Encoding circuit for transform coding of a picture signal and decoding circuit for encoding said signal

Encoding circuit for transforming a picture signal into blocks of, for example, 8*8 coefficients, in which each block of coefficients is read motion-adaptively. In the case of motion within a sub-picture, the block of coefficients is read in such an order that the obtained series of coefficients comprises, as it were, two interleaved sub-series. The first series starts with a dc component. In a first embodiment the second series starts with the most relevant motion coefficient. In a second embodiment two interlaced sub-fields are separately transformed and the second series also starts with a dc coefficient. As a result the coefficients are transmitted as much as possible in their order of significance. This particularly produces the largest possible clusters of zero value coefficients.; Such clusters are transmitted as one compact run-length code so that an effective bit rate reduction is achieved, also for moving pictures.