Change sections are ordered from most recent to least recent; within each section changes are divided into technical and editorial and further ordered by where they occur within the specification document.
Technical Changes * In 2.2, add definition of terms: anonymous span, area, block area, combined profile, inline area, line area, non-combined profile, profile fragment identifier, profile processing, timed element, validation processing, and validation processor. * In 3.2.1, insert new step (3) under Generic Processor Conformance in order to invoke profile processing. * In 3.3, add use of 'ttp:contentProfiles' and 'ttp:processorProfiles' to criteria for compliance claims on document instances. * In 5.2.4.{2,3}, instead of 'mostRestrictive' for the purpose of determining the profile combination method to be used when combining multiple top-level profiles, use the computed value of the 'ttp:{content,processor}ProfileCombination' attributes, respectively. * In 5.4.1, add 'xml:base' attribute to Core Attributes in Table 5-5. * In 5.4.1, add 'tts:lineShear' and 'tts:shear' to Styling Attributes in Table 5-5. * In 6.1.1, allow conformant processor to not support profile combination (a combined profile) and/or profile nesting (a nesting profile). * In 6.1.2 and 6.1.4, constrain value syntax of 'xml:base' to <uri> value syntax. * In 6.2.2, add 'ignore' token value for 'ttp:contentProfileCombination' and make 'ignore' the fallback default value. * In 6.2.4, change the fallback default value of 'ttp:inferProcessorProfileSource' from 'combine' to 'first'. * In 6.2.9, add 'ignore' token value for 'ttp:processorProfileCombination' and make 'ignore' the fallback default value. * In 6.2.11, allow validation abort processing to be overridden by end-user or application. * In 8.1.1, remove 'condition' attribute from 'tt' element. * In 8.1.3, restore erroneously removed declaration of use of TTML style attributes on 'body' element. * In 8.1.6, add prose describing use of anonymous spans that is analogous to like prose found in 8.1.5 (defining 'p' element). * In 8.2, add 'xml:base' attribute to content attribute vocabulary, and, in all element definitions that did not previously allow 'xml:base', add support for use of 'xml:base' attribute except for 'ttp:feature' and 'ttp:extension elements. * In 8.2.1, define exceptions to ignoring semantics on conditionally excluded element. * In 8.2.7, define generic use of 'xml:base' attribute. * In 8.3, add content value syntax definitions for: <absolute-profile-designator>, <absolute-uri>, <fragment-profile-designator>, <fragment-uri>, <profile-designator>, <relative-profile-designator>, and <relative-uri>. * In 9.1.4, specify optional use of deferred downloading of font resources. * In 10.1.1, handle the case of multiple 'initial' elements applying to a single style property. * In 10.2, add 'tts:lineShear' styling attribute (10.2.28). * In 10.2, add 'tts:shear' styling attribute (10.2.39). * In 10.2.17, remove 'p' from applies row of property definition table for 'tts:fontFamily'. * In 10.2.17, add prose noting that 'tts:fontFamily' is used to resolve the value of 'normal' for 'tts:lineHeight' on 'p' element. * In 10.2.18, remove 'p' from applies row of property definition table for 'tts:fontKerning'. * In 10.2.20, remove 'p' from applies row of property definition table for 'tts:fontShear'. * In 10.2.21, remove 'p' from applies row of property definition table for 'tts:fontSize'. * In 10.2.21, add prose noting that 'tts:fontSize' is used to resolve the value of 'normal' for 'tts:lineHeight' on 'p' element. * In 10.2.22, remove 'p' from applies row of property definition table for 'tts:fontStyle'. * In 10.2.22, add prose noting that 'tts:fontStyle' is used to resolve the value of 'normal' for 'tts:lineHeight' on 'p' element. * In 10.2.23, remove 'p' from applies row of property definition table for 'tts:fontVariant'. * In 10.2.23, add prose noting that 'tts:fontVariant' is used to resolve the value of 'normal' for 'tts:lineHeight' on 'p' element. * In 10.2.24, remove 'p' from applies row of property definition table for 'tts:fontWeight'. * In 10.2.24, add