State of Play: Multimedia and Metadata

This is an installment in our ongoing State of Play series, designed to offer insight into new evolutions and significant issues in the online video industry.

Lack of Common Standard

During the last decade, lots of standardization efforts have gone into extending the Semantic Web. However, most efforts seem to have concentrated on the interchange of data and the representation of documents or HTML pages. When it comes to multimedia objects, there has been a lack of widely accepted protocols and/or ontologies.

There have been standardization efforts like MPEG-7 and MPEG-21 but they are known for their complexity and have largely been ignored on the web. Other open protocols, like those developed by the Open Archives Initiative (OAI-ORE, OAI-PMH) are being used for one specific purpose only. In practice, organisations have often resorted to the generic Dublin Core protocol, which is not particularly suited for representing multimedia. This has resulted in some industry standards like EBU-CORE or the IPTC protocols, but their usage is mostly limited to industry applications. More recently, there have been open initiatives like Microformats and RDFa vocabularies but none of them gained wide adoption. Finally, some corporations have defined their own proprietary standards: these include Google's YouTube Data API, Yahoo's Media RSS and Facebook's Open Graph Protocol.

Recent Activity

Following the Video on the Web Workshop in December 2007, the W3C released a Video in the Web Activity Statement: "The goal of this activity is to make video a 'first class citizen' of the Web. Video on the Web (and this includes audio, as the two are typically used together) has seen explosive growth, improving the richness of the user experience but leading to challenges in content discovery, searching, indexing and accessibility. Enabling users (from individuals to large organizations) to put video in the Web requires that we build a solid architectural foundation that enables people to create, navigate, search, link and distribute video, effectively making video part of the Web instead of an extension that doesn't take full advantage of the Web architecture."

As a result of the Video in the Web Activity, the Media Annotations Working Group was instituted. Its mission is to "provide an ontology and API designed to facilitate cross-community data integration of information related to media objects in the Web, such as video, audio and images". The ontology draft defines a core vocabulary of media properties and a set of mappings between the existing metadata formats. The API specification focuses on the methodology; it defines a client-side API to access the metadata. For both specifications, a Last Call Working Draft has been published.

Conclusion

Currently, there is no prevailing protocol or ontology for attaching metadata to multimedia resources. The 'Media Annotations Working Group' initiative could eventually lead to a widely accepted standard, but it still has a long way to go. In the meantime, users will have to look for a pragmatic approach based on existing standards and their own particular needs.

In order to permit Rambla customers to benefit from storing and managing their metadata at CDN level, we have released a metadata extension to our RAWS API's. These new metadata services - originally built into RAWS as the result of a research project funded by the Flemish Institute of Science and Technology (IWT) - are designed to give you maximum freedom and flexibility in choosing or defining your ontologies and can be extended to support different API's (like the one specified by the 'Media Annotations Working Group') in the future.