--- a/ttml2/spec/ttml2-changes.html	Sun Jan 11 19:05:59 2015 -0700
+++ b/ttml2/spec/ttml2-changes.html	Wed Jan 14 09:45:15 2015 -0700
@@ -375,41 +375,33 @@
 * In 14.1.1, extend content model of 'metadata' to permit the use of
   embedded content 'data' element children.
 
-* In Appendix B, update referenced schemas to reflect new/changed vocabulary
+* In Appendix A, upgrade material on concrete encoding to normative,
+  (previously in Appendix O of TTML1).
+
+* In Appendix A, add missing ' and " character entities.
+
+* In Appendix C, update referenced schemas to reflect new/changed vocabulary
   definitions.
 
-* In Appendix C, replace former content specifying media type registration
-  (no longer needed since registration already occurred in TTML1 context)
-  with new (unrelated) material defining TTML ISD and ISD Sequence Formats.
-
-* In Appendix D, add #border, #textOrientation, and #version feature
+* In Appendix E, add #border, #textOrientation, and #version feature
   designators.
 
-* In Appendix F, define only newly introduced TTML2 profiles.
+* In Appendix G, define only newly introduced TTML2 profiles.
 
-* In Appendix F, add #border, #textOrientation, and #version feature
+* In Appendix G, add #border, #textOrientation, and #version feature
   designators in standard profiles.
 
-* In Appendix G, add (normative) reference to RFC2396 (URI).
+* In Appendix J, add (normative) reference to RFC2396 (URI).
 
-* In Appendix G, add (normative) reference to Ruby Annotations REC.
+* In Appendix J, add (normative) reference to Ruby Annotations REC.
 
-* In Appendix G, add (normative) reference to CSS Ruby Draft.
+* In Appendix J, add (normative) reference to CSS Ruby Draft.
 
-* In Appendix G, move SVG1.1 reference from Appendix H and update to Second
+* In Appendix J, move SVG1.1 reference from Appendix H and update to Second
   Edition.
 
-* In Appendix O, change appendix designation to normative, effectively
-  changing the informative concrete encoding recommendation to a normative
-  recommendation.
-
-* In Appendix M, change appendix designation to normative, effectively making
-  the concrete encoding semantics normatively applicable.
-
-* In Appendix M, add missing ' and " character entities.
-
-* In Appendix N, change appendix designation to normative, effectively making
-  the time expression semantics normatively applicable.
+* In Appendix H, upgrade material on time expression semantics to normative,
+  (previously in Appendix N of TTML1).
 
 <span class="strong">Editorial Changes</span>
 
@@ -520,23 +512,26 @@
 
 * In 14.1, reorder ttm:* attribute sub-sections to be alphabetic.
 
-* In Appendix H, add (non-normative) reference to CSS Writing Modes Level 3.
+* Reorder (and relabel) appendices to maintain normative appendices followed by
+  non-normative appendices.
 
-* In Appendix H, add (non-normative) reference to Japanese Language Requirements
+* In Appendix K, add (non-normative) reference to CSS Writing Modes Level 3.
+
+* In Appendix K, add (non-normative) reference to Japanese Language Requirements
   (JLREQ).
 
-* In Appendix H, add (non-normative) reference to original Namespaces in XML
+* In Appendix K, add (non-normative) reference to original Namespaces in XML
   REC (NSOriginal).
 
-* In Appendix H, add (non-normative) reference to SDP US.
-
-* In Appendix H, add (non-normative) reference to TTML1.
+* In Appendix K, add (non-normative) reference to SDP US.
 
-* In Appendix H, update SMIL reference to SMIL3.0.
+* In Appendix K, add (non-normative) reference to TTML1.
 
-* In Appendix J, add derivation of tt:animate and tt:animation elements.
+* In Appendix K, update SMIL reference to SMIL3.0.
 
-* In Appendix J, add derivation of tts:border and tts:textOrientation
+* In Appendix M, add derivation of tt:animate and tt:animation elements.
+
+* In Appendix M, add derivation of tts:border and tts:textOrientation
   attributes.
 
 * Change convention for labeling and citing definitions to use "[lower case]"
@@ -546,8 +541,6 @@
 
 * Insert informative Appendix P to contain considerations about CEA708
   mapping.
-
-* Relabel Appendix P to Appendix Q, having inserted new Appendix P.
 </pre>
 </div>
 </div>

