17. SMIL 3.0 Language Profile

This section is normative.

The SMIL 3.0 Language profile describes the SMIL 3.0 modules that are included in the SMIL 3.0 Language and details how these modules are integrated. It contains support for all of the major SMIL 3.0 features including animation, content control, layout, linking, media object, meta-information, structure, timing and transition effects. It is designed for Web clients that support direct playback from SMIL 3.0 markup.

This section is normative.

In the text in this profile specification, the term Language Profile will be considered to refer exclusively to the SMIL 3.0 Language profile as defined in this document.

17.4.1 SMIL 3.0 Language Profile Conformance

The definition of conformance for a SMIL 3.0 profile is given in the Definitions section of the SMIL 3.0 Scalability Framework. Based on these definitions, the Language profile is a Strict Host-Language Conformant SMIL 3.0 Profile.

Within the referenced sections of the Scalability Framework, the following definitions should be used:

1. The profile identification string for the Language profile is: http://www.w3.org/2008/SMIL30/Language.
2. Documents written for the Language profile must declare the default SMIL namespace with the xmlns attribute on the smil root element. For SMIL 3.0, this is:

   xmlns="http://www.w3.org/ns/SMIL"

3. The SMIL 3.0 Language profile DOCTYPE is:

   <!DOCTYPE smil PUBLIC "-//W3C//DTD SMIL 3.0 Language//EN"
   "http://www.w3.org/2008/SMIL30/SMIL30Language.dtd">

   If a document contains this declaration, it must be a valid XML document. Note that this implies that extensions to the syntax defined in the DTD (or in the corresponding XML or RelaxNG schemas) are not allowed. If the document is invalid, the user agent should issue an error.
4. The identification string for the non-normative DTD used for integration of errata is:

   http://www.w3.org/2008/SMIL30/informative-DTD/SMIL30Language.dtd

5. Documents written for the Language Profile must declare (explicitly or implicitly via the DTD) the following values for the version and baseProfile attributes:

   version="3.0" baseProfile="Language"

   As a consequence of the two requirements above, the effective root element declaration for a Language profile document must be:

   <smil xmlns="http://www.w3.org/ns/SMIL" version="3.0" baseProfile="Language">
        ...
   </smil> 

   The root element may be extended as required with additional atttributes.

This version of SMIL provides a definition of strict host-language conformant SMIL 3.0 documents, which are restricted to tags and attributes from the SMIL 3.0 namespace. The Section "Extending/Restricting a SMIL 3.0 Profile" provides information on using the SMIL 3.0 Language profile with other namespaces, for instance, on including new tags within SMIL 3.0 documents.

Language designers and implementors wishing to extend the Language profile must consider the implications of the use of namespace extension syntax. Please consult the section on Scalable Profiles for restrictions and recommendations for best practice when extending SMIL.

17.4.2 SMIL 3.0 Language Profile User Agent Conformance

The definition of user agent conformance for SMIL 3.0 Language profile documents is given in the Conforming SMIL 3.0 User Agents section of the SMIL 3.0 Scalability Framework. Conforming Language profile user agents must adhere completely to this section.

17.4.3 The SMIL 3.0 Language Profile

The SMIL 3.0 Language profile supports the structured-timeline-centric multimedia features found in the SMIL 3.0 modules. It uses only modules from the SMIL 3.0 recommendation. This Language profile includes the following SMIL 3.0 modules:

