In this work, we propose a novel rate control algorithm for Versatile Video Coding (VVC) standard based on its distinct rate-distortion characteristics. By modelling the transform coefficients with the composite Cauchy distribution, higher accuracy compared with traditional distributions has been achieved. Based on the transform coefficient modelling, the theoretically derived R-Q and D-Q models which have been shown to deliver higher accuracy in characterizing RD characteristics for sequences with different content are incorporated into the rate control process. Furthermore, to establish an adaptive bit allocation scheme, the dependency between different levels of frames is modelled by a dependency factor to describe relationship between the reference and to-be-coded frames. Given the derived R-Q and D-Q relationships, as well as the dependency factor, an adaptive bit allocation scheme is developed for optimal bits allocation. We implement the proposed algorithm on VVC Test Model (VTM) 3.0. Experiments show that due to proper bit allocation, for low delay configuration the proposed algorithm can achieve 1.03% BD-Rate saving compared with the default rate control algorithm and 2.96% BD-Rate saving compared with fixed QP scheme. Moreover, 1.29% BD-Rate saving and higher control accuracy have also been observed under the random access configuration.

中文翻译：

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基于复合柯西分布的多功能视频编码高效码率控制

在这项工作中，我们基于其独特的速率失真特性，为通用视频编码 (VVC) 标准提出了一种新颖的速率控制算法。通过使用复合柯西分布对变换系数进行建模，实现了比传统分布更高的精度。基于变换系数建模，理论上推导出的 RQ 和 DQ 模型已被证明在表征具有不同内容的序列的 RD 特性方面具有更高的准确性，这些模型被纳入速率控制过程。此外，为了建立自适应比特分配方案，不同级别帧之间的依赖关系通过依赖因子建模，以描述参考帧和待编码帧之间的关系。给定派生的 RQ 和 DQ 关系，除了依赖因子之外，还开发了一种自适应比特分配方案以实现最佳比特分配。我们在 VVC 测试模型 (VTM) 3.0 上实现了所提出的算法。实验表明，由于适当的比特分配，对于低延迟配置，所提出的算法与默认速率控制算法相比可以实现1.03％的BD-Rate节省，与固定QP方案相比可以实现2.96％的BD-Rate节省。此外，在随机访问配置下也观察到了 1.29% 的 BD-Rate 节省和更高的控制精度。与默认速率控制算法相比，BD-Rate 节省 03%，与固定 QP 方案相比，BD-Rate 节省 2.96%。此外，在随机访问配置下也观察到了 1.29% 的 BD-Rate 节省和更高的控制精度。与默认速率控制算法相比，BD-Rate 节省 03%，与固定 QP 方案相比，BD-Rate 节省 2.96%。此外，在随机访问配置下也观察到 1.29% 的 BD-Rate 节省和更高的控制精度。