基于调色板模式的屏幕视频帧内编码快速算法

Fast intra algorithm of screen content coding based on palette mode

基于HEVC的屏幕视频编码根据屏幕视频的特征,引入了调色板模式、基于Hash的块匹配算法等新技术。这些新技术虽然提升了编码的质量,但同时增加了编码器的复杂度。为降低屏幕视频编码器的复杂度,提出了一种基于调色板模式的屏幕视频帧内编码快速算法。该算法结合了屏幕视频的特征和帧内编码模式的空间相关性,有效地减少了帧内编码单元的模式搜索范围。该算法可以在保证视频编码质量的前提下,有效降低编码复杂度,减少编码时间。在屏幕内容编码的标准测试平台SCM5.4的实验结果显示,本算法可以降低21%的编码时间,同时只引起0.93%的BD-Rate的上升。

The introduction of new technologies,such as palette mode,Hash-based block matching and so on,which are adopted by screen content coding（ SCC）,improves the quality of encoder. But at the same time,it increases its complexity. We propose a method which is applied on fast intra coding unit（ CU） mode decision of SCC,which aims at reducing the candidates of intra CU modes. This method combines characteristics of screen video content and spatial coherence of intra modes,and can effectively reduce the searching range of CU modes. The method can ensure the quality of coding,and significantly improve the efficiency of SCC intra frame coding. Experimental results show that the proposed method achieves about 21% time saving and 0. 9% BD-rate up compared with the SCC standard test mode 5. 4.