--- a/ttml2/spec/ttml2.xml	Sun Jan 11 19:05:59 2015 -0700
+++ b/ttml2/spec/ttml2.xml	Wed Jan 14 09:45:15 2015 -0700
@@ -1820,6 +1820,11 @@
 specifications, all required attributes are present, and the declared
 value of each attribute satisfies the type declared by the
 associated <loc href="#terms-abstract-document-type">abstract document type</loc>.</p>
+<issue id="issue-362">
+<head>Attribute Forward Compabitility</head>
+<source><loc href="http://www.w3.org/AudioVideo/TT/tracker/issues/362">http://www.w3.org/AudioVideo/TT/tracker/issues/362</loc></source>
+<p>Enhance step (3) to handle forward compatibility of new attributes introduced into TT namespaces.</p>
+</issue>
 <note>
 <p>While a conformant processor may not <emph>a priori</emph> reject a
 conformant <loc href="#terms-document-instance">document instance</loc>, a given <loc href="#terms-document-instance">document instance</loc> may be
@@ -4500,6 +4505,11 @@
 <p>The <att>ttp:frameRate</att> attribute is used to specify the frame rate of a related
 media object or the intrinsic frame rate of a <loc href="#terms-document-instance">document instance</loc> in case it is intended
 to function as an independent media object.</p>
+<issue id="issue-333">
+<head>Defaulting Frame Rate Multiplier, Sub Frame Rate</head>
+<source><loc href="http://www.w3.org/AudioVideo/TT/tracker/issues/333">http://www.w3.org/AudioVideo/TT/tracker/issues/333</loc></source>
+<p>If frame rate is defaulted to processing environment, then frame rate multiplier and sub frame rate should be as well.</p>
+</issue>
 <p>If specified, the value of this attribute must adhere to the following syntax:</p>
 <table id="parameter-attribute-frameRate-syntax" role="syntax">
 <caption>Syntax Representation &ndash; ttp:frameRate</caption>
@@ -4725,6 +4735,19 @@
 <loc href="#time-expression-semantics-media">Media Time Base</loc>
 or a <loc href="#time-expression-semantics-smpte">SMPTE Time Base</loc>. It does not apply and
 must not be specified when operating in a <loc href="#time-expression-semantics-clock">Clock Time Base</loc>.</p>
+<issue id="issue-270">
+<head>Media Time Offset</head>
+<source><loc href="http://www.w3.org/AudioVideo/TT/tracker/issues/270">http://www.w3.org/AudioVideo/TT/tracker/issues/270</loc></source>
+<p>Tie up loose ends with respect to definition of media time offset, particulary regarding the definition of the origin and beginning of
+the document temporal extent.</p>
+</issue>
+<p></p>
+<issue id="issue-335">
+<head>Media Time Offset</head>
+<source><loc href="http://www.w3.org/AudioVideo/TT/tracker/issues/335">http://www.w3.org/AudioVideo/TT/tracker/issues/335</loc></source>
+<p>Tie up loose ends with respect to definition of media time offset, particulary regarding the definition of the origin and beginning of
+the document temporal extent.</p>
+</issue>
 <p>If specified, the value of this attribute must adhere to the following syntax:</p>
 <table id="parameter-attribute-mediaOffset-syntax" role="syntax">
 <caption>Syntax Representation &ndash; ttp:mediaOffset</caption>
@@ -4789,6 +4812,12 @@
 <head>ttp:storageAspectRatio</head>
 <p>The <att>ttp:storageAspectRatio</att> attribute may be used to express the <loc href="#terms-storage-aspect-ratio">storage aspect ratio</loc> associated with the
 <loc href="#terms-authoring-viewport">authoring viewport</loc>.</p>
+<issue id="issue-201">
+<head>Maintaining Display Aspect Ratio</head>
+<source><loc href="http://www.w3.org/AudioVideo/TT/tracker/issues/201">http://www.w3.org/AudioVideo/TT/tracker/issues/201</loc></source>
+<p>Tie up loose ends with respect to support for retaining display aspect ratio. See also new values of <loc href="#style-attribute-extent"><att>tts:extent</att></loc>:
+<code>contain</code> and <code>cover</code>.</p>
+</issue>
 <p>If specified, the value of this attribute must adhere to the following syntax:</p>
 <table id="parameter-attribute-storageAspectRatio-syntax" role="syntax">
 <caption>Syntax Representation &ndash; ttp:storageAspectRatio</caption>
@@ -7376,6 +7405,11 @@
 <head>tts:backgroundColor</head>
 <p>The <att>tts:backgroundColor</att> attribute is used to specify a style property that
 defines the background color of a region or an area generated by content flowed into a region.</p>
+<issue id="issue-302">
+<head>Line Area Background Height</head>
+<source><loc href="http://www.w3.org/AudioVideo/TT/tracker/issues/302">http://www.w3.org/AudioVideo/TT/tracker/issues/302</loc></source>
+<p>Fix definition of block progression dimension of background area of a line area. Neither XSL-FO nor CSS are sufficiently precise.</p>
+</issue>
 <p>This attribute may be specified by any
 element type
 that permits use of attributes in the TT Style Namespace; however, this attribute applies
@@ -8167,6 +8201,11 @@
 <head>tts:displayAlign</head>
 <p>The <att>tts:displayAlign</att> attribute is used to specify a style property that
 defines the alignment of block areas in the block progression direction.</p>
+<ednote>
+<name>Justification in Block Progression Dimension</name>
+<date>2015-01-14</date>
+<edtext>Add <code>justify</code> value to support justification in block progression dimension.</edtext>
+</ednote>
 <p>This attribute may be specified by any
 element type
 that permits use of attributes in the TT Style Namespace; however, this attribute applies
@@ -9181,6 +9220,11 @@
 <head>tts:lineHeight</head>
 <p>The <att>tts:lineHeight</att> attribute is used to specify a style property that
 defines the inter-baseline separation between line areas generated by content flowed into a region.</p>
+<issue id="issue-284">
+<head>Normal Line Height Multiplier</head>
+<source><loc href="https://www.w3.org/AudioVideo/TT/tracker/issues/284">https://www.w3.org/AudioVideo/TT/tracker/issues/284</loc></source>
+<p>Re-visit choice of 120% versus 125% for multiplier used in interpreting <code>normal</code> line height.</p>
+</issue>
 <p>This attribute may be specified by any
 element type
 that permits use of attributes in the TT Style Namespace; however, this attribute applies
@@ -9909,8 +9953,8 @@
 </table>
 <p></p>
 <ednote>
-<name>Border Example Image</name>
-<date>2011-11-28</date>
+<name>Position Example Image</name>
+<date>2014-11-28</date>
 <edtext>Insert image of position example.</edtext>
 </ednote>
 <!--
@@ -10366,6 +10410,11 @@
 <head>tts:rubyPosition</head>
 <p>The <att>tts:rubyPosition</att> attribute is used to specify the position of ruby text in the block progression dimension
 with respect to its associated ruby base.</p>
+<ednote>
+<name>Outside Annotations</name>
+<date>2015-01-14</date>
+<edtext>Add <code>auto</code> and <code>outside</code> values as defined by &lt;emphasisPosition&gt; expressions.</edtext>
+</ednote>
 <p>This attribute may be specified by any element type that permits use of attributes in the TT Style Namespace; however,
 this attribute applies as a style property only to those element types indicated in the following table.</p>
 <table id="style-property-details-rubyPosition" role="common">
@@ -12381,6 +12430,11 @@
 <p>The semantics of
 the unit of measure <code>px</code> (pixel) 
 are as defined by <bibref ref="xsl11"/>, &sect; 5.9.13.</p>
+<issue id="issue-179">
+<head>Definition of Pixel</head>
+<source><loc href="http://www.w3.org/AudioVideo/TT/tracker/issues/179">http://www.w3.org/AudioVideo/TT/tracker/issues/179</loc></source>
+<p>Replace unworkable (and unadopted) definition of pixel with an appropriate definition based on units of some viewport coordinate space.</p>
+</issue>
 <p>When specified relative to a font whose size is expressed as a single length
 measure or as two length measures of equal length, the unit of measure <code>em</code> is considered to be
 identical to that defined by <bibref ref="xsl11"/>, &sect; 5.9.13;
@@ -13879,6 +13933,11 @@
 </div2> <!-- layout-attribute-vocabulary -->
 <div2 id="semantics-layout">
 <head>Layout Semantics</head>
+<issue id="issue-365">
+<head>HTML Mapping</head>
+<source><loc href="https://www.w3.org/AudioVideo/TT/tracker/issues/365">https://www.w3.org/AudioVideo/TT/tracker/issues/365</loc></source>
+<p>Define HTML5 mapping while separating ISD generation from follow-on mappings.</p>
+</issue>
 <div3 id="semantics-region-layout">
 <head>Region Layout and Presentation</head>
 <p>This section defines the semantics of region layout and
@@ -13998,7 +14057,7 @@
 <p>perform procedure <phrase role="strong"><loc href="#procedure-generate-inline-regions">[generate inline regions]</loc></phrase>;</p>
 </item>
 <item>
-<p>perform procedure <phrase role="strong"><loc href="procedure-generate-out-of-line-regions">[generate out-of-line regions]</loc></phrase>;</p>
+<p>perform procedure <phrase role="strong"><loc href="#procedure-generate-out-of-line-regions">[generate out-of-line regions]</loc></phrase>;</p>
 </item>
 </olist>
 </def>
@@ -14131,6 +14190,11 @@
 <p>remove <emph>R</emph> from the <code>[children]</code> information item property of <emph>B</emph>;</p>
 </item>
 </olist>
+<issue id="issue-324">
+<head>Duration Restrictions</head>
+<source><loc href="http://www.w3.org/AudioVideo/TT/tracker/issues/324">http://www.w3.org/AudioVideo/TT/tracker/issues/324</loc></source>
+<p>Handle case where use of <code>dur</code> is not permitted, e.g., when using discontinuous SMPTE time base.</p>
+</issue>
 </def>
 </gitem>
 </glist>
@@ -14284,6 +14348,12 @@
 <label>[associate region]</label>
 <def>
 <p></p>
+<issue id="issue-341">
+<head>Multiple Descendant Region Ambiguitty</head>
+<source><loc href="http://www.w3.org/AudioVideo/TT/tracker/issues/341">http://www.w3.org/AudioVideo/TT/tracker/issues/341</loc></source>
+<p>Refine step (3) to resolve ambiguity when multiple regions are referenced by descendants.</p>
+</issue>
+<p></p>
 <ednote>
 <name>Inline Region Association</name>
 <date>2013-08-28</date>
@@ -14755,6 +14825,12 @@
 <specref ref="parameter-attribute-timeBase"/> for further information on
 explicit specification of frame rate, sub-frame rate, tick rate, and time base.</p>
 </note>
+<issue id="issue-293">
+<head>Dates in Time Expressions</head>
+<source><loc href="http://www.w3.org/AudioVideo/TT/tracker/issues/293">http://www.w3.org/AudioVideo/TT/tracker/issues/293</loc></source>
+<p>Consider adding dates to time expressions to handle issues around midnight crossings and related use cases.</p>
+</issue>
+<p></p>
 <table id="timeExpression-syntax" role="syntax">
 <caption>Syntax Representation &ndash; &lt;timeExpression&gt;</caption>
 <tbody>
@@ -14835,6 +14911,11 @@
 <bibref ref="smil3"/> apply to the interpretation of like-named timed elements and timing
 vocabulary defined by this specification, given the following
 constraints:</p>
+<issue id="issue-338">
+<head>Implicit Duration of Singleton Span</head>
+<source><loc href="http://www.w3.org/AudioVideo/TT/tracker/issues/338">http://www.w3.org/AudioVideo/TT/tracker/issues/338</loc></source>
+<p>Refine definition implicit duration of singleton span in a sequential container.</p>
+</issue>
 <ulist>
 <item>
 <p>The implicit duration of an anonymous span is defined as follows: if
@@ -14907,6 +14988,11 @@
 <div3 id="animation-vocabulary-animate">
 <head>animate</head>
 <p>The <el>animate</el> element expresses a series of changes (animations) to be applied (targeted) to one or more style property attributes of associated elements.</p>
+<issue id="issue-355">
+<head>Marquee</head>
+<source><loc href="http://www.w3.org/AudioVideo/TT/tracker/issues/355">http://www.w3.org/AudioVideo/TT/tracker/issues/355</loc></source>
+<p>Consider whether semantics of ARIB-TT's marquee extension can be handled by <code>animate</code>, and, if not, then consider extending.</p>
+</issue>
 <p>An <el>animate</el> element may appear as either (1) a child of a
 <loc href="#terms-content-element">content element</loc> or a <loc href="#layout-vocabulary-region"><el>region</el></loc> element,
 referred to as <loc href="#terms-inline-animation">inline animation</loc>, or
@@ -15958,6 +16044,17 @@
 <item><p><specref ref="metadata-attribute-agent"/></p></item>
 <item><p><specref ref="metadata-attribute-role"/></p></item>
 </ulist>
+<issue id="issue-358">
+<head>Document Sequencing</head>
+<source><loc href="http://www.w3.org/AudioVideo/TT/tracker/issues/358">http://www.w3.org/AudioVideo/TT/tracker/issues/358</loc></source>
+<p>Add <code>ttm:sequenceIdentifier</code> or <code>ttm:sequenceNumber</code> or both if unavoidable.</p>
+</issue>
+<p></p>
+<issue id="issue-361">
+<head>Media Timestamp Correlation</head>
+<source><loc href="http://www.w3.org/AudioVideo/TT/tracker/issues/361">http://www.w3.org/AudioVideo/TT/tracker/issues/361</loc></source>
+<p>Add <code>ttm:mediaTimestamp</code> to support media synchronization.</p>
+</issue>
 <note role="explanation">
 <p>Only certain metadata item attributes may be used with <loc href="#terms-content-element">content element</loc>. See
 the definitions of <loc href="#terms-content-element">content elements</loc> to determine permissible usage.</p>
@@ -15983,6 +16080,11 @@
 to express
 the roles, functions, or characteristics
 of some <loc href="#terms-content-element">content element</loc> that is so labeled.</p>
+<issue id="issue-25">
+<head>Parameterized Roles</head>
+<source><loc href="http://www.w3.org/AudioVideo/TT/tracker/issues/25">http://www.w3.org/AudioVideo/TT/tracker/issues/25</loc></source>
+<p>Consider supporting parameterized roles to increase CEA 708 interoperability.</p>
+</issue>
 <p>If specified, the value of this attribute must adhere to the following
 syntax, where
 the syntactic element <emph>S</emph> must adhere to production
@@ -16132,6 +16234,12 @@
 </tbody>
 </table>
 <p></p>
+<issue id="issue-328">
+<head>Alternate Text Metadata</head>
+<source><loc href="http://www.w3.org/AudioVideo/TT/tracker/issues/328">http://www.w3.org/AudioVideo/TT/tracker/issues/328</loc></source>
+<p>Add named item to handle <code>ittm:altText</code>.</p>
+</issue>
+<p></p>
 <ednote>
 <name>Elaborate Named Items</name>
 <date>2014-11-26</date>
@@ -16408,6 +16516,21 @@
 </div1> <!-- metadata -->
 </body>
 <back>
+<div1 id="concrete-encoding">
+<head>Concrete Encoding</head>
+<p><emph>This appendix is normative.</emph></p>
+<p>In the absence of other requirements, a <loc href="#terms-document-instance">document instance</loc> should be concretely encoded as a
