Recently specific middlewares have been proposed while those with general capabilities are going to be integrated into the most diffused development platforms and operating systems. This trend has provoked the production of middlewares for industrial automation, home automation, multimedia, etc. In the paper a solution to model a Multimedia middleware is proposed as related to AXMEDIS EC R&D Project in which an MPEG21 compliant content factory is modeled. In that case, the middleware is used for sharing software components dedicated to the content processing and production. In the paper, the architecture of the DISIT-M3W is presented, depicting the general architecture, the class structure, the interactions among components and services, etc. by using the UML formalization.