Method and apparatus for encoding video by motion prediction using arbitrary partition, and method and apparatus for decoding video by motion prediction using arbitrary partition

An apparatus for decoding a video, the apparatus comprising:

• a receiver which receives and parses a bitstream of an encoded image;
• a processor which determines coding units having a hierarchical structure being data units in which the encoded image is decoded, and sub-units for predicting the coding units, by using information that indicates division shapes of the coding units and information about prediction units of the coding units, parsed from the received bitstream, wherein the sub-units comprise partitions obtained by splitting at least one of a height and a width of the coding units according to arbitrary ratios;
• and a decoder which reconstructs the image by performing decoding including motion compensation using the partitions for the coding units, using the encoding information parsed from received bitstream,
• wherein the coding units having the hierarchical structure comprise coding units of coded depths split hierarchically according to the coded depths and independently from neighboring coding units.