Device for transmitting or storing digital television pictures in which a maximum possible number of data of a group of transformed pixel blocks (DB1 ... DB12) is transmitted in the form of variable-length code words (V1 ... VN) in a corresponding channel block of predetermined length (Fig. 5A). If all code words of the groups of blocks are accommodated in the corresponding channel block (Fig. 5C), the channel block will also comprise surplus data of other blocks. The boundary, within a channel block, between these code words and surplus data is transmitted in the form of an address (P) which is accommodated at a predetermined position of the channel block.; If the channel block length is inadequate for transmitting all code words of the gr...