+well-formed XML 1.0 <bibref ref="xml10"/> document using the UTF-8 character encoding.</p>
+<note role="elaboration">
+<p>When using XML 1.0 <bibref ref="xml10"/> as the concrete encoding of TTML, only the following named character entities are defined:
+<code>&amp;amp;</code>, <code>&amp;apos;</code>, <code>&amp;gt;</code>, <code>&amp;lt;</code>, and <code>&amp;quot;</code>.</p>
+</note>
+<issue id="issue-360">
+<head>Support Content Encoding</head>
+<source><loc href="http://www.w3.org/AudioVideo/TT/tracker/issues/360">http://www.w3.org/AudioVideo/TT/tracker/issues/360</loc></source>
+<p>Specify preference to use of gzip content encoding for compressed delivery in the case that client indicates it accepts encoding.</p>
+</issue>
+</div1>
 <div1 id="reduced-infoset">
 <head>Reduced XML Infoset</head>
 <p><emph>This appendix is normative.</emph></p>
@@ -16487,297 +16610,20 @@
 is defined by <specref ref="conformance-content"/>.</p>
 </div2>
 </div1>
-<div1 id="isd">
-<head>Intermediate Document Syntax</head>
+<div1 id="media-types-registration">
+<head>Media Type Registration</head>
 <p><emph>This appendix is normative.</emph></p>
-<p>This appendix specifies the syntactic elements and structure of a
-<loc href="#terms-timed-text-intermediate-document">timed text intermediate document</loc>.
-An ISD instance may be represented as a standalone document instance or
-in a collection represented as an ISD Sequence instance.</p>
-<p>All ISD related vocabulary is defined in the TTML ISD Namespace, defined here as <code>http://www.w3.org/ns/ttml#isd</code>,
-where the recommended prefix is <code>isd</code>.</p>
-<p>A TTML <loc href="#terms-intermediate-synchronic-document">Intermediate Synchronic Document</loc>, in short, an <emph>ISD</emph> or <emph>ISD instance</emph>,
-represents a discrete, temporally non-overlapping interval, an <emph>ISD interval</emph>,
-of a source TTML document where, except for non-discrete animation, all content, styling, and layout information remains static within that interval.
-In particular, the timing hierarchy of a TTML document is flattened and then sub-divided into temporally non-overlapping intervals, where each such
-interval defines a static view of the source TTML document within that interval, and where that static view is represented as an ISD instance.
-A concrete, standalone instance of a TTML
-<loc href="#terms-intermediate-synchronic-document">Intermediate Synchronic Document</loc> must specify an
-<loc href="#isd-vocabulary-isd"><el>isd:isd</el></loc> element as its root document element. When an instance of a
-<loc href="#terms-intermediate-synchronic-document">Intermediate Synchronic Document</loc> is included in a
-<loc href="#terms-intermediate-synchronic-document-sequence">Intermediate Synchronic Document Sequence</loc> instance, then the ISD instance is represented
-by an <loc href="#isd-vocabulary-isd"><el>isd:isd</el></loc> child element of the root 
-<loc href="#isd-vocabulary-sequence"><el>isd:sequence</el></loc> element.</p>
-<note role="elaboration">
-<p>An ISD instance may contain one or more animate elements that denote continuous animation within the associated interval. Continuously animated styles are sub-divided across
-ISD interval boundaries such that their step-wise concatenation expresses an equivalent continuous animation over any intersecting ISD interval(s).</p>
-</note>
-<p>A TTML <loc href="#terms-intermediate-synchronic-document-sequence">Intermediate Synchronic Document Sequence</loc> represents a collection
-of temporally non-overlapping <loc href="#terms-intermediate-synchronic-document">Intermediate Synchronic Document</loc> instances ordered according
-to their begin times. A concrete instance of a TTML
-<loc href="#terms-intermediate-synchronic-document-sequence">Intermediate Synchronic Document Sequence</loc> must specify an
-<loc href="#isd-vocabulary-sequence"><el>isd:sequence</el></loc> element as its root document element.</p>
-<div2 id="isd-vocabulary">
-<head>ISD Vocabulary</head>
-<div3 id="isd-vocabulary-sequence">
-<head>isd:sequence</head>
-<p>The <el>isd:sequence</el> element serves as the root document element of an <loc href="#terms-intermediate-synchronic-document-sequence">Intermediate
-Synchronic Document Sequence</loc>  document.</p>
-<p>The <el>isd:sequence</el> element accepts as its children zero or more elements in the
-<loc href="#element-vocab-group-metadata"><code>Metadata.class</code></loc> element group,
-followed by zero or one <loc href="#profile-vocabulary-profile"><el>ttp:profile</el></loc> element,
-followed by zero or more <loc href="#isd-vocabulary-isd"><el>isd:isd</el></loc> elements.</p>
-<p>Child <el>isd:isd</el> elements must be ordered in accordance to the media time equivalent of their
-begin time; furthermore, the temporal intervals of any two child <loc href="#isd-vocabulary-isd"><el>isd:isd</el></loc> elements must not overlap (in time).</p>
-<table id="elt-syntax-isd-sequence" role="syntax">
-<caption>XML Representation &ndash; Element Information Item: isd:sequence</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;isd:sequence
-  size = <loc href="http://www.w3.org/TR/xmlschema-2/#nonNegativeInteger">xsd:nonNegativeInteger</loc>
-  version = <loc href="http://www.w3.org/TR/xmlschema-2/#positiveInteger">xsd:positiveInteger</loc>
-  <loc href="#content-attribute-xml-lang"><phrase role="reqattr">xml:lang</phrase></loc> = <loc href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</loc>
-  {<emph>any attribute in the <loc href="#isd-parameter-attribute-set">ISD Parameter Attribute Set</loc></emph>}&gt;
-  {<emph>any attribute not in default or any TT namespace</emph>}&gt;
-  <emph>Content:</emph> <loc href="#element-vocab-group-metadata">Metadata.class</loc>*, <loc href="#profile-vocabulary-profile">ttp:profile</loc>?, <loc href="#isd-vocabulary-isd">isd:isd</loc>*
-&lt;/isd:sequence&gt;
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p>If the <att>size</att> attribute is specified, then it must be a non-negative integer corresponding to the number of
-<loc href="#isd-vocabulary-isd"><el>isd:isd</el></loc> child elements.
-If not specified, then the size must be considered to be <emph>indefinite</emph>, unless and until the
-<loc href="#isd-vocabulary-sequence"><el>isd:sequence</el></loc> element is terminated, in which case the size
-may be determined by inspection.</p>
-<note role="elaboration">
-<p>The <att>size</att> attribute would normally be omitted in the case of real time captioning.</p>
-</note>
-<p>If the <att>version</att> attribute is specified, then it must be a positive integer corresponding to the version of this
-<loc href="#terms-intermediate-synchronic-document-syntax">Intermediate Synchronic Document Syntax</loc> specification used in authoring
-the ISD sequence document. If specified, the numeric value must be greater than or equal to two (2). If not specified, then the version must be
-consider to be equal to two (2). The version associated with this
-<loc href="#terms-intermediate-synchronic-document-sequence-syntax">Intermediate Synchronic Document Sequence Syntax</loc> specification is two (2).</p>
-<note role="elaboration">
-<p>The ISD abstraction referred to or implied by <bibref ref="ttml1"/> &sect;9.3.2 was not concretely defined by that specification. Here we reserve version one (1)
-for informal discussion of that earlier abstraction and its various (non-standardized) realizations.</p>
-</note>
-<p>An <loc href="#content-attribute-xml-lang"><att>xml:lang</att></loc> attribute must be specified on the
-<loc href="#isd-vocabulary-sequence"><el>isd:sequence</el></loc> element.
-If its value is empty, it signifies that there is no default language that applies
-to the content within the <loc href="#terms-intermediate-synchronic-document-sequence">Intermediate Synchronic Document Sequence</loc>. Otherwise,
-the specified value denotes the default language that applies to each constituent
-<loc href="#terms-intermediate-synchronic-document">Intermediate Synchronic Document</loc>.</p>
-<p>One or more parameter properties may be specified from the restricted parameter attribute set enumerated in <specref ref="isd-parameter-attribute-set"/>.
-If specified, then they apply globally to each constituent <loc href="#terms-intermediate-synchronic-document">Intermediate Synchronic Document</loc>.</p>
-<p>If a child <loc href="#profile-vocabulary-profile"><el>ttp:profile</el></loc> element is present,
-then that <loc href="#profile-vocabulary-profile"><el>ttp:profile</el></loc> element must satisfy the following constraints:</p>
-<ulist>
-<item><p>no <att>combine</att> attribute is specified;</p></item>
-<item><p>no <att>designator</att> attribute is specified;</p></item>
-<item><p>no <att>type</att> attribute is specified;</p></item>
-<item><p>no <att>use</att> attribute is specified;</p></item>
-<item><p>no descendant element is a <el>ttp:profile</el> element;</p></item>
-<item><p>no descendant <el>ttp:feature</el> element specifies a <att>value</att> attribute with the value <code>prohibited</code>;</p></item>
-<item><p>no descendant <el>ttp:extension</el> element specifies a <att>value</att> attribute with the value <code>prohibited</code>.</p></item>
-</ulist>
-<p>Furthermore, such a child <loc href="#profile-vocabulary-profile"><el>ttp:profile</el></loc> element must specify a profile that is equivalent to the combined
-<loc href="#terms-processor-profile">processor profile</loc> of the source TTML document having fetched all externally referenced profile documents.</p>
-<note role="elaboration">
-<p>The intent of permitting a single <loc href="#profile-vocabulary-profile"><el>ttp:profile</el></loc> to be specified in an
-<loc href="#isd-vocabulary-sequence"><el>isd:sequence</el></loc> is to provide a simplified mechanism to declare
-processor profile requirements that must be met in order to process the document (in the absence of an end-user override).</p>
-</note>
-</div3>
-<div3 id="isd-vocabulary-isd">
-<head>isd:isd</head>
-<p>The <el>isd:isd</el> element serves either as (1) the root document element of a standalone <loc href="#terms-intermediate-synchronic-document">Intermediate
-Synchronic Document</loc> or (2) as a child of an <loc href="#isd-vocabulary-sequence"><el>isd:sequence</el></loc> element of a
-<loc href="#terms-intermediate-synchronic-document-sequence">Intermediate Synchronic Document Sequence</loc> document.</p>
-<p>The <el>isd:isd</el> element accepts as its children zero or more elements in the
-<loc href="#element-vocab-group-metadata"><code>Metadata.class</code></loc> element group,
-followed by zero or one <loc href="#profile-vocabulary-profile"><el>ttp:profile</el></loc> element,
-followed by zero or more <loc href="#isd-vocabulary-css"><el>isd:css</el></loc> elements,
-followed by zero or more <loc href="#isd-vocabulary-region"><el>isd:region</el></loc> elements.</p>
-<table id="elt-syntax-isd" role="syntax">
-<caption>XML Representation &ndash; Element Information Item: isd:isd</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;isd:isd
-  <loc href="#timing-attribute-begin"><phrase role="reqattr">begin</phrase></loc> = <loc href="#timing-value-timeExpression">&lt;timeExpression&gt;</loc>
-  <loc href="#timing-attribute-end"><phrase role="reqattr">end</phrase></loc> = <loc href="#timing-value-timeExpression">&lt;timeExpression&gt;</loc>
-  version = <loc href="http://www.w3.org/TR/xmlschema-2/#positiveInteger">xsd:positiveInteger</loc>
-  <loc href="#content-attribute-xml-lang">xml:lang</loc> = <loc href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</loc>
-  {<emph>any attribute in the <loc href="#isd-parameter-attribute-set">ISD Parameter Attribute Set</loc></emph>}&gt;
-  {<emph>any attribute not in default or any TT namespace</emph>}&gt;
-  <emph>Content:</emph> <loc href="#element-vocab-group-metadata">Metadata.class</loc>*, <loc href="#profile-vocabulary-profile">ttp:profile</loc>?, <loc href="#isd-vocabulary-css">isd:css</loc>*, <loc href="#isd-vocabulary-region">isd:region</loc>*
-&lt;/isd:isd&gt;
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p>A <att>begin</att> attribute must be specified, the value of which must take the <emph>offset-time</emph> form of
-a <loc href="#timing-value-timeExpression">&lt;timeExpression&gt;</loc>, and, further, is restricted to use a metric of
-<code>s</code> (seconds),
-<code>f</code> (frames),
-<code>t</code> (ticks), or may omit the metric, in which case <code>s</code> seconds is implied. This
-begin time is expressed as an offset from the begin time of the <loc href="#terms-root-temporal-extent">root temporal extent</loc>
-of the source TTML document from which this <loc href="#isd-vocabulary-isd"><el>isd:isd</el></loc> element was derived.</p>
-<p>An <att>end</att> attribute must be similarlly specified, where the same constraints apply.
-This end time is expressed as an offset from the begin time of the <loc href="#terms-root-temporal-extent">root temporal extent</loc>
-of the source TTML document from which this <loc href="#isd-vocabulary-isd"><el>isd:isd</el></loc> element was derived.</p>
-<note role="elaboration">
-<p>Expressed in the terminology of <bibref ref="smil3"/>, the values of these <att>begin</att> and <att>end</att> attributes
-correspond to the resolved begin and end times of the <emph>active duration</emph> with respect to the <emph>document begin</emph>.</p>
-</note>
-<p>An <loc href="#content-attribute-xml-lang"><att>xml:lang</att></loc> attribute must be specified on the
-<loc href="#isd-vocabulary-isd"><el>isd:isd</el></loc> element if it is a standalone <loc href="#terms-intermediate-synchronic-document">Intermediate
-Synchronic Document</loc> document; otherwise, it may be specified, and should be specified if the default language of the 
-<loc href="#isd-vocabulary-sequence"><el>isd:isd</el></loc> element differs from the default language of its
-parent <loc href="#isd-vocabulary-sequence"><el>isd:sequence</el></loc> element.
-If its value is empty, it signifies that there is no default language that applies
-to the content within the <loc href="#terms-intermediate-synchronic-document">Intermediate Synchronic Document</loc>. Otherwise,
-the specified value denotes the default language that applies.</p>
