Video encoding apparatus and method, and video decoding apparatus and method

The image encoding apparatus and method, and image decoding apparatus and method are disclosed. The image encoding apparatus according to an embodiment of the present invention, to separate, the current block with respect to an input image into a plurality of sub-blocks according to the position of the pixel block to the separating section; Key block encoder to choose between any of the key block having a plurality of sub-blocks of size greater than at least one pixel size of the separation by the current block separation unit, and executing the intra prediction or the inter prediction for the selected key block; And the rest other than the key block selected ones of the separated sub-block the non-specified in the key block, the key block and the non-specified using the peripheral pixel values ​​of the current block is restored based on the unit key block coded-for key block intra non-executing prediction - characterized in that it comprises a key block coding portion. According to the invention, even if the increase in the size of the basic block of code for the encoding of high-resolution video it becomes possible to efficiently remove the spatial redundancy within a block.