Research On Packet Loss Resilience For MPEG-4 Video Conferencing

With the development of network, video conferencing system is much closed to people's everyday life. Especially it can change the way we used to attend meetings with long trips. It saves time and money. And as the IP based network is more and more widely used, the video conferencing over IP based network becomes the key technology in video conferencing application.According to the video conferencing system, video encoding and decoding definitely is the key issues by which the quality of the reconstructed video is affected. But in the IP based network, besides the video encoding technology, the packet loss also seriously influences the quality of reconstructed pictures. The aim of this paper is to make the research on packet loss resilience.At the beginning, existing packet loss resilience technologies in IP based network are widely investigatedspecially the erasure codes, RS code and Tornado code are deeply studied. Tornado code is selected and used in our designed video conferencing system. In the system audio and video transmitted are jointly protected, at the same time, an end-to-end feedback congestion control scheme based on RTP/RTCP is used, finally the experiments of the scheme are made. The results of experiments show that proposed scheme not only decreases the packet loss ratio, but also efficiently utilizes network bandwidth, therefore the quality of the reconstructed video are raised.