1. Structure functionality
   1. Structure Module
   2. Identity Module
2. Media functionality
   1. BasicMedia Module
   2. BrushMedia Module
   3. MediaAccessibility Module
   4. MediaClipMarkers Module
   5. MediaClipping Module
   6. MediaDescription Module
   7. MediaOpacity Module
   8. MediaPanZoom Module
   9. MediaParam Module
   10. MediaRenderAttributes Module
3. Timing functionality
   1. AccessKeyTiming Module
   2. BasicExclTimeContainers Module
   3. BasicInlineTiming Module
   4. BasicPriorityClassContainers Module
   5. BasicTimeContainers Module
   6. EventTiming Module
   7. FillDefault Module
   8. MediaMarkerTiming Module
   9. MinMaxTiming Module
   10. MultiArcTiming Module
   11. RepeatTiming Module
   12. RepeatValueTiming Module
   13. RestartDefault Module
   14. RestartTiming Module
   15. SyncbaseTiming Module
   16. SyncBehaviorDefault Module
   17. SyncBehavior Module
   18. WallclockTiming Module
4. Content Control functionality
   1. BasicContentControl Module
   2. CustomTestAttributes Module
   3. PrefetchControl Module
   4. RequiredContentControl Module
   5. SkipContentControl Module
5. Layout functionality
   1. AlignmentLayout Module
   2. AudioLayout Module
   3. BackgroundTilingLayout Module
   4. BasicLayout Module
   5. MultiWindowLayout Module
   6. OverrideLayout Module
   7. StructureLayout Module
   8. SubRegionLayout Module
6. smilText functionality
   1. BasicText Module
   2. TextMotion Module
   3. TextStyling Module
7. Linking functionality
   1. BasicLinking Module
   2. LinkingAttributes Module
   3. ObjectLinking Module
8. Metainformation functionality
   1. Metainformation Module
9. Transition Effects functionality
   1. BasicTransitions Module
   2. FullScreenTransitions Module
   3. TransitionModifiers Module
10. Animation functionality
    1. BasicAnimation Module
11. State functionality
    1. StateInterpolation Module
    2. StateSubmission Module
    3. StateTest Module
    4. UserState Module

The collection names contained in the following table define the SMIL 3.0 Language profile vocabulary.

In the following sections, we define the set of elements and attributes used in each of the modules included in the SMIL 3.0 Language profile. The content model for each element is described. The content model of an element is a description of elements which may appear as its direct children. The special content model "EMPTY" means that a given element may not have children.

The xml:id and id attributes are used to assign a unique XML identifier to every element in a SMIL document. The xml:id and id attributes are equivalent and must not both be used on an element. The xml:id should be used in preference to the id attribute. When the document uses the SMIL 3.0 Language Profile DOCTYPE, only xml:id must be used.

The attributes in the collection Core are defined for all the elements of the SMIL 3.0 Language profile.

In this document, equivalent but deprecated attributes and elements are in parentheses.

17.4.4 Structure Modules

The Structure Module provides a framework for structuring a SMIL document. The Structure Module defines semantics for the smil, head and body elements. The SMIL 3.0 Language profile includes the Structure functionality of the Structure module.

The Identity Module provides attributes to identify the SMIL version and profile used in a SMIL document. The Identity Module defines semantics for the version and baseProfile attributes. The SMIL 3.0 Language profile includes the functionality of the Identity Module. The SMIL 3.0 Language Profile DTD provides default values for version and baseProfile.

In the SMIL 3.0 Language profile, the Structure elements may have the following attributes and content model :

The attribute xmlns must be present on the element smil and it must have the value 'http://www.w3.org/ns/SMIL'.

The body element acts as the root element to span the timing tree. The body element has the behavior of a seq element. Timing on the body element is supported. The syncbase of the body element is the application begin time, which is implementation dependent, as is the application end time. Note that the effect of fill on the body element is between the end of the presentation and the application end time, and therefore the effect of fill is implementation dependent.

17.4.5 Media Object Modules

The Media Object Modules provide a framework for declaring media. The Media Object Modules define semantics for the ref, animation, audio, img, text, textstream, video and brush elements. The SMIL 3.0 Language profile includes the Media functionality of the BasicMedia, BrushMedia, MediaAccessibility, MediaClipping, MediaClipMarkers, MediaDescription, MediaOpacity, MediaPanZoom, MediaParam and MediaRenderAttributes modules.

In the SMIL 3.0 Language profile, media elements may have the following attributes and content model:

The attribute collections MediaDescriptionAttributes and MediaOpacityAttributes are defined as follows:

This profile adds the ref, animation, audio, img, text, textstream, video and brush elements to the content model of the par, seq, excl and priorityClass elements of the Timing and Synchronization Modules. It also adds these elements to the content model of the body element of the Structure Module, to the content model of the a element of the Linking Modules and to the content model of the switch element of the Content Control Modules.

