Variable-delay video recorder

Apparatus for recording a video signal and for playing back the recorded video signal independently of the continued recording thereof, comprising:

• analog-to-digital converter means for continuously converting an analog video signal to a continuous series of digital samples thereof;
• means for dividing said continuous series of digital samples of said video signal into sequential blocks;
• addressable means for storing said blocks of digital samples of the analog video signal, said means for storing being responsive to addressing control signals, whereby said blocks of digital samples are stored at locations in said means for storing which are identified by addresses, wherein said locations at which sequential blocks are stored need not be physically continuous to one another and wherein aid blocks may be retrieved from said locations responsive to signals including said addresses;
• control means for maintaining a list of addresses corresponding to said locations in said means for storing at which said blocks of digital samples are stored, such that in response to a user command, said list of addresses can be employed to retrieve the blocks of digital samples from the means for storing in the original sequence in which the video signal was converted by the analog-to-digital converter means to said series of digital samples;
• and
• digital-to-analog converter means for converting the series of digital samples retrieved from the means for storing into an analog video signal suitable for driving a video display;
• wherein said control means is responsive to user commands such that storing of blocks of samples may proceed continuously and independently of retrieval of previously stored blocks of samples, and wherein a variable delay between storage and retrieval is provided, said variable delay being controllable by a user.

An apparatus for allowing simultaneous playback and recording of a video program, comprising:

• three essentially identical videotape recording and playback machines, being separately controllable for recording, rewind and playback of sequential segments of the video program on portions of up to three separate tapes;
• a microprocessor, adapted to respond to user commands and to separately control said three identical machines;
• and
• user control means for permitting the user to provide user commands to said microprocessor for control of said three machines;
• wherein said microprocessor comprises means for maintaining information indicative of the sequence of said sequential segments of the program stored on different portions of said up to three tapes, whereby said microprocessor can reassemble said segments into their original sequence for playback in response to a single user command.

A method for recording and playing back a video signal corresponding to a program, whereby a viewer may play back a previously recorded sequential segment of said program while recording of subsequent sequential segments of said program continues, comprises the steps of:

• continuously converting said video signal to a converted form suitable for storage on a storage medium;
• continuously storing segments of said converted signal corresponding to one or more sequential segments of said program on one or more storage media, while maintaining a record of the locations on said storage media at which the segments of the converted signal are stored, and a record of their order in said program;
• reconstituting and playing back the stored segments of the converted signal in their order in said program responsive to viewer commands;
• wherein said step of reconstituting and playing back is performed responsive to viewer commands and independently of said steps of converting and storing, whereby a variable delay controllable by the viewer is provided between the time of storing and the time of playback of particular portions of said program.