Visual Attention-Aware Omnidirectional Video Streaming Using Optimal Tiles for Virtual Reality

Owing to its interactive look around nature and very large resolution requirement, providing immersive omnidirectional video (ODV) streaming experiences in virtual reality applications demands cost-effective solutions to meet both the content delivery network and device constraints. In this paper, we introduce an adaptive ODV streaming pipeline that optimizes dynamic adaptive streaming over HTTP representations of ODV content considering their visual attention (VA) maps. The main contribution of this paper is the use of VA maps: 1) to compute a novel objective quality metric that captures the fact that not all of the ODV is actually watched by users: the VA spherical weighted-based objective quality measurement; 2) to define optimal tile representations of the ODV frames, namely, tiling schemes, which are composed of variable-sized and non-overlapping tiles; and 3) to efficiently distribute a given bitrate budget among the set of tiles within a tiling scheme for an ODV. We evaluate the proposed system performance with varying bandwidth conditions and the tracked head orientations from user experiments. Results show that the proposed system significantly outperforms the existing non-tiled and tile-based streaming solutions.