This section is informative.
The only change for to the Media Object Modules for SMIL 2.1 is the introduction of the paramGroup element to predefine sets of common param element values in the document head section and a facility to refer to these definitions from media object references within the body section. This change is made to reduce the size of a SMIL document containing many similar parameter definitions and to ease the authoring and maintenance of SMIL 2.1 documents that use the elements and attributes in the MediaParam Module.
This change has resulted in an expanded definition of the MediaParam module. In addition, several editorial changes have been made to the specification of other media object modules for the SMIL 2.1 release. These changes do not add or delete any functionality.
This section is informative.
This section defines the SMIL media object modules, which are composed of a BasicMedia module and five modules with additional functionality that build on top of the BasicMedia module: the MediaClipping, MediaClipMarkers, MediaParam, MediaAccessibility, and MediaDescription modules. These modules contain elements and attributes used to describe media objects. Additionally, a BrushMedia element is provided which can be used as a media object. Since these elements and attributes are defined in a series of modules, designers of other markup languages can reuse the SMIL media module when they need to include media objects into their language.
Changes with respect to the media object elements in SMIL 1.0 provide additional functionality that was brought up as requirements of the Working Group, and those differences are explained in Appendix A and Appendix B.
This section is normative.
SMIL provides a number of timing-related concepts that are used to determine activation, duration and termination of media objects in a presentation. The temporal semantics of these concepts are discussed in the SMIL 2.1 Timing and Synchronization module.
The distinction between continuous and discrete media is sometimes arbitrary and may be SMIL renderer dependent. For example, animated images that do not have a well-defined duration (simply a repeating collection of frames) are classified for SMIL scheduling purposes as being discrete media; such objects have an intrinsic scheduling duration of zero seconds.
This module defines the baseline functionality of a SMIL player. It is very close in functionality to the media object specification in SMIL 1.0.
This section is normative.
This section is normative.
SMIL defines a single generic media object element that allows the inclusion of media objects into a SMIL presentation. Media objects are included by reference (using a URI).
In addition to the ref element, SMIL allows the use of the following set of synonyms:
All of these media elements are semantically identical. When playing back a media object, the player must not derive the exact type of the media object from the name of the media object element. Instead, it must rely solely on other sources about the type, such as the type information communicated by a server or the operating system, or by using type information contained in the typeattribute.
Authors, however, should make sure that the group into which of the media object falls (animation, audio, img, video, text or textstream) is reflected in the element name. This is in order to increase the readability of the SMIL document. Some SMIL implementations may require the use of an element type that matches the information type of the object. When in doubt about the group of a media object, authors should use the generic "ref" element.
The animation element defined here should not be confused with the elements defined in the SMIL 2.1 Animation Module. The animation element defined in this module is used to include an animation (such as a vector graphics animation) by reference. This is in contrast to the elements defined in the Animation module, which provide an in-line syntax for the animation of attributes and properties of other elements.
Anchors and links can be attached to visual media objects, i.e. media objects rendered on a visual abstract rendering surface.
Languages implementing the SMIL BasicMedia Module must define which attributes may be attached to media object elements. In all languages implementing the SMIL BasicMedia module, media object elements can have the following attributes:
When the content represented by a URL is available in many data formats, implementations MAY use the type value to influence which of the multiple formats is used. For instance, on a server implementing HTTP content negotiation, the client may use the type attribute to order the preferences in the negotiation.
For protocols not enumerated in this specification, implementations should use the following rules: When the media is encapsulated in a media file and delivered intact to the SMIL user agent via a protocol designed for delivery as a complete file, the type attribute value should take precedence over other possible sources of the media type. For protocols which deliver the media in a media-aware fashion, such as those delivering media in a manner using or dependent upon the specific type of media, the application of the type attribute is not defined by this specification.
Element Content
Languages utilizing the SMIL BasicMedia module must define the complete set of elements which may act as children of media object elements. There are currently no required children of a media object defined in the BasicMedia Module, but languages utilizing the BasicMedia module may impose requirements beyond this specification.
This section is normative.
If the including profile supports the XMLBase functionality [XMLBase] , the values of the src and longdesc attributes on the media object elements must be interpreted in the context of the relevant XMLBase URI prefix.
This section is normative.