-<p>The <att>version</att> attribute follows the syntax and semantics of the same named attribute on the
-<loc href="#isd-vocabulary-sequence"><el>isd:sequence</el></loc> element type. The <att>version</att>
-attribute must not be specified on an <loc href="#isd-vocabulary-isd">isd:isd</loc> element that is not
-a root document element, i.e., is a child element of an <loc href="#isd-vocabulary-sequence">isd:sequence</loc> element.</p>
-<p>A child <loc href="#profile-vocabulary-profile"><el>ttp:profile</el></loc> element may be present if the
-<loc href="#isd-vocabulary-isd"><el>isd:isd</el></loc> element is a standalone <loc href="#terms-intermediate-synchronic-document">Intermediate
-Synchronic Document</loc> document, in which case the same constraints and semantics apply as specified in <specref ref="isd-vocabulary-sequence"/>;
-otherwise, if not a standalone document, a child <loc href="#profile-vocabulary-profile"><el>ttp:profile</el></loc> element must not be present.</p>
-</div3>
-<div3 id="isd-vocabulary-css">
-<head>isd:css</head>
-<p>The <el>isd:css</el> element is used to represent a unique computed style set of some collection of elements
-that share the same set of computed styles. In particular, for each
-element <emph>E</emph> in the source TTML document which is selected and copied into a
-<loc href="#isd-vocabulary-region"><el>isd:region</el></loc> element of a given
-<loc href="#terms-intermediate-synchronic-document">Intermediate Synchronic Document</loc>, the computed style
-set of <emph>E</emph>, <emph>CSS(E)</emph>, is determined, and, if that <emph>CSS(E)</emph> is not already specified
-by an existing <el>isd:css</el> element, then it is assigned a unique identifier and instantiated as a new
-<el>isd:css</el> element.</p>
-<p>The <el>isd:css</el> element accepts as its children zero or more elements in the
-<loc href="#element-vocab-group-metadata"><code>Metadata.class</code></loc> element group.</p>
-<table id="elt-syntax-isd-style" role="syntax">
-<caption>XML Representation &ndash; Element Information Item: isd:css</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;isd:css
-  <loc href="#content-attribute-xml-id"><phrase role="reqattr">xml:id</phrase></loc> = ID
-  {<emph>any attribute in TT Style namespace</emph>}
-  {<emph>any attribute not in default or any TT namespace</emph>}&gt;
-  <emph>Content:</emph> <loc href="#element-vocab-group-metadata">Metadata.class</loc>*
-&lt;/isd:css&gt;
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p>For each arbitrary pair of <el>isd:css</el> child elements of an
-<loc href="#isd-vocabulary-isd"><el>isd:isd</el></loc> element,
-<emph>S1</emph> and <emph>S2</emph>, the set of specified styles of <emph>S1</emph> must
-not be the same as the set of specified styles of <emph>S2</emph>. For the purpose of comparing two
-sets of specified styles, the styles must be placed into a canonical order and then compared item
-by item for value equality, where the canonical order is in accordance to the qualified attribute name
-order, where each qualified name consists of a tuple <code>&lt;namespace URL, local name&gt;</code>,
-and such tuples are compared component-wise by case-sensitive lexical string order.</p>
-</div3>
-<div3 id="isd-vocabulary-region">
-<head>isd:region</head>
-<p>The <el>isd:region</el> element is used to represent a layout and presentation region
-and the content selected into that region, where that content takes the form of a
-<loc href="#document-structure-vocabulary-body">body</loc> element and its descendant TTML content elements.</p>
-<p>The <el>isd:region</el> element accepts as its children zero or more elements in the
-<loc href="#element-vocab-group-metadata"><code>Metadata.class</code></loc> element group,
-followed by zero or more <loc href="#animation-vocabulary-animate"><el>animate</el></loc> elements,
-followed by exactly one <loc href="#document-structure-vocabulary-body"><el>body</el></loc> element.</p>
-<table id="elt-syntax-isd-region" role="syntax">
-<caption>XML Representation &ndash; Element Information Item: isd:region</caption>
-<tbody>
-<tr>
-<td>
-<eg xml:space="preserve">
-&lt;isd:region
-  <loc href="#style-attribute-style">style</loc> = IDREF
-  <loc href="#metadata-attribute-role">ttm:role</loc> = <loc href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</loc>
-  <loc href="#content-attribute-xml-id"><phrase role="reqattr">xml:id</phrase></loc> = ID
-  {<emph>any attribute not in default or any TT namespace</emph>}&gt;
-  <emph>Content:</emph> <loc href="#element-vocab-group-metadata">Metadata.class</loc>*, <loc href="#animation-vocabulary-animate">animate</loc>*, <loc href="#document-structure-vocabulary-body">body</loc>
-&lt;/isd:region&gt;
-</eg>
-</td>
-</tr>
-</tbody>
-</table>
-<p>If the computed style set of the region represented by the <el>isd:region</el> element is not the
-set of initial style values that apply to <loc href="#layout-vocabulary-region"><el>region</el></loc>, then a
-<att>style</att> attribute must be specified which references an <loc href="#isd-vocabulary-css"><el>isd:css</el></loc> element that specifies the
-region's computed style set.</p>
-<p>The following constraints apply to the <loc href="#document-structure-vocabulary-body"><el>body</el></loc> element
-and its descendant elements:</p>
-<ulist>
-<item><p>no <att>animate</att> attribute is specified;</p></item>
-<item><p>no <att>begin</att> attribute is specified;</p></item>
-<item><p>no <att>dur</att> attribute is specified;</p></item>
-<item><p>no <att>end</att> attribute is specified;</p></item>
-<item><p>no <att>region</att> attribute is specified;</p></item>
-<item><p>no <att>timeContainer</att> attribute is specified;</p></item>
-<item><p>no attribute in the TT Style namespace is specified;</p></item>
-<item><p>no <loc href="#animation-vocabulary-set">set</loc> element is present;</p></item>
-<item><p>no significant text node, i.e., text node in a #PCDATA context, is not contained in a 
-<loc href="#content-vocabulary-span"><el>span</el></loc> element that contains no other child.</p></item>
-</ulist>
-<p>In addition, for the <loc href="#document-structure-vocabulary-body"><el>body</el></loc> element <emph>B</emph> and
-each of its descendant content elements <emph>C</emph>, if the computed style set of <emph>B</emph> or each <emph>C</emph> is
-not equal to the computed style set of its parent element, then that element, <emph>B</emph> or <emph>C</emph>, must specify a <att>style</att>
-attribute that references an <loc href="#isd-vocabulary-css"><el>isd:css</el></loc> element that specifies the
-element's computed style set.</p>
-</div3>
-</div2>
-<div2 id="isd-parameter-attribute-set">
-<head>ISD Parameter Attribute Set</head>
-<p>The following subset of the defined <loc href="#attribute-vocab-group-parameters">Parameter Attributes</loc>
-are available for use with an
-<loc href="#isd-vocabulary-sequence"><el>isd:sequence</el></loc> or
-<loc href="#isd-vocabulary-isd"><el>isd:isd</el></loc> element as described above:</p>
-<ulist>
-<item><p><loc href="#parameter-attribute-cellResolution">ttp:cellResolution</loc></p></item>
-<item><p><loc href="#parameter-attribute-frameRate">ttp:frameRate</loc></p></item>
-<item><p><loc href="#parameter-attribute-frameRateMultiplier">ttp:frameRateMultipler</loc></p></item>
-<item><p><loc href="#parameter-attribute-mediaOffset">ttp:mediaOffset</loc></p></item>
-<item><p><loc href="#parameter-attribute-pixelAspectRatio">ttp:pixelAspectRatio</loc></p></item>
-<item><p><loc href="#parameter-attribute-subFrameRate">ttp:subFrameRate</loc></p></item>
-<item><p><loc href="#parameter-attribute-tickRate">ttp:tickRate</loc></p></item>
-</ulist>
-</div2>
-<div2 id="isd-interchange">
-<head>ISD Interchange</head>
-<p>A concrete document instance that employs the <loc href="#isd">Intermediate Synchronic Document Syntax</loc> must be
-encoded as a well-formed <bibref ref="xml10"/> document using the UTF-8 character encoding. Furthermore, such a document must specify
-an <loc href="#isd-vocabulary-sequence"><el>isd:sequence</el></loc> element or
-an <loc href="#isd-vocabulary-isd"><el>isd:isd</el></loc> element as the root document element.</p>
-<p>When a resource consisting of a concrete ISD Sequence or ISD instance is interchanged and a media type is used to identify the content type
-of that resource, then the media type <code>application/ttml+xml</code> should be used, about which see <bibref ref="ttml1"/> Appendix C.
-If this media type is used, the optional <code>profile</code> parameter must not be specified, or, if specified, must be ignored by a processor.</p>
-</div2>
-<div2 id="isd-examples">
-<head>ISD Examples</head>
-<p><emph>This sub-section is non-normative.</emph></p>
-<ednote>
-<name>Add ISD Examples</name>
-<date>2014-09-22</date>
-<edtext>Add worked out examples of ISD Sequence and ISD document instances.</edtext>
-</ednote>
-</div2>
+<issue id="issue-352">
+<head>Restore Media Type Registration</head>
+<source><loc href="http://www.w3.org/AudioVideo/TT/tracker/issues/352">http://www.w3.org/AudioVideo/TT/tracker/issues/352</loc></source>
+<p>Restore and update media type registration for IANA update.</p>
+</issue>
+<p></p>
+<issue id="issue-351">
+<head>Processor Profiles Parameter</head>
+<source><loc href="http://www.w3.org/AudioVideo/TT/tracker/issues/351">http://www.w3.org/AudioVideo/TT/tracker/issues/351</loc></source>
+<p>Add definition of <code>processorProfiles</code> media type parameter.</p>
+</issue>
 </div1>
 <div1 id="features">
 <head>Features</head>
@@ -18580,7 +18426,7 @@
 whether the feature must be implemented, i.e., is mandatory (M), or may be implemented, i.e.,
 is optional (O), for transformation and <loc href="#terms-presentation-processor">presentation processor</loc>s.</p>
 <table id="feature-support-table" role="common">
-<caption>Table D-1 &ndash; Feature Support</caption>
+<caption>Table E-1 &ndash; Feature Support</caption>
 <col width="60%"/>
 <col width="20%"/>
 <col width="20%"/>
@@ -19186,7 +19032,7 @@
 <specref ref="profile-ttml2-transformation"/>.
 </p>
 <table id="feature-transformation-mandatory-table" role="common">
-<caption>Table D-2 &ndash; Mandatory Features - Transformation</caption>
+<caption>Table E-2 &ndash; Mandatory Features - Transformation</caption>
 <col width="60%"/>
 <col width="40%"/>
 <tbody>
@@ -19250,7 +19096,7 @@
 <specref ref="profile-ttml2-presentation"/>.
 </p>
 <table id="feature-presentation-mandatory-table" role="common">
-<caption>Table D-3 &ndash; Mandatory Features - Presentation</caption>
+<caption>Table E-3 &ndash; Mandatory Features - Presentation</caption>
 <col width="60%"/>
 <col width="40%"/>
 <tbody>
@@ -19393,6 +19239,684 @@
 <eg xml:space="preserve">&profile-ttml2-transformation;</eg>
 </div2>
 </div1>
+<div1 id="time-expression-semantics">
+<head>Time Expression Semantics</head>
+<p><emph>This appendix is normative.</emph></p>
+<p>This appendix specifies the semantics for interpreting time expressions in <loc href="#terms-document-instance">document instances</loc>.</p>
+<note role="clarification">
+<p>The phrase <emph>local real time</emph> as used below is intended to model a virtual real time clock in the document processing context, where
+<emph>local</emph> means in the immediate proximity of the implementation of this processing context. The intent
+of defining relationships with this virtual clock is to establish a locally valid physical realization of time for didactic purposes.</p>
+</note>
+<note role="clarification">
+<p>The phrase <emph>play rate</emph> as used below is intended to model a (possibly variable) parameter in the document processing context wherein
+the rate of playback (or interpretation) of time may artificially dilated or narrowed, for example, when slowing down or speeding up the rate of
+playback of a <loc href="#terms-related-media-object">related media object</loc>. Without loss of generality, the following discussion assumes a fixed play(back) rate. In the case of
+variable play rates, appropriate adjustments may need to be made to the resulting computations.</p>
+</note>
+<div2 id="time-expression-semantics-clock">
+<head>Clock Time Base</head>
+<p>When operating with the <code>clock</code> time base, the following semantics apply for interpreting time expressions,
+as defined by <loc href="#timing-value-timeExpression">&lt;timeExpression&gt;</loc>, and their relationship to media time and local real time.</p>
+<p>The clock time base <phrase role="strong"><code>C</code></phrase> is related to local real time <phrase role="strong"><code>R</code></phrase>
+expressed in an arbitrary (implementation defined) epoch <phrase role="strong"><code>E</code></phrase>
+as follows:</p>
+<table id="clock-time-and-real-time" role="semantics">
+<caption>TTML Semantics &ndash; Clock Time and Real Time Relationship</caption>
+<tbody>
+<tr>
+<td>
+<slist>
+<sitem/>
+<sitem>
+<code>R = C + epochOffset + discontinuityOffset</code>
+</sitem>
+<sitem/>
+<sitem>
+where <code>C &isin; &real;</code>, <code>0 &le; C &lt; &infin;</code>, <code>C</code> in seconds since the most immediately prior midnight of the reference clock base;
+</sitem>
+<sitem/>
+<sitem>
+<code>epochOffset &isin; &real;</code>, <code>0 &le; epochOffset &lt; &infin;</code>, <code>epochOffset</code> in seconds, with 0 being the beginning
+of epoch <code>E</code>, and where the value of <code>epochOffset</code> is determined from the computed value of the <code>ttp:clockMode</code> parameter
+as follows:
+</sitem>
+<sitem/>
+<sitem>
+(1) if <code>local</code>, then the difference between the local real time at the most immediately prior local midnight and the local real time
+at the beginning of epoch <code>E</code>, expressed in seconds;
+</sitem>
+<sitem/>
+<sitem>
+(2) if <code>gps</code>, then the difference between the GPS time at the most immediately prior GPS midnight
+and the GPS time at the beginning of epoch <code>E</code>, expressed in seconds;
+</sitem>
+<sitem/>
+<sitem>
+(3) if <code>utc</code>, then the difference between the UTC time at the most immediately prior UTC midnight
+and the UTC time at the beginning of epoch <code>E</code>, expressed in seconds;
+</sitem>
+<sitem/>
+<sitem>
