Self-adaptive bitstream switching method and system based on cache underflow probability estimation

Abstract

The invention provides a self-adaptive bitstream switching method and system based on cache underflow probability estimation. The method includes the steps of 101) estimating a mean valve of video segment downloading time of each bitstream and a variance of the video segment downloading time of each bitstream at the current network conditions, 102) modeling arrival and departure of video data in a client cache into an Ek / D / 1 / N queuing model, setting parameters of the queuing model according to the mean values and the variances, and for each bitstream, utilizing the queuing model with the determined parameters to calculate the probability that cache queues are empty so as to obtain the underflow probability of each bitstream, 103) setting the underflow risk gain or loss of the current bitstream and the quality gain of each bitstream, and calculating comprehensive profit values according to the underflow risk gain or loss of the current bitstream, the quality gain of each bitsteam and the underflow probability of each bitstream when switching is performed between the bitstreams, and 104) selecting the bitstream with the highest comprehensive profit value to be switched , wherein video segments are obtained through equal duration division of copies of the bitstreams.

Description

technical field [0001] The invention relates to an online streaming media service and an adaptive code stream switching algorithm, in particular to an adaptive code stream switching method and system based on buffer underflow probability estimation. Background technique [0002] In recent years, multimedia services have grown rapidly on the Internet. However, due to the Internet's "best effort" service characteristics, the quality of online video viewing cannot be guaranteed. The best effort: the Internet does not provide any bandwidth, delay and packet loss rate. Assure. However, the end-to-end available bandwidth always fluctuates with the change of the network state, and the self-similarity of network traffic proves that the fluctuation exists widely in a multi-scale range. Small-scale bandwidth fluctuations (on the order of RTT, hundreds of milliseconds to several seconds) can be compensated by introducing increased buffer delay or adaptive media playback technology (Ad...

AI Technical Summary

Problems solved by technology

However, most of the algorithms involved in the code stream switching method in the above scheme adopt heuristic design, and the heuristic refers to the method of designing based on past experience, such as directly setting the bandwidth threshold, and switching the code stream when it exceeds this value, otherwise No switching; there is no mathematical theory support for this, and there is a lack of comprehensive analysis of the cache queue and fragment arrival rate, so it is impossible to calculate the underflow probability of video fragments downloaded by the client cache at each bit rate, resulting in the algorithm The accuracy and reliability of the

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