diff --git a/spec/ttml2.html b/spec/ttml2.html index e124009a4..98d508aa3 100644 --- a/spec/ttml2.html +++ b/spec/ttml2.html @@ -338,9 +338,9 @@ border: 2px solid black; width: 100%; } - Last Modified: $Date: Sun Jun 18 14:31:27 2017 -0600 $
+ Last Modified: $Date: Thu Jun 29 13:46:29 2017 -0600 $

Timed Text Markup Language 2 (TTML2)

-

Editors' copy $Date: Sun Jun 18 14:31:27 2017 -0600 $ @@ @@@@ @@@@

This version:
+

Editors' copy $Date: Thu Jun 29 13:46:29 2017 -0600 $ @@ @@@@ @@@@

This version:
ttml2.html
Latest editor's draft:
https://w3c.github.io/ttml2/spec/ttml2.html
Latest version:
https://www.w3.org/TR/ttml2/
Latest recommendation:
https://www.w3.org/TR/ttml1/
Previous version:
https://www.w3.org/TR/2016/WD-ttml2-20161117/ @@ -359,7 +359,7 @@

Abstract

This document specifies the Timed Text <textstream> media element in a [SMIL 3.0] document.

Status of This Document

This document is an editor's copy that has no official standing.

+

Appendices

1 Introduction

Unless specified otherwise, this section and its sub-sections are non-normative.

The Timed Text Markup Language (TTML), Version 2, also referred to as TTML2, provides a standardized representation of a particular subset of textual information with which stylistic, layout, and timing semantics are associated by @@ -642,7 +642,7 @@

2.2 Terminology

effective processor profile in the absence of a declared or inferred processor profile, where this default processor profile is determined by the construct default processor profile -procedure.

[default profile]

To Be Defined

[default region]

A default out-of-line region that is implied in the absence of +procedure.

[default region]

A default out-of-line region that is implied in the absence of an explicitly specified out-of-line region element, i.e., when no region element is specified as a child of a layout element.

[designated profile]

A profile that is associated with a profile designator by @@ -704,7 +704,10 @@

2.2 Terminology

data element within a source element child, or it may reference another image element specified in a -image defining context, or it may do both.

[image resource]

A data resource that contains a raster image.

[inferred processor profile]

To Be Defined

[inline animation]

An animate or set element +image defining context, or it may do both.

[image resource]

A data resource that contains a raster image.

[inferred processor profile]

A processor profile determined by the +construct inferred processor profile procedure which may +serve as the effective processor profile used to perform +validation processing.

[inline animation]

An animate or set element that is defined inline as an immediate child of a content element or region element associated with the animation. There is a one-to-one relation between @@ -839,7 +842,9 @@

2.2 Terminology

[undesignated profile]

A profile that is not associated with a profile designator, and which is referred to implicitly in the context of the profile's definition. Also referred to as an anonymous profile.

[valid abstract document instance]

An abstract document instance which has been assessed for validity -and found to be valid as defined by 4 Document Types.

[validating content processor]

To Be Defined

[vertical axis]

An axis perpendicular to the plane of the horizon.

[width]

An absolute dimension on the horizontal axis.

[writing mode]

An enumeration collection of tokens, each of which designates a combination of the axis and direction of flow of +and found to be valid as defined by 4 Document Types.

[validating content processor]

A content processor which performs validation processing on a + TTML document instance prior to performing any other type of processing.

Note:

A validating content processor may have the sole function of validating (or verifying) a document instance, + or it may have multiple functions, the first of which is validating (or verifying) a document instance.

[vertical axis]

An axis perpendicular to the plane of the horizon.

[width]

An absolute dimension on the horizontal axis.

[writing mode]

An enumeration collection of tokens, each of which designates a combination of the axis and direction of flow of both inline and block oriented content, about which see 10.2.55 tts:writingMode.

2.3 Documentation Conventions

Within normative prose in this specification, the words may, should, and must are @@ -1109,7 +1114,7 @@

5.2.1 Introduction

Th attribute on the root tt element, (2) one or more ttp:profile elements of type processor, or (3) a combination of these two mechanisms. If not declared, a processor profile is inferred from a declared content profile or from a -default profile.

Note:

It is not a requirement on a conformant document instance that a processor profile be internally +default processor profile.

Note:

It is not a requirement on a conformant document instance that a processor profile be internally declared by use of a ttp:profile element or internally referenced by a ttp:processorProfiles attribute. More specifically, it is permitted that the document @@ -12288,7 +12293,7 @@

M Requirements (Non-Normative)

The Timed Tex

N Vocabulary Derivation (Non-Normative)

This appendix provides information about the derivation of TTML vocabulary, separately describing derivation of elements and attributes.

