See
+<xspecref href="http://www.w3.org/TR/2006/REC-xsl11-20061205/">http://www.w3.org/TR/2006/REC-xsl11-20061205/</xspecref>.)
+</bibl>
+</blist>
+</div1>
+<inform-div1 id="other-references">
+<head>Other References</head>
+<blist>
+<bibl id="ccreq" key="CC-DECODER-REQ"><titleref
+href="http://www.gpo.gov/fdsys/pkg/CFR-2005-title47-vol1/xml/CFR-2005-title47-vol1-sec15-119.xml">Closed Caption Decoder
+Requirements for Analog Television</titleref>,
+United States Code of Federal Regulations, Title 47, Volume 1, Part 15, &sect; 15.119. (See
+<xspecref href="http://www.gpo.gov/fdsys/pkg/CFR-2005-title47-vol1/xml/CFR-2005-title47-vol1-sec15-119.xml">http://www.gpo.gov/fdsys/pkg/CFR-2005-title47-vol1/xml/CFR-2005-title47-vol1-sec15-119.xml</xspecref>.)
+</bibl>
+<bibl id="cea608c" key="CEA-608-C">
+EIA/CEA-608-C,
+<titleref href="http://www.ce.org/">Line 21 Data
+Services</titleref>, EIA/CEA Standard,
+Consumer Electronics Association (CEA).
+</bibl>
+<bibl id="cea708d" key="CEA-708-D">
+CEA-708-D,
+<titleref href="http://www.ce.org/">Digital Television (DTV) Closed Captioning</titleref>, CEA Standard,
+Consumer Electronics Association (CEA).
+</bibl>
+<bibl id="dcmes" key="DCMES 1.1">Dublin Core Metadata Initiative,
+<titleref href="http://dublincore.org/documents/dces/">Dublin Core Metadata Element Set, Version 1.1: Reference Description</titleref>. (See
+<xspecref href="http://dublincore.org/documents/dces/">http://dublincore.org/documents/dces/</xspecref>.)
+</bibl>
+<bibl id="mpeg7-5" key="MPEG7-5">
+ISO/IEC 15938-5,
+<titleref
+href="http://www.iso.org/">Information technology &ndash; Multimedia content description
+interface &ndash; Part 5: Multimedia description schemes</titleref>,
+International Organization for Standardization (ISO).
+</bibl>
+<bibl id="nsstate" key="NSState">Norman Walsh, Ed.,
+<titleref
+href="http://www.w3.org/2001/tag/doc/namespaceState-2006-01-09.html">The Disposition
+of Names in an XML Namespace</titleref>, TAG Finding, 9 January 2006. (See
+<xspecref href="http://www.w3.org/2001/tag/doc/namespaceState-2006-01-09.html">http://www.w3.org/2001/tag/doc/namespaceState-2006-01-09</xspecref>.)
+</bibl>
+<bibl id="qaf-sg" key="QAF SG">Karl Dubost, et al.,
+<titleref
+href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/">QA
+Framework: Specifications Guidelines</titleref>, W3C Recommendation, 17
+August 2005. (See
+<xspecref href="http://www.w3.org/TR/qaframe-spec/">http://www.w3.org/TR/qaframe-spec/</xspecref>.)
+</bibl>
+<bibl id="smpte170m" key="SMPTE 170M">ANSI/SMPTE 170M, 
+<titleref
+href="http://www.smpte.org/">Television &ndash; Composite Analog Video
+Signal &ndash; NTSC for Studio Applications</titleref>, SMPTE Standard.
+</bibl>
+<bibl id="smpte2052" key="SMPTE 2052-11">SMPTE 2052-11,
+<titleref
+href="http://www.smpte.org/">Conversion from CEA-708 Caption Data to SMPTE-TT</titleref>,
+SMPTE Recommended Practice.
+</bibl>
+<bibl id="svg11" key="SVG 1.1">Jon Ferraiolo, Jun Fujisawa, Dean Jackson, Eds.,
+<titleref
+href="http://www.w3.org/TR/2003/REC-SVG11-20030114/">Scalable
+Vector Graphics (SVG) 1.1 Specification</titleref>, W3C Recommendation, 14
+January 2003. (See
+<xspecref href="http://www.w3.org/TR/2003/REC-SVG11-20030114/">http://www.w3.org/TR/2003/REC-SVG11-20030114/</xspecref>.)
+</bibl>
+<bibl id="ttaf1-req" key="TTAF1-REQ">Glenn Adams, Ed.,
+<titleref href="http://www.w3.org/TR/2006/NOTE-ttaf1-req-20060427/">Timed Text (TT) Authoring Format 1.0 Use
+Cases and Requirements</titleref>,
+W3C Working Group Note, 27 April 2006. (See
+<xspecref
+href="http://www.w3.org/TR/2006/NOTE-ttaf1-req-20060427/">http://www.w3.org/TR/2006/NOTE-ttaf1-req-20060427/</xspecref>.)
+</bibl>
+<bibl id="xhtml10" key="XHTML 1.0">Steven Pemberton, et al.,
+<titleref
+href="http://www.w3.org/TR/2002/REC-xhtml1-20020801/">XHTML&trade; 1.0,
+The Extensible Hypertext Markup Language (Second Edition)</titleref>,
+W3C Recommendation, 01
+August 2002. (See
+<xspecref href="http://www.w3.org/TR/2002/REC-xhtml1-20020801/">http://www.w3.org/TR/2002/REC-xhtml1-20020801/</xspecref>.)
+</bibl>
+</blist>
+</inform-div1>
+<inform-div1 id="requirements">
+<head>Requirements</head>
+<p>The Timed Text Markup Language (TTML), also known as the Distribution Format Exchange Profile (DFXP) of the Timed Text Authoring
+Format (TTAF), satisfies a subset of the requirements established by
+<bibref ref="ttaf1-req"/>. The following table enumerates these requirements and
+indicates the extent to which they are satisfied by this specification, where
+<emph>S</emph> denotes a requirement is satisfied, <emph>P</emph> denotes
+a requirement is partially satisfied, and <emph>N</emph> denotes a
+requirement is not satisfied.</p>
+<table id="requirements-table" role="common">
+<caption>Table I-1 &ndash; Requirement Satisfaction</caption>
+<col width="10%"/>
+<col width="40%"/>
+<col width="10%"/>
+<col/>
+<tbody>
+<tr>
+<th>ID</th>
+<th>Name</th>
+<th>Status</th>
+<th>Comments</th>
+</tr>
+<tr>
+<td>R100</td>
+<td>Specification Format</td>
+<td>S</td>
+<td/>
+</tr>
+<tr>
+<td>R101</td>
+<td>Specification Modularity</td>
+<td>S</td>
+<td/>
+</tr>
+<tr>
+<td>R102</td>
+<td>Specification Organization</td>
+<td>S</td>
+<td/>
+</tr>
+<tr>
+<td>R103</td>
+<td>Core and Periphery</td>
+<td>S</td>
+<td>TT extension namespaces</td>
+</tr>
+<tr>
+<td>R104</td>
+<td>Evolution of Core</td>
+<td>S</td>
+<td>TT extension namespaces</td>
+</tr>
+<tr>
+<td>R105</td>
+<td>Ownership of Core</td>
+<td>S</td>
+<td>TT namespaces</td>
+</tr>
+<tr>
+<td>R106</td>
+<td>Surjection of Core</td>
+<td>S</td>
+<td/>
+</tr>
+<tr>
+<td>R107</td>
+<td>Evolution of Periphery</td>
+<td>S</td>
+<td>TT extension namespaces</td>
+</tr>
+<tr>
+<td>R108</td>
+<td>Ownership of Periphery</td>
+<td>S</td>
+<td>Non-TT namespaces</td>
+</tr>
+<tr>
+<td>R109</td>
+<td>Transformation</td>
+<td>S</td>
+<td>Supports 3GPP, QText, RealText, SAMI</td>
+</tr>
+<tr>
+<td>R110</td>
+<td>Streamable Transformation</td>
+<td>S</td>
+<td>Progressive decoding</td>
+</tr>
+<tr>
+<td>R111</td>
+<td>Accessibility &ndash; Content</td>
+<td>S</td>
+<td>Alternative document instances</td>
+</tr>
+<tr>
+<td>R112</td>
+<td>Accessibility &ndash; Authoring System</td>
+<td>S</td>
+<td/>
+</tr>
+<tr>
+<td>R200</td>
+<td>Authorability</td>
+<td>S</td>
+<td/>
+</tr>
+<tr>
+<td>R201</td>
+<td>Multiple Natural Languages</td>
+<td>S</td>
+<td>Alternative document instances</td>
+</tr>
+<tr>
+<td>R202</td>
+<td>Natural Language Coverage</td>
+<td>S</td>
+<td>Unicode 4.0</td>
+</tr>
+<tr>
+<td>R203</td>
+<td>Natural Language Association Granularity</td>
+<td>S</td>
+<td>See <code>xml:lang</code></td>
+</tr>
+<tr>
+<td>R204</td>
+<td>Minimum Character Representability</td>
+<td>S</td>
+<td>Unicode 4.0</td>
+</tr>
+<tr>
+<td>R205</td>
+<td>Intrinsic and Extrinsic Text Content</td>
+<td>P</td>
+<td>Intrinsic only</td>
+</tr>
+<tr>
+<td>R206</td>
+<td>Markup Association</td>
+<td>P</td>
+<td>Intrinsic only</td>
+</tr>
+<tr>
+<td>R207</td>
+<td>Conditional Content</td>
+<td>N</td>
+<td/>
+</tr>
+<tr>
+<td>R208</td>
+<td>Flowed Text</td>
+<td>S</td>
+<td/>
+</tr>
+<tr>
+<td>R209</td>
+<td>Logical Flowed Text Vocabulary</td>
+<td>S</td>
+<td/>
+</tr>
+<tr>
+<td>R210</td>
+<td>Presentational Flowed Text Vocabulary</td>
+<td>S</td>
+<td>Implied mapping from logical flowed text.</td>
+</tr>
+<tr>
+<td>R211</td>
+<td>Flowed Text Vocabulary Relationship</td>
+<td>S</td>
+<td/>
+</tr>
+<tr>
+<td>R212</td>
+<td>Flowed Text Vocabulary Separation</td>
+<td>N</td>
+<td/>
+</tr>
+<tr>
+<td>R213</td>
+<td>Non-Flowed Text</td>
+<td>N</td>
+<td/>
+</tr>
+<tr>
+<td>R214</td>
+<td>Non-Flowed Text Vocabulary</td>
+<td>N</td>
+<td/>
+</tr>
+<tr>
+<td>R215</td>
+<td>Hybrid Flowed and Non-Flowed Text</td>
+<td>N</td>
+<td/>
+</tr>
+<tr>
+<td>R216</td>
+<td>Hyperlinking</td>
+<td>N</td>
+<td>Can support via XLink</td>
+</tr>
+<tr>
+<td>R217</td>
+<td>Embedded Graphics</td>
+<td>N</td>
+<td/>
+</tr>
+<tr>
+<td>R218</td>
+<td>Non-Embedded Graphics</td>
+<td>N</td>
+<td/>
+</tr>
+<tr>
+<td>R219</td>
+<td>Embedded Fonts</td>
+<td>N</td>
+<td/>
+</tr>
+<tr>
+<td>R220</td>
+<td>Non-Embedded Fonts</td>
+<td>N</td>
+<td/>
+</tr>
+<tr>
+<td>R221</td>
+<td>Descriptive Vocabulary</td>
+<td>S</td>
+<td>See <code>ttm:agent</code>, <code>ttm:role</code></td>
+</tr>
+<tr>
+<td>R222</td>
+<td>Embedded Audio</td>
+<td>N</td>
+<td/>
+</tr>
+<tr>
+<td>R223</td>
+<td>Non-Embedded Audio</td>
+<td>N</td>
+<td/>
+</tr>
+<tr>
+<td>R290</td>
+<td>Markup Format</td>
+<td>S</td>
+<td/>
+</tr>
+<tr>
+<td>R291</td>
+<td>Markup Format and Unicode Interaction</td>
+<td>S</td>
+<td/>
+</tr>
+<tr>
+<td>R292</td>
+<td>Extrinsic Resource References</td>
+<td>N</td>
+<td>No extrinsic references</td>
+</tr>
+<tr>
+<td>R293</td>
+<td>Schema Validity Specification</td>
+<td>S</td>
+<td/>
+</tr>
+<tr>
+<td>R300</td>
+<td>Inline Styling</td>
+<td>S</td>
+<td/>
+</tr>
+<tr>
+<td>R301</td>
+<td>Inline Styling Form</td>
+<td>P</td>
+<td>Inline and referential styling</td>
+</tr>
+<tr>
+<td>R301</td>
+<td>Out-of-Line Styling</td>
+<td>N</td>
+<td/>
+</tr>
+<tr>
+<td>R301</td>
+<td>Out-of-Line Styling Form</td>
+<td>N</td>
+<td/>
+</tr>
+<tr>
+<td>R304</td>
+<td>Styling Prioritization</td>
+<td>S</td>
+<td/>
+</tr>
+<tr>
+<td>R305</td>
+<td>Style Parameters &ndash; Aural</td>
+<td>N</td>
+<td/>
+</tr>
+<tr>
+<td>R306</td>
+<td>Style Parameters &ndash; Visual</td>
+<td>P</td>
+<td>Supports absolute position, background color, color, display none, display alignment,
+font family, font size, font style, font weight, height, line height, origin,
+opacity, overflow, padding (before, after, start, end), text alignment,
+text shadow (as outline), visibility, width, writing mode, z-index</td>
+</tr>
+<tr>
+<td>R390</td>
+<td>Style Parameter Symmetry</td>
+<td>S</td>
+<td/>
+</tr>
+<tr>
+<td>R391</td>
+<td>Style Parameter Definitions</td>
+<td>S</td>
+<td/>
+</tr>
+<tr>
+<td>R392</td>
+<td>Style Parameter Shorthands</td>
+<td>S</td>
+<td/>
+</tr>
+<tr>
+<td>R401</td>
+<td>Inline Timing</td>
+<td>S</td>
+<td/>
+</tr>
+<tr>
+<td>R402</td>
+<td>Out-of-Line Timing</td>
+<td>N</td>
+<td/>
+</tr>
+<tr>
+<td>R403</td>
+<td>Synchronization Parameters</td>
+<td>P</td>
+<td>Supports begin, end, dur</td>
+</tr>
+<tr>
+<td>R404</td>
+<td>Synchronization Parameter Value Spaces</td>
+<td>P</td>
+<td>Supports offset values, media marker values (SMPTE 12M), wall-clock values</td>
+</tr>
+<tr>
+<td>R405</td>
+<td>Time Containment Semantics</td>
+<td>P</td>
+<td>Supports sequential, parallel</td>
+</tr>
+<tr>
+<td>R500</td>
+<td>Animation Modes</td>
+<td>P</td>
+<td>Supports discrete</td>
+</tr>
+<tr>
+<td>R502</td>
+<td>Highlight Animation</td>
+<td>S</td>
+<td><code>&lt;set tts:backgroundColor="..."/&gt;</code></td>
+</tr>
+<tr>
+<td>R503</td>
+<td>Fade Transition Animation</td>
+<td>S</td>
+<td><code>&lt;set tts:opacity="..."/&gt;</code></td>
+</tr>
+<tr>
+<td>R504</td>
+<td>Animated Style Parameters &ndash; Aural</td>
+<td>N</td>
+<td/>
+</tr>
+<tr>
+ <td>R505</td>
+<td>Animated Style Parameters &ndash; Visual</td>
+<td>P</td>
+<td>Supports animating background color, color, display, opacity, origin, visibility</td>
+</tr>
+<tr>
+<td>N506</td>
+<td>Animated Content</td>
+<td>S</td>
+<td/>
+</tr>
+<tr>
+<td>R600</td>
+<td>Metadata Item Association</td>
+<td>S</td>
+<td>See <code>metadata</code>, <code>Metadata.class</code></td>
+</tr>
+<tr>
+<td>R601</td>
+<td>Metadata Item Constituents</td>
+<td>P</td>
+<td>Supports name, value</td>
+</tr>
+<tr>
+<td>R602</td>
+<td>Metadata Item Value Representation</td>
+<td>P</td>
+<td>See <code>metadata</code></td>
+</tr>
+<tr>
+<td>R603</td>
+<td>Metadata Item Extensibility</td>
+<td>S</td>
+<td>See <code>metadata</code></td>
+</tr>
+<tr>
+<td>R604</td>
+<td>Metadata Item Validation</td>
+<td>S</td>
+<td>See <code>metadata</code></td>
+</tr>
+<tr>
+<td>R690</td>
+<td>Dublin Core Preference</td>
+<td>N</td>
+<td>Uses <code>ttm:copyright</code>, <code>ttm:desc</code>, <code>ttm:title</code></td>
+</tr>
+</tbody>
+</table>
+</inform-div1>
+<inform-div1 id="derivation">
+<head>Vocabulary Derivation</head>
+<p>This appendix provides information about the derivation of TTML
+vocabulary, separately describing derivation of elements and
+attributes.</p>
+<div2>
+<head>Element Derivation</head>
+<p>The first column of <specref ref="element-vocab-derivation-table"/>
+specifies a TTML element vocabulary item; the second column specifies the
+syntactic and/or semantic model on which the vocabulary item is based;
+the third column specifies the reference that defines
+the model (if a model is indicated);
+the fourth column specifies details about the derivation; the last
+column refers to additional notes describing the nature of the
+derivation.</p>
+<p>In the fourth column, which describes details of derivation, a
+notation is use to indicate the addition or removal of an attribute.
+For example, in the derivation of the <el>tt:div</el> element, the
+details column includes "-@class", which denotes that the
+<att>class</att> attribute that is specified for use with the
+<el>xhtml:div</el> model element is not specified for use with the
+corresponding TTML element; in contrast, the details column includes
+"+@begin", which denotes that a <att>begin</att> attribute is added
+that is not specified for use with the <el>xhtml:div</el> model
+element.</p>
+<table id="element-vocab-derivation-table" role="common">
+<caption>Table J-1 &ndash; Elements</caption>
+<col width="20%"/>
+<col width="17%"/>
+<col width="13%" align="center"/>
+<col width="40%"/>
+<col width="10%" align="center"/>
+<tbody>
+<tr>
+<td><phrase role="strong">Element</phrase></td>
+<td><phrase role="strong">Model</phrase></td>
+<td><phrase role="strong">Reference</phrase></td>
+<td><phrase role="strong">Details</phrase></td>
+<td><phrase role="strong">Notes</phrase></td>
+</tr>
+<tr>
+<td><loc href="#document-structure-vocabulary-body"><code>tt:body</code></loc></td>
+<td><code>xhtml:body</code></td>
+<td><bibref ref="xhtml10"/></td>
+<td>-@class, -@dir, -@lang, -@on*, -@title; +@begin, +@dur, +@end, +@region,
++@timeContainer, +@ttm:*, +@tts:*; content model
+subsetted to zero or more division (div) children, and supersetted by
+optional metadata and animation children</td>
+<td>1,2</td>
+</tr>
+<tr>
+<td><loc href="#content-vocabulary-br"><code>tt:br</code></loc></td>
+<td><code>xhtml:br</code></td>
+<td><bibref ref="xhtml10"/></td>
+<td>-@class, -@title; +@ttm:*, +@tts:*, +@xml:lang, +@xml:space;
+content model supersetted by
+optional metadata and animation children for congruity with other
+content vocabulary</td>
+<td>1,2</td>
+</tr>
+<tr>
+<td><loc href="#content-vocabulary-div"><code>tt:div</code></loc></td>
+<td><code>xhtml:div</code></td>
+<td><bibref ref="xhtml10"/></td>
+<td>-@class, -@dir, -@lang, -@on*, -@title; +@begin, +@dur, +@end, +@region,
++@timeContainer, +@ttm:*, +@tts:*, +@xml:space; content model
+subsetted to zero or more paragraph (p) children, and supersetted by
+optional metadata and animation children</td>
+<td>1,2,3</td>
+</tr>
+<tr>
+<td><loc href="#document-structure-vocabulary-head"><code>tt:head</code></loc></td>
+<td><code>xhtml:head</code></td>
+<td><bibref ref="xhtml10"/></td>
+<td>-@dir, -@lang, -@profile; +@id, +@xml:space; content model changed to
+optional metadata children, followed by optional styling child,
+followed by optional layout child</td>
+<td>1,3</td>
+</tr>
+<tr>
+<td><loc href="#layout-vocabulary-layout"><code>tt:layout</code></loc></td>
+<td><code>fo:simple-page-master</code></td>
+<td><bibref ref="xsl11"/></td>
+<td>conceptual derivation</td>
+<td>4</td>
+</tr>
+<tr>
+<td><loc href="#metadata-vocabulary-metadata"><code>tt:metadata</code></loc></td>
+<td><code>svg:metadata</code></td>
+<td><bibref ref="svg11"/></td>
+<td>-@xml:base; +@ttm:*, +@xml:lang, +@xml:space; content model
+subsetted to foreign namespace element content only (no #PCDATA)</td>
+<td>3,5</td>
+</tr>
+<tr>
+<td><loc href="#content-vocabulary-p"><code>tt:p</code></loc></td>
+<td><code>xhtml:p</code></td>
+<td><bibref ref="xhtml10"/></td>
+<td>-@class, -@dir, -@lang, -@on*, -@title; +@begin, +@dur, +@end, +@region,
++@timeContainer, +@ttm:*, +@tts:*, +@xml:space; content model
+subsetted to zero or more span children, and supersetted by optional
+metadata and animation children</td>
+<td>1,2,3</td>
+</tr>
+<tr>
+<td><loc href="#layout-vocabulary-region"><code>tt:region</code></loc></td>
+<td><code>fo:region-*</code></td>
+<td><bibref ref="xsl11"/></td>
+<td>conceptual derivation</td>
+<td>4</td>
+</tr>
+<tr>
+<td><loc href="#animation-vocabulary-set"><code>tt:set</code></loc></td>
+<td><code>svg:set</code></td>
+<td><bibref ref="svg11"/></td>
+<td>-@* except begin, dur, end; +@tts:*, +@xml:lang, +@xml:space</td>
+<td>3,6</td>
+</tr>
+<tr>
+<td><loc href="#content-vocabulary-span"><code>tt:span</code></loc></td>
+<td><code>xhtml:span</code></td>
+<td><bibref ref="xhtml10"/></td>
+<td>-@class, -@dir, -@lang, -@on*, -@title; +@begin, +@dur, +@end, +@region,
++@timeContainer, +@ttm:*, +@tts:*, +@xml:space; content model
+subsetted to zero or more #PCDATA or break (br) children, and
+supersetted by optional metadata and animation children</td>
+<td>1,2,3</td>
+</tr>
+<tr>
+<td><loc href="#styling-vocabulary-style"><code>tt:style</code></loc></td>
+<td><emph>style specification</emph></td>
+<td><bibref ref="css2"/></td>
+<td>XML representation of identified set of pairs of style property
+name and value, with optional inclusion of other styles by reference
+to other style elements</td>
+<td>7</td>
+</tr>
+<tr>
+<td><loc href="#styling-vocabulary-styling"><code>tt:styling</code></loc></td>
+<td><code>xhtml:style</code></td>
+<td><bibref ref="xhtml10"/></td>
+<td>XML representation of a set of style specifications sets, each
+represented by a style child element</td>
+<td>1,7</td>
+</tr>
+<tr>
+<td><loc href="#document-structure-vocabulary-tt"><code>tt:tt</code></loc></td>
+<td><code>xhtml:html</code></td>
+<td><bibref ref="xhtml10"/></td>
+<td>-@dir, -@lang; +@id, +@ttp:*, +@xml:space; content model subsetted by
+permitting body and/or head to be optional</td>
+<td>1,8</td>
+</tr>
+<tr>
+<td><loc href="#metadata-vocabulary-actor"><code>ttm:actor</code></loc></td>
+<td><code>mpeg7:Creator</code></td>
+<td><bibref ref="mpeg7-5"/></td>
+<td>conceptual derivation</td>
+<td>4</td>
+</tr>
+<tr>
+<td><loc href="#metadata-vocabulary-agent"><code>ttm:agent</code></loc></td>
+<td><code>mpeg7:Agent</code></td>
+<td><bibref ref="mpeg7-5"/></td>
+<td>conceptual derivation</td>
+<td>4</td>
+</tr>
+<tr>
+<td><loc href="#metadata-vocabulary-copyright"><code>ttm:copyright</code></loc></td>
+<td><code>mpeg7:CopyrightString</code></td>
+<td><bibref ref="mpeg7-5"/></td>
+<td>conceptual derivation</td>
+<td>4</td>
+</tr>
+<tr>
+<td><loc href="#metadata-vocabulary-desc"><code>ttm:desc</code></loc></td>
+<td><code>svg:desc</code></td>
+<td><bibref ref="svg11"/></td>
+<td>-@class, -@style, -@xml:base</td>
+<td>2,5,9</td>
+</tr>
+<tr>
+<td><loc href="#metadata-vocabulary-name"><code>ttm:name</code></loc></td>
+<td><code>mpeg7:Name</code></td>
+<td><bibref ref="mpeg7-5"/></td>
+<td>conceptual derivation</td>
+<td>4</td>
+</tr>
+<tr>
+<td><loc href="#metadata-vocabulary-title"><code>ttm:title</code></loc></td>
+<td><code>svg:title</code></td>
+<td><bibref ref="svg11"/></td>
+<td>-@class, -@style, -@xml:base</td>
+<td>2,5,9</td>
+</tr>
+
+<tr>
+<td><loc href="#parameter-vocabulary-extension"><code>ttp:extension</code></loc></td>
+<td><code>@requiredExtensions</code></td>
+<td><bibref ref="svg11"/></td>
+<td>conceptual derivation</td>
+<td>10</td>
+</tr>
+<tr>
+<td><loc href="#parameter-vocabulary-extensions"><code>ttp:extensions</code></loc></td>
+<td><code>@requiredExtensions</code></td>
+<td><bibref ref="svg11"/></td>
+<td>conceptual derivation</td>
+<td>10</td>
+</tr>
+<tr>
+<td><loc href="#parameter-vocabulary-feature"><code>ttp:feature</code></loc></td>
+<td><code>@requiredFeatures</code></td>
+<td><bibref ref="svg11"/></td>
+<td>conceptual derivation</td>
+<td>10</td>
+</tr>
+<tr>
+<td><loc href="#parameter-vocabulary-features"><code>ttp:features</code></loc></td>
+<td><code>@requiredFeatures</code></td>
+<td><bibref ref="svg11"/></td>
+<td>conceptual derivation</td>
+<td>10</td>
+</tr>
+<tr>
+<td><loc href="#parameter-vocabulary-profile"><code>ttp:profile</code></loc></td>
+<td><code>@baseProfile</code></td>
+<td><bibref ref="svg11"/></td>
+<td>conceptual derivation</td>
+<td>11</td>
+</tr>
+</tbody>
+</table>
+<note>
+<olist>
+<item>
+<p>Derivation is indicated with respect to the strict DTD defined
+by <bibref ref="xhtml10"/>, &sect;A.1.</p>
+</item>
+<item>
+<p>The <att>class</att> attribute is effectively replaced by the
+<att>style</att>
+attribute, which, instead of specifying an inline style,
+refers indirectly to one or more <loc
+href="#styling-vocabulary-style"><el>style</el></loc>
+elements that define a set of style specification sets.</p>
+</item>
+<item>
+<p>The <att>xml:lang</att> and <att>xml:space</att> attributes are defined for all element
+types in order to support their inheritance semantics to operate in
+the context of foreign namespace elements.</p>
+</item>
+<item>
+<p>Derivation is conceptual (notional) only.</p>
+</item>
+<item>
+<p>The <att>xml:base</att> attribute is not used since there are no external
+references from core vocabulary.</p>
+</item>
+<item>
+<p>The <att>attributeName</att> and <att>to</att> attributes of
+<el>svg:set</el> are replaced by the
+direct expression of the target attribute name and value by use of a
+<att>tts:*</att> attribute.</p>
+</item>
+<item>
+<p>CSS style specification syntax is mapped to XML by use of
+attributes defined in the TT Style Namespace.</p>
+</item>
+<item>
+<p>The <att>xml:id</att> attribute is defined for use on all element types.</p>
+</item>
+<item>
+<p>The <att>style</att> attribute is supported only on content
+elements.</p>
+</item>
+<item>
+<p>Derived from the use of <code>@requiredExtensions</code>
+and <code>@requiredFeatures</code> on the <code>svg:svg</code> element,
+but extended to support distinct specification of optionality.</p>
+</item>
+<item>
+<p>Derived from the use of <code>@baseProfile</code>
+and <code>@version</code> on the <code>svg:svg</code> element.</p>
+</item>
+</olist>
+</note>
+</div2>
+<div2>
+<head>Attribute Derivation</head>
+<p>The first column of <specref ref="attribute-vocab-derivation-table"/>
+specifies a TTML attribute vocabulary item; the second column specifies the
+syntactic and/or semantic model on which the vocabulary item is based;
+the third column specifies the reference that defines
+the model (if a model is indicated);
+the fourth column specifies details about the derivation; the last
+column refers to additional notes describing the nature of the
+derivation.</p>
+<p>In the fourth column, which describes details of derivation, a
+notation is use to indicate the addition or removal of an attribute
+value.  For example, in the derivation of the <att>timeContainer</att>
+attribute,
+the details column includes "-excl", which denotes that the
+<code>excl</code> value that is specified for use with the
+<att>timeContainer</att> model attribute is not specified for use with the
+corresponding TTML attribute; similarly, an "+<emph>value</emph>"
+in the details column indicates that the attribute's values have been
+extended to include <emph>value</emph>.</p>
+<p>Only those attributes that are specified for use on more than one TTML
+element type are listed below. Those per-element namespace attributes
+that are uniquely defined for a specific TTML element type are not
+listed below, but are considered to be part of the specific element
+type's derivation described in <specref
+ref="element-vocab-derivation-table"/>
+above.</p>
+<table id="attribute-vocab-derivation-table" role="common">
+<caption>Table J-2 &ndash; Attributes</caption>
+<col width="20%"/>
+<col width="17%"/>
+<col width="13%" align="center"/>
+<col width="40%"/>
+<col width="10%" align="center"/>
+<tbody>
+<tr>
+<td><phrase role="strong">Attribute</phrase></td>
+<td><phrase role="strong">Model</phrase></td>
+<td><phrase role="strong">Reference</phrase></td>
+<td><phrase role="strong">Details</phrase></td>
+<td><phrase role="strong">Notes</phrase></td>
+</tr>
+<tr>
+<td><loc href="#timing-attribute-begin"><code>begin</code></loc></td>
+<td><code>begin</code></td>
+<td><bibref ref="smil21"/></td>
+<td>see notes</td>
+<td>2,3,4</td>
+</tr>
+<tr>
+<td><loc href="#timing-attribute-dur"><code>dur</code></loc></td>
+<td><code>dur</code></td>
+<td><bibref ref="smil21"/></td>
+<td>see notes</td>
+<td>2,3,4</td>
+</tr>
+<tr>
+<td><loc href="#timing-attribute-end"><code>end</code></loc></td>
+<td><code>end</code></td>
+<td><bibref ref="smil21"/></td>
+<td>see notes</td>
+<td>2,3,4</td>
+</tr>
+<tr>
+<td><loc href="#layout-attribute-region"><code>region</code></loc></td>
+<td><code>master-reference</code></td>
+<td><bibref ref="xsl11"/></td>
+<td>conceptual derivation</td>
+<td></td>
+</tr>
+<tr>
+<td><loc href="#style-attribute-style"><code>style</code></loc></td>
+<td><code>class</code></td>
+<td><bibref ref="css2"/></td>
+<td>dereferences style specification(s) directly</td>
+<td></td>
+</tr>
+<tr>
+<td><loc href="#timing-attribute-timeContainer"><code>timeContainer</code></loc></td>
+<td><code>timeContainer</code></td>
+<td><bibref ref="smil21"/></td>
+<td>-excl, -none; no default attribute value</td>
+<td>5</td>
+</tr>
+<tr>
+<td><loc href="#metadata-attribute-agent"><code>ttm:agent</code></loc></td>
+<td><emph>none</emph></td>
+<td></td>
+<td>used to attribute agent of content</td>
+<td></td>
+</tr>
+<tr>
+<td><loc href="#metadata-attribute-role"><code>ttm:role</code></loc></td>
+<td><emph>none</emph></td>
+<td></td>
+<td>used to attribute role of content</td>
+<td></td>
+</tr>
+<tr>
+<td><loc href="#parameter-attribute-cellResolution"><code>ttp:cellResolution</code></loc></td>
+<td><emph>none</emph></td>
+<td></td>
+<td>expresses uniform grid resolution for cell based coordinates</td>
+<td></td>
+</tr>
+<tr>
+<td><loc href="#parameter-attribute-clockMode"><code>ttp:clockMode</code></loc></td>
+<td><emph>none</emph></td>
+<td></td>
+<td>determines how to interpret time expressions</td>
+<td></td>
+</tr>
+<tr>
+<td><loc href="#parameter-attribute-frameRate"><code>ttp:frameRate</code></loc></td>
+<td><emph>none</emph></td>
+<td></td>
+<td>expresses integral frame rate</td>
+<td></td>
+</tr>
+<tr>
+<td><loc href="#parameter-attribute-frameRateMultiplier"><code>ttp:frameRateMultiplier</code></loc></td>
+<td><emph>none</emph></td>
+<td></td>
+<td>used to express non-integral, rational frame rates</td>
+<td></td>
+</tr>
+<tr>
+<td><loc href="#parameter-attribute-markerMode"><code>ttp:markerMode</code></loc></td>
+<td><emph>none</emph></td>
+<td></td>
+<td>expresses marker continuity semantics</td>
+<td></td>
+</tr>
+<tr>
+<td><loc href="#parameter-attribute-pixelAspectRatio"><code>ttp:pixelAspectRatio</code></loc></td>
+<td><emph>none</emph></td>
+<td></td>
+<td>expresses pixel aspect ratio of related media</td>
+<td></td>
+</tr>
+<tr>
+<td><loc href="#parameter-attribute-profile"><code>ttp:profile</code></loc></td>
+<td><emph>none</emph></td>
+<td></td>
+<td>expresses profile of TTML used by a <emph>Document Instance</emph></td>
+<td></td>
+</tr>
+<tr>
+<td><loc href="#parameter-attribute-dropMode"><code>ttp:dropMode</code></loc></td>
+<td><emph>none</emph></td>
+<td></td>
+<td>expresses frame counting (drop) modes</td>
+<td></td>
+</tr>
+<tr>
+<td><loc href="#parameter-attribute-subFrameRate"><code>ttp:subFrameRate</code></loc></td>
+<td><emph>none</emph></td>
+<td></td>
+<td>expresses sub-frame rate</td>
+<td></td>
+</tr>
+<tr>
+<td><loc href="#parameter-attribute-tickRate"><code>ttp:tickRate</code></loc></td>
+<td><emph>none</emph></td>
+<td></td>
+<td>used to interpret tick based time expressions</td>
+<td></td>
+</tr>
+<tr>
+<td><loc href="#parameter-attribute-timeBase"><code>ttp:timeBase</code></loc></td>
+<td><emph>none</emph></td>
+<td></td>
+<td>used to interpret semantics of time expressions</td>
+<td></td>
+</tr>
+<tr>
+<td><loc href="#style-attribute-backgroundColor"><code>tts:backgroundColor</code></loc></td>
+<td><code>background-color</code></td>
+<td><bibref ref="xsl11"/></td>
+<td><code>-inherit</code></td>
+<td>1,6</td>
+</tr>
+<tr>
+<td><loc href="#style-attribute-color"><code>tts:color</code></loc></td>
+<td><code>color</code></td>
+<td><bibref ref="xsl11"/></td>
+<td><code>-inherit</code></td>
+<td>6</td>
+</tr>
+<tr>
+<td><loc href="#style-attribute-direction"><code>tts:direction</code></loc></td>
+<td><code>direction</code></td>
+<td><bibref ref="xsl11"/></td>
+<td><code>-inherit</code></td>
+<td></td>
+</tr>
+<tr>
+<td><loc href="#style-attribute-display"><code>tts:display</code></loc></td>
+<td><code>display</code></td>
+<td><bibref ref="css2"/></td>
+<td>only <code>auto</code>, <code>none</code></td>
+<td></td>
+</tr>
+<tr>
+<td><loc href="#style-attribute-displayAlign"><code>tts:displayAlign</code></loc></td>
+<td><code>display-align</code></td>
+<td><bibref ref="xsl11"/></td>
+<td><code>-inherit</code></td>
+<td>1</td>
+</tr>
+<tr>
+<td><loc href="#style-attribute-extent"><code>tts:extent</code></loc></td>
+<td><code>width</code>, <code>height</code></td>
+<td><bibref ref="xsl11"/></td>
+<td>shorthand property</td>
+<td></td>
+</tr>
+<tr>
+<td><loc href="#style-attribute-fontFamily"><code>tts:fontFamily</code></loc></td>
+<td><code>font-family</code></td>
+<td><bibref ref="xsl11"/></td>
+<td><code>-inherit</code>, extends generic family names</td>
+<td>1</td>
+</tr>
+<tr>
+<td><loc href="#style-attribute-fontSize"><code>tts:fontSize</code></loc></td>
+<td><code>font-size</code></td>
+<td><bibref ref="xsl11"/></td>
+<td><code>-inherit</code></td>
+<td>1,7</td>
+</tr>
+<tr>
+<td><loc href="#style-attribute-fontStyle"><code>tts:fontStyle</code></loc></td>
+<td><code>font-style</code></td>
+<td><bibref ref="xsl11"/></td>
+<td><code>-inherit</code>, <code>-backslant</code></td>
+<td>1</td>
+</tr>
+<tr>
+<td><loc href="#style-attribute-fontWeight"><code>tts:fontWeight</code></loc></td>
+<td><code>font-weight</code></td>
+<td><bibref ref="xsl11"/></td>
+<td><code>-inherit</code>, <code>-bolder</code>, <code>-lighter</code>, <code>-&lt;number&gt;</code></td>
+<td>1</td>
+</tr>
+<tr>
+<td><loc href="#style-attribute-lineHeight"><code>tts:lineHeight</code></loc></td>
+<td><code>line-height</code></td>
+<td><bibref ref="xsl11"/></td>
+<td><code>-inherit</code>, <code>-&lt;number&gt;</code>, <code>-&lt;space&gt;</code></td>
+<td>1</td>
+</tr>
+<tr>
+<td><loc href="#style-attribute-opacity"><code>tts:opacity</code></loc></td>
+<td><code>opacity</code></td>
+<td><bibref ref="css3-color"/></td>
+<td><code>-inherit</code></td>
+<td></td>
+</tr>
+<tr>
+<td><loc href="#style-attribute-origin"><code>tts:origin</code></loc></td>
+<td><code>top</code>, <code>left</code></td>
+<td><bibref ref="xsl11"/></td>
+<td>shorthand property</td>
+<td></td>
+</tr>
+<tr>
+<td><loc href="#style-attribute-overflow"><code>tts:overflow</code></loc></td>
+<td><code>overflow</code></td>
+<td><bibref ref="xsl11"/></td>
+<td><code>-inherit</code>, <code>-auto</code>, <code>-error-if-overflow</code></td>
+<td>8</td>
+</tr>
+<tr>
+<td><loc href="#style-attribute-padding"><code>tts:padding</code></loc></td>
+<td><code>padding</code></td>
+<td><bibref ref="xsl11"/></td>
+<td><code>-inherit</code></td>
+<td>9</td>
+</tr>
+<tr>
+<td><loc href="#style-attribute-showBackground"><code>tts:showBackground</code></loc></td>
+<td><code>showBackground</code></td>
+<td><bibref ref="smil21"/></td>
+<td><code>-inherit</code></td>
+<td></td>
+</tr>
+<tr>
+<td><loc href="#style-attribute-textAlign"><code>tts:textAlign</code></loc></td>
+<td><code>text-align</code></td>
+<td><bibref ref="xsl11"/></td>
+<td><code>-inherit</code></td>
+<td>1</td>
+</tr>
+<tr>
+<td><loc href="#style-attribute-textDecoration"><code>tts:textDecoration</code></loc></td>
+<td><code>text-decoration</code></td>
+<td><bibref ref="xsl11"/></td>
+<td><code>-inherit</code></td>
+<td>1,10,13</td>
+</tr>
+<tr>
+<td><loc href="#style-attribute-textOutline"><code>tts:textOutline</code></loc></td>
+<td><code>text-shadow</code></td>
+<td><bibref ref="xsl11"/></td>
+<td><code>-inherit</code></td>
+<td>11,13</td>
+</tr>
+<tr>
+<td><loc href="#style-attribute-unicodeBidi"><code>tts:unicodeBidi</code></loc></td>
+<td><code>unicode-bidi</code></td>
+<td><bibref ref="xsl11"/></td>
+<td><code>-inherit</code></td>
+<td>1</td>
+</tr>
+<tr>
+<td><loc href="#style-attribute-visibility"><code>tts:visibility</code></loc></td>
+<td><code>visibility</code></td>
+<td><bibref ref="xsl11"/></td>
+<td><code>-inherit</code>, <code>-collapse</code></td>
+<td></td>
+</tr>
+<tr>
+<td><loc href="#style-attribute-wrapOption"><code>tts:wrapOption</code></loc></td>
+<td><code>wrap-option</code></td>
+<td><bibref ref="xsl11"/></td>
+<td><code>-inherit</code></td>
+<td>1</td>
+</tr>
+<tr>
+<td><loc href="#style-attribute-writingMode"><code>tts:writingMode</code></loc></td>
+<td><code>writing-mode</code></td>
+<td><bibref ref="xsl11"/></td>
+<td><code>-inherit</code>, <code>+tblr</code></td>
+<td>1</td>
+</tr>
+<tr>
+<td><loc href="#style-attribute-zIndex"><code>tts:zIndex</code></loc></td>
+<td><code>z-index</code></td>
+<td><bibref ref="xsl11"/></td>
+<td><code>-inherit</code></td>
+<td>1</td>
+</tr>
+<tr>
+<td><loc href="#content-attribute-id"><code>xml:id</code></loc></td>
+<td><code>xml:id</code></td>
+<td><bibref ref="xmlid"/></td>
+<td>complies with model</td>
+<td></td>
+</tr>
+<tr>
+<td><loc href="#content-attribute-lang"><code>xml:lang</code></loc></td>
+<td><code>xml:lang</code></td>
+<td><bibref ref="xml10"/></td>
+<td>complies with model</td>
+<td></td>
+</tr>
+<tr>
+<td><loc href="#content-attribute-space"><code>xml:space</code></loc></td>
+<td><code>xml:space</code></td>
+<td><bibref ref="xml10"/></td>
+<td>see notes</td>
+<td>12</td>
+</tr>
+</tbody>
+</table>
+<note>
+<olist>
+<item>
+<p>Attribute name and/or value(s) are normalized to use
+<emph>lowerCamelCase</emph> naming convention.</p>
+</item>
+<item>
+<p>Restricted to expressing a clock value that denotes one of the
+following in accordance to whether the parameter expressed by the
+<att>ttp:timeBase</att> attribute is <code>media</code>, <code>smpte</code>,
+or <code>clock</code>, respectively:
+(1) an offset from an implicit syncbase that is linked to a media time
+line, (2) an event time
+that represents the occurrence of an implicit media marker, or (3) a wall-clock
+time.</p>
+</item>
+<item>
+<p>Syntactically subsets and supersets the <bibref
+ref="smil21"/>&nbsp;<code>Clock-value</code> syntax as follows:
+(1) requires non-negative <code>Full-clock-value</code> or
+<code>Timecount-value</code>;
+(2) if <code>Full-clock-value</code>
+then <emph>hours</emph> must be two or more digits;
+(3) if <code>Timecount-value</code>, then <emph>metric</emph> must be
+specified;
+(4) uses <code>m</code> as alias for <code>min</code> metric to denote
+minutes;
+(5) adds <code>f</code> and <code>t</code> metrics denoting frames and
+ticks, respectively;
+(6) adds alternative expression of optional <code>Fraction</code> in
+<code>Full-clock-value</code> by specifying frame count or frame
+count with subframe count.
+</p>
+</item>
+<item>
+<p>
+Interpretation of time expression is further constrained by
+parameters expressed by
+<att>ttp:clockMode</att>,
+<att>ttp:dropMode</att>,
+<att>ttp:frameRate</att>,
+<att>ttp:frameRateMultiplier</att>,
+<att>ttp:markerMode</att>,
+<att>ttp:subFrameRate</att>,
+<att>ttp:tickRate</att>, and
+<att>ttp:timeBase</att> attributes.</p>
+</item>
+<item>
+<p>Uses subset of named colors from model to which two aliases are
+added as follows: <code>magenta</code> as <code>fuchsia</code>, and <code>cyan</code>
+as <code>aqua</code>.</p>
+</item>
+<item>
+<p>If not specified, then parallel (par) container semantics apply to
+the element types specified by <specref
+ref="timing-attribute-timeContainer"/>.</p>
+</item>
+<item>
+<p>Restricts size to length specification which can be a percentage;
+adds optional second length (or percentage) for
+specifying separate horizontal and vertical scaling of glyph's EM
+square.</p>
+</item>
+<item>
+<p>Expressed in terms of writing mode relative padding properties
+rather than absolute padding properties.</p>
+</item>
+<item>
+<p>Excludes <code>blink</code> and <code>no-blink</code> values.</p>
+</item>
+<item>
+<p>Uses only one length specification instead of two, where one length
+defines distance of outline effect from nominal edge of glyph contour
+outline perpendicular to point of glyph contour. Percentage lengths
+are also added to express outline effect in relative to font size.
+Outline effects are intended to be drawn both outside of outer closed
+contours and inside of inner closed contours.</p>
+</item>
+<item>
+<p>On root element, default attribute value specified as
+<code>default</code>, which is defined in terms of whitespace
+normalization. Semantics of preservation and default normalization are
+defined in terms of presentation semantics by <specref
+ref="content-attribute-space"/>.</p>
+</item>
+<item>
+<p>Defined to be inheritable.</p>
+</item>
+</olist>
+</note>
+</div2>
+</inform-div1>
+<inform-div1 id="qa">
+<head>QA Framework Compliance</head>
+<p>This appendix specifies the compliance of this specification with the
+requirements and guidelines defined by <xspecref
+href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/">QA
+Framework Specifications Guidelines</xspecref>&nbsp;<bibref
+ref="qaf-sg"/>.</p>
+<div2>
+<head>Requirements</head>
+<table id="qa-framework-requirements-table" role="common">
+<caption>Table K-1 &ndash; QA Framework Requirements Checklist</caption>
+<col width="76%"/>
+<col width="6%" align="center"/>
+<col width="6%" align="center"/>
+<col width="6%" align="center"/>
+<col width="6%" align="center"/>
+<tbody>
+<tr>
+<td><phrase role="strong">Requirement</phrase></td>
+<td><phrase role="strong">YES</phrase></td>
+<td><phrase role="strong">NO</phrase></td>
+<td><phrase role="strong">N/A</phrase></td>
+<td><phrase role="strong">Notes</phrase></td>
+</tr>
+<tr>
+<td><xspecref href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#include-conformance-clause-principle">Requirement 01: Include a conformance
+clause</xspecref></td>
+<td><loc href="#conformance">YES</loc></td>
+<td/>
+<td/>
+<td/>
+</tr>
+<tr>
+<td><xspecref href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#define-scope-principle">Requirement 02: Define the scope.</xspecref></td>
+<td><loc href="#intro">YES</loc></td>
+<td/>
+<td/>
+<td/>
+</tr>
+<tr>
+<td><xspecref href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#implement-principle">Requirement 03: Identify who or what will implement the specification.</xspecref></td>
+<td><loc href="#conformance">YES</loc></td>
+<td/>
+<td/>
+<td/>
+</tr>
+<tr>
+<td><xspecref href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#ref-norm-principle">Requirement 04: Make a list of normative references.</xspecref></td>
+<td><loc href="#references">YES</loc></td>
+<td/>
+<td/>
+<td/>
+</tr>
+<tr>
+<td><xspecref href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#define-terms-principle">Requirement 05: Define the terms used in the normative parts of the specification.</xspecref></td>
+<td><loc href="#definitions">YES</loc></td>
+<td/>
+<td/>
+<td/>
+</tr>
+<tr>
+<td><xspecref href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#conf-label-principle">Requirement 06: Create conformance labels for each part of the conformance model.</xspecref></td>
+<td><loc href="#conformance">YES</loc></td>
+<td/>
+<td/>
+<td/>
+</tr>
+<tr>
+<td><xspecref href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#consistent-style-principle">Requirement 07: Use a consistent style for conformance requirements and explain how to distinguish them.</xspecref></td>
+<td><loc href="#conventions">YES</loc></td>
+<td/>
+<td/>
+<td/>
+</tr>
+<tr>
+<td><xspecref href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#req-opt-conf-principle">Requirement 08: Indicate which conformance requirements are mandatory, which are recommended, and which are optional.</xspecref></td>
+<td><loc href="#conventions">YES</loc></td>
+<td/>
+<td/>
+<td/>
+</tr>
+<tr>
+<td><xspecref href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#subdivide-mandatory-principle">Requirement 09: If the technology is subdivided, then indicate which subdivisions are mandatory for conformance.</xspecref></td>
+<td><loc href="#conformance">YES</loc></td>
+<td/>
+<td/>
+<td/>
+</tr>
+<tr>
+<td><xspecref href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#subdiv-constraints-principle">Requirement 10: If the technology is subdivided, then address subdivision constraints.</xspecref></td>
+<td><loc href="#conformance">YES</loc></td>
+<td/>
+<td/>
+<td/>
+</tr>
+<tr>
+<td><xspecref href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#likehood-extension-principle">Requirement 11: Address Extensibility.</xspecref></td>
+<td><loc href="#doctypes">YES</loc></td>
+<td/>
+<td/>
+<td/>
+</tr>
+<tr>
+<td><xspecref href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#deprecated-feature-principle">Requirement 12: Identify deprecated features.</xspecref></td>
+<td/>
+<td/>
+<td>N/A</td>
+<td>1</td>
+</tr>
+<tr>
+<td><xspecref href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#degree-support-principle">Requirement 13: Define how each class of product handles each deprecated feature.</xspecref></td>
+<td/>
+<td/>
+<td>N/A</td>
+<td>1</td>
+</tr>
+</tbody>
+</table>
+<note>
+<olist>
+<item>
+<p>No feature is deprecated by this version of this specification.</p>
+</item>
+</olist>
+</note>
+</div2>
+<div2>
+<head>Guidelines</head>
+<table id="qa-framework-guidelines-table" role="common">
+<caption>Table K-2 &ndash; QA Framework Guidelines Checklist</caption>
+<col width="76%"/>
+<col width="6%" align="center"/>
+<col width="6%" align="center"/>
+<col width="6%" align="center"/>
+<col width="6%" align="center"/>
+<tbody>
+<tr>
+<td><phrase role="strong">Guideline</phrase></td>
+<td><phrase role="strong">YES</phrase></td>
+<td><phrase role="strong">NO</phrase></td>
+<td><phrase role="strong">N/A</phrase></td>
+<td><phrase role="strong">Notes</phrase></td>
+</tr>
+<tr>
+<td><xspecref href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#conformance-model-gp">Good Practice 01: Define the specification's conformance model in the conformance clause.</xspecref></td>
+<td><loc href="#conformance">YES</loc></td>
+<td/>
+<td/>
+<td/>
+</tr>
+<tr>
+<td><xspecref href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#norm-informative-gp">Good Practice 02: Specify in the conformance clause how to distinguish normative from informative content.</xspecref></td>
+<td><loc href="#conventions">YES</loc></td>
+<td/>
+<td/>
+<td/>
+</tr>
+<tr>
+<td><xspecref href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#conformance-claim-gp">Good Practice 03: Provide the wording for conformance claims.</xspecref></td>
+<td><loc href="#claims">YES</loc></td>
+<td/>
+<td/>
+<td/>
+</tr>
+<tr>
+<td><xspecref href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#ics-gp">Good Practice 04: Provide an Implementation Conformance Statement Pro Forma.</xspecref></td>
+<td/>
+<td>NO</td>
+<td/>
+<td/>
+</tr>
+<tr>
+<td><xspecref href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#ics-claim-gp">Good Practice 05: Require an Implementation Conformance Statement as part of valid conformance claims.</xspecref></td>
+<td><loc href="#claims">YES</loc></td>
+<td/>
+<td/>
+<td/>
+</tr>
+<tr>
+<td><xspecref href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#use-example-gp">Good Practice 06: Provide examples, use cases, and graphics.</xspecref></td>
+<td><loc href="#example">YES</loc></td>
+<td/>
+<td/>
+<td/>
+</tr>
+<tr>
+<td><xspecref href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#write-sample-gp">Good Practice 07: Write sample code or tests.</xspecref></td>
+<td>YES</td>
+<td/>
+<td/>
+<td/>
+</tr>
+<tr>
+<td><xspecref href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#ref-define-practice">Good Practice 08: When imposing requirements by normative references, address conformance dependencies.</xspecref></td>
+<td><loc href="#references">YES</loc></td>
+<td/>
+<td/>
+<td>1</td>
+</tr>
+<tr>
+<td><xspecref href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#define-terms-inline-gp">Good Practice 09: Define unfamiliar terms in-line and consolidate the definitions in a glossary section.</xspecref></td>
+<td><loc href="#definitions">YES</loc></td>
+<td/>
+<td/>
+<td/>
+</tr>
+<tr>
+<td><xspecref href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#reuse-terms-gp">Good Practice 10: Use terms already defined without changing their definition.</xspecref></td>
+<td><loc href="#definitions">YES</loc></td>
+<td/>
+<td/>
+<td>2</td>
+</tr>
+<tr>
+<td><xspecref href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#formal-language-gp">Good Practice 11: Use formal languages when possible.</xspecref></td>
+<td><loc href="#schemas">YES</loc></td>
+<td/>
+<td/>
+<td/>
+</tr>
+<tr>
+<td><xspecref href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#write-assertion-gp">Good Practice 12: Write Test Assertions.</xspecref></td>
+<td/>
+<td>NO</td>
+<td/>
+<td>3</td>
+</tr>
+<tr>
+<td><xspecref href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#subdivide-foster-gp">Good Practice 13: Create subdivisions of the technology when warranted.</xspecref></td>
+<td><loc href="#conformance">YES</loc></td>
+<td/>
+<td/>
+<td/>
+</tr>
+<tr>
+<td><xspecref href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#rules-profiles-gp">Good Practice 14: If the technology is profiled, define rules for creating new profiles.</xspecref></td>
+<td><loc href="#vocabulary-profiles">YES</loc></td>
+<td/>
+<td/>
+<td/>
+</tr>
+<tr>
+<td><xspecref href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#need-option-gp">Good Practice 15:Use optional features as warranted.</xspecref></td>
+<td>YES</td>
+<td/>
+<td/>
+<td/>
+</tr>
+<tr>
+<td><xspecref href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#label-options-gp">Good Practice 16: Clearly identify optional features.</xspecref></td>
+<td>YES</td>
+<td/>
+<td/>
+<td/>
+</tr>
+<tr>
+<td><xspecref href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#constraints-gp">Good Practice 17: Indicate any limitations or constraints on optional features.</xspecref></td>
+<td>YES</td>
+<td/>
+<td/>
+<td/>
+</tr>
+<tr>
+<td><xspecref href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#extensions-prohibited-gp">Good Practice 18: If extensibility is allowed, define an extension mechanism.</xspecref></td>
+<td><loc href="#extension-vocabulary-overview">YES</loc></td>
+<td/>
+<td/>
+<td/>
+</tr>
+<tr>
+<td><xspecref href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#breaking-conformance-gp">Good Practice 19: Warn extension creators to create extensions that do not interfere with conformance.</xspecref></td>
+<td><loc href="#extension-vocabulary-overview">YES</loc></td>
+<td/>
+<td/>
+<td/>
+</tr>
+<tr>
+<td><xspecref href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#define-error-gp">Good Practice 20: Define error-handling for unknown extensions.</xspecref></td>
+<td><loc href="#conformance-processor">YES</loc></td>
+<td/>
+<td/>
+<td>4</td>
+</tr>
+<tr>
+<td><xspecref href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#workaround-gp">Good Practice 21: Explain how to avoid using a deprecated feature.</xspecref></td>
+<td/>
+<td/>
+<td>N/A</td>
+<td>5</td>
+</tr>
+<tr>
+<td><xspecref href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#obsolete-gp">Good Practice 22: Identify obsolete features.</xspecref></td>
+<td/>
+<td/>
+<td>N/A</td>
+<td>5</td>
+</tr>
+<tr>
+<td><xspecref href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#error-handling-gp">Good Practice 23: Define an error handling mechanism.</xspecref></td>
+<td><loc href="#reduced-infoset">YES</loc></td>
+<td/>
+<td/>
+<td/>
+</tr>
+</tbody>
+</table>
+<note>
+<olist>
+<item>
+<p>When making normative references to external specifications,
+specific clauses or sections are cited.</p>
+</item>
+<item>
+<p>See also <specref ref="derivation"/>.</p>
+</item>
+<item>
+<p>Test assertions and test suites will be provided prior to entering
+Proposed Recommendation (PR) phase.</p>
+</item>
+<item>
+<p>See criterion #3 in <specref
+ref="conformance-processor"/> and definition of
+TTML <loc href="#doctypes">Abstract Document Instance</loc>.</p>
+</item>
+<item>
+<p>No feature is deprecated or obsoleted by this version of this specification.</p>
+</item>
+</olist>
+</note>
+</div2>
+</inform-div1>
+<inform-div1 id="streaming">
+<head>Streaming TTML Content</head>
+<p>TTML Content is designed to support streamability by implementing the
+following properties:</p>
+<ulist>
+<item>
+<p>can be progressively encoded (i.e., does not require computing
+subsequent data prior to sending current data);</p>
+</item>
+<item>
+<p>can be progressively decoded (i.e., does not require forward
+references, but uses only reverse references when necessary);</p>
+</item>
+<item>
+<p>does not require dereferencing (and subsequent loading) of any
+resources other than TTML Content (i.e., no embedded URIs);</p>
+</item>
+<item>
+<p>does not support alternative content forms (e.g., different
+language, graphics formats, time bases) in a single document;</p>
+</item>
+<item>
+<p>has timing structure compiled into inline format that makes
+possible a temporal ordering of content that follows temporal
+presentation order;</p>
+</item>
+<item>
+<p>constrains content models to prevent arbitrary nested content
+structures;</p>
+</item>
+</ulist>
+<p>One possible means by which TTML Content may be streamed is to
+partition a <emph>Document Instance</emph>'s information set into
+non-overlapping fragments, where one particular fragment, call it the
+<emph>root fragment</emph>, represents the front matter (head) of the
+<emph>Document Instance</emph> as well as its top level structural elements, and
+other fragments represent content whose time intervals are expected to
+be active in parallel.</p>
+<p>In applications that require arbitrary (random) entry into a
+stream, i.e., the property of being able to start reading data at an
+arbitrary data access unit, the root fragment will be repetitively
+transmitted (inserted) into the stream in order to permit a decoder to
+resynchronize and acquire sufficient structural information in the
+information set in order to interpret subsequent content
+fragments.</p>
+<p>An example of such a fragmentation of a <emph>Document Instance</emph> is
+shown in <specref ref="fragment-streaming-graphic"/>.</p>
+<table id="fragment-streaming-graphic" role="example-images">
+<caption>Figure 3 &ndash; Fragment Streaming</caption>
+<col/>
+<tbody>
+<tr>
+<td><graphic id="graphic-fragment-streaming" source="images/streaming.png" alt="Fragment Streaming"/></td>
+</tr>
+</tbody>
+</table>
+<note>
+<p>This specification does not define a transport buffer model or a decoder
+capabilities model.</p>
+</note>
+</inform-div1>
+<inform-div1 id="concrete-encoding">
+<head>Concrete Encoding</head>
+<p>In the absence of other requirements, it is recommended that a <emph>Document Instance</emph> be concretely encoded as a
+well-formed XML 1.0 <bibref ref="xml10"/> document using the UTF-8 character encoding.</p>
+</inform-div1>
+<inform-div1 id="time-expression-semantics">
+<head>Time Expression Semantics</head>
+<p>This appendix describes the intended semantics for interpreting time expressions in <emph>Document Instances</emph>.</p>
+<note role="elaboration">
+<p>It is expected that the information in this appendix will be elevated to normative status in a future revision of this specification.</p>
+</note>
+<note role="clarification">
+<p>The phrase <emph>local real time</emph> as used below is intended to model a virtual real time clock in the document processing context, where
+<emph>local</emph> means in the immediate proximity of the implementation of this processing context. The intent
+of defining relationships with this virtual clock is to establish a locally valid physical realization of time for didactic purposes.</p>
+</note>
+<note role="clarification">
+<p>The phrase <emph>play rate</emph> as used below is intended to model a (possibly variable) parameter in the document processing context wherein
+the rate of playback (or interpretation) of time may artificially dilated or narrowed, for example, when slowing down or speeding up the rate of
+playback of a <emph>Related Media Object</emph>. Without loss of generality, the following discussion assumes a fixed play(back) rate. In the case of
+variable play rates, appropriate adjustments may need to be made to the resulting computations.</p>
+</note>
+<div2 id="time-expression-semantics-clock">
+<head>Clock Time Base</head>
+<p>When operating with the <code>clock</code> time base, the following semantics should be applied for interpreting time expressions,
+as defined by <loc href="#timing-value-timeExpression">&lt;timeExpression&gt;</loc>, and their relationship to media time and local real time.</p>
+<p>The clock time base <phrase role="strong"><code>C</code></phrase> is related to local real time <phrase role="strong"><code>R</code></phrase>
+expressed in an arbitrary (implementation defined) epoch <phrase role="strong"><code>E</code></phrase>
+as follows:</p>
+<table id="clock-time-and-real-time" role="semantics">
+<caption>TTML Semantics &ndash; Clock Time and Real Time Relationship</caption>
+<tbody>
+<tr>
+<td>
+<slist>
+<sitem/>
+<sitem>
+<code>R = C + epochOffset + discontinuityOffset</code>
+</sitem>
+<sitem/>
+<sitem>
+where <code>C &isin; &real;</code>, <code>0 &le; C &lt; &infin;</code>, <code>C</code> in seconds since the most immediately prior midnight of the reference clock base;
+</sitem>
+<sitem/>
+<sitem>
+<code>epochOffset &isin; &real;</code>, <code>0 &le; epochOffset &lt; &infin;</code>, <code>epochOffset</code> in seconds, with 0 being the beginning
+of epoch <code>E</code>, and where the value of <code>epochOffset</code> is determined from the computed value of the <code>ttp:clockMode</code> parameter
+as follows:
+</sitem>
+<sitem/>
+<sitem>
+(1) if <code>local</code>, then the difference between the local real time at the most immediately prior local midnight and the local real time
+at the beginning of epoch <code>E</code>, expressed in seconds;
+</sitem>
+<sitem/>
+<sitem>
+(2) if <code>gps</code>, then the difference between the GPS time at the most immediately prior GPS midnight
+and the GPS time at the beginning of epoch <code>E</code>, expressed in seconds;
+</sitem>
+<sitem/>
+<sitem>
+(3) if <code>utc</code>, then the difference between the UTC time at the most immediately prior UTC midnight
+and the UTC time at the beginning of epoch <code>E</code>, expressed in seconds;
+</sitem>
+<sitem/>
+<sitem>
+<code>discontinuityOffset &isin; &real;</code>, <code>&minus;&infin; &lt; discontinuityOffset &lt; &infin;</code>, <code>discontinuityOffset</code> in seconds,
+and where the value of <code>discontinuityOffset</code> is equal to the sum of leap seconds (and fractions thereof) that have been added (or subtracted) since the
+most immediately prior midnight in the reference clock base;
+</sitem>
+<sitem/>
+<sitem>
+and <code>epochOffset</code> and <code>discontinuityOffset</code> are determined once and only once prior to the beginning of the <emph>Root Temporal Extent</emph> such that
+during the period between value determination and the beginning of the <emph>Root Temporal Extent</emph> there occurs no local midnight or reference clock base discontinuity.
+</sitem>
+<sitem/>
+</slist>
+</td>
+</tr>
+</tbody>
+</table>
+<p>Time value expressions, as denoted by a <loc href="#timing-value-timeExpression">&lt;timeExpression&gt;</loc>, are related to
+clock time <phrase role="strong"><code>C</code></phrase> as follows:</p>
+<table id="time-expressions-and-clock-time" role="semantics">
+<caption>TTML Semantics &ndash; Time Expressions and Clock Time Relationship</caption>
+<tbody>
+<tr>
+<td>
+<slist>
+<sitem/>
+<sitem>
+If a time expression uses the <emph>clock-time</emph> form or an <emph>offset-time</emph> form that doesn't use the ticks (<code>t</code>) metric, then:
+</sitem>
+<sitem/>
+<sitem>
+<code>C = 3600 * hours + 60 * minutes + seconds</code>
+</sitem>
+<sitem/>
+<sitem>
+where
+<code>hours</code>,
+<code>minutes</code>,
+<code>seconds</code> components are extracted from time expression if present, or zero if not present.
+</sitem>
+<sitem/>
+<sitem>
+Otherwise, if a time expression uses an <emph>offset-time</emph> form that uses the ticks (<code>t</code>) metric, then:
+</sitem>
+<sitem/>
+<sitem>
+<code>C = ticks / tickRate</code>
+</sitem>
+<sitem/>
+</slist>
+</td>
+</tr>
+</tbody>
+</table>
+<note role="clarification">
+<p>The <emph>frames</emph> and <emph>sub-frames</emph> terms and the frames (<code>f</code>) metric of time expressions do not apply when using
+the <code>clock</code> time base.</p>
+</note>
+<p>The clock time base <phrase role="strong"><code>C</code></phrase> is independent of media time <phrase role="strong"><code>M</code></phrase>:</p>
+<table id="clock-time-and-media-time" role="semantics">
+<caption>TTML Semantics &ndash; Clock Time and Media Time Relationship</caption>
+<tbody>
+<tr>
+<td>
+<slist>
+<sitem/>
+<sitem>
+<code>M &not;&prop; C</code>
+</sitem>
+<sitem/>
+</slist>
+</td>
+</tr>
+</tbody>
+</table>
+<note role="elaboration">
+<p>That is to say, timing is disconnected from (not necessarily proportional to) media time when
+the <code>clock</code> time base is used. For example, if the media play rate is zero (0), media playback is suspended; however, timing coordinates
+will continue to advance according to the natural progression of clock time in direct proportion to the reference clock base. Furthermore, if the media play rate changes
+during playback, presentation timing is not affected.
+</p>
+</note>
+</div2>
+<div2 id="time-expression-semantics-media">
+<head>Media Time Base</head>
+<p>When operating with the <code>media</code> time base, the following semantics should be applied for interpreting time expressions,
+as defined by <loc href="#timing-value-timeExpression">&lt;timeExpression&gt;</loc>, and their relationship to media time and local real time.</p>
+<p>The media time base <phrase role="strong"><code>M</code></phrase> is related to local real time <phrase role="strong"><code>R</code></phrase>
+expressed in an arbitrary (implementation defined) epoch <phrase role="strong"><code>E</code></phrase> as follows:</p>
+<table id="media-time-and-real-time" role="semantics">
+<caption>TTML Semantics &ndash; Media Time and Real Time Relationship</caption>
+<tbody>
+<tr>
+<td>
+<slist>
+<sitem/>
+<sitem>
+<code>R = playRate * M + epochOffset</code>
+</sitem>
+<sitem/>
+<sitem>
+where <code>M &isin; &real;</code>, <code>0 &le; M &lt; &infin;</code>, <code>M</code> in seconds, with 0 corresponding to the beginning of the <emph>Root Temporal Extent</emph>;
+</sitem>
+<sitem/>
+<sitem>
+<code>playRate &isin; &real;</code>, <code>&minus;&infin; &lt; playRate &lt; &infin;</code>, <code>playRate</code> is unit-less, and where the value of
+<code>playRate</code> is determined by the document processing context;
+</sitem>
+<sitem/>
+<sitem>
+and <code>epochOffset &isin; &real;</code>, <code>0 &le; epochOffset &lt; &infin;</code>, <code>epochOffset</code> in seconds, with 0 corresponding to the beginning of
+an epoch <code>E</code>, and where the value of <code>epochOffset</code> is the difference between the local real time at the beginning of the
+<emph>Root Temporal Extent</emph> and the local real time at the the beginning of epoch <code>E</code>, expressed in seconds.
+</sitem>
+</slist>
+</td>
+</tr>
+</tbody>
+</table>
+<p>Time value expressions, as denoted by a <loc href="#timing-value-timeExpression">&lt;timeExpression&gt;</loc>, are related to
+media time <phrase role="strong"><code>M</code></phrase> in accordance to the
+<code>ttp:frameRate</code>, <code>ttp:subFrameRate</code>, and <code>ttp:frameRateMultipler</code> parameters as follows:</p>
+<table id="time-expressions-and-media-time" role="semantics">
+<caption>TTML Semantics &ndash; Time Expressions and Media Time Relationship</caption>
+<tbody>
+<tr>
+<td>
+<slist>
+<sitem/>
+<sitem>
+If a time expression uses a <emph>clock-time</emph> form or an <emph>offset-time</emph> form that doesn't use the ticks (<code>t</code>) metric, then:
+</sitem>
+<sitem/>
+<sitem>
+<code>
+M = referenceBegin + 3600 * hours + 60 * minutes + seconds + ((frames + (subFrames / subFrameRate)) / effectiveFrameRate)
+</code>
+</sitem>
+<sitem/>
+<sitem>
+where <code>referenceBegin</code> is determined according to whether the nearest ancestor time container employs
+parallel (<code>par</code>) or sequential (<code>seq</code>) semantics: if parallel or if sequential and no prior sibling
+timed element exists, then <code>referenceBegin</code>
+is the media time that corresponds to the beginning of the nearest ancestor time container or
+zero (0) if this time container is the <emph>Root Temporal Extent</emph>; otherwise, if sequential and a prior sibling
+timed element exists, then <code>referenceBegin</code> is the media time that corresponds to the active end of the
+immediate prior sibling timed element;
+</sitem>
+<sitem/>
+<sitem>
+the <code>hours</code>, <code>minutes</code>, <code>seconds</code>, <code>frames</code>, <code>subFrames</code> components
+are extracted from time expression if present, or zero if not present;
+</sitem>
+<sitem/>
+<sitem>
+<code>subFrameRate</code> is the computed value of the <att>ttp:subFrameRate</att> parameter;
+</sitem>
+<sitem/>
+<sitem>
+and <code>effectiveFrameRate</code> (in frames per second) is <code>frameRate * frameRateMultipler</code> where
+<code>frameRate</code> is the computed value of the <att>ttp:frameRate</att> parameter and
+<code>frameRateMultipler</code> is the computed value of the <att>ttp:frameRateMultiplier</att> parameter.
+</sitem>
+<sitem/>
+<sitem>
+Otherwise, if a time expression uses an <emph>offset-time</emph> form that uses the ticks (<code>t</code>) metric, then:
+</sitem>
+<sitem/>
+<sitem>
+<code>
+M = referenceBegin + ticks / tickRate
+</code>
+</sitem>
+<sitem/>
+<sitem>
+where <code>referenceBegin</code> is as described above;
+</sitem>
+<sitem/>
+<sitem>
+the <code>ticks</code> component is extracted from time expression;
+</sitem>
+<sitem/>
+<sitem>
+and <code>tickRate</code> is the computed value of the <att>ttp:tickRate</att> parameter;
+</sitem>
+<sitem/>
+</slist>
+</td>
+</tr>
+</tbody>
+</table>
+<note role="elaboration">
+<p>If the computed <code>frameRateMultipler</code> ratio is not integral, then <code>effectiveFrameRate</code> will be a non-integral rational.</p>
+</note>
+<note role="clarification">
+<p>The above formalisms assumes that the <emph>Root Temporal Extent</emph> corresponds with the beginning of a related media object. If
+this assumption doesn't hold, then an additional offset that accounts for the difference may be introduced when computing media time <code>M</code>.</p>
+</note>
+</div2>
+<div2 id="time-expression-semantics-smpte">
+<head>SMPTE Time Base</head>
+<p>When operating with the <code>smpte</code> time base, the following semantics should be applied for interpreting time expressions,
+as defined by <loc href="#timing-value-timeExpression">&lt;timeExpression&gt;</loc>, and their relationship to media time and local real time.</p>
+<p>If the computed value of the <att>ttp:markerMode</att> parameter is <code>discontinuous</code>, then there is no direct relationship between
+time expressions and media time <phrase role="strong"><code>M</code></phrase> or local real time <phrase role="strong"><code>R</code></phrase>. In
+this case, time expressions refer to synchronization events (markers) emitted by the <emph>Document Processing Context</emph> when <emph>SMPTE Time
+Codes</emph> are encountered in the <emph>Related Media Object</emph>.</p>
+<p>Otherwise, if the computed value of the <att>ttp:markerMode</att> parameter is <code>continuous</code>, then the relationships between time expressions and
+local real time and media time are as described below in terms of a <emph>Synthetic SMPTE Document Syncbase</emph>, here referred to as the
+SMPTE time base <phrase role="strong"><code>S</code></phrase>.</p>
+<table id="time-expressions-and-smpte-time" role="semantics">
+<caption>TTML Semantics &ndash; Time Expressions and SMPTE Time Relationship</caption>
+<tbody>
+<tr>
+<td>
+<slist>
+<sitem/>
+<sitem>
+<code>S = (countedFrames - droppedFrames + (subFrames / subFrameRate)) / effectiveFrameRate</code>
+</sitem>
+<sitem/>
+<sitem>where</sitem>
+<sitem/>
+<sitem>
+<code>countedFrames = (3600 * hours + 60 * minutes + seconds) * frameRate + frames</code>
+</sitem>
+<sitem/>
+<sitem>
+<code>hours</code>, <code>minutes</code>, <code>seconds</code>, <code>frames</code>, <code>subFrames</code> components
+are extracted from time expression if present, or zero if not present;
+</sitem>
+<sitem/>
+<sitem>
+<code>droppedFrames</code> is computed as follows:
+</sitem>
+<sitem/>
+<sitem>
+1. let <emph>dropMode</emph> be the computed value of the <att>ttp:dropMode</att> parameter;
+</sitem>
+<sitem/>
+<sitem>
+2. if <emph>dropMode</emph> is <code>dropNTSC</code>, let
+<code>droppedFrames = (hours * 54 + floor(minutes - minutes/10)) * 2</code>;
+</sitem>
+<sitem/>
+<sitem>
+3. otherwise, if <emph>dropMode</emph> is <code>dropPAL</code>, let
+<code>droppedFrames = (hours * 27 + floor(minutes/2 - minutes/20)) * 4</code>;
+</sitem>
+<sitem/>
+<sitem>
+4. otherwise, let
+<code>droppedFrames = 0</code>;
+</sitem>
+<sitem/>
+<sitem>
+<code>frameRate</code> is the computed value of the <att>ttp:frameRate</att> parameter;
+</sitem>
+<sitem/>
+<sitem>
+<code>subFrameRate</code> is the computed value of the <att>ttp:subFrameRate</att> parameter;
+</sitem>
+<sitem/>
+<sitem>
+and <code>effectiveFrameRate</code> (in frames per second) is <code>frameRate * frameRateMultipler</code> where
+<code>frameRate</code> is the computed value of the <att>ttp:frameRate</att> parameter and
+<code>frameRateMultipler</code> is the computed value of the <att>ttp:frameRateMultiplier</att> parameter.
+</sitem>
+<sitem/>
+<sitem>
+Notwithstanding the above, if a time expression contains a frame code that is designated as
+dropped according to <specref ref="parameter-attribute-dropMode"/>, then that time expression
+should be considered to be invalid for purposes of validation assessment.
+</sitem>
+<sitem/>
+</slist>
+</td>
+</tr>
+</tbody>
+</table>
+<p>The SMPTE time base <phrase role="strong"><code>S</code></phrase> is related to the media time base <phrase role="strong"><code>M</code></phrase> as follows:</p>
+<table id="smpte-time-and-media-time" role="semantics">
+<caption>TTML Semantics &ndash; SMPTE Time and Media Time Relationship</caption>
+<tbody>
+<tr>
+<td>
+<slist>
+<sitem/>
+<sitem>
+<code>M = referenceBegin + S</code>
+</sitem>
+<sitem/>
+<sitem>
+where <code>referenceBegin</code> is determined according to whether the nearest ancestor time container employs
+parallel (<code>par</code>) or sequential (<code>seq</code>) semantics: if parallel or if sequential and no prior sibling
+timed element exists, then <code>referenceBegin</code>
+is the SMPTE time that corresponds to the beginning of the nearest ancestor time container or
+zero (0) if this time container is the <emph>Root Temporal Extent</emph>; otherwise, if sequential and a prior sibling
+timed element exists, then <code>referenceBegin</code> is the SMPTE time that corresponds to the active end of the
+immediate prior sibling timed element;
+</sitem>
+<sitem/>
+</slist>
+</td>
+</tr>
+</tbody>
+</table>
+<p>Given the derived media time base as described above, then 
+media time base <phrase role="strong"><code>M</code></phrase> is related to the local real time <phrase role="strong"><code>R</code></phrase>
+as described in <specref ref="time-expression-semantics-media"/> above.</p>
+</div2>
+</inform-div1>
+<inform-div1 id="common-styling">
+<head>Common Caption Style Examples</head>
+<p>This section provides examples of the following common caption styles using TTML Content
+to obtain the desired behavior:</p>
+<ulist>
+<item><p>Pop-On Captions</p></item>
+<item><p>Roll-Up Captions</p></item>
+<item><p>Paint-On Captions</p></item>
+</ulist>
+<div2 id="pop-on-example">
+<head>Pop-On Caption Example</head>
+<p>An example of paint-on captions. In this example, two regions are targeted with alternating, paint-on content, where content is timed
+using explicit sequential time containment rules. Each paragraph is non-overlapping in time and appears in the same single row
+of its targeted region.</p>
+<table id="pop-on-example-1-s" role="example">
+<caption>Example &ndash; Pop-On Captions</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">&ttml-ex2-pop-on;</eg>
+</td>
+</tr>
+</tbody>
+</table>
+</div2>
+<div2 id="roll-up-example">
+<head>Roll-Up Caption Example</head>
+<p>An example of roll-up captions. Roll-up effects are achieved by using overlapped time intervals, where zero, one, or two paragraphs appear in the region
+at a given time. Each paragraph consumes a single row (line) of the region since no wrapping occurs. Depending on whether a presentation processor supports
+<loc href="#semantics-smooth-scrolling-recommendation">smooth scrolling between adjacent synchronic intermediate document instances</loc>, the transitions, i.e., moving an
+old paragraph (line) out and a new paragraph (line) in, will be either smooth or discrete.</p>
+<table id="roll-up-example-1-s" role="example">
+<caption>Example &ndash; Roll-Up Captions</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">&ttml-ex2-roll-up;</eg>
+</td>
+</tr>
+</tbody>
+</table>
+</div2>
+<div2 id="paint-on-example">
+<head>Paint-On Caption Example</head>
+<p>An example of paint-on captions. Paint-on effects are achieved by using timed <el>span</el> elements in order to expose (paint) inline text units, e.g., words,
+over some time interval. Here, five paragraphs have their individual words sequentially timed in order to paint one new word every second. The end of the active duration of
+each inline element coincides with the end of the <el>div</el> element's parallel time container, so that once a word is painted, it remains in the region (on its rendered line) until the <el>div</el> element's active time interval lapses.</p>
+<table id="paint-on-example-1-s" role="example">
+<caption>Example &ndash; Paint-On Captions</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">&ttml-ex2-paint-on;</eg>
+</td>
+</tr>
+</tbody>
+</table>
+</div2>
+</inform-div1>
+&acknowledgements;
+</back>
+</spec>
--- a/ttml11/spec/xmlspec-ttml11.dtd	Tue Jul 09 11:28:27 2013 -0600
+++ b/ttml11/spec/xmlspec-ttml11.dtd	Tue Jul 09 14:39:28 2013 -0600
@@ -31,5 +31,3 @@
 
