Implementation And Optimization Of HD Real-time Video-mixing Communication System Based On H.264

Video communication is a common way of communication in modern communication, widely used for security monitoring, live Internet broad casts, video conference and so on.The video communication has the characteristics of more intuitive and lager information than the text communication and the voice communication. How to efficiently compress the original video by encoding is one of the key technologies in the field of video communication. Nowadays the most widely used video coding standard H.264, and the latest video coding standard H.265 both can compress the original video effectively, wihch can reduce the compressed video bitrates to the most extent. However the complex mathematical calculations of two coding standard s will increase the burden of the computer, slower the real-time encoding. Because mathematical operation is the easy for the embedded system, most common commercial video encoders are developed on the embedded platform. At the same time, another key technolog y is how to mixing multi-video bistreams into one new bitsream in real time. The traditional video-mixing method is to decode the bistreams to the pixels firstly, then mix them on the pixel domain, finally re-encode the one mixing-video. This method is seasily achieved, but it will cost a lot of time and also cause the additional loss of the video quality. So, how to mix the video bitstreams directly without decoding is a research focus of our research field.A fast video-mixing method based on syntax was proposed in paper, which is for H.264 encoding standard. This method can mix four video bitstreams into one new outging bistream in H.264 syntax domain without decoding and re-encoding process, which means that the time of mixing will be remarkably reduced. Meanwhile, an H.264 real-time video communication system will be build in Hi3531 embeded Linux board to test the fast video-mixing method. The main works of this thesis can be presented to the following steps.1. This thesis gives a briefly introduction to the H.264 en coding standards and analyse three open source encoder of H.264. Based on the analysis, this thesis decided to use the Linux embedded board to develop H.264 video communication system.2. Several commonly used video-mixing methods are introduced. A fast video-mixing method baesd on H.264 syntax is proposed and implemented.3. The proposed video-mixing method is tested in both PC and the embedded Linux board. And there is a q uantitative analysis of mothod’s advantages and disadvantages in the thesis. The experimental results show that compared to the traditional pixel domain video-mixing methods, the proposed method can save more than 90% of the time, and r educe the loss of video quality, which proved that this method has a certain practical value in video communication.