prose noting that 'tts:fontWeight' is used to resolve the value of 'normal' for 'tts:lineHeight' on 'p' element. * In 10.2.27, add use of 'tts:fontVariant' in step (4) of 'normal' computations. * In 10.2.27, indicate that fallback of 125% for 'normal' value of 'tts:lineHeight' is implementation dependent. * In 10.2.29, make 'tts:luminanceGain' non-inheritable, and add prose qualifying applicability to pixels in a region. * In 10.2.35, change 'tts:ruby' to non-animatable. * In 10.2.35.1, add inline definitions of concepts "isolated ruby content", "implied ruby base container", and "implied ruby text container". * In 10.2.37, clarify and constrain semantic applicability of 'tts:rubyPosition'. * In 10.2.38, redefine semantics of '<length>' component of 'tts:rubyReserve' to be based on the semantics of 'tts:fontSize' that would apply to ruby text content. * In 10.2.38, clarify semantics of 'tts:rubyReserve' when ruby text content is (also) present. * In 10.2.40, remove 'digits' expression from 'tts:textCombine'; specify (default) fallback value of 'none'. * In 10.2.46, clarify 'tts:textOutline' that the (default) fallback value for blur radius is '0px'. * In 10.3.3, change semantics of 'outside' keyword for '<annotation-position>' value syntax to apply 'before' semantics for only first (or only) line, and 'after' semantics for remaining lines. * In 10.3.33, constrain syntax for one-component and two-component values of '<position>' to enhance compatibility with CSS. * In 10.3.35, clarify '<shadow>' that the (default) fallback value for blur radius is '0px'. * In 10.3.36, remove 'digits' expression from '<text-combine>'. * In 10.3.40, change '<text-shadow>' value syntax to use COMMA as delimiter instead of whitespace in a list of '<shadow>' expressions. * In 12.2.4, remove deprecation of sequential time container in the context of using discontinuous smpte mode timing. * In 12.3.1, remove optionality for the metric component of a '<time-expression>', which restores TTML1 syntax in this regard. * In 13.1.1, add clarifications and constraints pertaining to the semantics of 'accumulate', 'additive', 'keySplines', 'keyTimes' and 'repeatCount'. * In 13.3.2, require that '<animation-value-list>' contain two or more '<animation-value>' components instead of one or more such components. * In 13.3.3, add 'paced' keyword to '<calculation-mode>'. * In 13.3.7, allow '<repeat-count>' to take fractional values. * In Appendix E.1, add the following feature designators: #animate-minimal, #animate-paced, #animate-spline, #base, #base-general, #base-version-2, #condition-fn-media, #condition-fn-parameter, #condition-fn-supports, #condition-primary, #contentProfiles-combined, #display-version-2, #extent-auto, #extent-auto-version-2, #extent-contain, #extent-cover, #extent-full-version-2, #extent-length, #extent-length-version-2, #extent-region-version-2, #extent-root-version-2, #image-png, #length-root-container-relative, #length-version-2, #lineShear #opacity-block, #opacity-inline, #opacity-region, #opacity-version-2, #processorProfiles-combined, #profile-full-version-2, #profile-nesting, #region-implied-animation, #rubyAlign-minimal, #shear, #textEmphasis-color, #textEmphasis-quoted-string, #unicodeBidi-version-2, #visibility-image, #visibility-version-2, and #xlink. * In Appendix E.1, remove the following feature designators: #animate-calculation-mode, #animate-key-splines, #animate-key-times, #condition-media, #extent-block, #fontFamily-p, #fontSize-p, #fontStyle-p, #fontWeight-p, #inferProcessorProfile, #region-inline-explicit, #region-inline-implicit, #textEmphasis-no-color, #textEmphasis-no-quoted-string. * In Appendix J.1, add certain core attributes missing from 'isd:sequence', 'isd:isd', 'isd:css', and 'isd:region'. * In Appendix K, add normative reference [PNG]. * Throughout, except for 'ttp:feature' and 'ttp:extension elements, add support for use of 'xml:base' attribute on all element types that did not previously support its use. Editorial Changes * In 2.2, revise definition of terms: content profile, effective content profile, effective processor profile, glyph area, nesting