The popularity of 360° and/or 4K videos has grown rapidly due to the immersive user experience. 360° videos are displayed as a panorama and the view automatically adapts with the head movement. Existing systems stream 360° videos in a similar way as regular videos, where all data of the panoramic view is transmitted. This is wasteful since a user only views a small portion of the 360° view. To save bandwidth, recent works propose the tile-based streaming, which divides the panoramic view to multiple smaller sized tiles and streams only the tiles within a user’s field of view (FoV) predicted based on the recent head position. Interestingly, the tile-based streaming has only been simulated or implemented on desktops. We find that it cannot run in real-time even on the latest smartphone (e.g., Samsung S7, Samsung S8 and Huawei Mate 9) due to hardware and software limitations. Moreover, it results in significant video quality degradation due to head movement prediction error, which is hard to avoid. Motivated by these observations, we develop a novel tile-based layered approach to stream 360° content on smartphones to avoid bandwidth wastage while maintaining high video quality. 

Next we explore the feasibility of supporting live 4K video streaming over wireless networks using commodity devices. Coding and streaming live 4K videos incurs prohibitive cost to the network and end system. We propose a novel system, which consists of (i) easy-to-compute layered video coding to seamlessly adapt to unpredictable wireless link fluctuations, (ii) efficient GPU implementation of video coding on commodity devices, and (iii) effectively leveraging both WiFi and WiGig through delayed video adaptation and smart scheduling.  Using real experiments and emulation, we demonstrate the feasibility and effectiveness of our system.

Lili Qiu is a Professor at Computer Science Dept. in UT Austin. She received a Ph.D. in Computer Science from Cornell University in 2001. She was a researcher at Microsoft Research (Redmond, WA) in 2001 -- 2004. She joined UT Austin in 2005. She is named IEEE Fellow, ACM Fellow, and ACM Distinguished Scientist. She has also received a NSF CAREER Award, Google Faculty Research Award, and best paper awards in Mobisys’18 and ICNP’17.