This paper deals with the coding of structure in region-based coders for moving sequences of images. The sequence of images is represented as spatio-temporal map of regions homogeneous regarded to motion-based criterion and characterized by their shape model, topological relations and motion parameters. Topological and geometrical models of spatio-temporal segmentation are introduced. The coding of geometrical information is formulated as the problem of the construction of the Eulerian circuit in planar non-connected graph. A suboptimal algorithm is proposed. Some results for teleconference sequence are given.