Issue (issue-ttml2-380):

Update vocabulary derivation tables in Appendix N.

Source: https://github.com/w3c/ttml2/issues/380

Add or update element and attribute vocabulary derivation information.

Resolution:

None recorded.

-

N.1 Element Derivation

The first column of Table M-1 – Elements +

N.1 Element Derivation

The first column of Table M-1 – Elements specifies a TTML element vocabulary item; the second column specifies the syntactic and/or semantic model on which the vocabulary item is based; the third column specifies the reference that defines @@ -12345,7 +12350,7 @@

N.1 Element Derivation

The first column of @version on the svg:svg element.

  • Conceptually derived from existing tt:layout element, which is a generic container for layout specifications, but for use in defining animation specifications that apply to targeted elements.

    • -

    N.2 Attribute Derivation

    The first column of Table M-2 – Attributes +

    N.2 Attribute Derivation

    The first column of Table M-2 – Attributes specifies a TTML attribute vocabulary item; the second column specifies the syntactic and/or semantic model on which the vocabulary item is based; the third column specifies the reference that defines @@ -12437,25 +12442,25 @@

    N.2 Attribute Derivation

    The first column of O QA Framework Compliance (Non-Normative)

    This appendix specifies the compliance of this specification with the requirements and guidelines defined by QA Framework Specifications Guidelines [QAF SG].

    -

    O.1 Requirements

    Table N-1 – QA Framework Requirements Checklist
    RequirementYESNON/ANotes
    Requirement 01: Include a conformance +

    O.1 Requirements

    Table N-1 – QA Framework Requirements Checklist
    RequirementYESNON/ANotes
    Requirement 01: Include a conformance clauseYES
    Requirement 02: Define the scope.YES
    Requirement 03: Identify who or what will implement the specification.YES
    Requirement 04: Make a list of normative references.YES
    Requirement 05: Define the terms used in the normative parts of the specification.YES
    Requirement 06: Create conformance labels for each part of the conformance model.YES
    Requirement 07: Use a consistent style for conformance requirements and explain how to distinguish them.YES
    Requirement 08: Indicate which conformance requirements are mandatory, which are recommended, and which are optional.YES
    Requirement 09: If the technology is subdivided, then indicate which subdivisions are mandatory for conformance.YES
    Requirement 10: If the technology is subdivided, then address subdivision constraints.YES
    Requirement 11: Address Extensibility.YES
    Requirement 12: Identify deprecated features.YES
    Requirement 13: Define how each class of product handles each deprecated feature.YES
    -

    O.2 Guidelines

    Table N-2 – QA Framework Guidelines Checklist
    GuidelineYESNON/ANotes
    Good Practice 01: Define the specification's conformance model in the conformance clause.YES
    Good Practice 02: Specify in the conformance clause how to distinguish normative from informative content.YES
    Good Practice 03: Provide the wording for conformance claims.YES
    Good Practice 04: Provide an Implementation Conformance Statement Pro Forma.NO
    Good Practice 05: Require an Implementation Conformance Statement as part of valid conformance claims.YES
    Good Practice 06: Provide examples, use cases, and graphics.YES
    Good Practice 07: Write sample code or tests.YES
    Good Practice 08: When imposing requirements by normative references, address conformance dependencies.YES1
    Good Practice 09: Define unfamiliar terms in-line and consolidate the definitions in a glossary section.YES
    Good Practice 10: Use terms already defined without changing their definition.YES2
    Good Practice 11: Use formal languages when possible.YES
    Good Practice 12: Write Test Assertions.NO3
    Good Practice 13: Create subdivisions of the technology when warranted.YES
    Good Practice 14: If the technology is profiled, define rules for creating new profiles.YES
    Good Practice 15:Use optional features as warranted.YES
    Good Practice 16: Clearly identify optional features.YES
    Good Practice 17: Indicate any limitations or constraints on optional features.YES
    Good Practice 18: If extensibility is allowed, define an extension mechanism.YES
    Good Practice 19: Warn extension creators to create extensions that do not interfere with conformance.YES
    Good Practice 20: Define error-handling for unknown extensions.YES4
    Good Practice 21: Explain how to avoid using a deprecated feature.YES
    Good Practice 22: Identify obsolete features.N/A5
    Good Practice 23: Define an error handling mechanism.YES

    Note:

