The Development On The System Of Vedio Meetings Based On IP Network

With the development of Internet and the improvement of multimedia communication, it is more concerned to have a video meeting based on the IP network. Especially, the development of LAN/WAN and the improvement of PC provide the platform of hardware for practicability of video meeting. Therefore the video meeting based on IP network will become the mainstream.This dissertation analyses the characters of video meeting based on the IP network and the architecture of network and the designing technonic of video meeting system. A coder/decoder of highly compressed frame rate based on H.263 is researched and carried out to meet the real-time and narrow band requirement. On the base of the fast coding algorithm (fast DCT, fast motion estimation), a resolve method, all zero DCT coefficient prediction and the MMX computation, is proposed, which is combining two kinds of projects and improving the coding speed. On the premise of the quality of the image, it is up to 300 times of video compressed rate, while the speed of coding and decoding is above 30 frames per second. Secondly, under the main framework of the system, it can meet the requirement of point to point or point to multipoint based on extendable translate mode of RTP/RTCP and Multicast. Using this mode, running well of the vedio meeting and acception of the service quality system is promised, according to the dynamical media stream of the channel. A avoid block algorithm based on FLC is adopted to resolve the block problem caused by stream media. The status of network is adjusted and the meeting is going well by using the block control algorithm based on the RTT. At last, the scheme of tunnel penetration is adopted and the client soft is economized. The technical problem of penetrating fireproof wall and the installing problem of the scheme of tunnel penetration are solved by using the principle of port mapping. Some key technologies about the multimedia communication based on the IP network are covered in this dissertation and the results have been applied in practical projects.