The wireless streaming media communications are fragile to the delay jitter because the conditions and requirements vary frequently with the users' mobility. Buffering is a typical way to reduce the delay jitter of media packets before the playback, however, it will incur a longer end-to-end delay. Our motivation in this paper is to improve the balance between the elimination of delay jitter and the decrease of end-to-end delay. We propose a novel adaptive playback buffer (APB) based on the probing scheme. By utilizing the probing scheme, the instantaneous network situations are collected, and then the delay margin and the delay jitter margin are employed to calculate the step length (sl) which is used to adjust the playback buffer in each time. The adaptive adjustment to the playback buffer in APB enables the continuous and real-time representation of streaming media at the receiver. Unlike the previous studies, the novelty and contributions of the paper are: a) Accuracy: by employing the instantaneous network information, the adjustment to the playback buffer correctly reflects the current network situations and therefore achieves the improved balance between the elimination of delay jitter and the decrease of end-to-end delay; Hence, APB adjustment is accurate in terms of improving such balance; b) Efficiency: by utilizing the simple probing scheme, APB achieves the current network situations without the complex mathematic predictions, which enables the adjustment to be more timely and efficient. Performance data obtained through extensive simulations show that our APB is effective to reduce both delay jitter and playback buffer delay.

This paper proposes a set of novel distributed algorithms on m-D mesh overlay configurations for short delay and low resource consumption application layer multicast. In contrast to previous approaches, our application layer multicast adopts two-layer tree architecture and the novelty and contribution are: (1) cluster formation algorithm assigns the closest group members into the same cluster that greatly decreases the multicast delay and resource consumption caused by the message transmission among the members with long distances; (2) optimal core selection algorithm seeks the cluster member who has the minimum sum of static delay distances to other cluster members as the optimal cores (i.e. cluster cores) that guarantees the short multicast delay; (3) weighted shortest path tree generation algorithm constructs a shortest path tree rooted at the optimal core for each cluster. The shortest path tree utilizes the minimum sum of links that are on the shortest paths among the cluster members; and (4) distributed multicast routing algorithm directs the multicast messages to be efficiently distributed along the two-layer multicast architecture in parallel without a global control. The extended simulation results indicate that the application layer multicast constructed by our algorithms is efficient in terms of short multicast delay and low network resource consumption as compared with other well-known existing multicast solutions.