Arbitrary shape matching for screen content coding

In this paper, we present an arbitrary shape matching (ASM) coding technique for screen contents. In ASM coder, a Coding Unit (CU) is broken into multiple pixel sample strings. Each string called matched string in the CU has a matching string in the previously coded and reconstructed pixel buffer. Then the distance (either 1D or 2D) between the matching string and matched string and the length of the string are entropy-coded into the bitstream buffer. If the length is zero (no matching is found), then the original pixel sample is entropy-coded into the bitstream buffer. Experiments show that for some types of screen contents, ASM can significantly improve coding performance.