Virtual-Competitors-Based Rate Control for 360-Degree Video Coding

360 video applications are attracting more attention in broadcasting systems. In the case of limited bandwidth, the bit fluctuation will affect the perception quality when transmitting 360-degree videos. To further optimize the bit allocation and reduce fluctuation, this paper proposes a virtual-competitors-based Rate Control (RC) algorithm for 360-degree video coding. The virtual competitors' concept is first proposed to balance the volatility of the bit between the adjacent GOPs. In addition, by introducing game theory, the virtual competitors-based frame-level bit allocation model is instructed. Furthermore, we propose a GOP-level bit allocation scheme with the average encoded bits of the historical GOP, the remaining bits of the encoded video sequence, and the number of unencoded GOPs. Based on the designed frame-level and GOP-level bit allocation scheme, the overall bit allocation method is proposed to implement the lower GOP-level bit fluctuation. Experimental results indicate the proposed method with the optimal RC Error, Bjontegaard Delta Peak-Signal-to-Noise-Ratio, Bjontegaard Delta Bit Rate, and bit fluctuation than the benchmarks, which validates the efficiency of the proposed method.