The Application Study Of Frame Dropping Algorithm Based MPEG-4 Stream Media System

This paper performed a detailed study on frame dropping based MPEG-4 stream media system. While terminal be IP set-top box stream media system, network bandwidth and client buffer are both constrained. In this paper corresponding video smooth technologies are studied.After in-depth study of characteristic of stream media system, while traditional video smooth technologies only taking bandwidth or buffer limit into account, a creative server based frame dropping algorithm is presented in this paper, therefore a QoS awared MPEG-4 based multimedia stream services system model is implemented.Through detailed mathematic analysis and induction, a discrete time model of bandwidth and buffer limited stream media system is built. And corresponding greedy algorithm method is used to transport video data. By detailed mathematic computation, it is approved that greedy transport algorithm can be used to verify the feasible of a frame subset.Based on greedy transport algorithm, a server based least frame dropping algorithm is presented to select the frame to drop according to video transport characteristic and resource condition. By recursive computation, the server compute the maximum data frame sub-set possible for transport. And detailed analysis and computation of algorithm procedure ensures least frame is dropped and maximum video data is transported.With the characteristic of MPEG-4 video transport, improvement had made to least frame dropping algorithm and backwards search optimal frame dropping frame is present. This algorithm taking neighbor frame state into account, plus frame specific information corresponding cost function, utilized shortest path first algorithm, computing the optimal frame sub-set. The algorithm is approved to be optimal while complicated and involves huge computation. Therefore a serious of least frame based intelligent frame dropping algorithm are introduced, including real time algorithm, frame distance based algorithm, minimum cost algorithm and best ratio based algorithm. This kinds of algorithm introduced different cost function as judge factor in frame dropping, therefore afford excellent performance while reducing computation request hugely. Detailed studies show that best ratio based algorithm has best general performance.Best ratio algorithm is integrated into MPEG-4 DMIF and the results show improved service quality of client and a brilliant application foreground is obvious.