[imsc] Revised IMSC 1.0 to reference TTML 1
authorpal@sandflow.org
Tue, 15 Apr 2014 16:31:53 -0700
changeset 612 52e24aaec29b
parent 611 f502ec0578cd
child 613 588e2b9d6c66
[imsc] Revised IMSC 1.0 to reference TTML 1
ttml-ww-profiles/ttml-ww-profiles.html
ttml-ww-profiles/ttml-ww-profiles.source.html
--- a/ttml-ww-profiles/ttml-ww-profiles.html	Thu Mar 27 10:43:17 2014 -0600
+++ b/ttml-ww-profiles/ttml-ww-profiles.html	Tue Apr 15 16:31:53 2014 -0700
@@ -3,7 +3,7 @@
 <head>
   <meta charset="utf-8">
 
-  <title>TTML Text and Image Profiles for Internet Media Subtitles and Captions</title>
+  <title>TTML Text and Image Profiles for Internet Media Subtitles and Captions 1.0</title>
   
   
   <style type="text/css">
@@ -209,15 +209,15 @@
 
 </style><link rel="stylesheet" href="https://www.w3.org/StyleSheets/TR/W3C-ED"><!--[if lt IE 9]><script src='https://www.w3.org/2008/site/js/html5shiv.js'></script><![endif]--></head>
 
-<body class="h-entry" style="" role="document" id="respecDocument"><div class="head" role="contentinfo" id="respecHeader">
+<body class="h-entry" role="document" id="respecDocument"><div class="head" role="contentinfo" id="respecHeader">
   <p>
     
       <a href="http://www.w3.org/"><img width="72" height="48" src="https://www.w3.org/Icons/w3c_home" alt="W3C"></a>
     
   </p>
-  <h1 class="title p-name" id="title" property="dcterms:title">TTML Text and Image Profiles for Internet Media Subtitles and Captions</h1>
+  <h1 class="title p-name" id="title" property="dcterms:title">TTML Text and Image Profiles for Internet Media Subtitles and Captions 1.0</h1>
   
-  <h2 property="dcterms:issued" datatype="xsd:dateTime" content="2014-02-13T14:52:26.000Z" id="w3c-editor-s-draft-13-february-2014"><abbr title="World Wide Web Consortium">W3C</abbr> Editor's Draft <time class="dt-published" datetime="2014-02-13">13 February 2014</time></h2>
+  <h2 property="dcterms:issued" datatype="xsd:dateTime" content="2014-04-16T06:30:37.000Z" id="w3c-editor-s-draft-15-april-2014"><abbr title="World Wide Web Consortium">W3C</abbr> Editor's Draft <time class="dt-published" datetime="2014-04-15">15 April 2014</time></h2>
   <dl>
     
       <dt>This version:</dt>
@@ -271,14 +271,14 @@
   
   <hr>
 </div>
-  <section id="abstract" class="introductory" property="dcterms:abstract" datatype="" typeof="bibo:Chapter" resource="#ref" rel="bibo:Chapter"><h2 aria-level="1" role="heading" id="h2_abstract">Abstract</h2>
-    <p>This document specifies two profiles of [<cite><a class="bibref" href="#bib-TTML2">TTML2</a></cite>]: a text-only profile and an image-only
-    profile. These profiles are intended to be used across subtitle and caption delivery applications worldwide, thereby
-    simplifying interoperability, consistent rendering and conversion to other subtitling and captioning formats. The text profile
-    is a superset of [<cite><a class="bibref" href="#bib-SDPUS">SDPUS</a></cite>].</p>
+  <section id="abstract" class="introductory" property="dcterms:abstract" datatype="" typeof="bibo:Chapter" resource="#abstract" rel="bibo:Chapter"><h2 aria-level="1" role="heading" id="h2_abstract">Abstract</h2>
+    <p>This document specifies two profiles of [<cite><a class="bibref" href="#bib-TTML1">TTML1</a></cite>]: a text-only profile and an image-only profile. These profiles are
+    intended to be used across subtitle and caption delivery applications worldwide, thereby simplifying interoperability,
+    consistent rendering and conversion to other subtitling and captioning formats. The text profile is a superset of
+    [<cite><a class="bibref" href="#bib-SDPUS">SDPUS</a></cite>].</p>
 
     <p>Both profiles are based on [<cite><a class="bibref" href="#bib-SUBM">SUBM</a></cite>].</p>
-  </section><section id="sotd" class="introductory" typeof="bibo:Chapter" resource="#ref" rel="bibo:Chapter"><h2 aria-level="1" role="heading" id="h2_sotd">Status of This Document</h2>
+  </section><section id="sotd" class="introductory" typeof="bibo:Chapter" resource="#sotd" rel="bibo:Chapter"><h2 aria-level="1" role="heading" id="h2_sotd">Status of This Document</h2>
   
     
       
@@ -289,9 +289,6 @@
           http://www.w3.org/TR/.</em>
         </p>
         
-       <p>
-          </p>
-    
         <p>
           This document was published by the <a href="http://www.w3.org/AudioVideo/TT/">Timed Text Working Group</a> as an Editor's Draft.
           
@@ -344,21 +341,22 @@
       
     
   
-</section><section id="toc"><h2 class="introductory" aria-level="1" role="heading" id="h2_toc">Table of Contents</h2><ul class="toc" role="directory" id="respecContents"><li class="tocline"><a href="#scope" class="tocxref"><span class="secno">1. </span>Scope</a></li><li class="tocline"><a href="#conformance" class="tocxref"><span class="secno">2. </span>Conformance</a></li><li class="tocline"><a href="#profiles" class="tocxref"><span class="secno">3. </span>Profiles</a><ul class="toc"><li class="tocline"><a href="#general" class="tocxref"><span class="secno">3.1 </span>General</a></li><li class="tocline"><a href="#text-profile" class="tocxref"><span class="secno">3.2 </span>Text Profile</a></li><li class="tocline"><a href="#image-profile" class="tocxref"><span class="secno">3.3 </span>Image Profile</a></li></ul></li><li class="tocline"><a href="#common-constraints" class="tocxref"><span class="secno">4. </span>Common Constraints</a><ul class="toc"><li class="tocline"><a href="#document-encoding" class="tocxref"><span class="secno">4.1 </span>Document Encoding</a></li><li class="tocline"><a href="#namespaces" class="tocxref"><span class="secno">4.2 </span>Namespaces</a></li><li class="tocline"><a href="#related-video-object" class="tocxref"><span class="secno">4.3 </span>Related Video Object</a><ul class="toc"><li class="tocline"><a href="#general-1" class="tocxref"><span class="secno">4.3.1 </span>General</a></li><li class="tocline"><a href="#root-container" class="tocxref"><span class="secno">4.3.2 </span>Root Container</a></li><li class="tocline"><a href="#synchronization" class="tocxref"><span class="secno">4.3.3 </span>Synchronization</a></li></ul></li><li class="tocline"><a href="#progressively-decodable" class="tocxref"><span class="secno">4.4 </span>Progressively Decodable</a></li><li class="tocline"><a href="#region" class="tocxref"><span class="secno">4.5 </span>Region</a><ul class="toc"><li class="tocline"><a href="#presented-region" class="tocxref"><span class="secno">4.5.1 </span>Presented Region</a></li><li class="tocline"><a href="#dimensions-and-position" class="tocxref"><span class="secno">4.5.2 </span>Dimensions and Position</a></li><li class="tocline"><a href="#maximum-number" class="tocxref"><span class="secno">4.5.3 </span>Maximum number</a></li></ul></li><li class="tocline"><a href="#hypothetical-render-model" class="tocxref"><span class="secno">4.6 </span>Hypothetical Render Model</a></li><li class="tocline"><a href="#features" class="tocxref"><span class="secno">4.7 </span>Features</a></li></ul></li><li class="tocline"><a href="#text-profile-constraints" class="tocxref"><span class="secno">5. </span>Text Profile Constraints</a><ul class="toc"><li class="tocline"><a href="#profile-designator-and-definition-document" class="tocxref"><span class="secno">5.1 </span>Profile Designator and Definition Document</a></li><li class="tocline"><a href="#recommended-character-sets" class="tocxref"><span class="secno">5.2 </span>Recommended Character Sets</a></li><li class="tocline"><a href="#features-1" class="tocxref"><span class="secno">5.3 </span>Features</a></li></ul></li><li class="tocline"><a href="#image-profile-constraints" class="tocxref"><span class="secno">6. </span>Image Profile Constraints</a><ul class="toc"><li class="tocline"><a href="#profile-designator-and-definition-document-1" class="tocxref"><span class="secno">6.1 </span>Profile Designator and Definition Document</a></li><li class="tocline"><a href="#presented-image" class="tocxref"><span class="secno">6.2 </span>Presented Image</a><ul class="toc"><li class="tocline"><a href="#definition" class="tocxref"><span class="secno">6.2.1 </span>Definition</a></li><li class="tocline"><a href="#number-per-region" class="tocxref"><span class="secno">6.2.2 </span>Number per Region</a></li></ul></li><li class="tocline"><a href="#div-element" class="tocxref"><span class="secno">6.3 </span><code>div</code> element</a></li><li class="tocline"><a href="#features-2" class="tocxref"><span class="secno">6.4 </span>Features</a></li></ul></li><li class="tocline"><a href="#hypothetical-render-model-1" class="tocxref"><span class="secno">7. </span>Hypothetical Render Model</a><ul class="toc"><li class="tocline"><a href="#performance-model" class="tocxref"><span class="secno">7.1 </span>Performance Model</a><ul class="toc"><li class="tocline"><a href="#overview" class="tocxref"><span class="secno">7.1.1 </span>Overview</a></li><li class="tocline"><a href="#general-2" class="tocxref"><span class="secno">7.1.2 </span>General</a></li><li class="tocline"><a href="#paint-regions" class="tocxref"><span class="secno">7.1.3 </span>Paint Regions</a></li><li class="tocline"><a href="#paint-images" class="tocxref"><span class="secno">7.1.4 </span>Paint Images</a></li><li class="tocline"><a href="#paint-text" class="tocxref"><span class="secno">7.1.5 </span>Paint Text</a></li></ul></li><li class="tocline"><a href="#layout-model" class="tocxref"><span class="secno">7.2 </span>Layout Model</a><ul class="toc"><li class="tocline"><a href="#general-3" class="tocxref"><span class="secno">7.2.1 </span>General</a></li><li class="tocline"><a href="#reference-fonts" class="tocxref"><span class="secno">7.2.2 </span>Reference Fonts</a></li><li class="tocline"><a href="#line-height-and-centering" class="tocxref"><span class="secno">7.2.3 </span>Line Height and Centering</a></li></ul></li></ul></li><li class="tocline"><a href="#recommended-character-sets-1" class="tocxref"><span class="secno">A. </span>Recommended Character Sets</a></li><li class="tocline"><a href="#schema" class="tocxref"><span class="secno">B. </span>Schema</a></li><li class="tocline"><a href="#references" class="tocxref"><span class="secno">C. </span>References</a><ul class="toc"><li class="tocline"><a href="#normative-references" class="tocxref"><span class="secno">C.1 </span>Normative references</a></li><li class="tocline"><a href="#informative-references" class="tocxref"><span class="secno">C.2 </span>Informative references</a></li></ul></li></ul></section>
+</section><section id="toc"><h2 class="introductory" aria-level="1" role="heading" id="h2_toc">Table of Contents</h2><ul class="toc" role="directory" id="respecContents"><li class="tocline"><a href="#scope" class="tocxref"><span class="secno">1. </span>Scope</a></li><li class="tocline"><a href="#conformance" class="tocxref"><span class="secno">2. </span>Conformance</a></li><li class="tocline"><a href="#profiles" class="tocxref"><span class="secno">3. </span>Profiles</a><ul class="toc"><li class="tocline"><a href="#general" class="tocxref"><span class="secno">3.1 </span>General</a></li><li class="tocline"><a href="#text-profile" class="tocxref"><span class="secno">3.2 </span>Text Profile</a></li><li class="tocline"><a href="#image-profile" class="tocxref"><span class="secno">3.3 </span>Image Profile</a></li></ul></li><li class="tocline"><a href="#common-constraints" class="tocxref"><span class="secno">4. </span>Common Constraints</a><ul class="toc"><li class="tocline"><a href="#document-encoding" class="tocxref"><span class="secno">4.1 </span>Document Encoding</a></li><li class="tocline"><a href="#namespaces" class="tocxref"><span class="secno">4.2 </span>Namespaces</a></li><li class="tocline"><a href="#related-video-object" class="tocxref"><span class="secno">4.3 </span>Related Video Object</a></li><li class="tocline"><a href="#synchronization" class="tocxref"><span class="secno">4.4 </span>Synchronization</a></li><li class="tocline"><a href="#extensions" class="tocxref"><span class="secno">4.5 </span>Extensions</a><ul class="toc"><li class="tocline"><a href="#ttp-aspectratio" class="tocxref"><span class="secno">4.5.1 </span>ttp:aspectRatio</a></li><li class="tocline"><a href="#ttp-progressivelydecodable" class="tocxref"><span class="secno">4.5.2 </span>ttp:progressivelyDecodable</a></li><li class="tocline"><a href="#tts-forceddisplay" class="tocxref"><span class="secno">4.5.3 </span>tts:forcedDisplay</a></li></ul></li><li class="tocline"><a href="#region" class="tocxref"><span class="secno">4.6 </span>Region</a><ul class="toc"><li class="tocline"><a href="#presented-region" class="tocxref"><span class="secno">4.6.1 </span>Presented Region</a></li><li class="tocline"><a href="#dimensions-and-position" class="tocxref"><span class="secno">4.6.2 </span>Dimensions and Position</a></li><li class="tocline"><a href="#maximum-number" class="tocxref"><span class="secno">4.6.3 </span>Maximum number</a></li></ul></li><li class="tocline"><a href="#hypothetical-render-model" class="tocxref"><span class="secno">4.7 </span>Hypothetical Render Model</a></li><li class="tocline"><a href="#features" class="tocxref"><span class="secno">4.8 </span>Features</a></li></ul></li><li class="tocline"><a href="#text-profile-constraints" class="tocxref"><span class="secno">5. </span>Text Profile Constraints</a><ul class="toc"><li class="tocline"><a href="#profile-designator" class="tocxref"><span class="secno">5.1 </span>Profile Designator</a></li><li class="tocline"><a href="#recommended-character-sets" class="tocxref"><span class="secno">5.2 </span>Recommended Character Sets</a></li><li class="tocline"><a href="#features-1" class="tocxref"><span class="secno">5.3 </span>Features</a></li></ul></li><li class="tocline"><a href="#image-profile-constraints" class="tocxref"><span class="secno">6. </span>Image Profile Constraints</a><ul class="toc"><li class="tocline"><a href="#profile-designator-1" class="tocxref"><span class="secno">6.1 </span>Profile Designator</a></li><li class="tocline"><a href="#presented-image" class="tocxref"><span class="secno">6.2 </span>Presented Image</a><ul class="toc"><li class="tocline"><a href="#definition" class="tocxref"><span class="secno">6.2.1 </span>Definition</a></li><li class="tocline"><a href="#number-per-region" class="tocxref"><span class="secno">6.2.2 </span>Number per Region</a></li></ul></li><li class="tocline"><a href="#div-element" class="tocxref"><span class="secno">6.3 </span><code>div</code> element</a></li><li class="tocline"><a href="#features-2" class="tocxref"><span class="secno">6.4 </span>Features</a></li></ul></li><li class="tocline"><a href="#hypothetical-render-model-1" class="tocxref"><span class="secno">7. </span>Hypothetical Render Model</a><ul class="toc"><li class="tocline"><a href="#performance-model" class="tocxref"><span class="secno">7.1 </span>Performance Model</a><ul class="toc"><li class="tocline"><a href="#overview" class="tocxref"><span class="secno">7.1.1 </span>Overview</a></li><li class="tocline"><a href="#general-1" class="tocxref"><span class="secno">7.1.2 </span>General</a></li><li class="tocline"><a href="#paint-regions" class="tocxref"><span class="secno">7.1.3 </span>Paint Regions</a></li><li class="tocline"><a href="#paint-images" class="tocxref"><span class="secno">7.1.4 </span>Paint Images</a></li><li class="tocline"><a href="#paint-text" class="tocxref"><span class="secno">7.1.5 </span>Paint Text</a></li></ul></li><li class="tocline"><a href="#reference-fonts" class="tocxref"><span class="secno">7.2 </span>Reference Fonts</a></li></ul></li><li class="tocline"><a href="#recommended-character-sets-1" class="tocxref"><span class="secno">A. </span>Recommended Character Sets</a></li><li class="tocline"><a href="#extensions-1" class="tocxref"><span class="secno">B. </span>Extensions</a><ul class="toc"><li class="tocline"><a href="#general-2" class="tocxref"><span class="secno">B.1 </span>General</a></li><li class="tocline"><a href="#progressivelydecodable" class="tocxref"><span class="secno">B.2 </span>#progressivelyDecodable</a></li><li class="tocline"><a href="#aspectratio" class="tocxref"><span class="secno">B.3 </span>#aspectRatio</a></li><li class="tocline"><a href="#forceddisplay" class="tocxref"><span class="secno">B.4 </span>#forcedDisplay</a></li><li class="tocline"><a href="#http-www.smpte-ra.org-schemas-2052-1-2010-smpte-tt-image" class="tocxref"><span class="secno">B.5 </span>http://www.smpte-ra.org/schemas/2052-1/2010/smpte-tt#image</a></li></ul></li><li class="tocline"><a href="#references" class="tocxref"><span class="secno">C. </span>References</a><ul class="toc"><li class="tocline"><a href="#normative-references" class="tocxref"><span class="secno">C.1 </span>Normative references</a></li><li class="tocline"><a href="#informative-references" class="tocxref"><span class="secno">C.2 </span>Informative references</a></li></ul></li></ul></section>
+
   
