1. A video decoding apparatus comprising: an extractor which extracts from a bitstream first pattern information indicating whether residual samples of a current coding unit are equal to 0, and when the first pattern information indicates the residual samples are not equal to 0, extracts from the bitstream transformation index information indicating whether a transformation unit of a current level included in the current coding unit is split; a decoder which splits the transformation unit of the current level into transformation units of a lower level when the transformation index information indicates a split of the transformation unit of the current level, wherein the extractor further extracts second pattern information for the transformation unit of the current level when the transformation index information indicates a non-split of the transformation unit of the current level, wherein the second pattern information indicates whether the transformation unit of the current level contains one or more transform coefficients not equal to 0.