    1. When making normative references to external specifications, +

      O.2 Guidelines

      Table N-2 – QA Framework Guidelines Checklist
      GuidelineYESNON/ANotes
      Good Practice 01: Define the specification's conformance model in the conformance clause.YES
      Good Practice 02: Specify in the conformance clause how to distinguish normative from informative content.YES
      Good Practice 03: Provide the wording for conformance claims.YES
      Good Practice 04: Provide an Implementation Conformance Statement Pro Forma.NO
      Good Practice 05: Require an Implementation Conformance Statement as part of valid conformance claims.YES
      Good Practice 06: Provide examples, use cases, and graphics.YES
      Good Practice 07: Write sample code or tests.YES
      Good Practice 08: When imposing requirements by normative references, address conformance dependencies.YES1
      Good Practice 09: Define unfamiliar terms in-line and consolidate the definitions in a glossary section.YES
      Good Practice 10: Use terms already defined without changing their definition.YES2
      Good Practice 11: Use formal languages when possible.YES
      Good Practice 12: Write Test Assertions.NO3
      Good Practice 13: Create subdivisions of the technology when warranted.YES
      Good Practice 14: If the technology is profiled, define rules for creating new profiles.YES
      Good Practice 15:Use optional features as warranted.YES
      Good Practice 16: Clearly identify optional features.YES
      Good Practice 17: Indicate any limitations or constraints on optional features.YES
      Good Practice 18: If extensibility is allowed, define an extension mechanism.YES
      Good Practice 19: Warn extension creators to create extensions that do not interfere with conformance.YES
      Good Practice 20: Define error-handling for unknown extensions.YES4
      Good Practice 21: Explain how to avoid using a deprecated feature.YES
      Good Practice 22: Identify obsolete features.N/A5
      Good Practice 23: Define an error handling mechanism.YES

      Note:

      1. When making normative references to external specifications, specific clauses or sections are cited.

      2. See also N Vocabulary Derivation.

      3. Test assertions and test suites will be provided prior to entering Proposed Recommendation (PR) phase.

      4. See criterion #3 in 3.2 Processor Conformance and definition of TTML Abstract Document Instance.

      5. No feature is obsoleted by this version of this specification.

    P Security and Privacy Considerations (Non-Normative)

    -

    P.1 Use of XML as Concrete Encoding

    When [XML 1.0] is used as the concrete encoding of a +

    P.1 Use of XML as Concrete Encoding

    When [XML 1.0] is used as the concrete encoding of a timed text document instance, the security considerations specified by [XML Media Types] and [XML Guidelines] apply.

    Note:

    XML entities are not included in the reduced xml infoset of a timed text document instance; nevertheless, implementations are encouraged to provide protection against recursive entity expansion or prevent entity expansion altogether in a TTML processor.

    -

    P.2 Document Processing

    A timed text document instance is intended to +

    P.2 Document Processing

    A timed text document instance is intended to be processed in some manner by a content processor. Although this specification defines the meaning of conformant processing of a timed text document instance by such a processor, the actual implementation of that processor is outside the scope of this specification.

    -

    P.3 Resource Fetching

    This specification defines mechanism that allow a timed text document instance +

    P.3 Resource Fetching

    This specification defines mechanism that allow a timed text document instance to make reference to external resources, including audio, font, image, and untyped (generic) data resources. The fetching of such resources as well as fetching the concrete representation of a @@ -12464,24 +12469,24 @@

    P.3 Resource Fetching

    This specification defines any controls designed to allow or restrict access to such resources are also outside the scope of this specification.

    If the fetching of such resources is prevented by the content processor, then the entire document or portions of the document may not be processed as intended, and, therefore, some or all of a document's content may not be available for presentation processing.

    -

    P.4 Caching of Resources or Processing State

    The processing of a timed text document instance defined herein +

    P.4 Caching of Resources or Processing State

    The processing of a timed text document instance defined herein does not specify or depend in any manner on the content processor caching or storing any resource or processing state.

    -

    P.5 No Script Language

    This specification does not include or make reference to the processing of any script language or executable code.

    -

    P.6 No External Style Sheets

    This specification does not include or make reference to the processing of any external style sheet or style specification; rather, +

    P.5 No Script Language

    This specification does not include or make reference to the processing of any script language or executable code.

    +

    P.6 No External Style Sheets

    This specification does not include or make reference to the processing of any external style sheet or style specification; rather, all style information is directly integrated into the TTML document syntax, and is processed in terms of the reduced xml infoset respresentation of this syntax.

    -

    P.7 Access to Processing State

    A mechanism is defined herein to allow the conditional processing of content where conditional expressions +

    P.7 Access to Processing State

    A mechanism is defined herein to allow the conditional processing of content where conditional expressions may take into account certain processing state, including a user language preference, a related media language, whether forced captions are enabled or not, and whether a media query expression is satisfied or not. However, direct access to this state is not provided to TTML content; rather the content processor accesses this state and make a binary (yes or no) determination of whether a condition is satisfied or not.