-      
-
-  <section id="scope" typeof="bibo:Chapter" resource="#ref" rel="bibo:Chapter">
+
+  <section id="scope" typeof="bibo:Chapter" resource="#scope" rel="bibo:Chapter">
     <!--OddPage--><h2 aria-level="1" role="heading" id="h2_scope"><span class="secno">1. </span>Scope</h2>
 
-    <p>This document specifies two profiles of [<cite><a class="bibref" href="#bib-TTML2">TTML2</a></cite>]: a text-only profile and an image-only profile. These profiles are
+    <p>This document specifies two profiles of [<cite><a class="bibref" href="#bib-TTML1">TTML1</a></cite>]: a text-only profile and an image-only profile. These profiles are
     intended for subtitle and caption delivery worldwide, including dialog language translation, content description, captions for
     deaf and hard of hearing, etc.</p>
-	
-	 <p>The profiles are strict subset of [<cite><a class="bibref" href="#bib-TTML2">TTML2</a></cite>] and the text-only profile a strict supersets of [<cite><a class="bibref" href="#bib-SDPUS">SDPUS</a></cite>].</p>
+
+    <p>The text-only profile is a strict superset of [<cite><a class="bibref" href="#bib-SDPUS">SDPUS</a></cite>] and the image-only profile uses extensions specified in
+    [<cite><a class="bibref" href="#bib-ST2052-1">ST2052-1</a></cite>].</p>
   </section>
 
-  <section id="conformance" typeof="bibo:Chapter" resource="#ref" rel="bibo:Chapter"><!--OddPage--><h2 aria-level="1" role="heading" id="h2_conformance"><span class="secno">2. </span>Conformance</h2>
+  <section id="conformance" typeof="bibo:Chapter" resource="#conformance" rel="bibo:Chapter"><!--OddPage--><h2 aria-level="1" role="heading" id="h2_conformance"><span class="secno">2. </span>Conformance</h2>
 <p>
   As well as sections marked as non-normative, all authoring guidelines, diagrams, examples,
   and notes in this specification are non-normative. Everything else in this specification is
@@ -429,6 +427,30 @@
 
             <td>http://www.w3.org/ns/ttml/profile/imsc</td>
           </tr>
+
+          <tr>
+            <td>ttp</td>
+
+            <td>http://www.w3.org/ns/ttml#parameter</td>
+          </tr>
+
+          <tr>
+            <td>tts</td>
+
+            <td>http://www.w3.org/ns/ttml#styling</td>
+          </tr>
+
+          <tr>
+            <td><em>none</em></td>
+
+            <td>http://www.w3.org/ns/ttml/feature/</td>
+          </tr>
+
+          <tr>
+            <td><em>none</em></td>
+
+            <td>http://www.w3.org/ns/ttml/extension/</td>
+          </tr>
         </tbody>
       </table>
 
@@ -439,18 +461,36 @@
     <section id="related-video-object">
       <h3 aria-level="2" role="heading" id="h3_related-video-object"><span class="secno">4.3 </span>Related Video Object</h3>
 
-      <section id="general-1">
-        <h4 aria-level="3" role="heading" id="h4_general-1"><span class="secno">4.3.1 </span>General</h4>
-
-        <p>A subtitle document <em class="rfc2119" title="MAY">MAY</em> be associated with a related video object, which <em class="rfc2119" title="SHALL">SHALL</em> consist of a sequence of frames, each a
-        rectangular array of pixels.</p>
-      </section>
-
-      <section id="root-container">
-        <h4 aria-level="3" role="heading" id="h4_root-container"><span class="secno">4.3.2 </span>Root Container</h4>
-
-        <div class="issue"><div class="issue-title" aria-level="4" role="heading" id="h_issue_1"><span>Issue 1</span></div><p class="">See <a href="http://www.w3.org/AudioVideo/TT/tracker/issues/201">ISSUE-201</a> for a discussion of aspect
-        ratio in the context of [<cite><a class="bibref" href="#bib-TTML2">TTML2</a></cite>].</p></div>
+      <p>A subtitle document <em class="rfc2119" title="MAY">MAY</em> be associated with a related video object, which <em class="rfc2119" title="SHALL">SHALL</em> consist of a sequence of frames, each a
+      rectangular array of pixels.</p>
+    </section>
+
+    <section id="synchronization">
+      <h3 aria-level="2" role="heading" id="h3_synchronization"><span class="secno">4.4 </span>Synchronization</h3>
+
+      <p>Each intermediate synchronic document of the subtitle document is intended to be displayed on a specific frame and removed
+      on a specific frame of the related video object.</p>
+
+      <p>A media time expression M <em class="rfc2119" title="SHALL">SHALL</em> correspond to the frame of the related video object with the presentation time that is the
+      closest to, but not less, than M.</p>
+
+      <p>If <code>ttp:frameRate</code> is specified, then the product of <code>ttp:frameRate</code> and
+      <code>ttp:frameRateMultiplier</code> <em class="rfc2119" title="SHALL">SHALL</em> be the frame rate of the related video object.</p>
+
+      <aside class="example"><div class="example-title"><span>Example 1</span></div>
+        A media time expression of 00:00:05.1 corresponds to frame ceiling(5.1 × ( 1000 / 1001 × 30) = 153 of a related video
+        object with a frame rate of 1000 / 1001 × 30 ≈ 29.97.
+      </aside>
+    </section>
+
+    <section id="extensions">
+      <h3 aria-level="2" role="heading" id="h3_extensions"><span class="secno">4.5 </span>Extensions</h3>
+
+      <section id="ttp-aspectratio">
+        <h4 aria-level="3" role="heading" id="h4_ttp-aspectratio"><span class="secno">4.5.1 </span>ttp:aspectRatio</h4>
+
+        <p>The <code>ttp:aspectRatio</code> attributes allows authorial control of the mapping of the root container of a subtitle
+        document to the related video object frame.</p>
 
         <p>The root container of a subtitle document <em class="rfc2119" title="SHALL">SHALL</em> be mapped to the related video object frame according to the
         following:</p>
@@ -465,7 +505,8 @@
 
               <li>the center of the rectangular area is colocated with the center of the related video object frame,</li>
 
-              <li>the rectangular area (including its boundary) is entirely within the related video object frame (including its boundary), and</li>
+              <li>the rectangular area (including its boundary) is entirely within the related video object frame (including its
+              boundary), and</li>
 
               <li>the rectangular area has a height or width equal to that of the related video object frame.</li>
             </ol>
@@ -480,84 +521,124 @@
 
         <p><code>ttp:aspectRatio</code> <em class="rfc2119" title="SHALL NOT">SHALL NOT</em> be present if <code>tts:extent</code> is present.<br></p>
 
-        <div class="note"><div class="note-title" aria-level="4" role="heading" id="h_note_1"><span>Note</span></div><p class="">As specified in Section <a href="#features" class="sec-ref"><span class="secno">4.7</span> <span class="sec-title">Features</span></a>, <code>tts:extent</code> is present if the <code>px</code>
+        <div class="note"><div class="note-title" aria-level="4" role="heading" id="h_note_1"><span>Note</span></div><p class="">As specified in Section <a href="#features" class="sec-ref"><span class="secno">4.8</span> <span class="sec-title">Features</span></a>, <code>tts:extent</code> is present if the <code>px</code>
         length measure is used anywhere within the document.</p></div>
 
         <p>Integer pixel positions on the related video object frame computed from real percentage length values <em class="rfc2119" title="SHALL">SHALL</em> use half-up
         rounding, i.e. round(x) = floor(x+0.5).</p>
       </section>
 
-      <section id="synchronization">
-        <h4 aria-level="3" role="heading" id="h4_synchronization"><span class="secno">4.3.3 </span>Synchronization</h4>
-
-        <p>Each intermediate synchronic document of the subtitle document is intended to be displayed on a specific frame and
-        removed on a specific frame of the related video object.</p>
-
-        <p>A media time expression M <em class="rfc2119" title="SHALL">SHALL</em> correspond to the frame of the related video object with the presentation time that is
-        the closest to, but not less, than M.</p>
-
-        <p>If <code>ttp:frameRate</code> is specified, then the product of <code>ttp:frameRate</code> and
-        <code>ttp:frameRateMultiplier</code> <em class="rfc2119" title="SHALL">SHALL</em> be the frame rate of the related video object.</p>
-
-        <aside class="example"><div class="example-title"><span>Example 1</span></div>
-          A media time expression of 00:00:05.1 corresponds to frame ceiling(5.1 × ( 1000 / 1001 × 30) = 153 of a related video
-          object with a frame rate of 1000 / 1001 × 30 ≈ 29.97.
-        </aside>
-      </section>
-    </section>
-
-    <section id="progressively-decodable">
-      <h3 aria-level="2" role="heading" id="h3_progressively-decodable"><span class="secno">4.4 </span>Progressively Decodable</h3>
-
-      <p>A progressively decodable subtitle document is a subtitle document structured to facilitate processing before the document
-      is received in its entirety. It shall conform to the following:</p>
-
-      <ol>
-        <li>elements appear in the document in increasing order according to their resolved begin time;</li>
-
-        <li>no element references another element (i) occurring later in the document or (ii) with a later begin time; and</li>
-
-        <li>a <code>imsc:progressivelyDecodable</code> attribute with value "true" is present on the <code>tt</code>
-        element.</li>
-      </ol>
-
-      <p>The <code>imsc:progressivelyDecodable</code> attribute shall conform to the following syntax:</p>
-
-      <table class="syntax">
-        <tbody>
-          <tr>
-            <td>
-              <div class="exampleInner">
-                <pre>imsc:progressivelyDecodable
+      <section id="ttp-progressivelydecodable">
+        <h4 aria-level="3" role="heading" id="h4_ttp-progressivelydecodable"><span class="secno">4.5.2 </span>ttp:progressivelyDecodable</h4>
+
+        <p>A progressively decodable subtitle document is a subtitle document structured to facilitate processing before the
+        document is received in its entirety. It shall conform to the following:</p>
+
+        <ol>
+          <li>elements appear in the document in increasing order according to their resolved begin time;</li>
+
+          <li>no element references another element (i) occurring later in the document or (ii) with a later begin time; and</li>
+
+          <li>a <code>ttp:progressivelyDecodable</code> attribute with value "true" is present on the <code>tt</code>
+          element.</li>
+        </ol>
+
+        <p>The <code>ttp:progressivelyDecodable</code> attribute shall conform to the following syntax:</p>
+
+        <table class="syntax">
+          <tbody>
+            <tr>
+              <td>
+                <div class="exampleInner">
+                  <pre>imsc:progressivelyDecodable
   : "true"
   | "false"
 </pre>
-              </div>
-            </td>
-          </tr>
-        </tbody>
-      </table>
-
-      <p>The initial value of <code>imsc:progressivelyDecodable</code> shall be "false".</p>
-
-      <p>A <code>imsc:progressivelyDecodable</code> attribute with value "false" may be present on the <code>tt</code>
-      element if the subtitle document is not a progressively decodable subtitle document.</p>
-
-      <p>A <code>imsc:progressivelyDecodable</code> attribute is considered to be significant only when specified on the
-      <code>tt</code> element.</p>
-
-      <div class="note"><div class="note-title" aria-level="3" role="heading" id="h_note_2"><span>Note</span></div><p class="">The placement and use of <code>div</code>, <code>region</code> and <code>span</code> that contain time
-      attributes, and (ii) the use of <code>set</code>.</p></div>
+                </div>
+              </td>
+            </tr>
+          </tbody>
+        </table>
+
+        <p>The initial value of <code>ttp:progressivelyDecodable</code> shall be "false".</p>
+
+        <p>A <code>ttp:progressivelyDecodable</code> attribute with value "false" may be present on the <code>tt</code>
+        element if the subtitle document is not a progressively decodable subtitle document.</p>
+
+        <p>A <code>ttp:progressivelyDecodable</code> attribute is considered to be significant only when specified on the
+        <code>tt</code> element.</p>
+
+        <div class="note"><div class="note-title" aria-level="4" role="heading" id="h_note_2"><span>Note</span></div><p class="">The placement and use of <code>div</code>, <code>region</code> and <code>span</code> that contain time
+        attributes, and (ii) the use of <code>set</code>.</p></div>
+      </section>
+
+      <section id="tts-forceddisplay">
+        <h4 aria-level="3" role="heading" id="h4_tts-forceddisplay"><span class="secno">4.5.3 </span>tts:forcedDisplay</h4>
+
+        <p>The tts:forcedDisplay signals that a block of subtitle content is identified as <em>Forced</em> subtitle content.
+        <em>Forced</em> subtitle content is subtitle content that represents audio (e.g. foreign language) or text (e.g. a sign)
+        that is not translated in the audio/video presentation.</p>
+
+        <table class="simple">
+          <colgroup>
+            <col width="25%" span="1">
+            <col span="1">
+          </colgroup>
+
+          <tbody>
+            <tr>
+              <td><em>Values:</em></td>
+
+              <td><code>false | true</code></td>
+            </tr>
+
+            <tr>
+              <td><em>Initial:</em></td>
+
+              <td><code>false</code></td>
+            </tr>
+
+            <tr>
+              <td><em>Applies to:</em></td>
+
+              <td><code>body</code>, <code>div</code>, <code>p</code>, <code>region</code>, <code>span</code></td>
+            </tr>
+
+            <tr>
+              <td><em>Inherited:</em></td>
+
+              <td>yes</td>
+            </tr>
+
+            <tr>
+              <td><em>Percentages:</em></td>
+
+              <td>N/A</td>
+            </tr>
+
+            <tr>
+              <td><em>Animatable:</em></td>
+
+              <td>discrete</td>
+            </tr>
+          </tbody>
+        </table>
+
+        <div class="note"><div class="note-title" aria-level="4" role="heading" id="h_note_3"><span>Note</span></div><p class="">Although <code>tts:forcedDisplay</code>, like all the TTML style attributes, has no defined semantics on a
+        <code>br</code> content element, forcedDisplayMode will apply to a <code>br</code> content element if it is either defined
+        on an ancestor content element of the <code>br</code> content element or it is applied to a region element corresponding to
+        a region that the <code>br</code> content element is being flowed into.</p></div>
+      </section>
     </section>
 
     <section id="region">
-      <h3 aria-level="2" role="heading" id="h3_region"><span class="secno">4.5 </span>Region</h3>
+      <h3 aria-level="2" role="heading" id="h3_region"><span class="secno">4.6 </span>Region</h3>
 
       <section id="presented-region">
-        <h4 aria-level="3" role="heading" id="h4_presented-region"><span class="secno">4.5.1 </span>Presented Region</h4>
-
-        <p>A region, as defined in [<cite><a class="bibref" href="#bib-TTML2">TTML2</a></cite>], is presented in a given intermediate synchronic document if all of
-        the following conditions are true:</p>
+        <h4 aria-level="3" role="heading" id="h4_presented-region"><span class="secno">4.6.1 </span>Presented Region</h4>
+
+        <p>A region, as defined in [<cite><a class="bibref" href="#bib-TTML1">TTML1</a></cite>], is presented in a given intermediate synchronic document if all of the following
+        conditions are true:</p>
 
         <ol>
           <li>
@@ -574,48 +655,49 @@
           </li>
         </ol>
 
-        <div class="note"><div class="note-title" aria-level="4" role="heading" id="h_note_3"><span>Note</span></div><p class="">As specified in [<cite><a class="bibref" href="#bib-TTML2">TTML2</a></cite>], the initial value of <code>tts:opacity</code> is "1.0", the initial
+        <div class="note"><div class="note-title" aria-level="4" role="heading" id="h_note_4"><span>Note</span></div><p class="">As specified in [<cite><a class="bibref" href="#bib-TTML1">TTML1</a></cite>], the initial value of <code>tts:opacity</code> is "1.0", the initial
         value of <code>tts:showBackground</code> is "always", and the initial value of <code>tts:display</code> is
         "auto"</p></div>
       </section>
 