SMIL 1.0 only allowed anchor as a child element of a media element. In addition to anchor, the following elements are allowed in SMIL 3.0 as children of a SMIL media object: area, param, animate, set, animateColor, animateMotion, meta, metadata (note that the a element is not included). The switch element is allowed, with the restriction that in this case the content of the switch may only be from the same set of elements.

Media Object Integration Requirements

The MediaRenderAttributes Module defines the erase attribute, and defers definition of the "display area" to the language profile. "Display area" for the purposes of the SMIL 3.0 Language corresponds to a SMIL BasicLayout region. The effects of erase="never" apply after the active duration of the media object and any fill period (defined by SMIL Timing and Synchronization), and only until other media plays to the region targeted by the media object, or until the same media object restarts.

17.4.6 Timing and Synchronization Modules

The Timing and Synchronization Modules provide a framework for describing timing structure, timing control properties and temporal relationships between elements. The Timing and Synchronization Modules define semantics for par, seq, excl and priorityClass elements. In addition, these modules define semantics for attributes including begin, dur, end, fill, fillDefault, repeat (deprecated), repeatCount, repeatDur, restart, restartDefault, syncBehavior, syncBehaviorDefault, syncTolerance, syncToleranceDefault. The SMIL 3.0 Language profile includes the Timing functionality of the AccessKeyTiming Module, BasicInlineTiming Module, BasicTimeContainers Module, BasicExclTimeContaine Module, BasicPriorityClassContainers Module, EventTiming Module, FillDefault Module, MediaMarkerTiming Module, MinMaxTiming Module, MultiArcTiming Module, RepeatTiming Module, RepeatValueTiming Module, RestartDefault Module, RestartTiming Module, SyncbaseTiming Module, SyncBehavior Module, SyncBehaviorDefault Module, WallclockTiming Module modules.

In the SMIL 3.0 Language profile, Timing and Synchronization elements may have the following attributes and content model :

The Attribute collections Timing and BasicTiming are defined as follows:

This profile adds the par, seq and excl elements to the content model of the body element of the Structure Module, to the content model of the a element of the Linking Modules and to the content model of the switch element of the Content Control Modules.

Elements of the Media Object Modules, elements of the Animation Module, elements of the State Modules and the smilText element of the smilText Modules have the attributes describing timing and properties of contents.

Supported Event Symbols

The SMIL 3.0 Language profile specifies which types of events may be used as part of the begin and end attribute values. The supported events are described as Event-symbols according to the syntax introduced in the SMIL Timing and Synchronization module.

The supported event symbols in the SMIL 3.0 Language profile are:

Event semantics

focusInEvent:

Raised when a media element gets the keyboard focus in its rendering space, i.e., when it becomes the media element to which all subsequent keystroke-event information is passed. Once an element has the keyboard focus, it continues to have it until a user action or DOM method call either removes the focus from it or gives the focus to another media element, or until its rendering space is removed. Only one media element may have the focus at any particular time. The focusInEvent is delivered to media elements only, and does not bubble.

focusOutEvent:

Raised when a media element loses the keyboard focus from its rendering space, i.e., when it stops being the media element to which all subsequent keystroke-event information is passed. The focusOutEvent is delivered to media elements only, and does not bubble.

activateEvent:

Raised when a media element is activated by user input such as by a mouse click within its visible rendering space or by specific keystrokes when the element has the keyboard focus. The activateEvent is delivered to media elements only, and does not bubble.

beginEvent:

Raised when the element actually begins playback of its active duration. If an element does not ever begin playing, this event is never raised. If an element has a repeat count, beginEvent only is raised at the beginning of the first iteration. The beginEvent is delivered to elements which support timing, such as media elements and time containers, and does not bubble.

endEvent:

Raised when an element actually ends playback; this is when its active duration is reached or whenever a playing element is stopped.

This example is informative.

