From Media Annotations Working Group Wiki
The photo use case covers the extraction of semantics from photos, their annotation, and cross-application compatibility of annotation and organization tools and systems.
The photo use case is motivated by the need for a common exchange format of photo annotation to enable finding, sharing and reusing photos across the borders of single sites and tools. The use case discusses pros and cons of EXIF, XMP, PhotoRDF, DIG35 and MPEG-7 for using as a lingua franca among tools and sites. The conclusion of the use case authors is, that none of the standards is perfectly suited and that a "limited and simple but at the same time comprehensive vocabulary in a machine-readable, exchangeable, but not over complicated representation is needed"
An introduction to the mentioned standards like EXIF, XMP, PhotoRDF, DIG35 can be found in the MMSEM XG Vocabularies deliverable.
- Multimedia Semantics XG, http://www.w3.org/2005/Incubator/mmsem/
- Multimedia Annotation Interoperability Framework, W3C Incubator Group Editor's Draft 14 August 2007, http://www.w3.org/2005/Incubator/mmsem/XGR-interoperability/
- The photo use case, http://www.w3.org/2005/Incubator/mmsem/XGR-interoperability/#photo
- Multimedia Vocabularies on the Semantic Web, W3C Incubator Group Report 24 July 2007, http://www.w3.org/2005/Incubator/mmsem/XGR-vocabularies-20070724/