+<code>discontinuityOffset &isin; &real;</code>, <code>&minus;&infin; &lt; discontinuityOffset &lt; &infin;</code>, <code>discontinuityOffset</code> in seconds,
+and where the value of <code>discontinuityOffset</code> is equal to the sum of leap seconds (and fractions thereof) that have been added (or subtracted) since the
+most immediately prior midnight in the reference clock base;
+</sitem>
+<sitem/>
+<sitem>
+and <code>epochOffset</code> and <code>discontinuityOffset</code> are determined once and only once prior to the beginning of the <loc href="#terms-root-temporal-extent">root temporal extent</loc> such that
+during the period between value determination and the beginning of the <loc href="#terms-root-temporal-extent">root temporal extent</loc> there occurs no local midnight or reference clock base discontinuity.
+</sitem>
+<sitem/>
+</slist>
+</td>
+</tr>
+</tbody>
+</table>
+<p>Time value expressions, as denoted by a <loc href="#timing-value-timeExpression">&lt;timeExpression&gt;</loc>, are related to
+clock time <phrase role="strong"><code>C</code></phrase> as follows:</p>
+<table id="time-expressions-and-clock-time" role="semantics">
+<caption>TTML Semantics &ndash; Time Expressions and Clock Time Relationship</caption>
+<tbody>
+<tr>
+<td>
+<slist>
+<sitem/>
+<sitem>
+If a time expression uses the <emph>clock-time</emph> form or an <emph>offset-time</emph> form that doesn't use the ticks (<code>t</code>) metric, then:
+</sitem>
+<sitem/>
+<sitem>
+<code>C = 3600 * hours + 60 * minutes + seconds</code>
+</sitem>
+<sitem/>
+<sitem>
+where
+<code>hours</code>,
+<code>minutes</code>,
+<code>seconds</code> components are extracted from time expression if present, or zero if not present.
+</sitem>
+<sitem/>
+<sitem>
+Otherwise, if a time expression uses an <emph>offset-time</emph> form that uses the ticks (<code>t</code>) metric, then:
+</sitem>
+<sitem/>
+<sitem>
+<code>C = ticks / tickRate</code>
+</sitem>
+<sitem/>
+</slist>
+</td>
+</tr>
+</tbody>
+</table>
+<note role="clarification">
+<p>The <emph>frames</emph> and <emph>sub-frames</emph> terms and the frames (<code>f</code>) metric of time expressions do not apply when using
+the <code>clock</code> time base.</p>
+</note>
+<p>The clock time base <phrase role="strong"><code>C</code></phrase> is independent of media time <phrase role="strong"><code>M</code></phrase>:</p>
+<table id="clock-time-and-media-time" role="semantics">
+<caption>TTML Semantics &ndash; Clock Time and Media Time Relationship</caption>
+<tbody>
+<tr>
+<td>
+<slist>
+<sitem/>
+<sitem>
+<code>M &not;&prop; C</code>
+</sitem>
+<sitem/>
+</slist>
+</td>
+</tr>
+</tbody>
+</table>
+<note role="elaboration">
+<p>That is to say, timing is disconnected from (not necessarily proportional to) media time when
+the <code>clock</code> time base is used. For example, if the media play rate is zero (0), media playback is suspended; however, timing coordinates
+will continue to advance according to the natural progression of clock time in direct proportion to the reference clock base. Furthermore, if the media play rate changes
+during playback, presentation timing is not affected.
+</p>
+</note>
+</div2>
+<div2 id="time-expression-semantics-media">
+<head>Media Time Base</head>
+<p>When operating with the <code>media</code> time base, the following semantics apply for interpreting time expressions,
+as defined by <loc href="#timing-value-timeExpression">&lt;timeExpression&gt;</loc>, and their relationship to media time and local real time.</p>
+<issue id="issue-306">
+<head>Fractional Time Expressions</head>
+<source><loc href="http://www.w3.org/AudioVideo/TT/tracker/issues/306">http://www.w3.org/AudioVideo/TT/tracker/issues/306</loc></source>
+<p>Augment syntax to cover fractional time expressions.</p>
+</issue>
+<p>The media time base <phrase role="strong"><code>M</code></phrase> is related to local real time <phrase role="strong"><code>R</code></phrase>
+expressed in an arbitrary (implementation defined) epoch <phrase role="strong"><code>E</code></phrase> as follows:</p>
+<table id="media-time-and-real-time" role="semantics">
+<caption>TTML Semantics &ndash; Media Time and Real Time Relationship</caption>
+<tbody>
+<tr>
+<td>
+<slist>
+<sitem/>
+<sitem>
+<code>R = playRate * M + epochOffset</code>
+</sitem>
+<sitem/>
+<sitem>
+where <code>M &isin; &real;</code>, <code>0 &le; M &lt; &infin;</code>, <code>M</code> in seconds, with 0 corresponding to the beginning of the <loc href="#terms-root-temporal-extent">root temporal extent</loc>;
+</sitem>
+<sitem/>
+<sitem>
+<code>playRate &isin; &real;</code>, <code>&minus;&infin; &lt; playRate &lt; &infin;</code>, <code>playRate</code> is unit-less, and where the value of
+<code>playRate</code> is determined by the document processing context;
+</sitem>
+<sitem/>
+<sitem>
+and <code>epochOffset &isin; &real;</code>, <code>0 &le; epochOffset &lt; &infin;</code>, <code>epochOffset</code> in seconds, with 0 corresponding to the beginning of
+an epoch <code>E</code>, and where the value of <code>epochOffset</code> is the difference between the local real time at the beginning of the
+<loc href="#terms-root-temporal-extent">root temporal extent</loc> and the local real time at the the beginning of epoch <code>E</code>, expressed in seconds.
+</sitem>
+</slist>
+</td>
+</tr>
+</tbody>
+</table>
+<p>Time value expressions, as denoted by a <loc href="#timing-value-timeExpression">&lt;timeExpression&gt;</loc>, are related to
+media time <phrase role="strong"><code>M</code></phrase> in accordance to the
+<code>ttp:frameRate</code>, <code>ttp:subFrameRate</code>, and <code>ttp:frameRateMultipler</code> parameters as follows:</p>
+<table id="time-expressions-and-media-time" role="semantics">
+<caption>TTML Semantics &ndash; Time Expressions and Media Time Relationship</caption>
+<tbody>
+<tr>
+<td>
+<slist>
+<sitem/>
+<sitem>
+If a time expression uses a <emph>clock-time</emph> form or an <emph>offset-time</emph> form that doesn't use the ticks (<code>t</code>) metric, then:
+</sitem>
+<sitem/>
+<sitem>
+<code>
+M = referenceBegin + 3600 * hours + 60 * minutes + seconds + ((frames + (subFrames / subFrameRate)) / effectiveFrameRate)
+</code>
+</sitem>
+<sitem/>
+<sitem>
+where <code>referenceBegin</code> is determined according to whether the nearest ancestor time container employs
+parallel (<code>par</code>) or sequential (<code>seq</code>) semantics: if parallel or if sequential and no prior sibling
+timed element exists, then <code>referenceBegin</code>
+is the media time that corresponds to the beginning of the nearest ancestor time container or
+zero (0) if this time container is the <loc href="#terms-root-temporal-extent">root temporal extent</loc>; otherwise, if sequential and a prior sibling
+timed element exists, then <code>referenceBegin</code> is the media time that corresponds to the active end of the
+immediate prior sibling timed element;
+</sitem>
+<sitem/>
+<sitem>
+the <code>hours</code>, <code>minutes</code>, <code>seconds</code>, <code>frames</code>, <code>subFrames</code> components
+are extracted from time expression if present, or zero if not present;
+</sitem>
+<sitem/>
+<sitem>
+<code>subFrameRate</code> is the computed value of the <att>ttp:subFrameRate</att> parameter;
+</sitem>
+<sitem/>
+<sitem>
+and <code>effectiveFrameRate</code> (in frames per second) is <code>frameRate * frameRateMultipler</code> where
+<code>frameRate</code> is the computed value of the <att>ttp:frameRate</att> parameter and
+<code>frameRateMultipler</code> is the computed value of the <att>ttp:frameRateMultiplier</att> parameter.
+</sitem>
+<sitem/>
+<sitem>
+Otherwise, if a time expression uses an <emph>offset-time</emph> form that uses the ticks (<code>t</code>) metric, then:
+</sitem>
+<sitem/>
+<sitem>
+<code>
+M = referenceBegin + ticks / tickRate
+</code>
+</sitem>
+<sitem/>
+<sitem>
+where <code>referenceBegin</code> is as described above;
+</sitem>
+<sitem/>
+<sitem>
+the <code>ticks</code> component is extracted from time expression;
+</sitem>
+<sitem/>
+<sitem>
+and <code>tickRate</code> is the computed value of the <att>ttp:tickRate</att> parameter;
+</sitem>
+<sitem/>
+</slist>
+</td>
+</tr>
+</tbody>
+</table>
+<note role="elaboration">
+<p>If the computed <code>frameRateMultipler</code> ratio is not integral, then <code>effectiveFrameRate</code> will be a non-integral rational.</p>
+</note>
+<note role="clarification">
+<p>The begin time of the <loc href="#terms-root-temporal-extent">root temporal extent</loc> is related to the begin time of a
+<loc href="#terms-related-media-object">related media object</loc> in accordance with the computed value of the
+<loc href="#parameter-attribute-mediaOffset"><att>ttp:mediaOffset</att></loc> parameter property.</p>
+</note>
+</div2>
+<div2 id="time-expression-semantics-smpte">
+<head>SMPTE Time Base</head>
+<p>When operating with the <code>smpte</code> time base, the following semantics apply for interpreting time expressions,
+as defined by <loc href="#timing-value-timeExpression">&lt;timeExpression&gt;</loc>, and their relationship to media time and local real time.</p>
+<issue id="issue-322">
+<head>Incorrect Expression for NTSC Drop Mode</head>
+<source><loc href="http://www.w3.org/AudioVideo/TT/tracker/issues/322">http://www.w3.org/AudioVideo/TT/tracker/issues/322</loc></source>
+<p>Correct formula for NTSC drop mode calculation.</p>
+</issue>
+<p>If the computed value of the <att>ttp:markerMode</att> parameter is <code>discontinuous</code>, then there is no direct relationship between
+time expressions and media time <phrase role="strong"><code>M</code></phrase> or local real time <phrase role="strong"><code>R</code></phrase>. In
+this case, time expressions refer to synchronization events (markers) emitted by the <loc href="#terms-document-processing-context">document processing context</loc>
+when <loc href="#terms-smpte-time-code">smpte time codes</loc>
+are encountered in the <loc href="#terms-related-media-object">related media object</loc>.</p>
+<p>Otherwise, if the computed value of the <att>ttp:markerMode</att> parameter is <code>continuous</code>, then the relationships between time expressions and
+local real time and media time are as described below in terms of a <loc href="#terms-synthetic-smpte-document-syncbase">synthetic smpte document syncbase</loc>, here referred to as the
+SMPTE time base <phrase role="strong"><code>S</code></phrase>.</p>
+<table id="time-expressions-and-smpte-time" role="semantics">
+<caption>TTML Semantics &ndash; Time Expressions and SMPTE Time Relationship</caption>
+<tbody>
+<tr>
+<td>
+<slist>
+<sitem/>
+<sitem>
+<code>S = (countedFrames - droppedFrames + (subFrames / subFrameRate)) / effectiveFrameRate</code>
+</sitem>
+<sitem/>
+<sitem>where</sitem>
+<sitem/>
+<sitem>
+<code>countedFrames = (3600 * hours + 60 * minutes + seconds) * frameRate + frames</code>
+</sitem>
+<sitem/>
+<sitem>
+<code>hours</code>, <code>minutes</code>, <code>seconds</code>, <code>frames</code>, <code>subFrames</code> components
+are extracted from time expression if present, or zero if not present;
+</sitem>
+<sitem/>
+<sitem>
+<code>droppedFrames</code> is computed as follows:
+</sitem>
+<sitem/>
+<sitem>
+1. let <emph>dropMode</emph> be the computed value of the <att>ttp:dropMode</att> parameter;
+</sitem>
+<sitem/>
+<sitem>
+2. if <emph>dropMode</emph> is <code>dropNTSC</code>, let
+<code>droppedFrames = (hours * 54 + floor(minutes - minutes/10)) * 2</code>;
+</sitem>
+<sitem/>
+<sitem>
+3. otherwise, if <emph>dropMode</emph> is <code>dropPAL</code>, let
+<code>droppedFrames = (hours * 27 + floor(minutes/2 - minutes/20)) * 4</code>;
+</sitem>
+<sitem/>
+<sitem>
+4. otherwise, let
+<code>droppedFrames = 0</code>;
+</sitem>
+<sitem/>
+<sitem>
+<code>frameRate</code> is the computed value of the <att>ttp:frameRate</att> parameter;
+</sitem>
+<sitem/>
+<sitem>
+<code>subFrameRate</code> is the computed value of the <att>ttp:subFrameRate</att> parameter;
+</sitem>
+<sitem/>
+<sitem>
+and <code>effectiveFrameRate</code> (in frames per second) is <code>frameRate * frameRateMultipler</code> where
+<code>frameRate</code> is the computed value of the <att>ttp:frameRate</att> parameter and
+<code>frameRateMultipler</code> is the computed value of the <att>ttp:frameRateMultiplier</att> parameter.
+</sitem>
+<sitem/>
+<sitem>
+Notwithstanding the above, if a time expression contains a frame code that is designated as
+dropped according to <specref ref="parameter-attribute-dropMode"/>, then that time expression
+must be considered to be invalid for purposes of validation assessment.
+</sitem>
+<sitem/>
+</slist>
+</td>
+</tr>
+</tbody>
+</table>
+<p>The SMPTE time base <phrase role="strong"><code>S</code></phrase> is related to the media time base <phrase role="strong"><code>M</code></phrase> as follows:</p>
+<table id="smpte-time-and-media-time" role="semantics">
+<caption>TTML Semantics &ndash; SMPTE Time and Media Time Relationship</caption>
+<tbody>
+<tr>
+<td>
+<slist>
+<sitem/>
+<sitem>
+<code>M = referenceBegin + S</code>
+</sitem>
+<sitem/>
+<sitem>
+where <code>referenceBegin</code> is determined according to whether the nearest ancestor time container employs
+parallel (<code>par</code>) or sequential (<code>seq</code>) semantics: if parallel or if sequential and no prior sibling
+timed element exists, then <code>referenceBegin</code>
+is the SMPTE time that corresponds to the beginning of the nearest ancestor time container or
+zero (0) if this time container is the <loc href="#terms-root-temporal-extent">root temporal extent</loc>; otherwise, if sequential and a prior sibling
+timed element exists, then <code>referenceBegin</code> is the SMPTE time that corresponds to the active end of the
+immediate prior sibling timed element;
+</sitem>
+<sitem/>
+</slist>
+</td>
+</tr>
+</tbody>
+</table>
+<p>Given the derived media time base as described above, then 
+media time base <phrase role="strong"><code>M</code></phrase> is related to the local real time <phrase role="strong"><code>R</code></phrase>
+as described in <specref ref="time-expression-semantics-media"/> above.</p>
+<note role="clarification">
+<p>The begin time of the <loc href="#terms-root-temporal-extent">root temporal extent</loc> is related to the begin time of a
+<loc href="#terms-related-media-object">related media object</loc> in accordance with the computed value of the