In the following example,

<ref xml:id="x" end="30s" src="15s.mpg" />
<ref xml:id="y" end="10s" src="20s.mpg" />
<ref xml:id="z" repeatCount="4" src="5s.mpg" />

x.endEvent occurs at roughly 30s when the active duration is reached, y.endEvent occurs at roughly 10s when the playback of the continuous media is ended early by the active duration being reached, and z.endEvent occurs at roughly 20s when the fourth and final repeat has completed, thus reaching the end of its active duration.

The endEvent is delivered to elements which support timing, such as media elements and time containers, and does not bubble.

repeatEvent:

Raised when the second and subsequent iterations of a repeated element begin playback. An element that has no repeatDur, repeatCount, or repeat attribute but that plays two or more times due to multiple begin times will not raise a repeatEvent when it restarts. Also, children of a time container that repeats will not raise their own repeatEvents when their parent repeats and they begin playing again. The repeatEvent is delivered to elements which support timing, such as media elements and time containers, and does not bubble.

inBoundsEvent:

Raised when one of the following happens:

• by any input from the mouse or other input device that brings the mouse cursor from outside to within the bounds of a media element's rendering space, regardless of what part, if any, of that rendering space is visible at the time, i.e., z-order is not a factor.
• by any other action that moves the "cursor" or "pointer", as defined by the implementation, from outside to within the bounds of a media element's rendering space, regardless of what part, if any, of that rendering space is visible at the time, i.e., z-order is not a factor. An implementation may decide, for instance, to raise an inBoundsEvent on an element whenever it gets the focus, including when keystrokes give it the focus.

A media element's bounds are restrained by the bounds of the region in which it is contained., i.e., a media element's bounds do not extend beyond its region's bounds. The inBoundsEvent is delivered to media elements only, and does not bubble.

Note that, unlike with keyboard focus which may only be active on one object at a time, the state of being within an object's bounds may be true for multiple objects simultaneously. For instance, if one object is on top of another and the cursor is placed on top of both objects, both would have raised an inBoundsEvent more recently than the raising of any respective outOfBoundsEvent.

outOfBoundsEvent:

Raised when one of the following happens:

• by any input from the mouse or other input device that brings the mouse cursor from within to outside the bounds of a media element's rendering space, regardless of what part, if any, of that rendering space is visible at the time,
• by any other action that moves the "cursor" or "pointer", as defined by the implementation, from within to outside the bounds of a media element's rendering space, regardless of what part, if any, of that rendering space is visible at the time.

A media element's bounds are restrained by its region's bounds, i.e., a media element's bounds do not extend beyond its region's bounds. The outOfBoundsEvent is delivered to media elements only, and does not bubble.

topLayoutCloseEvent:

Raised when a topLayout closes for any reason. This event is delivered to that topLayout. If a topLayout reopens when additional media becomes active in its region(s), this event will be raised again if and when the topLayout closes again, and will be raised every subsequent time it closes. This event is delivered to topLayout elements only and does not bubble.

topLayoutOpenEvent:

Raised when a topLayout window opens. This event is delivered to that topLayout. If a topLayout closes and then reopens when additional media becomes active in its region(s), this event will be raised again, and will be raised every subsequent time it reopens. This event is delivered to topLayout elements only and does not bubble.

stateChange(ref):

Raised by the state element. The parameter is a reference to an item in the data model. Whenever any of the referenced data model item is changed, this event is raised.

contentControlChange(attrname):

Raised by the root of the SMIL document when the named Content Control test values has changed. It does not bubble. The list of allowed values for attrname is taken from the Content Control Module attribute names. The parameterless contentControlChange event is raised as well.

contentControlChange:

Raised by the root of the SMIL document when any Content Control test value has changed. It does not bubble.

Order of raising of simultaneous events:

There will be cases where events occur simultaneously. To ensure that each SMIL 3.0 Language implementation handles them in the same order, the following order must be used to resolve ties:

1. InBoundsEvent
2. focusInEvent (should follow 1)
3. OutOfBoundsEvent
4. activateEvent (should follow 2)
5. focusOutEvent (should follow 3)
6. endEvent
7. beginEvent (must follow 6)
8. repeatEvent
9. topLayoutCloseEvent
10. topLayoutOpenEvent (must follow 9)
11. stateChange
12. contentControlChange(param)
13. contentControlChange

Events are listed in order of precedence, e.g., if event #6 in this list occurs at the same time as event #7, then #6 must be raised prior to #7.

