Text-indexed video NPACs text-indexed video project combines basic research in video-on-demand technology, software design and implementation, and systems to provide an operational VoD service for educational applications. All development in this project is Web-based.
In contrast to entertainment oriented video dialtone systems where the content stream is nearly 100% video content, NPACs VoD project integrates video server technology within a larger information system. A video server management layer is linked to full text searchable databases and metadata used to access video content. This approach allows us to deliver digital video news-on-demand, educational documentary content, and multimedia coverage of events with educational relevance (e.g., a national political campaign event [Maxwell:96a]).
Examples of distance education applications of our VoD system include:
NPAC has focused on developing operational video server systems for education and related applications (e.g., decision support), while examining tradeoff s between image quality and bandwidth requirements. Transporting variable bit rate video streams (naturally occurring in video content) over a constant bit rate network channel (required in digital network delivery) requires a trade-off between image quality and bandwidth. Video compression techniques attempt to minimize the information content transmitted in each successive frames by carrying only the difference in scenes forward. The data requirements of displaying an action scene such as a sports event are much more demanding than for example a talk show [Podgorny:97a].