Prepare-Playback Rate And Priority Adaptive Bitrate Selection

HAS (HTTP-based Adaptive Streaming) based on ABR (Adaptive Bitrate Rate selection) has become a prevalent solution to media transmission. In order to improve the performance of HAS, many studies focus on how to reduce the unfairness, the instability and the inefficiency in a multi-clients scenario. However, the unfairness problem of the multi-clients with different priority levels and different playback rates, and the instability problem caused by the changes of the playback rate are still unresolved. To solve these problems, a novel ABR algorithm called PREPARE is proposed in this paper. In addition to normally considered throughput and client buffer information in HAS system model, the client priority and the playback rate are also incorporated to make the system model more accurate. With the feedback from servers, PREPARE algorithm is able to estimate the bandwidth much precisely and to reduce the unfairness among the multi-clients. The stability in bitrate selection is improved by introducing the buffer status in conjunction with the real-time playback rate. Moreover, the buffer underflow is prevented in download scheduling by advancing download according to the real-time playback rate. NS-3 simulator is used to evaluate the performance of PREPARE. The performance results show that PREPARE reduces the unfairness among multi-clients by more than 42 comparing to other three algorithms including ESTC, PANDA, FDASH. Meanwhile, PREPARE simultaneously keeps high stability and high efficiency.