       <section id="dimensions-and-position">
-        <h4 aria-level="3" role="heading" id="h4_dimensions-and-position"><span class="secno">4.5.2 </span>Dimensions and Position</h4>
-
-        <p>All regions <em class="rfc2119" title="SHALL NOT">SHALL NOT</em> extend beyond the root container, i.e. the intersection of the sets of coordinates belonging to a region (including its boundary) and the sets of coordinates belonging to the root container (including its boundary) is the set of coordinates belonging to the region (including its boundary).</p>
-
-        <p>No two presented regions in a given intermediate synchronic document <em class="rfc2119" title="SHALL">SHALL</em> overlap, i.e. the intersection of the sets of coordinates within each region (including its boundary) is empty.</p>
+        <h4 aria-level="3" role="heading" id="h4_dimensions-and-position"><span class="secno">4.6.2 </span>Dimensions and Position</h4>
+
+        <p>All regions <em class="rfc2119" title="SHALL NOT">SHALL NOT</em> extend beyond the root container, i.e. the intersection of the sets of coordinates belonging to a
+        region (including its boundary) and the sets of coordinates belonging to the root container (including its boundary) is the
+        set of coordinates belonging to the region (including its boundary).</p>
+
+        <p>No two presented regions in a given intermediate synchronic document <em class="rfc2119" title="SHALL">SHALL</em> overlap, i.e. the intersection of the sets of
+        coordinates within each region (including its boundary) is empty.</p>
       </section>
 
       <section id="maximum-number">
-        <h4 aria-level="3" role="heading" id="h4_maximum-number"><span class="secno">4.5.3 </span>Maximum number</h4>
+        <h4 aria-level="3" role="heading" id="h4_maximum-number"><span class="secno">4.6.3 </span>Maximum number</h4>
 
         <p>The number of presented regions in a given intermediate synchronic document <em class="rfc2119" title="SHALL NOT">SHALL NOT</em> be greater than 4.</p>
       </section>
     </section>
 
     <section id="hypothetical-render-model">
-      <h3 aria-level="2" role="heading" id="h3_hypothetical-render-model"><span class="secno">4.6 </span>Hypothetical Render Model</h3>
+      <h3 aria-level="2" role="heading" id="h3_hypothetical-render-model"><span class="secno">4.7 </span>Hypothetical Render Model</h3>
 
       <p>Any sequence of consecutive intermediate synchronic documents <em class="rfc2119" title="SHALL">SHALL</em> be reproducible without error by the Hypothetical
       Render Model specified in Section <a href="#h2_hypothetical-render-model-1"></a>.</p>
     </section>
 
     <section id="features">
-      <h3 aria-level="2" role="heading" id="h3_features"><span class="secno">4.7 </span>Features</h3>
-	  
-	  <p>Unless specified otherwise, the features included in a subtitle document <em class="rfc2119" title="SHALL">SHALL</em> conform to the Table below:</p>
+      <h3 aria-level="2" role="heading" id="h3_features"><span class="secno">4.8 </span>Features</h3>
+
+      <p>Unless specified otherwise,a subtitle document <em class="rfc2119" title="SHALL">SHALL</em> conform to the following:</p>
 
       <table class="simple">
-        <thead>
+        <tbody>
           <tr>
             <th>Feature</th>
 
             <th>Provisions</th>
           </tr>
-        </thead>
-
-        <tbody>
+
           <tr>
             <td><code>#animation</code></td>
 
@@ -1006,23 +1088,32 @@
           </tr>
 
           <tr>
-            <td><code>#aspectRatio</code></td>
+            <th>Extension</th>
+
+            <th>Provisions</th>
+          </tr>
+
+          <tr>
+            <td><code>http://www.w3.org/ns/ttml/extension/#aspectRatio</code></td>
 
             <td><em class="rfc2119" title="MAY">MAY</em> be used.</td>
           </tr>
 
           <tr>
-            <td><code>#forcedDisplay</code></td>
+            <td><code>http://www.w3.org/ns/ttml/extension/#forcedDisplay</code></td>
+
+            <td><em class="rfc2119" title="MAY">MAY</em> be used.</td>
+          </tr>
+
+          <tr>
+            <td><code>http://www.w3.org/ns/ttml/extension/#progressivelyDecodable</code></td>
 
             <td><em class="rfc2119" title="MAY">MAY</em> be used.</td>
           </tr>
         </tbody>
       </table>
 
-      <div class="issue"><div class="issue-title" aria-level="3" role="heading" id="h_issue_2"><span>Issue 2</span></div><p class="">See <a href="http://www.w3.org/AudioVideo/TT/tracker/issues/230">ISSUE-230</a> for a description of
-      <code>#forcedDisplay</code></p></div>
-
-      <div class="note"><div class="note-title" aria-level="3" role="heading" id="h_note_4"><span>Note</span></div><p class="">As specified in [<cite><a class="bibref" href="#bib-TTML2">TTML2</a></cite>], a <code>#time-offset-with-frames</code> expression is translated to a media time
+      <div class="note"><div class="note-title" aria-level="3" role="heading" id="h_note_5"><span>Note</span></div><p class="">As specified in [<cite><a class="bibref" href="#bib-TTML1">TTML1</a></cite>], a <code>#time-offset-with-frames</code> expression is translated to a media time
       M according to M = 3600 · hours + 60 · minutes + seconds + (frames ÷ (<code>ttp:frameRateMultiplier</code> ·
       <code>ttp:frameRate</code>)).</p></div>
     </section>
@@ -1031,44 +1122,47 @@
   <section id="text-profile-constraints">
     <!--OddPage--><h2 aria-level="1" role="heading" id="h2_text-profile-constraints"><span class="secno">5. </span>Text Profile Constraints</h2>
 
-    <section id="profile-designator-and-definition-document">
-      <h3 aria-level="2" role="heading" id="h3_profile-designator-and-definition-document"><span class="secno">5.1 </span>Profile Designator and Definition Document</h3>
-	  
-	    <div class="issue"><div class="issue-title" aria-level="3" role="heading" id="h_issue_3"><span>Issue 3</span></div><p class="">This Section is a placeholder and will be revisited based the outcome of the [<cite><a class="bibref" href="#bib-TTML2">TTML2</a></cite>] profile discussions.</p></div>
-
-      <p>A subtitle document conforming to the Text Profile <em class="rfc2119" title="SHALL">SHALL</em> be associated with the following profile designator and profile
-      definition document:</p>
-      <pre>&lt;?xml version="1.0" encoding="utf-8"?&gt;
-&lt;profile designator="http://www.w3.org/ns/ttml/profile/imsc/text/designator" xmlns="http://www.w3.org/ns/ttml#parameter"&gt;
-  &lt;extensions&gt;
-    &lt;extension&gt;http://www.w3.org/ns/ttml/profile/imsc/text/feature#all&lt;/extension&gt;
-  &lt;/extensions&gt;
-&lt;/profile&gt;
-</pre>
-    </section>
-<section id="recommended-character-sets">
-      <h3 aria-level="2" role="heading" id="h3_recommended-character-sets"><span class="secno">5.2 </span>Recommended Character Sets</h3>
-	
-	<p></p>Authors should to select from the sets of characters specified in <a href="#recommended-character-sets-1" class="sec-ref"><span class="secno">A.</span> <span class="sec-title">Recommended Character Sets</span></a><p></p>
-	  </section>
-    <section id="features-1">
-      <h3 aria-level="2" role="heading" id="h3_features-1"><span class="secno">5.3 </span>Features</h3>
-		
-      <div class="issue"><div class="issue-title" aria-level="3" role="heading" id="h_issue_4"><span>Issue 4</span></div><p class="">The following assumes, but does not require, the porting of the [<cite><a class="bibref" href="#bib-ST2052-1">ST2052-1</a></cite>] <code>#backgroundImage</code>
-      features to [<cite><a class="bibref" href="#bib-TTML2">TTML2</a></cite>]. See <a href="http://www.w3.org/AudioVideo/TT/tracker/issues/238">ISSUE-238</a>.</p></div>
-	  
-	  <p>The features included in a subtitle document <em class="rfc2119" title="SHALL">SHALL</em> conform to the Table below:</p>
+    <section id="profile-designator">
+      <h3 aria-level="2" role="heading" id="h3_profile-designator"><span class="secno">5.1 </span>Profile Designator</h3>
+
+      <p>A subtitle document conforming to the Text Profile <em class="rfc2119" title="SHALL">SHALL</em> be associated with the following profile designator:</p>
 
       <table class="simple">
         <thead>
           <tr>
+            <th>Profile Name</th>
+
+            <th>Profile Designator</th>
+          </tr>
+        </thead>
+
+        <tbody>
+          <tr>
+            <td>IMSC Text</td>
+
+            <td><code>http://www.w3.org/ns/ttml/profile/imsc/text</code></td>
+          </tr>
+        </tbody>
+      </table>
+    </section>
+
+    <section id="recommended-character-sets">
+      <h3 aria-level="2" role="heading" id="h3_recommended-character-sets"><span class="secno">5.2 </span>Recommended Character Sets</h3>Authors should to select from the sets of characters specified in <a href="#recommended-character-sets-1" class="sec-ref"><span class="secno">A.</span> <span class="sec-title">Recommended Character Sets</span></a>
+    </section>
+
+    <section id="features-1">
+      <h3 aria-level="2" role="heading" id="h3_features-1"><span class="secno">5.3 </span>Features</h3>
+
+      <p>The subtitle document <em class="rfc2119" title="SHALL">SHALL</em> conform to the following:</p>
+
+      <table class="simple">
+        <tbody>
+          <tr>
             <th>Feature</th>
 
             <th>Provisions</th>
           </tr>
-        </thead>
-
-        <tbody>
+
           <tr>
             <td><code>#backgroundColor-block</code></td>
 
@@ -1094,24 +1188,6 @@
           </tr>
 
           <tr>
-            <td><code>#backgroundImage</code></td>
-
-            <td><em class="rfc2119" title="SHALL NOT">SHALL NOT</em> be used.</td>
-          </tr>
-
-          <tr>
-            <td><code>#backgroundImageHorizontal</code></td>
-
-            <td><em class="rfc2119" title="SHALL NOT">SHALL NOT</em> be used.</td>
-          </tr>
-
-          <tr>
-            <td><code>#backgroundImageVertical</code></td>
-
-            <td><em class="rfc2119" title="SHALL NOT">SHALL NOT</em> be used.</td>
-          </tr>
-
-          <tr>
             <td><code>#bidi</code></td>
 
             <td><em class="rfc2119" title="MAY">MAY</em> be used.</td>
@@ -1120,7 +1196,8 @@
           <tr>
             <td><code>#color</code></td>
 
-            <td><em class="rfc2119" title="MAY">MAY</em> be used. The initial value of <code>tts:color</code> <em class="rfc2119" title="SHALL">SHALL</em> be "white".</td>
+            <td><em class="rfc2119" title="MAY">MAY</em> be used. The initial value of <code>tts:color</code> <em class="rfc2119" title="SHALL">SHALL</em> be "white". NOTE: This is consistent with
+            [<cite><a class="bibref" href="#bib-ST2052-1">ST2052-1</a></cite>].</td>
           </tr>
 
           <tr>
@@ -1132,17 +1209,15 @@
           <tr>
             <td><code>#displayAlign</code></td>
 
-            <td><em class="rfc2119" title="MAY">MAY</em> be used. The initial value of <code>tts:displayAlign</code> <em class="rfc2119" title="SHALL">SHALL</em> be "after" for the default region, as defined in [<cite><a class="bibref" href="#bib-TTML2">TTML2</a></cite>].</td>
+            <td><em class="rfc2119" title="MAY">MAY</em> be used. The initial value of <code>tts:displayAlign</code> <em class="rfc2119" title="SHALL">SHALL</em> be "after" for the default region.
+            NOTE: This is consistent with [<cite><a class="bibref" href="#bib-ST2052-1">ST2052-1</a></cite>].</td>
           </tr>
 
           <tr>
             <td><code>#extent-region</code></td>
 
-            <td>
-              The <code>tts:extent</code> attribute when applied to a region element <em class="rfc2119" title="SHALL">SHALL</em> use <code>px</code> units or
-              "percentage" representation, and <em class="rfc2119" title="SHALL NOT">SHALL NOT</em> use <code>em</code> units.<br>
-              Section <a href="#layout-model" class="sec-ref"><span class="secno">7.2</span> <span class="sec-title">Layout Model</span></a> <em class="rfc2119" title="SHOULD">SHOULD</em> be used to calculate a region extent that avoids clipping.
-            </td>
+            <td>The <code>tts:extent</code> attribute when applied to a region element <em class="rfc2119" title="SHALL">SHALL</em> use <code>px</code> units or
+            "percentage" representation, and <em class="rfc2119" title="SHALL NOT">SHALL NOT</em> use <code>em</code> units.<br></td>
           </tr>
 
           <tr>
@@ -1234,7 +1309,9 @@
           <tr>
             <td><code>#lineHeight</code></td>
 
-            <td><em class="rfc2119" title="MAY">MAY</em> be used.</td>
+            <td><em class="rfc2119" title="MAY">MAY</em> be used.<br>
+            An explicit <code>&lt;length&gt;</code> <em class="rfc2119" title="SHOULD">SHOULD</em> be specified as there is no uniform implementation of the
+            "normal" value at the time of this writing.</td>
           </tr>
 
           <tr>
@@ -1301,7 +1378,8 @@
           <tr>
             <td><code>#textAlign</code></td>
 
-            <td><em class="rfc2119" title="MAY">MAY</em> be used. The initial value of <code>tts:textAlign</code> <em class="rfc2119" title="SHALL">SHALL</em> be "center" for the default region, as defined in [<cite><a class="bibref" href="#bib-TTML2">TTML2</a></cite>].</td>
+            <td><em class="rfc2119" title="MAY">MAY</em> be used. The initial value of <code>tts:textAlign</code> <em class="rfc2119" title="SHALL">SHALL</em> be "center" for the default region.
+            NOTE: This is consistent with [<cite><a class="bibref" href="#bib-ST2052-1">ST2052-1</a></cite>].</td>
           </tr>
 
           <tr>
@@ -1357,30 +1435,46 @@
 
             <td><em class="rfc2119" title="MAY">MAY</em> be used.</td>
           </tr>
+
+          <tr>
+            <th>Extension</th>
+
+            <th>Provisions</th>
+          </tr>
+
+          <tr>
+            <td><code>http://www.smpte-ra.org/schemas/2052-1/2010/smpte-tt#image</code></td>
+
+            <td><em class="rfc2119" title="SHALL NOT">SHALL NOT</em> be used.</td>
+          </tr>
         </tbody>
       </table>
-	  
-	        <div class="note"><div class="note-title" aria-level="3" role="heading" id="h_note_5"><span>Note</span></div><p class="">The initial values specified for <code>tts:color</code>, <code>tts:displayAlign</code> are those specified by [<cite><a class="bibref" href="#bib-ST2052-1">ST2052-1</a></cite>].</p></div>
     </section>
   </section>
 
   <section id="image-profile-constraints">
     <!--OddPage--><h2 aria-level="1" role="heading" id="h2_image-profile-constraints"><span class="secno">6. </span>Image Profile Constraints</h2>
 
-    <section id="profile-designator-and-definition-document-1">
-      <h3 aria-level="2" role="heading" id="h3_profile-designator-and-definition-document-1"><span class="secno">6.1 </span>Profile Designator and Definition Document</h3>
-	  
-	  	    <div class="issue"><div class="issue-title" aria-level="3" role="heading" id="h_issue_5"><span>Issue 5</span></div><p class="">This Section is a placeholder and will be revisited based the outcome of the [<cite><a class="bibref" href="#bib-TTML2">TTML2</a></cite>] profile discussions.</p></div>
-
-      <p>A subtitle document conforming to the Image Profile <em class="rfc2119" title="SHALL">SHALL</em> be associated with the following profile designator and profile
-      definition document:</p>
-      <pre>&lt;?xml version="1.0" encoding="utf-8"?&gt;
-&lt;profile designator="http://www.w3.org/ns/ttml/profile/imsc/image/designator" xmlns="http://www.w3.org/ns/ttml#parameter"&gt;
-  &lt;extensions&gt;
-    &lt;extension&gt;http://www.w3.org/ns/ttml/profile/definition/imsc/image/feature#all&lt;/extension&gt;
-  &lt;/extensions&gt;
-&lt;/profile&gt;
-</pre>
+    <section id="profile-designator-1">
+      <h3 aria-level="2" role="heading" id="h3_profile-designator-1"><span class="secno">6.1 </span>Profile Designator</h3>
+
+      <p>A subtitle document conforming to the Image Profile <em class="rfc2119" title="SHALL">SHALL</em> be associated with the following profile designator:</p>
+
+      <table class="simple">
+        <tbody>
+          <tr>
+            <th>Profile Name</th>
+
+            <th>Profile Designator</th>
+          </tr>
+
+          <tr>
+            <td>IMSC Image</td>
+
+            <td><code>http://www.w3.org/ns/ttml/profile/imsc/image</code></td>
+          </tr>
+        </tbody>
+      </table>
     </section>
 