 <!-- element definition overrides -->
 <!ELEMENT loc (#PCDATA|phrase|el|att|code|emph)*>
-
-
--- a/ttml11/spec/xmlspec-ttml11.xsl	Tue Jul 09 11:28:27 2013 -0600
+++ b/ttml11/spec/xmlspec-ttml11.xsl	Tue Jul 09 14:39:28 2013 -0600
@@ -4,8 +4,10 @@
 <xsl:import href="changelog.xsl"/>
 <xsl:param name="toc.level" select="5"/>
 <xsl:param name="show.ednotes">1</xsl:param>
+<!-- [GA] remove 2013-05-09
 <xsl:param name="show.diff.markup">1</xsl:param>
-<xsl:variable name="output.mode" select="'xhtml'"/>
+-->
+<xsl:variable name="output.mode" select="'html'"/>
 <xsl:param name="additional.css">
 <xsl:text>
 li p { margin-top: 0.3em; margin-bottom: 0.3em; }
@@ -26,10 +28,26 @@
 table.syntax th { border: 0px solid black; text-align: left }
 table.syntax td { border: 0px solid black }
 table.syntax div { background-color: #ffffc8 }
+table.semantics { border: 0px solid black; width: 85%; border-collapse: collapse }
+table.semantics caption { font-weight: bold; text-align: left; padding-bottom: 0.5em }
+table.semantics th { border: 0px solid black; text-align: left }
+table.semantics td {
+  border-left: 0px solid black;
+  border-right: 0px solid black;
+  border-top: 4px double #d3d3d3;
+  border-bottom: 4px double #d3d3d3;
+  background-color: #ccffcc
+}
+table.semantics code.formulae {
+  padding: 1em;
+  border: 1px dashed #005a9c;
+  line-height: 1.1em;
+  background-color: #fdfdfd;
+}
 table.example { border: 0px solid black; width: 85%; border-collapse: collapse }
 table.example caption { font-weight: bold; text-align: left; padding-bottom: 0.5em }
 table.example th { border: 0px solid black; text-align: left }
-table.example td { border: 0px solid black }
+table.example td { border: 0px solid black;  }
 table.example div { background-color: #c8ffff }
 table.example-images { text-align: center; border: 0px solid black; width: 85%; border-collapse: collapse }
 table.example-images caption { font-weight: bold; text-align: center; padding-bottom: 0.5em }
@@ -42,144 +60,20 @@
 .reqattr { font-weight: bold }
 .optattr { font-style: italic }
 </xsl:text>
-<xsl:if test="$show.diff.markup != '0'">
-<xsl:text>
-.diff-add  { color: red; background-color: #99FF99; }
-.diff-del  { color: red; text-decoration: line-through; background-color: #99FF99; }
-.diff-chg  { background-color: #99FF99; }
-q.diff-off  {}
-</xsl:text>
-</xsl:if>
 </xsl:param>
-<xsl:output method="xml" encoding="utf-8" doctype-public="-//W3C//DTD XHTML 1.0 Transitional//EN" doctype-system="http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd" indent="no"/>
-
-<!-- [GA] removed the following overrides: -->
-<!-- inform-div1[head='Change Log']/p -->
-<!-- bibref -->
-<!-- bibl -->
-<!-- titleref -->
-<!-- emph[@role='infoset-property'] -->
-<!-- ulist[@role='termreference'] -->
-<!-- eg[@role='needs-numbering'] -->
-<!-- addLineNumbers -->
-<!-- lb mode(addLineNumbers) -->
-<!-- node() mode(addLineNumbers) -->
-<!-- code[@role='code-emph'] -->
-<!-- p[@role='practice'] -->
-<!-- p[@role='practice'] mode(number) -->
-<!-- css -->
-<!-- specref -->
+<xsl:output method="html" encoding="utf-8" indent="no"/>
 
