Tile Rate Allocation for 360-Degree Tiled Adaptive Video Streaming

360-degree video streaming commonly encodes and transmits the video as independently-decodable tiles to conserve bandwidth of regions out of the viewer's field of view (FoV). The bitrate of the tiles, however, can vary significantly across the tiles, complicating the choice of the representation to download for each tile in each segment to adapt to the bandwidth dynamics. In this paper, we model the tile rate allocation problem as a multiclass knapsack problem with a dynamic profit function that is a function of the FoV and the buffer occupancy. Experiments show that our approach can reduce bandwidth wastage by up to 41%, the number of stalls by up to 31%, stall durations by up to 26.5%, switches in quality by up to 20%, without sacrificing the quality of the tiles within the FoV, even when there are significant head movement and changes in FoV during streaming.