Abstract: 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.

Key words: video coding, image coding, screen content, screen image, compound image, survey