-<!-- [GA] added the following overrides from old DFXP CR1 spec sources -->
-<!-- diff support -->
-<xsl:template name="diff-markup">
-  <xsl:param name="diff">off</xsl:param>
-  <xsl:choose>
-    <xsl:when test="self::ritem">
-	<xsl:apply-templates select="." mode="diff"/>
-    </xsl:when>
-    <xsl:when test="self::ulist or self::p or self::bibl">
-      <xsl:apply-templates/>
-    </xsl:when>
-    <xsl:when test="ancestor-or-self::phrase">
-      <span xmlns="http://www.w3.org/1999/xhtml" class="diff-{$diff}">
-	<xsl:apply-templates/>
-      </span>
-    </xsl:when>
-    <xsl:when test="ancestor::p and not(self::p)">
-      <span xmlns="http://www.w3.org/1999/xhtml" class="diff-{$diff}">
-	<xsl:apply-templates/>
-      </span>
-    </xsl:when>
-    <xsl:when test="ancestor-or-self::affiliation">
-      <span xmlns="http://www.w3.org/1999/xhtml" class="diff-{$diff}">
-	<xsl:apply-templates/>
-      </span>
-    </xsl:when>
-    <xsl:when test="ancestor-or-self::name">
-      <span xmlns="http://www.w3.org/1999/xhtml" class="diff-{$diff}">
-	<xsl:apply-templates/>
-      </span>
-    </xsl:when>
-    <xsl:when test="ancestor-or-self::note">
-      <div xmlns="http://www.w3.org/1999/xhtml" class="diff-{$diff}">
-	<div class="note">
-	  <p class="prefix">
-	    <b>Note:</b>
-	  </p>
-	  <xsl:apply-templates/>
-        </div>
-      </div>
-    </xsl:when>
-    <xsl:otherwise>
-      <div xmlns="http://www.w3.org/1999/xhtml" class="diff-{$diff}">
-	<xsl:apply-templates/>
-      </div>
-    </xsl:otherwise>
-  </xsl:choose>
-</xsl:template>
-<xsl:template match="*[@diff='chg']">
-  <xsl:choose>
-    <xsl:when test="$show.diff.markup != 0">
-      <xsl:call-template name="diff-markup">
-	<xsl:with-param name="diff">chg</xsl:with-param>
-      </xsl:call-template>
-    </xsl:when>
-    <xsl:otherwise>
-      <xsl:apply-templates/>
-    </xsl:otherwise>
-  </xsl:choose>
-</xsl:template>
-<xsl:template match="*[@diff='add']">
-  <xsl:choose>
-    <xsl:when test="$show.diff.markup != 0">
-      <xsl:call-template name="diff-markup">
-	<xsl:with-param name="diff">add</xsl:with-param>
-      </xsl:call-template>
-    </xsl:when>
-    <xsl:otherwise>
-      <xsl:apply-templates/>
-    </xsl:otherwise>
-  </xsl:choose>
-</xsl:template>
-<xsl:template match="*[@diff='del']">
-  <xsl:choose>
-    <xsl:when test="$show.diff.markup != 0">
-      <xsl:call-template name="diff-markup">
-	<xsl:with-param name="diff">del</xsl:with-param>
-      </xsl:call-template>
-    </xsl:when>
-    <xsl:otherwise>
-      <!-- suppress deleted markup -->
-    </xsl:otherwise>
-  </xsl:choose>
-</xsl:template>
-<xsl:template match="*[@diff='off']">
-  <xsl:choose>
-    <xsl:when test="$show.diff.markup != 0">
-      <xsl:call-template name="diff-markup">
-	<xsl:with-param name="diff">off</xsl:with-param>
-      </xsl:call-template>
-    </xsl:when>
-    <xsl:otherwise>
-      <xsl:apply-templates/>
-    </xsl:otherwise>
-  </xsl:choose>
-</xsl:template>
 <!-- spec: the specification itself -->
 <xsl:template match="spec">
-  <html xmlns="http://www.w3.org/1999/xhtml">
+  <html>
     <xsl:if test="header/langusage/language">
-      <xsl:attribute name="xml:lang">
-	<xsl:value-of select="header/langusage/language/@id"/>
-      </xsl:attribute>
       <xsl:attribute name="lang">
 	<xsl:value-of select="header/langusage/language/@id"/>
       </xsl:attribute>
     </xsl:if>
     <head>
-      <xsl:if test="$output.mode='xhtml'">
-	<meta http-equiv="Content-Type" content="application/xhtml+xml; charset=utf-8"/>
+      <xsl:if test="$output.mode='html'">
+	<meta http-equiv="Content-Type" content="text/html; charset=utf-8"/>
       </xsl:if>
       <title>
 	<xsl:apply-templates select="header/title"/>
@@ -192,15 +86,16 @@
 	  <xsl:value-of select="$additional.title"/>
 	</xsl:if>
 	<xsl:if test="/spec/@role='editors-copy'">
-	  <xsl:text> -- (Editors' copy)</xsl:text>
+	  <xsl:text> -- (Editor's copy)</xsl:text>
 	</xsl:if>
       </title>
       <xsl:call-template name="css"/>
+      <xsl:call-template name="additional-head"/>
     </head>
     <body>
       <xsl:if test="/spec/@role='editors-copy'">
 	<xsl:value-of select="//revisiondesc/p[1]"/>
-	<div id="revisions"/>
+	<div id="revisions"></div>
       </xsl:if>
       <xsl:apply-templates/>
       <xsl:if test="//footnote[not(ancestor::table)]">
@@ -222,55 +117,56 @@
     </body>
   </html>
 </xsl:template>
-<!-- status: the status of the spec -->
-<xsl:template match="status">
-  <div xmlns="http://www.w3.org/1999/xhtml">
-    <h2>
-      <xsl:call-template name="anchor">
-	<xsl:with-param name="conditional" select="0"/>
-	<xsl:with-param name="default.id" select="'status'"/>
-      </xsl:call-template>
-      <xsl:text>Status of this Document</xsl:text>
-    </h2>
-    <xsl:if test="/spec/@role='editors-copy'">
-      <p><strong>This document is an editor's copy that has no official standing.</strong></p>
-    </xsl:if>
-    <xsl:apply-templates/>
-  </div>
-</xsl:template>
-<!-- specref: reference to another part of the current specification -->
+
+<!-- specref: reference to another part of teh current specification -->
 <xsl:template match="specref">
-  <xsl:variable name="target" select="key('ids', @ref)[1]"/>
+  <xsl:param name="target" select="key('ids', @ref)[1]"/>
+
   <xsl:choose>
-    <xsl:when test="local-name($target)='issue' or starts-with(local-name($target), 'div') or starts-with(local-name($target), 'inform-div') or local-name($target) = 'vcnote' or local-name($target) = 'prod' or local-name($target) = 'label' or local-name($target) = 'ritem' or local-name($target) = 'table'">
+    <xsl:when test="not($target)">
+      <xsl:message>
+        <xsl:text>specref to non-existent ID: </xsl:text>
+        <xsl:value-of select="@ref"/>
+      </xsl:message>
+    </xsl:when>
+    <xsl:when test="local-name($target)='issue'
+                    or starts-with(local-name($target), 'div')
+                    or starts-with(local-name($target), 'inform-div')
+                    or local-name($target) = 'vcnote'
+                    or local-name($target) = 'prod'
+                    or local-name($target) = 'example'
+                    or local-name($target) = 'label'
+                    or local-name($target) = 'table'
+                    or $target/self::item[parent::olist]">
       <xsl:apply-templates select="$target" mode="specref"/>
     </xsl:when>
     <xsl:otherwise>
       <xsl:message>
-	<xsl:text>Unsupported specref to </xsl:text>
-	<xsl:value-of select="local-name($target)"/>
-	<xsl:text> [</xsl:text>
-	<xsl:value-of select="@ref"/>
-	<xsl:text>] </xsl:text>
-	<xsl:text> (Contact stylesheet maintainer).</xsl:text>
+        <xsl:text>Unsupported specref to </xsl:text>
+        <xsl:value-of select="local-name($target)"/>
+        <xsl:text> [</xsl:text>
+        <xsl:value-of select="@ref"/>
+        <xsl:text>] </xsl:text>
+        <xsl:text> (Contact stylesheet maintainer).</xsl:text>
       </xsl:message>
-      <b xmlns="http://www.w3.org/1999/xhtml">
-	<a>
-	  <xsl:attribute name="href">
-	    <xsl:call-template name="href.target">
-	      <xsl:with-param name="target" select="key('ids', @ref)"/>
-	    </xsl:call-template>
-	  </xsl:attribute>
-	  <xsl:text>???</xsl:text>
-	</a>
+      <b>
+        <a>
+          <xsl:attribute name="href">
+            <xsl:call-template name="href.target">
+              <xsl:with-param name="target" select="key('ids', @ref)"/>
+            </xsl:call-template>
+          </xsl:attribute>
+          <xsl:text>???</xsl:text>
+        </a>
       </b>
     </xsl:otherwise>
   </xsl:choose>
 </xsl:template>
+
 <!-- ednote: editors' note -->
 <xsl:template match="ednote">
   <xsl:if test="$show.ednotes != 0">
-    <table xmlns="http://www.w3.org/1999/xhtml" border="1" class="ednote" summary="Editor's Notes">
+    <table border="1" class="ednote" summary="Editor's Notes">
       <xsl:attribute name="summary">
 	<xsl:text>Editorial note</xsl:text>
 	<xsl:if test="name">
@@ -293,7 +189,7 @@
 	    <xsl:when test="date">
 	      <xsl:apply-templates select="date"/>
 	    </xsl:when>
-	    <xsl:otherwise> </xsl:otherwise>
+	    <xsl:otherwise>&#160;</xsl:otherwise>
 	  </xsl:choose>
 	</td>
       </tr>
@@ -305,11 +201,12 @@
     </table>
   </xsl:if>
 </xsl:template>
+
 <!-- glist: glossary list -->
 <xsl:template match="glist">
   <xsl:choose>
   <xsl:when test="@role = 'acronyms'">
-    <table xmlns="http://www.w3.org/1999/xhtml" class="acronyms" summary="Glossary List">
+    <table class="acronyms" summary="Glossary List">
       <xsl:for-each select="gitem">
         <tr>
           <xsl:apply-templates select="label" mode="acronym"/>
@@ -322,7 +219,7 @@
       <xsl:if test="$validity.hacks = 1 and local-name(..) = 'p'">
 	<xsl:text disable-output-escaping="yes">&lt;/p&gt;</xsl:text>
       </xsl:if>
-      <dl xmlns="http://www.w3.org/1999/xhtml">
+      <dl>
 	<xsl:if test="@role">
 	  <xsl:attribute name="class">
 	    <xsl:value-of select="@role"/>
@@ -336,9 +233,10 @@
     </xsl:otherwise>
   </xsl:choose>
 </xsl:template>
+
 <!-- label: acronym mode -->
 <xsl:template mode="acronym" match="label">
-  <td xmlns="http://www.w3.org/1999/xhtml" class="label">
+  <td class="label">
     <xsl:call-template name="anchor">
       <xsl:with-param name="node" select=".."/>
     </xsl:call-template>
@@ -346,15 +244,29 @@
     <b><xsl:apply-templates/></b>
   </td>
 </xsl:template>
+
+<!-- code: generic computer code (override to map @role) -->
+<xsl:template match="code">
+  <code>
+    <xsl:if test="@role">
+      <xsl:attribute name="class">
+        <xsl:value-of select="@role"/>
+      </xsl:attribute>
+    </xsl:if>
+    <xsl:apply-templates/>
+  </code>
+</xsl:template>
+
 <!-- def: acronym mode -->
 <xsl:template mode="acronym" match="def">
-  <td xmlns="http://www.w3.org/1999/xhtml" class="def">
+  <td class="def">
   <xsl:apply-templates/>
   </td>
 </xsl:template>
+
 <!-- loc: a Web location -->
 <xsl:template match="loc">
-  <a xmlns="http://www.w3.org/1999/xhtml" href="{@href}">
+  <a href="{@href}">
     <xsl:if test="@role">
       <xsl:attribute name="rel">
 	<xsl:value-of select="@role"/>
@@ -363,295 +275,25 @@
     <xsl:apply-templates/>
   </a>
 </xsl:template>
-<!-- rlist: requirement list -->
-<xsl:template match="rlist">
-  <dl xmlns="http://www.w3.org/1999/xhtml">
-    <xsl:apply-templates/>
-  </dl>
-</xsl:template>
-<!-- ritem: requirement item -->
-<xsl:template match="ritem">
-  <xsl:variable name="this-req-id">
-    <xsl:choose>
-      <xsl:when test="@id">
-	<xsl:value-of select="@id"/>
-      </xsl:when>
-      <xsl:otherwise>
-	<xsl:value-of select="generate-id(.)"/>
-      </xsl:otherwise>
-    </xsl:choose>
-  </xsl:variable>
-  <dt xmlns="http://www.w3.org/1999/xhtml">
+
+<!-- note: a note about the spec (override to map @id) -->
+<xsl:template match="note">
+  <div class="note">
     <xsl:if test="@id">
-      <a name="{@id}" id="{@id}"/>
+      <xsl:attribute name="id">
+        <xsl:value-of select="@id"/>
+      </xsl:attribute>
     </xsl:if>
-    <xsl:value-of select="$this-req-id"/>
-    <xsl:text disable-output-escaping="yes"> &#38;ndash; </xsl:text>
-    <xsl:apply-templates select="head" mode="text"/>
-  </dt>
-  <dd xmlns="http://www.w3.org/1999/xhtml">
-    <xsl:apply-templates select="req"/>
-  </dd>
-</xsl:template>
-<!-- ritem: requirement item; mode(diff) -->
-<xsl:template match="ritem" mode="diff">
-  <xsl:variable name="diffval" select="ancestor-or-self::*/@diff"/>
-  <xsl:variable name="this-req-id">
-    <xsl:choose>
-      <xsl:when test="@id">
-	<xsl:value-of select="@id"/>
-      </xsl:when>
-      <xsl:otherwise>
-	<xsl:value-of select="generate-id(.)"/>
-      </xsl:otherwise>
-    </xsl:choose>
-  </xsl:variable>
-  <xsl:choose>
-    <xsl:when test="$diffval='del' and $show.diff.markup = 0">
-      <!-- delete item -->
-    </xsl:when>
-    <xsl:otherwise>
-      <dt xmlns="http://www.w3.org/1999/xhtml" class="diff-{$diffval}">
-	<xsl:if test="@id">
-	  <a name="{@id}" id="{@id}"/>
-	</xsl:if>
-	<xsl:value-of select="$this-req-id"/>
-	<xsl:text disable-output-escaping="yes"> &#38;ndash; </xsl:text>
-	<xsl:apply-templates select="head" mode="text"/>
-      </dt>
-      <dd xmlns="http://www.w3.org/1999/xhtml" class="diff-{$diffval}">
-	<xsl:apply-templates select="req"/>
-      </dd>
-    </xsl:otherwise>
-  </xsl:choose>
-</xsl:template>
-<xsl:template match="ritem" mode="specref">
-  <a xmlns="http://www.w3.org/1999/xhtml">
-    <xsl:attribute name="href">
-      <xsl:call-template name="href.target"/>
-    </xsl:attribute>
-    <b>
-      <xsl:apply-templates select="head" mode="text"/>
-    </b>
-  </a>
-</xsl:template>
-<!-- req: requirement body -->
-<xsl:template match="req">
-  <div xmlns="http://www.w3.org/1999/xhtml" class="req">
-    <xsl:apply-templates/>
-  </div>
-</xsl:template>
-<!-- uselist: use case scenario list -->
-<xsl:template match="uselist">
-  <dl xmlns="http://www.w3.org/1999/xhtml">
-    <xsl:apply-templates/>
-  </dl>
-</xsl:template>
-<!-- useitem: use case scenario item -->
-<xsl:template match="useitem">
-  <xsl:variable name="this-use-id">
-    <xsl:choose>
-      <xsl:when test="@id">
-	<xsl:value-of select="@id"/>
-      </xsl:when>
-      <xsl:otherwise>
-	<xsl:value-of select="generate-id(.)"/>
-      </xsl:otherwise>
-    </xsl:choose>
-  </xsl:variable>
-  <dt xmlns="http://www.w3.org/1999/xhtml">
-    <xsl:if test="@id">
-      <a name="{@id}" id="{@id}"/>
-    </xsl:if>
-    <xsl:value-of select="$this-use-id"/>
-    <xsl:text disable-output-escaping="yes"> &#38;ndash; </xsl:text>
-    <xsl:apply-templates select="head" mode="text"/>
-  </dt>
-  <dd xmlns="http://www.w3.org/1999/xhtml">
-    <xsl:apply-templates select="use"/>
-  </dd>
-</xsl:template>
-<xsl:template match="useitem" mode="specref">
-  <a xmlns="http://www.w3.org/1999/xhtml">
-    <xsl:attribute name="href">
-      <xsl:call-template name="href.target"/>
-    </xsl:attribute>
-    <b>
-      <xsl:apply-templates select="head" mode="text"/>
-    </b>
-  </a>
-</xsl:template>
-<!-- use: use case scenario body -->
-<xsl:template match="use">
-  <div xmlns="http://www.w3.org/1999/xhtml" class="use">
+    <p class="prefix">
+      <b>Note:</b>
+    </p>
     <xsl:apply-templates/>
   </div>
 </xsl:template>
-<!-- status w/diff -->
-<xsl:template match="status[@diff]" priority="1">
-  <xsl:variable name="diffval" select="ancestor-or-self::*/@diff"/>
-  <xsl:if test='$show.diff.markup != 0 or $diffval != "del"'>
-    <div xmlns="http://www.w3.org/1999/xhtml">
-      <xsl:if test='$show.diff.markup != 0'>
-	<xsl:attribute name='class'>
-	  <xsl:text>diff-</xsl:text>
-	  <xsl:value-of select='$diffval'/>
-	</xsl:attribute>
-      </xsl:if>
-      <h2>
-	<xsl:call-template name="anchor">
-	  <xsl:with-param name="conditional" select="0"/>
-	  <xsl:with-param name="default.id" select="'status'"/>
-	</xsl:call-template>
-	<xsl:text>Status of this Document</xsl:text>
-      </h2>
-      <xsl:if test="/spec/@role='editors-copy'">
-	<p><strong>This document is an editor's copy that has no official standing.</strong></p>
-      </xsl:if>
-      <xsl:apply-templates/>
-    </div>
-  </xsl:if>
-</xsl:template>
-<!-- note w/diff -->
-<xsl:template match="note[@diff]" priority="1">
-  <xsl:variable name="diffval" select="ancestor-or-self::*/@diff"/>
-  <xsl:if test='$show.diff.markup != 0 or $diffval != "del"'>
-    <div xmlns="http://www.w3.org/1999/xhtml">
-      <xsl:if test='$show.diff.markup != 0'>
-	<xsl:attribute name='class'>
-	  <xsl:text>diff-</xsl:text>
-	  <xsl:value-of select='$diffval'/>
-	</xsl:attribute>
-      </xsl:if>
-      <div class="note">
-	<p class="prefix">
-	  <b>Note:</b>
-	</p>
-	<xsl:apply-templates/>
-      </div>
-    </div>
-  </xsl:if>
-</xsl:template>
-<!-- ulist w/diff -->
-<xsl:template match="ulist[@diff]" priority="1">
-  <xsl:variable name="diffval" select="ancestor-or-self::*/@diff"/>
-  <xsl:if test='$show.diff.markup != 0 or $diffval != "del"'>
-    <ul xmlns="http://www.w3.org/1999/xhtml">
-      <xsl:if test='$show.diff.markup != 0'>
-	<xsl:attribute name='class'>
-	  <xsl:text>diff-</xsl:text>
-	  <xsl:value-of select='$diffval'/>
-	</xsl:attribute>
-      </xsl:if>
-      <xsl:apply-templates/>
-    </ul>
-  </xsl:if>
-</xsl:template>
-<!-- p w/diff -->
-<xsl:template match="p[@diff]" priority="1">
-  <xsl:variable name="diffval" select="ancestor-or-self::*/@diff"/>
-  <xsl:if test='$show.diff.markup != 0 or $diffval != "del"'>
-    <p xmlns="http://www.w3.org/1999/xhtml">
-      <xsl:if test='$show.diff.markup != 0'>
-	<xsl:attribute name='class'>
-	  <xsl:text>diff-</xsl:text>
-	  <xsl:value-of select='$diffval'/>
-	</xsl:attribute>
-      </xsl:if>
-      <xsl:if test="@id">
-	<xsl:attribute name="id">
-	  <xsl:value-of select="@id"/>
-	</xsl:attribute>
-      </xsl:if>
-      <xsl:if test="@role">
-	<xsl:attribute name="class">
-	  <xsl:value-of select="@role"/>
-	</xsl:attribute>
-      </xsl:if>
-      <xsl:apply-templates/>
-    </p>
-  </xsl:if>
-</xsl:template>
-<!-- bibl w/diff -->
-<xsl:template match="bibl[@diff]" priority="1">
-  <xsl:variable name="diffval" select="ancestor-or-self::*/@diff"/>
-  <xsl:if test='$show.diff.markup != 0 or $diffval != "del"'>
-    <dt xmlns="http://www.w3.org/1999/xhtml">
-      <xsl:attribute name='class'>
-	<xsl:text>label</xsl:text>
-	<xsl:if test='$show.diff.markup != 0'>
-	  <xsl:text>diff-</xsl:text>
-	  <xsl:value-of select='$diffval'/>
-	</xsl:if>
-      </xsl:attribute>
-      <xsl:if test="@id">
-	<a name="{@id}" id="{@id}"/>
-      </xsl:if>
-      <xsl:choose>
-	<xsl:when test="@key">
-	  <xsl:value-of select="@key"/>
-	</xsl:when>
-	<xsl:otherwise>
-	  <xsl:value-of select="@id"/>
-	</xsl:otherwise>
-      </xsl:choose>
-    </dt>
-    <dd xmlns="http://www.w3.org/1999/xhtml">
-      <xsl:if test='$show.diff.markup != 0'>
-	<xsl:attribute name='class'>
-	  <xsl:text>diff-</xsl:text>
-	  <xsl:value-of select='$diffval'/>
-	</xsl:attribute>
-      </xsl:if>
-      <xsl:choose>
-	<xsl:when test="@href">
-	  <a href="{@href}">
-	    <xsl:apply-templates/>
-	  </a>
-	</xsl:when>
-	<xsl:otherwise>
-	  <xsl:apply-templates/>
-	</xsl:otherwise>
-      </xsl:choose>
-      <xsl:if test="@href">
-	<xsl:text>  (See </xsl:text>
-	<xsl:value-of select="@href"/>
-	<xsl:text>.)</xsl:text>
-      </xsl:if>
-    </dd>
-  </xsl:if>
-</xsl:template>
-<!-- table -->
-<xsl:template match="table">
-  <table xmlns="http://www.w3.org/1999/xhtml" summary="HTML Table">
-    <xsl:for-each select="@*">
-      <xsl:choose>
-	<xsl:when test="local-name(.) = 'diff'"/>
-	<xsl:when test="local-name(.) = 'role'">
-	  <xsl:attribute name="class">
-	    <xsl:value-of select="."/>
-	  </xsl:attribute>
-	</xsl:when>
-	<xsl:otherwise>
-	  <xsl:copy-of select="."/>
-	</xsl:otherwise>
-      </xsl:choose>
-    </xsl:for-each>
-    <xsl:apply-templates/>
-    <xsl:if test=".//footnote">
-      <tbody>
-	<tr>
-	  <td>
-	    <xsl:apply-templates select=".//footnote" mode="table.notes"/>
-	  </td>
-	</tr>
-      </tbody>
-    </xsl:if>
-  </table>
-</xsl:template>
+
 <!-- table specref -->
 <xsl:template match="table" mode="specref">
-  <a xmlns="http://www.w3.org/1999/xhtml">
+  <a>
     <xsl:attribute name="href">
       <xsl:call-template name="href.target"/>
     </xsl:attribute>
@@ -660,14 +302,10 @@
     </b>
   </a>
 </xsl:template>
-<!-- br: explicit line break -->
-<xsl:template match="br">
-  <br xmlns="http://www.w3.org/1999/xhtml" />
-</xsl:template>
 
