Microsoft Interactive Media Manager
Metadata Model
White Paper
September 2008
John Devaney
Microsoft Corporation
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Applies To
Microsoft Interactive Media Manager
Microsoft Office SharePoint® Server 2007
Summary
Interactive Media Manager (IMM) uses Semantic Web technologies to provide enhanced metadata
management for media files. The use of Resource Description Framework (RDF) specification for
metadata and information modeling enables IMM to deliver a flexible notation platform, which you
can search by using SPARQL Protocol and RDF Query Language (SPARQL). IMM provides a default
ontology to represent objects and concepts. This open metadata World Wide Web Consortium (W3C)
description standard is used throughout the IMM Web Parts. The ontology is extensible and enables
users to define any object. Ontologies can be extended or developed by using the Microsoft Visual
Studio® 2005 or 2005 development system ontology add-on for IMM or the upcoming Metadata
Editor Web Part.
Figure 1 shows the position of the RDF Semantic Store in the IMM architecture.
Figure 1
Semantic Metadata Store position in the IMM architecture
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Contents
Summary................................................................................................................................................... 2
Contents ................................................................................................................................................... 4
Objectives ................................................................................................................................................. 5
Overview................................................................................................................................................... 5
Goals of the Interactive Media Manager Metadata Model ..................................................................... 6
The Semantic Web.................................................................................................................................... 6
Resource Description Framework Overview ........................................................................................ 6
Web Ontology Language Overview ...................................................................................................... 7
SPARQL Protocol and RDF Query Language ......................................................................................... 7
Interactive Media Manager Metadata Model .......................................................................................... 7
Interactive Media Manager Semantic Metadata Store ............................................................................ 8
IMM Ontology .......................................................................................................................................... 8
Ontology Definition in Interactive Media Manager ............................................................................. 9
Defining a New Ontology and Namespace ......................................................................................... 11
IMM Metadata Editor ......................................................................................................................... 11
Web Ontology Language ........................................................................................................................ 12
Working with Visual Studio 2005 ....................................................................................................... 12
Searching the IMM Repository ............................................................................................................... 13
IMM Semantic Metadata Service ....................................................................................................... 14
Conclusion .............................................................................................................................................. 15
Appendix 1 .............................................................................................................................................. 16
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Objectives
Set the business and technical landscape for the IMM metadata model.
Describe the structure of the metadata model.
Describe the key components of the IMM metadata model (RDF, OWL, and SPARQL).
Describe how to use the metadata model and its associated tools.
Overview
This white paper describes the technologies that the IMM metadata model uses to hold, manage, and
query IMM asset metadata. IMM is built on Microsoft Office SharePoint® Server 2007 technologies,
but it extends them in a number of areas, particularly in its use of RDF to model metadata. The use of
RDF triples means that IMM adds a new Semantic Metadata Store database, previously known as the
Metadata Repository, to the standard Office SharePoint Server search database. While enterprise
search is still available so that Office SharePoint Server 2007 users can find documents, the Semantic
Store database has an additional search function that uses SPARQL to mine media metadata. IMM is
developing a rich tool set that uses Web Parts and other Microsoft solutions, such as Visual Studio
2005 and 2008, to support the use and interrogation of the metadata model.
The paper describes the use of the Semantic Web, RDF, ontologies, Web Ontology Language, and
SPARQL in and with IMM.
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Goals of the Interactive Media Manager Metadata Model
IMM is designed to help users who work with rich media to ingest, manage, edit, and distribute
content. While IMM is based on Office SharePoint Server 2007 and offers collaborative capabilities,
enterprise content management, and search capabilities, IMM is designed specifically to work with
media files, and has been modified to integrate with the wider media industry. Key to this is the
addition of the IMM Semantic Metadata Store.
IMM uses Semantic Web technologies to express, interchange, store, and search media asset
metadata. This is because with RDF and OWL, developers and users can add business-specific and
technical information to media assets. Metadata stored in Digital Asset Management (DAM) systems
is often based on a variety of vocabularies and data models. This means that it is more difficult to
exchange metadata between disparate systems and different organizations. A fixed schema semantic
metadata store can also make it more difficult to change or extend the metadata model. The use of
RDF and OWL makes it easier to share information, both internally and with partners, because RDF
and OWL are W3C standards. The resulting metadata is stored in the Semantic Metadata Store. This is
a SQL Server 2005 or 2008–based RDF engine. Unlike a more traditional relational database, which
implicitly encodes the data semantics, the RDF has an open standard for specifying the semantics of
the data model.
