Liu Zizheng, Pan Xiang, Li Yiming, Chen Zhenzhong
IEEE Trans Image Process. 2021;30:794-805. doi: 10.1109/TIP.2020.3038515. Epub 2020 Dec 4.
In this article, a new CTU-level bit allocation scheme aimed at subjectively optimized video coding for video conferencing applications is presented, in which the non-cooperative Stackelberg game is used for formulating and solving the bit allocation problem during the encoding process. Videos are divided into the Region of interests (ROI) which attracts people more and the non-ROI. The two regions are defined as the players in the game, where the ROI is the leader who takes the priority in strategy making and the non-ROI follows the leader's strategy. Based on the formulated game, the bit allocation problem can be expressed as a utility optimization problem. By solving the corresponding utility optimization problem, the bit allocation strategy between the ROI and the non-ROI will be established. Then the bits will be allocated to each CTU by a Newton-method-based algorithm for encoding, in which a trade-off between the ROI's quality and the overall quality can be achieved. Both the objective and subjective experimental results show that our proposed bit allocation method can improve the quality of ROI significantly with an acceptable overall quality degradation, leading to a better visual experience.
本文提出了一种新的CTU级比特分配方案，旨在针对视频会议应用进行主观优化视频编码，其中非合作Stackelberg博弈用于在编码过程中制定和解决比特分配问题。视频被分为更吸引人们的感兴趣区域（ROI）和非ROI。这两个区域被定义为博弈中的参与者，其中ROI是在策略制定上具有优先权的领导者，非ROI则遵循领导者的策略。基于所制定的博弈，比特分配问题可以表示为效用优化问题。通过求解相应的效用优化问题，将建立ROI和非ROI之间的比特分配策略。然后，通过基于牛顿法的算法将比特分配到每个CTU进行编码，从而可以在ROI质量和整体质量之间实现权衡。客观和主观实验结果均表明，我们提出的比特分配方法能够在可接受的整体质量下降的情况下显著提高ROI的质量，从而带来更好的视觉体验。