This section defines the elements and attributes that make up the SMIL MediaParam Module definition. Languages implementing elements and attributes found in the MediaParam module must implement all elements and attributes defined below, as well as BasicMedia.
This section is normative.
The param element allows a general parameter value to be sent to a media object renderer as a name/value pair. This parameter is sent to the renderer at the time that the media object is processed by the scheduler. Any number of param elements may appear (in any order) in the content of a media object element or in a paramGroup element. If a given parameter is defined multiple times, the lexically last version of that parameter value should be used.
The syntax of names and values is assumed to be understood by the object's implementation. This document does not specify how user agents should retrieve name/value pairs nor how they should interpret parameter names that appear multiple times within the same paramGroup element or as children of a media object.
Example
This section is informative.
<ref src="http://www.example.com/herbert.face"> <param name="mood" value="surly" valuetype="data"/> <param name="accessories" value="baseball-cap,nose-ring" valuetype="data"/> </ref>
This section is normative.
The paramGroup element provides a convenience mechanism for defining a group of media parameters that may be used with several different media objects. If present, the paramGroup element must appear in the head section of the document. The content of the paramGroup element consists of zero or more param elements. The paramGroup element may not contain nested paramGroup element definitions.
Element attributes
Examples
This section is informative.
This section contains several fragments that illustrate uses of the paramGroup element.
In the following fragment, a paramGroup is created to define parameters that are passed to several different media objects:
<smil ... > <head> ... <paramGroup id="clown"> <param name="mood" value="upBeat" valuetype="data"/> <param name="accessories" value="flowers,dunceCap"/> </paramGroup> ... </head> <body> ... <ref src="http://www.example.com/andy.face" paramGroup="clown"/> ... <ref src="http://www.example.com/sally.face" paramGroup="clown"/> ... </body> </smil>
In the following example, a media object provides an additional param value:
<smil ... > <head> ... <paramGroup id="clown"> <param name="mood" value="upBeat" valuetype="data"/> <param name="accessories" value="flowers,dunceCap"/> </paramGroup> ... </head> <body> ... <ref src="http://www.example.com/andy.face" paramGroup="clown"> <param name="gender" value="male"/> </ref> ... </body> </smil>
In this final example, a media object provides a duplicate param value. The behavior in this case depends on the media renderer; all param values are passed to the renderer in the lexical order of the SMIL source file. It is expected that the lexically last value for any parameter sent to the renderer be used, if possible.
<smil ... > <head> ... <paramGroup id="clown"> <param name="mood" value="upBeat" valuetype="data"/> <param name="accessories" value="flowers,dunceCap"/> </paramGroup> ... </head> <body> ... <ref src="http://www.example.com/andy.face" paramGroup="clown"> <param name="gender" value="male"/> <param name="mood" value="depressed" valuetype="data"/> </ref> ... </body> </smil>
This section is normative.
In addition to the element attributes defined in BasicMedia, media object elements can have the attributes and attribute extensions defined below. The inclusion or exclusion of these elements is left as an option in the language profile.
Values:
Example:
<par> <seq> <par> <img src="image1.jpg" region="foo1" fill="freeze" erase="never" .../> <audio src="audio1.au"/> </par> <par> <img src="image2.jpg" region="foo2" fill="freeze" erase="never" .../> <audio src="audio2.au"/> </par> ... <par> <img src="imageN.jpg" region="fooN" fill="freeze" erase="never" .../> <audio src="audioN.au"/> </par> </seq> </par>
In this example, each image is successively displayed and remains displayed until the end of the presentation.
Values:
As an example of how this would be used, many animated GIFs intrinsically repeat indefinitely. The application of mediaRepeat= "strip" allows an author to remove the intrinsic repeat behavior of an animated GIF on a per-reference basis, causing the animation to display only once, regardless of the repeat value embedded in the GIF.
When mediaRepeat is used in conjunction with SMIL Timing Module attributes, this attribute is applied first, so that the repeat behavior can then be controlled with the SMIL Timing Module attributes such as repeatCount and repeatDur.
Values:
This section is normative.
Any profile that integrates the erase attribute must define what is meant by "display area" and further define the interaction. See the definition of erase for more details.
The supported uses of the type and valuetype attributes on the param element must be specified by the integrating profile. If a profile does not specify this, the type and valuetype attributes will be ignored in that profile.
This section is normative.
