Overview

Multimedia metacomputing is a new approach to the management and processing of multimedia data in web-based information systems. It offers high flexibility and openness while shielding the applications from any system internals. This is achieved by realizing several abstraction concepts like device independence, location transparency, execution transparency, and data independence. However, format independence as an important aspect of data independence is well known to be fairly hard to realize, because it tends to reduce performance massively and, additionally, may lead to unexpected data loss.

To solve these problems, we introduce an advanced abstraction concept called transformation independence, which includes all concepts mentioned above, but adds some more concepts suitable for the metacomputing approach:

• a flexible materialization management,
• abstract, freely combinable media filters as the basic operators for metacomputing, and
• the concept of transformation requests, which express specific application semantics.

In the VirtualMedia project a formal model for specifying complex media operations as transformation requests and for processing and optimizing such requests is being developed.