The Semantics of MPEG-21Digital Items Revisited!

The Seman)cs of MPEG‐21  Digital Items  Chris&an Timmerer  Klagenfurt University (UNIKLU)  Faculty of Technical Sciences (TEWI)  Department of Informa&on Technology (ITEC)  Mul&media Communica&on (MMC)  h;p://research.)mmerer.com  h;p://blog.)mmerer.com  mailto:chris)an.)mmerer@itec.uni‐klu.ac.at  Co‐authors: Chris)an Timmerer (UNIKLU)  Maria Teresa Andrade, Pedro Carvalho  (INESC)  Davide Rogai (Comm.it)  Giovanni Cordara (TILAB)  ACKNOWLEDGMENTS Part of this work is supported by the European Commission in the context of the AXMEDIS (contract no.  511299) and ENTHRONE (contract no. 038463) projects. Further informa)on is available at h;p://www.axmedis.org and h;p:// www.ist‐enthrone.org respec)vely. 

Outline  •  Introduc)on  •  MPEG‐21 Digital Items  •  Use Cases and Data Models  •  Evalua)on (Criteria) and Discussion  •  Conclusions  Main source: MPEG core experiment conducted  2008/10/31  Chris)an Timmerer, Klagenfurt University, Austria  2 

(MPEG‐21) Introduc)on  Goal  •  … to enable transparent and augmented use of mul)media resources across a wide  range of networks, devices, user preferences, and communi)es, notably for trading  (of bits)  What ? – Digital Items (DIs)  •  A Digital Item (DI) is a structured digital object with a standard representa)on,  iden)ﬁca)on, and metadata within the MPEG‐21 framework  •  Digital Items are “the content” := (Media) Resources + Metadata + Structure  Who ? – Users   •  A User is any en)ty that interacts in the MPEG‐21 environment or makes use of a  Digital Item  •  Users will assume rights and responsibili)es according to their interac)on with  other Users  •  All par)es that have a requirement within MPEG‐21 to interact are categorized  equally as Users  2008/10/31  Chris)an Timmerer, Klagenfurt University, Austria  3 

Introduc)on (cont’d)  Issue  •  … possible to represent seman)cally similar (or equal) Digital Items  in diﬀerent ways  –  Structure and syntax elements    Impact on interoperability within and across applica)on domains  (e.g., automated produc)on, delivery, and consump)on within  heterogeneous environments)  Two types of interoperability inves&gated  •  Interop@DI: access/browse media resources and metadata,  process/consume the Digital Item as such  •  Interop@DID: processing of the DI’s representa)on (parsing,  valida)on)  2008/10/31  Chris)an Timmerer, Klagenfurt University, Austria  4 

e.g., Digital Item Iden)ﬁer  referring to ISBN, ISSN,  e.g., MPEG‐7, Dublin Core,  ISAN, ISRC, etc.  MPEG‐21 Digital Items  SMPTE, proprietary, etc.  Digital Item Model: abstract  terms and concept in EBNF  Digital Item Declara)on  Language (DIDL): XML  schema – building blocks    Item    Component    Descriptor  e.g., MPEG‐7, Dublin Core,    Resource  SMPTE, proprietary, etc.    Choice/Selec)on  DIDL document aka DID  => highly ﬂexible !!!  2008/10/31  Chris)an Timmerer, Klagenfurt University, Austria  5 

(Industry) Adop)ons  UPnP – DIDL‐Lite  •  Container format: UPnP specific (bitrate, resolu)on, etc.) + Dublin  Core  MPEG‐21, Part 4 – IPMPDIDL  •  Declara)on of protected Digital Items  MPEG Mul&media Applica&on Formats (MAFs)  •  “Profiles” Digital Items: subset of tools  MS Interac&ve Media Manager (IMM)  •  Implement DI model using OWL  •  Dublin Core + domain specific metadata (IPTC, EXIF, SMPTE) +  custom ontology predicates  •  Adopts Digital Item Iden)fica)on  => very/too flexible framework !!!  2008/10/31  Chris)an Timmerer, Klagenfurt University, Austria  6 