This section defines the attributes that make up the SMIL MediaClipping Module definition. Languages implementing the attributes found in the MediaClipping module must implement the attributes defined below, as well as BasicMedia.
This section is normative.
Clip-value-MediaClipping ::= [ Metric "=" ] ( Clock-val | Smpte-val ) Metric ::= Smpte-type | "npt" Smpte-type ::= "smpte" | "smpte-30-drop" | "smpte-25" Smpte-val ::= Hours ":" Minutes ":" Seconds [ ":" Frames [ "." Subframes ]] Hours ::= Digit+ /* see XML 1.0 for a definition of ´Digit´*/ Minutes ::= Digit Digit; range from 00 to 59 Seconds ::= Digit Digit; range from 00 to 59 Frames ::= Digit Digit; smpte range = 00-29, smpte-30-drop range = 00-29, smpte-25 range = 00-24 Subframes ::= Digit Digit; smpte range = 00-01, smpte-30-drop range = 00-01, smpte-25 range = 00-01
Informative Note: The definition of Subframe value in
timecode introduces an inconsistency between SMIL 1.0 and SMIL 2.1.
At this time of revision, as some documents may have already been
written using this Subframe value we have decided not to delete it from
the Recommendation.
User agent should ignore subframe. Subframe should not be used as it is
deprecated.The value of this attribute consists of a metric specifier,
followed by a time value whose syntax and semantics depend on the
metric specifier.
The value of this attribute consists of a metric specifier, followed by a time value whose syntax and semantics depend on the metric specifier. The following formats are allowed:
The time value has the format
hours:minutes:seconds:frames.subframes. If the subframe value is
zero, it may be omitted. Subframes are measured in one-hundredths
of a frame.
Examples:
clipBegin="smpte=10:12:33"
clipBegin="npt=123.45s"
clipBegin="npt=12:05:35.3
"If no metric specifier is given, then a default of "npt=" is presumed.
When used in conjunction with the timing attributes from the SMIL Timing Module, this attribute is applied before any SMIL Timing Module attributes.
clipBegin may also be expressed as clip-begin for compatibility with SMIL 1.0. Software supporting the SMIL 2.1 Language Profile must be able to handle both clipBegin and clip-begin, whereas software supporting only the SMIL MediaClipping module only needs to support clipBegin. If an element contains both a clipBegin and a clip-begin attribute, then clipBegin takes precedence over clip-begin.
Example:
<audio src="radio.wav" clip-begin="5s" clipBegin="10s" />
The clip begins at second 10 of the audio, and not at second 5, since the clip-begin attribute is ignored. A strict SMIL 1.0 implementation will start the clip at second 5 of the audio, since the clipBegin attribute will not be recognized by that implementation. See Changes to SMIL 1.0 Media Object Attributes for more discussion on this topic.
See Changes to SMIL 1.0 Media Object Attributes for more discussion on this topic.
This section is normative.
This section defines the attribute extensions that make up the SMIL MediaClipMarkers Module definition. Languages implementing elements and attributes found in the MediaClipMarkers module must implement all elements and attributes defined below, as well as BasicMedia and MediaClipping.
This section is normative.
Clip-value-MediaClipMarkers ::= Clip-value-MediaClipping |
"marker" "=" URI-reference
/* "URI-reference" is defined in [URI] */
Example: Assume that a recorded radio transmission consists of a sequence of songs, which are separated by announcements by a disk jockey. The audio format supports marked time points, and the begin of each song or announcement with number X is marked as songX or djX respectively. To extract the first song using the "marker" metric, the following audio media element can be used:
<audio clipBegin="marker=#song1" clipEnd="marker=#dj1" />
This section is normative.
This section defines the elements and attributes that make up the SMIL BrushMedia Module definition. Languages implementing elements and attributes found in the BrushMedia module must implement all elements and attributes defined below.
This section is normative.
The brush element is a lightweight media object element which allows an author to paint a solid color or other pattern in place of a media object. Thus, all attributes associated with media objects may also be applied to brush. Since all information about the media object is specified in the attributes of the element itself, the src attribute is ignored, and thus is not required.
This section is normative.
Profiles including the BrushMedia module must provide semantics for using a color attribute value of inherit on the brush element. Because inherit doesn't make sense in all contexts, a profile may choose to prohibit the use of this value. The value of inherit is prohibited on the color attribute of the brush element for profiles that do not otherwise define these semantics.
