VERDICHTUNGSCODIEREINRICHTUNG UND ERWEITERUNGSDECODIEREINRICHTUNG FUER EIN BILDSIGNAL

摘要

A device for coding a picture signal by compression produces, when detected that the amplitude of data which has undergone two-dimensional orthogonal transform and then normalized has overflown, data specifying the normalized data in addition to coded data of the normalized data. A decoding device, therefore, is capable of accurately decoding original picture data despite the overflow. When a block of picture data lies in a predetermined range which occurs with relatively low probability, the picture data is transformed into coded data which includes a predetermined code. When the block of picture data does not lie in such a range, the picture data is converted into Huffman-coded data. This reduces the required capacity of a look-up table for coding.