Video time-shifting apparatus

Abstract

A video time-shifting system characterized in having a continuous recording track accessed by separate, asychronous read and write facilities enables playback of a video program to commence from any point in the program while continuing to be recorded in real time, thus providing VCR-like program control features such as PAUSE/RESUME, REWIND, and FAST FORWARD. A memory is used to store information relating to various points in the program so that even upon receipt of multiple PAUSE commands, the system automatically keeps track of correct program re-entry. In the preferred embodiment, the storage means takes the form of a continuous recording track in a magnetic disk drive. To prevent discontinuities associated with the recording and reproducing of material representative of the video program, the system preferably incorporates a plurality of write heads, each associated with a different recording track, and the system automatically switches from one write head to another so as to effectively link the different recording tracks into a single, continuous recording track. Although program information may be stored in analog form, digital storage is used in the preferred embodiment along with data compression to increase recording capacity. The system preferably further includes a video display generator to output for viewing on the display device visual indicia relating to the program and, additionally, symbols relating to one or more points in the program and/or the time-shifted version thereof.