Research Of Video Coding Algorithms And Realization Of Wireless Video Traffic

With the development of multimedia techniques, people have stronger desire to get versatile multimedia information, and communicate through picture, or video with others. Though the third wireless communication system and IP network have got rapid development, the natural defects of wireless channel lead unstable transmission environment for coded video stream, that is to say, quality of reconstructed video is low. In addition, the resource of hand-held device is limited, coding video using traditional algorithm need consume plenty of system resource, that make video communication become infeasible. Therefore, it is necessary to research on effective video coding algorithm and reliable wireless method to realize wireless video communication.This paper investigates content-based MPER-4 coding standard, presents an algorithm of segmenting moving objects automatically in video sequences. The basic idea is to use the information of the difference of adjacent frames, introducing gradient filtering and background formation technology to initialize object, then to employ distance method to track object. Moreover, the paper puts forward a fast motion estimation algorithm with adjustable predictive quality. Taking advantage of the spatial and temporal correlation of motion vectors, motion estimation of the algorithm is realized by predicting initial search center location, analyzing whether a silent macroblock or not, adjusting windows size, and using progressive block matching measure of adjustable predictive quality, at the same time, introducing adjustable function to add controllability between predictive quality and searching speed. Furthermore, the paper addresses the topic of video transcoding. Two algorithms of fast motion vector re-estimation in spatial and temporal domain respectively are proposed, using existing motion information and direct coefficients of DCT to estimate future motion vector. Experiment results show that above-mentioned three algorithms acquire good coding performance.In this paper, we also study EV-DO system key techniques, such as scheduler algorithm, power control. Simultaneously, we introduce our system design method and system performance.