Many new distributed multimedia applications involve dynamic multiple participants, have stringent end-to-end delay requirement and consume large amount of network resources. In this paper, we propose a new distributed dynamic delay-constrained least-cost multicast routing algorithm (DDDCLCMR) to support these applications. DDDCLCMR scales well because the source of the multicast tree needs only limited computation or may even not be involved in the route computation. When group membership changes, the existing multicast tree is perturbed as little as possible. Simulation results show that DDDCLCMR performs very good in terms of delay and cost for both, static and dynamic multicast groups, when compared to the best multicast algorithms known.