For both technical and business users this means that IMM can integrate seamlessly with current,
proposed, or unknown DAM systems that use RDF or a relational database for metadata.
The Semantic Web
The term Semantic Web describes Tim Berners-Lee’s vision of a World Wide Web in which computers
can interpret information found on the Web. Berners-Lee states that: “For the semantic web to
function, computers must have access to structured collections of information and sets of inference
rules that they can use to conduct automated reasoning.” (Tim Berners-Lee, James Hendler, and Ora
Lassila. “The Semantic Web.” Scientific American Magazine, May 17, 2001.) IMM uses a Semantic
Web paradigm in the definition, interpretation, and interrogation of metadata in its metadata model.
Three of the formal specifications that are widely described as Semantic Web tools are:
Resource Description Framework (RDF)
Web Ontology Language (OWL)
SPARQL Protocol and RDF Query Language (SPARQL)
Resource Description Framework Overview
RDF is a W3C specification for metadata and information modeling. RDF is used to describe objects in
triples, which means that each object is referred to by subject, predicate, and object notation. The
subject refers to the resource, usually in the format of a universal resource indicator (URI), the
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predicate defines a feature of the object, and the object specifies a value for the feature. RDF triples
are also referred to as RDF graphs, because the visual representation of the data model can be made
as a graph of relationships between the subject, predicate, and object.
Web Ontology Language Overview
An ontology defines classes, properties and rules. An ontology to RDF is analogous to a schema for a
database. In an ontology, you define common things. Ontologies define objects and the types of
properties and property values that the objects can have. There might be ontologies for different
types of users, such as editors, but the RDF triples structure stays the same.
SPARQL Protocol and RDF Query Language
SPARQL Protocol and RDF Query Language (SPARQL) is an RDF query language designed to work with
triples. It can be compared to T-SQL for SQL database relational data, except that it is developed to
query RDF graph data.
Interactive Media Manager Metadata Model
The IMM metadata model is based on the use of RDF graphs to hold information about the resources
within a system. The triple structure means that there is no database schema that needs to be
modified if changes occur. New triples can be defined and included as new items are defined by your
business.
Figure 2
RDF Graph
In Figure 2, and the tabular representation in Table 1, you can see how the subject can have multiple
predicates and subjects. In spite of this, IMM demands that all triples are unique. The language and
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type options, which make up elements four and five of a triple, are used to define the language and
XML Schema Definition (XSD) type.
Table 1 – RDF Triple with Type
Subject
Predicate
Object
http://litwareinc/imm/resources/item1
dc:title
Finding Me
http://litwareinc/imm/resources/item1
dc:description
A young man loses his memory …
http://litwareinc/imm/resources/item2
Imm.videoFormat
http://www.litwareinc.com/imm/form
at/uid
http://litwareinc/imm/resources/item2
dc:title
Another Movie
http://litwareinc/imm/resources/item3
dc:description
In a state far away …
http://litwareinc/imm/resources/item4
dc:title
Another Movie II
Interactive Media Manager Semantic Metadata Store
The IMM Semantic Metadata Store is a Microsoft SQL Server 2005 or 2008–based RDF engine. The
key difference between the IMM Semantic Metadata Store and a more traditional relational database
is the representation of the data model semantics. A relational database uses database features, such
as foreign keys and tables, to encode semantics. This means that the client application must
understand how to interpret the database semantics, which can make it difficult to import data from
other sources because the semantics must be converted to match the current model.
In the RDF model, all tables, regardless of the source of the data, are the same format, as shown in
Table 1. This means that there is no need for complex changes to schemas to manage integration.
IMM Ontology
The IMM metadata model is based on the MPEG-21 Digital Item Declaration Language (DIDL) Abstract
Model (see ISO 21000-2 section 6.2) represented in an RDF formatting. The IMM ontology is designed
to maximize integration between multiple data sources by providing the majority of facilities for data
management. IMM uses the Dublin Core ontology, and the aim is for this ontology to be used across
all repository types. To cater to the majority of media description requirements, IMM also provides
the IMM ontologies. IMM applies the DIDL abstract model to base classes in the IMM Core OWL
ontology and extends the abstract base classes for use within the IMM framework.