+<loc href="#parameter-attribute-mediaOffset"><att>ttp:mediaOffset</att></loc> parameter property.</p>
+</note>
+</div2>
+</div1>
+<div1 id="isd">
+<head>Intermediate Document Syntax</head>
+<p><emph>This appendix is normative.</emph></p>
+<p>This appendix specifies the syntactic elements and structure of a
+<loc href="#terms-timed-text-intermediate-document">timed text intermediate document</loc>.
+An ISD instance may be represented as a standalone document instance or
+in a collection represented as an ISD Sequence instance.</p>
+<p>All ISD related vocabulary is defined in the TTML ISD Namespace, defined here as <code>http://www.w3.org/ns/ttml#isd</code>,
+where the recommended prefix is <code>isd</code>.</p>
+<p>A TTML <loc href="#terms-intermediate-synchronic-document">Intermediate Synchronic Document</loc>, in short, an <emph>ISD</emph> or <emph>ISD instance</emph>,
+represents a discrete, temporally non-overlapping interval, an <emph>ISD interval</emph>,
+of a source TTML document where, except for non-discrete animation, all content, styling, and layout information remains static within that interval.
+In particular, the timing hierarchy of a TTML document is flattened and then sub-divided into temporally non-overlapping intervals, where each such
+interval defines a static view of the source TTML document within that interval, and where that static view is represented as an ISD instance.
+A concrete, standalone instance of a TTML
+<loc href="#terms-intermediate-synchronic-document">Intermediate Synchronic Document</loc> must specify an
+<loc href="#isd-vocabulary-isd"><el>isd:isd</el></loc> element as its root document element. When an instance of a
+<loc href="#terms-intermediate-synchronic-document">Intermediate Synchronic Document</loc> is included in a
+<loc href="#terms-intermediate-synchronic-document-sequence">Intermediate Synchronic Document Sequence</loc> instance, then the ISD instance is represented
+by an <loc href="#isd-vocabulary-isd"><el>isd:isd</el></loc> child element of the root 
+<loc href="#isd-vocabulary-sequence"><el>isd:sequence</el></loc> element.</p>
+<note role="elaboration">
+<p>An ISD instance may contain one or more animate elements that denote continuous animation within the associated interval. Continuously animated styles are sub-divided across
+ISD interval boundaries such that their step-wise concatenation expresses an equivalent continuous animation over any intersecting ISD interval(s).</p>
+</note>
+<p>A TTML <loc href="#terms-intermediate-synchronic-document-sequence">Intermediate Synchronic Document Sequence</loc> represents a collection
+of temporally non-overlapping <loc href="#terms-intermediate-synchronic-document">Intermediate Synchronic Document</loc> instances ordered according
+to their begin times. A concrete instance of a TTML
+<loc href="#terms-intermediate-synchronic-document-sequence">Intermediate Synchronic Document Sequence</loc> must specify an
+<loc href="#isd-vocabulary-sequence"><el>isd:sequence</el></loc> element as its root document element.</p>
+<div2 id="isd-vocabulary">
+<head>ISD Vocabulary</head>
+<div3 id="isd-vocabulary-sequence">
+<head>isd:sequence</head>
+<p>The <el>isd:sequence</el> element serves as the root document element of an <loc href="#terms-intermediate-synchronic-document-sequence">Intermediate
+Synchronic Document Sequence</loc>  document.</p>
+<p>The <el>isd:sequence</el> element accepts as its children zero or more elements in the
+<loc href="#element-vocab-group-metadata"><code>Metadata.class</code></loc> element group,
+followed by zero or one <loc href="#profile-vocabulary-profile"><el>ttp:profile</el></loc> element,
+followed by zero or more <loc href="#isd-vocabulary-isd"><el>isd:isd</el></loc> elements.</p>
+<p>Child <el>isd:isd</el> elements must be ordered in accordance to the media time equivalent of their
+begin time; furthermore, the temporal intervals of any two child <loc href="#isd-vocabulary-isd"><el>isd:isd</el></loc> elements must not overlap (in time).</p>
+<table id="elt-syntax-isd-sequence" role="syntax">
+<caption>XML Representation &ndash; Element Information Item: isd:sequence</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;isd:sequence
+  size = <loc href="http://www.w3.org/TR/xmlschema-2/#nonNegativeInteger">xsd:nonNegativeInteger</loc>
+  version = <loc href="http://www.w3.org/TR/xmlschema-2/#positiveInteger">xsd:positiveInteger</loc>
+  <loc href="#content-attribute-xml-lang"><phrase role="reqattr">xml:lang</phrase></loc> = <loc href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</loc>
+  {<emph>any attribute in the <loc href="#isd-parameter-attribute-set">ISD Parameter Attribute Set</loc></emph>}&gt;
+  {<emph>any attribute not in default or any TT namespace</emph>}&gt;
+  <emph>Content:</emph> <loc href="#element-vocab-group-metadata">Metadata.class</loc>*, <loc href="#profile-vocabulary-profile">ttp:profile</loc>?, <loc href="#isd-vocabulary-isd">isd:isd</loc>*
+&lt;/isd:sequence&gt;
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p>If the <att>size</att> attribute is specified, then it must be a non-negative integer corresponding to the number of
+<loc href="#isd-vocabulary-isd"><el>isd:isd</el></loc> child elements.
+If not specified, then the size must be considered to be <emph>indefinite</emph>, unless and until the
+<loc href="#isd-vocabulary-sequence"><el>isd:sequence</el></loc> element is terminated, in which case the size
+may be determined by inspection.</p>
+<note role="elaboration">
+<p>The <att>size</att> attribute would normally be omitted in the case of real time captioning.</p>
+</note>
+<p>If the <att>version</att> attribute is specified, then it must be a positive integer corresponding to the version of this
+<loc href="#terms-intermediate-synchronic-document-syntax">Intermediate Synchronic Document Syntax</loc> specification used in authoring
+the ISD sequence document. If specified, the numeric value must be greater than or equal to two (2). If not specified, then the version must be
+consider to be equal to two (2). The version associated with this
+<loc href="#terms-intermediate-synchronic-document-sequence-syntax">Intermediate Synchronic Document Sequence Syntax</loc> specification is two (2).</p>
+<note role="elaboration">
+<p>The ISD abstraction referred to or implied by <bibref ref="ttml1"/> &sect;9.3.2 was not concretely defined by that specification. Here we reserve version one (1)
+for informal discussion of that earlier abstraction and its various (non-standardized) realizations.</p>
+</note>
+<p>An <loc href="#content-attribute-xml-lang"><att>xml:lang</att></loc> attribute must be specified on the
+<loc href="#isd-vocabulary-sequence"><el>isd:sequence</el></loc> element.
+If its value is empty, it signifies that there is no default language that applies
+to the content within the <loc href="#terms-intermediate-synchronic-document-sequence">Intermediate Synchronic Document Sequence</loc>. Otherwise,
+the specified value denotes the default language that applies to each constituent
+<loc href="#terms-intermediate-synchronic-document">Intermediate Synchronic Document</loc>.</p>
+<p>One or more parameter properties may be specified from the restricted parameter attribute set enumerated in <specref ref="isd-parameter-attribute-set"/>.
+If specified, then they apply globally to each constituent <loc href="#terms-intermediate-synchronic-document">Intermediate Synchronic Document</loc>.</p>
+<p>If a child <loc href="#profile-vocabulary-profile"><el>ttp:profile</el></loc> element is present,
+then that <loc href="#profile-vocabulary-profile"><el>ttp:profile</el></loc> element must satisfy the following constraints:</p>
+<ulist>
+<item><p>no <att>combine</att> attribute is specified;</p></item>
+<item><p>no <att>designator</att> attribute is specified;</p></item>
+<item><p>no <att>type</att> attribute is specified;</p></item>
+<item><p>no <att>use</att> attribute is specified;</p></item>
+<item><p>no descendant element is a <el>ttp:profile</el> element;</p></item>
+<item><p>no descendant <el>ttp:feature</el> element specifies a <att>value</att> attribute with the value <code>prohibited</code>;</p></item>
+<item><p>no descendant <el>ttp:extension</el> element specifies a <att>value</att> attribute with the value <code>prohibited</code>.</p></item>
+</ulist>
+<p>Furthermore, such a child <loc href="#profile-vocabulary-profile"><el>ttp:profile</el></loc> element must specify a profile that is equivalent to the combined
+<loc href="#terms-processor-profile">processor profile</loc> of the source TTML document having fetched all externally referenced profile documents.</p>
+<note role="elaboration">
+<p>The intent of permitting a single <loc href="#profile-vocabulary-profile"><el>ttp:profile</el></loc> to be specified in an
+<loc href="#isd-vocabulary-sequence"><el>isd:sequence</el></loc> is to provide a simplified mechanism to declare
+processor profile requirements that must be met in order to process the document (in the absence of an end-user override).</p>
+</note>
+</div3>
+<div3 id="isd-vocabulary-isd">
+<head>isd:isd</head>
+<p>The <el>isd:isd</el> element serves either as (1) the root document element of a standalone <loc href="#terms-intermediate-synchronic-document">Intermediate
+Synchronic Document</loc> or (2) as a child of an <loc href="#isd-vocabulary-sequence"><el>isd:sequence</el></loc> element of a
+<loc href="#terms-intermediate-synchronic-document-sequence">Intermediate Synchronic Document Sequence</loc> document.</p>
+<p>The <el>isd:isd</el> element accepts as its children zero or more elements in the
+<loc href="#element-vocab-group-metadata"><code>Metadata.class</code></loc> element group,
+followed by zero or one <loc href="#profile-vocabulary-profile"><el>ttp:profile</el></loc> element,
+followed by zero or more <loc href="#isd-vocabulary-css"><el>isd:css</el></loc> elements,
+followed by zero or more <loc href="#isd-vocabulary-region"><el>isd:region</el></loc> elements.</p>
+<table id="elt-syntax-isd" role="syntax">
+<caption>XML Representation &ndash; Element Information Item: isd:isd</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;isd:isd
+  <loc href="#timing-attribute-begin"><phrase role="reqattr">begin</phrase></loc> = <loc href="#timing-value-timeExpression">&lt;timeExpression&gt;</loc>
+  <loc href="#timing-attribute-end"><phrase role="reqattr">end</phrase></loc> = <loc href="#timing-value-timeExpression">&lt;timeExpression&gt;</loc>
+  version = <loc href="http://www.w3.org/TR/xmlschema-2/#positiveInteger">xsd:positiveInteger</loc>
+  <loc href="#content-attribute-xml-lang">xml:lang</loc> = <loc href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</loc>
+  {<emph>any attribute in the <loc href="#isd-parameter-attribute-set">ISD Parameter Attribute Set</loc></emph>}&gt;
+  {<emph>any attribute not in default or any TT namespace</emph>}&gt;
+  <emph>Content:</emph> <loc href="#element-vocab-group-metadata">Metadata.class</loc>*, <loc href="#profile-vocabulary-profile">ttp:profile</loc>?, <loc href="#isd-vocabulary-css">isd:css</loc>*, <loc href="#isd-vocabulary-region">isd:region</loc>*
+&lt;/isd:isd&gt;
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p>A <att>begin</att> attribute must be specified, the value of which must take the <emph>offset-time</emph> form of
+a <loc href="#timing-value-timeExpression">&lt;timeExpression&gt;</loc>, and, further, is restricted to use a metric of
+<code>s</code> (seconds),
+<code>f</code> (frames),
+<code>t</code> (ticks), or may omit the metric, in which case <code>s</code> seconds is implied. This
+begin time is expressed as an offset from the begin time of the <loc href="#terms-root-temporal-extent">root temporal extent</loc>
+of the source TTML document from which this <loc href="#isd-vocabulary-isd"><el>isd:isd</el></loc> element was derived.</p>
+<p>An <att>end</att> attribute must be similarlly specified, where the same constraints apply.
+This end time is expressed as an offset from the begin time of the <loc href="#terms-root-temporal-extent">root temporal extent</loc>
+of the source TTML document from which this <loc href="#isd-vocabulary-isd"><el>isd:isd</el></loc> element was derived.</p>
+<note role="elaboration">
+<p>Expressed in the terminology of <bibref ref="smil3"/>, the values of these <att>begin</att> and <att>end</att> attributes
+correspond to the resolved begin and end times of the <emph>active duration</emph> with respect to the <emph>document begin</emph>.</p>
+</note>
+<p>An <loc href="#content-attribute-xml-lang"><att>xml:lang</att></loc> attribute must be specified on the
+<loc href="#isd-vocabulary-isd"><el>isd:isd</el></loc> element if it is a standalone <loc href="#terms-intermediate-synchronic-document">Intermediate
+Synchronic Document</loc> document; otherwise, it may be specified, and should be specified if the default language of the 
+<loc href="#isd-vocabulary-sequence"><el>isd:isd</el></loc> element differs from the default language of its
+parent <loc href="#isd-vocabulary-sequence"><el>isd:sequence</el></loc> element.
+If its value is empty, it signifies that there is no default language that applies
+to the content within the <loc href="#terms-intermediate-synchronic-document">Intermediate Synchronic Document</loc>. Otherwise,
+the specified value denotes the default language that applies.</p>
+<p>The <att>version</att> attribute follows the syntax and semantics of the same named attribute on the
+<loc href="#isd-vocabulary-sequence"><el>isd:sequence</el></loc> element type. The <att>version</att>
+attribute must not be specified on an <loc href="#isd-vocabulary-isd">isd:isd</loc> element that is not
+a root document element, i.e., is a child element of an <loc href="#isd-vocabulary-sequence">isd:sequence</loc> element.</p>
+<p>A child <loc href="#profile-vocabulary-profile"><el>ttp:profile</el></loc> element may be present if the
+<loc href="#isd-vocabulary-isd"><el>isd:isd</el></loc> element is a standalone <loc href="#terms-intermediate-synchronic-document">Intermediate
+Synchronic Document</loc> document, in which case the same constraints and semantics apply as specified in <specref ref="isd-vocabulary-sequence"/>;
