Research And Realization Of Congestion Control And Fault Tolerance Technology In Video Transmission

The survey of network real-time video stream transmission and control is a hot issue. With the development and popularization of Internet, video is widely applied in network. Transmission of real-time video has much large data, it requires wider network bandwidth and lower delay. However, the current Internet can not offer Quality of Service (QoS) guarantee to real-time traffic, it makes real-time video over the Internet face many difficulties. Therefore, it has become a big challenge to researches both in theory and practice how to provide efficient, fair and optimal streaming video over the Internet.Based on the research of the video compression standards, the transport protocols over IP network and the current congestion controls of real-time video both in network and end system, this paper presents a new control algorithm to real-time video stream transmission, namely End-based Network-adaptive Rate Control approach (ENRC), The simulation test shows that the proposed algorithm has better adaptability and TCP-friendliness. To be specific, the main endeavor and contributions of the paper are as follows:1. We have encapsulated additional header information to UDP datagrams. Not only does it make UDP protocol information enrich, but also the data is recombined according to sequence number and guaranteed unpacking correctly.2. ENRC operates on top of UDP, employs Additive Increase Multiplicative Decrease (AIMD) and adapts the sending rate by properly adjusting the inter-packet-gap (IPG). The selection of AIMD parameters and IPG adjustments reduce the magnitude of AIMD oscillation and allow for smooth transmission patterns, while TCP-friendliness is maintained. The results show that ENRC eventually achieves remarkable performance on real-time video delivery and is optimized for unicast video streaming applications. 3. Combined with layered coding, a new mechanism of ENRC and layered coding combination is proposed. Not only does the mechanism guarantee relatively high smooth transmission speed, but also it prevents that awkward network conditions impair the perceptual video quality. In addition, this paper systematically analyses error control in video transmission and elaborates these error control technology combination applications in the present video code international standards.This paper has not only theoretically deeply studied on the video stream transmission, but also presents a new control algorithm based on the current network. The experiment results prove that this algorithm eventually achieves remarkable performance on real-time video delivery.