A rate adaptation solution for distance education system over HTTP streaming

Adaptive streaming over Hyper-Text Transport Protocol (HTTP) is gradually being adopted by increasing network service providers. In order to combat the variable network resources, rate adaptation is adopted to meet the transmission rate of the varying network. However, being a resource-intensive application, a key research problem of rate adaptation is to make the best of bandwidth and provide a relatively stable high-quality media service. Besides, in HTTP streaming, it is difficult to differentiate between the short-term throughput changes which incurred by the TCP congestion control, and the throughput changes due to persistent bandwidth changes. Therefore, this problem becomes more challenging. In this paper, we propose a rate adaptation solution for our distance education system based on HTTP Live Streaming (HLS). Firstly, our solution adopts a bandwidth prediction algorithm based on download throughput samples, it can effectively measure the available bandwidth by dividing the segment into duration. Secondly, the solution proposes a threshold-based rate adaptation algorithm. We adopt two thresholds to design our adaptive strategy according to the predicted bandwidth, it successfully keeps our average bit rate in a higher level and gets a decent bandwidth utilization. At the same time, it provides a relatively stable video quality. Simulation results show that the proposed rate adaptation algorithm can strike a balance between bandwidth utilization and stability of video stream under a varying bandwidth condition.