The InBoundsEvent, focusInEvent, OutOfBoundsEvent, activateEvent and focusOutEvent events do not bubble and are delivered to the target media element.

The beginEvent, endEvent and repeatEvent events do not bubble and are delivered to the timed element on which the event occurs.

The topLayoutOpenEvent and topLayoutCloseEvent events do not bubble and are delivered to the topLayout element on which the event occurs.

Extending the set of supported events

The SMIL 3.0 Language profile supports an extensible set of events. In order to resolve possible name conflicts with the events that are supported in this profile qualified event names are supported. Namespace prefixes are used to qualify the event names. As a result, the colon is reserved in begin and end attributes for qualifying event names.

<smil ... xmlns:example="http://www.example.com">
   <img xml:id="foo" .../> 
   <audio begin="foo.example:focusInEvent".../>
    ... 
</smil>

Integration definitions

A SMIL document's begin time is defined as the moment a user agent begins the timeline for the overall document. A SMIL document's end time is defined as equal to the end time of the body element.

17.4.7 Content Control Modules

The Content Control Modules provide a framework for selecting content based on a set of test attributes. The Content Control Modules define semantics for the switch, prefetch, customAttributes and customTest elements. The SMIL 3.0 Language profile includes the Content Control functionality of the BasicContentControl, CustomTestAttributes, PrefetchControl, RequiredContentControl and SkipContentControl modules.

In the SMIL 3.0 Language profile, Content Control elements may have the following attributes and content model :

This profile adds the switch element to the content model of the par, seq and excl elements of the Timing and Synchronization Modules, the content model of the body and the head elements of the Structure Module, the content model of the a element of the Linking Modules, and the content model of the ref, animation, audio, img, text, textstream, video and brush elements of the Media Object Modules. The profile adds the customAttributes element to the content model of the head element and the customTest element to the content model of the customAttributes element.

The Content Control functionality is used to define the Attribute set "Test":

The collection of Attributes Test is added to all the elements defined in the SMIL 3.0 Language profile, except body, br, clear, customAttributes, customTest, div, head, meta, metadata, p, span, state, submission, tev and textStyling. A SMIL 3.0 user agent must support all of the values for the systemOperatingSystem and systemCPU attributes listed in the Content Control Modules. In addition, the user agent should accept namespaced values as future extensions, and not declare a syntax error. The user agent should return false for unrecognized values of the systemOperatingSystem and systemCPU attributes.

17.4.8 Layout Modules

The Layout Modules provide a framework for spatial layout of visual components. The Layout Modules define semantics for the region, root-layout, topLayout, layout and the regPoint elements. The SMIL 3.0 Language profile includes the Layout functionality of the AlignmentLayout Module, AudioLayout Module, BackgroundTilingLayout Module, BasicLayout Module, MultiWindowLayout Module, OverrideLayout Module, StructureLayoutModule, SubRegionLayout Module modules.

In the SMIL 3.0 Language profile, Layout elements may have the following attributes and content model :

The "background-color" attribute of SMIL1.0 is deprecated in favor of "backgroundColor", but both are supported.

The attribute collection SubregionAttributes is defined as follows:

This profile adds the layout element to the content model of the head element of the Structure Module. It also adds this element to the content model of the switch element of the Content Control Modules, when the switch element is a child of the head element.

17.4.9 smilText Modules

The smilText Modules provide a light-weight method of adding in-line text to a SMIL presentation. The smilText Modules define semantics for the smilText, tev, clear, br, span, p, div, textStyle, textStyling elements and their attributes. The SMIL 3.0 Language profile includes the smilText functionality of the BasicText, TextStyling and TextMotion modules.

In the SMIL 3.0 Language profile, SMILtext elements may have the following attributes and content model:

This profile adds the smilText element to the content model of the par, seq, excl and priorityClass elements of the Timing and Synchronization Modules. It also adds the elements to the content model of the body element of the Structure Module, to the content model of the a element of the Linking Modules and to the content model of the switch element of the Content Control Modules.