    -

    P.8 Hyperlinking Mechanisms

    A mechanism is defined herein, based on [XLink 1.1], that permits an author to associate content with +

    P.8 Hyperlinking Mechanisms

    A mechanism is defined herein, based on [XLink 1.1], that permits an author to associate content with external documents. Whether or not semantic support is provided for this mechanism by the content processor is a determination made outside the scope of this specification. Furthermore, the semantics of link activation, if supported, is similarly outside the scope of this specification.

    Q High Dynamic Range Compositing (Non-Normative)

    This appendix illustrates how sRGB pixels can be composited onto high dynamic range (HDR) pixels.

    -

    Q.1 Perceptual Quantizer

    +

    Q.1 Perceptual Quantizer

    The following illustrates the use of tts:luminanceGain to composite sRGB pixels onto HDR pixels that conform to the system colorimetry specified in [ITU BT.2100-1] using perceptual quantizer (PQ) EOTF and full-range quantization.

    1. @@ -12535,7 +12540,7 @@

      Q.1 Perceptual Quantizer

      where clamp(x) = {x, if x ∈ [0, 1023]} or {1023, if x > 1023}

    -

    Q.2 Hybrid Log-Gamma HDR

    The following illustrates compositing of sRGB pixels onto Hybrid Log-Gamma (HLG) HDR pixels. +

    Q.2 Hybrid Log-Gamma HDR

    The following illustrates compositing of sRGB pixels onto Hybrid Log-Gamma (HLG) HDR pixels.

    1. Let (r, g, b) be a full-range 8-bit sRGB pixel with opacity of A between 0 and 255.

    2. Let (R,G,B) and (Rc,Gc,Bc) be narrow-range 10-bit pixels in the system colorimetry specified in [ITU BT.2100-1] using HLG EOTF and narrow-range quantization. Subscript c denoting the video signal post-compositing.

    3. Let (X,Y,Z) be pixels in the system colorimetry specified in the CIE 1931 XYZ colour space [XYZ] .

    4. Invert the 8-bit full-range quantization:

      (r, g, b)/255 → (r, g, b)

      A/255 → A

    5. Linearize using the sRGB EOTF:

      (r2.2,g2.2,b2.2) → (r,g,b)

    6. Convert from sRGB color space to [ITU BT.2100-1] color space:

      [(0.4124, 0.3576, 0.1805), (0.2126, 0.7152, 0.0722), (0.0193,0.1192,0.9505)]•(r,g,b)→(X,Y,Z)

      [(1.7167, −0.3557, −0.2534), (−0.6667, 1.6165, 0.0158), (0.0176,−0.04277,0.9421)]•(X,Y,Z)→(r,g,b)

    7. Apply simplified inverse HLG OOTF:

      ((0.265r),(0.265g),(0.265b)) → (r,g,b)

    8. Apply HLG OETF specified in [ITU BT.2100-1]:

      (HLG(r),HLG(g),HLG(b)) → (r,g,b)

      where HLG(x) = (3x)0.5 if 0 ≤ x ≤ 1/12 or HLG(x) = a•ln(12x−b)+c if x > 1/12 and a = 0.17883277 and b = 1−4a and c = 0.5−a•ln(4a)5b

    9. Apply 10-bit narrow-range quantization:

      (Q(r),Q(g),Q(b)) → (r,g,b)

      where Q(x) = floor((940 − 64) • x + 64.5)

    10. Composite foreground graphic (r,g,b) over background video (R,G,B) with opacity A to yield (Rc,Gc,Bc):

      ((A•r+(1−A)R),(A•g+(1−A)G),(A•b+(1−A)B)) → (Rc,Gc,Bc)

    11. Clamp output to 10-bit signal range:

      (clamp(Rc),clamp(Gc),clamp(Bc)) → (Rc,Gc,Bc)

      where clamp(x) = x if 0 ≤ x ≤ 1023 or 0 if x < 0 or 1023 if x > 1023

    Note:

    The above algorithm does not use the tts:luminanceGain attribute since no absolute gain level is needed for HLG HDR. Rather, this algorithm maps peak sRGB white to "graphics white" in HLG which is defined as 75% of the narrow range signal defined in [ITU BT.2100-1].

    @@ -12725,14 +12730,14 @@

    T.3 Customisation by break

    U Changes to Vocabulary from TTML1 (Non-Normative)

    This section provides a high level summary of vocabulary changes between Timed Text Markup Language (TTML) Version 1 (TTML1) and Version 2 (TTML2). It is not the intent of this summary to be exhaustive. For more details about changes, see Changes from TTML1 (2nd Ed.) to TTML2 Working Draft (Latest Revision).

