Ip Network Video Transmission-based Anti-loss Technology Research

With the phenomenal growth of communications and multimedia applications, the interest in video communications is increasing rapidly. Because of its ubiquity, the Internet has been envisioned as the future platform for carrying various video services. However, because the Internet is a best effort network that does not guarantee lossless nor timely delivery, error control in video communication over the Internet is a challenging research field. For effective video communications, reduction of raw video data, rates is one of the necessary steps. Another equally important task is how to handle errors and losses in a communication network. Video communication over IP networks is often impaired by packet losses. Fortunately, the new video coding standard H.264 proposed by ITU-T provides enhanced video compression performance and the better performance of error resilience. H.264 introduces an IP packet oriented coding mechanism that is of great benefit to video transmissions over packet switched networks. As compared to previous standard, H.264 gives more special consideration to the performance when using IP networks. So H.264 is fit to being used in video transmission over IP networks.This paper deals with the technique of packet loss resilience for H.264 video communication. Firstly, we discuss the FMO (flexible macro-black order) model and frame segmentation methods in the packet loss environment. And we summarize the error conceal techniques that may be used at decoder. Secondly, a new FMO model is introduced: one frame can be rearranged to two Network Abstraction Layer (NAL) units by its macro-block type. One NAL unit is background slice; the other unit is foreground slice. When the background slice is lost, we only use the background message in previous frame to conceal the lost macro-block. When the foreground slice is lost, we use whole previous frame to conceal the current frame. So we can improve the quality of reconstructed frame at decoder and the efficiency of error concealment. As compared to other several FMO and error concealment models, the performance of new model is validated in our simulation test. The new FMO model can be used in real-time video conversation applications that are considered the most demanding in the delay requirement among different types of video communications.