August 21, 2008
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More about Metadata: The Birth of PBCore
By Elaine Larson, AIT’s Director of Education
Version 1.1 of PBCore was published in January of this year, quickly followed by the release of the PBCore v1.1 XML Schema Definition (XSD). While this may not have been prominent on the radar screen of most users of instructional video, it is a “big deal” for all of the folks currently working to make public broadcasting media accessible to a growing digital media consumer population.
Essentially, PBCore—a project of the Corporation for Public Broadcasting, WGBH in Boston, and public broadcasters around the country—is a metadata dictionary. The goal of PBCore is to establish a standard metadata schema — or organizational structure—that will allow industry-wide sharing of content. As stated on the PBCore Web site, “PBCore is being used in public radio and television and beyond to describe, publish, and share content; and to allow others to find your content.”
PBCore is built on the foundation of the Dublin Core standard for content or resource discovery. Both contain a complex and comprehensive hierarchy of descriptors or elements for each piece of digital content. PBCore whittled the number of possible descriptive elements down to 53, including things like title, creator, date produced, copyright owner, description, audience, subject, and the like.
In the evolution from analog to digital content it has become crystal clear that it is essential to develop a method of describing that content which is consistent among content providers and distributors. As we turn traditional analog video content into the ones and zeroes of digital content, it is stored away in files on servers. This is great for keeping the content organized and safe. However, when we need to find and access that content, we must have some “tags” to grab hold of—tags that tell us exactly what we are getting. The quality and consistency of those tags in describing the digital content determine the accuracy of the retrieval. If we want a program on the Underground Railroad, for example, we don’t want to pull up a program on the history of the western expansion of the modern rail system. Accurate, standardized ways of organizing the information about a program help us get the program or information we want—and only that information.
There are broadcasting-specific reasons for developing a standard schema for public broadcasters, but the development of the PBCore has exciting implications for educators who use instructional media in their classrooms. The development of digital content has not only made video available through new technologies; it has also made it possible for an educator to use small segments of the video more effectively and easily. Teachers can combine the individual video learning objects with other media and text into multimedia presentations that engage and teach. Students can use this digital content in their own projects. The possibilities for using digital content for learning are developing at warp speed. Public broadcasters will continue to expand the ways they make their digital content available to teachers and students for these purposes.
And all of this is possible because each learning object—each “bit” of digital content—has been filed away with descriptive information that makes it possible to find, retrieve, and use it again…and again.
More more information about PBCore and how it can be utilized for instructional media, contact AIT’s Director of Education, Elaine Larson, at elarson@ait.net.