    -

    U.1 New Element Vocabulary

    New element vocabulary was added in the following sections of this specification as further described below:

    -

    U.1.1 Animation Vocabulary

    The following elements were added in order to enhance support for animation functionality:

    tt:animate

    Support continuous animation within and across one or more temporally contiguous active time intervals.

    tt:animation

    Support grouping of out-of-line animation directives in header matter.

    -

    U.1.2 Embedded Content Vocabulary

    The following elements were added in order to support embedded content and content references:

    tt:audio

    Support use of built-in, embedded, and external audio resources.

    tt:chunk

    Support use of chunking when embedding audio, data, font, and image resources, +

    U.1 New Element Vocabulary

    New element vocabulary was added in the following sections of this specification as further described below:

    +

    U.1.1 Animation Vocabulary

    The following elements were added in order to enhance support for animation functionality:

    tt:animate

    Support continuous animation within and across one or more temporally contiguous active time intervals.

    tt:animation

    Support grouping of out-of-line animation directives in header matter.

    +

    U.1.2 Embedded Content Vocabulary

    The following elements were added in order to support embedded content and content references:

    tt:audio

    Support use of built-in, embedded, and external audio resources.

    tt:chunk

    Support use of chunking when embedding audio, data, font, and image resources, where chunking refers to the subdivision of resource content into contiguous data segments (chunks).

    tt:data

    Support use of built-in, embedded, and external data resources.

    tt:font

    Support use of built-in, embedded, and external font resources.

    tt:image

    Support use of built-in, embedded, and external image resources.

    tt:resources

    Support grouping of sharable embedded content and content references in header matter.

    tt:source

    Support alternative sources of embedded content and content references.

    -

    U.1.3 Metadata Vocabulary

    The following element was added in order to expand metadata functionality:

    ttm:item

    Support extensible collection of named metadata items.

    Note:

    This feature is motivated by the desire to avoid defining additional new vocabulary for metadata items that +

    U.1.3 Metadata Vocabulary

    The following element was added in order to expand metadata functionality:

    ttm:item

    Support extensible collection of named metadata items.

    Note:

    This feature is motivated by the desire to avoid defining additional new vocabulary for metadata items that consist of a name and a value, where a generic, named metadata item element can serve future needs for defining an unbounded collection of such items.

    -

    U.1.4 Styling Vocabulary

    The following element was added in order to expand styling functionality:

    tt:initial

    Support author specified initial values for style properties.

    Note:

    This feature is motivated by multiple requirements, including +

    U.1.4 Styling Vocabulary

    The following element was added in order to expand styling functionality:

    tt:initial

    Support author specified initial values for style properties.

    Note:

    This feature is motivated by multiple requirements, including (1) that it is desirable to be able to specify a fixed, determinate value for certain initial values for inherited style properties that this specification defines as implementation dependent, e.g., the initial value of tts:color, and @@ -12740,12 +12745,12 @@

    U.1.4 Styling Vocabulary

    The following element w properties rather than be forced to explicitly specify a style value in each case, e.g., an initial value for tts:showBackground of whenActive may be preferred instead of the default initial value of always.

    -

    U.2 New Attribute Vocabulary

    New attribute vocabulary was added in the following sections of this specification as further described below:

    -

    U.2.1 Animation Attributes

    The following attribute was added in order to expand animation functionality:

    -

    U.2.2 Content Attributes

    The following attributes were added in order to expand content functionality:

    -

    U.2.3 Parameter Attributes

    The following attributes were added in order to expand parameter functionality:

    -

    U.2.4 Profile Attributes

    The following attributes were added in order to expand profiling functionality:

    -

    U.2.5 Styling Attributes

    The following attributes were added in order to expand styling functionality:

    +

    U.2 New Attribute Vocabulary

    New attribute vocabulary was added in the following sections of this specification as further described below:

    +

    U.2.1 Animation Attributes

    The following attribute was added in order to expand animation functionality:

    +

    U.2.2 Content Attributes

    The following attributes were added in order to expand content functionality:

    +

    U.2.3 Parameter Attributes

    The following attributes were added in order to expand parameter functionality:

    +

    U.2.4 Profile Attributes

    The following attributes were added in order to expand profiling functionality:

    +

    U.2.5 Styling Attributes

    The following attributes were added in order to expand styling functionality:

    V Acknowledgments (Non-Normative)

    The editor acknowledges the current and former members of the Timed Text Working Group, the members of other W3C Working Groups, and industry experts in other forums who have contributed directly or indirectly to the