Patent ID: 7440503

Claim:
A decoding apparatus for decoding, on a block basis, input coded data of a plurality of blocks which are provided by dividing an image signal into blocks, by performing a compression coding on the blocks in a predetermined order, and by adding sync information to the coded data on an m blocks basis, m being a natural number, comprising: storing means for storing the coded data on the m blocks basis; detecting means for detecting erroneous data included in the input coded data, on the m blocks basis, wherein said storing means stores a detecting result with respect to the sync information; decoding means having a first decoding mode for decoding the coded data in the predetermined order and a second decoding mode for decoding the coded data in an order opposite to the predetermined order, on the block basis, and selecting the first decoding mode and the second decoding mode in accordance with the detecting result of said detecting means so that the second decoding mode is selected on the m blocks basis when said detecting means detects the erroneous data and the first decoding mode is selected on the m blocks basis when said detecting means does not detect the erroneous data; and output means for outputting the data decoded by said decoding means, in the predetermined order regardless of the result of the detection by said detecting means and the decoding mode selected by said decoding means, wherein said storing means stores a flag for the detecting result, and wherein said decoding means decodes the coded data in the m blocks basis in the predetermined order from a first sync block to the sync block just before the sync block having errors, and in the order opposite to the predetermined order from the last sync block to the sync block just before the sync block having errors.