The SMILtext functionality is used to define the Attribute set "TextAttributes":

17.4.10 Linking Modules

The Linking Modules provide a framework for relating documents to content, documents and document fragments. The Linking Modules define semantics for the a and area (anchor) elements. They define also the semantics of a set of attributes defined for these elements. The SMIL 3.0 Language profile includes the Linking functionality of the BasicLinking, LinkingAttributes and ObjectLinking modules.

Both the a and area elements have an href attribute, whose value must be a valid URI.

Support for URIs with XPointer fragment identifier syntax is not required.

In the SMIL 3.0 Language profile, Linking elements may have the following attributes and content model :

This profile adds the a element to the content model of the par, seq and excl elements of the Timing and Synchronization Modules. It also adds the elements to the content model of the body element of the Structure Module and to the content model of the switch element of the Content Control Modules.

In the SMIL 3.0 language profile, a value of onLoad set on the attribute actuate indicates that the link is automatically traversed when the linking element becomes active. For linking elements containing SMIL timing, this is when the active duration of the linking element begins.

The attribute tabindex specifies the position of the element in the tabbing order at a particular instant for the current document. The tabbing order defines the order in which elements will receive focus when navigated by the user via an input device such as a keyboard. At any particular point in time, only active elements are taken into account for the tabbing order; inactive elements are ignored.

When a media object element has a tabindex attribute and becomes active, then its ordered tab index is inserted in the SMIL tab index at the location specified by the media object's tabindex attribute value. This assumes that the media object itself has tab indices, such as embedded HTML with tabindex attributes. This enables all link starting points in a SMIL presentation to have a place on the ordered list to be tab-keyed through, including those in embedded presentations.

For SMIL 1.0 backward compatibility, the anchor element is available but deprecated in favor of area. The anchor element supports the same attributes as area, both the new SMIL 3.0 attributes and the SMIL 1.0 attributes as defined in [SMIL10].

SMIL 1.0 backward compatibility: The show attribute value pause is deprecated in favor of setting the show attribute to new and the sourcePlaystate attribute to pause.

17.4.11 Metainformation Module

The Metainformation Module provides a framework for describing a document, either to inform the human user or to assist in automation. The Metainformation Module defines semantics for the meta and metadata elements. The SMIL 3.0 Language profile includes the Metainformation functionality of the Metainformation module.

In the SMIL 3.0 Language profile, Metainformation elements may have the following attributes and content model :

This profile adds the meta and metadata elements to the content model of all elements except meta, metadata and state.

The content model of metadata is empty. Profiles that extend the SMIL 3.0 Language profile may define the RDF (Resource Description Framework) schema to be used in extending the content model of the metadata element. The Resource Description Framework is defined in the W3C RDF Recommendation [RDFsyntax]. Other XML-based metadata formats may also be included in a smiliar manner. Note that if any content is added to the metadata element, a DOCTYPE must not be declared in the document.

17.4.12 Transition Effects Modules

The Transition Modules provide a framework for describing transitions such as fades and wipes. The Transition Modules define semantics for the transition element and the transIn and transOut attributes. The SMIL 3.0 Language profile includes the functionality of the BasicTransitions, TransitionModifiers and the FullScreenTransitions Module modules.

In the SMIL 3.0 Language profile, Transition Effects elements have the following attributes and content model :

This profile adds the transition element to the content model of the head element of the Structure Module.

The Transition Effects Modules add transIn and transOut attributes to ref, animation, audio, img, text, textstream, video and brush elements of the Media Object Modules.

The Transition Effects Modules add the transition value to the fill attribute for all elements on which this value of the fill attribute is supported.

17.4.13 Animation Module

The Animation Module provides a framework for incorporating animation into a timing framework, and a mechanism for composing the effects of multiple animations. The Animation Module uses the timing modules included in this profile for the underlying model of time. The SMIL 3.0 Language profile includes the animation functionality of the BasicAnimation module. The BasicAnimation Module defines the semantics for the animate, set, animateMotion and animateColor elements.