     <section id="presented-image">
@@ -1405,49 +1499,22 @@
       <h3 aria-level="2" role="heading" id="h3_div-element"><span class="secno">6.3 </span><code>div</code> element</h3>
 
       <p>If a <code>tts:backgroundImage</code> attribute is applied to a <code>div</code> element, the width and height of the
-      region extent associated with the <code>div</code> element <em class="rfc2119" title="SHALL">SHALL</em> be specified and <em class="rfc2119" title="SHALL">SHALL</em> be equal to the width and height of the
-      image source referenced by the <code>tts:backgroundImage</code>.</p>
+      region extent associated with the <code>div</code> element <em class="rfc2119" title="SHALL">SHALL</em> be specified and <em class="rfc2119" title="SHALL">SHALL</em> be equal to the width and height of
+      the image source referenced by the <code>tts:backgroundImage</code>.</p>
     </section>
 
     <section id="features-2">
       <h3 aria-level="2" role="heading" id="h3_features-2"><span class="secno">6.4 </span>Features</h3>
 
-      <div class="issue"><div class="issue-title" aria-level="3" role="heading" id="h_issue_6"><span>Issue 6</span></div><p class="">The following assumes, but does not require, the porting of the [<cite><a class="bibref" href="#bib-ST2052-1">ST2052-1</a></cite>] <code>#backgroundImage</code>
-      features to [<cite><a class="bibref" href="#bib-TTML2">TTML2</a></cite>]. See <a href="http://www.w3.org/AudioVideo/TT/tracker/issues/238">ISSUE-238</a>.</p></div>
-
-	  
-	   <p>The features included in a subtitle document <em class="rfc2119" title="SHALL">SHALL</em> conform to the Table below:</p>
+      <p>The features included in a subtitle document <em class="rfc2119" title="SHALL">SHALL</em> conform to the Table below:</p>
 
       <table class="simple">
-        <thead>
+        <tbody>
           <tr>
             <th>Feature</th>
 
             <th>Provisions</th>
           </tr>
-        </thead>
-
-        <tbody>
-          <tr>
-            <td><code>#backgroundImage</code></td>
-
-            <td><em class="rfc2119" title="MAY">MAY</em> be used. The backgroundImage attribute <em class="rfc2119" title="SHALL">SHALL</em> reference a complete image that conforms to the PNG image coding
-            as specified in Sections 7.1.1.3 and 15.1 of [<cite><a class="bibref" href="#bib-MHP">MHP</a></cite>].<br>
-            If a pHYs chunk is present, it <em class="rfc2119" title="SHALL">SHALL</em> indicate square pixels. Note: If no pixel aspect ratio is carried, the default of
-            square pixels will be assumed.</td>
-          </tr>
-
-          <tr>
-            <td><code>#backgroundImageHorizontal</code></td>
-
-            <td><em class="rfc2119" title="SHALL NOT">SHALL NOT</em> be used. <code>#backgroundImage</code> remains available for use.</td>
-          </tr>
-
-          <tr>
-            <td><code>#backgroundImageVertical</code></td>
-
-            <td><em class="rfc2119" title="SHALL NOT">SHALL NOT</em> be used. <code>#backgroundImage</code> remains available for use.</td>
-          </tr>
 
           <tr>
             <td><code>#bidi</code></td>
@@ -1574,6 +1641,22 @@
 
             <td><em class="rfc2119" title="SHALL NOT">SHALL NOT</em> be used.</td>
           </tr>
+
+          <tr>
+            <th>Extension</th>
+
+            <th>Provisions</th>
+          </tr>
+
+          <tr>
+            <td><code>http://www.smpte-ra.org/schemas/2052-1/2010/smpte-tt#image</code></td>
+
+            <td><code>smpte:backgroundImage</code> <em class="rfc2119" title="MAY">MAY</em> be used. The backgroundImage attribute <em class="rfc2119" title="SHALL">SHALL</em> reference a complete image that
+            conforms to the PNG image coding as specified in Sections 7.1.1.3 and 15.1 of [<cite><a class="bibref" href="#bib-MHP">MHP</a></cite>]. If a pHYs chunk is present, it
+            <em class="rfc2119" title="SHALL">SHALL</em> indicate square pixels. Note: If no pixel aspect ratio is carried, the default of square pixels is assumed.<br>
+            <code>smpte:backgroundImageHorizontal</code> and <code>smpte:backgroundImageVertical</code> <em class="rfc2119" title="SHALL NOT">SHALL NOT</em> be used.<br>
+            <code>smpte:image</code> <em class="rfc2119" title="SHALL NOT">SHALL NOT</em> be used.</td>
+          </tr>
         </tbody>
       </table>
     </section>
@@ -1627,8 +1710,8 @@
         documents, allowing images to be copied into the Presentation Buffer instead of decoded.</p>
       </section>
 
-      <section id="general-2">
-        <h4 aria-level="3" role="heading" id="h4_general-2"><span class="secno">7.1.2 </span>General</h4>
+      <section id="general-1">
+        <h4 aria-level="3" role="heading" id="h4_general-1"><span class="secno">7.1.2 </span>General</h4>
 
         <p>The Presentation Compositor <em class="rfc2119" title="SHALL">SHALL</em> render in Presentation Buffer P<sub>n</sub> each successive intermediate synchronic
         document E<sub>n</sub> using the following steps in order:</p>
@@ -1737,7 +1820,7 @@
         <p>PAINT(E<sub>n</sub>) = ∑<sub>R<sub>i</sub>∈R<sub>p</sub></sub> SIZE(R<sub>i</sub>) ∙ NBG(R<sub>i</sub>)</p>
 
         <p>where R_p <em class="rfc2119" title="SHALL">SHALL</em> be the set of regions presented in the intermediate synchronic document E<sub>n</sub> – see Section
-        <a href="#presented-region" class="sec-ref"><span class="secno">4.5.1</span> <span class="sec-title">Presented Region</span></a> for the definition of presented region.</p>
+        <a href="#presented-region" class="sec-ref"><span class="secno">4.6.1</span> <span class="sec-title">Presented Region</span></a> for the definition of presented region.</p>
 
         <p>NSIZE(R<sub>i</sub>) <em class="rfc2119" title="SHALL">SHALL</em> be given by:</p>
 
@@ -1758,11 +1841,11 @@
           <li>It is specified on the <code>region</code> layout element that defines the region.</li>
 
           <li>It is specified on a <code>div</code>, <code>p</code>, <code>span</code> or <code>br</code> content element that is
-          to be flowed into the region for presentation in the intermediate synchronic document (see [<cite><a class="bibref" href="#bib-TTML2">TTML2</a></cite>] for more details on
+          to be flowed into the region for presentation in the intermediate synchronic document (see [<cite><a class="bibref" href="#bib-TTML1">TTML1</a></cite>] for more details on
           when a content element is followed into a region).</li>
 
           <li>It is specified on a <code>set</code> animation element that is to be applied to content elements that are to be
-          flowed into the region for presentation in the intermediate synchronic document (see [<cite><a class="bibref" href="#bib-TTML2">TTML2</a></cite>] for more details on when
+          flowed into the region for presentation in the intermediate synchronic document (see [<cite><a class="bibref" href="#bib-TTML1">TTML1</a></cite>] for more details on when
           a <code>set</code> animation element is applied to content elements).</li>
         </ul>
 
@@ -1877,7 +1960,7 @@
           G<sub>n</sub> using the corresponding style information.</li>
         </ul>
 
-        <p>Two glyphs are identical if and only if the following [<cite><a class="bibref" href="#bib-TTML2">TTML2</a></cite>] styles are identical:</p>
+        <p>Two glyphs are identical if and only if the following [<cite><a class="bibref" href="#bib-TTML1">TTML1</a></cite>] styles are identical:</p>
 
         <ul>
           <li><code>tts:color</code></li>
@@ -2007,127 +2090,96 @@
       </section>
     </section><!-- start CFF-TT 1.0.7 -->
 
-    <section id="layout-model">
-      <h3 aria-level="2" role="heading" id="h3_layout-model"><span class="secno">7.2 </span>Layout Model</h3>
-
-      <section id="general-3">
-        <h4 aria-level="3" role="heading" id="h4_general-3"><span class="secno">7.2.1 </span>General</h4>
-
-        <p>The height and width of the area occupied by text within a region depend on line height as well as the width of, and
-        spacing between (kerning), individual glyphs. The following allows the area occupied by text to be precisely determined,
-        and thus region extent to be set such that text flows without clipping.</p>
-      </section>
-
-      <section id="reference-fonts">
-        <h4 aria-level="3" role="heading" id="h4_reference-fonts"><span class="secno">7.2.2 </span>Reference Fonts</h4>
-
-        <p>A glyph that matches one of the combinations of computed font family and code point listed in the table below <em class="rfc2119" title="SHALL">SHALL</em> be laid out using
-		metrics equal to the metrics of the specified reference font, unless the glyph is not defined by the
-        reference font.</p>
-
-        <table class="simple">
-          <thead>
-            <tr>
-              <th>Computed Font Family</th>
-
-              <th>Code Points</th>
-
-              <th>Reference Font</th>
-            </tr>
-          </thead>
-
-          <tbody>
-            <tr>
-              <td>monospaceSerif</td>
-
-              <td>
-                All code points specified in <a href="#recommended-unicode-code-points-per-language"></a>
-              </td>
-
-              <td>
-                <a href="http://www.microsoft.com/typography/fonts/family.aspx?FID=10">http://www.microsoft.com/typography/fonts/family.aspx?FID=10</a>
-                (Courier New)
-              </td>
-            </tr>
-
-            <tr>
-              <td>proportionalSansSerif</td>
-
-              <td>
-                All code points specified in <a href="#recommended-unicode-code-points-per-language"></a>, excluding the code
-                points defined for Semitic languages alone.
-              </td>
-
-              <td>
-                <a href="http://www.microsoft.com/typography/fonts/family.aspx?FID=8">http://www.microsoft.com/typography/fonts/family.aspx?FID=8</a>
-                (Arial) or <a href="http://www.linotype.com/en/526/Helvetica-family.html">http://www.linotype.com/en/526/Helvetica-family.html</a>
-                (Helvetica)
-              </td>
-            </tr>
-          </tbody>
-        </table>
-
-        <div class="note"><div class="note-title" aria-level="4" role="heading" id="h_note_11"><span>Note</span></div><p class="">Implementations can use use fonts other than those specified above. Two fonts with equal metrics can have a
-        different appearance, but flow identically.</p></div>
-
-        <div class="note"><div class="note-title" aria-level="4" role="heading" id="h_note_12"><span>Note</span></div><p class="">proportionalSansSerif is not used in practice for Hebrew and Arabic captions and subtitles.</p></div>
-      </section>
-
-      <section id="line-height-and-centering">
-        <h4 aria-level="3" role="heading" id="h4_line-height-and-centering"><span class="secno">7.2.3 </span>Line Height and Centering</h4>
-
-        <p>The computed value of <code>tts:lineHeight</code> shall be equal to 120% if tts:lineHeight="normal".</p>
-
-        <p><code>tts:lineHeight</code> values expressed using the percentage metric shall be relative to the largest font size on
-        the line.</p>
-
-        <aside class="example"><div class="example-title"><span>Example 6</span></div>
-          Assuming that the root container is ultimately rendered at a 1920×1080 resolution and
-          <code>tts:lineHeight</code>="100%", a line mixing glyphs with font size of "10px", "36px"
-          and "1c" has a computed value of <code>tts:lineHeight</code> equal to "72px".
-        </aside>
-
-        <p>If the computed value of <code>tts:lineHeight</code> is not supported, then a presentation processor <em class="rfc2119" title="SHALL">SHALL</em> use the next
-        highest supported value.</p>
-
-        <aside class="example"><div class="example-title"><span>Example 7</span></div>
-          Three lines of 12px characters with <code>tts:lineHeight</code>="normal" has a height of 45px = ⌈12px *
-          120%⌉ × 3 assuming line heights have 1px resolution.
-        </aside>
-
-        <p>White space in excess of the largest font size on the line <em class="rfc2119" title="SHALL">SHALL</em> be allocated evenly top and bottom (half-leading). Note
-        that inter-baseline separation includes any leading.</p><!-- end CFF-TT 1.0.7 -->
-
-        <div class="note"><div class="note-title" aria-level="4" role="heading" id="h_note_13"><span>Note</span></div><p class="">Since font size can change on a line and text can wrap, it is necessary to first determine the glyphs
-        present on a line before determining line height.</p></div>
-
-        <div class="note"><div class="note-title" aria-level="4" role="heading" id="h_note_14"><span>Note</span></div><p class="">Glyphs that do not extend beyond the specific <code>tts:fontSize</code> value will not clip top or
-        bottom.</p></div>
-      </section>
+    <section id="reference-fonts">
+      <h3 aria-level="2" role="heading" id="h3_reference-fonts"><span class="secno">7.2 </span>Reference Fonts</h3>
+
+      <p>The height and width of the area occupied by text within a region depend on line height as well as the width of, and
+      spacing between (kerning), individual glyphs. The following allows the area occupied by text to be closely determined, and
+      thus the region extent to be set such that text flows without clipping.</p>
+
+      <p>A glyph that matches one of the combinations of computed font family and code point listed in the table below <em class="rfc2119" title="SHALL">SHALL</em> be
+      laid out using metrics equal to the metrics of the specified reference font, unless the glyph is not defined by the reference
+      font.</p>
+
+      <table class="simple">
+        <thead>
+          <tr>
+            <th>Computed Font Family</th>
+
+            <th>Code Points</th>
+
+            <th>Reference Font</th>
+          </tr>
+        </thead>
+
+        <tbody>
+          <tr>
+            <td>monospaceSerif</td>
+
+            <td>
+              All code points specified in <a href="#recommended-unicode-code-points-per-language"></a>
+            </td>
+
+            <td>
+              <a href="http://www.microsoft.com/typography/fonts/family.aspx?FID=10">http://www.microsoft.com/typography/fonts/family.aspx?FID=10</a>
+              (Courier New)
+            </td>
+          </tr>
+
+          <tr>
+            <td>proportionalSansSerif</td>
+
+            <td>
+              All code points specified in <a href="#recommended-unicode-code-points-per-language"></a>, excluding the code points
+              defined for Semitic languages alone.
+            </td>
+
+            <td>
+              <a href="http://www.microsoft.com/typography/fonts/family.aspx?FID=8">http://www.microsoft.com/typography/fonts/family.aspx?FID=8</a>
+              (Arial) or <a href="http://www.linotype.com/en/526/Helvetica-family.html">http://www.linotype.com/en/526/Helvetica-family.html</a>
+              (Helvetica)
+            </td>
+          </tr>
+        </tbody>
+      </table>
+
+      <div class="note"><div class="note-title" aria-level="3" role="heading" id="h_note_11"><span>Note</span></div><p class="">Implementations can use use fonts other than those specified above. Two fonts with equal metrics can have a
+      different appearance, but flow identically.</p></div>
+
+      <div class="note"><div class="note-title" aria-level="3" role="heading" id="h_note_12"><span>Note</span></div><p class="">proportionalSansSerif is not used in practice for Hebrew and Arabic captions and subtitles.</p></div>
     </section>
   </section>
 