+otherwise, if not a standalone document, a child <loc href="#profile-vocabulary-profile"><el>ttp:profile</el></loc> element must not be present.</p>
+</div3>
+<div3 id="isd-vocabulary-css">
+<head>isd:css</head>
+<p>The <el>isd:css</el> element is used to represent a unique computed style set of some collection of elements
+that share the same set of computed styles. In particular, for each
+element <emph>E</emph> in the source TTML document which is selected and copied into a
+<loc href="#isd-vocabulary-region"><el>isd:region</el></loc> element of a given
+<loc href="#terms-intermediate-synchronic-document">Intermediate Synchronic Document</loc>, the computed style
+set of <emph>E</emph>, <emph>CSS(E)</emph>, is determined, and, if that <emph>CSS(E)</emph> is not already specified
+by an existing <el>isd:css</el> element, then it is assigned a unique identifier and instantiated as a new
+<el>isd:css</el> element.</p>
+<p>The <el>isd:css</el> element accepts as its children zero or more elements in the
+<loc href="#element-vocab-group-metadata"><code>Metadata.class</code></loc> element group.</p>
+<table id="elt-syntax-isd-style" role="syntax">
+<caption>XML Representation &ndash; Element Information Item: isd:css</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;isd:css
+  <loc href="#content-attribute-xml-id"><phrase role="reqattr">xml:id</phrase></loc> = ID
+  {<emph>any attribute in TT Style namespace</emph>}
+  {<emph>any attribute not in default or any TT namespace</emph>}&gt;
+  <emph>Content:</emph> <loc href="#element-vocab-group-metadata">Metadata.class</loc>*
+&lt;/isd:css&gt;
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p>For each arbitrary pair of <el>isd:css</el> child elements of an
+<loc href="#isd-vocabulary-isd"><el>isd:isd</el></loc> element,
+<emph>S1</emph> and <emph>S2</emph>, the set of specified styles of <emph>S1</emph> must
+not be the same as the set of specified styles of <emph>S2</emph>. For the purpose of comparing two
+sets of specified styles, the styles must be placed into a canonical order and then compared item
+by item for value equality, where the canonical order is in accordance to the qualified attribute name
+order, where each qualified name consists of a tuple <code>&lt;namespace URL, local name&gt;</code>,
+and such tuples are compared component-wise by case-sensitive lexical string order.</p>
+</div3>
+<div3 id="isd-vocabulary-region">
+<head>isd:region</head>
+<p>The <el>isd:region</el> element is used to represent a layout and presentation region
+and the content selected into that region, where that content takes the form of a
+<loc href="#document-structure-vocabulary-body">body</loc> element and its descendant TTML content elements.</p>
+<p>The <el>isd:region</el> element accepts as its children zero or more elements in the
+<loc href="#element-vocab-group-metadata"><code>Metadata.class</code></loc> element group,
+followed by zero or more <loc href="#animation-vocabulary-animate"><el>animate</el></loc> elements,
+followed by exactly one <loc href="#document-structure-vocabulary-body"><el>body</el></loc> element.</p>
+<table id="elt-syntax-isd-region" role="syntax">
+<caption>XML Representation &ndash; Element Information Item: isd:region</caption>
+<tbody>
+<tr>
+<td>
+<eg xml:space="preserve">
+&lt;isd:region
+  <loc href="#style-attribute-style">style</loc> = IDREF
+  <loc href="#metadata-attribute-role">ttm:role</loc> = <loc href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</loc>
+  <loc href="#content-attribute-xml-id"><phrase role="reqattr">xml:id</phrase></loc> = ID
+  {<emph>any attribute not in default or any TT namespace</emph>}&gt;
+  <emph>Content:</emph> <loc href="#element-vocab-group-metadata">Metadata.class</loc>*, <loc href="#animation-vocabulary-animate">animate</loc>*, <loc href="#document-structure-vocabulary-body">body</loc>
+&lt;/isd:region&gt;
+</eg>
+</td>
+</tr>
+</tbody>
+</table>
+<p>If the computed style set of the region represented by the <el>isd:region</el> element is not the
+set of initial style values that apply to <loc href="#layout-vocabulary-region"><el>region</el></loc>, then a
+<att>style</att> attribute must be specified which references an <loc href="#isd-vocabulary-css"><el>isd:css</el></loc> element that specifies the
+region's computed style set.</p>
+<p>The following constraints apply to the <loc href="#document-structure-vocabulary-body"><el>body</el></loc> element
+and its descendant elements:</p>
+<ulist>
+<item><p>no <att>animate</att> attribute is specified;</p></item>
+<item><p>no <att>begin</att> attribute is specified;</p></item>
+<item><p>no <att>dur</att> attribute is specified;</p></item>
+<item><p>no <att>end</att> attribute is specified;</p></item>
+<item><p>no <att>region</att> attribute is specified;</p></item>
+<item><p>no <att>timeContainer</att> attribute is specified;</p></item>
+<item><p>no attribute in the TT Style namespace is specified;</p></item>
+<item><p>no <loc href="#animation-vocabulary-set">set</loc> element is present;</p></item>
+<item><p>no significant text node, i.e., text node in a #PCDATA context, is not contained in a 
+<loc href="#content-vocabulary-span"><el>span</el></loc> element that contains no other child.</p></item>
+</ulist>
+<p>In addition, for the <loc href="#document-structure-vocabulary-body"><el>body</el></loc> element <emph>B</emph> and
+each of its descendant content elements <emph>C</emph>, if the computed style set of <emph>B</emph> or each <emph>C</emph> is
+not equal to the computed style set of its parent element, then that element, <emph>B</emph> or <emph>C</emph>, must specify a <att>style</att>
+attribute that references an <loc href="#isd-vocabulary-css"><el>isd:css</el></loc> element that specifies the
+element's computed style set.</p>
+</div3>
+</div2>
+<div2 id="isd-parameter-attribute-set">
+<head>ISD Parameter Attribute Set</head>
+<p>The following subset of the defined <loc href="#attribute-vocab-group-parameters">Parameter Attributes</loc>
+are available for use with an
+<loc href="#isd-vocabulary-sequence"><el>isd:sequence</el></loc> or
+<loc href="#isd-vocabulary-isd"><el>isd:isd</el></loc> element as described above:</p>
+<ulist>
+<item><p><loc href="#parameter-attribute-cellResolution">ttp:cellResolution</loc></p></item>
+<item><p><loc href="#parameter-attribute-frameRate">ttp:frameRate</loc></p></item>
+<item><p><loc href="#parameter-attribute-frameRateMultiplier">ttp:frameRateMultipler</loc></p></item>
+<item><p><loc href="#parameter-attribute-mediaOffset">ttp:mediaOffset</loc></p></item>
+<item><p><loc href="#parameter-attribute-pixelAspectRatio">ttp:pixelAspectRatio</loc></p></item>
+<item><p><loc href="#parameter-attribute-subFrameRate">ttp:subFrameRate</loc></p></item>
+<item><p><loc href="#parameter-attribute-tickRate">ttp:tickRate</loc></p></item>
+</ulist>
+</div2>
+<div2 id="isd-interchange">
+<head>ISD Interchange</head>
+<p>A concrete document instance that employs the <loc href="#isd">Intermediate Synchronic Document Syntax</loc> must be
+encoded as a well-formed <bibref ref="xml10"/> document using the UTF-8 character encoding. Furthermore, such a document must specify
+an <loc href="#isd-vocabulary-sequence"><el>isd:sequence</el></loc> element or
+an <loc href="#isd-vocabulary-isd"><el>isd:isd</el></loc> element as the root document element.</p>
+<p>When a resource consisting of a concrete ISD Sequence or ISD instance is interchanged and a media type is used to identify the content type
+of that resource, then the media type <code>application/ttml+xml</code> should be used, about which see <bibref ref="ttml1"/> Appendix C.
+If this media type is used, the optional <code>profile</code> parameter must not be specified, or, if specified, must be ignored by a processor.</p>
+</div2>
+<div2 id="isd-examples">
+<head>ISD Examples</head>
+<p><emph>This sub-section is non-normative.</emph></p>
+<ednote>
+<name>Add ISD Examples</name>
+<date>2014-09-22</date>
+<edtext>Add worked out examples of ISD Sequence and ISD document instances.</edtext>
+</ednote>
+</div2>
+</div1>
 <div1 id="references">
 <head>References</head>
 <p><emph>This appendix is normative.</emph></p>
@@ -19703,7 +20227,7 @@
 a requirement is partially satisfied, and <emph>N</emph> denotes a
 requirement is not satisfied.</p>
 <table id="requirements-table" role="common">
-<caption>Table I-1 &ndash; Requirement Satisfaction</caption>
+<caption>Table L-1 &ndash; Requirement Satisfaction</caption>
 <col width="10%"/>
 <col width="40%"/>
 <col width="10%"/>
@@ -20134,6 +20658,11 @@
 <p>This appendix provides information about the derivation of TTML
 vocabulary, separately describing derivation of elements and
 attributes.</p>
+<ednote>
+<name>Update Derivation</name>
+<date>2015-01-14</date>
+<edtext>Update derivation tables to include new vocabulary added in TTML2.</edtext>
+</ednote>
 <div2>
 <head>Element Derivation</head>
 <p>The first column of <specref ref="element-vocab-derivation-table"/>
@@ -20155,7 +20684,7 @@
 that is not specified for use with the <el>xhtml:div</el> model
 element.</p>
 <table id="element-vocab-derivation-table" role="common">
-<caption>Table J-1 &ndash; Elements</caption>
+<caption>Table M-1 &ndash; Elements</caption>
 <col width="20%"/>
 <col width="17%"/>
 <col width="13%" align="center"/>
@@ -20463,7 +20992,7 @@
 ref="element-vocab-derivation-table"/>
 above.</p>
 <table id="attribute-vocab-derivation-table" role="common">
-<caption>Table J-2 &ndash; Attributes</caption>
+<caption>Table M-2 &ndash; Attributes</caption>
 <col width="20%"/>
 <col width="17%"/>
 <col width="13%" align="center"/>
@@ -20944,7 +21473,7 @@
 <div2>
 <head>Requirements</head>
 <table id="qa-framework-requirements-table" role="common">
-<caption>Table K-1 &ndash; QA Framework Requirements Checklist</caption>
+<caption>Table N-1 &ndash; QA Framework Requirements Checklist</caption>
 <col width="76%"/>
 <col width="6%" align="center"/>
 <col width="6%" align="center"/>
@@ -21063,7 +21592,7 @@
 <div2>
 <head>Guidelines</head>
 <table id="qa-framework-guidelines-table" role="common">
-<caption>Table K-2 &ndash; QA Framework Guidelines Checklist</caption>
+<caption>Table N-2 &ndash; QA Framework Guidelines Checklist</caption>
 <col width="76%"/>
 <col width="6%" align="center"/>
 <col width="6%" align="center"/>
@@ -21326,392 +21855,6 @@
 capabilities model.</p>
 </note>
 </inform-div1>
-<div1 id="concrete-encoding">
-<head>Concrete Encoding</head>
-<p><emph>This appendix is normative.</emph></p>
-<p>In the absence of other requirements, a <loc href="#terms-document-instance">document instance</loc> should be concretely encoded as a
-well-formed XML 1.0 <bibref ref="xml10"/> document using the UTF-8 character encoding.</p>
-<note role="elaboration">
-<p>When using XML 1.0 <bibref ref="xml10"/> as the concrete encoding of TTML, only the following named character entities are defined:
-<code>&amp;amp;</code>, <code>&amp;apos;</code>, <code>&amp;gt;</code>, <code>&amp;lt;</code>, and <code>&amp;quot;</code>.</p>
-</note>
-</div1>
-<div1 id="time-expression-semantics">
-<head>Time Expression Semantics</head>
-<p><emph>This appendix is normative.</emph></p>
-<p>This appendix specifies the semantics for interpreting time expressions in <loc href="#terms-document-instance">document instances</loc>.</p>
-<note role="clarification">
-<p>The phrase <emph>local real time</emph> as used below is intended to model a virtual real time clock in the document processing context, where
-<emph>local</emph> means in the immediate proximity of the implementation of this processing context. The intent
-of defining relationships with this virtual clock is to establish a locally valid physical realization of time for didactic purposes.</p>
-</note>
-<note role="clarification">
-<p>The phrase <emph>play rate</emph> as used below is intended to model a (possibly variable) parameter in the document processing context wherein
-the rate of playback (or interpretation) of time may artificially dilated or narrowed, for example, when slowing down or speeding up the rate of
-playback of a <loc href="#terms-related-media-object">related media object</loc>. Without loss of generality, the following discussion assumes a fixed play(back) rate. In the case of
-variable play rates, appropriate adjustments may need to be made to the resulting computations.</p>
-</note>
-<div2 id="time-expression-semantics-clock">
-<head>Clock Time Base</head>
-<p>When operating with the <code>clock</code> time base, the following semantics apply for interpreting time expressions,
-as defined by <loc href="#timing-value-timeExpression">&lt;timeExpression&gt;</loc>, and their relationship to media time and local real time.</p>
-<p>The clock time base <phrase role="strong"><code>C</code></phrase> is related to local real time <phrase role="strong"><code>R</code></phrase>
-expressed in an arbitrary (implementation defined) epoch <phrase role="strong"><code>E</code></phrase>
-as follows:</p>
-<table id="clock-time-and-real-time" role="semantics">
-<caption>TTML Semantics &ndash; Clock Time and Real Time Relationship</caption>
-<tbody>
-<tr>
-<td>
-<slist>
-<sitem/>
-<sitem>
-<code>R = C + epochOffset + discontinuityOffset</code>
-</sitem>
-<sitem/>
-<sitem>
-where <code>C &isin; &real;</code>, <code>0 &le; C &lt; &infin;</code>, <code>C</code> in seconds since the most immediately prior midnight of the reference clock base;
-</sitem>
-<sitem/>
-<sitem>
-<code>epochOffset &isin; &real;</code>, <code>0 &le; epochOffset &lt; &infin;</code>, <code>epochOffset</code> in seconds, with 0 being the beginning
-of epoch <code>E</code>, and where the value of <code>epochOffset</code> is determined from the computed value of the <code>ttp:clockMode</code> parameter
-as follows:
-</sitem>
-<sitem/>
-<sitem>
-(1) if <code>local</code>, then the difference between the local real time at the most immediately prior local midnight and the local real time
-at the beginning of epoch <code>E</code>, expressed in seconds;
-</sitem>
-<sitem/>
-<sitem>
-(2) if <code>gps</code>, then the difference between the GPS time at the most immediately prior GPS midnight
-and the GPS time at the beginning of epoch <code>E</code>, expressed in seconds;
-</sitem>
-<sitem/>
-<sitem>
-(3) if <code>utc</code>, then the difference between the UTC time at the most immediately prior UTC midnight
