Adaptive Video Dual Domain Watermarking Scheme Based on PHT Moment and Optimized Spread Transform Dither Modulation

To address the challenges of video copyright protection and ensure the perfect recovery of original video,we propose a dual-domain watermarking scheme for digital video,inspired by Robust Reversible Watermarking(RRW)technology used in digital images.Our approach introduces a parameter optimization strategy that incre-mentally adjusts scheme parameters through attack simulation fitting,allowing for adaptive tuning of experimental parameters.In this scheme,the low-frequency Polar Harmonic Transform(PHT)moment is utilized as the embedding domain for robust watermarking,enhancing stability against simulation attacks while implementing the parameter optimization strategy.Through extensive attack simulations across various digital videos,we identify the optimal low-frequency PHT moment using adaptive normalization.Subsequently,the embedding parameters for robust watermarking are adaptively adjusted to maximize robustness.To address computational efficiency and practical requirements,the unnormalized high-frequency PHT moment is selected as the embedding domain for reversible watermarking.We optimize the traditional single-stage extended transform dithering modulation(STDM)to facilitate multi-stage embedding in the dual-domain watermarking process.In practice,the video embedded with a robust watermark serves as the candidate video.This candidate video undergoes simulation according to the parameter optimization strategy to balance robustness and embedding capacity,with adaptive determination of embedding strength.The reversible watermarking is formed by combining errors and other information,utilizing recursive coding technology to ensure reversibility without attacks.Comprehensive analyses of multiple performance indicators demonstrate that our scheme exhibits strong robustness against Common Signal Processing(CSP)and Geometric Deformation(GD)attacks,outperforming other advanced video watermarking algorithms under similar conditions of invisibility,reversibility,and embedding capacity.This underscores the effectiveness and feasibility of our attack simulation fitting strategy.

Unequal Forced-Intra-Refresh for robust video streaming

For video streaming over lossy channels, intra refresh can mitigate the error-propagation effect caused by packet losses Besides some intra-mode macroblocks （MBs） generated by the ＂Lagrangian rate-distortion＂ or ＂Sum of absolute difference＂ mode decision, the encoder or transcoder possibly needs to increase some ＂forced＂ intra-mode MBs for robust video streaming. Based on the error-propagation analysis in a group of pictures （GOP）, we propose an unequal Forced-Intra-Refresh （FIR） scheme to improve packet loss resilience of video streaming. According to a GOP-level error-propagation model, the proposed unequal FIR scheme can optimally increase the unequal number of forced intra-mode MBs for different frames in a GOP. Simulation results showed that the proposed scheme can effectively enhance the robustness of video streaming under different channel conditions, and achieve about 0. 1-0.9 dB gains over the average FIR scheme in H.264/AVC tools.

GOP-Level Bit Allocation Using Reverse Dynamic Programming

An efficient adaptive group of pictures （GOP）-Ievel bit allocation algorithm was developed based on reverse dynamic programming （RDP）. The algorithm gives the initial delay and sequence distortion curve with just one iteration of the algorithm. A simple GOP-level rate and distortion model was then developed for two-level constant quality rate control. The initial delay values and the corresponding optimal GOP-level bit allocation scheme can be obtained for video streaming along with the proper initial delay for various distortion tolerance levels. Simulations show that the algorithm provides an efficient solution for delay and buffer constrained GOP-level rate control for video streaming.