HTTP/2-Based Adaptive Streaming of HEVC Video over 4G/LTE Networks

HTTP Adaptive Streaming (HAS) is the de facto standard for over-the-top video streaming. In HAS, video content is temporally divided into multiple segments, each encoded at several quality levels. The client can select the quality level for every video segment, allowing smoother playback and a better user experience. Despite the ability of HAS to deal with changing network conditions, live streaming solutions often suffer from playout freezes and a large end-to-end delay. Reducing the segment duration can ameliorate this behaviour, since the client is able to respond faster to network changes and can use a lower temporal buffer size. However, since a request is required for every video segment, this approach is susceptible to high round-trip times (RTT). In this letter, the goal is the characterization of an HTTP/2 push-based approach with supershort segments in realistic network scenarios. We discuss the details of a measurement study we performed on the available bandwidth in real 4G/LTE networks, and analyse the induced bit rate overhead for super-short segments encoded with the H.265/HEVC standard. Evaluating the approach with the collected traces and generated content, we show that the proposed push-based approach results in a higher video quality (+6.4%) and a lower freeze time (-34.9%), and allows to reduce the live delay compared to traditional solutions over HTTP/1.1.