1. An apparatus for decoding a video, the apparatus comprising : a receiver configured to receive a bitstream; an extractor configured to obtain, from the bitstream, information about a location of a row boundary of a tile; and a decoder configured to determine tiles, including a current tile, based on the information about the location of the row boundary of the tile, and obtain, based on a split information of a coding unit, at least one coding unit from a maximum coding unit included in both the current tile and a current slice segment, wherein all maximum coding units in the current slice segment are included in the current tile, and when the split information indicate a split at a current depth, a coding unit of the current depth is split into coding units of a lower depth.