In this paper, we propose a unified framework, that we call UniMedia, for semanticsbased integration and management of multimedia data. The framework is an adaptation and extension of the federated database technology that has been developed during the past three decades for integrating disparate data sources of alphanumeric data. In particular, we propose a multimedia data model, that we call XML/M, which encompasses diverse types of multimedia data and captures semantic relationships among them. We develop the concept of container objects which cluster relevant multimedia data and customize them according to users' preferences. Further, we augment the concept of container objects with a version management technique. To validate utility of the UniMedia framework, we have implemented a prototype multimedia news management system.