Fast Coding-Mode Selection and CU-Depth Prediction Algorithm Based on Text-Block Recognition for Screen Content Coding

Mengmeng ZHANG  Ang ZHU  Zhi LIU  

IEICE TRANSACTIONS on Information and Systems   Vol.E99-D   No.10   pp.2651-2655
Publication Date: 2016/10/01
Publicized: 2016/07/12
Online ISSN: 1745-1361
DOI: 10.1587/transinf.2016EDL8031
Type of Manuscript: LETTER
Category: Image Processing and Video Processing
screen content coding,  text-block recognition,  fast algorithm,  coding-mode selection,  depth prediction,  

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As an important extension of high-efficiency video coding (HEVC), screen content coding (SCC) includes various new coding modes, such as Intra Block Copy (IBC), Palette-based coding (Palette), and Adaptive Color Transform (ACT). These new tools have improved screen content encoding performance. This paper proposed a novel and fast algorithm by classifying Code Units (CUs) as text CUs or non-text CUs. For text CUs, the Intra mode was skipped in the compression process, whereas for non-text CUs, the IBC mode was skipped. The current CU depth range was then predicted according to its adjacent left CU depth level. Compared with the reference software HM16.7+SCM5.4, the proposed algorithm reduced encoding time by 23% on average and achieved an approximate 0.44% increase in Bjøntegaard delta bit rate and a negligible peak signal-to-noise ratio loss.