profile, non-nesting profile, processor profile, profile, validating content processor, * In 2.3, clarify use of '@' prefix when used with attribute names. * In 3, constrain 'TTML' to 'TTML2' as needed to correctly scope specification text. * In 3.2, add introductory paragraph in prologue. * In 3.2.1, remove misleading language in notes pertaining to scope of mandatory and optional semantics. * In 3.3, add note clarifying scope of profile support for compliance claims on processors. * In 5.2.1, restore use of 'ttp:profile' attribute in prose description of techniques available for use when declaring a processor profile. * In 5.2.4, change name of 'profile' profile state object to 'profile instance' to avoid conflict with more general uses of the term 'profile'. * In 8.1.5, add reference to [construct anonymous spans] procedure in prose describing use of anonymous span. * In 10, combine (non-audio) style attributes and audio style attributes into same section, which has a side effect of renumbering all 10.4.* subsections as 10.3.* subsections. * In 10, collapse language regarding applicability of a style property to span and, thus, to anonymous spans. * In 10.2.16, add note clarifying the distinction between 'auto' and 'auto auto' values of 'tts:extent'. * In 10.2.20, move prose defining shear calculations to 10.4.5.3 in order to share common definition with the three different shear related style properties. * In 10.2.27, add note referring to new section 11.3.2.2 on line stacking with respect to the phrase "line height". * In 10.2.27, add note indicating that 'tts:lineHeight', in addition to applying to the 'p' element, is used in resolving the half-leading of inline areas produced by spans. * In 10.2.27, add to note that treatment of 'tts:lineHeight' is intended to be compatible with XSL-FO and CSS. * In 10.2.34, clarify explanation of example fragment. * In 10.2.35, reorganize presentation of constraints that pertain to the use of 'tts:ruby'. * In 10.2.35, add note that inline areas generated by ruby text containers and ruby text content are descendants of the same line area that contains its associated ruby base content. * In 10.2.36, clarify semantic applicability of 'tts:rubyAlign'. * In 10.3.34, remove obsolete keywords 'auto', 'between', 'around', and rewrite syntax to use '<annotation-position>'. * In 11.3.2, Line Layout, divide content into two sub-sections, placing the original content into 11.3.2.1 and adding a new subsection 11.3.2.2 containing a non-normative description of line stacking. * In 14, add prose (and note) clarifying that no presentation semantics apply to metadata. * In Appendix E, recommend (non-normatively) that implementations parse known syntax even if some of that syntax is not supported semantically speaking. * In Appendix E.1, clarify usage of phrase "all defined values." * In Appendix G, update profile documents to reflect additions and removal of feature designators in E.1. * In Appendix G, add '@extends' attribute for features defined as syntactic or semantic extensions in E.1. * In Appendix L, add non-normative references [Data Scheme], [DVBSS], and [PG PNG]. * In Appendix M, update requirement satisfaction information. * In Appendix N, update vocabulary derivation information. * In Appendix U, update new vocabulary information. * Throughout, update citations as needed in internal and external specification references, term references, and other forms of concept references. * Throughout, add or update explicit links to term definitions when term is referenced in text. * Throughout, minor improvements to language and correction of typos. * Throughout, make reference to [SRGB] when referring to RGB color space. * Update schemas as required to adhere to specification revisions.