-and the UTC time at the beginning of epoch <code>E</code>, expressed in seconds;
-</sitem>
-<sitem/>
-<sitem>
-<code>discontinuityOffset &isin; &real;</code>, <code>&minus;&infin; &lt; discontinuityOffset &lt; &infin;</code>, <code>discontinuityOffset</code> in seconds,
-and where the value of <code>discontinuityOffset</code> is equal to the sum of leap seconds (and fractions thereof) that have been added (or subtracted) since the
-most immediately prior midnight in the reference clock base;
-</sitem>
-<sitem/>
-<sitem>
-and <code>epochOffset</code> and <code>discontinuityOffset</code> are determined once and only once prior to the beginning of the <loc href="#terms-root-temporal-extent">root temporal extent</loc> such that
-during the period between value determination and the beginning of the <loc href="#terms-root-temporal-extent">root temporal extent</loc> there occurs no local midnight or reference clock base discontinuity.
-</sitem>
-<sitem/>
-</slist>
-</td>
-</tr>
-</tbody>
-</table>
-<p>Time value expressions, as denoted by a <loc href="#timing-value-timeExpression">&lt;timeExpression&gt;</loc>, are related to
-clock time <phrase role="strong"><code>C</code></phrase> as follows:</p>
-<table id="time-expressions-and-clock-time" role="semantics">
-<caption>TTML Semantics &ndash; Time Expressions and Clock Time Relationship</caption>
-<tbody>
-<tr>
-<td>
-<slist>
-<sitem/>
-<sitem>
-If a time expression uses the <emph>clock-time</emph> form or an <emph>offset-time</emph> form that doesn't use the ticks (<code>t</code>) metric, then:
-</sitem>
-<sitem/>
-<sitem>
-<code>C = 3600 * hours + 60 * minutes + seconds</code>
-</sitem>
-<sitem/>
-<sitem>
-where
-<code>hours</code>,
-<code>minutes</code>,
-<code>seconds</code> components are extracted from time expression if present, or zero if not present.
-</sitem>
-<sitem/>
-<sitem>
-Otherwise, if a time expression uses an <emph>offset-time</emph> form that uses the ticks (<code>t</code>) metric, then:
-</sitem>
-<sitem/>
-<sitem>
-<code>C = ticks / tickRate</code>
-</sitem>
-<sitem/>
-</slist>
-</td>
-</tr>
-</tbody>
-</table>
-<note role="clarification">
-<p>The <emph>frames</emph> and <emph>sub-frames</emph> terms and the frames (<code>f</code>) metric of time expressions do not apply when using
-the <code>clock</code> time base.</p>
-</note>
-<p>The clock time base <phrase role="strong"><code>C</code></phrase> is independent of media time <phrase role="strong"><code>M</code></phrase>:</p>
-<table id="clock-time-and-media-time" role="semantics">
-<caption>TTML Semantics &ndash; Clock Time and Media Time Relationship</caption>
-<tbody>
-<tr>
-<td>
-<slist>
-<sitem/>
-<sitem>
-<code>M &not;&prop; C</code>
-</sitem>
-<sitem/>
-</slist>
-</td>
-</tr>
-</tbody>
-</table>
-<note role="elaboration">
-<p>That is to say, timing is disconnected from (not necessarily proportional to) media time when
-the <code>clock</code> time base is used. For example, if the media play rate is zero (0), media playback is suspended; however, timing coordinates
-will continue to advance according to the natural progression of clock time in direct proportion to the reference clock base. Furthermore, if the media play rate changes
-during playback, presentation timing is not affected.
-</p>
-</note>
-</div2>
-<div2 id="time-expression-semantics-media">
-<head>Media Time Base</head>
-<p>When operating with the <code>media</code> time base, the following semantics apply for interpreting time expressions,
-as defined by <loc href="#timing-value-timeExpression">&lt;timeExpression&gt;</loc>, and their relationship to media time and local real time.</p>
-<p>The media time base <phrase role="strong"><code>M</code></phrase> is related to local real time <phrase role="strong"><code>R</code></phrase>
-expressed in an arbitrary (implementation defined) epoch <phrase role="strong"><code>E</code></phrase> as follows:</p>
-<table id="media-time-and-real-time" role="semantics">
-<caption>TTML Semantics &ndash; Media Time and Real Time Relationship</caption>
-<tbody>
-<tr>
-<td>
-<slist>
-<sitem/>
-<sitem>
-<code>R = playRate * M + epochOffset</code>
-</sitem>
-<sitem/>
-<sitem>
-where <code>M &isin; &real;</code>, <code>0 &le; M &lt; &infin;</code>, <code>M</code> in seconds, with 0 corresponding to the beginning of the <loc href="#terms-root-temporal-extent">root temporal extent</loc>;
-</sitem>
-<sitem/>
-<sitem>
-<code>playRate &isin; &real;</code>, <code>&minus;&infin; &lt; playRate &lt; &infin;</code>, <code>playRate</code> is unit-less, and where the value of
-<code>playRate</code> is determined by the document processing context;
-</sitem>
-<sitem/>
-<sitem>
-and <code>epochOffset &isin; &real;</code>, <code>0 &le; epochOffset &lt; &infin;</code>, <code>epochOffset</code> in seconds, with 0 corresponding to the beginning of
-an epoch <code>E</code>, and where the value of <code>epochOffset</code> is the difference between the local real time at the beginning of the
-<loc href="#terms-root-temporal-extent">root temporal extent</loc> and the local real time at the the beginning of epoch <code>E</code>, expressed in seconds.
-</sitem>
-</slist>
-</td>
-</tr>
-</tbody>
-</table>
-<p>Time value expressions, as denoted by a <loc href="#timing-value-timeExpression">&lt;timeExpression&gt;</loc>, are related to
-media time <phrase role="strong"><code>M</code></phrase> in accordance to the
-<code>ttp:frameRate</code>, <code>ttp:subFrameRate</code>, and <code>ttp:frameRateMultipler</code> parameters as follows:</p>
-<table id="time-expressions-and-media-time" role="semantics">
-<caption>TTML Semantics &ndash; Time Expressions and Media Time Relationship</caption>
-<tbody>
-<tr>
-<td>
-<slist>
-<sitem/>
-<sitem>
-If a time expression uses a <emph>clock-time</emph> form or an <emph>offset-time</emph> form that doesn't use the ticks (<code>t</code>) metric, then:
-</sitem>
-<sitem/>
-<sitem>
-<code>
-M = referenceBegin + 3600 * hours + 60 * minutes + seconds + ((frames + (subFrames / subFrameRate)) / effectiveFrameRate)
-</code>
-</sitem>
-<sitem/>
-<sitem>
-where <code>referenceBegin</code> is determined according to whether the nearest ancestor time container employs
-parallel (<code>par</code>) or sequential (<code>seq</code>) semantics: if parallel or if sequential and no prior sibling
-timed element exists, then <code>referenceBegin</code>
-is the media time that corresponds to the beginning of the nearest ancestor time container or
-zero (0) if this time container is the <loc href="#terms-root-temporal-extent">root temporal extent</loc>; otherwise, if sequential and a prior sibling
-timed element exists, then <code>referenceBegin</code> is the media time that corresponds to the active end of the
-immediate prior sibling timed element;
-</sitem>
-<sitem/>
-<sitem>
-the <code>hours</code>, <code>minutes</code>, <code>seconds</code>, <code>frames</code>, <code>subFrames</code> components
-are extracted from time expression if present, or zero if not present;
-</sitem>
-<sitem/>
-<sitem>
-<code>subFrameRate</code> is the computed value of the <att>ttp:subFrameRate</att> parameter;
-</sitem>
-<sitem/>
-<sitem>
-and <code>effectiveFrameRate</code> (in frames per second) is <code>frameRate * frameRateMultipler</code> where
-<code>frameRate</code> is the computed value of the <att>ttp:frameRate</att> parameter and
-<code>frameRateMultipler</code> is the computed value of the <att>ttp:frameRateMultiplier</att> parameter.
-</sitem>
-<sitem/>
-<sitem>
-Otherwise, if a time expression uses an <emph>offset-time</emph> form that uses the ticks (<code>t</code>) metric, then:
-</sitem>
-<sitem/>
-<sitem>
-<code>
-M = referenceBegin + ticks / tickRate
-</code>
-</sitem>
-<sitem/>
-<sitem>
-where <code>referenceBegin</code> is as described above;
-</sitem>
-<sitem/>
-<sitem>
-the <code>ticks</code> component is extracted from time expression;
-</sitem>
-<sitem/>
-<sitem>
-and <code>tickRate</code> is the computed value of the <att>ttp:tickRate</att> parameter;
-</sitem>
-<sitem/>
-</slist>
-</td>
-</tr>
-</tbody>
-</table>
-<note role="elaboration">
-<p>If the computed <code>frameRateMultipler</code> ratio is not integral, then <code>effectiveFrameRate</code> will be a non-integral rational.</p>
-</note>
-<note role="clarification">
-<p>The begin time of the <loc href="#terms-root-temporal-extent">root temporal extent</loc> is related to the begin time of a
-<loc href="#terms-related-media-object">related media object</loc> in accordance with the computed value of the
-<loc href="#parameter-attribute-mediaOffset"><att>ttp:mediaOffset</att></loc> parameter property.</p>
-</note>
-</div2>
-<div2 id="time-expression-semantics-smpte">
-<head>SMPTE Time Base</head>
-<p>When operating with the <code>smpte</code> time base, the following semantics apply for interpreting time expressions,
-as defined by <loc href="#timing-value-timeExpression">&lt;timeExpression&gt;</loc>, and their relationship to media time and local real time.</p>
-<p>If the computed value of the <att>ttp:markerMode</att> parameter is <code>discontinuous</code>, then there is no direct relationship between
-time expressions and media time <phrase role="strong"><code>M</code></phrase> or local real time <phrase role="strong"><code>R</code></phrase>. In
-this case, time expressions refer to synchronization events (markers) emitted by the <loc href="#terms-document-processing-context">document processing context</loc>
-when <loc href="#terms-smpte-time-code">smpte time codes</loc>
-are encountered in the <loc href="#terms-related-media-object">related media object</loc>.</p>
-<p>Otherwise, if the computed value of the <att>ttp:markerMode</att> parameter is <code>continuous</code>, then the relationships between time expressions and
-local real time and media time are as described below in terms of a <loc href="#terms-synthetic-smpte-document-syncbase">synthetic smpte document syncbase</loc>, here referred to as the
-SMPTE time base <phrase role="strong"><code>S</code></phrase>.</p>
-<table id="time-expressions-and-smpte-time" role="semantics">
-<caption>TTML Semantics &ndash; Time Expressions and SMPTE Time Relationship</caption>
-<tbody>
-<tr>
-<td>
-<slist>
-<sitem/>
-<sitem>
-<code>S = (countedFrames - droppedFrames + (subFrames / subFrameRate)) / effectiveFrameRate</code>
-</sitem>
-<sitem/>
-<sitem>where</sitem>
-<sitem/>
-<sitem>
-<code>countedFrames = (3600 * hours + 60 * minutes + seconds) * frameRate + frames</code>
-</sitem>
-<sitem/>
-<sitem>
-<code>hours</code>, <code>minutes</code>, <code>seconds</code>, <code>frames</code>, <code>subFrames</code> components
-are extracted from time expression if present, or zero if not present;
-</sitem>
-<sitem/>
-<sitem>
-<code>droppedFrames</code> is computed as follows:
-</sitem>
-<sitem/>
-<sitem>
-1. let <emph>dropMode</emph> be the computed value of the <att>ttp:dropMode</att> parameter;
-</sitem>
-<sitem/>
-<sitem>
-2. if <emph>dropMode</emph> is <code>dropNTSC</code>, let
-<code>droppedFrames = (hours * 54 + floor(minutes - minutes/10)) * 2</code>;
-</sitem>
-<sitem/>
-<sitem>
-3. otherwise, if <emph>dropMode</emph> is <code>dropPAL</code>, let
-<code>droppedFrames = (hours * 27 + floor(minutes/2 - minutes/20)) * 4</code>;
-</sitem>
-<sitem/>
-<sitem>
-4. otherwise, let
-<code>droppedFrames = 0</code>;
-</sitem>
-<sitem/>
-<sitem>
-<code>frameRate</code> is the computed value of the <att>ttp:frameRate</att> parameter;
-</sitem>
-<sitem/>
-<sitem>
-<code>subFrameRate</code> is the computed value of the <att>ttp:subFrameRate</att> parameter;
-</sitem>
-<sitem/>
-<sitem>
-and <code>effectiveFrameRate</code> (in frames per second) is <code>frameRate * frameRateMultipler</code> where
-<code>frameRate</code> is the computed value of the <att>ttp:frameRate</att> parameter and
-<code>frameRateMultipler</code> is the computed value of the <att>ttp:frameRateMultiplier</att> parameter.
-</sitem>
-<sitem/>
-<sitem>
-Notwithstanding the above, if a time expression contains a frame code that is designated as
-dropped according to <specref ref="parameter-attribute-dropMode"/>, then that time expression
-must be considered to be invalid for purposes of validation assessment.
-</sitem>
-<sitem/>
-</slist>
-</td>
-</tr>
-</tbody>
-</table>
-<p>The SMPTE time base <phrase role="strong"><code>S</code></phrase> is related to the media time base <phrase role="strong"><code>M</code></phrase> as follows:</p>
-<table id="smpte-time-and-media-time" role="semantics">
-<caption>TTML Semantics &ndash; SMPTE Time and Media Time Relationship</caption>
-<tbody>
-<tr>
-<td>
-<slist>
-<sitem/>
-<sitem>
-<code>M = referenceBegin + S</code>
-</sitem>
-<sitem/>
-<sitem>
-where <code>referenceBegin</code> is determined according to whether the nearest ancestor time container employs
-parallel (<code>par</code>) or sequential (<code>seq</code>) semantics: if parallel or if sequential and no prior sibling
-timed element exists, then <code>referenceBegin</code>
-is the SMPTE time that corresponds to the beginning of the nearest ancestor time container or
-zero (0) if this time container is the <loc href="#terms-root-temporal-extent">root temporal extent</loc>; otherwise, if sequential and a prior sibling
-timed element exists, then <code>referenceBegin</code> is the SMPTE time that corresponds to the active end of the
-immediate prior sibling timed element;
-</sitem>
-<sitem/>
-</slist>
-</td>
-</tr>
-</tbody>
-</table>
-<p>Given the derived media time base as described above, then 
-media time base <phrase role="strong"><code>M</code></phrase> is related to the local real time <phrase role="strong"><code>R</code></phrase>
-as described in <specref ref="time-expression-semantics-media"/> above.</p>
-<note role="clarification">
-<p>The begin time of the <loc href="#terms-root-temporal-extent">root temporal extent</loc> is related to the begin time of a
-<loc href="#terms-related-media-object">related media object</loc> in accordance with the computed value of the
-<loc href="#parameter-attribute-mediaOffset"><att>ttp:mediaOffset</att></loc> parameter property.</p>
-</note>
-</div2>
-</div1>
 <inform-div1 id="common-styling">
 <head>Common Caption Style Examples</head>
 <p>This section provides examples of the following common caption styles using TTML Content