The distinguished features of screen contents lead to the development of the Screen Content Coding (SCC) extension of High Efficiency Video Coding (HEVC). Intra coding of HEVC-SCC has to evaluate traditional HEVC intra coding modes and additional modes for screen contents, which poses a challenge for coding such a content on mobile devices. Furthermore, the heterogeneous mobile devices have varying complexity requirements. In this paper, a flexible screen content intra coding scheme is proposed, which can trade between encoding complexity and rate-distortion performance degradation via cost sensitive learning. Taking the cost of different decisions into account, binary classifiers are designed to determine whether a particular kind of coding modes will be evaluated. By adopting the cost-proportionate weighted sampling, the proposed scheme can learn a flexible coding policy offline via reinforcement learning. Experimental results show the effectiveness of the proposed scheme.

屏幕内容的显着特征导致了高效视频编码（HEVC）的屏幕内容编码（SCC）扩展的发展。HEVC-SCC的帧内编码必须评估传统的HEVC帧内编码模式和屏幕内容的其他模式，这给在移动设备上编码此类内容提出了挑战。此外，异构移动设备具有变化的复杂性要求。本文提出了一种灵活的屏幕内容帧内编码方案，该方案可以通过成本敏感型学习在编码复杂度和速率失真性能下降之间进行权衡。考虑到不同决策的成本，二进制分类器被设计为确定是否将评估一种特定类型的编码模式。通过采用成比例的成本加权抽样，该方案可以通过强化学习离线学习灵活的编码策略。实验结果表明了该方案的有效性。