In the SMIL 3.0 Language profile, Animation elements may have the following attributes and content model :

This profile adds the animate, set, animateMotion and animateColor elements to the content model of the par, seq, excl and priorityClass elements of the Timing and Synchronization Modules. It also adds these elements to the content model of the body element of the Structure Module, to the content model of the a element of the Linking Modules and to the content model of the switch element of the Content Control Modules.

Specifying the target element of the animation

The animation target elements supported in the SMIL 3.0 Language profile are the region element defined in the Layout Modules, the area (anchor) element defined in the Linking Modules and the ref, animation, audio, img, text, textstream, video and the brush elements defined in the Media Objects modules.

The SMIL 3.0 Language profile uses the targetElement attribute to identify the element to be affected by animation elements. As recommended in the BasicAnimation Module when the targetElement attribute is supported, this profile excludes the XLink attributes href, type, actuate and show from the animate, set, animateMotion and animateColor elements.

Specifying the target attribute of the animation

The target attributes of the animations are a subset of those of the region, area (anchor) and media elements. The animatable attributes of the region, area (anchor) and media elements are listed in the table below.

The area (anchor) element has the coords attribute which may be subject to animation. The attribute coords is considered of type string in this profile. This means that only discrete non-additive animation is supported on this attribute.

The media elements have the following sub-region attributes which may be subject to animation: left, right, top, bottom, width, height, z-index and backgroundColor.

Integration definitions

The SMIL 3.0 Language profile defines a set of integration definitions as required by the Animation modules. These definitions are:

• Animation values in the SMIL 3.0 Language profile are subject to the same syntax requirements as the attribute values on the animated elements.
• Percentage values on the attributes have the same semantics as they do on the attribute. If percentage values are not supported on an attribute then percentage values are not supported for animation in the SMIL 3.0 Language profile.
• The SMIL 3.0 Language profile supports CSS2 [CSS2] color names as described in the Layout modules. The lower clamping bound color value is the black color or rgb(0%, 0%, 0%) and the higher clamping color value is the white color or rgb(100%, 100%, 100%). Values on an animated color lower than the lower clamping bound are clamped to the black color; values greater than the higher clamping color are clamped to the white color.
• The semantics of clamping values for attributes should be performed in floating point with a precision of at least that given by a 4-byte IEEE-format real number [IEEE-Arithmetic]. Cumulative and additive presentation values should be computed without regard to the range of the target attribute. Prior to display, the presentation value should be reduced or increased to the nearest value which is within the range of the target attribute. For integer attributes the computed value should then be rounded to the nearest integer (coerced-integer-value). The mathematical definition of rounding is:

  coerced-integer-value = Math.floor( interpolated-value + 0.5 )

• The position of the region element to which the animateMotion element applies is the top left corner, in the coordinate system within which the 'top' and 'left' attributes are defined in the Layout modules.
• The origin for the animateMotion when applied to the sub-region on media elements is the top left of the containing region as defined in the Layout modules.

17.4.14 State Modules

The State Modules provide a framework for declaratively manipulating various bits of state in a SMIL presentation. The State Modules define semantics for the delvalue, newvalue, send, setvalue, state and submission elements and the action, expr, language, method, name, ref, replace, submission and value attributes. The SMIL 3.0 Language profile includes the State functionality of the StateTest, UserState, StateSubmission, StateInterpolation modules.

In the SMIL 3.0 Language profile, the State elements may have the following attributes and content model:

This profile adds the state and submission elements to the content model of the head element of the Structure Module, and the setvalue, newvalue, delvalue and send elements to the content model of the body, switch, a, par, seq, excl, priorityClass elements. It also adds the expr attribute to all timed elements within the content model of the body element.

The content model of the state element is declared as empty. The state element defines the data model of the SMIL State engine using the language defined by the language attribute. If that language is XPath 1.0 the contents of the state element is an XML document that is not imported into SMIL 3.0 but needs to be declared using a namespace prefix. For other languages the contents of the state element are probably CDATA. Note that if any content is added to the state element, a DOCTYPE must not be declared in the document.

The submission attribute value is an IDREF that refers to a submission element.

