Improved intra-block copy and motion search methods for screen content coding

Krishna Rapaka; Chao Pang; Joel Sole; Marta Karczewicz; Bin Li; Jizheng Xu

doi:10.1117/12.2193685

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22 September 2015 Improved intra-block copy and motion search methods for screen content coding

Krishna Rapaka, Chao Pang, Joel Sole, Marta Karczewicz, Bin Li, Jizheng Xu

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Proceedings Volume 9599, Applications of Digital Image Processing XXXVIII; 95991D (2015) https://doi.org/10.1117/12.2193685
Event: SPIE Optical Engineering + Applications, 2015, San Diego, California, United States

Abstract

Screen content video coding extension of HEVC (SCC) is being developed by Joint Collaborative Team on Video Coding (JCT-VC) of ISO/IEC MPEG and ITU-T VCEG. Screen content usually features a mix of camera captured content and a significant proportion of rendered graphics, text, or animation. These two types of content exhibit distinct characteristics requiring different compression scheme to achieve better coding efficiency. This paper presents an efficient block matching schemes for coding screen content to better capture the spatial and temporal characteristics. The proposed schemes are mainly categorized as a) hash based global region block matching for intra block copy b) selective search based local region block matching for inter frame prediction c) hash based global region block matching for inter frame prediction. In the first part, a hash-based full frame block matching algorithm is designed for intra block copy to handle the repeating patterns and large motions when the reference picture constituted already decoded samples of the current picture. In the second part, a selective local area block matching algorithm is designed for inter motion estimation to handle sharp edges, high spatial frequencies and non-monotonic error surface. In the third part, a hash based full frame block matching algorithm is designed for inter motion estimation to handle repeating patterns and large motions across the temporal reference picture. The proposed schemes are compared against HM-13.0+RExt-6.0, which is the state-of-art screen content coding. The first part provides a luma BD-rate gains of -26.6%, -15.6%, -11.4% for AI, RA and LD TGM configurations. The second part provides a luma BD-rate gains of -10.1%, -12.3% for RA and LD TGM configurations. The third part provides a luma BD-rate gains of -12.2%, -11.5% for RA and LD TGM configurations.

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Krishna Rapaka, Chao Pang, Joel Sole, Marta Karczewicz, Bin Li, and Jizheng Xu "Improved intra-block copy and motion search methods for screen content coding", Proc. SPIE 9599, Applications of Digital Image Processing XXXVIII, 95991D (22 September 2015); https://doi.org/10.1117/12.2193685

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