Technical Changes * In 3.2.1, add performance of document validation. * In 5, insert new section 5.3, defining normative validation semantics. * In 5.1, add TT Intermediate Synchronic Document Namespace to Table 5-1. * In 5.2, add TTML2 (transformation, presentation, full) profiles. * In 5.2, specify profile state concepts and algorithm semantics in detail. * In 5.2, change profile defaulting to be dependent upon primary function of content processor, i.e., presentation vs transformation; e.g., if defaulting for a presentation processor, then use a presentation profile as a default not a transformation profile. * In 5.4.1, add new vocabulary: 'animate', 'animation', 'audio', 'chunk', 'data', 'font', 'image', 'initial', 'source', 'resources', and 'ttm:item' to Table 5-3. * In 5.4.1, add new profile attribute vocabulary 'ttp:contentProfiles', 'ttp:contentProfileCombination', 'ttp:inferProcessorProfileMethod', 'ttp:inferProcessorProfileSource', 'ttp:permitFeatureNarrowing', 'ttp:permitFeatureWidening', 'ttp:processorProfiles', 'ttp:processorProfileCombination', 'ttp:validation', and 'ttp:validationAction' to Table 5-5. * In 5.3.1, add new parameter attribute vocabulary 'ttp:displayAspectRatio' to Table 5-5. * In 5.4.1, add new animation vocabulary, 'animate', to Animation.class in Table 5-4. * In 5.4.1, add new 'ttm:item' to to Metadata.class in Table 5-4. * In 5.4.1, add new styling attribute vocabulary 'tts:backgroundClip', 'tts:backgroundExtent', 'tts:backgroundImage', 'tts:backgroundOrigin', 'tts:backgroundPosition', 'tts:backgroundRepeat', 'tts:border', 'tts:bpd', 'tts:disparity', 'tts:fontKerning', 'tts:fontSelectionStrategy', 'tts:fontShear', 'tts:fontVariant', 'tts:ipd', 'tts:letterSpacing', 'tts:luminanceGain', 'tts:position', 'tts:ruby', 'tts:rubyAlign', 'tts:rubyOverflow', 'tts:rubyOverhang', 'tts:rubyOverhangClass', 'tts:rubyPosition', 'tts:rubyReserve', 'tts:textCombine', 'tts:textEmphasis', 'tts:textOrientation', and 'tts:textShadow' to Table 5-5. * In 5.4.1, add new animation binding attribute vocabulary, 'animate', to Table 5-5. * In 5.4.1, add new data attributes vocabulary, 'encoding', 'format', 'src', and 'type' to Table 5-5. * In 5.3.1, add new Conditionalization Attribute vocabulary, 'condition', to Table 5-5. * In 5.3.1, add new Linking Attribute vocabulary, 'xlink:*', to Table 5-5. * In 6.1.1, add support for nesting profiles by changing content model of ttp:profile to permit either (1) a list of features/extensions or (2) a list of nested profiles. * In 6.1.1, add 'combine' attribute to ttp:profile element, including normative processing semantics. * In 6.1.1, add 'designator' attribute to ttp:profile element in order to normatively associate a profile designator with a profile definition. * In 6.1.3, obsolete 'use' value for 'value' attribute, and, if used, requires decoder to intepret as if 'required' had been specified. * In 6.1.3, add 'prohibited' value to 'value' attribute of ttp:feature element, including normative processing semantics. * In 6.1.3, change default for 'value' attribute to be dependent upon profile type (processor or profile). * In 6.1.3, add optional 'extends' and 'restricts' attributes to the ttp:feature element in order to express superset/subset relations between a feature and another feature. * In 6.1.5, obsolete 'use' value for 'value' attribute, and, if used, requires decoder to intepret as if 'required' had been specified. * In 6.1.5, add 'prohibited' value to 'value' attribute of ttp:extension element, including normative processing semantics. * In 6.1.5, change default for 'value' attribute to be dependent upon profile type (processor or profile). * In 6.1.5, add optional 'extends' and 'restricts' attributes to the ttp:extension element in order to express superset/subset relations between an extension and another feature or extension. * In 6.2, add 'ttp:contentProfiles' parameter attribute. * In 6.2, add 'ttp:contentProfileCombination' parameter attribute. * In 6.2, add 'ttp:inferProcessorProfileMethod' parameter attribute. * In 6.2, add 'ttp:inferProcessorProfileSource' parameter attribute. * In 6.2, add 'ttp:permitFeatureNarrowing' parameter attribute. * In 6.2, add 'ttp:permitFeatureWidening' parameter attribute. * In 6.2, add 'ttp:processorProfiles' parameter attribute. * In 6.2, add 'ttp:processorProfileCombination' parameter attribute. * In 6.2, add 'ttp:validation parameter attribute. * In 6.2, add 'ttp:validationAction parameter attribute. * In 6.2.7, deprecate 'ttp:profile' parameter