 <!-- authlist -->
 <xsl:template match="authlist">
-  <dt xmlns="http://www.w3.org/1999/xhtml">
+  <dt>
     <xsl:choose>
       <xsl:when test="@role='editor'">
 	<xsl:text>Editor</xsl:text>
@@ -686,4 +324,5 @@
   </dt>
   <xsl:apply-templates/>
 </xsl:template>
+
 </xsl:stylesheet>
--- a/ttml11/spec/xmlspec.dtd	Tue Jul 09 11:28:27 2013 -0600
+++ b/ttml11/spec/xmlspec.dtd	Tue Jul 09 14:39:28 2013 -0600
@@ -2,7 +2,7 @@
 <!-- XML specification DTD ......................................... -->
 <!-- ............................................................... -->
 
-<!-- $Id$ -->
+<!-- $Id: xmlspec.dtd,v 1.20 2005/10/13 15:30:39 NormanWalsh Exp $ -->
 
 <!--
 TYPICAL INVOCATION:
--- a/ttml11/spec/xmlspec.xsl	Tue Jul 09 11:28:27 2013 -0600
+++ b/ttml11/spec/xmlspec.xsl	Tue Jul 09 14:39:28 2013 -0600
@@ -1,12 +1,13 @@
-<?xml version="1.0" encoding="utf-8"?>
-<!--This file was created automatically by html2xhtml-->
-<!--from the HTML stylesheets. Do not edit this file.-->
-<xsl:transform xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:saxon="http://icl.com/saxon" exclude-result-prefixes="saxon" version="1.0">
+<?xml version="1.0"?>
+<xsl:transform xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
+               xmlns:saxon="http://icl.com/saxon"
+               exclude-result-prefixes="saxon"
+               version="1.0">
 
