Improvement of re-sample template matching for lossless screen content video

Screen Content (SC) video coding becomes more important for screen sharing and screen broadcasting applications. There are many easy to see different characters between screen content video and camera-captured video. We proposed a template matching prediction method for lossless SC intra picture coding with higher compression ratio. The pixels are re-sampled to form the Virtual Largest Coding Unit (VLCU) firstly. About 80% pixels in VLCU can be predicted exactly by template matching with zero error. Then, pixels with non-zero prediction error should be coded with three information, index, position and value. Among these three, position will consume the most bits than the other two. In order to handle this challenge, we propose to apply the similarity of non-zero prediction error pixel positions of neighbor VLCU which can greatly help to improve the compression performance. The VLCU can be divided into sub CU as the same as the division in the standard High Efficiency Video Coding(HEVC) intra coding, and RDO is applied to find the best coding efficiency.