1. An apparatus for decoding video, the apparatus comprising: an extractor configured to obtain a size information of a maximum coding unit and information of whether loop filtering for compensating pixel value is to be performed from the bitstream; a decoder configured to determine the maximum coding unit by splitting a picture, based on the size information of the maximum coding unit, reconstruct encoded image data of the maximum coding unit, and perform the loop filtering on a deblocking filtered data of the reconstructed image data of the maximum coding unit, based on the information of whether loop filtering is to be performed, wherein a coding unit among at least one coding unit in the maximum coding unit includes at least one prediction unit to perform prediction on the coding unit, and wherein the coding unit is split into at least one transformation unit independently from the at least one prediction unit.