Method and apparatus for reproduction of video signals from magnetic tape at a tape transport speed differing from that of recording

Apparatus for controlling reproduction of video signals from a magnetic tape at a tape transport speed different from the recording speed, comprising:

• a picture memory with a capacity of at least one picture field for storage of picture information;
• an administrative memory (4) for storing age information of respective blocks of picture information stored in said picture memory and having storage locations corresponding to addresses to said respective blocks, said administrative memory also having means (5) for decrementing the content of any said storage location when said location is addressed;
• a block identification counter (2) for counting through the block addresses of the administrative memory (4);
• a memory duration controller (8) for controlling the block identification counter (2) and said administrative memory (4), said controller including means for supplying an age limit word to said administrative memory for each new block identification accompanying said blocks of picture information, means for activating said counter after receiving each new block identification and causing it thereafter to successively address the locations of said administrative memory and connect the decremented content values of said locations for replacement of the previous contents ,and means for recognizing interruptions of the rhythm of succession of block identifications;
• a buffer memory (9) having an input register (7) responsive to zero content location outputs of said administrative memory for being loaded with the corresponding location addresses, for storage of successive identifications of the block addresses for which the storage time has been counted out to a said zero content output in said administrative memory (4), said buffer memory (9) being connected for loading from its said input register under control of said memory duration controller;
• an erasing value signal generator (6) for blockwise generation of erasing value signals and overwriting in the picture memory of picture information belonging to block addresses stored in said buffer memory (9), and
• said memory duration controller (8) also having means responsive to recognition of said rhythm interruption for controlling the transmission path (10) of said erasing value generator (6) to said picture memory (11).