This section is informative.
The SMIL 2.1 specification leaves the SMIL 2.0 Metainformation Module [SMIL20-meta] unchanged.
This section is informative.
This section defines the SMIL 2.1 Metainformation Module composed of a
single module. This module contains elements and attributes that allow
description of SMIL documents.
Since these elements and attributes are defined in a module, designers of
other markup languages can choose whether or not to include this
functionality in their languages.
The World Wide Web was originally built for human consumption, and
although everything on it is machine-readable, this data is not
machine-understandable. It is very hard to automate anything on the Web, and
because of the volume of information the Web contains, it is not possible to
manage it manually. Metadata is "data about data" (for example, a library
catalog is metadata, since it describes publications) or specifically in the
context of this specification "data describing Web resources".
The solution proposed here is to use metadata information to describe SMIL
documents published on the Web.
The earlier SMIL 1.0 specification allowed authors to describe documents
with a very basic vocabulary using the element.
The SMIL 2.1 Metainformation module defined in this specification fully
supports the use of this
element from SMIL 1.0 but it also introduces new capabilities for describing
metadata using the Resource Description Framework Model and Syntax [RDFsyntax], a powerful meta information language
for providing information about resources.
This section is informative.
To insure backward compatibility with SMIL 1.0, the element as specified in the SMIL 1.0 [SMIL10] Recommendation can be used to define properties of a document (e.g., author/creator, expiration date, a list of key words, etc.) and assign values to those properties.
SMIL 2.1 extends SMIL 1.0 meta information functionalities with the new
element to host RDF
statements as RDF provides a more general treatment of metadata.
RDF is a declarative language and provides a standard way for using XML to
represent metadata in the form of statements about properties and
relationships of items on the Web. Such items, known as resources, can be
almost anything, provided it has a Web address. This means that you can
associate metadata information with a SMIL document, but also a graphic, an
audio file, a movie clip, and so on.
RDF is the appropriate language for metadata. The specifications for RDF can be found at:
Metadata information within an SMIL 2.1 document should be expressed in the appropriate RDF namespaces [XML-NS] and should be placed within the element. (See example below.)
RDF appears to be the ideal approach for supporting descriptors from multiple description schemes simultaneously.
Here are some suggestions for content creators regarding metadata:
Note: Individual industries or individual content creators are free to define their own metadata RDF Schema, but everyone is encouraged to follow existing metadata standards and use standard metadata schemas wherever possible to promote interchange and interoperability. If a particular standard metadata schema does not meet your needs, then it is usually better to define an additional metadata schema in RDF that is used in combination with the given standard metadata schema than to totally avoid the standard schema.
This section defines the elements and attributes that make up the functionality in the SMIL Metainformation module.
Element definition
The element is an empty
element.
Each element specifies a single
property/value pair in the name and content attributes, respectively.
Element definition
The element contains information that is also related to meta information of the document. It acts as the root element of the RDF tree. The element can contain the following child elements:
RDF element and its sub-elements (refer to W3C metadata Recommendations [RDFsyntax]).
This section is informative.
Here is an example of how metadata can be included in an SMIL document. The example uses the Dublin Core version 1.0 RDF schema [DC] and an hypothetic SMIL metadata RDF Schema:
<?xml version="1.1" ?>
<smil xmlns="http://www.w3.org/2005/SMIL21/Language">
<head>
<meta id="meta-smil1.0-a" name="Publisher" content="W3C" />
<meta id="meta-smil1.0-b" name="Date" content="1999-10-12" />
<meta id="meta-smil1.0-c" name="Rights" content="Copyright 1999 John Smith" />
<meta id="meta-smil1.0-d" http-equiv="Expires" content=" 31 Dec 2001 12:00:00 GMT"/>
<metadata id="meta-rdf">
<rdf:RDF
xmlns:rdf = "http://www.w3.org/1999/02/22-rdf-syntax-ns#"
xmlns:rdfs = "http://www.w3.org/2000/01/rdf-schema#"
xmlns:dc = "http://purl.org/dc/elements/1.1/"
xmlns:smilmetadata = "http://www.example.org/AudioVideo/.../smil-ns#" >
<!-- Metadata about the SMIL presentation -->
<rdf:Description rdf:about="http://www.example.com/meta.smi"
dc:Title="An Introduction to the Resource Description Framework"
dc:Description="The Resource Description Framework (RDF) enables the encoding, exchange and reuse of structured metadata"
dc:Publisher="W3C"
dc:Date="1999-10-12"
dc:Rights="Copyright 1999 John Smith"
dc:Format="text/smil" >
<dc:Creator>
<rdf:Seq rdf:ID="CreatorsAlphabeticalBySurname">
<rdf:li>Mary Andrew</rdf:li>
<rdf:li>Jacky Crystal</rdf:li>
</rdf:Seq>
</dc:Creator>
<smilmetadata:ListOfVideoUsed>
<rdf:Seq rdf:ID="VideoAlphabeticalByFormatname">
<rdf:li rdf:resource="http://www.example.com/videos/meta-1999.mpg"/>
<rdf:li rdf:resource="http://www.example.com/videos/meta2-1999.mpg"/>
</rdf:Seq>
</smilmetadata:ListOfVideoUsed>
<smilmetadata:Access smilmetadata:LevelAccessibilityGuidelines="AAA"/>
</rdf:Description>
<!-- Metadata about the video -->
<rdf:Description rdf:about="http://www.example.com/videos/meta-1999.mpg"
dc:Title="RDF part one"
dc:Creator="John Smith"
dc:Subject="Metadata,RDF"
dc:Description="RDF basic functionalities"
dc:Publisher="W3C Press Service"
dc:Format="video/mpg"
dc:Language="en"
dc:Date="1999-10-12"
smilmetadata:Duration="60 secs"
smilmetadata:VideoCodec="MPEG2" >
<smilmetadata:ContainsSequences>
<rdf:Seq rdf:ID="ChronologicalSequences">
<rdf:li rdf:resource="http://www.example.com/videos/meta-1999.mpg#scene1"/>
<rdf:li rdf:resource="http://www.example.com/videos/meta-1999.mpg#scene2"/>
</rdf:Seq>
</smilmetadata:ContainsSequences>
</rdf:Description>
<!-- Metadata about a scene of the video -->
<rdf:Description rdf:about="#scene1"
dc:Title="RDF intro"
dc:Description="Introduction to RDF functionalities"
dc:Language="en"
smilmetadata:Duration="30 secs"
smilmetadata:Presenter="David Jones" >
<smilmetadata:ContainsShots>
<rdf:Seq rdf:ID="ChronologicalShots">
<rdf:li>Panorama-shot</rdf:li>
<rdf:li>Closeup-shot</rdf:li>
</rdf:Seq>
</smilmetadata:ContainsShots>
</rdf:Description>
</rdf:RDF>
</metadata>
<!-- SMIL presentation -->
<layout>
<region id="a" top="5" />
</layout>
</head>
<body>
<video region="a" src="/videos/meta-1999.mpg" >
<area id="scene1" begin="0s" end ="30s"/>
<area id="scene2" begin="30s" end ="60s"/>
</video>
<video region="a" src="/videos/meta2-1999.mpg"/>
</body>
</smil>