attribute, replacing it with 'ttp:processorProfiles' parameter attribute. * In 8.1.1, add explicit tts:position style property support to 'tt' element * In 8.1.2, add new 'animation' container element as optional child of 'head' element. * In 8.1.3, add 'animate' attribute to 'body' element. * In 8.1.4, extend content model of 'div' to permit zero or one 'region' element child (in the Layout.class) prior to any content element. * In 8.1.4, specify semantics of using 'tts:extent', 'tts:origin' and 'tts:position' with 'div' element to imply an anonymous inline region. * In 8.1.4, add 'animate' attribute to 'div' element. * In 8.1.4, extend content model of 'div' to permit the use of embedded content 'audio' and 'image' element children. * In 8.1.5, extend content model of 'p' to permit zero or one 'region' element child (in the Layout.class) prior to any content element. * In 8.1.5, specify semantics of using 'tts:extent', 'tts:origin' and 'tts:position' with 'p' element to imply an anonymous inline region. * In 8.1.5, add 'animate' attribute to 'p' element. * In 8.1.5, extend content model of 'p' to permit the use of embedded content 'audio' and 'image' element children. * In 8.1.6, add 'animate' attribute to 'span' element. * In 8.1.6, extend content model of 'span' to permit the use of embedded content 'audio' and 'image' element children. * In 8.1.6, add use of 'xlink:*' attributes to provide linking semantics. * In 8.2, add 'condition' attribute. * In 8.2, add 'xlink:arcrole', 'xlink:href', 'xlink:role', 'xlink:show', and 'xlink:title' attributes, applicable to span and image element types. * Insert new top-level section 9, defining embedded content element types: audio, chunk, data, font, image, resources, source. * Insert new subsection 10.1.1, defining 'initial' element type used to redefine initial value of style property(ies). * In 10.1.2, add Metadata.class children to 'style' element. * In 10.2, add 'tts:backgroundClip' styling attribute. * In 10.2, add 'tts:backgroundExtent' styling attribute. * In 10.2, add 'tts:backgroundImage' styling attribute. * In 10.2, add 'tts:backgroundOrigin' styling attribute. * In 10.2, add 'tts:backgroundPosition' styling attribute. * In 10.2, add 'tts:backgroundRepeat' styling attribute. * In 10.2, add 'tts:border' styling attribute. * In 10.2, add 'tts:bpd' styling attribute. * In 10.2, add 'tts:disparity styling attribute. * In 10.2, add 'tts:fontKerning' styling attribute. * In 10.2, add 'tts:fontSelectionStrategy' styling attribute. * In 10.2, add 'tts:fontShear' styling attribute. * In 10.2, add 'tts:fontVariant' attribute. * In 10.2, add 'tts:ipd' styling attribute. * In 10.2, add 'tts:letterSpacing' styling attribute. * In 10.2, add 'tts:luminance styling attribute. * In 10.2, add 'tts:position' styling attribute. * In 10.2, add 'tts:ruby' styling attribute. * In 10.2, add 'tts:rubyAlign' styling attribute. * In 10.2, add 'tts:rubyOverhang' styling attribute. * In 10.2, add 'tts:rubyOverhangClass' styling attribute. * In 10.2, add 'tts:rubyOverflow' styling attribute. * In 10.2, add 'tts:rubyPosition' styling attribute. * In 10.2, add 'tts:rubyReserve' styling attribute. * In 10.2, add 'tts:textCombine' styling attribute. * In 10.2, add 'tts:textEmphasis' styling attribute. * In 10.2, add 'tts:textOrientation' styling attribute. * In 10.2, add 'tts:textShadow' styling attribute. * In 10.2 prologue, add proscription against specifying non-applicable, non-inheritable style attributes on stylable elements. * In 10.2.1, add 'image' and 'set' elements to enumeration of element types to which 'style' attribute applies. * In 10.2.16, add 'div' and 'p' elements to enumeration of element types to which tts:extent applies. Define semantics that causes the use of tts:extent to generate an implied inline region. * In 10.2.16, add 'contain' and 'cover' values to tts:extent. * In 10.2.17, add 'p' element to enumeration of element types to which tts:fontFamily applies. * In 10.2.21, add 'p' element to enumeration of element types to which tts:fontSize applies. Clarify that "1em" is equivalent to "100%". * In 10.2.22, add 'p' element to enumeration