| with the rapid development of the internet and video coding technology, the video technology applications in the network has also got a great promotion, producing such as online video teaching, video monitoring and many other online video services. The emergency and application of video online teaching make human teaching method under enormous changed. In order to achieve good results, because of the huge amount of online video teaching data, there must have a good system architecture and efficient encoding as a support to ensure the quality of teaching,considering the current network transmission environment. The Video coding standard H.264 offers a high video coding efficiency and network adaptability than the previous standard. Meanwhile, in order to adapt to different transmission environments,H.264 make a revolutionary innovation in the design concept forming two layers:video coding layer and network abstraction lay as separate the video coding and transmission. VCL layer mainly provides the core high-quality video encoding, NAL layer encapsulate the VCL layer encoded stream into NAL unit sequence.This paper applicates the H.264 video encoding technology to the video network teaching system.By studying the coding characteristics and the coding framework of the H.264,i design and implement a video network teaching system base on H.264. This system uses the C/S mode, in the teaching side the realtime video data will be captured and encoded, then the encoded stream will be encapsulated into RTP protocol packets then transmitted to the student side through the network. In the student side, the received packets will be decoded and displayed, at the same time the feedback information will be transmitted to the teaching side through RTCP. The teaching side adaptive network conditions to ensure the reliability of video transmission accoding to this information. In additon to the application of the advanced video coding standards, this system make bold experiments and improvement to the existing key video coding optimization techniques, including the encoding of NAL layer package. This paper propose the RTP packing algorithm.In order to archive the adaptive congestion control of the video transmission and guarantee the QoS of the video transmission, an improved AIMD model algorithm is taken in this video transmission scheme. |
