Method and apparatus for encoding video by using transformation index, and method and apparatus for decoding video by using transformation index

A method of decoding an encoded video comprising:

• receiving a bitstream of an encoded video;
• determining at least one coding unit by using split information extracted from the bitstream;
• extracting from the bitstream transformation index information indicating whether a transformation unit of a current level included in a coding unit among the at least one coding unit is split;
• when the transformation index information indicates a split of the transformation unit of the current level, splitting the transformation unit of the current level into transformation units of a lower level;
• and
• when the transformation index information indicates a non-split of the transformation unit of the current level, performing an inverse transformation on the transformation unit of the current level to generate residual data corresponding to the transformation unit of the current level,
• wherein the transformation unit of the current level is split into four transformation units of the lower level.