Abstract: A method for recording images in a digital video cassette recorder, which utilizes high compressibility, and which is advantageous in an interframe coding method, includes steps for regularly and repeatedly recording low-frequency data of an intraframe corresponding to the outline of a picture in a group of pictures (GOP) unit and providing remaining data recording area in an end area of each GOP unit to permit data quantity fixation and in order to perform trick play operations. Furthermore, the method orders sub-images of a picture regularly or irregularly while recording the low-frequency data of all the sub-images which belong to a same cluster in low-frequency data recording area of each sub-image, to thereby raise picture quality during trick play.

Abstract: A method for digital magnetic recording and reproducing of video images while compressively encoding video image data to reduce a bit rate includes the steps of forming the compressed data into sync-block units corresponding to minimum units for error-correcting, recording the compressed data as sync block units on a plurality of tracks of a digital magnetic tape, and reproducing a recognizable image corresponding to the video image data from the recorded compressed data. According to one aspect of the method, the sync blocks are arranged so as to be recorded on the plurality of tracks using a line sequential scanning method in the track-traversing direction, and the arranged sync blocks are restored to their original locations during reproduction. A digital magnetic recording and reproducing apparatus suitable for implementing the above method is also disclosed.

Abstract: An image compression system using the setting of fixed bit rates for compressing an image wherein image blocks are sorted into classes in accordance with the activities of the blocks, the activities being obtained by dividing an original image by a predetermined unit. Individual scale factors are given for each block, so that coding is carried out by fixing the allocating amount of bits to blocks to be coded.

Abstract: Disclosed is a digital image compression and decompression method and apparatus for dividing a supplied digital image signal into blocks of predetermined size, performing variable-length coding of the signal, separating the signal with respect to principle information and remaining information, and controlling the record format so that each type of information is alternately recorded on a recording medium in an equal interval whenever recording the compressed information and decompressing the information, according to the reverse order, during decoding. Also, the function for extracting an activity in two steps during coding and then controlling the permitted number of bits of the variable length coding is provided. Accordingly, the coding efficiency is improved and the circuitry is simplified so that the price of the end product can be lowered.