Research And Implementation Of Adaptive Video Transmission System Based On Fountain Code

With the development of multimedia technology,video streams account for the vast majority of Internet traffic.Packet loss is a common problem in video transmission,which may lead to decoding errors and affect the viewing experience of users.Forward error correction can effectively solve the problem of packet loss,adopt error-tolerant coding for the source data,generate redundant data,and when packet loss occurs,the lost data packet can be recovered with a relatively low delay.Fountain code,as a forward error correction technology,has the advantages of no code rate,no feedback,low encoding and decoding complexity,etc.The application of fountain code technology in video transmission system can improve the packet loss problem in the transmission process and improve video transmission quality.This thesis studies the principle of system Raptor encoding and decoding.According to the requirements of real-time video transmission,we select the appropriate encoding parameters and design the corresponding video data packet structure.When the fountain code is used as channel encoding,if a fixed encoding redundancy is set,it is similar to a fixed code rate coding cannot adapt to different network conditions.The decoding overhead of the system Raptor code is studied,and the coding redundancy is adaptively adjusted according to the historical packet loss of the channel.At the same time,the packet loss information can also be largely in order to reflect the available bandwidth of the channel,this thesis also dynamically adjusts the sending bit rate of the sender according to the packet loss information to further improve the video quality of the receiver.In order to further verify the algorithm,OK3399-C is selected as the embedded platform,and a real-time video transmission system is built on this platform.The fountain code is applied to the system,and the adaptive transmission strategy of video is tested under different packet loss rates.The test results show that when packet loss occurs,the scheme involved in this thesis can balance the relationship between decoding success rate and decoding overhead with less redundancy,improve bandwidth utilization,and achieve smooth playback of video.