UKOLN is supported by: Content packaging and MPEG-21 DID Andy Powell, UKOLN, University of Bath [email_address] JISC Joint Programmes Meeting, July 2005, Cambridge www.bath.ac.uk a centre of expertise in digital information management www.ukoln.ac.uk

Contents why how PPS - I’m not really going to tell you how to use MPEG-21 DID since until 24 hours ago I knew pretty much nothing about it, but many thanks to Jeroen Bekaert and Herbert Van de Sompel of LANL for sharing their presentations and thoughts with me… PS - I’m only going to tell you how using MPEG-21 DID.

why

how

Why… … do we need packaging standards? because nothing in life is simple! applications tend to be built around aggregate objects of one kind or another digitised books (multiple parts, i.e. pages) learning objects (pathway thru multiple objects) even objects that look simple (e.g. an eprint in an eprint archive) turn out to be complex we need to exchange ‘complex objects’

… do we need packaging standards?

because nothing in life is simple!

applications tend to be built around aggregate objects of one kind or another

digitised books (multiple parts, i.e. pages)

learning objects (pathway thru multiple objects)

even objects that look simple (e.g. an eprint in an eprint archive) turn out to be complex

we need to exchange ‘complex objects’

Packaging standards framework for encoding ‘complex objects’ containing multiple objects and/or metadata may be nested often using XML as the encoding framework component objects embedded ‘by value’ XML fragments or Base64 encoding or … or passed ‘by reference’ URI like all standards, there are plenty to choose from: METS, IMS-CP, MPEG-21 DID, XFDU (CCSDS) http://dev.dcc.rl.ac.uk/twiki/bin/view/Main/ContentPackaging XFDU = XML Formatted Data Unit CCSDS = Consultative Committee for Space Data Systems

framework for encoding ‘complex objects’

containing multiple objects and/or metadata

may be nested

often using XML as the encoding framework

component objects embedded ‘by value’

XML fragments or Base64 encoding or …

or passed ‘by reference’

URI

like all standards, there are plenty to choose from:

METS, IMS-CP, MPEG-21 DID, XFDU (CCSDS)

Example 1 – digitised book consider digitised book in a ‘digital library’ complex object (book) made up of component parts (pages) the object and the parts each have one or more chunks of associated metadata parts may be embedded (by value) or linked (by reference) typical application: ‘virtual page turner’ typical packaging format: METS page book

consider digitised book in a ‘digital library’

complex object (book) made up of component parts (pages)

the object and the parts each have one or more chunks of associated metadata

parts may be embedded (by value) or linked (by reference)

typical application: ‘virtual page turner’

typical packaging format: METS

Example 2 – learning object consider a learning object (whatever that is!) complex object made up of one or more parts (other learning objects) documents, images, videos, interactive objects, audio files, maps, etc. each with IEEE LOM metadata some notion of workflow or sequencing ‘thru’ the parts typical application: VLE typical packaging format: IMS-CP PDF document learning object video multiple- choice test

consider a learning object (whatever that is!)

complex object made up of one or more parts (other learning objects)

documents, images, videos, interactive objects, audio files, maps, etc.

each with IEEE LOM metadata

some notion of workflow or sequencing ‘thru’ the parts

typical application: VLE

typical packaging format: IMS-CP

Example 3 - eprint eprints in eprint archives typically exposed using OAI-PMH currently repositories take different approaches to what they expose in their metadata work, or manifestations, or both eprint (work) PDF manifestation PDF (manifestation) MS-Word (manifestation) now: expose separate simple objects (metadata only) future: expose complex objects (metadata and full text) eprint (work) PDF Word

eprints in eprint archives typically exposed using OAI-PMH currently

repositories take different approaches to what they expose in their metadata

work, or manifestations, or both

Some observations… complex objects made up of component parts and metadata component parts need not be digital objects common approach to modelling objects crucial to interoperability unfortunately… a common approach to modelling is difficult to achieve especially on an international scale but no ‘best practice’ yet for how to model the complex objects found in eprint archives and institutional repositories

complex objects made up of component parts and metadata

component parts need not be digital objects

common approach to modelling objects crucial to interoperability

unfortunately… a common approach to modelling is difficult to achieve

especially on an international scale

but no ‘best practice’ yet for how to model the complex objects found in eprint archives and institutional repositories

MPEG-21 ISO standard that defines ‘ a normative open framework for multimedia delivery and consumption for use by all the players in the delivery and consumption chain ’ MPEG-21 is modular (17 parts!) Part 2: DID – representation of digital objects Part 3: DII – identification of digital objects Part 4: IPMP – enforcement of rights expressions Part 5: REL – declaration of rights expressions Part 7: DIA – transcoding based on contextual information Part 10: DIP – association of behaviors Part 16: BF – binary representation of digital objects parts can be (and are) used autonomously

ISO standard that defines ‘ a normative open framework for multimedia delivery and consumption for use by all the players in the delivery and consumption chain ’

MPEG-21 is modular (17 parts!)

