An Incremental Data Structure for Multimedia Databases

The use of data at different levels of resolution, or multiresolution, is a common technique for improving performance of multimedia and scientific database applications, but is not yet systematically supported by database management systems. The sandbag construct, which has been previously suggested as a basis for a data model of multimedia and scientific databases, is a generalization of histograms that can model diverse types of data at different levels of resolutions or qualities. A sandbag can hold multimedia data such as motion video and represent incremental improvement in that data. It can be used conveniently to communicate multiresolution information between a standard DBMS and an application by adding a software layer between the DBMS and application. A mechanism for incrementally constructing sandbags of varying descriptiveness from individual facts is presented. A restriction is described that allows sandbags to be efficiently computed. A data structure and algorithms that implement fully incremental construction of sandbags under this restriction is provided. These algorithms have low-order polynomial worst case complexity and may be expected to be efficient in a practical implementation.