Online traffic smoothing for delivery of variable bit rate media streams

Traffic smoothing for delivery of online variable bit rate (VBR) media stre ams is one of the most important problems in designing multimedia systems. Given an available client buffer, a window size, and a window-sliding size, previous window-based online smoothing methods have tried to reduce the pe ak bandwidth allocated in each window. However, as bandwidths allocated in different windows are minimized independently, these methods require a larg e peak bandwidth for transmitting an entire stream. In this paper, a new wi ndow-based method is proposed. It introduces two new ideas, the dynamic win dow-sliding size and the aggressive workahead, for delivery of online VBR m edia streams. Our aggressive and dynamic window sliding (ADWS) method can a utomatically decide on the suitable window-sliding sizes for different wind ows. Thus, the allocated peak bandwidth can be further reduced. By examinin g various media streams, ADWS is shown to be effective and efficient. Consi dering the online transmission of the movie Star Wars with a 90-kB client b uffer, ADWS yields 13% less in peak bandwidth, compared with the best-known window-based online smoothing algorithm SLWIN(1). Its computation cost (th e window-sliding number) is 75% of that required by SLWIN(1).