The present invention pertains to an apparatus and method for adding a graphic element, such as a subtitle to selected locations of the frames in a 3D movie. The authoring tool receives a depth map indicating the position of various objects in the frames of 3D content along a Z-axis. The authoring device then designates a position for at least one additional graphic element in at least some of the frames, these positions being determined in relation either to the positions of the objects or the position of the screen along said Z-axis. An encoder uses parameters from the authoring tool to reauthor the 3D movie by adding the graphic content to the positions designated by the parameters.