Transformation dataflow in multimedia software engineering using TAO_XML: A component-based approach. Multimedia Software Engineering (MSE) is a new frontier for both Software Engineering (SE) and Visual Languages (VL). In fact multimedia software engineering can be considered as the discipline for systematic specification, design, substitution and verification of patterns that are often visual. Visual Languages give such contributions to MSE as: Visual notation for software specification, design and verification flow charts, ER diagram, Petri Net, UML visualization, visual programming languages etc. Multimedia Software Engineering and Software Engineering are like two sides of the same coin. On the one hand, we can apply software engineering principles to the design of multimedia systems. On the other hand, we can apply multimedia technologies to the practice of software engineering. In this paper we deal with the first of these topics. The aim of this paper is to demonstrate how it is possible to design and implement complex multimedia software systems using a TeleAction Object (TAO) transformer based on XML technology with a component-based multimedia software engineering approach. The paper shows a complete process of dataflow transformation that represents TAOs in different ways (text, TAO_XML, etc) and at different levels of abstraction. The transformation process is a reversible one. We will also show the first experiences conducted jointly from DIS, DCSI, and DMI laboratories using a tool named TAO_XML_T. The tool’s component-based architecture is also discussed in the paper.