An apparatus for decoding video data, the apparatus comprising: a receiver which receives and parses a bitstream comprising encoded video data; an extractor which extracts, from the bitstream, the encoded video data, information about a maximum size of a coding unit, split information of a coding unit, and information on a relationship between a depth of a coding unit and a quantization mode, wherein the quantization mode indicates whether a quantization parameter delta is to be used; and a decoder which decodes the encoded video data by performing inverse-quantization, wherein: an image is split into a plurality of maximum coding units using the information about a maximum size of a coding unit, the maximum coding unit is hierarchically split into one or more coding units of depths including at least one of a current depth and a lower depth according to the split information of the coding unit, further comprising, for a coding unit of the current depth: the extractor further determines whether the quantization parameter delta is to be used in the coding unit of the current depth, based on the information on said relationship, when the split information indicates a split for the current depth, the coding unit of the current depth is split into four coding units of the lower depth, independently from neighboring coding units, and when the split information indicates a non-split for the current depth, transformation units are determined from the coding unit of the current depth, and the decoder performs inverse-quantization on the transformation units using the result of the determination of whether the quantization parameter delta is to be used in the coding unit of the current depth. a receiver which receives and parses a bitstream comprising encoded video data; an extractor which extracts, from the bitstream, the encoded video data, information about a maximum size of a coding unit, split information of a coding unit, and information on a relationship between a depth of a coding unit and a quantization mode, wherein the quantization mode indicates whether a quantization parameter delta is to be used; and a decoder which decodes the encoded video data by performing inverse-quantization, an image is split into a plurality of maximum coding units using the information about a maximum size of a coding unit, the maximum coding unit is hierarchically split into one or more coding units of depths including at least one of a current depth and a lower depth according to the split information of the coding unit, further comprising, for a coding unit of the current depth: the extractor further determines whether the quantization parameter delta is to be used in the coding unit of the current depth, based on the information on said relationship, when the split information indicates a split for the current depth, the coding unit of the current depth is split into four coding units of the lower depth, independently from neighboring coding units, and when the split information indicates a non-split for the current depth, transformation units are determined from the coding unit of the current depth, and the decoder performs inverse-quantization on the transformation units using the result of the determination of whether the quantization parameter delta is to be used in the coding unit of the current depth. the extractor further determines whether the quantization parameter delta is to be used in the coding unit of the current depth, based on the information on said relationship, when the split information indicates a split for the current depth, the coding unit of the current depth is split into four coding units of the lower depth, independently from neighboring coding units, and when the split information indicates a non-split for the current depth, transformation units are determined from the coding unit of the current depth, and the decoder performs inverse-quantization on the transformation units using the result of the determination of whether the quantization parameter delta is to be used in the coding unit of the current depth.