Method and apparatus for encoding video, and method and apparatus for decoding video

An apparatus for decoding a video, the apparatus comprising:

• an extractor configured to extract, from a bitstream, information about a maximum depth indicating a total number of possible times a maximum coding unit is split, information about a size of a coding unit, and split information indicating whether a coding unit is split into smaller coding units;
• and
• a decoder configured to determine, based on the split information, coding units of a hierarchical structure split from the maximum coding unit and decode the coding units of the hierarchical structure in the maximum coding unit,
• wherein:
• a size of the maximum coding unit is determined using the information about the maximum depth and the information about the size of the coding unit,
• an image is divided into a plurality of maximum coding units based on the size of the maximum coding unit,
• the maximum coding unit, among the plurality of maximum coding units, is hierarchically split into coding units of depths, according to the split information,
• when the split information indicates that a coding unit of a current depth is split, the coding unit of a current depth is split into four coding units of a lower depth, independently from neighboring coding units, and
• when the split information indicates that the coding unit of the current depth is not split, one or more prediction units are obtained from the coding unit of the current depth.