The IMM Software Development Kit (SDK), documentation (available at
http://msdn.microsoft.com/en-us/library/bb971663.aspx) contains two versions of the IMM OWL
ontology: the IMM Full ontology and the IMM Core ontology. The Full ontology provides all of the
metadata and classes that can be used for video content, while the Core ontology provides all of the
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classes and a minimal set of metadata necessary for IMM Web Part and Workflow operation. The SDK
documentation primarily uses the IMM Core ontology in its examples.
The reference to definitive ontology namespaces, such as the Dublin Core, combined with the
function-specific ontologies from IMM means that the majority of class and metadata definitions
already exist, so that customers do not need to undertake large-scale ontology development. Instead,
they can extend the existing ontologies to include any unique items. For a full list of referenced
namespaces, see Appendix 1.
In addition to the classes and properties defined in an ontology, a customer can develop rules. Rules
can specify the properties, or lack of properties, that make a video item a video item, and different
from an audio item. Rules use a reasoned, rather than a defined, approach, so that identifying objects
within the core data uses rule-based deduction, rather than loading the date and then handling
exception errors. It is possible to extend rule sets or derive from existing rule sets. When a new
ontology is created, the developer can code an import at the top of the XML file and refer to an
existing file from Microsoft or elsewhere.
The same data is interpreted in different ways depending on the entry point—for example, user
types, customer accessing data, how data is used—which means that multiple rule sets are available.
This is particularly useful for workflow development because it is possible to define rules that identify
which files are metadata complete and which are not.
Ontology Definition in Interactive Media Manager
IMM metadata model elements can be created from the base Object class, as shown in Figure 3.
These might be items, such as VideoItem or ImageItem, or containers, such as folders or projects.
imm:Object Class – This is the base class that all classes in the model inherit from, and it provides
base-level functionality to all classes that are required by the IMM Web Parts. The Object class should
be treated as sealed.
did:Item Class – This is a first-level class derived from Object. An item most often represents a single
piece of data, a movie, or an audio file.
did:Container Class – This is a first-level class derived from Object. It represents a physical or logical
collection of objects.
MediaItem (did:Item) – This is a base class to be used for extending predicates. It should apply
globally to all media type items.
VideoItem (imm:MediaItem) –This is an instance and base class for items that are temporally based.
It can exist in either a digital or a physical format.
AudioItem (imm:MediaItem) – This is an instance and base class for all items that are audio only. It
can exist in either a digital or a physical format.
ImageItem (imm:MediaItem) – This is a base class, although it can be used to describe an instance. It
can store global image predicates along with extensions from image vocabularies.
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Folder (did:Container) – This class is a container-type virtual folder that exists only in metadata
through the Semantic Metadata Service.
Figure 3
Item and folder classes
Figure 4 shows an item instance. This can have properties based on the following:
IMM predicate or Dublin Core, custom, and domain specific properties.
Pointers to other related items, by using the did:ItemCollection predicate.
Pointer to an instance of type Resource, by using the did:Resource predicate.
Annotations, by using the IMM:AnnotationCollection predicate. An annotation can contain
custom predicates and pointers to Anchors.
did:Resource class, which points to the physical representation of an item. These are
equivalent to the MPEG-21 DID abstract Item Class.
did:Annotation class, which is a container for notes, digital ink, and other notations about an
item. Annotations can be anchored by time or location in an item.
did:Anchor class, which binds the annotation to its temporal or location point.
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Figure 4
Item Instance
All IMM items should be assigned a unique identifier. These are stored in the Digital Item
Identification (DII) (see ISO 21000-3) predicates provided in the IMM Core ontology. The predicates
are composed of two properties: identifier and type. In IMM, the type predicate should be a string
that identifies the Registration Authority or identification system used. It is optional if a valid Uniform
Resource Name is used in the identifier.
