Much work has been done to study the rate control problem in variable bit rate ( VBR) video coding system. Most of them consider the point-to-point cases, wher e the rate control problem can often be abstracted as how to allocate bits among frames or among blocks when available bandwidth is limited. While in some other cases, such as some wireless ATM systems, multi-users share the common limited bandwidth. In such conditions, the bandwidth allocation among different users b ecomes a rather important problem.In this paper, a novel bandwidth allocation s cheme is presented, where the available bandwidth is dynamically allocated a mong different users based on a so-called "equal distortion" criterion. Simulatio n results show that the proposed scheme considerably improves the overall subjec tive performance in multi-user VBR communication systems. It is noticed that th e proposed join source and channel rate control idea is a very general concept t hat can be useful in many similar problems.