Part 2: DID – representation of digital objects

Part 3: DII – identification of digital objects

Part 4: IPMP – enforcement of rights expressions

Part 5: REL – declaration of rights expressions

Part 7: DIA – transcoding based on contextual information

Part 10: DIP – association of behaviors

Part 16: BF – binary representation of digital objects

parts can be (and are) used autonomously

MPEG-21 DID ISO/IEC 21000-2: Digital Item Declaration second edition ISO standard representation of Digital Objects referred to as Digital Items 3 sections abstract model – DID representation of the Model in XML (DIDL) W3C XML Schema other representation of DID may emerge ISO/IEC 21000-16: Binary Format Resource Description Framework (RDF)?

ISO/IEC 21000-2: Digital Item Declaration

second edition ISO standard

representation of Digital Objects

referred to as Digital Items

3 sections

abstract model – DID

representation of the Model in XML (DIDL)

W3C XML Schema

other representation of DID may emerge

ISO/IEC 21000-16: Binary Format

Resource Description Framework (RDF)?

DIDL and digital libraries development of MPEG-21 largely driven by the big movie/video content owners and broadcast industries little widespread involvement by digital library community however, significant involvement of staff at LANL Research Library input into 2 nd edition of the standard ISO to publish the standard for free on the ISO Web site

development of MPEG-21 largely driven by the big movie/video content owners and broadcast industries

little widespread involvement by digital library community

however, significant involvement of staff at LANL Research Library

input into 2 nd edition of the standard

ISO to publish the standard for free on the ISO Web site

MPEG-21 DID model container item (sub-)item component resource (datastream) instantiated as DIDL/XML document represents the digital item/object/asset items (with optional nested sub-items) made up of one or more components, each of which has one or more datastreams Descriptor/Statement Descriptor/Statement Descriptor/Statement Descriptor/Statement metadata and/or identifier

Example – journal article Item Descriptor/Statement dii:identifier doi:10.1234/5678 Component Descriptor/Statement dcterms:created 2005-02-22 Resource @mimeType application/xml @ref http://example.org/getMeta?id=5678 Component Descriptor/Statement dcterms:created 2005-02-21 Resource @mimeType @ref Item Descriptor/Statement dii:identifier doi:10.1234/5678 Component Descriptor/Statement dcterms:created 2005-02-2 Resource @mimeType application/xml @ref http://example.org/getMeta?id=5678 Component Descriptor/Statement dcterms:created 2005-02-21 Resource @mimeType application/pdf @ref http://example.org/getPDF?id=5678 consider a ‘journal article’ digital asset comprising a PDF document and an XML metadata record (both by reference) the asset is mapped to a DIDL ‘Item’ element as follows… DIDL elements secondary info type value

consider a ‘journal article’ digital asset comprising a PDF document and an XML metadata record (both by reference)

the asset is mapped to a DIDL ‘Item’ element as follows…

MPEG-21 DIDL strengths MPEG-21 DID ‘abstract model’ provides a syntax-independent way of defining underlying ‘complex object’ model in use mapping between complex objects from different repositories combination of DID and MPEG-21 Digital Item Identification (DII) allows for unambiguous global identification of complex objects and their component parts

MPEG-21 DID ‘abstract model’ provides a syntax-independent way of

defining underlying ‘complex object’ model in use

mapping between complex objects from different repositories

combination of DID and MPEG-21 Digital Item Identification (DII) allows for unambiguous global identification of complex objects and their component parts

MPEG-21 DIDL strengths (2) DID model (and associated DIDL XML schemas) provide open, extensible framework in particular, the Descriptor/Statement mechanism provides a way of attaching arbitrary metadata (secondary information) to the digital object or any of its component parts checksums and/or signatures DC description rights metadata (MPEG-21 REL) etc.

DID model (and associated DIDL XML schemas) provide open, extensible framework

in particular, the Descriptor/Statement mechanism provides a way of attaching arbitrary metadata (secondary information) to the digital object or any of its component parts

checksums and/or signatures

DC description

rights metadata (MPEG-21 REL)

etc.

Final thoughts… some danger that discussion about packaging formats is a religious issue (i.e. don’t bring it up in a job interview!) the really difficult ‘issues’ are in the way that our complex objects are modelled applies to all the packaging formats, i.e the problem is independent of chosen packaging standard need widespread agreements about how we model our complex objects in order to achieve interoperability need to do that on an international basis

some danger that discussion about packaging formats is a religious issue (i.e. don’t bring it up in a job interview!)

the really difficult ‘issues’ are in the way that our complex objects are modelled

applies to all the packaging formats, i.e the problem is independent of chosen packaging standard

need widespread agreements about how we model our complex objects in order to achieve interoperability

need to do that on an international basis

Questions?