Extra Sign Bit Hiding Algorithm Based on Recovery of Transform Coefficients

This paper focuses on applying a new sign bit hiding method to improve the video coding efficiency. Sign bits account for a large proportion of the encoded stream conforming to the latest high efficiency video coding (HEVC) standard; hence, its hiding technique is of great significance. In this paper, an extra sign bit hiding algorithm is proposed. The parity of the sum of the first and last nonzero coefficients in a coefficient group is used to predict the sign bit, and one more bit could be hidden at the coefficient group level based on state-of-the-art algorithms. The proposed algorithm could recover transform coefficients with minor adjustment on multiple sign bit hiding technique in HEVC. Evaluation results on standard test sequences demonstrate -0.06\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$-\,0.06$$\end{document}% BD-rate gain compared to well-known multiple sign bit hiding method. Besides, either the quality loss or complexity increase is negligible with the proposed algorithm, which is applicable in real-time processing.