Multimedia Preservation Application Format

Multimedia Preservation Application Format

The successive waves of audio-visual technologies experiences by consumers in the last few decades are teaching one important lesson: every new technology creates a discontinuity Those who have created Super8 films and did not create a VHS copy risk losing their past. The same may soon happen to those who did not convert their Betamax or VHS cassettes to DVDs. Blu-Ray players seem to give more assurance because they play CDs, DVDs and Blu-Ray discs (and what about DivX?), but what if in a few years devices based on solid state technologies will be the only practically used to record media? I mention the case of old PowerPoint 95 presentations that can no longer be opened with the latest PowerPoint programs to signal the fact that preservation does not concern just the “physical layer”, but also the data format layer.

What can be a nuisance in the life of a consumer can be a big headache for organisations with the mission to preserve multimedia content that represent the collective memory of a community. They need to perform processes such as digitisation of analogue content or migration of digital content from one generation to the other. Large organisations typically perform these processes in house but smaller organisations outsource these processes to service providers.

Many organisations – archives, libraries, musea, etc. – already have digital preservation systems in place and they often need to exchange multimedia assets and related metadata, for example:

  • To exchange assets between preservation systems/repositories within the organization or with related organizations,
  • To change/upgrade their preservation systems,
  • To exchange content with service providers
  • To provide preservation services for other organisations.

At the time multimedia assets are exchanged there is a need to include preservation metadata as well in order to enable the receiving organisation to assess the integrity and fidelity of the assets it receives and to establish a baseline for its own curation and use of the assets. In addition to these metadata, the receiving organisation also needs information about any past preservation processes the assets and their descriptions that may include metadata about content, structure, and quality, as well as technical, historical and editorial information, and about ownership and usage rights and conditions.

Multimedia Preservation Application Format (MP-AF) is a standard that defines the content and format of Multimedia Preservation Description Information (MPDI), in order to facilitate interoperability between preservation systems, ensure accurate understanding of the resources’ exchanges, and reduce the risks of corruption both in the exchange and thereafter.

MPAF codes the following concepts relevant for multimedia preservation and used in preservation processes.

  • Provenance documents the chronology of events regarding the creation, modification, ownership and custody of resources. It provides information on the history of the multimedia content (including processing history);
  • Context describes the circumstances that resulted in the production of the audiovisual resource and how it relates to other relevant resources (e.g. why and how the resource was created, from which resources it was derived,  the relationship to other resources available in the package etc.);
  • Reference represents the information used for identifying and addressing the multimedia content and related resources. Reference information supports the linkage of identical or related resources that might be stored in separate repositories;
  • Quality encompasses information related to the qualitative or quantitative measurements of a given resource. It supports reasoning and evaluation of how good the resources have been preserved;
  • Fixity encompasses the information ensuring that resources are not altered in an undocumented manner.
  • Integrity represents the state of an entity (e.g. digital item) indicating the quality of being complete.
  • Authenticity encompasses information that enables an agent to verify if an object is correctly identified and free from (intentional or accidental) corruption;
  • Rights encompass information concerning legal, regulatory or contractual provisions affecting ownership, control, access or use of resources, as they impact the long term preservation (e.g. intellectual property, copyrights, privacy, etc.).

Here is a non-exhaustive list of technologies used in MP-AF

  1. MPEG-21 DII and DID supports preservation metadata such as provenance metadata, item identification and description
  2. MPEG-21 DIsupports structural relationships between the items
  3. MPEG‑21 Digital Item Semantic Relationships expresses relations between Digital Items
  4. MPEG-21 Rights Expression Language (REL, part 5) and MPEG-21 Contract Expression Language (CEL)/Media Contract Ontology (MCO) support rights metadata.