Rate partitioning for optimal quantization parameter selection in H.264 (SVC) based 4G broadcast/multicast wireless video communication

摘要

In this paper we present a novel scheme for video quality maximization in the context of H.264 scalable video coding (SVC) based 4G wireless broadcast and multicast video transmission. A typical wireless multicast group comprises of multimedia clients with varying wireless link qualities. Thus, the conventional fair rate static video (FRSV) transmission scheme, which aims to achieve QoS fairness in multicast video transmission is rate and hence quality constrained by the BMG subscriber with the worst link capacity. Hence, we propose a novel rate partitioning based scalable video (RPSV) transmission framework to overcome this limitation. The proposed RPSV scheme optimally partitions the multicast group for transmission of the H.264 coded base and enhancement scalable video layers. This is based on the Medium Grain Scalability (MGS) feature for enhancement layer coding in H.264 SVC. We demonstrate that the optimal wireless link quality based BMG partition and the associated quantization, time-fraction parameters can be computed by solving a series of convex objective minimization problems. RPSV naturally leads to a significant enhancement in the net multicast group video quality by avoiding the rate bottleneck otherwise caused by the worst link user, while simultaneously resulting in QoS fairness by avoiding service starvation of the user with the poorest link quality. We compare the resulting video quality obtained from the proposed RPSV based quantization parameter adaptation paradigm with the performance of the simplistic FRSV scheme and demonstrate the superiority of the former.