Hybrid Digital And Analog Video Transmission Based On Dynamic Adaptive Streaming Media

Recently,due to the advantages of low cost,high reliability and dynamic adaptability,the dynamic adaptive streaming media based on HTTP protocol,namely DASH,emerged and has developed into a mainstream network video streaming media.The transmission mode is still digital s ignal,and the digital transmission system will have obvious threshold effect and cliff effect.In order to better solve the problem that the receiver with different channel characteristics receives better video quality,HDA,a hybrid digital analog video transmission system,is proposed.Therefore,it is more and more significant to explore the hybrid digital analog video transmission based on dynamic adaptive streaming media.In this paper,we mainly solve two problems: the threshold effect of video quality in DASH system and the matching between transmission rate and channel bandwidth in HDA system,so that HDA video coding technology can be well applied in DASH system.The main work and innovation are as follows:Firstly,a single QP bitrate video transmission scheme based on DASH and HDA is proposed.Under the condition of time-varying channel bandwidth,the scheme only uses a digital basic layer of QP code rate,and adaptively selects different numbers of analog packets according to the estimated bitrate of the channel,and carries out parallel overlay transmission with the digital layer,so as to adapt to the time-varying bandwidth and provide users with a better video experience.In addition,because the influence of data in different frequency bands on the quality of video reconstruction is different,we propose a recombination scheme based on energy aware.First,the importance of all analog packets are sorted,and then the analog packets are reorganized to DASH layers with different transmission priorities.The experimental results show that the PSNR performance of single QP rate scheme is slightly lower than that of traditional dash scheme under the condition of low channel SNR,but with the increase of SNR,the PSNR performance of single QP rate scheme gradually reaches and exceeds that of traditional DASH scheme.Secondly,a multiple QP bitrate video transmission scheme based on DASH and HDA is proposed.On the basis of the single QP bitrate scheme,the digital rate is further stratified to improve the reconstructed video quality of the receiver.In this scheme,the c lient can choose the numbers of the DASH layer according to its own channel conditions,and also can choose the video content of different digital bitrate,which makes the quality of the reconstructed video received by the user further improved.Because analog signal is a kind of interference noise for digital signal in HDA scheme,we propose a scheme of adaptive power allocation between digital and analog,which can provide protection for digital signal and provide as much gain as possible for analog signal.Finally,we propose a retransmission mechanism to solve the problem that the client cannot decode the video in extreme channel conditions.The experimental results show that under the same channel condition,the multi QP bitrate scheme can achieve better reconstructed video quality than the single QP bitrate scheme and the traditional DASH scheme.