 <!-- ====================================================================== -->
 <!-- xmlspec.xsl: An HTML XSL[1] Stylesheet for XML Spec V2.1[2] markup
 
-     Version: $Id$
+     Version: $Id: xmlspec.xsl,v 1.1 2011/09/07 14:47:12 mdw Exp $
 
      URI:     http://dev.w3.org/cvsweb/spec-prod/html/xmlspec.xsl
 
@@ -17,7 +18,7 @@
               Henry S. Thompson (ht@cogsci.ed.ac.uk)
 
      Date:    Created 07 September 1999
-              Last updated $Date$ by $Author$
+              Last updated $Date: 2011/09/07 14:47:12 $ by $Author: mdw $
 
      Copyright (C) 2000, 2001, 2002 Sun Microsystems, Inc. All Rights Reserved.
      This document is governed by the W3C Software License[3] as
@@ -128,7 +129,17 @@
 
   <xsl:preserve-space elements="*"/>
 
-  <xsl:strip-space elements="    abstract arg attribute authlist author back bibref blist body case col    colgroup component constant constraint constraintnote copyright def    definitions descr div div1 div2 div3 div4 div5 ednote enum enumerator    example exception footnote front gitem glist graphic group header    htable htbody inform-div1 interface issue item itemizedlist langusage    listitem member method module note notice ol olist orderedlist orglist    param parameters prod prodgroup prodrecap proto pubdate pubstmt raises    reference resolution returns revisiondesc scrap sequence slist    sourcedesc spec specref status struct table tbody tfoot thead tr    typedef ul ulist union vc vcnote wfc wfcnote"/>
+  <xsl:strip-space elements="
+   abstract arg attribute authlist author back bibref blist body case col
+   colgroup component constant constraint constraintnote copyright def
+   definitions descr div div1 div2 div3 div4 div5 ednote enum enumerator
+   example exception footnote front gitem glist graphic group header
+   htable htbody inform-div1 interface issue item itemizedlist langusage
+   listitem member method module note notice ol olist orderedlist orglist
+   param parameters prod prodgroup prodrecap proto pubdate pubstmt raises
+   reference resolution returns revisiondesc scrap sequence slist
+   sourcedesc spec specref status struct table tbody tfoot thead tr
+   typedef ul ulist union vc vcnote wfc wfcnote"/>
 
   <xsl:param name="validity.hacks" select="1"/>
   <xsl:param name="show.diff.markup" select="0"/>
@@ -142,7 +153,10 @@
   <xsl:key name="ids" match="*[@id]" use="@id"/>
   <xsl:key name="specrefs" match="specref" use="@ref"/>
 
-  <xsl:output method="xml" encoding="UTF-8" doctype-public="-//W3C//DTD XHTML 1.0 Transitional//EN" indent="no" doctype-system="http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"/>
+  <xsl:output method="html"
+       encoding="utf-8"
+       doctype-public="-//W3C//DTD HTML 4.01 Transitional//EN"
+       indent="no"/>
 
   <!-- not handled:
     attribute:   unhandled IDL stuff
@@ -182,7 +196,7 @@
       <xsl:text>.</xsl:text>
     </xsl:message>
 
-    <font xmlns="http://www.w3.org/1999/xhtml" color="red">
+    <font color="red">
       <xsl:text>&lt;</xsl:text>
       <xsl:value-of select="name(.)"/>
       <xsl:text>&gt;</xsl:text>
@@ -209,9 +223,8 @@
   <!-- format as a second-level div -->
   <!-- called in enforced order from header's template -->
   <xsl:template match="abstract">
-    <div xmlns="http://www.w3.org/1999/xhtml">
-      <xsl:text>
-</xsl:text>
+    <div>
+      <xsl:text>&#10;</xsl:text>
       <h2>
         <xsl:call-template name="anchor">
           <xsl:with-param name="conditional" select="0"/>
@@ -238,7 +251,7 @@
     <xsl:if test="preceding-sibling::arg">
       <xsl:text>, </xsl:text>
     </xsl:if>
-    <var xmlns="http://www.w3.org/1999/xhtml">
+    <var>
       <xsl:value-of select="@type"/>
     </var>
     <xsl:if test="@occur = 'opt'">
@@ -250,7 +263,7 @@
   <!-- used lots of places -->
   <!-- format as monospaced code -->
   <xsl:template match="att">
-    <code xmlns="http://www.w3.org/1999/xhtml"><xsl:apply-templates/></code>
+    <code><xsl:apply-templates/></code>
   </xsl:template>
 
   <!-- attribute: -->
@@ -269,9 +282,9 @@
   <!-- called in enforced order from header's template, in <dl>
        context -->
   <xsl:template match="authlist">
-    <dt xmlns="http://www.w3.org/1999/xhtml">
+    <dt>
       <xsl:text>Editor</xsl:text>
-      <xsl:if test="count(author) &gt; 1">
+      <xsl:if test="count(author) > 1">
         <xsl:text>s</xsl:text>
       </xsl:if>
       <xsl:text>:</xsl:text>
@@ -283,7 +296,7 @@
   <!-- only appears in authlist -->
   <!-- called in <dl> context -->
   <xsl:template match="author">
-    <dd xmlns="http://www.w3.org/1999/xhtml">
+    <dd>
       <xsl:apply-templates/>
       <xsl:if test="@role = '2e'">
         <xsl:text> - Second Edition</xsl:text>
@@ -295,7 +308,7 @@
   <!-- make a <div> for neatness -->
   <!-- affects numbering of div1 children -->
   <xsl:template match="back">
-    <div xmlns="http://www.w3.org/1999/xhtml" class="back">
+    <div class="back">
       <xsl:apply-templates/>
       <xsl:call-template name="autogenerated-appendices"/>
     </div>
@@ -307,9 +320,9 @@
   <!-- if there's a key, use it in the <dt>, otherwise use the ID -->
   <!-- if there's an href, add a ref in parens at the end of the text -->
   <xsl:template match="bibl">
-    <dt xmlns="http://www.w3.org/1999/xhtml" class="label">
+    <dt class="label">
       <xsl:if test="@id">
-        <a name="{@id}" id="{@id}"/>
+        <a id="{@id}"/>
       </xsl:if>
       <xsl:choose>
         <xsl:when test="@key">
@@ -320,7 +333,7 @@
         </xsl:otherwise>
       </xsl:choose>
     </dt>
-    <dd xmlns="http://www.w3.org/1999/xhtml">
+    <dd>
       <xsl:apply-templates/>
       <xsl:if test="@href">
         <xsl:text>  (See </xsl:text>
@@ -335,7 +348,7 @@
   <!-- if the bibl has a key, put it in square brackets; otherwise use
        the bibl's ID -->
   <xsl:template match="bibref">
-    <a xmlns="http://www.w3.org/1999/xhtml">
+    <a>
       <xsl:attribute name="href">
         <xsl:call-template name="href.target">
           <xsl:with-param name="target" select="key('ids', @ref)"/>
@@ -357,7 +370,7 @@
   <!-- blist: list of bibliographic entries -->
   <!-- set up the list and process children -->
   <xsl:template match="blist">
-    <dl xmlns="http://www.w3.org/1999/xhtml">
+    <dl>
       <xsl:apply-templates/>
     </dl>
   </xsl:template>
@@ -366,7 +379,7 @@
   <!-- preformatted within a table cell -->
   <!-- scrap provides <table> context -->
   <xsl:template match="bnf">
-    <tbody xmlns="http://www.w3.org/1999/xhtml">
+    <tbody>
       <tr>
         <td>
           <xsl:if test="@diff and $show.diff.markup != 0">
@@ -389,9 +402,8 @@
        notes) -->
   <xsl:template match="body">
     <xsl:if test="$toc.level &gt; 0">
-      <div xmlns="http://www.w3.org/1999/xhtml" class="toc">
-        <xsl:text>
-</xsl:text>
+      <div class="toc">
+        <xsl:text>&#10;</xsl:text>
         <h2>
           <xsl:call-template name="anchor">
             <xsl:with-param name="conditional" select="0"/>
@@ -403,8 +415,7 @@
           <xsl:apply-templates select="div1" mode="toc"/>
         </p>
         <xsl:if test="../back">
-          <xsl:text>
-</xsl:text>
+          <xsl:text>&#10;</xsl:text>
           <h3>
             <xsl:call-template name="anchor">
               <xsl:with-param name="conditional" select="0"/>
@@ -413,7 +424,7 @@
 
             <xsl:text>Appendi</xsl:text>
             <xsl:choose>
-              <xsl:when test="count(../back/div1 | ../back/inform-div1) &gt; 1">
+              <xsl:when test="count(../back/div1 | ../back/inform-div1) > 1">
                 <xsl:text>ces</xsl:text>
               </xsl:when>
               <xsl:otherwise>
@@ -422,7 +433,8 @@
             </xsl:choose>
           </h3>
           <p class="toc">
-            <xsl:apply-templates mode="toc" select="../back/div1 | ../back/inform-div1"/>
+            <xsl:apply-templates mode="toc"
+                                 select="../back/div1 | ../back/inform-div1"/>
             <xsl:call-template name="autogenerated-appendices-toc"/>
           </p>
         </xsl:if>
@@ -434,9 +446,9 @@
           </p>
         </xsl:if>
       </div>
-      <hr xmlns="http://www.w3.org/1999/xhtml"/>
+      <hr/>
     </xsl:if>
-    <div xmlns="http://www.w3.org/1999/xhtml" class="body">
+    <div class="body">
       <xsl:apply-templates/>
     </div>
   </xsl:template>
@@ -457,7 +469,7 @@
   <!-- code: generic computer code -->
   <!-- output as HTML <code> for monospaced formatting -->
   <xsl:template match="code">
-    <code xmlns="http://www.w3.org/1999/xhtml"><xsl:apply-templates/></code>
+    <code><xsl:apply-templates/></code>
   </xsl:template>
 
   <!-- col: see table -->
@@ -469,7 +481,7 @@
   <xsl:template match="com">
     <xsl:choose>
       <xsl:when test="preceding-sibling::*[1][name()='rhs']">
-        <td xmlns="http://www.w3.org/1999/xhtml">
+        <td>
           <xsl:if test="ancestor-or-self::*/@diff and $show.diff.markup != 0">
             <xsl:attribute name="class">
               <xsl:text>diff-</xsl:text>
@@ -484,7 +496,7 @@
         </td>
       </xsl:when>
       <xsl:otherwise>
-        <tr xmlns="http://www.w3.org/1999/xhtml" valign="baseline">
+        <tr valign="baseline">
           <td/><td/><td/><td/>
           <td>
             <xsl:if test="ancestor-or-self::*/@diff and $show.diff.markup != 0">
@@ -508,7 +520,7 @@
        have arbitrary text and com mixed in, I don't feel like
        spending enough time to figure out how -->
   <xsl:template match="rhs/com">
-    <i xmlns="http://www.w3.org/1999/xhtml">
+    <i>
       <xsl:text>/* </xsl:text>
       <xsl:apply-templates/>
       <xsl:text> */</xsl:text>
@@ -526,7 +538,7 @@
   <xsl:template match="constraint">
     <xsl:choose>
       <xsl:when test="preceding-sibling::*[1][name()='rhs']">
-        <td xmlns="http://www.w3.org/1999/xhtml">
+        <td>
           <xsl:if test="@diff and $show.diff.markup != 0">
             <xsl:attribute name="class">
               <xsl:text>diff-</xsl:text>
@@ -546,7 +558,7 @@
         </td>
       </xsl:when>
       <xsl:otherwise>
-        <tr xmlns="http://www.w3.org/1999/xhtml" valign="baseline">
+        <tr valign="baseline">
           <td/><td/><td/><td/>
           <td>
             <xsl:if test="@diff and $show.diff.markup != 0">
@@ -574,7 +586,7 @@
   <!-- constraintnote: note constraining a formal production -->
   <!-- see also constraintnote/head -->
   <xsl:template match="constraintnote">
-    <div xmlns="http://www.w3.org/1999/xhtml" class="constraint">
+    <div class="constraint">
       <xsl:apply-templates/>
     </div>
   </xsl:template>
@@ -592,7 +604,7 @@
   <!-- def: glossary definition -->
   <!-- already in <dl> context from glist -->
   <xsl:template match="def">
-    <dd xmlns="http://www.w3.org/1999/xhtml">
+    <dd>
       <xsl:apply-templates/>
     </dd>
   </xsl:template>
@@ -607,31 +619,31 @@
   <!-- make an HTML div -->
   <!-- see also div[n]/head -->
   <xsl:template match="div1">
-    <div xmlns="http://www.w3.org/1999/xhtml" class="div1">
+    <div class="div1">
       <xsl:apply-templates/>
     </div>
   </xsl:template>
 
   <xsl:template match="div2">
-    <div xmlns="http://www.w3.org/1999/xhtml" class="div2">
+    <div class="div2">
       <xsl:apply-templates/>
     </div>
   </xsl:template>
 
   <xsl:template match="div3">
-    <div xmlns="http://www.w3.org/1999/xhtml" class="div3">
+    <div class="div3">
       <xsl:apply-templates/>
     </div>
   </xsl:template>
 
   <xsl:template match="div4">
-    <div xmlns="http://www.w3.org/1999/xhtml" class="div4">
+    <div class="div4">
       <xsl:apply-templates/>
     </div>
   </xsl:template>
 
   <xsl:template match="div5">
-    <div xmlns="http://www.w3.org/1999/xhtml" class="div5">
+    <div class="div5">
       <xsl:apply-templates/>
     </div>
   </xsl:template>
@@ -639,7 +651,7 @@
   <!-- ednote: editors' note -->
   <xsl:template match="ednote">
     <xsl:if test="$show.ednotes != 0">
-      <table xmlns="http://www.w3.org/1999/xhtml" border="1">
+      <table border="1">
         <xsl:attribute name="summary">
           <xsl:text>Editorial note</xsl:text>
           <xsl:if test="name">
@@ -662,7 +674,7 @@
               <xsl:when test="date">
                 <xsl:apply-templates select="date"/>
               </xsl:when>
-              <xsl:otherwise> </xsl:otherwise>
+              <xsl:otherwise>&#160;</xsl:otherwise>
             </xsl:choose>
           </td>
         </tr>
@@ -691,14 +703,14 @@
   <!-- Chris's personal preference is to put pointy-brackets around
        this, but he seems to be in the minority -->
   <xsl:template match="el">
-    <code xmlns="http://www.w3.org/1999/xhtml"><xsl:apply-templates/></code>
+    <code><xsl:apply-templates/></code>
   </xsl:template>
 
   <!-- email: an email address for an editor -->
   <!-- only occurs in author -->
   <xsl:template match="email">
     <xsl:text> </xsl:text>
-    <a xmlns="http://www.w3.org/1999/xhtml" href="{@href}">
+    <a href="{@href}">
       <xsl:text>&lt;</xsl:text>
       <xsl:apply-templates/>
       <xsl:text>&gt;</xsl:text>
@@ -710,12 +722,12 @@
   <!-- the role attribute could be used for multiple kinds of
        emphasis, but that would not be kind -->
   <xsl:template match="emph">
-    <em xmlns="http://www.w3.org/1999/xhtml"><xsl:apply-templates/></em>
+    <em><xsl:apply-templates/></em>
   </xsl:template>
 
   <!-- rfc2119: identifies RFC 2119 keywords -->
   <xsl:template match="rfc2119">
-    <strong xmlns="http://www.w3.org/1999/xhtml"><xsl:apply-templates/></strong>
+    <strong><xsl:apply-templates/></strong>
   </xsl:template>
 
   <!-- enum: -->
@@ -734,17 +746,16 @@
         <xsl:otherwise>example</xsl:otherwise>
       </xsl:choose>
     </xsl:variable>
-    <div xmlns="http://www.w3.org/1999/xhtml" class="{$class}">
+    <div class="{$class}">
       <xsl:apply-templates/>
     </div>
   </xsl:template>
 
   <xsl:template match="example/head">
-    <xsl:text>
-</xsl:text>
+    <xsl:text>&#10;</xsl:text>
     <xsl:choose>
       <xsl:when test="$tabular.examples = 0">
-        <div xmlns="http://www.w3.org/1999/xhtml" class="exampleHeader">
+        <div class="exampleHeader">
           <xsl:call-template name="anchor">
             <xsl:with-param name="node" select=".."/>
             <xsl:with-param name="conditional" select="0"/>
@@ -754,7 +765,7 @@
         </div>
       </xsl:when>
       <xsl:otherwise>
-        <h5 xmlns="http://www.w3.org/1999/xhtml">
+        <h5>
           <xsl:call-template name="anchor">
             <xsl:with-param name="node" select=".."/>
             <xsl:with-param name="conditional" select="0"/>
@@ -772,7 +783,7 @@
   <xsl:template match="eg">
     <xsl:variable name="content">
       <xsl:call-template name="anchor"/>
-      <pre xmlns="http://www.w3.org/1999/xhtml">
+      <pre>
         <xsl:if test="@diff and $show.diff.markup != 0">
           <xsl:attribute name="class">
             <xsl:text>diff-</xsl:text>
@@ -784,12 +795,14 @@
     </xsl:variable>
     <xsl:choose>
       <xsl:when test="$tabular.examples = 0">
-        <div xmlns="http://www.w3.org/1999/xhtml" class="exampleInner">
+        <div class="exampleInner">
           <xsl:copy-of select="$content"/>
         </div>
       </xsl:when>
       <xsl:otherwise>
-        <table xmlns="http://www.w3.org/1999/xhtml" class="eg" cellpadding="5" border="1" bgcolor="#99ffff" width="100%" summary="Example">
+        <table class="eg" cellpadding="5" border="1"
+               bgcolor="#99ffff" width="100%"
+               summary="Example">
           <tr>
             <td>
               <xsl:copy-of select="$content"/>
@@ -815,9 +828,10 @@
         </xsl:otherwise>
       </xsl:choose>
     </xsl:variable>
-    <sup xmlns="http://www.w3.org/1999/xhtml">
+    <sup>
       <xsl:text>[</xsl:text>
-      <a name="FN-ANCH-{$this-note-id}" id="FN-ANCH-{$this-note-id}" href="#{$this-note-id}">
+      <a id="FN-ANCH-{$this-note-id}"
+         href="#{$this-note-id}">
         <xsl:apply-templates select="." mode="number-simple"/>
       </a>
       <xsl:text>]</xsl:text>
@@ -827,7 +841,7 @@
   <!-- front: front matter for the spec -->
   <!-- make a div for cleanliness -->
   <xsl:template match="front">
-    <div xmlns="http://www.w3.org/1999/xhtml" class="front">
+    <div class="front">
       <xsl:apply-templates/>
     </div>
   </xsl:template>
@@ -835,7 +849,7 @@
   <!-- function: name of a function -->
   <!-- format as HTML <code> for monospaced presentation -->
   <xsl:template match="function">
-    <code xmlns="http://www.w3.org/1999/xhtml"><xsl:apply-templates/></code>
+    <code><xsl:apply-templates/></code>
   </xsl:template>
 
   <!-- gitem: glossary list entry -->
@@ -850,7 +864,7 @@
     <xsl:if test="$validity.hacks = 1 and local-name(..) = 'p'">
       <xsl:text disable-output-escaping="yes">&lt;/p&gt;</xsl:text>
     </xsl:if>
-    <dl xmlns="http://www.w3.org/1999/xhtml">
+    <dl>
       <xsl:apply-templates/>
     </dl>
     <xsl:if test="$validity.hacks = 1 and local-name(..) = 'p'">
@@ -861,7 +875,7 @@
   <!-- graphic: external illustration -->
   <!-- reference external graphic file with alt text -->
   <xsl:template match="graphic">
-    <img xmlns="http://www.w3.org/1999/xhtml" src="{@source}">
+    <img src="{@source}">
       <xsl:if test="@alt">
         <xsl:attribute name="alt">
           <xsl:value-of select="@alt"/>
@@ -878,18 +892,17 @@
   <!-- constraintnotes have different types, but they're
        non-enumerated; nothing is done with them right now -->
   <xsl:template match="constraintnote/head">
-    <p xmlns="http://www.w3.org/1999/xhtml" class="prefix">
+    <p class="prefix">
       <xsl:if test="../@id">
-        <a name="{../@id}" id="{../@id}"/>
+        <a id="{../@id}"/>
       </xsl:if>
       <b><xsl:text>Constraint: </xsl:text><xsl:apply-templates/></b>
     </p>
   </xsl:template>
 
   <xsl:template match="div1/head">
-    <xsl:text>
-</xsl:text>
-    <h2 xmlns="http://www.w3.org/1999/xhtml">
+    <xsl:text>&#10;</xsl:text>
+    <h2>
       <xsl:call-template name="anchor">
         <xsl:with-param name="conditional" select="0"/>
         <xsl:with-param name="node" select=".."/>
@@ -900,9 +913,8 @@
   </xsl:template>
 
   <xsl:template match="div2/head">
-    <xsl:text>
-</xsl:text>
-    <h3 xmlns="http://www.w3.org/1999/xhtml">
+    <xsl:text>&#10;</xsl:text>
+    <h3>
       <xsl:call-template name="anchor">
         <xsl:with-param name="conditional" select="0"/>
         <xsl:with-param name="node" select=".."/>
@@ -913,9 +925,8 @@
   </xsl:template>
 
   <xsl:template match="div3/head">
-    <xsl:text>
-</xsl:text>
-    <h4 xmlns="http://www.w3.org/1999/xhtml">
+    <xsl:text>&#10;</xsl:text>
+    <h4>
       <xsl:call-template name="anchor">
         <xsl:with-param name="conditional" select="0"/>
         <xsl:with-param name="node" select=".."/>
@@ -926,9 +937,8 @@
   </xsl:template>
 
   <xsl:template match="div4/head">
-    <xsl:text>
-</xsl:text>
-    <h5 xmlns="http://www.w3.org/1999/xhtml">
+    <xsl:text>&#10;</xsl:text>
+    <h5>
       <xsl:call-template name="anchor">
         <xsl:with-param name="conditional" select="0"/>
         <xsl:with-param name="node" select=".."/>
@@ -939,9 +949,8 @@
   </xsl:template>
 
   <xsl:template match="div5/head">
-    <xsl:text>
-</xsl:text>
-    <h6 xmlns="http://www.w3.org/1999/xhtml">
+    <xsl:text>&#10;</xsl:text>
+    <h6>
       <xsl:call-template name="anchor">
         <xsl:with-param name="conditional" select="0"/>
         <xsl:with-param name="node" select=".."/>
@@ -952,9 +961,8 @@
   </xsl:template>
 
   <xsl:template match="inform-div1/head">
-    <xsl:text>
-</xsl:text>
-    <h2 xmlns="http://www.w3.org/1999/xhtml">
+    <xsl:text>&#10;</xsl:text>
+    <h2>
       <xsl:call-template name="anchor">
         <xsl:with-param name="conditional" select="0"/>
         <xsl:with-param name="node" select=".."/>
@@ -966,15 +974,14 @@
   </xsl:template>
 
   <xsl:template match="issue/head">
-    <p xmlns="http://www.w3.org/1999/xhtml" class="prefix">
+    <p class="prefix">
       <b><xsl:apply-templates/></b>
     </p>
   </xsl:template>
 
   <xsl:template match="scrap/head">
-    <xsl:text>
-</xsl:text>
-    <h5 xmlns="http://www.w3.org/1999/xhtml">
+    <xsl:text>&#10;</xsl:text>
+    <h5>
       <xsl:call-template name="anchor">
         <xsl:with-param name="node" select=".."/>
         <xsl:with-param name="conditional" select="0"/>
@@ -985,18 +992,18 @@
   </xsl:template>
 
   <xsl:template match="vcnote/head">
-    <p xmlns="http://www.w3.org/1999/xhtml" class="prefix">
+    <p class="prefix">
       <xsl:if test="../@id">
-        <a name="{../@id}" id="{../@id}"/>
+        <a id="{../@id}"/>
       </xsl:if>
       <b><xsl:text>Validity constraint: </xsl:text><xsl:apply-templates/></b>
     </p>
   </xsl:template>
 
   <xsl:template match="wfcnote/head">
-    <p xmlns="http://www.w3.org/1999/xhtml" class="prefix">
+    <p class="prefix">
       <xsl:if test="../@id">
-        <a name="{../@id}" id="{../@id}"/>
+        <a id="{../@id}"/>
       </xsl:if>
       <b><xsl:text>Well-formedness constraint: </xsl:text><xsl:apply-templates/></b>
     </p>
@@ -1005,28 +1012,30 @@
   <!-- header: metadata about the spec -->
   <!-- pull out information into standard W3C layout -->
   <xsl:template match="header">
-    <div xmlns="http://www.w3.org/1999/xhtml" class="head">
+    <div class="head">
       <xsl:if test="not(/spec/@role='editors-copy')">
         <p>
           <a href="http://www.w3.org/">
-            <img src="http://www.w3.org/Icons/w3c_home" alt="W3C" height="48" width="72"/>
+            <img src="http://www.w3.org/Icons/w3c_home"
+              alt="W3C" height="48" width="72"/>
           </a>
 	  <xsl:choose>
 	    <xsl:when test="/spec/@w3c-doctype='memsub'">
-	      <a href="http://www.w3.org/Submission/">
-		<img alt="Member Submission" src="http://www.w3.org/Icons/member_subm"/>
+	      <a href='http://www.w3.org/Submission/'>
+		<img alt='Member Submission'
+		     src='http://www.w3.org/Icons/member_subm'/>
 	      </a>
 	    </xsl:when>
 	    <xsl:when test="/spec/@w3c-doctype='teamsub'">
-	      <a href="http://www.w3.org/2003/06/TeamSubmission">
-		<img alt="Team Submission" src="http://www.w3.org/Icons/team_subm"/>
+	      <a href='http://www.w3.org/2003/06/TeamSubmission'>
+		<img alt='Team Submission'
+		     src='http://www.w3.org/Icons/team_subm'/>
 	      </a>
 	    </xsl:when>
 	  </xsl:choose>
         </p>
       </xsl:if>
-      <xsl:text>
-</xsl:text>
+      <xsl:text>&#10;</xsl:text>
       <h1>
         <xsl:call-template name="anchor">
           <xsl:with-param name="node" select="title[1]"/>
@@ -1041,8 +1050,7 @@
         </xsl:if>
       </h1>
       <xsl:if test="subtitle">
-        <xsl:text>
-</xsl:text>
+        <xsl:text>&#10;</xsl:text>
         <h2>
           <xsl:call-template name="anchor">
             <xsl:with-param name="node" select="subtitle[1]"/>
@@ -1052,8 +1060,7 @@
           <xsl:apply-templates select="subtitle"/>
         </h2>
       </xsl:if>
-      <xsl:text>
-</xsl:text>
+      <xsl:text>&#10;</xsl:text>
       <h2>
 	<xsl:call-template name="anchor">
 	  <xsl:with-param name="node" select="w3c-doctype[1]"/>
@@ -1100,13 +1107,13 @@
             <a href="http://www.w3.org/Consortium/Legal/ipr-notice#Copyright">
               <xsl:text>Copyright</xsl:text>
             </a>
-            <xsl:text> © </xsl:text>
+            <xsl:text>&#xa0;&#xa9;&#xa0;</xsl:text>
             <xsl:apply-templates select="pubdate/year"/>
-            <xsl:text> </xsl:text>
+            <xsl:text>&#xa0;</xsl:text>
             <a href="http://www.w3.org/">
               <acronym title="World Wide Web Consortium">W3C</acronym>
             </a>
-            <sup>®</sup>
+            <sup>&#xae;</sup>
             <xsl:text> (</xsl:text>
             <a href="http://www.csail.mit.edu/">
               <acronym title="Massachusetts Institute of Technology">MIT</acronym>
@@ -1118,7 +1125,7 @@
             <xsl:text>, </xsl:text>
             <a href="http://www.keio.ac.jp/">Keio</a>
             <xsl:text>, </xsl:text>
-	    <a href="http://ev.buaa.edu.cn/">Beihang</a>
+            <a href="http://ev.buaa.edu.cn/">Beihang</a>
             <xsl:text>), All Rights Reserved. W3C </xsl:text>
             <a href="http://www.w3.org/Consortium/Legal/ipr-notice#Legal_Disclaimer">liability</a>
             <xsl:text>, </xsl:text>
@@ -1130,7 +1137,7 @@
         </xsl:otherwise>
       </xsl:choose>
     </div>
-    <hr xmlns="http://www.w3.org/1999/xhtml"/>
+    <hr/>
     <xsl:apply-templates select="notice"/>
     <xsl:apply-templates select="abstract"/>
     <xsl:apply-templates select="status"/>
@@ -1146,7 +1153,7 @@
   </xsl:template>
 
