In order to improve the security and efficiency of video image encryption and to improve the speed of video image encryption,in this study a composite Lorenz-Duffing high-dimensional chaotic system was constructed,and the nonlinear dynamic characteristics of this composite chaotic system were analyzed by using phase diagram and time-domain response diagram,then a video image encryption algorithm was proposed based on this new compound chaotic system。Firstly,the video is preprocessed and converted into an image in BMP format。Secondly,the image...