| The development of network technology and multimedia technology, promote the integration, digitization, intelligentize, individuation of communication technologies. With the rapid popularization of 3G technology, transmission of audio,data and image through wireless network platform are becoming the power of new communication service. Because the network characteristics of wireless channel are very different from wired channel, and mobile terminal differs much from fixed terminal, the research of key network video transmission technology is very important both in theory and in practice.Through analysis of wireless networks transmission environment, low-bit rate video coding technology, rate controlling technology, error controlling technology and energy saving technology are supposed to be the key technology to solve bandwidth fluctuation of wireless transmission environment, high bit-error ratio, low computing power of mobile terminal, low stand-by time.Against the high complexity of classical ratio controlling, a low complexity ratio controlling algorithm based on bit allocation optimization is suggested. First allocate target bit number of frame layer according to the complexity of image, then select the optimal coder according to the complexity and the. Experiment results proved that this arithmetic can made the code rate stable without reduction in video transmission quality.Based on the analysis of low ratio video coding technology, ROI arithmetic is chosen as a research object, image segmentation arithmetic is proposed to be the key technology of ROI arithmetic. In classical image segmentation arithmetic, large amount of preprocessing work are needed to promote the accuracy of segment,which means high operation quantity. A new image segmentation arithmetic based on motion vector cluster analysis are proposed to extract the mobile target as a interested area in a stationary background. This arithmetic applies the intermediate result of video coding arithmetic, need few preprocessing, can be run parallel, and is easy to implement. Furthermore, coding priority for motional area, fine coding based on SPIHT arithmetic, H.264 coding for background and vision insensitive area are realized. It is proved practically that this method can raise the coding and transmission efficiency, improve vision effect.With concerning to the poor effect and low efficiency of segmenting complex texture image under the classical video segmentation algorithm, we adopted the theory of discrete amplitude signal transformation, and established the video segmentation algorithm that based on the analysis of discrete amplitude multi-resolution and the precision of the signal amplitude. The result of the experiment results showed that the algorithm would segment the satellite images and other complex texture images well, and was suitable for achieving high-speed real-time processing hardware. Theory of discrete amplitude signal transformation are employed to establish.Finally, we restudied the error control algorithm, and provided the decoder error detection and error concealment algorithm. It introduced the large visual effect theory, and by Comparing of space adjacent to the macro block, the time the adjacent macro blocks, it could detect the error macro blocks, and use airspace and time-domain hidden method to hide the error. Experiments showed that the algorithm could hide the error and detect error macro block well.Based on various algorithms and simulated experiments, we made further study on hardware accomplishment and algorithm optimization. We employed the hardware function of DSP, FPGA and GPU to improve operation speed, and cut power consumption.
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