of element types to which tts:fontStyle applies. * In 10.2.24, add 'p' element to enumeration of element types to which tts:fontWeight applies. * In 10.2.27, specify algorithm for resolving the 'normal' value of tts:lineHeight that takes into account the use of per-font-metrics for ascent, descent, and line gap, using 125% of font size as a fall back. * In 10.2.28, add content elements to enumeration of element types to which tts:opacity applies. * In 10.2.29, add 'div' and 'p' elements to enumeration of element types to which tts:origin applies. Define semantics that causes the use of tts:origin to generate an implied inline region. * In 10.2.31, add content elements to enumeration of element types to which tts:padding applies. * In 10.2.45, add 'span' to enumeration of element types to which tts:textAlign applies. * In 10.2.45, add 'justify' keyword value to tts:textAlign. * In 10.3, add <border-color>, <border-style>, <border-thickness>, <character-class>, <emphasis-color>, <emphasis-position>, <emphasis-style>, <lwsp>, <measure>, <named-character-class>, <non-negative-integer>, <number>, <percentage>, and <position>, <shadow>, <whitespace> value expressions. * In 10.3.12, add 'rw' and 'rh' units of measure in order to express lengths as a percentage of the root container region. * In 10.4.4, add semantics for determining specified style set and computed style set for 'set' element. * In 10.4.4.2, rework SSS(E) processing algorithm to properly account for inheritable and non-inheritable properties and use of specified initial value overrides. * In 10.13.14, make units component of a <length> expression optional, which, if absent, is interpreted as if 'px' were specified. * In 11.1.2, require out-of-line region to specify 'xml:id' attribute. * In 11.3.1, qualify default region in terms of out-of-line region(s). * In 11.3.2, define inline region processing semantics. * In 12.2.2, specify that a duration (@dur) of zero is explicitly permitted. * In 12.3.1, make metric component of a <time-epression> expression optional, which, if absent, is interpreted as if 's' were specified. * In 12.3.1, add wallclock-time form of <time-epression> in order to express time with an explicit date. * In 13.1.1, add 'animation' element in order to support out-of-line animation specifications. * In 13.1.2, add 'animate' element. * In 13.1.3, add 'style' attribute to 'set' element. * In 13.1.3, permit multiple attributes from TT Style Namespace on 'set' element. * In 13.1.3, add 'fill' and 'repeatCount' attributes to 'set' element for symmetry with 'animate'. * In 13.2.1, add definition of 'animate' attribute in order to perform binding between content elements and region element and associated animate and set out-of-line animation elements. * In 13.3 (new), add new sub-section defining animation specific value expressions. * In 14.1, add new 'ttm:item' element to represent arbitrary named metadata information items. * In 14.1.1, extend content model of 'metadata' to permit the use of embedded content 'data' element children. * 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 E, add #animation-version-2, #bidi-version-2, #border, #profile-version-2, #region-timing, #ruby, #ruby-non-nested, #textAlign-justify, #textAlign-version-2, #textEmphasis, #textEmphasis-minimal, #textEmphasis-no-color, #textEmphasis-no-quoted-string, #textOrientation, #time-wall-clock, #unicodeBidi-isolate, and #validation feature designators. * In Appendix G, define only newly introduced TTML2 profiles. * In Appendix G, add #border and #textOrientation designators in standard profiles. * In Appendix J, add (normative) reference to RFC2396 (URI). * In Appendix J, add (normative) reference to Ruby Annotations REC. * In Appendix J, add (normative) reference to CSS Ruby Draft. * In Appendix J, move SVG1.1 reference from Appendix H and update to Second Edition. * In Appendix H, upgrade material on time expression semantics to normative, (previously in Appendix N of TTML1). Editorial Changes * In 1.1, update Figure 1 - System Model. * In 2.1, add acronym: "ISD". * In 2.2, add definitions: "anonymous profile", "audio defining