A new quality optimization framework for dash streaming over wireless channels

Mobile devices are increasingly used as terminals for playback of multimedia content. However, maximizing the user´s quality of experience is challenging due to the highly variable conditions of the wireless channels. A possibility to cope with such a variability is to dynamically adapt the source coding rate during the transmission, which is the underlying idea of the DASH standard. This work proposes a new framework to improve the quality of the DASH-based streaming experience by allowing to adjust the tradeoff between the quality of received content and the risk of playback freeze due to an empty buffer, which is a strong quality-disruptive event. The problem is analytically formulated and an efficient method to compute the playback freeze probability as a function of the representation choices over time is presented. Numerous simulation results using real download rate traces of 3G channels show the performance improvement compared to other bandwidth-adaptive algorithms as well as the robustness of the framework to variations of its most important parameters.