Structural similarity (SSIM)-based distortion $\text {D}_{\text {SSIM}}$ is more consistent with human perception than the traditional mean squared error $\text {D}_{\text {MSE}}$ . To achieve better video encoding quality, many studies on optimal bit allocation (OBA) used $\text {D}_{\text {SSIM}}$ as the distortion metric. However, the MSE-based rate distortion optimization (RDO) was still used in these studies. The inconsistency between the optimization goals of OBA and RDO results in a non-optimal SSIM-based encoding performance. To solve this problem, we propose an accurate coding tree unit level $\text {D}_{\text {SSIM}}-\text {D}_{\text {MSE}}$ model, which enables performing the SSIM-based RDO with simpler R- $\text {D}_{\text {MSE}}$ cost scaled by the SSIM-based Lagrangian parameter ${\lambda _{\text {SSIM}}}$ . Moreover, based on this model, the R- $\text {D}_{\text {SSIM}}$ model can be accurately estimated based on the joint relationship of R- $\text {D}_{\text {SSIM}}-{\lambda _{\text {SSIM}}}$ . With the accurate R- $\text {D}_{\text {SSIM}}$ model, the SSIM-based OBA problem is then solved. Accordingly, the SSIM-based OBA and SSIM-based RDO are unified together in our scheme, called SOSR. Compared with the HEVC reference encoder HM16.20, SOSR saves 5%, 11%, and 17% bitrate under the same SSIM in the commonly used all-intra, hierarchical and non-hierarchical low-delay-B configurations, which is superior to existing state-of-the-art SSIM-based OBA schemes.

中文翻译：

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基于 SSIM 的 CTU 级比特分配和速率失真优化的联合优化

基于结构相似性 (SSIM) 的失真 $\text {D}_{\text {SSIM}}$ 比传统的均方误差更符合人类的感知 $\text {D}_{\text {MSE}}$ . 为了获得更好的视频编码质量，许多关于最佳比特分配 (OBA) 的研究使用了 $\text {D}_{\text {SSIM}}$ 作为失真度量。然而，这些研究中仍然使用基于 MSE 的速率失真优化 (RDO)。OBA 和 RDO 的优化目标之间的不一致导致基于 SSIM 的编码性能非最佳。为了解决这个问题，我们提出了一个准确的编码树单元级别 $\text {D}_{\text {SSIM}}-\text {D}_{\text {MSE}}$ 模型，它可以使用更简单的 R- 执行基于 SSIM 的 RDO $\text {D}_{\text {MSE}}$ 由基于 SSIM 的拉格朗日参数缩放的成本 ${\lambda _{\text {SSIM}}}$ . 此外，基于该模型，R- $\text {D}_{\text {SSIM}}$ 基于R-的联合关系可以准确估计模型 $\text {D}_{\text {SSIM}}-{\lambda _{\text {SSIM}}}$ . 用准确的 R- $\text {D}_{\text {SSIM}}$ 模型，然后解决基于 SSIM 的 OBA 问题。因此，基于 SSIM 的 OBA 和基于 SSIM 的 RDO 在我们的方案中统一在一起，称为 SOSR。与HEVC参考编码器HM16.20相比，SOSR在常用的all-intra、hierarchical和non-hierarchical low-delay-B配置下，在相同SSIM下分别节省5%、11%、17%的码率，优于现有最先进的基于 SSIM 的 OBA 方案。