1. An apparatus configured to decode video by using deblocking filtering, the apparatus comprising: a receiver configured to receive a bitstream including data of a picture, information about a size of a maximum coding unit, and split information; and a decoder configured to split the picture into a plurality of maximum coding units using the information about the size of the maximum coding unit, hierarchically split the maximum coding unit into one or more coding units based on the split information, determine one or more prediction units in one of the coding units using partition type information, wherein the partition type information indicates one of a symmetric type and an asymmetric type, determine one or more transform units in the coding unit using size information of a transform unit, wherein the transform unit is rectangular with a horizontal size and a vertical size indicated by the size information, perform prediction on one of the prediction units in the coding unit and inverse-transformation on one of the transform units in the coding unit, in order to generate a reconstructed coding unit, when a boundary included in the reconstructed coding unit corresponds to at least one of a boundary of the prediction unit and a boundary of the transform unit, determine a boundary strength for the boundary based on at least one of non-zero transformation coefficients, a prediction mode, a motion vector, and a reference index, determine a deblocking filtering method including at least one of a number of filter-taps and a location of pixels to be deblocking-filtered, based on at least one of the boundary strength and neighboring pixels adjacent to the boundary, and perform deblocking filtering on the pixels to be deblocking-filtered according to the deblocking filtering method, in order to generate a filtered coding unit including the deblocking-filtered pixels, wherein: when the split information of a current depth indicates a split, a coding unit of the current depth is split into the coding units of a lower depth, independently from neighboring coding units, and when the split information of the current depth indicates a non-split, at least one prediction unit is obtained from the coding unit of the current depth.