This section is normative.
This section defines the elements and attributes that make up the SMIL MediaAccessibility Module definition. Languages implementing elements and attributes found in the MediaAccessibility module must implement all elements and attributes defined below, as well as MediaDescription.
This section is normative.
It is strongly recommended that all media object elements have an "alt" attribute with a brief, meaningful description. Authoring tools should ensure that no element can be introduced into a SMIL document without this attribute.
The value of this attribute is a CDATA text string.
Elements that contain alt, title or longdesc attributes are read by the assistive technology according to the following rules:
Example
<par> <video id="carvideo" src="car.rm" region="videoregion" title="Car video" alt="Illustration of relativistic time dilation and length contraction." longdesc="carvideodesc.html" readIndex="3"/> <audio id="caraudio" src="caraudio.rm" region="videoregion" title="Car presentation voiceover" begin="bar.begin"/> <animation id="cardiagram" src="car.svg" region="animregion" title="Diagram of the car" readIndex="2"/> <img id="scvad" src="scv.png" region="videoregion" title="Advertisement for Sugar Coated Vegetables" readIndex="1"/> </par>
In this example, an assistive device that is presenting titles should present the "scvad" element title first (having the lowest readIndex value of "1"), followed by the "cardiagram" title, followed by the "carvideo" element title, and finally present the "caraudio" element title (having an implicit readIndex value of "0").
This section is normative.
This section defines the elements and attributes that make up the SMIL MediaDescription Module definition. Languages implementing elements and attributes found in the MediaDescription module must implement all elements and attributes defined below.
This section is normative.
This attribute is deprecated in favor of using appropriate SMIL metadata markup in RDF. For example, this attribute maps well to the "description" attribute as defined by the Dublin Core Metadata Initiative [DC] .
The value of this attribute is a CDATA text string.
The value of this attribute is a CDATA text string.
xml:lang differs from the system-language test attribute in one important respect. xml:lang provides information about the content's language independent of what implementations do with the information, whereas system-language is a test attribute with specific associated behavior (see system-language in SMIL Content Control Module for details)
This section is informative.
With regards to the clipBegin/clip-begin and clipEnd/clip-end elements, SMIL 2.1 defines the following changes to the syntax defined in SMIL 1.0:
Using attribute names with hyphens such as clip-begin and clip-end is problematic when using a scripting language and the DOM to manipulate these attributes. Therefore, this specification adds the attribute names clipBegin and clipEnd as an equivalent alternative to the SMIL 1.0 clip-begin and clip-end attributes. The attribute names with hyphens are deprecated.
Authors can use two approaches for writing SMIL 2.1 presentations that use the new clipping syntax and functionality ("marker", default metric) defined in this specification, but can still can be handled by SMIL 1.0 software. First, authors can use non-hyphenated versions of the new attributes that use the new functionality, and add SMIL 1.0 conformant clipping attributes later in the text.
Example:
<audio src="radio.wav" clipBegin="marker=song1" clipEnd="marker=moderator1" clip-begin="npt=0s" clip-end="npt=3:50" />
SMIL 1.0 players implementing the recommended extensibility rules of SMIL 1.0 [SMIL10] will ignore the clip attributes using the new functionality, since they are not part of SMIL 1.0. SMIL 2.1 players, in contrast, will ignore the clip attributes using SMIL 1.0 syntax, because the SMIL 2.1 syntax takes precedence over the SMIL 1.0 syntax.
The second approach is to use the following steps:
Example:
<smil xmlns="http://www.w3.org/2005/SMIL21/PR/Language"> ... <switch> <audio src="radio.wav" clipBegin="marker=song1" clipEnd="marker=moderator1" system-required="smil2" /> <audio src="radio.wav" clip-begin="npt=0s" clip-end="npt=3:50" /> </switch>
SMIL 1.0 only allowed anchor as a child element of a media element. In addition to anchor (now defined in the Linking module), the param is now allowed as children of a SMIL media object. Additionally, other new children may also be defined by the host language.
The param element provides a generalized mechanism to attach media-specific attributes to media objects. The paramGroup element provides a convenience grouping mechanism to collect commonly used param element definitions into a single unit that may be referenced by multiple media objects.
A new brush element allows the specification of solid color media objects with no associated media.