Method and apparatus for encoding video in consideration of scanning order of coding units having hierarchical structure, and method and apparatus for decoding video in consideration of scanning order of coding units having hierarchical structure

An apparatus for decoding a video, the apparatus comprising:

• an obtainer which obtains, from a bitstream, encoded image data of a plurality of maximum coding units, and split information of coding units in a maximum coding unit of the plurality of maximum coding units;
• and
• a decoder which decodes the plurality of maximum coding units according to a raster scanning order, and decodes coding units in the maximum coding unit according to a zigzag scanning order,
• wherein:
• the maximum coding unit is spatially split into the coding units of depths including at least one of a current depth and a lower depth according to the split information,
• when the split information indicates a split for the current depth, the coding unit of a current depth is split into four coding units of a lower depth, independently from neighboring coding units,
• when the split information indicates a non-split for the lower depth, one or more prediction units are obtained from a coding unit of the lower depth,
• the zigzag scanning order on the four coding units of the lower depth is a same order as the raster scanning order on the four coding units.