   <section class="appendix" id="recommended-character-sets-1">
     <!--OddPage--><h2 aria-level="1" role="heading" id="h2_recommended-character-sets-1"><span class="secno">A. </span>Recommended Character Sets</h2>
-	
-	
-	<p>When authoring textual content, authors are encouraged to select from sets of characters based on the language expressed using the xml:lang. The idea is to increase the confidence that the text will be presented correctly by implementations targeting specific locales.</p>
-
-	<p>Specifically, for a given language, an author should choose characters from the set resulting from the union of the following sets:
-          </p><li>the main and punctuation exemplar character sets specified for the language in [<cite><a class="bibref" href="#bib-CLDR">CLDR</a></cite>]; and</li>
-          <li>the digits and symbols included in all numberSystems specified for the language in [<cite><a class="bibref" href="#bib-CLDR">CLDR</a></cite>]; and</li>
-          <li>the common character set specified in Table 1; and</li>
-          <li>supplementary characters specified for the language in Table 2, if any</li>
-        
-	<p></p>
-	
-<p>Some of these sets may overlap.</p>
-
-<p>Table 1 captures the set of characters intended to be available to authors across all languages.
-The terms used in the table are defined in [<cite><a class="bibref" href="#bib-UNICODE">UNICODE</a></cite>].</p>
+
+    <p>When authoring textual content, authors are encouraged to select from sets of characters based on the language expressed
+    using the xml:lang. The idea is to increase the confidence that the text will be presented correctly by implementations
+    targeting specific locales.</p>
+
+    <p>Specifically, for a given language, an author should choose characters from the set resulting from the union of the
+    following sets:</p>
+
+    <ul>
+      <li>the main and punctuation exemplar character sets specified for the language in [<cite><a class="bibref" href="#bib-CLDR">CLDR</a></cite>]; and</li>
+
+      <li>the digits and symbols included in all numberSystems specified for the language in [<cite><a class="bibref" href="#bib-CLDR">CLDR</a></cite>]; and</li>
+
+      <li>the common character set specified in Table 1; and</li>
+
+      <li>supplementary characters specified for the language in Table 2, if any</li>
+    </ul>
+
+    <p>Some of these sets may overlap.</p>
+
+    <p>Table 1 captures the set of characters intended to be available to authors across all languages. The terms used in the table
+    are defined in [<cite><a class="bibref" href="#bib-UNICODE">UNICODE</a></cite>].</p>
 
     <table class="simple">
-	<caption>Table 1. Common Character Set.</caption>
+      <caption>
+        Table 1. Common Character Set.
+      </caption>
+
       <tbody><tr>
         <th>(Basic Latin)</th>
       </tr>
@@ -2159,8 +2211,8 @@
       <tr>
         <td>U+00A0 - U+00FF</td>
       </tr>
-	  
-	  <tr>
+
+      <tr>
         <th>(Number Forms)</th>
       </tr>
 
@@ -2199,8 +2251,8 @@
       <tr>
         <td>U+017E : LATIN SMALL LETTER Z WITH CARON</td>
       </tr>
-	  
-	  <tr>
+
+      <tr>
         <th>(Box Drawing)</th>
       </tr>
 
@@ -2235,8 +2287,8 @@
       <tr>
         <td>U+0192 : LATIN SMALL LETTER F WITH HOOK</td>
       </tr>
-	  
-	 <tr>
+
+      <tr>
         <th>(Block Elements)</th>
       </tr>
 
@@ -2251,7 +2303,8 @@
       <tr>
         <td>U+02DC : SMALL TILDE</td>
       </tr>
-	        <tr>
+
+      <tr>
         <th>(Geometric Shapes)</th>
       </tr>
 
@@ -2274,8 +2327,8 @@
       <tr>
         <td>U+2030 - U+203A : General punctuation</td>
       </tr>
-	  
-	        <tr>
+
+      <tr>
         <th>(Musical Symbols)</th>
       </tr>
 
@@ -2298,17 +2351,18 @@
       <tr>
         <td>U+20AC : EURO SIGN</td>
       </tr>
-    </tbody></table>
-
-	<br>
-	<p>
-	Table 2 specifies supplementary character set that have proven useful in captioning and subtitling applications for a number of selected languages. Table 2 is non-exhaustive, and will be extended as needs arise.</p>
-	
+    </tbody></table><br>
+
+    <p>Table 2 specifies supplementary character set that have proven useful in captioning and subtitling applications for a number
+    of selected languages. Table 2 is non-exhaustive, and will be extended as needs arise.</p>
+
     <table class="simple">
-	<caption>Table 2. Supplementary Character Sets.</caption>
+      <caption>
+        Table 2. Supplementary Character Sets.
+      </caption>
+
       <thead>
         <tr>
-
           <th>Primary language subtag</th>
 
           <th>Characters</th>
@@ -2316,56 +2370,42 @@
       </thead>
 
       <tbody>
-
-
-		<tr>
-
+        <tr>
           <td>lv, lt, et, tr, hr, cs, pl, sl, sk</td>
 
-          <td>
-          (Latin Extended-A)<br>
+          <td>(Latin Extended-A)<br>
           U+0100 – U+017F</td>
         </tr>
-		
-		<tr>
-
+
+        <tr>
           <td>nl</td>
 
-          <td>
-           (Combining Diacritical Marks)<br>
+          <td>(Combining Diacritical Marks)<br>
           U+0301</td>
-
         </tr>
-		
-				<tr>
-
+
+        <tr>
           <td>ro</td>
 
-          <td>
-          (Latin Extended-A)<br>
+          <td>(Latin Extended-A)<br>
           U+0100 – U+017F<br>
-		  (Latin Extended-B)<br>
-		  U+0218 – U+0219<br>
-U+021A – U+021B
-        </td></tr>
-		
-	
-
-          <tr><td>el</td>
-
-          <td>
-		  (Combining Diacritical Marks)<br>
-		  U+0301<br>
-		U+0308<br>
+          (Latin Extended-B)<br>
+          U+0218 – U+0219<br>
+          U+021A – U+021B</td>
+        </tr>
+
+        <tr>
+          <td>el</td>
+
+          <td>(Combining Diacritical Marks)<br>
+          U+0301<br>
+          U+0308<br>
           (Greek and Coptic)<br>
           U+0386 – U+0387<br>
-          U+0388 – U+03CE 
-		  </td>
+          U+0388 – U+03CE</td>
         </tr>
 
-
         <tr>
-
           <td>pt, es</td>
 
           <td>(Currency symbols)<br>
@@ -2373,126 +2413,139 @@
           U+20B3</td>
         </tr>
 
-
-
         <tr>
           <td>ar</td>
 
-          <td>
-		  (Arabic)<br>
+          <td>(Arabic)<br>
           U+060C – U+060D<br>
           U+061B<br>
           U+061E – U+061F<br>
           U+0621 – U+063A<br>
           U+0640 – U+0652<br>
           U+0660 – U+066D<br>
-		  U+0670<br>
-		  </td>
+          U+0670<br></td>
         </tr>
 
         <tr>
           <td>he</td>
 
-          <td>
-          (Hebrew)<br>
+          <td>(Hebrew)<br>
           U+05B0 – U+05C3<br>
           U+05D0 – U+05EA<br>
           U+05F3 – U+05F4</td>
         </tr>
 
-
-
-
         <tr>
-
           <td>bs, bg, mk, ru, sr</td>
 
-          <td>
-          (Latin Extended-A)<br>
+          <td>(Latin Extended-A)<br>
           U+0100 – U+017F<br>
           (Cyrillic)<br>
           U+0400 – U+045F</td>
         </tr>
 
         <tr>
-
           <td>uk</td>
 
-          <td>
-          (Latin Extended-A)<br>
-          U+0100 – U+017F<br>
-          (Cyrillic)<br>
-          U+0400 – U+045F<br>	
-		  			U+0490 – U+0491<br>
-		  (Spacing Modifier Letters)<br>
-		  U+02BC<br>
-(Letterlike Symbols)<br>
-		U+2116
-
-		  
-		  
-		  </td>
-        </tr>
-
-
-
-
-        <tr>
-
-          <td>kk</td>
-
-          <td>
-		   (Latin Extended-A)<br>
+          <td>(Latin Extended-A)<br>
           U+0100 – U+017F<br>
           (Cyrillic)<br>
           U+0400 – U+045F<br>
-		  U+0492 – U+0493<br>
-			U+049A – U+049B<br>
-			U+04A2 – U+04A3<br>
-			U+04AE – U+04B1<br>
-			U+04BA – U+04BB<br>
-			U+04D8 – U+04D9<br>
-			U+04E8 – U+04E9<br>
-
-		  
-		  
-		  
-		  </td>
+          U+0490 – U+0491<br>
+          (Spacing Modifier Letters)<br>
+          U+02BC<br>
+          (Letterlike Symbols)<br>
+          U+2116</td>
         </tr>
 
         <tr>
-
+          <td>kk</td>
+
+          <td>(Latin Extended-A)<br>
+          U+0100 – U+017F<br>
+          (Cyrillic)<br>
+          U+0400 – U+045F<br>
+          U+0492 – U+0493<br>
+          U+049A – U+049B<br>
+          U+04A2 – U+04A3<br>
+          U+04AE – U+04B1<br>
+          U+04BA – U+04BB<br>
+          U+04D8 – U+04D9<br>
+          U+04E8 – U+04E9<br></td>
+        </tr>
+
+        <tr>
           <td>hu</td>
 
-          <td>
-          (Latin Extended-A)<br>
+          <td>(Latin Extended-A)<br>
           U+0100 – U+017F<br>
-		  (General Punctuation)<br>
-		  U+2052<br>
-		  (Miscellaneous Mathematical Symbols-A)<br>
-U+27E8–U+27E9
-</td>
+          (General Punctuation)<br>
+          U+2052<br>
+          (Miscellaneous Mathematical Symbols-A)<br>
+          U+27E8–U+27E9</td>
         </tr>
       </tbody>
     </table>
   </section>
 
-  <section class="appendix" id="schema">
-    <!--OddPage--><h2 aria-level="1" role="heading" id="h2_schema"><span class="secno">B. </span>Schema</h2>
-
-    <p><em>TBD</em></p>
+  <section class="appendix" id="extensions-1">
+    <!--OddPage--><h2 aria-level="1" role="heading" id="h2_extensions-1"><span class="secno">B. </span>Extensions</h2>
+
+    <section class="appendix" id="general-2">
+      <h3 aria-level="2" role="heading" id="h3_general-2"><span class="secno">B.1 </span>General</h3>
+
+      <p>The following sections define extension designations, expressed as relative URIs (fragment identifiers) with respect to
+      the TT Extension Namespace base URI (see [<cite><a class="bibref" href="#bib-TTML1">TTML1</a></cite>].</p>
+    </section>
+
+    <section class="appendix" id="progressivelydecodable">
+      <h3 aria-level="2" role="heading" id="h3_progressivelydecodable"><span class="secno">B.2 </span>#progressivelyDecodable</h3>
+
+      <p>A TTML transformation processor supports the <code>#progressivelyDecodable</code> feature if it recognizes and is capable
+      of transforming values of the <a href="#h3_ttp-progressivelydecodable"><code>ttp:progressivelyDecodable</code></a>.</p>
+
+      <p>A TTML presentation processor supports the <code>#progressivelyDecodable</code> feature if it implements presentation
+      semantic support for values of the <a href="#h3_ttp-progressivelydecodable"><code>ttp:progressivelyDecodable</code></a>
+      attribute.</p>
+    </section>
+
+    <section class="appendix" id="aspectratio">
+      <h3 aria-level="2" role="heading" id="h3_aspectratio"><span class="secno">B.3 </span>#aspectRatio</h3>
+
+      <p>A TTML transformation processor supports the <code>#aspectRatio</code> feature if it recognizes and is capable of
+      transforming values of the <a href="#h3_ttp-aspectratio"><code>ttp:aspectRatio</code></a>.</p>
+
+      <p>A TTML presentation processor supports the <code>#aspectRatio</code> feature if it implements presentation semantic
+      support for values of the <a href="#h3_ttp-aspectratio"><code>ttp:aspectRatio</code></a> attribute.</p>
+    </section>
+
+    <section class="appendix" id="forceddisplay">
+      <h3 aria-level="2" role="heading" id="h3_forceddisplay"><span class="secno">B.4 </span>#forcedDisplay</h3>
+
+      <p>A TTML transformation processor supports the <code>#forcedDisplay</code> feature if it recognizes and is capable of
+      transforming values of the <a href="#h3_tts-forceddisplay"><code>tts:forcedDisplay</code></a>.</p>
+
+      <p>A TTML presentation processor supports the <code>#forcedDisplay</code> feature if it implements presentation semantic
+      support for values of the <a href="#h3_tts-forceddisplay"><code>tts:forcedDisplay</code></a> attribute.</p>
+    </section>
+
+    <section class="appendix" id="http-www.smpte-ra.org-schemas-2052-1-2010-smpte-tt-image">
+      <h3 aria-level="2" role="heading" id="h3_http-www.smpte-ra.org-schemas-2052-1-2010-smpte-tt-image"><span class="secno">B.5 </span>http://www.smpte-ra.org/schemas/2052-1/2010/smpte-tt#image</h3>
+
+      <p>The <code>http://www.smpte-ra.org/schemas/2052-1/2010/smpte-tt#image</code> extension is specified in [<cite><a class="bibref" href="#bib-ST2052-1">ST2052-1</a></cite>].</p>
+    </section>
   </section>
 
 
-<section id="references" class="appendix" typeof="bibo:Chapter" resource="#ref" rel="bibo:Chapter"><!--OddPage--><h2 aria-level="1" role="heading" id="h2_references"><span class="secno">C. </span>References</h2><section id="normative-references" typeof="bibo:Chapter" resource="#ref" rel="bibo:Chapter"><h3 aria-level="2" role="heading" id="h3_normative-references"><span class="secno">C.1 </span>Normative references</h3><dl class="bibliography" about=""><dt id="bib-MHP">[MHP]</dt><dd rel="dcterms:requires">ETSI TS 101 812 V1.3.1, Digital Video Broadcasting (DVB); Multimedia Home
+<section id="references" class="appendix" typeof="bibo:Chapter" resource="#references" rel="bibo:Chapter"><!--OddPage--><h2 aria-level="1" role="heading" id="h2_references"><span class="secno">C. </span>References</h2><section id="normative-references" typeof="bibo:Chapter" resource="#normative-references" rel="bibo:Chapter"><h3 aria-level="2" role="heading" id="h3_normative-references"><span class="secno">C.1 </span>Normative references</h3><dl class="bibliography" about=""><dt id="bib-MHP">[MHP]</dt><dd rel="dcterms:requires">ETSI TS 101 812 V1.3.1, Digital Video Broadcasting (DVB); Multimedia Home
 </dd><dt id="bib-RFC2119">[RFC2119]</dt><dd rel="dcterms:requires">S. Bradner. <a href="http://www.ietf.org/rfc/rfc2119.txt"><cite>Key words for use in RFCs to Indicate Requirement Levels.</cite></a> March 1997. Internet RFC 2119.  URL: <a href="http://www.ietf.org/rfc/rfc2119.txt">http://www.ietf.org/rfc/rfc2119.txt</a> 
-</dd><dt id="bib-SDPUS">[SDPUS]</dt><dd rel="dcterms:requires">World Wide Web Consortium (W3C). <a href="http://www.w3.org/TR/ttml10-sdp-us/">TTML Simple Delivery Profile for Closed Captions (US)</a> (W3C Working Group Note, 05 February 2013)
-</dd><dt id="bib-SUBM">[SUBM]</dt><dd rel="dcterms:requires">World Wide Web Consortium (W3C). <a href="http://www.w3.org/Submission/2013/SUBM-ttml-ww-profiles-20130607/">TTML Text and Image Profiles for Internet Media Subtitles and Captions</a> (Member Submission, 07 June 2013)
-</dd><dt id="bib-TTML2">[TTML2]</dt><dd rel="dcterms:requires">World Wide Web Consortium (W3C). Timed Text Markup Language 2 (TTML 2)
+</dd><dt id="bib-ST2052-1">[ST2052-1]</dt><dd rel="dcterms:requires">SMPTE ST 2052-1, Timed Text Format (SMPTE-TT)
+</dd><dt id="bib-TTML1">[TTML1]</dt><dd rel="dcterms:requires">World Wide Web Consortium (W3C). Timed Text Markup Language 1 (TTML1) (Second Edition)
 </dd><dt id="bib-UNICODE">[UNICODE]</dt><dd rel="dcterms:requires"><a href="http://www.unicode.org/versions/latest/"><cite>The Unicode Standard</cite></a>. URL: <a href="http://www.unicode.org/versions/latest/">http://www.unicode.org/versions/latest/</a>
 </dd><dt id="bib-xml-names">[xml-names]</dt><dd rel="dcterms:requires">Tim Bray; Dave Hollander; Andrew Layman; Richard Tobin; Henry Thompson et al. <a href="http://www.w3.org/TR/xml-names"><cite>Namespaces in XML 1.0 (Third Edition)</cite></a>. 8 December 2009. W3C Recommendation. URL: <a href="http://www.w3.org/TR/xml-names">http://www.w3.org/TR/xml-names</a>
-</dd></dl></section><section id="informative-references" typeof="bibo:Chapter" resource="#ref" rel="bibo:Chapter"><h3 aria-level="2" role="heading" id="h3_informative-references"><span class="secno">C.2 </span>Informative references</h3><dl class="bibliography" about=""><dt id="bib-CEA-608">[CEA-608]</dt><dd rel="dcterms:references"><a href="http://www.ce.org/Standards/Standard-Listings/R4-3-Television-Data-Systems-Subcommittee/Line-21-Data-Service.aspx">Line-21 Data Services</a>, ANSI/CEA Standard.
+</dd></dl></section><section id="informative-references" typeof="bibo:Chapter" resource="#informative-references" rel="bibo:Chapter"><h3 aria-level="2" role="heading" id="h3_informative-references"><span class="secno">C.2 </span>Informative references</h3><dl class="bibliography" about=""><dt id="bib-CEA-608">[CEA-608]</dt><dd rel="dcterms:references"><a href="http://www.ce.org/Standards/Standard-Listings/R4-3-Television-Data-Systems-Subcommittee/Line-21-Data-Service.aspx">Line-21 Data Services</a>, ANSI/CEA Standard.
 </dd><dt id="bib-CEA-708">[CEA-708]</dt><dd rel="dcterms:references"><a href="http://www.ce.org/Standards/Standard-Listings/R4-3-Television-Data-Systems-Subcommittee/CEA-708-D.aspx">Digital Television (DTV) Closed Captioning</a>, ANSI/CEA Standard.
 </dd><dt id="bib-CLDR">[CLDR]</dt><dd rel="dcterms:references">Unicode Consortium. <a href="http://cldr.unicode.org">The Common Locale Data Repository Project</a>
-</dd><dt id="bib-ST2052-1">[ST2052-1]</dt><dd rel="dcterms:references">SMPTE ST 2052-1, Timed Text Format (SMPTE-TT)
+</dd><dt id="bib-SDPUS">[SDPUS]</dt><dd rel="dcterms:references">World Wide Web Consortium (W3C). <a href="http://www.w3.org/TR/ttml10-sdp-us/">TTML Simple Delivery Profile for Closed Captions (US)</a> (W3C Working Group Note, 05 February 2013)
+</dd><dt id="bib-SUBM">[SUBM]</dt><dd rel="dcterms:references">World Wide Web Consortium (W3C). <a href="http://www.w3.org/Submission/2013/SUBM-ttml-ww-profiles-20130607/">TTML Text and Image Profiles for Internet Media Subtitles and Captions</a> (Member Submission, 07 June 2013)
 </dd></dl></section></section></body></html>
\ No newline at end of file
--- a/ttml-ww-profiles/ttml-ww-profiles.source.html	Thu Mar 27 10:43:17 2014 -0600
+++ b/ttml-ww-profiles/ttml-ww-profiles.source.html	Tue Apr 15 16:31:53 2014 -0700
@@ -4,8 +4,8 @@
 <head>
   <meta charset='utf-8'>
 
