屏幕内容编码方法研究进展

Research Advances in Screen Content Coding Methods

随着云计算、虚拟桌面等的普遍推广,屏幕内容图像已成为新一代云——移动计算模型——不可或缺的一部分.研究压缩效率高、实时性好、复杂性适中的屏幕内容编码方法是目前视频编码领域的热点问题之一.从空间域、频率域、时间域和颜色空间4方面分析了屏幕内容图像的数据统计特性,进而重点阐述不连续色调图像的典型编码方法,将现有方法分为基于调色板-索引图的编码算法、基于模板匹配的编码算法、基于块匹配的编码算法、基于字典的编码算法、基于形状表示的编码算法以及时间域编码方法、色度编码方法,并进一步总结基于混合框架的屏幕内容编码方法,对各类算法的优势和存在的不足进行比较、分析和讨论.在此基础上,介绍了HEVC-SCC编码国际标准制定工作的进展,并对屏幕内容编码的未来发展趋势进行了展望.

With the widespread promotion of the applications such as cloud computing, virtual desktop, and so on, screen content image has become an integral part of the new generation of cloud- mobile computing model. It is one of the hot issues of video coding field to investigate the screen content coding methods with high compression efficiency, good real-time performance, and moderate computational complexity. On introducing the statistical characteristics of screen content image presented in the spatial domain, the frequency domain, the temporal domain, as well as the color space respectively, this study focuses on typical coding methods of the discontinuous tone images. The state-of-art methods are classified into seven categories, namely the palette-index map based methods, the template matching based methods, the block matching based methods, the dictionary- based methods, the shape representation based methods, the temporal-domain coding methods, as well as the chroma component coding methods. Then the screen content coding methods using a hybrid framework is further summarized. Meanwhile, the advantages vs. disadvantages of various methods are also compared, analyzed and discussed. Based on the above, the progress of drafting the international HEVC-SCC coding standard is introduced, and the development trend of the screen content coding is forecast in the near future.