PD-RC: Perception-driven rate control for panoramic video coding based on energy distribution optimization

In immersive panoramic video (PV) encoding scenarios, PV exhibits larger flat regions compared to traditional videos. The existing intra-rate control methods in Versatile Video Coding (VVC) allocate the bitrate based on the construction of weights according to the energy distribution characteristics of different encoding blocks. However, in reality, the human visual system (HVS) is not sensitive to blocks with many flat regions in perception, which leads to excessive allocation of bitrate in insensitive regions. On the contrary, insufficient bitrate allocation in sensitive regions leads to the inability to achieve better reconstruction quality. To address this challenge, we propose a Perception-Driven Rate Control (PD-RC) strategy for panoramic video encoding based on energy distribution optimization, which makes the intra-rate control closer to the perception habits of HVS. Firstly, we propose a low-complexity filtering method guided by rate–distortion performance to optimize the energy distribution of I-frame features. Subsequently, leveraging the optimized perception features of the energy distribution, a perception-driven intra-mode coding-tree-unit-level rate control strategy is proposed to improve the coding performance for PV. Extensive evaluations show the performance of PD-RC over the state-of-the-art rate control methods of VVC. Specifically, in all-intra encoding mode, the average bitrate savings of PD-RC is −5.002%, while the average gain in weighted-spherically quality is 0.239 dB, with a rate exceeding the upper limit as low as 2%, and a reduction in encoding complexity gain of −0.163%. PD-RC effectively improves the rate control performance of PV intra-frame coding while saving computational overhead. It is significant for optimizing data transmission efficiency, enhancing video quality, and reducing storage costs. The source code will be available at https://github.com/liulinyun324/PD-RC.