-  <title>TTML Text and Image Profiles for Internet Media Subtitles and Captions</title>
-  <script src='http://www.w3.org/Tools/respec/respec-w3c-common' async class='remove'>
+  <title>TTML Text and Image Profiles for Internet Media Subtitles and Captions 1.0</title>
+  <script src='http://www.w3.org/Tools/respec/respec-w3c-common' async="" class='remove'>
 </script>
   <script class='remove'>
 var respecConfig = {
@@ -16,16 +16,16 @@
                   ,   wgURI: "http://www.w3.org/AudioVideo/TT/"
                   ,   wgPublicList: "public-tt"
                   ,   wgPatentURI: "http://www.w3.org/2004/01/pp-impl/34314/status"
-				  ,   edDraftURI: "ttml-ww-profiles.html"
+                                  ,   edDraftURI: "ttml-ww-profiles.html"
                   ,   localBiblio:  {
-				  "SUBM": "World Wide Web Consortium (W3C). <a href='http://www.w3.org/Submission/2013/SUBM-ttml-ww-profiles-20130607/'>TTML Text and Image Profiles for Internet Media Subtitles and Captions</a> (Member Submission, 07 June 2013)",
-                  "TTML2":  "World Wide Web Consortium (W3C). Timed Text Markup Language 2 (TTML 2)",
+                                  "SUBM": "World Wide Web Consortium (W3C). <a href='http://www.w3.org/Submission/2013/SUBM-ttml-ww-profiles-20130607/'>TTML Text and Image Profiles for Internet Media Subtitles and Captions</a> (Member Submission, 07 June 2013)",
+                  "TTML1":  "World Wide Web Consortium (W3C). Timed Text Markup Language 1 (TTML1) (Second Edition)",
                   "CEA-608": "<a href='http://www.ce.org/Standards/Standard-Listings/R4-3-Television-Data-Systems-Subcommittee/Line-21-Data-Service.aspx'>Line-21 Data Services</a>, ANSI/CEA Standard.",
                   "CEA-708": "<a href='http://www.ce.org/Standards/Standard-Listings/R4-3-Television-Data-Systems-Subcommittee/CEA-708-D.aspx'>Digital Television (DTV) Closed Captioning</a>, ANSI/CEA Standard.",
                   "MHP" : "ETSI TS 101 812 V1.3.1, Digital Video Broadcasting (DVB); Multimedia Home",
                   "ST2052-1": "SMPTE ST 2052-1, Timed Text Format (SMPTE-TT)",
-				  "SDPUS": "World Wide Web Consortium (W3C). <a href='http://www.w3.org/TR/ttml10-sdp-us/'>TTML Simple Delivery Profile for Closed Captions (US)</a> (W3C Working Group Note, 05 February 2013)",
-				  "CLDR": "Unicode Consortium. <a href='http://cldr.unicode.org'>The Common Locale Data Repository Project</a>"
+                                  "SDPUS": "World Wide Web Consortium (W3C). <a href='http://www.w3.org/TR/ttml10-sdp-us/'>TTML Simple Delivery Profile for Closed Captions (US)</a> (W3C Working Group Note, 05 February 2013)",
+                                  "CLDR": "Unicode Consortium. <a href='http://cldr.unicode.org'>The Common Locale Data Repository Project</a>"
               }
         };
   </script>
@@ -48,27 +48,25 @@
 
 <body>
   <section id='abstract'>
-    <p>This document specifies two profiles of [[!TTML2]]: a text-only profile and an image-only
-    profile. These profiles are intended to be used across subtitle and caption delivery applications worldwide, thereby
-    simplifying interoperability, consistent rendering and conversion to other subtitling and captioning formats. The text profile
-    is a superset of [[!SDPUS]].</p>
-
-    <p>Both profiles are based on [[!SUBM]].</p>
+    <p>This document specifies two profiles of [[!TTML1]]: a text-only profile and an image-only profile. These profiles are
+    intended to be used across subtitle and caption delivery applications worldwide, thereby simplifying interoperability,
+    consistent rendering and conversion to other subtitling and captioning formats. The text profile is a superset of
+    [[SDPUS]].</p>
+
+    <p>Both profiles are based on [[SUBM]].</p>
   </section>
-  
-      <section id='sotd'>
-       <p>
-          </p>
-    </section>
+
+  <section id='sotd'></section>
 
   <section id='scope'>
     <h2>Scope</h2>
 
-    <p>This document specifies two profiles of [[!TTML2]]: a text-only profile and an image-only profile. These profiles are
+    <p>This document specifies two profiles of [[!TTML1]]: a text-only profile and an image-only profile. These profiles are
     intended for subtitle and caption delivery worldwide, including dialog language translation, content description, captions for
     deaf and hard of hearing, etc.</p>
-	
-	 <p>The profiles are strict subset of [[!TTML2]] and the text-only profile a strict supersets of [[!SDPUS]].</p>
+
+    <p>The text-only profile is a strict superset of [[SDPUS]] and the image-only profile uses extensions specified in
+    [[!ST2052-1]].</p>
   </section>
 
   <section id="conformance">
@@ -132,6 +130,30 @@
 
             <td>http://www.w3.org/ns/ttml/profile/imsc</td>
           </tr>
+
+          <tr>
+            <td>ttp</td>
+
+            <td>http://www.w3.org/ns/ttml#parameter</td>
+          </tr>
+
+          <tr>
+            <td>tts</td>
+
+            <td>http://www.w3.org/ns/ttml#styling</td>
+          </tr>
+
+          <tr>
+            <td><em>none</em></td>
+
+            <td>http://www.w3.org/ns/ttml/feature/</td>
+          </tr>
+
+          <tr>
+            <td><em>none</em></td>
+
+            <td>http://www.w3.org/ns/ttml/extension/</td>
+          </tr>
         </tbody>
       </table>
 
@@ -142,18 +164,36 @@
     <section>
       <h3>Related Video Object</h3>
 
-      <section>
-        <h4>General</h4>
-
-        <p>A subtitle document MAY be associated with a related video object, which SHALL consist of a sequence of frames, each a
-        rectangular array of pixels.</p>
-      </section>
+      <p>A subtitle document MAY be associated with a related video object, which SHALL consist of a sequence of frames, each a
+      rectangular array of pixels.</p>
+    </section>
+
+    <section>
+      <h3>Synchronization</h3>
+
+      <p>Each intermediate synchronic document of the subtitle document is intended to be displayed on a specific frame and removed
+      on a specific frame of the related video object.</p>
+
+      <p>A media time expression M SHALL correspond to the frame of the related video object with the presentation time that is the
+      closest to, but not less, than M.</p>
+
+      <p>If <code>ttp:frameRate</code> is specified, then the product of <code>ttp:frameRate</code> and
+      <code>ttp:frameRateMultiplier</code> SHALL be the frame rate of the related video object.</p>
+
+      <aside class="example">
+        A media time expression of 00:00:05.1 corresponds to frame ceiling(5.1 × ( 1000 / 1001 × 30) = 153 of a related video
+        object with a frame rate of 1000 / 1001 × 30 ≈ 29.97.
+      </aside>
+    </section>
+
+    <section>
+      <h3>Extensions</h3>
 
       <section>
-        <h4>Root Container</h4>
-
-        <p class='issue'>See <a href="http://www.w3.org/AudioVideo/TT/tracker/issues/201">ISSUE-201</a> for a discussion of aspect
-        ratio in the context of [[!TTML2]].</p>
+        <h4>ttp:aspectRatio</h4>
+
+        <p>The <code>ttp:aspectRatio</code> attributes allows authorial control of the mapping of the root container of a subtitle
+        document to the related video object frame.</p>
 
         <p>The root container of a subtitle document SHALL be mapped to the related video object frame according to the
         following:</p>
@@ -168,7 +208,8 @@
 
               <li>the center of the rectangular area is colocated with the center of the related video object frame,</li>
 
-              <li>the rectangular area (including its boundary) is entirely within the related video object frame (including its boundary), and</li>
+              <li>the rectangular area (including its boundary) is entirely within the related video object frame (including its
+              boundary), and</li>
 
               <li>the rectangular area has a height or width equal to that of the related video object frame.</li>
             </ol>
@@ -191,67 +232,107 @@
       </section>
 
       <section>
-        <h4>Synchronization</h4>
-
-        <p>Each intermediate synchronic document of the subtitle document is intended to be displayed on a specific frame and
-        removed on a specific frame of the related video object.</p>
-
-        <p>A media time expression M SHALL correspond to the frame of the related video object with the presentation time that is
-        the closest to, but not less, than M.</p>
-
-        <p>If <code>ttp:frameRate</code> is specified, then the product of <code>ttp:frameRate</code> and
-        <code>ttp:frameRateMultiplier</code> SHALL be the frame rate of the related video object.</p>
-
-        <aside class="example">
-          A media time expression of 00:00:05.1 corresponds to frame ceiling(5.1 × ( 1000 / 1001 × 30) = 153 of a related video
-          object with a frame rate of 1000 / 1001 × 30 ≈ 29.97.
-        </aside>
-      </section>
-    </section>
-
-    <section>
-      <h3>Progressively Decodable</h3>
-
-      <p>A progressively decodable subtitle document is a subtitle document structured to facilitate processing before the document
-      is received in its entirety. It shall conform to the following:</p>
-
-      <ol>
-        <li>elements appear in the document in increasing order according to their resolved begin time;</li>
-
-        <li>no element references another element (i) occurring later in the document or (ii) with a later begin time; and</li>
-
-        <li>a <code>imsc:progressivelyDecodable</code> attribute with value &quot;true&quot; is present on the <code>tt</code>
-        element.</li>
-      </ol>
-
-      <p>The <code>imsc:progressivelyDecodable</code> attribute shall conform to the following syntax:</p>
-
-      <table class="syntax">
-        <tbody>
-          <tr>
-            <td>
-              <div class="exampleInner">
-                <pre>
+        <h4>ttp:progressivelyDecodable</h4>
+
+        <p>A progressively decodable subtitle document is a subtitle document structured to facilitate processing before the
+        document is received in its entirety. It shall conform to the following:</p>
+
+        <ol>
+          <li>elements appear in the document in increasing order according to their resolved begin time;</li>
+
+          <li>no element references another element (i) occurring later in the document or (ii) with a later begin time; and</li>
+
+          <li>a <code>ttp:progressivelyDecodable</code> attribute with value &quot;true&quot; is present on the <code>tt</code>
+          element.</li>
+        </ol>
+
+        <p>The <code>ttp:progressivelyDecodable</code> attribute shall conform to the following syntax:</p>
+
+        <table class="syntax">
+          <tbody>
+            <tr>
+              <td>
+                <div class="exampleInner">
+                  <pre>
 imsc:progressivelyDecodable
   : &quot;true&quot;
   | &quot;false&quot;
 </pre>
-              </div>
-            </td>
-          </tr>
-        </tbody>
-      </table>
-
-      <p>The initial value of <code>imsc:progressivelyDecodable</code> shall be &quot;false&quot;.</p>
-
-      <p>A <code>imsc:progressivelyDecodable</code> attribute with value &quot;false&quot; may be present on the <code>tt</code>
-      element if the subtitle document is not a progressively decodable subtitle document.</p>
-
-      <p>A <code>imsc:progressivelyDecodable</code> attribute is considered to be significant only when specified on the
-      <code>tt</code> element.</p>
-
-      <p class='note'>The placement and use of <code>div</code>, <code>region</code> and <code>span</code> that contain time
-      attributes, and (ii) the use of <code>set</code>.</p>
+                </div>
+              </td>
+            </tr>
+          </tbody>
+        </table>
+
+        <p>The initial value of <code>ttp:progressivelyDecodable</code> shall be &quot;false&quot;.</p>
+
+        <p>A <code>ttp:progressivelyDecodable</code> attribute with value &quot;false&quot; may be present on the <code>tt</code>
+        element if the subtitle document is not a progressively decodable subtitle document.</p>
+
+        <p>A <code>ttp:progressivelyDecodable</code> attribute is considered to be significant only when specified on the
+        <code>tt</code> element.</p>
+
+        <p class='note'>The placement and use of <code>div</code>, <code>region</code> and <code>span</code> that contain time
+        attributes, and (ii) the use of <code>set</code>.</p>
+      </section>
+
+      <section>
+        <h4>tts:forcedDisplay</h4>
+
+        <p>The tts:forcedDisplay signals that a block of subtitle content is identified as <em>Forced</em> subtitle content.
+        <em>Forced</em> subtitle content is subtitle content that represents audio (e.g. foreign language) or text (e.g. a sign)
+        that is not translated in the audio/video presentation.</p>
+
+        <table class="simple">
+          <colgroup>
+            <col width="25%" span="1">
+            <col span="1">
+          </colgroup>
+
+          <tbody>
+            <tr>
+              <td><em>Values:</em></td>
+
+              <td><code>false | true</code></td>
+            </tr>
+
+            <tr>
+              <td><em>Initial:</em></td>
+
+              <td><code>false</code></td>
+            </tr>
+
+            <tr>
+              <td><em>Applies to:</em></td>
+
+              <td><code>body</code>, <code>div</code>, <code>p</code>, <code>region</code>, <code>span</code></td>
+            </tr>
+
+            <tr>
+              <td><em>Inherited:</em></td>
+
+              <td>yes</td>
+            </tr>
+
+            <tr>
+              <td><em>Percentages:</em></td>
+
+              <td>N/A</td>
+            </tr>
+
+            <tr>
+              <td><em>Animatable:</em></td>
+
+              <td>discrete</td>
+            </tr>
+          </tbody>
+        </table>
+
+        <p class='note'>Although <code>tts:forcedDisplay</code>, like all the TTML style attributes, has no defined semantics on a
+        <code>br</code> content element, forcedDisplayMode will apply to a <code>br</code> content element if it is either defined
+        on an ancestor content element of the <code>br</code> content element or it is applied to a region element corresponding to
+        a region that the <code>br</code> content element is being flowed into.</p>
+      </section>
     </section>
 
     <section>
@@ -260,8 +341,8 @@
       <section>
         <h4>Presented Region</h4>
 
-        <p>A region, as defined in [[!TTML2]], is presented in a given intermediate synchronic document if all of
-        the following conditions are true:</p>
+        <p>A region, as defined in [[!TTML1]], is presented in a given intermediate synchronic document if all of the following
+        conditions are true:</p>
 