Defining a New Ontology and Namespace
There are a number of tools that you can use to create new or edit existing ontologies. In addition to
third-party tools, such as the Altova SemanticWorks Semantic Web tool, IMM version 2.0 will provide
the Metadata Editor Web Part (previously called the Ontology Editor Web Part).
IMM Metadata Editor
In IMM version 2.0, it will be possible to create and edit a unique ontology by using the IMM
Metadata Editor Web Part. The integration of the Metadata Editor allows IMM users to load an
existing ontology from the RDF data store via HTTP upload, and then modify the ontology by adding
or deleting classes, fields, and rules. Users can edit security at the ontology level, which gives users
and groups the ability to read, write, and view fields and classes of the ontology.
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The Metadata Editor provides access to definitions for fields, classes, rules and namespaces. In
addition, users can set a rollback point and can reset the ontology to the previous version to help
manage and standardize change. The Metadata Editor displays all of the associated classes for an
ontology, class descriptions, and namespaces. Users can also add fields from existing classes to the
specified class.
With the Metadata Editor, a user can create new classes; view, edit, and delete existing classes; and
edit class definitions and settings, such as permission and management. Fields across all classes can
be displayed in a Field Library, so that users can create new fields and view or edit existing fields.
Rules associated with an ontology are displayed in a Rules Library. This library enables users to create
new rules or copy an existing rule to a new rule. Rules can be filtered by title, description, or active
status.
Web Ontology Language
The Web Ontology Language (OWL) is a language with which you can write ontologies. IMM uses the
OWL Full implementation, which contains all of the OWL constructs and provides free, unconstrained
use of RDF constructs. IMM aims to be OWL-Full for the repository processing, although the .NET
classes are not OWL-Full.
Working with Visual Studio 2005
Visual Studio 2005 provides an Ontology Objects add-on that lets a user generate .NET classes from
an existing ontology file (see Figure 5). This replaces the Owl.exe tool that was made available for use
with earlier implementations of IMM.
Figure 5
Ontology Objects add-on
The Ontology Objects add-on is found in Visual C# Items. By using this add-on, you can create a new
ontology based on importing OWL files that are converted to C# classes. You can retrieve Web-based
or local files, as you can see in Figure 6.
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Figure 6
Ontology file selection
The add-on also parses required imports, such as Dublin Core elements, which you might have
included, as shown in Figure 7. The tool can find all of the classes and properties defined in the
selected ontology, and provide a URI for each.
Figure 7
Ontology imports selection
When you are happy with your selections, the add-on adds a new XML file to your Visual Studio
project. The new file provides a parsed RDF file and a .cs file with the generated classes. You can then
use these classes within the IMM API.
In addition to the editor options from IMM and Visual Studio, you can use a third-party ontology
editor, such as SemanticWorks from Altova.
Searching the IMM Repository
You can use SPARQL to query the IMM Semantic Metadata Store. The structure of a SPARQL query is
similar to that of a T-SQL query for a relational database. A SELECT statement defines the variables
that are returned as a table. In the WHERE clause in the SELECT statement, you insert triple patterns
(subject, predicate, and object). These can be wildcard (*) variables. The code sample shows a
SPARQL query over a graph pattern, or tree collection, of triple patterns.
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SPARQL Query
Statement Description Notes
PREFIX did: <urn:mpeg:mpeg21:2002:02-DIDMODEL-NS#>
PREFIX dc: <http://purl.org/dc/elements/1.1/>
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX imm: <http://schemas.microsoft.com/imm/core/1.0#>
SELECT ?title
WHERE
{
<guid:_ A101E8DE-C4F6-48a6-8DF3-E21034084282>
<did:ItemCollection> ?childId.
?childId <dc:title> ?title;
<rdf:type> <imm:MediaItem>.
}
Namespaces defined
?=variable, in this case
a variable called TITLE
{ defines graph pattern
start
Subject Predicate Object
Subject Predicate ;=same
object
Type is MediaItem
} defines graph pattern
end
The prefix for each namespace is declared at the top of a query, which makes it easier to read.
SPARQL is optimized for traversing an RDF graph. You can apply rule sets to a query by applying rules
from an ontology within the query. If necessary, you can convert a graph to a data table, for use with
more traditional tools, such as SQL, or to manipulate with an object-oriented language.
