From Policy Languages Interest Group
PLING Feedback to Media Annotation WG
Meeting Media Annotations WG at TPAC 2009
Rigo Wenning met with the Media Annotations Working group at TPAC. MAWG explained that goal is only to establish an ontology for the translation between several languages for annotations. This translation is then used in an API to query annotations.
Together we reviewed ma:copyright and other hooks already existing in the ontology. One way to get privacy and rights languages connected would be for the MAWG to extend the set of metadata languages they are looking into. A possibility would be to add P3P and ODRL. Another possibility is to define ma:policy as suggested by Renato. A third possibility is to have a policy link established at the time of querying the API. A decision hasn't been made so far. Rigo promised to write a paragraph with Renato on how to hook policies with ma:policy and to send it to them for further discussion.
The PLING would like to see greater support for links to machine-interpretable policies as part of the web architecture. We recommend that the Media Annotations WG strongly consider this requirement for the "Ontology for Media Resource" WD . Specifically, we suggest that "ma:policy" be supported as a link (URI) to a policy. We do not expect that every application will understand the policy at the end of the URI, but they will at least be aware of the policy, and for those that do (such as CC , ODRL  etc) can then provide an improved service as the user interacts with the media.
Normative processing requirements
The answer can be like in P3P that applications understanding ma:policy would fetch the policy and determine from the XML namespace present in the found document, whether they understand it. If an application is not understanding ma:policy, it MUST skip the element.
I am assuming that all applications would understand ma:policy - that it simply holds a URI.
So, the question about "normative processing requirements" will need agreement on these options:
1 - applications MUST deference ma:policy 2 - applications MAY deference ma:policy 3 - applications MUST inform user there is a Policy (and give link) 4 - applications MAY inform user there is a Policy (and give link) 5 - others?
When ma:policy IS dereferenced, the options include:
A - Identify the Policy Namespace, and if understood, then PERFORM the policy B - Identify the Policy Namespace, and NOT understood, then inform the user C - others ?
I prefer 1 (3 is the minimum fallback) and A then B