         <ol>
           <li>
@@ -278,7 +359,7 @@
           </li>
         </ol>
 
-        <p class='note'>As specified in [[!TTML2]], the initial value of <code>tts:opacity</code> is &quot;1.0&quot;, the initial
+        <p class='note'>As specified in [[!TTML1]], the initial value of <code>tts:opacity</code> is &quot;1.0&quot;, the initial
         value of <code>tts:showBackground</code> is &quot;always&quot;, and the initial value of <code>tts:display</code> is
         &quot;auto&quot;</p>
       </section>
@@ -286,9 +367,12 @@
       <section>
         <h4>Dimensions and Position</h4>
 
-        <p>All regions SHALL NOT extend beyond the root container, i.e. the intersection of the sets of coordinates belonging to a region (including its boundary) and the sets of coordinates belonging to the root container (including its boundary) is the set of coordinates belonging to the region (including its boundary).</p>
-
-        <p>No two presented regions in a given intermediate synchronic document SHALL overlap, i.e. the intersection of the sets of coordinates within each region (including its boundary) is empty.</p>
+        <p>All regions SHALL NOT extend beyond the root container, i.e. the intersection of the sets of coordinates belonging to a
+        region (including its boundary) and the sets of coordinates belonging to the root container (including its boundary) is the
+        set of coordinates belonging to the region (including its boundary).</p>
+
+        <p>No two presented regions in a given intermediate synchronic document SHALL overlap, i.e. the intersection of the sets of
+        coordinates within each region (including its boundary) is empty.</p>
       </section>
 
       <section>
@@ -307,19 +391,17 @@
 
     <section>
       <h3>Features</h3>
-	  
-	  <p>Unless specified otherwise, the features included in a subtitle document SHALL conform to the Table below:</p>
+
+      <p>Unless specified otherwise,a subtitle document SHALL conform to the following:</p>
 
       <table class='simple'>
-        <thead>
+        <tbody>
           <tr>
             <th>Feature</th>
 
             <th>Provisions</th>
           </tr>
-        </thead>
-
-        <tbody>
+
           <tr>
             <td><code>#animation</code></td>
 
@@ -710,23 +792,32 @@
           </tr>
 
           <tr>
-            <td><code>#aspectRatio</code></td>
+            <th>Extension</th>
+
+            <th>Provisions</th>
+          </tr>
+
+          <tr>
+            <td><code>http://www.w3.org/ns/ttml/extension/#aspectRatio</code></td>
 
             <td>MAY be used.</td>
           </tr>
 
           <tr>
-            <td><code>#forcedDisplay</code></td>
+            <td><code>http://www.w3.org/ns/ttml/extension/#forcedDisplay</code></td>
+
+            <td>MAY be used.</td>
+          </tr>
+
+          <tr>
+            <td><code>http://www.w3.org/ns/ttml/extension/#progressivelyDecodable</code></td>
 
             <td>MAY be used.</td>
           </tr>
         </tbody>
       </table>
 
-      <p class='issue'>See <a href="http://www.w3.org/AudioVideo/TT/tracker/issues/230">ISSUE-230</a> for a description of
-      <code>#forcedDisplay</code></p>
-
-      <p class='note'>As specified in [[!TTML2]], a <code>#time-offset-with-frames</code> expression is translated to a media time
+      <p class='note'>As specified in [[!TTML1]], a <code>#time-offset-with-frames</code> expression is translated to a media time
       M according to M = 3600 · hours + 60 · minutes + seconds + (frames ÷ (<code>ttp:frameRateMultiplier</code> ·
       <code>ttp:frameRate</code>)).</p>
     </section>
@@ -736,44 +827,47 @@
     <h2>Text Profile Constraints</h2>
 
     <section>
-      <h3>Profile Designator and Definition Document</h3>
-	  
-	    <p class='issue'>This Section is a placeholder and will be revisited based the outcome of the [[!TTML2]] profile discussions.</p>
-
-      <p>A subtitle document conforming to the Text Profile SHALL be associated with the following profile designator and profile
-      definition document:</p>
-      <pre>
-&lt;?xml version=&quot;1.0&quot; encoding=&quot;utf-8&quot;?&gt;
-&lt;profile designator=&quot;http://www.w3.org/ns/ttml/profile/imsc/text/designator&quot; xmlns=&quot;http://www.w3.org/ns/ttml#parameter&quot;&gt;
-  &lt;extensions&gt;
-    &lt;extension&gt;http://www.w3.org/ns/ttml/profile/imsc/text/feature#all&lt;/extension&gt;
-  &lt;/extensions&gt;
-&lt;/profile&gt;
-</pre>
-    </section>
-<section>
-      <h3>Recommended Character Sets</h3>
-	
-	</p>Authors should to select from the sets of characters specified in <a href="#recommended-character-sets-1"></a></p>
-	  </section>
-    <section>
-      <h3>Features</h3>
-		
-      <p class='issue'>The following assumes, but does not require, the porting of the [[ST2052-1]] <code>#backgroundImage</code>
-      features to [[!TTML2]]. See <a href="http://www.w3.org/AudioVideo/TT/tracker/issues/238">ISSUE-238</a>.</p>
-	  
-	  <p>The features included in a subtitle document SHALL conform to the Table below:</p>
+      <h3>Profile Designator</h3>
+
+      <p>A subtitle document conforming to the Text Profile SHALL be associated with the following profile designator:</p>
 
       <table class='simple'>
         <thead>
           <tr>
+            <th>Profile Name</th>
+
+            <th>Profile Designator</th>
+          </tr>
+        </thead>
+
+        <tbody>
+          <tr>
+            <td>IMSC Text</td>
+
+            <td><code>http://www.w3.org/ns/ttml/profile/imsc/text</code></td>
+          </tr>
+        </tbody>
+      </table>
+    </section>
+
+    <section>
+      <h3>Recommended Character Sets</h3>Authors should to select from the sets of characters specified in <a href=
+      "#recommended-character-sets-1"></a>
+    </section>
+
+    <section>
+      <h3>Features</h3>
+
+      <p>The subtitle document SHALL conform to the following:</p>
+
+      <table class='simple'>
+        <tbody>
+          <tr>
             <th>Feature</th>
 
             <th>Provisions</th>
           </tr>
-        </thead>
-
-        <tbody>
+
           <tr>
             <td><code>#backgroundColor-block</code></td>
 
@@ -799,24 +893,6 @@
           </tr>
 
           <tr>
-            <td><code>#backgroundImage</code></td>
-
-            <td>SHALL NOT be used.</td>
-          </tr>
-
-          <tr>
-            <td><code>#backgroundImageHorizontal</code></td>
-
-            <td>SHALL NOT be used.</td>
-          </tr>
-
-          <tr>
-            <td><code>#backgroundImageVertical</code></td>
-
-            <td>SHALL NOT be used.</td>
-          </tr>
-
-          <tr>
             <td><code>#bidi</code></td>
 
             <td>MAY be used.</td>
@@ -825,7 +901,8 @@
           <tr>
             <td><code>#color</code></td>
 
-            <td>MAY be used. The initial value of <code>tts:color</code> SHALL be &quot;white&quot;.</td>
+            <td>MAY be used. The initial value of <code>tts:color</code> SHALL be &quot;white&quot;. NOTE: This is consistent with
+            [[ST2052-1]].</td>
           </tr>
 
           <tr>
@@ -837,17 +914,15 @@
           <tr>
             <td><code>#displayAlign</code></td>
 
-            <td>MAY be used. The initial value of <code>tts:displayAlign</code> SHALL be &quot;after&quot; for the default region, as defined in [[!TTML2]].</td>
+            <td>MAY be used. The initial value of <code>tts:displayAlign</code> SHALL be &quot;after&quot; for the default region.
+            NOTE: This is consistent with [[ST2052-1]].</td>
           </tr>
 
           <tr>
             <td><code>#extent-region</code></td>
 
-            <td>
-              The <code>tts:extent</code> attribute when applied to a region element SHALL use <code>px</code> units or
-              &quot;percentage&quot; representation, and SHALL NOT use <code>em</code> units.<br>
-              Section <a href="#layout-model"></a> SHOULD be used to calculate a region extent that avoids clipping.
-            </td>
+            <td>The <code>tts:extent</code> attribute when applied to a region element SHALL use <code>px</code> units or
+            &quot;percentage&quot; representation, and SHALL NOT use <code>em</code> units.<br></td>
           </tr>
 
           <tr>
@@ -939,7 +1014,9 @@
           <tr>
             <td><code>#lineHeight</code></td>
 
-            <td>MAY be used.</td>
+            <td>MAY be used.<br>
+            An explicit <code>&lt;length&gt;</code> SHOULD be specified as there is no uniform implementation of the
+            &quot;normal&quot; value at the time of this writing.</td>
           </tr>
 
           <tr>
@@ -1006,7 +1083,8 @@
           <tr>
             <td><code>#textAlign</code></td>
 
-            <td>MAY be used. The initial value of <code>tts:textAlign</code> SHALL be &quot;center&quot; for the default region, as defined in [[!TTML2]].</td>
+            <td>MAY be used. The initial value of <code>tts:textAlign</code> SHALL be &quot;center&quot; for the default region.
+            NOTE: This is consistent with [[ST2052-1]].</td>
           </tr>
 
           <tr>
@@ -1062,10 +1140,20 @@
 
             <td>MAY be used.</td>
           </tr>
+
+          <tr>
+            <th>Extension</th>
+
+            <th>Provisions</th>
+          </tr>
+
+          <tr>
+            <td><code>http://www.smpte-ra.org/schemas/2052-1/2010/smpte-tt#image</code></td>
+
+            <td>SHALL NOT be used.</td>
+          </tr>
         </tbody>
       </table>
-	  
-	        <p class='note'>The initial values specified for <code>tts:color</code>, <code>tts:displayAlign</code> are those specified by [[ST2052-1]].</p>
     </section>
   </section>
 
@@ -1073,20 +1161,25 @@
     <h2>Image Profile Constraints</h2>
 
     <section>
-      <h3>Profile Designator and Definition Document</h3>
-	  
-	  	    <p class='issue'>This Section is a placeholder and will be revisited based the outcome of the [[!TTML2]] profile discussions.</p>
-
-      <p>A subtitle document conforming to the Image Profile SHALL be associated with the following profile designator and profile
-      definition document:</p>
-      <pre>
-&lt;?xml version=&quot;1.0&quot; encoding=&quot;utf-8&quot;?&gt;
-&lt;profile designator=&quot;http://www.w3.org/ns/ttml/profile/imsc/image/designator&quot; xmlns=&quot;http://www.w3.org/ns/ttml#parameter&quot;&gt;
-  &lt;extensions&gt;
-    &lt;extension&gt;http://www.w3.org/ns/ttml/profile/definition/imsc/image/feature#all&lt;/extension&gt;
-  &lt;/extensions&gt;
-&lt;/profile&gt;
-</pre>
+      <h3>Profile Designator</h3>
+
+      <p>A subtitle document conforming to the Image Profile SHALL be associated with the following profile designator:</p>
+
+      <table class='simple'>
+        <tbody>
+          <tr>
+            <th>Profile Name</th>
+
+            <th>Profile Designator</th>
+          </tr>
+
+          <tr>
+            <td>IMSC Image</td>
+
+            <td><code>http://www.w3.org/ns/ttml/profile/imsc/image</code></td>
+          </tr>
+        </tbody>
+      </table>
     </section>
 
     <section>
@@ -1111,49 +1204,22 @@
       <h3><code>div</code> element</h3>
 
       <p>If a <code>tts:backgroundImage</code> attribute is applied to a <code>div</code> element, the width and height of the
-      region extent associated with the <code>div</code> element SHALL be specified and SHALL be equal to the width and height of the
-      image source referenced by the <code>tts:backgroundImage</code>.</p>
+      region extent associated with the <code>div</code> element SHALL be specified and SHALL be equal to the width and height of
+      the image source referenced by the <code>tts:backgroundImage</code>.</p>
     </section>
 
     <section>
       <h3>Features</h3>
 
-      <p class='issue'>The following assumes, but does not require, the porting of the [[ST2052-1]] <code>#backgroundImage</code>
-      features to [[!TTML2]]. See <a href="http://www.w3.org/AudioVideo/TT/tracker/issues/238">ISSUE-238</a>.</p>
-
-	  
-	   <p>The features included in a subtitle document SHALL conform to the Table below:</p>
+      <p>The features included in a subtitle document SHALL conform to the Table below:</p>
 
       <table class='simple'>
-        <thead>
+        <tbody>
           <tr>
             <th>Feature</th>
 
             <th>Provisions</th>
           </tr>
-        </thead>
-
-        <tbody>
-          <tr>
-            <td><code>#backgroundImage</code></td>
-
-            <td>MAY be used. The backgroundImage attribute SHALL reference a complete image that conforms to the PNG image coding
-            as specified in Sections 7.1.1.3 and 15.1 of [[!MHP]].<br>
-            If a pHYs chunk is present, it SHALL indicate square pixels. Note: If no pixel aspect ratio is carried, the default of
-            square pixels will be assumed.</td>
-          </tr>
-
-          <tr>
-            <td><code>#backgroundImageHorizontal</code></td>
-
-            <td>SHALL NOT be used. <code>#backgroundImage</code> remains available for use.</td>
-          </tr>
-
-          <tr>
-            <td><code>#backgroundImageVertical</code></td>
-
-            <td>SHALL NOT be used. <code>#backgroundImage</code> remains available for use.</td>
-          </tr>
 
           <tr>
             <td><code>#bidi</code></td>
@@ -1280,6 +1346,22 @@
 
             <td>SHALL NOT be used.</td>
           </tr>
+
+          <tr>
+            <th>Extension</th>
+
+            <th>Provisions</th>
+          </tr>
+
+          <tr>
+            <td><code>http://www.smpte-ra.org/schemas/2052-1/2010/smpte-tt#image</code></td>
+
+            <td><code>smpte:backgroundImage</code> MAY be used. The backgroundImage attribute SHALL reference a complete image that
+            conforms to the PNG image coding as specified in Sections 7.1.1.3 and 15.1 of [[!MHP]]. If a pHYs chunk is present, it
+            SHALL indicate square pixels. Note: If no pixel aspect ratio is carried, the default of square pixels is assumed.<br>
+            <code>smpte:backgroundImageHorizontal</code> and <code>smpte:backgroundImageVertical</code> SHALL NOT be used.<br>
+            <code>smpte:image</code> SHALL NOT be used.</td>
+          </tr>
         </tbody>
       </table>
     </section>
@@ -1462,11 +1544,11 @@
           <li>It is specified on the <code>region</code> layout element that defines the region.</li>
 
           <li>It is specified on a <code>div</code>, <code>p</code>, <code>span</code> or <code>br</code> content element that is
-          to be flowed into the region for presentation in the intermediate synchronic document (see [[!TTML2]] for more details on
+          to be flowed into the region for presentation in the intermediate synchronic document (see [[!TTML1]] for more details on
           when a content element is followed into a region).</li>
 
           <li>It is specified on a <code>set</code> animation element that is to be applied to content elements that are to be
-          flowed into the region for presentation in the intermediate synchronic document (see [[!TTML2]] for more details on when
+          flowed into the region for presentation in the intermediate synchronic document (see [[!TTML1]] for more details on when
           a <code>set</code> animation element is applied to content elements).</li>
         </ul>
 
@@ -1581,7 +1663,7 @@
           G<sub>n</sub> using the corresponding style information.</li>
         </ul>
 
-        <p>Two glyphs are identical if and only if the following [[!TTML2]] styles are identical:</p>
+        <p>Two glyphs are identical if and only if the following [[!TTML1]] styles are identical:</p>
 
         <ul>
           <li><code>tts:color</code></li>
@@ -1713,129 +1795,98 @@
     </section><!-- start CFF-TT 1.0.7 -->
 
