A reordering device 1.sub.-- 1 rearranges the segments of each block of time series data comprised of a plurality of blocks in block units. A selecting device 2.sub.-- 1 selects from among a plurality of time series data S1.sub.-- 1 to 1.sub.-- 4 rearranged by the reordering device 1 by switching in accordance with the speed and transmits the corresponding segments of the selected time series data sequentially to the reordering device 3.sub.-- 1 etc. as the streams S2.sub.-- 1 etc. The repeat reordering device 3.sub.-- 1 rearranges the segments contained in the stream S2.sub.-- 1 in units of blocks so as to restore the original order and transmits this rearranged time series data.

A media-on-demand system employs predictive memory caching for a media server and associated data storage device to meet requests from multiple clients for media programs stored on the data storage device. The system allocates a plurality of sections of the server memory buffer to accomodate requests for popular titles. When requests for a title are received from a first grouping of clients, the server scheduler establishes a first streaming data process for the requested media program by reading in the data blocks for the program and retaining the data blocks in memory for use by another group of clients if requested close enough in time to the first grouping such that the first data block of the media program is still retained in memory. Used data blocks are removed if no requests by another group of clients are made within a given time and the memory is full or if the title is of a low priority level. The data blocks for the requested media program are accessed from data storage only once and retained in the server memory buffer until all groups in the time period have been serviced, thereby allowing multiple requests for popular titles during Prime Time to be handled with a minimum of accesses to the data storage device and with a minimum of server hardware requirements and costs.

A computer process which requests streams of motion video titles and decodes and displays the motion video signals of the stream for display in a computer display device is constructed in the form of an applet of a multimedia document viewer such as a World Wide Web browser. Accordingly, a designer of multimedia documents such as HTML pages can easily incorporate motion video titles into such HTML pages by specifying a few parameters of a desired title or a desired portion of a title to be requested from a video server. The applet builds bit stream control signals from the specification of the title or the portion of the title. The bit stream control signals request transmission of the title or the portion of the title from a bit stream server such as a video server and are in a form appropriate for processing by the bit stream server. The applet transmits the bit stream control signals to the bit stream server to thereby request that the bit stream server initiate transmission of a bit stream representing the requested title or the requested portion of the title. The applet also builds decoder control signals from the specification of the title or the portion of the title. The decoder control signals direct a bit stream decoder to receive the requested bit stream from the bit stream server and to decode a motion video signal from the bit stream. The applet transmits the decoder control signals to the decoder to cause the decoder to receive the bit stream and to decode the motion video signal from the bit stream.

A Video-On-Demand (VOD) scheduler maintains a queue of pending performance for at least one movie and determines a maximum wait tolerance time for a longest waiting one of the pending performance requests. When stream capacities become available, rather than scheduling the movie immediately the scheduler delays performance of the video until just prior to expiration of the maximum wait tolerance time of the longest waiting one of the pending performance requests. In the interim, additional streams can join queue. When the performance occurs all performance requests on the queue are served from the a single stream provided from the assigned stream capacity.

The rate staggering technique for efficient storage and retrieval of video data is embodied in a data processing system including a disk array based video server, which includes a disk array for storing video data, a processor for processing data, a memory buffer for storing video data and a rate staggering controller. Data is transferred to a network from video server through a network interface and from the network to client stations employing devices having differing resolution capabilities. The processor executes tasks under control of the rate staggering controller. These tasks include a retrieval task which retrieves scalable video from the array of disks, a storage task which stores videos temporarily in the memory buffer, and a transmission task which transmits video to client stations through the network.