Research And Design Of Video Streaming Transmission Mechanism Based On Digital Fountain Codes

Because streaming media video communications are no longer limited to dedicated networks, such as cable television networks, digital television networks and so on, more and more video services are hosted on the common IP network, such as Internet TV, video telephony, remote education, remote network supervision and so on. However, due to the network layer of the existing IP networks do not provide reliability guarantees, packet loss is inevitable.Therefore, based on the existing IP network model, scholars have proposed many methods to improve the reliability of the transmission via networks, such as data carousel method, ARQ method and the application layer forward erasure code method. The great delay caused by data carousel method makes it unavailable for streaming media transmission. On account of its inapplicability to multicasting and high latency, ARQ method is not suitable for real-time streaming media transmission. Because of the fixed code rate and larger computational complexity, the traditional erasure codes are not suitable for real-time streaming media. However digital fountain codes as a rate-less codes, have variable code rate and mostly involve only the XOR calculation process which makes it more suitable for streaming media, especially real-time streaming media transmission. This paper studies the digital fountain codes for streaming media transmission mechanism, the main contents are as follows,1. This paper first reviews the main principles of encoding and decoding of several major erasure codes, such as RS codes, Tornado codes, LT codes and Raptor codes. Then this paper points out the shortcomings of these erasure codes when applied to real-time streaming media transmission.2. This paper designed a new degree distribution with the principle of making the encoding packets more effective based on the characteristics of the systematic code. And then simulates performance when applied to the systematic code compared with original robust soliton degree distribution. 3. This paper describes the design process of streaming media transmission mechanism based on digital fountain codes. In the coding end, matching streaming media data flow with the block encoding date structure, the occurrence of pseudo-random numbers and other aspects have been done in the design. In the decoding end, according to the feature of systematic code, a decoding method that combines Gaussian elimination decoding and MP decoding is proposed. Meanwhile, according to three-ends streaming media features, a platform-side assistance method is proposed to improve the reliability of streaming media transmission.4. Based on Gilbert packet loss model, the overall performance of the system has been simulated, the residual loss rate is greatly reduced.