A new methodology for implementing interactive operations of MPEG-2 compressed video

We present an efficient approach for supporting interactive operations such as fast forward (FF) and fast rewind (FR) in MPEG-based interactive video on demand (IVoD) system. This approach is based on transmitting additional data of the same movie from the server to the digital storage device (DSD) at a client station. The special additional data consists of an elementary stream (ES) which has all I frames. The “interactive” data is generated from the storage at the server every n-th frame from the original MPEG-2 compressed video. During the appropriate procedure, the server can perform the FF/FR data in a group of pictures (GoP) structure in an independent fashion. Fast forward and fast rewind operations are supported using as much or a little more network bandwidth than is already allocated for normal playback. Assuming that the decoder consumes data at the constant rate of normal playback and the data is transferred over the network with the average bit rate, then the number of supported speedups we can achieve depends on the GoP lengths (N) and the recording ratio during normal play