   <xsl:template match="copyright/p">
-    <p xmlns="http://www.w3.org/1999/xhtml" class="copyright">
+    <p class="copyright">
       <xsl:apply-templates/>
     </p>
   </xsl:template>
@@ -1154,7 +1161,7 @@
   <!-- inform-div1: non-normative back matter top-level division -->
   <!-- treat like div1 except add "(Non-Normative)" to title -->
   <xsl:template match="inform-div1">
-    <div xmlns="http://www.w3.org/1999/xhtml" class="div1">
+    <div class="div1">
       <xsl:apply-templates/>
     </div>
   </xsl:template>
@@ -1168,10 +1175,10 @@
        element; this should probably be cleaned up to only use the
        head if it's present -->
   <xsl:template match="issue">
-    <div xmlns="http://www.w3.org/1999/xhtml" class="issue">
+    <div class="issue">
       <p class="prefix">
         <xsl:if test="@id">
-          <a name="{@id}" id="{@id}"/>
+          <a id="{@id}"/>
         </xsl:if>
         <b>
           <xsl:text>Issue (</xsl:text>
@@ -1194,7 +1201,7 @@
 
   <!-- item: generic list item -->
   <xsl:template match="item">
-    <li xmlns="http://www.w3.org/1999/xhtml">
+    <li>
       <xsl:if test="@id">
 	<xsl:attribute name="id">
 	  <xsl:value-of select="@id"/>
@@ -1207,13 +1214,13 @@
   <!-- kw: keyword -->
   <!-- make it bold -->
   <xsl:template match="kw">
-    <b xmlns="http://www.w3.org/1999/xhtml"><xsl:apply-templates/></b>
+    <b><xsl:apply-templates/></b>
   </xsl:template>
 
   <!-- label: term for defintion in glossary entry -->
   <!-- already in <dl> context from glist -->
   <xsl:template match="label">
-    <dt xmlns="http://www.w3.org/1999/xhtml" class="label">
+    <dt class="label">
       <xsl:call-template name="anchor">
         <xsl:with-param name="node" select=".."/>
       </xsl:call-template>
@@ -1237,10 +1244,10 @@
     <xsl:choose>
       <xsl:when test="count(loc) &gt; 1">
 	<xsl:for-each select="loc">
-	  <dt xmlns="http://www.w3.org/1999/xhtml">
+	  <dt>
 	    <xsl:apply-templates select="node()"/>
 	  </dt>
-	  <dd xmlns="http://www.w3.org/1999/xhtml">
+	  <dd>
 	    <a href="{@href}">
 	      <xsl:value-of select="@href"/>
 	    </a>
@@ -1248,8 +1255,8 @@
 	</xsl:for-each>
       </xsl:when>
       <xsl:otherwise>
-	<dt xmlns="http://www.w3.org/1999/xhtml">Latest version:</dt>
-	<dd xmlns="http://www.w3.org/1999/xhtml">
+	<dt>Latest version:</dt>
+	<dd>
 	  <xsl:apply-templates/>
 	</dd>
       </xsl:otherwise>
@@ -1260,7 +1267,7 @@
   <!-- make a table row with the lhs and the corresponding other
        pieces in this crazy mixed-up content model -->
   <xsl:template match="lhs">
-    <tr xmlns="http://www.w3.org/1999/xhtml" valign="baseline">
+    <tr valign="baseline">
       <td>
         <xsl:if test="ancestor-or-self::*/@diff and $show.diff.markup != 0">
           <xsl:attribute name="class">
@@ -1269,7 +1276,7 @@
           </xsl:attribute>
         </xsl:if>
         <xsl:if test="../@id">
-          <a name="{../@id}" id="{../@id}"/>
+          <a id="{../@id}"/>
         </xsl:if>
         <xsl:apply-templates select="ancestor::prod" mode="number"/>
 <!--
@@ -1278,7 +1285,7 @@
           <xsl:number count="prod" level="any" from="spec"
             format="[1]"/>
   -->
-        <xsl:text>   </xsl:text>
+        <xsl:text>&#xa0;&#xa0;&#xa0;</xsl:text>
       </td>
       <td>
         <xsl:if test="ancestor-or-self::*/@diff and $show.diff.markup != 0">
@@ -1296,9 +1303,10 @@
             <xsl:value-of select="ancestor-or-self::*/@diff"/>
           </xsl:attribute>
         </xsl:if>
-        <xsl:text>   ::=   </xsl:text>
+        <xsl:text>&#xa0;&#xa0;&#xa0;::=&#xa0;&#xa0;&#xa0;</xsl:text>
       </td>
-      <xsl:apply-templates select="following-sibling::*[1][name()='rhs']"/>
+      <xsl:apply-templates
+        select="following-sibling::*[1][name()='rhs']"/>
     </tr>
   </xsl:template>
 
@@ -1315,7 +1323,7 @@
       </xsl:if>
     </xsl:if>
 
-    <a xmlns="http://www.w3.org/1999/xhtml" href="{@href}">
+    <a href="{@href}">
       <xsl:choose>
         <xsl:when test="count(child::node())=0">
           <xsl:value-of select="@href"/>
@@ -1330,7 +1338,7 @@
   <!-- member: member of an organization -->
   <!-- appears only in orglist, which creates <ul> context -->
   <xsl:template match="member">
-    <li xmlns="http://www.w3.org/1999/xhtml">
+    <li>
       <xsl:apply-templates/>
     </li>
   </xsl:template>
@@ -1356,7 +1364,7 @@
 
   <!-- note: a note about the spec -->
   <xsl:template match="note">
-    <div xmlns="http://www.w3.org/1999/xhtml" class="note">
+    <div class="note">
       <p class="prefix">
         <b>Note:</b>
       </p>
@@ -1367,7 +1375,7 @@
   <!-- notice: a front-matter advisory about the spec's status -->
   <!-- make sure people notice it -->
   <xsl:template match="notice">
-    <div xmlns="http://www.w3.org/1999/xhtml" class="notice">
+    <div class="notice">
       <p class="prefix">
         <b>NOTICE:</b>
       </p>
@@ -1378,7 +1386,7 @@
   <!-- nt: production non-terminal -->
   <!-- make a link to the non-terminal's definition -->
   <xsl:template match="nt">
-    <a xmlns="http://www.w3.org/1999/xhtml">
+    <a>
       <xsl:attribute name="href">
         <xsl:call-template name="href.target">
           <xsl:with-param name="target" select="key('ids', @def)"/>
@@ -1408,21 +1416,21 @@
       <xsl:call-template name="list.numeration"/>
     </xsl:variable>
 
-    <ol xmlns="http://www.w3.org/1999/xhtml" class="enum{$numeration}">
+    <ol class="enum{$numeration}">
       <xsl:apply-templates/>
     </ol>
   </xsl:template>
 
   <!-- orglist: a list of an organization's members -->
   <xsl:template match="orglist">
-    <ul xmlns="http://www.w3.org/1999/xhtml">
+    <ul>
       <xsl:apply-templates/>
     </ul>
   </xsl:template>
 
   <!-- p: a standard paragraph -->
   <xsl:template match="p">
-    <p xmlns="http://www.w3.org/1999/xhtml">
+    <p>
       <xsl:if test="@id">
         <xsl:attribute name="id">
           <xsl:value-of select="@id"/>
@@ -1447,7 +1455,7 @@
   <!-- role attributes may be used to request different formatting,
        which isn't currently handled -->
   <xsl:template match="phrase">
-    <span xmlns="http://www.w3.org/1999/xhtml">
+    <span>
       <xsl:if test="@role">
         <xsl:attribute name="class">
           <xsl:value-of select="@role"/>
@@ -1460,12 +1468,12 @@
   <!-- prevlocs: previous locations for this spec -->
   <!-- called in a <dl> context from header -->
   <xsl:template match="prevlocs">
-    <dt xmlns="http://www.w3.org/1999/xhtml">
+    <dt>
       <xsl:text>Previous version</xsl:text>
       <xsl:if test="count(loc) &gt; 1">s</xsl:if>
       <xsl:text>:</xsl:text>
     </dt>
-    <dd xmlns="http://www.w3.org/1999/xhtml">
+    <dd>
       <xsl:apply-templates/>
     </dd>
   </xsl:template>
@@ -1477,19 +1485,31 @@
   <!-- process the first child in each row, and it will process the
        others -->
   <xsl:template match="prod">
-    <tbody xmlns="http://www.w3.org/1999/xhtml">
-      <xsl:apply-templates select="lhs |                 rhs[preceding-sibling::*[1][name()!='lhs']] |                 com[preceding-sibling::*[1][name()!='rhs']] |                 constraint[preceding-sibling::*[1][name()!='rhs']] |                 vc[preceding-sibling::*[1][name()!='rhs']] |                 wfc[preceding-sibling::*[1][name()!='rhs']]"/>
+    <tbody>
+      <xsl:apply-templates
+        select="lhs |
+                rhs[preceding-sibling::*[1][name()!='lhs']] |
+                com[preceding-sibling::*[1][name()!='rhs']] |
+                constraint[preceding-sibling::*[1][name()!='rhs']] |
+                vc[preceding-sibling::*[1][name()!='rhs']] |
+                wfc[preceding-sibling::*[1][name()!='rhs']]"/>
     </tbody>
   </xsl:template>
 
   <xsl:template match="prodgroup/prod">
-    <xsl:apply-templates select="lhs |               rhs[preceding-sibling::*[1][name()!='lhs']] |               com[preceding-sibling::*[1][name()!='rhs']] |               constraint[preceding-sibling::*[1][name()!='rhs']] |               vc[preceding-sibling::*[1][name()!='rhs']] |               wfc[preceding-sibling::*[1][name()!='rhs']]"/>
+    <xsl:apply-templates
+      select="lhs |
+              rhs[preceding-sibling::*[1][name()!='lhs']] |
+              com[preceding-sibling::*[1][name()!='rhs']] |
+              constraint[preceding-sibling::*[1][name()!='rhs']] |
+              vc[preceding-sibling::*[1][name()!='rhs']] |
+              wfc[preceding-sibling::*[1][name()!='rhs']]"/>
   </xsl:template>
 
   <!-- prodgroup: group of formal productions -->
   <!-- create one <tbody> for each group -->
   <xsl:template match="prodgroup">
-    <tbody xmlns="http://www.w3.org/1999/xhtml">
+    <tbody>
       <xsl:apply-templates/>
     </tbody>
   </xsl:template>
@@ -1499,14 +1519,14 @@
        <tbody> or a number, plus links the lhs to the original
        production -->
   <xsl:template match="prodrecap">
-    <tbody xmlns="http://www.w3.org/1999/xhtml">
+    <tbody>
       <xsl:apply-templates select="key('ids', @ref)" mode="ref"/>
     </tbody>
   </xsl:template>
 
   <xsl:template match="processing-instruction('specprod')">
     <xsl:if test="contains(., 'production-recap')"/>
-    <table xmlns="http://www.w3.org/1999/xhtml" class="scrap" summary="Scrap">
+    <table class="scrap" summary="Scrap">
       <tbody>
         <xsl:apply-templates select="//prod" mode="ref"/>
       </tbody>
@@ -1516,7 +1536,7 @@
   <!-- proto: function prototype -->
   <!-- type and name of the function, with arguments in parens -->
   <xsl:template match="proto">
-    <p xmlns="http://www.w3.org/1999/xhtml">
+    <p>
       <em><xsl:value-of select="@return-type"/></em>
       <xsl:text> </xsl:text>
       <b><xsl:value-of select="@name"/></b>
@@ -1532,14 +1552,14 @@
   <!-- publoc: location of current version of spec -->
   <!-- called from header in <dl> context -->
   <xsl:template match="publoc">
-    <dt xmlns="http://www.w3.org/1999/xhtml">This version:</dt>
-    <dd xmlns="http://www.w3.org/1999/xhtml">
+    <dt>This version:</dt>
+    <dd>
       <xsl:apply-templates/>
     </dd>
   </xsl:template>
 
   <xsl:template match="altlocs">
-    <p xmlns="http://www.w3.org/1999/xhtml">
+    <p>
       <xsl:text>This document is also available </xsl:text>
       <xsl:text>in these non-normative formats: </xsl:text>
       <xsl:for-each select="loc">
@@ -1551,7 +1571,7 @@
             <xsl:text> </xsl:text>
           </xsl:if>
         </xsl:if>
-        <xsl:if test="position() = last() and position() &gt; 1">and </xsl:if>
+        <xsl:if test="position() = last() and position() &gt; 1">and&#160;</xsl:if>
         <xsl:apply-templates select="."/>
       </xsl:for-each>
       <xsl:text>.</xsl:text>
@@ -1559,7 +1579,7 @@
   </xsl:template>
 
   <xsl:template match="errataloc">
-    <p xmlns="http://www.w3.org/1999/xhtml">
+    <p>
       <xsl:text>Please refer to the </xsl:text>
       <a href="{@href}">errata</a>
       <xsl:text> for this document, which may
@@ -1568,7 +1588,7 @@
   </xsl:template>
 
   <xsl:template match="preverrataloc">
-    <p xmlns="http://www.w3.org/1999/xhtml">
+    <p>
       <xsl:text>The </xsl:text>
       <a href="{@href}">previous errata</a>
       <xsl:text> for this document, are also available.</xsl:text>
@@ -1576,7 +1596,7 @@
   </xsl:template>
 
   <xsl:template match="translationloc">
-    <p xmlns="http://www.w3.org/1999/xhtml">See also <a href="{@href}"><strong>translations</strong></a>.</p>
+    <p>See also <a href="{@href}"><strong>translations</strong></a>.</p>
   </xsl:template>
 
   <!-- pubstmt: statement of publication -->
@@ -1599,7 +1619,7 @@
 
   <!-- resolution: resolution of an issue -->
   <xsl:template match="resolution">
-    <p xmlns="http://www.w3.org/1999/xhtml" class="prefix">
+    <p class="prefix">
       <b>
         <xsl:if test="@role='partial'">Partial </xsl:if>
         <xsl:text>Resolution:</xsl:text>
@@ -1620,7 +1640,7 @@
   <xsl:template match="rhs">
     <xsl:choose>
       <xsl:when test="preceding-sibling::*[1][name()='lhs']">
-        <td xmlns="http://www.w3.org/1999/xhtml">
+        <td>
           <xsl:if test="ancestor-or-self::*/@diff and $show.diff.markup != 0">
             <xsl:attribute name="class">
               <xsl:text>diff-</xsl:text>
@@ -1629,10 +1649,14 @@
           </xsl:if>
           <code><xsl:apply-templates/></code>
         </td>
-        <xsl:apply-templates select="following-sibling::*[1][name()='com' or                                           name()='constraint' or                                           name()='vc' or                                           name()='wfc']"/>
+        <xsl:apply-templates
+          select="following-sibling::*[1][name()='com' or
+                                          name()='constraint' or
+                                          name()='vc' or
+                                          name()='wfc']"/>
       </xsl:when>
       <xsl:otherwise>
-        <tr xmlns="http://www.w3.org/1999/xhtml" valign="baseline">
+        <tr valign="baseline">
           <td/><td/><td/>
           <td>
             <xsl:if test="ancestor-or-self::*/@diff and $show.diff.markup != 0">
@@ -1643,7 +1667,11 @@
             </xsl:if>
             <code><xsl:apply-templates/></code>
           </td>
-          <xsl:apply-templates select="following-sibling::*[1][name()='com' or                                             name()='constraint' or                                             name()='vc' or                                             name()='wfc']"/>
+          <xsl:apply-templates
+            select="following-sibling::*[1][name()='com' or
+                                            name()='constraint' or
+                                            name()='vc' or
+                                            name()='wfc']"/>
         </tr>
       </xsl:otherwise>
     </xsl:choose>
@@ -1652,7 +1680,7 @@
   <!-- role: part played by a member of an organization -->
   <xsl:template match="role">
     <xsl:text> (</xsl:text>
-    <i xmlns="http://www.w3.org/1999/xhtml"><xsl:apply-templates/></i>
+    <i><xsl:apply-templates/></i>
     <xsl:text>) </xsl:text>
   </xsl:template>
 
@@ -1660,7 +1688,7 @@
   <!-- set up a <table> and handle children -->
   <xsl:template match="scrap">
     <xsl:apply-templates select="head"/>
-    <table xmlns="http://www.w3.org/1999/xhtml" class="scrap" summary="Scrap">
+    <table class="scrap" summary="Scrap">
       <xsl:apply-templates select="bnf | prod | prodgroup"/>
     </table>
   </xsl:template>
@@ -1675,14 +1703,14 @@
   </xsl:template>
 
   <xsl:template match="sitem[position() &gt; 1]" priority="2">
-    <br xmlns="http://www.w3.org/1999/xhtml"/>
+    <br/>
     <xsl:apply-templates/>
   </xsl:template>
 
   <!-- slist: simple list -->
   <!-- using a <blockquote> to indent the list is very wrong, but it works -->
   <xsl:template match="slist">
-    <blockquote xmlns="http://www.w3.org/1999/xhtml">
+    <blockquote>
       <p>
         <xsl:apply-templates/>
       </p>
@@ -1691,7 +1719,7 @@
 
   <!-- source: the source of an issue -->
   <xsl:template match="source">
-    <p xmlns="http://www.w3.org/1999/xhtml">
+    <p>
       <b>Source</b>
       <xsl:text>: </xsl:text>
       <xsl:apply-templates/>
@@ -1703,7 +1731,7 @@
 
   <!-- spec: the specification itself -->
   <xsl:template match="spec">
-    <html xmlns="http://www.w3.org/1999/xhtml">
+    <html>
       <xsl:if test="header/langusage/language">
         <xsl:attribute name="lang">
           <xsl:value-of select="header/langusage/language/@id"/>
@@ -1729,8 +1757,7 @@
         <xsl:if test="//footnote[not(ancestor::table)]">
           <hr/>
           <div class="endnotes">
-            <xsl:text>
-</xsl:text>
+            <xsl:text>&#10;</xsl:text>
             <h3>
               <xsl:call-template name="anchor">
                 <xsl:with-param name="conditional" select="0"/>
@@ -1739,7 +1766,8 @@
               <xsl:text>End Notes</xsl:text>
             </h3>
             <dl>
-              <xsl:apply-templates select="//footnote[not(ancestor::table)]" mode="notes"/>
+              <xsl:apply-templates select="//footnote[not(ancestor::table)]"
+                                   mode="notes"/>
             </dl>
           </div>
         </xsl:if>
@@ -1760,7 +1788,14 @@
 	  <xsl:value-of select="@ref"/>
 	</xsl:message>
       </xsl:when>
-      <xsl:when test="local-name($target)='issue'                       or starts-with(local-name($target), 'div')                       or starts-with(local-name($target), 'inform-div')                       or local-name($target) = 'vcnote'                       or local-name($target) = 'prod'                       or local-name($target) = 'example'                       or local-name($target) = 'label'         or $target/self::item[parent::olist]">
+      <xsl:when test="local-name($target)='issue'
+                      or starts-with(local-name($target), 'div')
+                      or starts-with(local-name($target), 'inform-div')
+                      or local-name($target) = 'vcnote'
+                      or local-name($target) = 'prod'
+                      or local-name($target) = 'example'
+                      or local-name($target) = 'label'
+		      or $target/self::item[parent::olist]">
         <xsl:apply-templates select="$target" mode="specref"/>
       </xsl:when>
       <xsl:otherwise>
@@ -1772,7 +1807,7 @@
           <xsl:text>] </xsl:text>
           <xsl:text> (Contact stylesheet maintainer).</xsl:text>
         </xsl:message>
-        <b xmlns="http://www.w3.org/1999/xhtml">
+        <b>
           <a>
             <xsl:attribute name="href">
               <xsl:call-template name="href.target">
@@ -1789,7 +1824,7 @@
   <xsl:template match="item" mode="specref">
     <xsl:variable name="items" select="ancestor-or-self::item[parent::olist]"/>
 
-    <a xmlns="http://www.w3.org/1999/xhtml">
+    <a>
       <xsl:attribute name="href">
         <xsl:call-template name="href.target"/>
       </xsl:attribute>
@@ -1846,7 +1881,7 @@
 
   <xsl:template match="issue" mode="specref">
     <xsl:text>[</xsl:text>
-    <a xmlns="http://www.w3.org/1999/xhtml">
+    <a>
       <xsl:attribute name="href">
         <xsl:call-template name="href.target"/>
       </xsl:attribute>
@@ -1861,7 +1896,7 @@
   </xsl:template>
 
   <xsl:template match="div1|div2|div3|div4|div5" mode="specref">
-    <a xmlns="http://www.w3.org/1999/xhtml">
+    <a>
       <xsl:attribute name="href">
         <xsl:call-template name="href.target"/>
       </xsl:attribute>
@@ -1873,7 +1908,7 @@
   </xsl:template>
 
   <xsl:template match="inform-div1" mode="specref">
-    <a xmlns="http://www.w3.org/1999/xhtml">
+    <a>
       <xsl:attribute name="href">
         <xsl:call-template name="href.target"/>
       </xsl:attribute>
@@ -1885,7 +1920,7 @@
   </xsl:template>
 
   <xsl:template match="vcnote" mode="specref">
-    <b xmlns="http://www.w3.org/1999/xhtml">
+    <b>
       <xsl:text>[VC: </xsl:text>
       <a>
         <xsl:attribute name="href">
@@ -1898,7 +1933,7 @@
   </xsl:template>
 
   <xsl:template match="prod" mode="specref">
-    <b xmlns="http://www.w3.org/1999/xhtml">
+    <b>
       <xsl:text>[PROD: </xsl:text>
       <a>
         <xsl:attribute name="href">
@@ -1911,7 +1946,7 @@
   </xsl:template>
 
   <xsl:template match="label" mode="specref">
-    <b xmlns="http://www.w3.org/1999/xhtml">
+    <b>
       <xsl:text>[</xsl:text>
       <a>
         <xsl:attribute name="href">
@@ -1934,7 +1969,7 @@
       </xsl:call-template>
     </xsl:variable>
 
-    <a xmlns="http://www.w3.org/1999/xhtml" href="#{$id}">
+    <a href="#{$id}">
       <xsl:text>Example</xsl:text>
     </a>
   </xsl:template>
@@ -1943,9 +1978,8 @@
 
   <!-- status: the status of the spec -->
   <xsl:template match="status">
-    <div xmlns="http://www.w3.org/1999/xhtml">
-      <xsl:text>
-</xsl:text>
+    <div>
+      <xsl:text>&#10;</xsl:text>
       <h2>
         <xsl:call-template name="anchor">
           <xsl:with-param name="conditional" select="0"/>
@@ -1954,7 +1988,7 @@
         <xsl:text>Status of this Document</xsl:text>
       </h2>
       <xsl:if test="/spec/@role='editors-copy'">
-        <p><strong>This document is an editors' copy that has
+        <p><strong>This document is an editor's copy that has
         no official standing.</strong></p>
       </xsl:if>
       <xsl:apply-templates/>
@@ -1966,7 +2000,7 @@
 
   <!-- sub: subscript -->
   <xsl:template match="sub">
-    <sub xmlns="http://www.w3.org/1999/xhtml">
+    <sub>
       <xsl:apply-templates/>
     </sub>
   </xsl:template>
@@ -1979,7 +2013,7 @@
 
   <!-- sup: superscript -->
   <xsl:template match="sup">
-    <sup xmlns="http://www.w3.org/1999/xhtml">
+    <sup>
       <xsl:apply-templates/>
     </sup>
   </xsl:template>
@@ -1987,7 +2021,7 @@
   <!-- table: the HTML table model adopted wholesale; note however that we -->
   <!-- do this such that the XHTML stylesheet will do the right thing. -->
   <xsl:template match="caption|col|colgroup|tfoot|thead|tr|tbody">
-    <xsl:element name="{local-name(.)}" namespace="http://www.w3.org/1999/xhtml">
+    <xsl:element name="{local-name(.)}">
       <xsl:for-each select="@*">
         <!-- Wait: some of these aren't HTML attributes after all... -->
         <xsl:choose>
@@ -2010,7 +2044,7 @@
 
   <!-- td/th are special -->
   <xsl:template match="td|th">
-    <xsl:element name="{local-name(.)}" namespace="http://www.w3.org/1999/xhtml">
+    <xsl:element name="{local-name(.)}">
       <xsl:for-each select="@*">
         <!-- Wait: some of these aren't HTML attributes after all... -->
 	<xsl:choose>
@@ -2034,7 +2068,7 @@
   <!-- but table is special, to handle footnotes -->
   <xsl:template match="table">
     <xsl:call-template name="anchor"/>
-    <table xmlns="http://www.w3.org/1999/xhtml">
+    <table>
       <xsl:for-each select="@*">
         <!-- Wait: some of these aren't HTML attributes after all... -->
         <xsl:choose>
@@ -2067,13 +2101,13 @@
 
   <!-- term: the actual mention of a term within a termdef -->
   <xsl:template match="term">
-    <b xmlns="http://www.w3.org/1999/xhtml"><xsl:apply-templates/></b>
+    <b><xsl:apply-templates/></b>
   </xsl:template>
 
   <!-- termdef: sentence or phrase defining a term -->
   <xsl:template match="termdef">
     <xsl:text>[</xsl:text>
-    <a xmlns="http://www.w3.org/1999/xhtml" name="{@id}" id="{@id}" title="{@term}">
+    <a id="{@id}" title="{@term}">
       <xsl:text>Definition</xsl:text>
     </a>
     <xsl:text>: </xsl:text>
@@ -2083,7 +2117,7 @@
 
   <!-- termref: reference to a defined term -->
   <xsl:template match="termref">
-    <a xmlns="http://www.w3.org/1999/xhtml" title="{key('ids', @def)/@term}">
+    <a title="{key('ids', @def)/@term}">
       <xsl:attribute name="href">
         <xsl:call-template name="href.target">
           <xsl:with-param name="target" select="key('ids', @def)"/>
@@ -2105,21 +2139,21 @@
   <xsl:template match="titleref">
     <xsl:choose>
       <xsl:when test="@href">
-        <a xmlns="http://www.w3.org/1999/xhtml" href="{@href}">
+        <a href="{@href}">
           <cite>
             <xsl:apply-templates/>
           </cite>
         </a>
       </xsl:when>
       <xsl:when test="ancestor::bibl/@href">
-        <a xmlns="http://www.w3.org/1999/xhtml" href="{ancestor::bibl/@href}">
+        <a href="{ancestor::bibl/@href}">
           <cite>
             <xsl:apply-templates/>
           </cite>
         </a>
       </xsl:when>
       <xsl:otherwise>
-        <cite xmlns="http://www.w3.org/1999/xhtml">
+        <cite>
           <xsl:apply-templates/>
         </cite>
       </xsl:otherwise>
@@ -2136,7 +2170,7 @@
 
