Research And Application About Moving Estimating And Compensation In IP Multicast Video Meeting System

Movement estimation and compensation technology is one of important components in video compression technology. Because the performance of movement estimation and compensation technology is directly related to the efficiency of video compression encoding and the quality of image, the movement estimation and compensation technology becomes the hot point and difficulty of research in video processing field. Since video conferrence system is characteristic of low cost and high efficiency, it has widespread value in use. To apply the variable block movement estimation and compensation technology for video comferrence system, the main research content and innovation of the paper are as follows:1. Analyze and sum up some technology index and the efficiency of some typical fixed block search matching algorithm of traditional fixed block movement estimation technology.2. Aim at the problem of search matching template in variable block movement estimation, based on the analysis of fixed block search matching algorithm, analyze seven kinds division mode of the macroblock and subblock which is formulated in H.264 video encoding standard. According to the differences of the type of macroblock, the shape of subblock and characteristics of video sequence(the correlation of the time and space of video sequence,the center-biased characteristics of the motion vecter,the horizontal and vertical distribution character of the motion vecter),select traditional hexagon search matching template and make some improvement which meets the horizontal and vertical distribution character of the motion vecter and the search matching demand about the square subblock, the vertical rectangular subblock and horizontal rectangular subblock in H.264 video encoding annotation.3. Aim at the division problem of the macroblock and subblock in variable block motion estimation,put forward the division strategy of the macroblock and subblock which is based on the calculation and judgement of the subblock motion vecter. First, calculate the motion vecter of each subblock. Second, by comparison with the type of motion vecter, determine the motion circumstances of adjacent subblock and divide and combine the macroblock and subblock. The result is to realise the division of the macroblock and subblock in variable block motion estimation reasonably.4. Make research about the IP multicast technology and DirectShow technology. By using DirectShow technology, realize the variable block motion estimation algorithm based on H.264 video encoding standard put forward in the paper. By applying IP multicast technology, finish the transmission of the video and radio data among some nodes. Last, realize the pure software video conference system which is at low cost, high efficiency and suitable to LAN. It has good performance in campus LAN.