Multimedia Databases: Integrated Storage and Retrieval of Text, Images, Sound, and Video

New hardware offered at reasonable prices allows to develop improved user interfaces for computer systems: I/O devices can capture and present not only text and graphics, but also photos, sound, and video; storage devices (mainly optical disks) provide the capacity needed for those types of data. The effect is not only better user interfaces, but also more information held in the system. Applications that use multimedia thus have to handle I/O on one hand and storage and retrieval of images, sound, video, etc. on the other. Multimedia databases are being developed to reduce the burden for the programmer with respect to the second task. They provide powerful operations to store and retrieve the multimedia data objects while insulating the programs from the specifics of the new storage devices and the plethora of data formats. In this paper we describe the tasks of a multimedia database management system in more detail. An overview is given of the new types of data that have to be managed, i.e. text, graphics, image, sound, and video. This shows how the data objects look like, what their size and structure are, and how they are accessed from various applications. Then, the embedding of those data objects into a data model is discussed. While many researchers claim that a multimedia database must be object-oriented, a way of extending relational systems for multimedia is also shown. The paper concludes with an outlook on the important problem of search in large sets of multimedia data objects and with a discussion of architectures for multimedia database management systems.