Many new distributed multimedia applications involve dynamic multiple participan ts, have stringent end-to-end delay requirement and consume large amount of ne twork resources. In this paper, a new DDDCLCMR (distributed dynamic delay-const rained least-cost multicast routing algorithm) is proposed to support these app lications. DDDCLCMR scales well because the source of the multicast tree needs o nly limited computation or may even not be involved in the route computation. Wh en group membership changes, the existing multicast tree is perturbed as little as possible. Simulation results show that DDDCLCMR performs very well in terms o f delay and cost for both static and dynamic multicast groups, compared with the best multicast algorithms known.