VERFAHREN ZUR BILDSIGNALCODIERUNG

摘要

Transformation circuits for carrying out an 8*8 or 2*(4*8) DCT transformation exist. Switching between a 8*8 or 2*(4*8) DCT can be carried out by suitable choice of the logical level of a connecting line. Hybrid coders for picture signals are known which process blocks of progressively scanned input signals using DCT, blocks of 8*8 pixels being coded or decoded in each case. In the case of dynamic picture contents, the lines belonging to a field are combined to form a first 8*8 block, and the lines belonging to the corresponding second field are combined to form a second 8*8 block from these two superposed 8*8 pixel blocks and fed in this form to the hybrid coder. As a result of the reorganization of the input signals, switching between an 8*8 and a 2*(4*8) DCT transformation in the hybrid coder is unnecessary for interlace input signals, but an 8*8 DCT can be advantageously carried out also for a dynamic picture content.