   <!-- ulist: unordered list -->
   <xsl:template match="ulist">
-    <ul xmlns="http://www.w3.org/1999/xhtml">
+    <ul>
       <xsl:apply-templates/>
     </ul>
   </xsl:template>
@@ -2146,7 +2180,7 @@
 
   <!-- var: a variable -->
   <xsl:template match="var">
-    <var xmlns="http://www.w3.org/1999/xhtml">
+    <var>
       <xsl:apply-templates/>
     </var>
   </xsl:template>
@@ -2155,7 +2189,7 @@
   <xsl:template match="vc">
     <xsl:choose>
       <xsl:when test="preceding-sibling::*[1][name()='rhs']">
-        <td xmlns="http://www.w3.org/1999/xhtml">
+        <td>
           <xsl:if test="@diff and $show.diff.markup != 0">
             <xsl:attribute name="class">
               <xsl:text>diff-</xsl:text>
@@ -2175,7 +2209,7 @@
         </td>
       </xsl:when>
       <xsl:otherwise>
-        <tr xmlns="http://www.w3.org/1999/xhtml" valign="baseline">
+        <tr valign="baseline">
           <td/><td/><td/><td/>
           <td>
             <xsl:if test="@diff and $show.diff.markup != 0">
@@ -2202,7 +2236,7 @@
 
   <!-- vcnote: validity check note after a formal production -->
   <xsl:template match="vcnote">
-    <div xmlns="http://www.w3.org/1999/xhtml" class="constraint">
+    <div class="constraint">
       <xsl:apply-templates/>
     </div>
   </xsl:template>
@@ -2220,7 +2254,7 @@
   <xsl:template match="wfc">
     <xsl:choose>
       <xsl:when test="preceding-sibling::*[1][name()='rhs']">
-        <td xmlns="http://www.w3.org/1999/xhtml">
+        <td>
           <xsl:if test="@diff and $show.diff.markup != 0">
             <xsl:attribute name="class">
               <xsl:text>diff-</xsl:text>
@@ -2240,7 +2274,7 @@
         </td>
       </xsl:when>
       <xsl:otherwise>
-        <tr xmlns="http://www.w3.org/1999/xhtml" valign="baseline">
+        <tr valign="baseline">
           <td/><td/><td/><td/>
           <td>
             <xsl:if test="@diff and $show.diff.markup != 0">
@@ -2267,7 +2301,7 @@
 
   <!-- wfcnote: well-formedness check note after formal production -->
   <xsl:template match="wfcnote">
-    <div xmlns="http://www.w3.org/1999/xhtml" class="constraint">
+    <div class="constraint">
       <xsl:apply-templates/>
     </div>
   </xsl:template>
@@ -2277,7 +2311,7 @@
   <!-- xtermref: external term reference -->
   <!-- just link to URI provided -->
   <xsl:template match="xnt | xspecref | xtermref">
-    <a xmlns="http://www.w3.org/1999/xhtml" href="{@href}">
+    <a href="{@href}">
       <xsl:apply-templates/>
     </a>
   </xsl:template>
@@ -2292,7 +2326,7 @@
        show up in a spec, but they're easy to handle and you just
        never know. -->
   <xsl:template match="a|div|em|h1|h2|h3|h4|h5|h6|li|ol|pre|ul">
-    <xsl:element name="{local-name(.)}" namespace="http://www.w3.org/1999/xhtml">
+    <xsl:element name="{local-name(.)}">
       <xsl:copy-of select="@*"/>
       <xsl:apply-templates/>
     </xsl:element>
@@ -2300,44 +2334,44 @@
 
   <!-- legacy XML spec stuff -->
   <xsl:template match="htable">
-    <table xmlns="http://www.w3.org/1999/xhtml" summary="HTML Table">
+    <table summary="HTML Table">
       <xsl:copy-of select="@*"/>
       <xsl:apply-templates/>
     </table>
   </xsl:template>
   <xsl:template match="htbody">
-    <tbody xmlns="http://www.w3.org/1999/xhtml">
+    <tbody>
       <xsl:copy-of select="@*"/>
       <xsl:apply-templates/>
     </tbody>
   </xsl:template>
   <xsl:template match="key-term">
-    <b xmlns="http://www.w3.org/1999/xhtml"><xsl:apply-templates/></b>
+    <b><xsl:apply-templates/></b>
   </xsl:template>
   <xsl:template match="statusp">
-    <p xmlns="http://www.w3.org/1999/xhtml">
+    <p>
       <xsl:apply-templates/>
     </p>
   </xsl:template>
 
   <!-- legacy DocBook stuff -->
   <xsl:template match="itemizedlist">
-    <ul xmlns="http://www.w3.org/1999/xhtml">
+    <ul>
       <xsl:apply-templates/>
     </ul>
   </xsl:template>
   <xsl:template match="listitem">
-    <li xmlns="http://www.w3.org/1999/xhtml">
+    <li>
       <xsl:apply-templates/>
     </li>
   </xsl:template>
   <xsl:template match="orderedlist">
-    <ol xmlns="http://www.w3.org/1999/xhtml">
+    <ol>
       <xsl:apply-templates/>
     </ol>
   </xsl:template>
   <xsl:template match="para">
-    <p xmlns="http://www.w3.org/1999/xhtml">
+    <p>
       <xsl:apply-templates/>
     </p>
   </xsl:template>
@@ -2351,38 +2385,48 @@
     <xsl:number count="div1 | inform-div1" format="A "/>
   </xsl:template>
 
-  <xsl:template mode="divnum" match="front/div1 | front//div2 | front//div3 | front//div4 | front//div5"/>
+  <xsl:template mode="divnum"
+    match="front/div1 | front//div2 | front//div3 | front//div4 | front//div5"/>
 
   <xsl:template mode="divnum" match="div2">
     <xsl:number level="multiple" count="div1 | div2" format="1.1 "/>
   </xsl:template>
 
   <xsl:template mode="divnum" match="back//div2">
-    <xsl:number level="multiple" count="div1 | div2 | inform-div1" format="A.1 "/>
+    <xsl:number level="multiple" count="div1 | div2 | inform-div1"
+      format="A.1 "/>
   </xsl:template>
 
   <xsl:template mode="divnum" match="div3">
-    <xsl:number level="multiple" count="div1 | div2 | div3" format="1.1.1 "/>
+    <xsl:number level="multiple" count="div1 | div2 | div3"
+      format="1.1.1 "/>
   </xsl:template>
 
   <xsl:template mode="divnum" match="back//div3">
-    <xsl:number level="multiple" count="div1 | div2 | div3 | inform-div1" format="A.1.1 "/>
+    <xsl:number level="multiple"
+      count="div1 | div2 | div3 | inform-div1" format="A.1.1 "/>
   </xsl:template>
 
   <xsl:template mode="divnum" match="div4">
-    <xsl:number level="multiple" count="div1 | div2 | div3 | div4" format="1.1.1.1 "/>
+    <xsl:number level="multiple" count="div1 | div2 | div3 | div4"
+      format="1.1.1.1 "/>
   </xsl:template>
 
   <xsl:template mode="divnum" match="back//div4">
-    <xsl:number level="multiple" count="div1 | div2 | div3 | div4 | inform-div1" format="A.1.1.1 "/>
+    <xsl:number level="multiple"
+      count="div1 | div2 | div3 | div4 | inform-div1"
+      format="A.1.1.1 "/>
   </xsl:template>
 
   <xsl:template mode="divnum" match="div5">
-    <xsl:number level="multiple" count="div1 | div2 | div3 | div4 | div5" format="1.1.1.1.1 "/>
+    <xsl:number level="multiple"
+      count="div1 | div2 | div3 | div4 | div5" format="1.1.1.1.1 "/>
   </xsl:template>
 
   <xsl:template mode="divnum" match="back//div5">
-    <xsl:number level="multiple" count="div1 | div2 | div3 | div4 | div5 | inform-div1" format="A.1.1.1.1 "/>
+    <xsl:number level="multiple"
+      count="div1 | div2 | div3 | div4 | div5 | inform-div1"
+      format="A.1.1.1.1 "/>
   </xsl:template>
 
   <!-- mode: notes -->
@@ -2397,14 +2441,14 @@
         </xsl:otherwise>
       </xsl:choose>
     </xsl:variable>
-    <dt xmlns="http://www.w3.org/1999/xhtml">
+    <dt>
       <xsl:text>[</xsl:text>
-      <a name="{$this-note-id}" id="{$this-note-id}" href="#FN-ANCH-{$this-note-id}">
+      <a id="{$this-note-id}" href="#FN-ANCH-{$this-note-id}">
         <xsl:apply-templates select="." mode="number-simple"/>
       </a>
       <xsl:text>]</xsl:text>
     </dt>
-    <dd xmlns="http://www.w3.org/1999/xhtml">
+    <dd>
       <xsl:apply-templates/>
     </dd>
   </xsl:template>
@@ -2425,9 +2469,9 @@
         </xsl:otherwise>
       </xsl:choose>
     </xsl:variable>
-    <p xmlns="http://www.w3.org/1999/xhtml" class="table.footnote">
+    <p class="table.footnote">
       <sup>
-        <a name="{$this-note-id}" id="{$this-note-id}" href="#FN-ANCH-{$this-note-id}">
+        <a id="{$this-note-id}" href="#FN-ANCH-{$this-note-id}">
           <xsl:apply-templates select="parent::footnote" mode="number-simple"/>
           <xsl:text>.</xsl:text>
         </a>
@@ -2450,12 +2494,14 @@
 
   <xsl:template mode="number" match="prod[@diff='add']">
     <xsl:text>[</xsl:text>
-    <xsl:apply-templates select="preceding::prod[not(@diff='add')][1]" mode="number-simple"/>
+    <xsl:apply-templates select="preceding::prod[not(@diff='add')][1]"
+      mode="number-simple"/>
 <!--
   Once again, this could be done right here, but XT won't hear of it.
     <xsl:number level="any" count="prod[not(@diff='add')]"/>
   -->
-    <xsl:number level="any" count="prod[@diff='add']" from="prod[not(@diff='add')]" format="a"/>
+    <xsl:number level="any" count="prod[@diff='add']"
+      from="prod[not(@diff='add')]" format="a"/>
     <xsl:text>]</xsl:text>
   </xsl:template>
 
@@ -2478,7 +2524,7 @@
 
   <!-- mode: ref -->
   <xsl:template match="lhs" mode="ref">
-    <tr xmlns="http://www.w3.org/1999/xhtml" valign="baseline">
+    <tr valign="baseline">
       <td>
         <xsl:if test="ancestor-or-self::*/@diff and $show.diff.markup != 0">
           <xsl:attribute name="class">
@@ -2487,7 +2533,7 @@
           </xsl:attribute>
         </xsl:if>
         <xsl:apply-templates select="ancestor::prod" mode="number"/>
-        <xsl:text>   </xsl:text>
+        <xsl:text>&#xa0;&#xa0;&#xa0;</xsl:text>
       </td>
       <td>
         <xsl:if test="ancestor-or-self::*/@diff and $show.diff.markup != 0">
@@ -2514,15 +2560,21 @@
             <xsl:value-of select="ancestor-or-self::*/@diff"/>
           </xsl:attribute>
         </xsl:if>
-        <xsl:text>   ::=   </xsl:text>
+        <xsl:text>&#xa0;&#xa0;&#xa0;::=&#xa0;&#xa0;&#xa0;</xsl:text>
       </td>
-      <xsl:apply-templates select="following-sibling::*[1][name()='rhs']"/>
+      <xsl:apply-templates
+        select="following-sibling::*[1][name()='rhs']"/>
     </tr>
   </xsl:template>
 
   <xsl:template mode="ref" match="prod">
     <xsl:apply-templates select="lhs" mode="ref"/>
-    <xsl:apply-templates select="rhs[preceding-sibling::*[1][name()!='lhs']] |               com[preceding-sibling::*[1][name()!='rhs']] |               constraint[preceding-sibling::*[1][name()!='rhs']] |               vc[preceding-sibling::*[1][name()!='rhs']] |               wfc[preceding-sibling::*[1][name()!='rhs']]"/>
+    <xsl:apply-templates
+      select="rhs[preceding-sibling::*[1][name()!='lhs']] |
+              com[preceding-sibling::*[1][name()!='rhs']] |
+              constraint[preceding-sibling::*[1][name()!='rhs']] |
+              vc[preceding-sibling::*[1][name()!='rhs']] |
+              wfc[preceding-sibling::*[1][name()!='rhs']]"/>
   </xsl:template>
 
   <!-- mode: text -->
@@ -2533,45 +2585,7 @@
   <!-- mode: toc -->
   <xsl:template mode="toc" match="div1">
     <xsl:apply-templates select="." mode="divnum"/>
-    <a xmlns="http://www.w3.org/1999/xhtml">
-      <xsl:attribute name="href">
-        <xsl:call-template name="href.target">
-          <xsl:with-param name="target" select="."/>
-        </xsl:call-template>
-      </xsl:attribute>
-      <xsl:apply-templates select="head" mode="text"/>
-    </a>
-    <br xmlns="http://www.w3.org/1999/xhtml"/>
-    <xsl:text>
-</xsl:text>
-    <xsl:if test="$toc.level &gt; 1">
-      <xsl:apply-templates select="div2" mode="toc"/>
-    </xsl:if>
-  </xsl:template>
-
-  <xsl:template mode="toc" match="div2">
-    <xsl:text>    </xsl:text>
-    <xsl:apply-templates select="." mode="divnum"/>
-    <a xmlns="http://www.w3.org/1999/xhtml">
-      <xsl:attribute name="href">
-        <xsl:call-template name="href.target">
-          <xsl:with-param name="target" select="."/>
-        </xsl:call-template>
-      </xsl:attribute>
-      <xsl:apply-templates select="head" mode="text"/>
-    </a>
-    <br xmlns="http://www.w3.org/1999/xhtml"/>
-    <xsl:text>
-</xsl:text>
-    <xsl:if test="$toc.level &gt; 2">
-      <xsl:apply-templates select="div3" mode="toc"/>
-    </xsl:if>
-  </xsl:template>
-
-  <xsl:template mode="toc" match="div3">
-    <xsl:text>        </xsl:text>
-    <xsl:apply-templates select="." mode="divnum"/>
-    <a xmlns="http://www.w3.org/1999/xhtml">
+    <a>
       <xsl:attribute name="href">
         <xsl:call-template name="href.target">
           <xsl:with-param name="target" select="."/>
@@ -2579,18 +2593,17 @@
       </xsl:attribute>
       <xsl:apply-templates select="head" mode="text"/>
     </a>
-    <br xmlns="http://www.w3.org/1999/xhtml"/>
-    <xsl:text>
-</xsl:text>
-    <xsl:if test="$toc.level &gt; 3">
-      <xsl:apply-templates select="div4" mode="toc"/>
+    <br/>
+    <xsl:text>&#10;</xsl:text>
+    <xsl:if test="$toc.level &gt; 1">
+      <xsl:apply-templates select="div2" mode="toc"/>
     </xsl:if>
   </xsl:template>
 
-  <xsl:template mode="toc" match="div4">
-    <xsl:text>            </xsl:text>
+  <xsl:template mode="toc" match="div2">
+    <xsl:text>&#xa0;&#xa0;&#xa0;&#xa0;</xsl:text>
     <xsl:apply-templates select="." mode="divnum"/>
-    <a xmlns="http://www.w3.org/1999/xhtml">
+    <a>
       <xsl:attribute name="href">
         <xsl:call-template name="href.target">
           <xsl:with-param name="target" select="."/>
@@ -2598,18 +2611,17 @@
       </xsl:attribute>
       <xsl:apply-templates select="head" mode="text"/>
     </a>
-    <br xmlns="http://www.w3.org/1999/xhtml"/>
-    <xsl:text>
-</xsl:text>
-    <xsl:if test="$toc.level &gt; 4">
-      <xsl:apply-templates select="div5" mode="toc"/>
+    <br/>
+    <xsl:text>&#10;</xsl:text>
+    <xsl:if test="$toc.level &gt; 2">
+      <xsl:apply-templates select="div3" mode="toc"/>
     </xsl:if>
   </xsl:template>
 
-  <xsl:template mode="toc" match="div5">
-    <xsl:text>                </xsl:text>
+  <xsl:template mode="toc" match="div3">
+    <xsl:text>&#xa0;&#xa0;&#xa0;&#xa0;&#xa0;&#xa0;&#xa0;&#xa0;</xsl:text>
     <xsl:apply-templates select="." mode="divnum"/>
-    <a xmlns="http://www.w3.org/1999/xhtml">
+    <a>
       <xsl:attribute name="href">
         <xsl:call-template name="href.target">
           <xsl:with-param name="target" select="."/>
@@ -2617,14 +2629,49 @@
       </xsl:attribute>
       <xsl:apply-templates select="head" mode="text"/>
     </a>
-    <br xmlns="http://www.w3.org/1999/xhtml"/>
-    <xsl:text>
-</xsl:text>
+    <br/>
+    <xsl:text>&#10;</xsl:text>
+    <xsl:if test="$toc.level &gt; 3">
+      <xsl:apply-templates select="div4" mode="toc"/>
+    </xsl:if>
+  </xsl:template>
+
+  <xsl:template mode="toc" match="div4">
+    <xsl:text>&#xa0;&#xa0;&#xa0;&#xa0;&#xa0;&#xa0;&#xa0;&#xa0;&#xa0;&#xa0;&#xa0;&#xa0;</xsl:text>
+    <xsl:apply-templates select="." mode="divnum"/>
+    <a>
+      <xsl:attribute name="href">
+        <xsl:call-template name="href.target">
+          <xsl:with-param name="target" select="."/>
+        </xsl:call-template>
+      </xsl:attribute>
+      <xsl:apply-templates select="head" mode="text"/>
+    </a>
+    <br/>
+    <xsl:text>&#10;</xsl:text>
+    <xsl:if test="$toc.level &gt; 4">
+      <xsl:apply-templates select="div5" mode="toc"/>
+    </xsl:if>
+  </xsl:template>
+
+  <xsl:template mode="toc" match="div5">
+    <xsl:text>&#xa0;&#xa0;&#xa0;&#xa0;&#xa0;&#xa0;&#xa0;&#xa0;&#xa0;&#xa0;&#xa0;&#xa0;&#xa0;&#xa0;&#xa0;&#xa0;</xsl:text>
+    <xsl:apply-templates select="." mode="divnum"/>
+    <a>
+      <xsl:attribute name="href">
+        <xsl:call-template name="href.target">
+          <xsl:with-param name="target" select="."/>
+        </xsl:call-template>
+      </xsl:attribute>
+      <xsl:apply-templates select="head" mode="text"/>
+    </a>
+    <br/>
+    <xsl:text>&#10;</xsl:text>
   </xsl:template>
 
   <xsl:template mode="toc" match="inform-div1">
     <xsl:apply-templates select="." mode="divnum"/>
-    <a xmlns="http://www.w3.org/1999/xhtml">
+    <a>
       <xsl:attribute name="href">
         <xsl:call-template name="href.target">
           <xsl:with-param name="target" select="."/>
@@ -2633,16 +2680,15 @@
       <xsl:apply-templates select="head" mode="text"/>
     </a>
     <xsl:text> (Non-Normative)</xsl:text>
-    <br xmlns="http://www.w3.org/1999/xhtml"/>
-    <xsl:text>
-</xsl:text>
+    <br/>
+    <xsl:text>&#10;</xsl:text>
     <xsl:if test="$toc.level &gt; 2">
       <xsl:apply-templates select="div2" mode="toc"/>
     </xsl:if>
   </xsl:template>
 
   <xsl:template name="css">
-    <style xmlns="http://www.w3.org/1999/xhtml" type="text/css">
+    <style type="text/css">
       <xsl:text>
 code           { font-family: monospace; }
 
@@ -2679,7 +2725,7 @@
       </xsl:if>
       <xsl:value-of select="$additional.css"/>
     </style>
-    <link xmlns="http://www.w3.org/1999/xhtml" rel="stylesheet" type="text/css">
+    <link rel="stylesheet" type="text/css">
       <xsl:attribute name="href">
         <xsl:text>http://www.w3.org/StyleSheets/TR/</xsl:text>
         <xsl:choose>
@@ -2687,7 +2733,9 @@
           <xsl:otherwise>
             <xsl:choose>
 	      <!-- Editor's review drafts are a special case. -->
-              <xsl:when test="/spec/@w3c-doctype='review'          or contains(/spec/header/w3c-doctype, 'Editor')">W3C-ED</xsl:when>
+              <xsl:when test="/spec/@w3c-doctype='review'
+			      or contains(/spec/header/w3c-doctype, 'Editor')"
+			>W3C-ED</xsl:when>
               <xsl:when test="/spec/@w3c-doctype='wd'">W3C-WD</xsl:when>
               <xsl:when test="/spec/@w3c-doctype='rec'">W3C-REC</xsl:when>
               <xsl:when test="/spec/@w3c-doctype='pr'">W3C-PR</xsl:when>
@@ -2757,7 +2805,7 @@
     </xsl:call-template>
   </xsl:variable>
   <xsl:if test="$conditional = 0 or $node/@id">
-    <a xmlns="http://www.w3.org/1999/xhtml" name="{$id}" id="{$id}"/>
+    <a id="{$id}"/>
   </xsl:if>
 </xsl:template>
 