Use Case(s)  •  CP: ini)al DI (media resource + metadata)  •  SP: advanced Digital Item with respect to Service Level  Agreements (addi)onal metadata)  •  NP: network connec)vity service with QoS  •  CC: requests service (from SP) and consumes it (terminal)  2008/10/31  Chris)an Timmerer, Klagenfurt University, Austria  7 

Data Models  UCS 1: AXMEDIS  UCS 2: ENTHRONE  •  Composite Object  •  Composed and Final Items  •  Basic Object  2008/10/31  Chris)an Timmerer, Klagenfurt University, Austria  8 

Evalua)on Criteria  Interop@DID  Interop@DI  C.1 Conformance to DI model  C.8   Content browsing issues  C.2 Conformance to DIDL  C.9   Display metadata  C.3 Ambiguity of data models  C.10 Media rendering issues  C.4 DID parsing issues  C.11 Decode/Display DI as a  C.5 Supported building blocks  whole  C.6 Syntax restric)ons  C.7 Seman)c restric)ons  2008/10/31  Chris)an Timmerer, Klagenfurt University, Austria  9 

Evalua)on and Discussion  •  Players could somehow handle Digital Items  –  Metadata not understood is not displayed (i.e., ignored)  •  Choice/Selec)on not adopted  –  Mul)ple components instead with addi)onal seman)cs  defined  –  Only first component is displayed for first use case  •  Digital Item Iden)fica)on a requirement  •  Interpreta)on of media resources vs. metadata  –  Install media decoders – in necessary – on‐demand  –  How about metadata? “Metadata decoder” not defined!   Use proprietary metadata only internally  •  Presenta)on logic not mandated  2008/10/31  Chris)an Timmerer, Klagenfurt University, Austria  10 

Conclusions  •  Flexibility  –  Applica)ons implement only a subset  –  Add seman)c restric)ons to simplify DI handling  –  Allows the use of proprietary metadata  •  Flexibility leads to interoperability issues?  –  Does not invalid DID  –  Processing may lead to a loss of func)onality  –  Never (twice) the same DI (analogous to NTSC’s “never the  same color” or “never twice the same color”)  •  Need for addi)onal layer to homogenize the use of  MPEG‐21  –  Digital Item Processing (DIP)  –  Presenta)on of Structured Informa)on (PSI)  2008/10/31  Chris)an Timmerer, Klagenfurt University, Austria  11 

Conclusions (cont’d)  •  Digital Item Processing (DIP)  –  Sugges)ons of interac)on with the DI  –  Embed Digital Item Methods (ECMAScript, Digital Item  Base Opera)ons) which are presented to the User  •  Presenta)on of Structured Informa)on (PSI)  –  Extension of LASeR to point to certain parts of the DID  for presenta)on purposes  –  Actual presenta)on according to LASeR  •  Both require extension of MPEG‐21  2008/10/31  Chris)an Timmerer, Klagenfurt University, Austria  12 

Thank you for your a;en)on  ... ques)ons, comments, etc. are welcome …  >> Visit the IT campus Carinthia <<  >> h;p://www.it‐campus.at  <<   Ass.‐Prof. Dipl.‐Ing. Dr. Chris)an Timmerer  Klagenfurt University, Department of Informa)on Technology (ITEC)  Universitätsstrasse 65‐67, A‐9020 Klagenfurt, AUSTRIA  chris)an.)mmerer@itec.uni‐klu.ac.at  h;p://research.)mmerer.com/  Tel: +43/463/2700 3621 Fax: +43/463/2700 3699  © Copyright: Chris.an Timmerer  2008/10/31  Chris)an Timmerer, Klagenfurt University, Austria  13 

The Semantics of MPEG-21Digital Items Revisited!

by Alpen-Adria-Universität Klagenfurt on Dec 18, 2008

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