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Low-Complexity Watermarking into SAO Offsets for HEVC Videos
Xiangjian Wu,Hyun-Ho Jo,Donggyu Sim 대한전자공학회 2016 IEIE Transactions on Smart Processing & Computing Vol.5 No.4
This paper proposes a new watermarking algorithm to embed watermarks in thr process of sample adaptive offsets (SAO) for high efficiency video coding (HEVC) compressed videos. The proposed method embeds two-bit watermark into the SAO offsets for each coding tree unit (CTU). To minimize visual quality degradation caused by embedding watermark, watermark bits are embedded into SAO offset depending on the SAO types of block. Furthermore, the embedded watermark can be extracted by simply adding four offsets and checking their least significant bits (LSB) at the decoder side. The experimental results show that the proposed method achieves 0.3% BD-rate increase without much visual quality degradation. Two-bit watermark for each CTU is embedded for more bit watermarking. In addition, the proposed method requires negligible computational load for watermark insertion and extraction.
Fast Intra Mode Decision for Screen Contents Coding in HEVC
AHN, Yong-Jo,WU, Xiangjian,SIM, Donggyu,HAN, Woo-Jin 'Institute of Electronics, Information and Communi 2016 IEICE transactions on information and systems Vol.99e.d No.9
<P>In this letter, fast intra mode decision algorithms for HEVC Screen Contents Coding ( SCC) are proposed. HEVC SCC has been developed to efficiently code mixed contents consisting of natural video, graphics, and texts. Comparing to HEVC version 1, the SCC encoding complexity significantly increases due to the newly added intra block copy mode. To reduce the heavy encoding complexity, the evaluation orders of multiple intra modes are rearranged and several early termination schemes based on intermediate coding information are developed. Based on our evaluation, it is found that the proposed method can achieve encoding time reduction of 13 similar to 30% with marginal coding gain or loss, compared with HEVC SCC test model 2.0 in all intra ( AI) case.</P>
Block Level Difference based Scene Change Detection Method
Xiang Li,Yong-Jo Ahn,Xiangjian Wu,Donggyu Sim 대한전자공학회 2015 대한전자공학회 학술대회 Vol.2015 No.11
This paper proposes a scene change detection method based on block level difference of a whole frame. During the detection process, every frame is divided into 64x64 blocks, and the SAD of two corresponding 64x64 blocks from the consecutive two frames will be calculated, then all the 64x64 block SAD values of two consecutive frames will be stored in a predefined matrix. For every two matrices, the difference of every two corresponding SAD elements will be calculated, the decision whether scene change detection exists will be made according to the percentage of the difference values that exceed the predefined threshold. This algorithm has over 95% recall rate and over 96% precision rate by the test of various kinds of video sequences.