Binary file ttml11/spec/xsd/schema.zip has changed
--- a/ttml11/spec/xsd/ttml11-animation.xsd	Tue Jul 09 11:28:27 2013 -0600
+++ b/ttml11/spec/xsd/ttml11-animation.xsd	Tue Jul 09 14:39:28 2013 -0600
@@ -3,11 +3,11 @@
   xmlns:tt="http://www.w3.org/ns/ttml"
   xmlns:ttm="http://www.w3.org/ns/ttml#metadata"
   xmlns:tts="http://www.w3.org/ns/ttml#styling">
-  <xs:include schemaLocation="ttaf1-dfxp-core-attribs.xsd"/>
-  <xs:include schemaLocation="ttaf1-dfxp-timing-attribs.xsd"/>
-  <xs:include schemaLocation="ttaf1-dfxp-metadata.xsd"/>
+  <xs:include schemaLocation="ttml11-core-attribs.xsd"/>
+  <xs:include schemaLocation="ttml11-timing-attribs.xsd"/>
+  <xs:include schemaLocation="ttml11-metadata.xsd"/>
   <xs:import namespace="http://www.w3.org/ns/ttml#styling"
-    schemaLocation="ttaf1-dfxp-styling-attribs.xsd"/>
+    schemaLocation="ttml11-styling-attribs.xsd"/>
   <xs:attributeGroup name="set.attlist">
     <xs:attributeGroup ref="tt:Core.attrib.class" />
     <xs:attributeGroup ref="tt:Timed.attrib.class" />
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/ttml11/spec/xsd/ttml11-bindings.xjb	Tue Jul 09 14:39:28 2013 -0600
@@ -0,0 +1,19 @@
+<jxb:bindings version="2.1" xmlns:jxb="http://java.sun.com/xml/ns/jaxb" xmlns:xs="http://www.w3.org/2001/XMLSchema">
+  <jxb:bindings schemaLocation="ttml11-styling.xsd">
+    <jxb:bindings node="//xs:attributeGroup[@name='StyleBinding.attrib.class']/xs:attribute[@name='style']">
+      <jxb:property name="styleAttribute"/>
+    </jxb:bindings>
+  </jxb:bindings>
+  <jxb:bindings schemaLocation="ttml11-parameter-items.xsd">
+    <jxb:bindings node=".//xs:attributeGroup[@name='extension.attlist']">
+      <jxb:bindings node="./xs:attribute[@name='value']">
+        <jxb:property name="extensionValue"/>
+      </jxb:bindings>
+    </jxb:bindings>
+    <jxb:bindings node=".//xs:attributeGroup[@name='feature.attlist']">
+      <jxb:bindings node="./xs:attribute[@name='value']">
+        <jxb:property name="featureValue"/>
+      </jxb:bindings>
+    </jxb:bindings>
+  </jxb:bindings>
+</jxb:bindings>
\ No newline at end of file
--- a/ttml11/spec/xsd/ttml11-content.xsd	Tue Jul 09 11:28:27 2013 -0600
+++ b/ttml11/spec/xsd/ttml11-content.xsd	Tue Jul 09 14:39:28 2013 -0600
@@ -3,14 +3,14 @@
   xmlns:tt="http://www.w3.org/ns/ttml"
   xmlns:ttm="http://www.w3.org/ns/ttml#metadata"
   xmlns:tts="http://www.w3.org/ns/ttml#styling">
-  <xs:include schemaLocation="ttaf1-dfxp-core-attribs.xsd"/>
-  <xs:include schemaLocation="ttaf1-dfxp-timing-attribs.xsd"/>
-  <xs:include schemaLocation="ttaf1-dfxp-metadata.xsd"/>
-  <xs:include schemaLocation="ttaf1-dfxp-animation.xsd"/>
-  <xs:include schemaLocation="ttaf1-dfxp-layout.xsd"/>
-  <xs:include schemaLocation="ttaf1-dfxp-styling.xsd"/>
+  <xs:include schemaLocation="ttml11-core-attribs.xsd"/>
+  <xs:include schemaLocation="ttml11-timing-attribs.xsd"/>
+  <xs:include schemaLocation="ttml11-metadata.xsd"/>
+  <xs:include schemaLocation="ttml11-animation.xsd"/>
+  <xs:include schemaLocation="ttml11-layout.xsd"/>
+  <xs:include schemaLocation="ttml11-styling.xsd"/>
   <xs:import namespace="http://www.w3.org/ns/ttml#metadata"
-    schemaLocation="ttaf1-dfxp-metadata-attribs.xsd"/>
+    schemaLocation="ttml11-metadata-attribs.xsd"/>
   <xs:attributeGroup name="body.attlist">
     <xs:attributeGroup ref="tt:Core.attrib.class"/>
     <xs:attributeGroup ref="tt:TimedContainer.attrib.class"/>
--- a/ttml11/spec/xsd/ttml11-core-attribs.xsd	Tue Jul 09 11:28:27 2013 -0600
+++ b/ttml11/spec/xsd/ttml11-core-attribs.xsd	Tue Jul 09 14:39:28 2013 -0600
@@ -11,12 +11,12 @@
     <xs:attributeGroup ref="tt:Core.ID.attrib.class"/>
     <xs:attribute ref="xml:lang"/>
     <xs:attribute ref="xml:space"/>
-    <xs:anyAttribute namespace="##other"/>
+    <xs:anyAttribute namespace="##other" processContents="lax"/>
   </xs:attributeGroup>
   <xs:attributeGroup name="Core.required.attrib.class">
     <xs:attributeGroup ref="tt:Core.ID.attrib.class"/>
     <xs:attribute ref="xml:lang" use="required"/>
     <xs:attribute ref="xml:space"/>
-    <xs:anyAttribute namespace="##other"/>
+    <xs:anyAttribute namespace="##other" processContents="lax"/>
   </xs:attributeGroup>
 </xs:schema>
--- a/ttml11/spec/xsd/ttml11-datatypes.xsd	Tue Jul 09 11:28:27 2013 -0600
+++ b/ttml11/spec/xsd/ttml11-datatypes.xsd	Tue Jul 09 14:39:28 2013 -0600
@@ -3,10 +3,7 @@
         xml:lang="en" xmlns:xs="http://www.w3.org/2001/XMLSchema"
         xmlns:ttd="http://www.w3.org/ns/ttml#datatype">
   <xs:simpleType name="alpha">
-    <xs:restriction base="xs:float">
-      <xs:minInclusive value="0"/>
-      <xs:maxInclusive value="1"/>
-    </xs:restriction>
+    <xs:restriction base="xs:float"/>
   </xs:simpleType>
   <xs:simpleType name="agent">
     <xs:restriction base="xs:IDREFS"/>
@@ -102,7 +99,7 @@
     </xs:restriction>
   </xs:simpleType>
   <xs:simpleType name="frameRate">
-    <xs:restriction base="xs:nonNegativeInteger"/>
+    <xs:restriction base="xs:positiveInteger"/>
   </xs:simpleType>
   <xs:simpleType name="frameRateMultiplier">
     <xs:annotation>
@@ -170,7 +167,7 @@
     <xs:annotation>
       <xs:documentation>alpha</xs:documentation>
     </xs:annotation>
-    <xs:restriction base="xs:string"/>
+    <xs:restriction base="ttd:alpha"/>
   </xs:simpleType>
   <xs:simpleType name="origin">
     <xs:annotation>
@@ -202,10 +199,26 @@
     <xs:restriction base="xs:anyURI"/>
   </xs:simpleType>
   <xs:simpleType name="role">
+    <xs:restriction>
+      <xs:simpleType>
+        <xs:list itemType="ttd:roleItem"/>
+      </xs:simpleType>
+    </xs:restriction>
+  </xs:simpleType>
+  <xs:simpleType name="roleItem">
     <xs:annotation>
       <xs:documentation>metadataRoleBaseType | "x-"string</xs:documentation>
     </xs:annotation>
-    <xs:restriction base="xs:NMTOKENS"/>
+    <xs:union>
+      <xs:simpleType>
+        <xs:restriction base="ttd:metadataRoleBaseType"/>
+      </xs:simpleType>
+      <xs:simpleType>
+        <xs:restriction base="xs:NMTOKEN">
+          <xs:pattern value="x-\c+"/>
+        </xs:restriction>
+      </xs:simpleType>
+    </xs:union>
   </xs:simpleType>
   <xs:simpleType name="showBackground">
     <xs:restriction base="xs:token">
@@ -226,14 +239,81 @@
     </xs:restriction>
   </xs:simpleType>
   <xs:simpleType name="textDecoration">
-    <xs:restriction base="xs:token">
+    <xs:annotation>
+      <xs:documentation>none | [ [ underline | noUnderline ] || [ lineThrough | noLineThrough ] || [ overline | noOverline ] ]</xs:documentation>
+    </xs:annotation>
+    <xs:restriction base="xs:string">
       <xs:enumeration value="none"/>
       <xs:enumeration value="underline"/>
       <xs:enumeration value="noUnderline"/>
+      <xs:enumeration value="lineThrough"/>
+      <xs:enumeration value="noLineThrough"/>
       <xs:enumeration value="overline"/>
       <xs:enumeration value="noOverline"/>
-      <xs:enumeration value="lineThrough"/>
-      <xs:enumeration value="noLineThrough"/>
+      <xs:enumeration value="noUnderline noLineThrough"/>
+      <xs:enumeration value="noLineThrough noUnderline"/>
+      <xs:enumeration value="noUnderline lineThrough"/>
+      <xs:enumeration value="lineThrough noUnderline"/>
+      <xs:enumeration value="underline noLineThrough"/>
+      <xs:enumeration value="noLineThrough underline"/>
+      <xs:enumeration value="underline lineThrough"/>
+      <xs:enumeration value="lineThrough underline"/>
+      <xs:enumeration value="noUnderline noOverline"/>
+      <xs:enumeration value="noOverline noUnderline"/>
+      <xs:enumeration value="noUnderline overline"/>
+      <xs:enumeration value="overline noUnderline"/>
+      <xs:enumeration value="underline noOverline"/>
+      <xs:enumeration value="noOverline underline"/>
+      <xs:enumeration value="underline overline"/>
+      <xs:enumeration value="overline underline"/>
+      <xs:enumeration value="noUnderline noLineThrough noOverline"/>
+      <xs:enumeration value="noUnderline noOverline noLineThrough"/>
+      <xs:enumeration value="noLineThrough noUnderline noOverline"/>
+      <xs:enumeration value="noLineThrough noOverline noUnderline"/>
+      <xs:enumeration value="noOverline noUnderline noLineThrough"/>
+      <xs:enumeration value="noOverline noLineThrough noUnderline"/>
+      <xs:enumeration value="noUnderline noLineThrough overline"/>
+      <xs:enumeration value="noUnderline overline noLineThrough"/>
+      <xs:enumeration value="noLineThrough noUnderline overline"/>
+      <xs:enumeration value="noLineThrough overline noUnderline"/>
+      <xs:enumeration value="overline noUnderline noLineThrough"/>
+      <xs:enumeration value="overline noLineThrough noUnderline"/>
+      <xs:enumeration value="noUnderline lineThrough noOverline"/>
+      <xs:enumeration value="noUnderline noOverline lineThrough"/>
+      <xs:enumeration value="lineThrough noUnderline noOverline"/>
+      <xs:enumeration value="lineThrough noOverline noUnderline"/>
+      <xs:enumeration value="noOverline noUnderline lineThrough"/>
+      <xs:enumeration value="noOverline lineThrough noUnderline"/>
+      <xs:enumeration value="noUnderline lineThrough overline"/>
+      <xs:enumeration value="noUnderline overline lineThrough"/>
+      <xs:enumeration value="lineThrough noUnderline overline"/>
+      <xs:enumeration value="lineThrough overline noUnderline"/>
+      <xs:enumeration value="overline noUnderline lineThrough"/>
+      <xs:enumeration value="overline lineThrough noUnderline"/>
+      <xs:enumeration value="underline noLineThrough noOverline"/>
+      <xs:enumeration value="underline noOverline noLineThrough"/>
+      <xs:enumeration value="noLineThrough underline noOverline"/>
+      <xs:enumeration value="noLineThrough noOverline underline"/>
+      <xs:enumeration value="noOverline underline noLineThrough"/>
+      <xs:enumeration value="noOverline noLineThrough underline"/>
+      <xs:enumeration value="underline noLineThrough overline"/>
+      <xs:enumeration value="underline overline noLineThrough"/>
+      <xs:enumeration value="noLineThrough underline overline"/>
+      <xs:enumeration value="noLineThrough overline underline"/>
+      <xs:enumeration value="overline underline noLineThrough"/>
+      <xs:enumeration value="overline noLineThrough underline"/>
+      <xs:enumeration value="underline lineThrough noOverline"/>
+      <xs:enumeration value="underline noOverline lineThrough"/>
+      <xs:enumeration value="lineThrough underline noOverline"/>
+      <xs:enumeration value="lineThrough noOverline underline"/>
+      <xs:enumeration value="noOverline underline lineThrough"/>
+      <xs:enumeration value="noOverline lineThrough underline"/>
+      <xs:enumeration value="underline lineThrough overline"/>
+      <xs:enumeration value="underline overline lineThrough"/>
+      <xs:enumeration value="lineThrough underline overline"/>
+      <xs:enumeration value="lineThrough overline underline"/>
+      <xs:enumeration value="overline underline lineThrough"/>
+      <xs:enumeration value="overline lineThrough underline"/>
     </xs:restriction>
   </xs:simpleType>
   <xs:simpleType name="textOutline">
--- a/ttml11/spec/xsd/ttml11-document.xsd	Tue Jul 09 11:28:27 2013 -0600
+++ b/ttml11/spec/xsd/ttml11-document.xsd	Tue Jul 09 14:39:28 2013 -0600
@@ -5,15 +5,15 @@
   xmlns:ttp="http://www.w3.org/ns/ttml#parameter"
   xmlns:tts="http://www.w3.org/ns/ttml#styling">
   <xs:import namespace="http://www.w3.org/ns/ttml#metadata"
-    schemaLocation="ttaf1-dfxp-metadata-items.xsd"/>
+    schemaLocation="ttml11-metadata-items.xsd"/>
   <xs:import namespace="http://www.w3.org/ns/ttml#parameter"
-    schemaLocation="ttaf1-dfxp-parameter-items.xsd"/>
+    schemaLocation="ttml11-parameter-items.xsd"/>
   <xs:import namespace="http://www.w3.org/ns/ttml#styling"
-    schemaLocation="ttaf1-dfxp-styling-attribs.xsd"/>
-  <xs:include schemaLocation="ttaf1-dfxp-core-attribs.xsd"/>
-  <xs:include schemaLocation="ttaf1-dfxp-timing-attribs.xsd"/>
-  <xs:include schemaLocation="ttaf1-dfxp-head.xsd"/>
-  <xs:include schemaLocation="ttaf1-dfxp-content.xsd"/>
+    schemaLocation="ttml11-styling-attribs.xsd"/>
+  <xs:include schemaLocation="ttml11-core-attribs.xsd"/>
+  <xs:include schemaLocation="ttml11-timing-attribs.xsd"/>
+  <xs:include schemaLocation="ttml11-head.xsd"/>
+  <xs:include schemaLocation="ttml11-content.xsd"/>
   <xs:attributeGroup name="tt.attlist">
     <xs:attributeGroup ref="tt:Core.required.attrib.class"/>
     <xs:attributeGroup ref="ttp:Parameter.attrib.class"/>
--- a/ttml11/spec/xsd/ttml11-head.xsd	Tue Jul 09 11:28:27 2013 -0600
+++ b/ttml11/spec/xsd/ttml11-head.xsd	Tue Jul 09 14:39:28 2013 -0600
@@ -4,11 +4,11 @@
   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">
-  <xs:include schemaLocation="ttaf1-dfxp-core-attribs.xsd"/>
-  <xs:include schemaLocation="ttaf1-dfxp-metadata.xsd"/>
-  <xs:include schemaLocation="ttaf1-dfxp-parameters.xsd"/>
-  <xs:include schemaLocation="ttaf1-dfxp-styling.xsd"/>
-  <xs:include schemaLocation="ttaf1-dfxp-layout.xsd"/>
+  <xs:include schemaLocation="ttml11-core-attribs.xsd"/>
+  <xs:include schemaLocation="ttml11-metadata.xsd"/>
+  <xs:include schemaLocation="ttml11-parameters.xsd"/>
+  <xs:include schemaLocation="ttml11-styling.xsd"/>
+  <xs:include schemaLocation="ttml11-layout.xsd"/>
   <xs:attributeGroup name="head.attlist">
     <xs:attributeGroup ref="tt:Core.attrib.class"/>
   </xs:attributeGroup>
--- a/ttml11/spec/xsd/ttml11-layout.xsd	Tue Jul 09 11:28:27 2013 -0600
+++ b/ttml11/spec/xsd/ttml11-layout.xsd	Tue Jul 09 14:39:28 2013 -0600
@@ -3,13 +3,13 @@
   xmlns:tt="http://www.w3.org/ns/ttml"
   xmlns:ttm="http://www.w3.org/ns/ttml#metadata"
   xmlns:tts="http://www.w3.org/ns/ttml#styling">
-  <xs:include schemaLocation="ttaf1-dfxp-core-attribs.xsd"/>
-  <xs:include schemaLocation="ttaf1-dfxp-timing-attribs.xsd"/>
-  <xs:include schemaLocation="ttaf1-dfxp-metadata.xsd"/>
-  <xs:include schemaLocation="ttaf1-dfxp-animation.xsd"/>
-  <xs:include schemaLocation="ttaf1-dfxp-styling.xsd"/>
+  <xs:include schemaLocation="ttml11-core-attribs.xsd"/>
+  <xs:include schemaLocation="ttml11-timing-attribs.xsd"/>
+  <xs:include schemaLocation="ttml11-metadata.xsd"/>
+  <xs:include schemaLocation="ttml11-animation.xsd"/>
+  <xs:include schemaLocation="ttml11-styling.xsd"/>
   <xs:import namespace="http://www.w3.org/ns/ttml#styling"
-    schemaLocation="ttaf1-dfxp-styling-attribs.xsd"/>
+    schemaLocation="ttml11-styling-attribs.xsd"/>
   <xs:attributeGroup name="RegionBinding.attrib.class">
     <xs:attribute name="region" type="xs:IDREF"/>
   </xs:attributeGroup>
--- a/ttml11/spec/xsd/ttml11-metadata-attribs.xsd	Tue Jul 09 11:28:27 2013 -0600
+++ b/ttml11/spec/xsd/ttml11-metadata-attribs.xsd	Tue Jul 09 14:39:28 2013 -0600
@@ -3,7 +3,7 @@
   xmlns:ttd="http://www.w3.org/ns/ttml#datatype"
   xmlns:ttm="http://www.w3.org/ns/ttml#metadata">
   <xs:import namespace="http://www.w3.org/ns/ttml#datatype"
-    schemaLocation="ttaf1-dfxp-datatypes.xsd"/>
+    schemaLocation="ttml11-datatypes.xsd"/>
   <xs:attribute name="agent" type="ttd:agent"/>
   <xs:attribute name="role" type="ttd:role"/>
   <xs:attributeGroup name="Metadata.attrib.class">
--- a/ttml11/spec/xsd/ttml11-metadata-items.xsd	Tue Jul 09 11:28:27 2013 -0600
+++ b/ttml11/spec/xsd/ttml11-metadata-items.xsd	Tue Jul 09 14:39:28 2013 -0600
@@ -4,18 +4,17 @@
   xmlns:ttd="http://www.w3.org/ns/ttml#datatype"
   xmlns:ttm="http://www.w3.org/ns/ttml#metadata">
   <xs:import namespace="http://www.w3.org/ns/ttml#datatype"
-    schemaLocation="ttaf1-dfxp-datatypes.xsd"/>
+    schemaLocation="ttml11-datatypes.xsd"/>
   <xs:import namespace="http://www.w3.org/ns/ttml"
-    schemaLocation="ttaf1-dfxp-core-attribs.xsd"/>
-  <xs:include schemaLocation="ttaf1-dfxp-metadata-attribs.xsd"/>
+    schemaLocation="ttml11-core-attribs.xsd"/>
+  <xs:include schemaLocation="ttml11-metadata-attribs.xsd"/>
   <xs:attributeGroup name="actor.attlist">
     <xs:attributeGroup ref="tt:Core.attrib.class"/>
-    <xs:attribute name="agent" type="xs:IDREF"/>
+    <xs:attribute name="agent" type="xs:IDREF" use="required"/>
   </xs:attributeGroup>
   <xs:attributeGroup name="agent.attlist">
     <xs:attributeGroup ref="tt:Core.attrib.class"/>
-    <xs:attribute name="type" type="ttd:metadataAgentType"
-    use="required"/>
+    <xs:attribute name="type" type="ttd:metadataAgentType" use="required"/>
   </xs:attributeGroup>
   <xs:attributeGroup name="copyright.attlist">
     <xs:attributeGroup ref="tt:Core.attrib.class"/>
@@ -25,7 +24,7 @@
   </xs:attributeGroup>
   <xs:attributeGroup name="name.attlist">
     <xs:attributeGroup ref="tt:Core.attrib.class"/>
-    <xs:attribute name="type" type="ttd:metadataNameType"/>
+    <xs:attribute name="type" type="ttd:metadataNameType" use="required"/>
   </xs:attributeGroup>
   <xs:attributeGroup name="title.attlist">
     <xs:attributeGroup ref="tt:Core.attrib.class"/>
--- a/ttml11/spec/xsd/ttml11-metadata.xsd	Tue Jul 09 11:28:27 2013 -0600
+++ b/ttml11/spec/xsd/ttml11-metadata.xsd	Tue Jul 09 14:39:28 2013 -0600
@@ -2,16 +2,16 @@
   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">
-  <xs:include schemaLocation="ttaf1-dfxp-core-attribs.xsd"/>
+  <xs:include schemaLocation="ttml11-core-attribs.xsd"/>
   <xs:import namespace="http://www.w3.org/ns/ttml#metadata"
-    schemaLocation="ttaf1-dfxp-metadata-items.xsd"/>
+    schemaLocation="ttml11-metadata-items.xsd"/>
   <xs:attributeGroup name="metadata.attlist">
     <xs:attributeGroup ref="tt:Core.attrib.class"/>
+    <xs:attributeGroup ref="ttm:Metadata.attrib.class"/>
   </xs:attributeGroup>
-  <xs:complexType name="metadata.eltype" mixed="true">
+  <xs:complexType name="metadata.eltype">
     <xs:sequence>
-      <xs:any namespace="##other" processContents="lax" minOccurs="0"
-        maxOccurs="unbounded"/>
+      <xs:any namespace="##other" processContents="lax" minOccurs="0" maxOccurs="unbounded"/>
     </xs:sequence>
     <xs:attributeGroup ref="tt:metadata.attlist"/>
   </xs:complexType>
--- a/ttml11/spec/xsd/ttml11-parameter-attribs.xsd	Tue Jul 09 11:28:27 2013 -0600
+++ b/ttml11/spec/xsd/ttml11-parameter-attribs.xsd	Tue Jul 09 14:39:28 2013 -0600
@@ -3,7 +3,7 @@
   xmlns:ttd="http://www.w3.org/ns/ttml#datatype"
   xmlns:ttp="http://www.w3.org/ns/ttml#parameter">
   <xs:import namespace="http://www.w3.org/ns/ttml#datatype"
-    schemaLocation="ttaf1-dfxp-datatypes.xsd"/>
+    schemaLocation="ttml11-datatypes.xsd"/>
   <xs:attribute name="cellResolution" type="ttd:cellResolution"/>
   <xs:attribute name="clockMode" type="ttd:clockMode"/>
   <xs:attribute name="dropMode" type="ttd:dropMode"/>
--- a/ttml11/spec/xsd/ttml11-parameter-items.xsd	Tue Jul 09 11:28:27 2013 -0600
+++ b/ttml11/spec/xsd/ttml11-parameter-items.xsd	Tue Jul 09 14:39:28 2013 -0600
@@ -6,37 +6,38 @@
   <xs:import namespace="http://www.w3.org/XML/1998/namespace"
     schemaLocation="xml.xsd"/>
   <xs:import namespace="http://www.w3.org/ns/ttml#datatype"
-    schemaLocation="ttaf1-dfxp-datatypes.xsd"/>
+    schemaLocation="ttml11-datatypes.xsd"/>
   <xs:import namespace="http://www.w3.org/ns/ttml"
-    schemaLocation="ttaf1-dfxp-core-attribs.xsd"/>
-  <xs:include schemaLocation="ttaf1-dfxp-parameter-attribs.xsd"/>
+    schemaLocation="ttml11-core-attribs.xsd"/>
+  <xs:include schemaLocation="ttml11-parameter-attribs.xsd"/>
   <xs:attributeGroup name="profile.attlist">
     <xs:attributeGroup ref="tt:Core.ID.attrib.class"/>
     <xs:attribute name="use" type="ttd:profile"/>
-    <xs:anyAttribute namespace="##other"/>
+    <xs:anyAttribute namespace="##other" processContents="lax"/>
   </xs:attributeGroup>
   <xs:attributeGroup name="features.attlist">
     <xs:attributeGroup ref="tt:Core.ID.attrib.class"/>
     <xs:attribute ref="xml:base"/>
-    <xs:anyAttribute namespace="##other"/>
+    <xs:anyAttribute namespace="##other" processContents="lax"/>
   </xs:attributeGroup>
   <xs:attributeGroup name="feature.attlist">
     <xs:attributeGroup ref="tt:Core.ID.attrib.class"/>
     <xs:attribute name="value" type="ttd:featureValue"/>
-    <xs:anyAttribute namespace="##other"/>
+    <xs:anyAttribute namespace="##other" processContents="lax"/>
   </xs:attributeGroup>
   <xs:attributeGroup name="extensions.attlist">
     <xs:attributeGroup ref="tt:Core.ID.attrib.class"/>
     <xs:attribute ref="xml:base"/>
-    <xs:anyAttribute namespace="##other"/>
+    <xs:anyAttribute namespace="##other" processContents="lax"/>
   </xs:attributeGroup>
   <xs:attributeGroup name="extension.attlist">
     <xs:attributeGroup ref="tt:Core.ID.attrib.class"/>
     <xs:attribute name="value" type="ttd:extensionValue"/>
-    <xs:anyAttribute namespace="##other"/>
+    <xs:anyAttribute namespace="##other" processContents="lax"/>
   </xs:attributeGroup>
   <xs:complexType name="profile.eltype">
     <xs:sequence>
+      <xs:group ref="tt:Metadata.class" minOccurs="0" maxOccurs="unbounded"/>
       <xs:element ref="ttp:features" minOccurs="0" maxOccurs="unbounded"/>
       <xs:element ref="ttp:extensions" minOccurs="0" maxOccurs="unbounded"/>
     </xs:sequence>
@@ -44,27 +45,29 @@
   </xs:complexType>
   <xs:complexType name="features.eltype">
     <xs:sequence>
+      <xs:group ref="tt:Metadata.class" minOccurs="0" maxOccurs="unbounded"/>
       <xs:element ref="ttp:feature" minOccurs="0" maxOccurs="unbounded"/>
     </xs:sequence>
     <xs:attributeGroup ref="ttp:features.attlist"/>
   </xs:complexType>
   <xs:complexType name="feature.eltype">
     <xs:simpleContent>
-	  <xs:extension base="ttd:featureDesignator">
-	    <xs:attributeGroup ref="ttp:feature.attlist"/>
+      <xs:extension base="ttd:featureDesignator">
+        <xs:attributeGroup ref="ttp:feature.attlist"/>
       </xs:extension>
     </xs:simpleContent>
   </xs:complexType>
   <xs:complexType name="extensions.eltype">
     <xs:sequence>
+      <xs:group ref="tt:Metadata.class" minOccurs="0" maxOccurs="unbounded"/>
       <xs:element ref="ttp:extension" minOccurs="0" maxOccurs="unbounded"/>
     </xs:sequence>
     <xs:attributeGroup ref="ttp:extensions.attlist"/>
   </xs:complexType>
   <xs:complexType name="extension.eltype">
     <xs:simpleContent>
-	  <xs:extension base="ttd:extensionDesignator">
-	    <xs:attributeGroup ref="ttp:extension.attlist"/>
+      <xs:extension base="ttd:extensionDesignator">
+        <xs:attributeGroup ref="ttp:extension.attlist"/>
       </xs:extension>
     </xs:simpleContent>
   </xs:complexType>
--- a/ttml11/spec/xsd/ttml11-parameters.xsd	Tue Jul 09 11:28:27 2013 -0600
+++ b/ttml11/spec/xsd/ttml11-parameters.xsd	Tue Jul 09 14:39:28 2013 -0600
@@ -2,9 +2,9 @@
   xmlns:xs="http://www.w3.org/2001/XMLSchema"
   xmlns:tt="http://www.w3.org/ns/ttml"
   xmlns:ttp="http://www.w3.org/ns/ttml#parameter">
-  <xs:include schemaLocation="ttaf1-dfxp-core-attribs.xsd"/>
+  <xs:include schemaLocation="ttml11-core-attribs.xsd"/>
   <xs:import namespace="http://www.w3.org/ns/ttml#parameter"
-    schemaLocation="ttaf1-dfxp-parameter-items.xsd"/>
+    schemaLocation="ttml11-parameter-items.xsd"/>
   <xs:group name="Parameters.class">
     <xs:choice>
       <xs:group ref="ttp:ParameterItems.class"/>
--- a/ttml11/spec/xsd/ttml11-styling-attribs.xsd	Tue Jul 09 11:28:27 2013 -0600
+++ b/ttml11/spec/xsd/ttml11-styling-attribs.xsd	Tue Jul 09 14:39:28 2013 -0600
@@ -4,7 +4,7 @@
   xmlns:ttd="http://www.w3.org/ns/ttml#datatype"
   xmlns:tts="http://www.w3.org/ns/ttml#styling">
   <xs:import namespace="http://www.w3.org/ns/ttml#datatype"
-    schemaLocation="ttaf1-dfxp-datatypes.xsd"/>
+    schemaLocation="ttml11-datatypes.xsd"/>
   <xs:attribute name="backgroundColor" type="ttd:color"/>
   <xs:attribute name="color" type="ttd:color"/>
   <xs:attribute name="direction" type="ttd:direction"/>
--- a/ttml11/spec/xsd/ttml11-styling.xsd	Tue Jul 09 11:28:27 2013 -0600
+++ b/ttml11/spec/xsd/ttml11-styling.xsd	Tue Jul 09 14:39:28 2013 -0600
@@ -3,10 +3,10 @@
   xmlns:tt="http://www.w3.org/ns/ttml"
   xmlns:ttm="http://www.w3.org/ns/ttml#metadata"
   xmlns:tts="http://www.w3.org/ns/ttml#styling">
-  <xs:include schemaLocation="ttaf1-dfxp-core-attribs.xsd"/>
-  <xs:include schemaLocation="ttaf1-dfxp-metadata.xsd"/>
+  <xs:include schemaLocation="ttml11-core-attribs.xsd"/>
+  <xs:include schemaLocation="ttml11-metadata.xsd"/>
   <xs:import namespace="http://www.w3.org/ns/ttml#styling"
-    schemaLocation="ttaf1-dfxp-styling-attribs.xsd"/>
+    schemaLocation="ttml11-styling-attribs.xsd"/>
   <xs:attributeGroup name="StyleBinding.attrib.class">
     <xs:attribute name="style" type="xs:IDREFS"/>
   </xs:attributeGroup>
--- a/ttml11/spec/xsd/ttml11-timing-attribs.xsd	Tue Jul 09 11:28:27 2013 -0600
+++ b/ttml11/spec/xsd/ttml11-timing-attribs.xsd	Tue Jul 09 14:39:28 2013 -0600
@@ -3,7 +3,7 @@
   xmlns:ttd="http://www.w3.org/ns/ttml#datatype"
   xmlns:tt="http://www.w3.org/ns/ttml">
   <xs:import namespace="http://www.w3.org/ns/ttml#datatype"
-    schemaLocation="ttaf1-dfxp-datatypes.xsd"/>
+    schemaLocation="ttml11-datatypes.xsd"/>
   <xs:attributeGroup name="TimingInterval.attrib.class">
     <xs:attribute name="begin" type="ttd:timeCoordinate"/>
     <xs:attribute name="dur" type="ttd:timeDuration"/>
--- a/ttml11/spec/xsd/ttml11.xsd	Tue Jul 09 11:28:27 2013 -0600
+++ b/ttml11/spec/xsd/ttml11.xsd	Tue Jul 09 14:39:28 2013 -0600
@@ -1,5 +1,5 @@
 <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">
-  <xs:include schemaLocation="ttaf1-dfxp-document.xsd"/>
+  <xs:include schemaLocation="ttml11-document.xsd"/>
 </xs:schema>
--- a/ttml11/spec/xsd/xml.xsd	Tue Jul 09 11:28:27 2013 -0600
+++ b/ttml11/spec/xsd/xml.xsd	Tue Jul 09 14:39:28 2013 -0600
@@ -2,7 +2,20 @@
   xmlns:xs="http://www.w3.org/2001/XMLSchema">
   <xs:attribute name="base" type="xs:anyURI"/>
   <xs:attribute name="id" type="xs:ID"/>
-  <xs:attribute name="lang" type="xs:language"/>
+  <xs:attribute name="lang">
+    <xs:simpleType>
+      <xs:union>
+        <xs:simpleType>
+          <xs:restriction base="xs:language"/>
+        </xs:simpleType>
+        <xs:simpleType>
+          <xs:restriction base="xs:string">
+            <xs:enumeration value=""/>
+          </xs:restriction>
+        </xs:simpleType>
+      </xs:union>
+    </xs:simpleType>
+  </xs:attribute>
   <xs:attribute name="space">
     <xs:simpleType>
       <xs:restriction base="xs:NCName">