The recent academic and commercial efforts in digital libraries have demonstrated the potential for white scale online search and retrieval of cataloged electronic content. By improving access to scientific, educational and historical documents and information, digital libraries create powerful opportunities for revamping education, accelerating, scientific discovery and technical advancement, and improving knowledge. Further more, digital libraries go well beyond traditional libraries in storing and indexing diverse and complex types of material such as images, video, graphics, audio, and multimedia. Concurrent with the advancements in digital libraries, the Internet has become a pervasive medium for information access and communication. With the broad penetration of the internet, network-based digital libraries can interoperate with other diverse networked information systems and provide around the clock real time access to widely distributed information catalogs.
Ideally the integration of the digital libraries and the Internet complete a powerful picture for accessing electronic content. However, in reality, the current technologies under lying digital libraries and Internet need considerable advancement before digital libraries supplant traditional libraries. While many of the benefits of the digital libraries result from their support for complex content, such as video, many challenges remain for enabling efficient search and transport. Many of the fundamental problems with digital video libraries will gain new focus in the Next Generation Internet (NGI) initiative.
DIGITAL VIDEO LIBRARIES
Digital video libraries deal with cataloging, searching, and retrieving digital video. Since libraries are designed to search large numbers of users, digital video libraries have greatest utility when deployed online. In order to effectively service users, digital video libraries need to efficiently handle both the search and transport of video.
The model for user interaction with the digital video libraries is illustrated in the figure. Video is initially added to the digital video libraries in an accessioning process that catalogs, indexes and store the video data. The user then searches the digital video library by querying the catalog and index data. The results are return to and browsed by the user. The user then has options for refining the search, such as by relevance feedback, and selecting items for delivery.
The two prevalent modes for delivering video to the user are video retrieval and streaming. In video streaming the video is played back over the network to the user. In many fast forward, reversed, pause, and so forth. In video retrieval, the video is down loaded over the network to the users local terminal. In this case, the video may be later viewed or used for other applications. Other forms of video information systems, such as video on demand (VOD), video conferencing, and video data base (VDB) systems, share characteristics with digital video libraries.
The system generally differs in their support for video storage, searching, cataloging, browsing, and retrieval. Video conferencing systems typically deal with the live, real time communication of video over networks. VOD systems deliver high bandwidth video to groups of users. VDBs deal with storing and searching the structured meta-data relative to video, but are not oriented to words video streaming or concurrent play back to large numbers of users.