A Universal String Matching Approach to Screen Content Coding

Abstract

This paper proposes a universal string matching (USM) approach to screen content coding (SCC). USM uses a primary reference buffer and a secondary reference buffer for string matching and includes three modes: general string (GS) mode, constrained string 1 (CS1) mode, and constrained string 2 (CS2) mode. The CS1 mode and CS2 mode are constrained cases of the GS mode. Due to the diversity of the screen content, each of the three modes plays an indispensable role in coding some types of screen content . When using USM to code a coding unit (CU) , one of the three modes is selected to code the CU. Compared with high-efficiency video coding (HEVC) SCC reference software HM-16.6 + SCM-5.2 of full frame search range for intrablock copy, USM achieves an average Y BD-rate of –28.4% for five text and graphics with motion (TGM) sequences from the audio video coding standard SCC common test condition (CTC) test suite and –5.8% for eight TGM test sequences from the HEVC SCC CTC test suite in all intraconfigurations, with a nearly 10% decrease in encoding runtime and almost the same decoding runtime.