Abstract: A digital processing unit for converting a digital picture signal into data by blocks and for correction encoding a variable-length encoded signal. This digital processing unit includes a digital data compressing section for dividing a picture signal into a plurality of number of blocks, and compressingly outputting digital data of this picture signal based on a processing unit of one or a few blocks, a buffer section for sequentially storing the digital data, and an error correction encoding section for sequentially reading the digital data from this buffer section, and structuring an inner code for each inner block structured by this digital data and structuring an outer code for each predetermined unit of inner blocks, to thereby structure two-dimensional error correction code blocks, to output an error correction code signal.

Abstract: A cassette tape-loading apparatus applied to a magnetic recording and reproducing apparatus using a cassette tape comprises a device for determining the amount of rotation of supply and take-up reels, a device for detecting the rotational direction of the reels, and a device for detecting the amount of tape drawn out of the cassette. Before loading the cassette tape, the ratio of winding diameter between the supply and take-up reels is computed, and the result is used to set the torque of the reel-driving motors and start the loading operation. At the time of loading, on the other hand, the amount of rotation of the two reels is determined, and the winding diameters of the reels computed from the winding diameter ratio and the amount of drawn-out tape thereby to set a proper tension of the magnetic tape.