context", "audio presentation context", "authoring viewport", "baseline profile", "chunked data embedding", "content profile", "data binding context", "data binding context for metadata", "data binding context for source", "data context context", "data element", "data resource", "default processor profile", "designated profile", "display aspect ratio", "display region target", "display target", "document temporal coordinate space", "dot pitch", "embedded content element", "embedded data resource", "enclosing document instance", "extension specification", "external data resource", "external data source", "feature specification", "font defining context", "font presentation context", "font selection process", "fragment identifier", "image defining context", "image presentation context", "implied inline region", "inline animation", "inline region", "intermediate synchronic document", "intermediate synchronic document sequence", "intermediate synchronic document sequence syntax", "nested embedded source", "nested profile", "nesting profile", "non-nested embedded source", "non-nesting profile", "out-of-line animation", "out-of-line region", "pixel aspect ratio", "presentation viewport", "profile", "profile designator", "profile fragment identifier", "profile specification", "related media object region target", "sourced data embedding", "storage aspect ratio", "top-level profile", "undesignated profile", "viewport", and "viewport target". * In 2.2, refine definition of "out-of-line region" to better account for default region implication. * In 2.3, add text clarifying meaning of expression '{any attribute not in default or any TT namespace}'. * In 2.3, add convention for deprecated syntactic features (using distinct background color). * In 5.*, renumber tables to use M-N format. * In 5.1, extend note under Table 5-1 to clarify meaning of unqualified attribute names. * In 6.*, subdivide section 6 into two top level sections that segregate profile and parameter matter. * In 6.*, renumber tables to use M-N format. * In 6.1.3, segregate the semantics of the 'value' attribute according to whether the profile is a processor or content profile. * In 6.1.5, segregate the semantics of the 'value' attribute according to whether the profile is a processor or content profile. * In 10.2, add note about the use of non-applicable style attributes. * In 10.2, renumber sub-sections to account for newly defined attributes. * In 10.4.4.4, rework [filter] step to explicitly enumerate element types not filtered. * In 11.3, insert "Inline Regions" as sub-section 9.3.2, renumbering following sub-sections. * In 12.2, reorder attributue sub-sections to be alphabetic. * In 12.3, permit metric component to be omitted from offset-time, in which case 's' (seconds) is implied. * In 14.1, reorder ttm:* attribute sub-sections to be alphabetic. * Reorder (and relabel) appendices to maintain normative appendices followed by non-normative appendices. * In Appendix I, add subsections describing the relationship of media time to document time. * In Appendix J, add reference to Japanese Language Requirements (JLREQ), used normatively for definition of named character classes. * In Appendix K, add (non-normative) reference to CSS Writing Modes Level 3. * In Appendix K, add (non-normative) reference to original Namespaces in XML REC (NSOriginal). * In Appendix K, add (non-normative) reference to SDP US. * In Appendix K, add (non-normative) reference to TTML1. * In Appendix K, update SMIL reference to SMIL3.0. * In Appendix M, add derivation of tt:animate and tt:animation elements. * In Appendix M, add derivation of tts:border and tts:textOrientation attributes. * Insert new informative Appendix P on security and privacy considerations. * Insert new informative Appendix Q with an example of HDR compositing. * Insert new informative Appendix T with syntax changes since TTML1. * Migrate to new W3C style sheets and table of content format. * Change convention for labeling and citing definitions to use "[lower case]" in definitions and hyperlinked "lower case" in citations. * Update SMIL section number references to track SMIL3.