Pseudo 2D String Matching Technique for High Efficiency Screen Content Coding

• Published in: IEEE transactions on multimedia Vol. 18; no. 3; pp. 339 - 350
• Main Authors: Zhao, Liping, Lin, Tao, Zhou, Kailun, Wang, Shuhui, Chen, Xianyi
• Format: Journal Article
• Language: English
• Published: Piscataway IEEE 01.03.2016; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Color; Decoding; Encoding; Indexes; Pattern matching; Shape; Streaming media; hash-table; string matching; high efficiency video coding (HEVC); screen content coding (SCC); Block matching
• ISSN: 1520-9210; 1941-0077
• DOI: 10.1109/TMM.2015.2512539

This paper proposes a pseudo 2D string matching (P2SM) technique for high efficiency screen content coding (SCC). The technique uses a primary reference buffer (PRB) and a secondary reference buffer (SRB) for string matching and string copying. In the encoder, optimal reference string searching is performed in both PRB and SRB, and either a PRB or an SRB string is selected as an optimal reference string on a string-by-string basis. If no reference string of at least one pixel is founded for a current pixel, then the current pixel is coded as an unmatched pixel. Compared with HM-16.4{+}SCM-4.0 reference software, the proposed P2SM technique achieves up to 37.7% Y BD-rate reduction for a screen snapshot of a spreadsheet. On average, using HEVC SCC common test condition and YUV test sequences in text and graphics with motion category, the proposed technique achieves Y BD-rate reduction of 7.7%, 5.0%, 2.6% for all intra (AI), random access (RA) and low-delay B (LB) configurations, respectively in lossy coding with both intra block copy (IBC) and P2SM having the same 4 coding tree units (CTUs) searching range, and bit-rate saving of 6.0%, 3.9%, 3.1% for AI, RA, LB configurations, respectively in lossless coding with IBC having full frame searching range while P2SM having only 2 CTUs searching range, at very low additional encoding and decoding complexity.