Chen, Cheng YehCheng YehChenHUNG-YUN HSIEH2023-12-212023-12-212023-01-019798350333077https://scholars.lib.ntu.edu.tw/handle/123456789/638077Current solutions for tiling in viewport-aware 360° video streaming include fixed tiling and adaptive tiling. Fixed tiling often suffers from tradeoffs between transmission efficiency and encoding efficiency, thus degrading achievable quality of service on the client side. On the other hand, existing adaptive tiling solutions typically require fine-grained and dynamic tiling mechanisms, thus imposing higher computation overhead for both server and client sides. These limitations have thus hindered large-scale deployment of cost-effective 360° streaming systems. In this work, we propose an adaptive tiling mechanism that can effectively improve both encoding and transmission efficiency to facilitate light-weight virtual reality (VR) devices on large-scale 360° video service. We start by motivating the existence of 'sweet spots' for an equirectangular projection (ERP). If a user's viewport falls inside the region of sweet spots, the required bitrate to achieve high visual quality would be relatively small. We thus propose 'SweeTile' to make most viewpoints fall within the coverage of sweet spots by deploying 24 versions of 6\times 3 ERP with various rotations at the video server. Simulation results show that SweeTile improves both the encoding and transmission efficiency by 10% while incurring light computation on the video server and no extra computation on the end users.360° video streaming | adaptive tiling | viewport-aware tilingconference paper10.1109/ICCWorkshops57953.2023.102835362-s2.0-85177818638https://api.elsevier.com/content/abstract/scopus_id/85177818638