Research And Implementation Of Low Bit Rate Image Coding Technology In Mobile Environment

With the development of 3G communications and image coding technology, wireless video transmission is widely used in a mobile environment. The available bandwidth of the wireless network to transfer data in the mobile environment is limited, so a higher demand on quality of service is required.At first, this paper introduces the necessity of image low bit rate coding for wireless video transmission, background and significance of the subject, the status of low bit rate image coding technology, the history and development of image coding techniques.Then, this paper describes key technologies of the current image coding techniques, including transform, quantization and entropy coding and predictive coding, motion estimation and motion compensation. On this basis, the H.264/AVC image encoding standard’s application scope, technology, innovation and principle of the wavelet compression are also described.This paper analyzes the characteristics of image codec for the mobile environment, according to its characteristics, we researched the video object motion estimation based on H.264, implement a related experiment to verify that the motion estimation method can effectively reduce bit rate. To transmit video in wireless environment, the paper analyzes two kinds of wireless video transmission in mobile environments, they are wireless video transmission based on wavelet and H.264 encoding separately. The application features of wavelet coding and H.264 encoding are also described.Finally, we complete a combined explosive car wireless video transmission system. The system contains three servers, includes registration server, load server and streaming media server. In the terminal part, image coding chip code H.264 image and transfer it to the client player via streaming media server. The critical control parameters and vehicle GPS information of the truck is transport by the communication device to the load server, by using the DTU technology pass through the TCP connection. In the server part, because users often operate database, the terminal only write to the database, the database schema is optimized to improve response efficiency and user experience. In the client part, we completed real-time monitoring, electronic fencing function, and achieve a vehicle management system based on B/S stucture.