Tile-Weighted Rate-Distortion Optimized Packet Scheduling for 360° Virtual-Reality Video Streaming

A key challenge of 360 degrees virtual-reality (VR) video streaming is ensuring high quality with limited network bandwidth. Currently, most of the studies focus on tile-based adaptive bit-rate streaming to reduce bandwidth consumption, where resources in network nodes are not fully utilized. This article proposes a tile-weighted rate-distortion (TWRD) packet scheduling optimization system to reduce data volume and improve video quality. A multimodal spatial-temporal attention transformer is proposed to predict viewpoint with probability that is used to dynamically weight tiles and their corresponding packets. The packet scheduling problem of determining which packets should be dropped is formulated as an optimization problem solved by a dynamic programming solution. Experiment results demonstrate that the proposed method outperforms the existing methods under various conditions.