     <section>
-      <h3>Layout Model</h3>
-
-      <section>
-        <h4>General</h4>
-
-        <p>The height and width of the area occupied by text within a region depend on line height as well as the width of, and
-        spacing between (kerning), individual glyphs. The following allows the area occupied by text to be precisely determined,
-        and thus region extent to be set such that text flows without clipping.</p>
-      </section>
-
-      <section>
-        <h4>Reference Fonts</h4>
-
-        <p>A glyph that matches one of the combinations of computed font family and code point listed in the table below SHALL be laid out using
-		metrics equal to the metrics of the specified reference font, unless the glyph is not defined by the
-        reference font.</p>
-
-        <table class='simple'>
-          <thead>
-            <tr>
-              <th>Computed Font Family</th>
-
-              <th>Code Points</th>
-
-              <th>Reference Font</th>
-            </tr>
-          </thead>
-
-          <tbody>
-            <tr>
-              <td>monospaceSerif</td>
-
-              <td>
-                All code points specified in <a href="#recommended-unicode-code-points-per-language"></a>
-              </td>
-
-              <td>
-                <a href=
-                "http://www.microsoft.com/typography/fonts/family.aspx?FID=10">http://www.microsoft.com/typography/fonts/family.aspx?FID=10</a>
-                (Courier New)
-              </td>
-            </tr>
-
-            <tr>
-              <td>proportionalSansSerif</td>
-
-              <td>
-                All code points specified in <a href="#recommended-unicode-code-points-per-language"></a>, excluding the code
-                points defined for Semitic languages alone.
-              </td>
-
-              <td>
-                <a href=
-                "http://www.microsoft.com/typography/fonts/family.aspx?FID=8">http://www.microsoft.com/typography/fonts/family.aspx?FID=8</a>
-                (Arial) or <a href=
-                "http://www.linotype.com/en/526/Helvetica-family.html">http://www.linotype.com/en/526/Helvetica-family.html</a>
-                (Helvetica)
-              </td>
-            </tr>
-          </tbody>
-        </table>
-
-        <p class="note">Implementations can use use fonts other than those specified above. Two fonts with equal metrics can have a
-        different appearance, but flow identically.</p>
-
-        <p class="note">proportionalSansSerif is not used in practice for Hebrew and Arabic captions and subtitles.</p>
-      </section>
-
-      <section>
-        <h4>Line Height and Centering</h4>
-
-        <p>The computed value of <code>tts:lineHeight</code> shall be equal to 120% if tts:lineHeight=&quot;normal&quot;.</p>
-
-        <p><code>tts:lineHeight</code> values expressed using the percentage metric shall be relative to the largest font size on
-        the line.</p>
-
-        <aside class="example">
-          Assuming that the root container is ultimately rendered at a 1920×1080 resolution and
-          <code>tts:lineHeight</code>=&quot;100%&quot;, a line mixing glyphs with font size of &quot;10px&quot;, &quot;36px&quot;
-          and &quot;1c&quot; has a computed value of <code>tts:lineHeight</code> equal to &quot;72px&quot;.
-        </aside>
-
-        <p>If the computed value of <code>tts:lineHeight</code> is not supported, then a presentation processor SHALL use the next
-        highest supported value.</p>
-
-        <aside class="example">
-          Three lines of 12px characters with <code>tts:lineHeight</code>=&quot;normal&quot; has a height of 45px = ⌈12px *
-          120%⌉ × 3 assuming line heights have 1px resolution.
-        </aside>
-
-        <p>White space in excess of the largest font size on the line SHALL be allocated evenly top and bottom (half-leading). Note
-        that inter-baseline separation includes any leading.</p><!-- end CFF-TT 1.0.7 -->
-
-        <p class="note">Since font size can change on a line and text can wrap, it is necessary to first determine the glyphs
-        present on a line before determining line height.</p>
-
-        <p class="note">Glyphs that do not extend beyond the specific <code>tts:fontSize</code> value will not clip top or
-        bottom.</p>
-      </section>
+      <h3>Reference Fonts</h3>
+
+      <p>The height and width of the area occupied by text within a region depend on line height as well as the width of, and
+      spacing between (kerning), individual glyphs. The following allows the area occupied by text to be closely determined, and
+      thus the region extent to be set such that text flows without clipping.</p>
+
+      <p>A glyph that matches one of the combinations of computed font family and code point listed in the table below SHALL be
+      laid out using metrics equal to the metrics of the specified reference font, unless the glyph is not defined by the reference
+      font.</p>
+
+      <table class='simple'>
+        <thead>
+          <tr>
+            <th>Computed Font Family</th>
+
+            <th>Code Points</th>
+
+            <th>Reference Font</th>
+          </tr>
+        </thead>
+
+        <tbody>
+          <tr>
+            <td>monospaceSerif</td>
+
+            <td>
+              All code points specified in <a href="#recommended-unicode-code-points-per-language"></a>
+            </td>
+
+            <td>
+              <a href=
+              "http://www.microsoft.com/typography/fonts/family.aspx?FID=10">http://www.microsoft.com/typography/fonts/family.aspx?FID=10</a>
+              (Courier New)
+            </td>
+          </tr>
+
+          <tr>
+            <td>proportionalSansSerif</td>
+
+            <td>
+              All code points specified in <a href="#recommended-unicode-code-points-per-language"></a>, excluding the code points
+              defined for Semitic languages alone.
+            </td>
+
+            <td>
+              <a href=
+              "http://www.microsoft.com/typography/fonts/family.aspx?FID=8">http://www.microsoft.com/typography/fonts/family.aspx?FID=8</a>
+              (Arial) or <a href=
+              "http://www.linotype.com/en/526/Helvetica-family.html">http://www.linotype.com/en/526/Helvetica-family.html</a>
+              (Helvetica)
+            </td>
+          </tr>
+        </tbody>
+      </table>
+
+      <p class="note">Implementations can use use fonts other than those specified above. Two fonts with equal metrics can have a
+      different appearance, but flow identically.</p>
+
+      <p class="note">proportionalSansSerif is not used in practice for Hebrew and Arabic captions and subtitles.</p>
     </section>
   </section>
 
   <section class='appendix'>
     <h2>Recommended Character Sets</h2>
-	
-	
-	<p>When authoring textual content, authors are encouraged to select from sets of characters based on the language expressed using the xml:lang. The idea is to increase the confidence that the text will be presented correctly by implementations targeting specific locales.</p>
-
-	<p>Specifically, for a given language, an author should choose characters from the set resulting from the union of the following sets:
-          <li>the main and punctuation exemplar character sets specified for the language in [[CLDR]]; and</li>
-          <li>the digits and symbols included in all numberSystems specified for the language in [[CLDR]]; and</li>
-          <li>the common character set specified in Table 1; and</li>
-          <li>supplementary characters specified for the language in Table 2, if any</li>
-        </ul>
-	</p>
-	
-<p>Some of these sets may overlap.</p>
-
-<p>Table 1 captures the set of characters intended to be available to authors across all languages.
-The terms used in the table are defined in [[!UNICODE]].</p>
+
+    <p>When authoring textual content, authors are encouraged to select from sets of characters based on the language expressed
+    using the xml:lang. The idea is to increase the confidence that the text will be presented correctly by implementations
+    targeting specific locales.</p>
+
+    <p>Specifically, for a given language, an author should choose characters from the set resulting from the union of the
+    following sets:</p>
+
+    <ul>
+      <li>the main and punctuation exemplar character sets specified for the language in [[CLDR]]; and</li>
+
+      <li>the digits and symbols included in all numberSystems specified for the language in [[CLDR]]; and</li>
+
+      <li>the common character set specified in Table 1; and</li>
+
+      <li>supplementary characters specified for the language in Table 2, if any</li>
+    </ul>
+
+    <p>Some of these sets may overlap.</p>
+
+    <p>Table 1 captures the set of characters intended to be available to authors across all languages. The terms used in the table
+    are defined in [[!UNICODE]].</p>
 
     <table class='simple'>
-	<caption>Table 1. Common Character Set.</caption>
+      <caption>
+        Table 1. Common Character Set.
+      </caption>
+
       <tr>
         <th>(Basic Latin)</th>
       </tr>
@@ -1867,8 +1918,8 @@
       <tr>
         <td>U+00A0 - U+00FF</td>
       </tr>
-	  
-	  <tr>
+
+      <tr>
         <th>(Number Forms)</th>
       </tr>
 
@@ -1907,8 +1958,8 @@
       <tr>
         <td>U+017E : LATIN SMALL LETTER Z WITH CARON</td>
       </tr>
-	  
-	  <tr>
+
+      <tr>
         <th>(Box Drawing)</th>
       </tr>
 
@@ -1943,8 +1994,8 @@
       <tr>
         <td>U+0192 : LATIN SMALL LETTER F WITH HOOK</td>
       </tr>
-	  
-	 <tr>
+
+      <tr>
         <th>(Block Elements)</th>
       </tr>
 
@@ -1959,7 +2010,8 @@
       <tr>
         <td>U+02DC : SMALL TILDE</td>
       </tr>
-	        <tr>
+
+      <tr>
         <th>(Geometric Shapes)</th>
       </tr>
 
@@ -1982,8 +2034,8 @@
       <tr>
         <td>U+2030 - U+203A : General punctuation</td>
       </tr>
-	  
-	        <tr>
+
+      <tr>
         <th>(Musical Symbols)</th>
       </tr>
 
@@ -2006,17 +2058,18 @@
       <tr>
         <td>U+20AC : EURO SIGN</td>
       </tr>
-    </table>
-
-	<br>
-	<p>
-	Table 2 specifies supplementary character set that have proven useful in captioning and subtitling applications for a number of selected languages. Table 2 is non-exhaustive, and will be extended as needs arise.</p>
-	
+    </table><br>
+
+    <p>Table 2 specifies supplementary character set that have proven useful in captioning and subtitling applications for a number
+    of selected languages. Table 2 is non-exhaustive, and will be extended as needs arise.</p>
+
     <table class='simple'>
-	<caption>Table 2. Supplementary Character Sets.</caption>
+      <caption>
+        Table 2. Supplementary Character Sets.
+      </caption>
+
       <thead>
         <tr>
-
           <th>Primary language subtag</th>
 
           <th>Characters</th>
@@ -2024,56 +2077,42 @@
       </thead>
 
       <tbody>
-
-
-		<tr>
-
+        <tr>
           <td>lv, lt, et, tr, hr, cs, pl, sl, sk</td>
 
-          <td>
-          (Latin Extended-A)<br>
+          <td>(Latin Extended-A)<br>
           U+0100 – U+017F</td>
         </tr>
-		
-		<tr>
-
+
+        <tr>
           <td>nl</td>
 
-          <td>
-           (Combining Diacritical Marks)<br>
+          <td>(Combining Diacritical Marks)<br>
           U+0301</td>
-
         </tr>
-		
-				<tr>
-
+
+        <tr>
           <td>ro</td>
 
-          <td>
-          (Latin Extended-A)<br>
+          <td>(Latin Extended-A)<br>
           U+0100 – U+017F<br>
-		  (Latin Extended-B)<br>
-		  U+0218 – U+0219<br>
-U+021A – U+021B
+          (Latin Extended-B)<br>
+          U+0218 – U+0219<br>
+          U+021A – U+021B</td>
         </tr>
-		
-	
-
+
+        <tr>
           <td>el</td>
 
-          <td>
-		  (Combining Diacritical Marks)<br>
-		  U+0301<br>
-		U+0308<br>
+          <td>(Combining Diacritical Marks)<br>
+          U+0301<br>
+          U+0308<br>
           (Greek and Coptic)<br>
           U+0386 – U+0387<br>
-          U+0388 – U+03CE 
-		  </td>
+          U+0388 – U+03CE</td>
         </tr>
 
-
         <tr>
-
           <td>pt, es</td>
 
           <td>(Currency symbols)<br>
@@ -2081,114 +2120,127 @@
           U+20B3</td>
         </tr>
 
-
-
         <tr>
           <td>ar</td>
 
-          <td>
-		  (Arabic)<br>
+          <td>(Arabic)<br>
           U+060C – U+060D<br>
           U+061B<br>
           U+061E – U+061F<br>
           U+0621 – U+063A<br>
           U+0640 – U+0652<br>
           U+0660 – U+066D<br>
-		  U+0670<br>
-		  </td>
+          U+0670<br></td>
         </tr>
 
         <tr>
           <td>he</td>
 
-          <td>
-          (Hebrew)<br>
+          <td>(Hebrew)<br>
           U+05B0 – U+05C3<br>
           U+05D0 – U+05EA<br>
           U+05F3 – U+05F4</td>
         </tr>
 
-
-
-
         <tr>
-
           <td>bs, bg, mk, ru, sr</td>
 
-          <td>
-          (Latin Extended-A)<br>
+          <td>(Latin Extended-A)<br>
           U+0100 – U+017F<br>
           (Cyrillic)<br>
           U+0400 – U+045F</td>
         </tr>
 
         <tr>
-
           <td>uk</td>
 
-          <td>
-          (Latin Extended-A)<br>
-          U+0100 – U+017F<br>
-          (Cyrillic)<br>
-          U+0400 – U+045F<br>	
-		  			U+0490 – U+0491<br>
-		  (Spacing Modifier Letters)<br>
-		  U+02BC<br>
-(Letterlike Symbols)<br>
-		U+2116
-
-		  
-		  
-		  </td>
-        </tr>
-
-
-
-
-        <tr>
-
-          <td>kk</td>
-
-          <td>
-		   (Latin Extended-A)<br>
+          <td>(Latin Extended-A)<br>
           U+0100 – U+017F<br>
           (Cyrillic)<br>
           U+0400 – U+045F<br>
-		  U+0492 – U+0493<br>
-			U+049A – U+049B<br>
-			U+04A2 – U+04A3<br>
-			U+04AE – U+04B1<br>
-			U+04BA – U+04BB<br>
-			U+04D8 – U+04D9<br>
-			U+04E8 – U+04E9<br>
-
-		  
-		  
-		  
-		  </td>
+          U+0490 – U+0491<br>
+          (Spacing Modifier Letters)<br>
+          U+02BC<br>
+          (Letterlike Symbols)<br>
+          U+2116</td>
         </tr>
 
         <tr>
-
+          <td>kk</td>
+
+          <td>(Latin Extended-A)<br>
+          U+0100 – U+017F<br>
+          (Cyrillic)<br>
+          U+0400 – U+045F<br>
+          U+0492 – U+0493<br>
+          U+049A – U+049B<br>
+          U+04A2 – U+04A3<br>
+          U+04AE – U+04B1<br>
+          U+04BA – U+04BB<br>
+          U+04D8 – U+04D9<br>
+          U+04E8 – U+04E9<br></td>
+        </tr>
+
+        <tr>
           <td>hu</td>
 
-          <td>
-          (Latin Extended-A)<br>
+          <td>(Latin Extended-A)<br>
           U+0100 – U+017F<br>
-		  (General Punctuation)<br>
-		  U+2052<br>
-		  (Miscellaneous Mathematical Symbols-A)<br>
-U+27E8–U+27E9
-</td>
+          (General Punctuation)<br>
+          U+2052<br>
+          (Miscellaneous Mathematical Symbols-A)<br>
+          U+27E8–U+27E9</td>
         </tr>
       </tbody>
     </table>
   </section>
 
   <section class='appendix'>
-    <h2>Schema</h2>
-
-    <p><em>TBD</em></p>
+    <h2>Extensions</h2>
+
+    <section class='appendix'>
+      <h3>General</h3>
+
+      <p>The following sections define extension designations, expressed as relative URIs (fragment identifiers) with respect to
+      the TT Extension Namespace base URI (see [[!TTML1]].</p>
+    </section>
+
+    <section class='appendix'>
+      <h3>#progressivelyDecodable</h3>
+
+      <p>A TTML transformation processor supports the <code>#progressivelyDecodable</code> feature if it recognizes and is capable
+      of transforming values of the <a href="#h3_ttp-progressivelydecodable"><code>ttp:progressivelyDecodable</code></a>.</p>
+
+      <p>A TTML presentation processor supports the <code>#progressivelyDecodable</code> feature if it implements presentation
+      semantic support for values of the <a href="#h3_ttp-progressivelydecodable"><code>ttp:progressivelyDecodable</code></a>
+      attribute.</p>
+    </section>
+
+    <section class='appendix'>
+      <h3>#aspectRatio</h3>
+
+      <p>A TTML transformation processor supports the <code>#aspectRatio</code> feature if it recognizes and is capable of
+      transforming values of the <a href="#h3_ttp-aspectratio"><code>ttp:aspectRatio</code></a>.</p>
+
+      <p>A TTML presentation processor supports the <code>#aspectRatio</code> feature if it implements presentation semantic
+      support for values of the <a href="#h3_ttp-aspectratio"><code>ttp:aspectRatio</code></a> attribute.</p>
+    </section>
+
+    <section class='appendix'>
+      <h3>#forcedDisplay</h3>
+
+      <p>A TTML transformation processor supports the <code>#forcedDisplay</code> feature if it recognizes and is capable of
+      transforming values of the <a href="#h3_tts-forceddisplay"><code>tts:forcedDisplay</code></a>.</p>
+
+      <p>A TTML presentation processor supports the <code>#forcedDisplay</code> feature if it implements presentation semantic
+      support for values of the <a href="#h3_tts-forceddisplay"><code>tts:forcedDisplay</code></a> attribute.</p>
+    </section>
+
+    <section class='appendix'>
+      <h3>http://www.smpte-ra.org/schemas/2052-1/2010/smpte-tt#image</h3>
+
+      <p>The <code>http://www.smpte-ra.org/schemas/2052-1/2010/smpte-tt#image</code> extension is specified in [[ST2052-1]].</p>
+    </section>
   </section>
 </body>
 </html>