Study Of The Digital Watermarking Technology For Video

With the development of multimedia and computer technology,people create and use digital media product more easily,and the development of Internet promotes the wide-spread of multimedia information.However,because the digital products can be copied without any degradation in quality,illegal users can easily access,duplicate and spread them,which heavily damaged the copyright owner's economic interest.So security of multimedia information becomes an important issue.Digital Watermarking technology can embed copyright information into original data without any effects on use of the data,and the watermark can't be removed,only special extracting algorithm can extract it. So digital watermarking as an effective method of copyright protection becomes an exciting research field,especially hot the video digital watermarking.In this paper,video watermarking techniques are introduced,including their development and general method.The relative merits of data encryption and digital watermarking in copyright protection is analyzed:encryption only secure the data in encrypted state,once deciphered,the data can be copied and tampered randomly;digital watermarking can not stop the duplicating and transmitting,but it can trace the illegal users;Combined the MPEG-4 multimedia data compression standard,this paper proposes an approach for protecting the copyright of MPEG-4 video-CPEW(Copyright Protection based on Encryption and Watermarking),which bases on the encryption algorithm and digital watermarking.Considering the relative merits of data encryption and digital watermarking in copyright protection,the characteristic of MPEG-4 CODEC,the merits of DCT Transform,combined with the merits of encryption and watermarking,this approach only encrypts some parts of the picture data in frequency domain to ensure the security of video transmission,and embeds the copyright information using Spread Spectrum watermarking in intra-coded frames to protect the copyright of MPEG video.Experimental results indicated the encryption algorithm of CPEW secured the video effectively;the watermarking algorithm of CPEW is robust for MPEG compression,noising,filtering.This approach has abroad application value in network video transmission.