Research, Based On The H.323 Video Conferencing Systems

The video conference system is divided into the hardware video conference system and the software video conference system,among them the software video conference system because of its lower cost and strongly mutual communication, abundant function and favorable extensible becomes the preferred remote video conference for more and more people.Because software video conference system deliver video-audio information based on IP network which is a best effort network and doesn't provide quality assurance, so in comparison with hardware video conference system also exist a lot of problem.Therefore there is urgent need of researching the vedio conference system and development of more credibility and valid of video conference system.Some existing video conference standards and the related key techniques are analysed and researched in this paper.This paper aimed at one of the key technique of video conference-the video-audio compression technique carried on more thorough of study and put forward a solution of multi-channel video display of multi-point video conference system.The main contents firstly introduce the general situation,the current development conditions of video conference system and the related standards which include H.323 protocol and H.264 protocol;then detailed introduce the new fast mode selection algorithm for intra-prediction in H.264 which put forward by this paper.The selection algorithm for intra-prediction of H.264/AVC is analyzed and improved based on the PAN's algorithm, which compute the direction of the edge by sub-sample method and decide prediction mode by computing the amplitude of the edge vector and an early termination mechanism is proposed for the mode selection of Intra₄x4 on certain condition. Experimental results show that the proposed algorithm can reduce the coding time and encoder complexity while maintaining similar PSNR and bite rate ;Finally,this paper proposed the design and realization of multi-channel display in multi-point video conference system based on certain domestic video conference manufacturer.In the end of this paper, some extensible problems in next step are discussed and give some suggestion.