Institute of Information Systems & Information Management

RDFa-deployed Multimedia Metadata

Werner Bailer & Michael HausenblasGraz, 2007-08-10

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Where? Use Cases

What constitutes a ramm.x use case? Media assets are published on the Web Along with the media asset, the multimedia metadata

(as MPEG-7, Exif, ID3, etc.) is published The metadata itself are neither free-text nor natively

represented using an RDF-based vocabulary (as Music Ontology or OntologyX3D )

A Semantic Web agent wants to access the multimedia metadata

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Use Case: Photo Sharing (1) Exif information contains a lot of useful metadata Some photo sharing sites (as Flickr and PBase)

extract & display metadata

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Uses Case: Photo Sharing (2) Exif metadata in image is standardized But how to get it from a photo sharing site?

One can scrap the HTML code Use a web service, e.g. flickr.photos.getExif, returns

proprietary XML:<photo id="4424" secret="06b8e43bc7" server="2">

<exif tagspace="TIFF" tagspaceid="1" tag="271" label="Manufacturer">

<raw>Canon</raw>

</exif>

<exif tagspace="GPS" tagspaceid="3" tag="4" label="Longitude">

<raw>64/1, 42/1, 4414/100</raw>

<clean>64° 42' 44.14"</clean>

</exif>

</photo>

but no interoperability between different services!

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Use Case: Buy Music (1) Online music stores provide little metadata

(e.g. iTunes Store)

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Use Case: Buy Music (2) Metadata are available in common formats, as for

example ID3 Comprehensive online music databases (e.g.

http://musicbrainz.org/) exist, providing metadata either as proprietary XML or RDF

Offering music with metadata allows linking with Semantic Web resources about artists containing reviews recommendations etc.

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Use Case:Describe Video Structure

NBA publishes game summaries on YouTube

Published metadata are very poor As content is edited, information

about the structure of the clips is available, but YouTube does not support it

Video structure could for example be published as MPEG-

7 description allows accessing parts of the video, as

scenes showing a certain player

There may be a LOT of metadata, hence a kind of ”streaming” would be useful

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Use Case:Publish Professional Content

Content providers sell their content increasingly online, for example the BBC Motion Gallery

Metadata publishedwith content are notaccessible for auto-matic processing

Comprehensive metadata are available in-house in established representations(as SMEF, or EBU P_Meta)

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Use Case: Rights Metadata In simple cases, rights

metadata are just a link to a well-defined license (as Creative Commons)

More complicated rights information are usually available as huge text-only documents (e.g. Getty Images site)

DRM metadata formatsare available, e.g. inMPEG-21, a REL is defined

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Requirements Embed references to media assets in existing multimedia

metadata formats in (X)HTML Describe not only complete (X)HTML pages, but also certain parts of it Resulting description must be usable by an Semantic Web agent

Provide reference to services capable of mapping between a specific multimedia metadata format and RDF (formalisation)

Several descriptions may be available for a media asset (e.g. in different formats, covering different aspects) and there may be several ways to formalise the description available in a certain format

Due to amount of metadata, it may be necessary to "stream" the metadata in pieces related to spatio-temporal segments

Institute of Information Systems & Information Management

RDFa-deployed Multimedia Metadata

Werner Bailer & Michael HausenblasGraz, 2007-08-10