IMM Semantic Metadata Service
IMM components communicate with the Semantic Metadata Store through the Semantic Metadata
Service, previously known as the DAM Web Service. You can use an OLE DB driver to access the
database, but the WCF Web Service is preferred because it maintains the Service-Oriented
Architecture (SOA) of IMM.
The service interface provides methods for interacting with and retrieving graphs. This means that it
is possible to retrieve a graph without having to write SPARQL queries. The major IMM methods
available and their functional descriptions are shown in Table 2.
Table 2 – IMM Methods
Method
Description
GetResource
Accesses a resource when passed a subject and predicate(s). The method also
requires instruction on whether to get child items, such as Annotations. The method
returns RDF/XML, which can be processed on the client by loading the data into an
OW-generated object.
CopyResource
Clones a resource.
UpdateResource
Creates or updates a resource, depending on whether or not the resource already
exists.
DeleteResource
Climbs the graph to delete all triples that reference the resource and climbs down to
delete child items of the resource, if they are not child items of another object. Deletion
is permanent.
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An ontology is stored in the Semantic Metadata Store. Ontology methods that are similar to the RDF
methods include GetType, UpdateType, and DeleteType.
Conclusion
The IMM metadata model provides the flexibility and extensibility that is essential when working with
media assets. The use of Semantic Web technologies, such as RDF and SPARQL, means that IMM is
based on popular W3C industry standards. IMM can integrate with third-party storage and
management systems because the IMM SOA makes it possible to integrate easily, using well-defined
Web service APIs. IMM solutions are built on the highly successful Office SharePoint Server 2007
platform, which provides additional business support for an organization. Because IMM adheres to
established Web standards, an organization can be confident that interoperability with new tools
should be seamless.
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Appendix 1
Namespaces and qualified names are used within IMM.
QName
Namespace
Description
imm
http://schemas.microsoft.com/imm/core/2.0/
The base IMM framework namespace.
dc
http://purl.org/dc/elements/1.1
The Dublin Core namespace.
did
urn:mpeg:mpeg21:2002:02-DIDMODEL-NS#
The MPEG21 DID abstract model namespace.
didl
urn:mpeg:mpeg21:2002:02-DIDL-NS#
The MPEG21 Digital Item Declaration Language
namespace. This is the XML schema
implementation of the abstract model.
dii
urn:mpeg:mpeg21:2002:01-DII-NS#
The MPEG21 Digital Item Identifier Namespace
mediapro
http://ns.iview-multimedia.com/mediapro/1.0/
Microsoft Expression Media vocabulary (iView
Media Pro v3.1).
mpeg7
urn:mpeg:mpeg7:schema:2001#
The MPEG7 namespace used to define
broadcast metadata industry vocabulary
elements.
photoshop
http://ns.adobe.com/photoshop/1.0/
Adobe XMP Photoshop vocabulary.
xapRights
http://ns.adobe.com/xap/1.0/rights/
Adobe XMP Rights Management Schema.
xap
http://ns.adobe.com/xap/1.0/
Adobe XMP Basic Schema.
xmpMM
http://ns.adobe.com/xap/1.0/mm/
Adobe XMP Media Management Schema.
xmpDM
http://ns.adobe.com/xmp/1.0/DynamicMedia/
Adobe Dynamic Media Schema.
crs
http://ns.adobe.com/camera-rawsettings/1.0/
Adobe Camera Raw Schema.
tiff
http://ns.adobe.com/tiff/1.0/
Adobe EXIF Schema for TIFF.
exif
http://ns.adobe.com/exif/1.0/
Adobe EXIF Schema for EXIF-specific
Properties.
aux
http://ns.adobe.com/exif/1.0/aux/
Adobe EXIF Schema for Additional EXIF
Properties.
Iptc4xmpCore http://iptc.org/std/Iptc4xmpCore/1.0/xmlns/
IPTC core vocabulary for XMP.
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owl
http://www.w3.org/2002/07/ow
The Web Ontology Language namespace.
rdf
http://www.w3.org/1999/02/22-rdf-syntax-ns
The Resource Description Framework (RDF)
syntax.
rdfs
http://www.w3.org/2000/01/rdf-schema
RDF Schema.
xsd
http://www.w3.org/2001/XMLSchema#
XML Schema.
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