The method attribute must at least support the values get, put and post. Serialization and submission must follow the description of these methods in [XFORMS10], section 11.2. Support for other methods described in that document is optional.

Interpolation of values using the mechanism from the StateInterpolation module is supported on the attributes for which animation is supported. Interpolation is also supported on the src, href, clipBegin and clipEnd attributes. Interpolation is disallowed on the Timing and Synchronization attributes. Use of interpolation on other attributes is implementation-dependent.

Expression Language and Data Model

Support for using XPath 1.0 as the expression language is required. Support for other languages is implementation-defined. The default value for the language attribute is http://www.w3.org/TR/1999/REC-xpath-19991116, which denotes the use of XPath 1.0 as the expression language.

When using XPath as the expression language, the content of the state element must be a single XML document. If this document is empty at initialization time a single empty <data/> root element is added.

When using XPath as the expression language the following constraints are in force:

• The expr attribute value is an XPath 1.0 expression that must evaluate to a boolean.
• The ref attribute value is an XPath 1.0 expression that must evaluate to a nodeset containing exactly one node.
• The target attribute value is an XPath 1.0 expression that must evaluate to a nodeset containing exactly one node.
• The value attribute value is an XPath 1.0 expression that must evaluate to a string.
• The name attribute value must be a valid XML element name.
• The newvalue element must have a name attribute. The ref attribute is optional and defaults to /*.

Interpretation of XPath expressions depends on an expression context. That context is defined thus:

• The context node is the root of the document defined in the state element.
• The context position and context size refer to that same root node.
• The variable bindings are empty.
• The function library consists of the functions defined in the StateTest module and the XPath Core Function Library.
• The set of namespace declarations is defined by the xmlns attribute on the context node.

This section is normative.

The SMIL 3.0 Language profile Document Type Definition is defined as a set of SMIL 3.0 modules. All SMIL 3.0 modules are integrated according to the guidelines in the W3C Note "Synchronized Multimedia Modules based upon SMIL 1.0" [SMIL-MOD], and defined within their respective module sections.

This section is normative.

The following royalty-free media formats should be supported:

• audio/basic [MIME-2]
• Ogg Vorbis audio (application/ogg) [VORBIS]
• image/png [PNG-MIME], [PNG-REC]
• image/jpeg [MIME-2], [JFIF] (See below)
• Ogg Theora video (application/ogg) [THEORA]

While many SMIL user agents support speciality media types for streaming audio and video content, SMIL user agent developers are also encouraged to support the following non-royalty-free media formats to further interoperability of SMIL content:

• audio/AAC (reference to follow)
• video/H264 (reference to follow)

Since both of these technologies are not freely available to user agent developers, the actual availability will remain player dependent.

<switch>
  <audio src="non-baseline-format-object" ... />
  <audio src="baseline-format-object" ... />
</switch>

17.6.1 JPEG Support

This section specifies the JPEG support recommended by a SMIL 3.0 implementations. The recommended support is targeted at specifying a level of functionality known to be compatibly supported within the industry and without licensing issues.

In general when people refer to JPEG [JPEG], they actually mean JPEG compressed images within the JFIF [JFIF] file format. JFIF was created by the Independent JPEG Group (IJG) for storing a single JPEG-compressed image in a file.

SMIL 3.0 User Agents should support JPEG images stored in a JFIF file [JFIF]. Other transport or storage mechanisms may be supported.

The following coding processes defined by the JPEG specification [JPEG], in Table 1, section 4.11, should be supported:

• Baseline process
• Extended DCT-based processes (with the exception of arithmetic coding).

The following statements also apply:

• 8-bit samples should be supported. 12-bit samples may be supported, (Section 4.7 [JPEG]).
• Support for the DNL Marker (Section 3.2 [JPEG]) is not required.
• Support for non-integer sampling ratios is not required. (A.1.1 [JPEG]).

The following encoding processes may be supported

• Complete Extended DCT-based processes.
• Lossless Processes
• Hierarchical Processes

SMIL 3.0 UA's should convert Y,Cb,Cr values compressed in the JPEG image to RGB as defined in the JFIF specification [JFIF] and may assume that the RGB values are sRGB.