Research On Digital Watermarking Technology Of MPEG-4 Video Based On DCT

With the fast development of computer technique and Internet, the application of digital media develops every day, and it is playing a more and more important role in copyright protection, content authentication, usage control, etc. The related research is going deeper and deeper. The purpose of this paper is to research digital image and Video digital watermarking technique.The paper firstly discusses the researching background and meaning, and also gives a general summary of current researching condition. Then the paper summarizes the model and algorithm of digital watermarks, and a DCT-based watermarking technique is presented. based on the improvement of the tradithional algorithm. Finally, the paper proposes a real-time application oriented video watermarking algorithm with the stable image watermarking algorithm. The contents of this paper include:1. The paper analyzes current researching condition and summarizes the related knowledge of digital watermarking technique. Furthermore, it analyzes the typical digital watermarking algorithms and its application. These works lay a foundation for this thesis.2.A DCT-based watermarking technique is presented. The prior DCT based watermarking algorithm is enhanced. We divided the pixel blocks to smaller sub-blocks, thus, we can reduce high-order matrix computation to lower order matrix computation, which will improve the speed of watermarking system.Meanwhile,the algorithm also reduce the effect from "visual block".The experimental results demonstrate it is a robust algorithm and has quite ability against attacks.3.This paper presents a real-time application oriented video watermarking algorithm. Based on the DCT algorithm, We presented an algorithm to embed watermarking system into I frames, so there's no need to completely decode the video to embed watermark. This reduced the complexity of watermark computation, and fulfilled the real-time requirement of video watermarking. The cost of the efficiency of this algorithm is that the density of watermark information is reduced, but for those application scenarios which needs to embed watermarks to protect copyright information for large volume of videos with very fast speed, this algorithm will be a good solution.