This contribution is based on a research project that started in 1985 and dealt with the development of a theory for film adaptation studies. The project experimented with some specific theories of translation studies, called the polysystem (PS) theories of translation. It built on the hypothesis that there are important similarities between film adaptation - which the author calls audio-visual translation -, and translation. It became clear that both translation studies and adaptation studies could benefit from a closer collaboration with each other. In this article the author continues this argument. He starts out by giving a definition of audio-visual or media translation, thus indicating his position a a meta-level. Secondly some specific PS principles are explained in order to show important similarities between translations and adaptations. Finally the author concludes with a few words on a specific type of media translation: the translation of screenplays.