A method of reconstructing video data using a merge mode, wherein, in merge mode, motion information of one of merge candidate blocks is set as motion information of a current prediction unit, the method comprising: constructing a merge candidate list using available spatial and temporal merge candidate blocks; setting motion information of a merge candidate block on the merge candidate list corresponding to a merge index as motion information of a current prediction unit; generating a predicted block of the current prediction unit using the motion information, wherein if a motion vector in the motion information indicates a pixel position, the predicted block is generated by copying a block of a reference picture specified by the motion vector and if the motion vector indicates a sub-pixel position, the predicted block is generated by interpolating pixels of the reference picture; generating a transformed block by inverse-quantizing a block of quantized coefficients using a quantization parameter; generating a residual block by inverse-transforming the transformed block; and generating a reconstructed block using the predicted block and the residual block, wherein when the current prediction unit is a second prediction unit partitioned from a current coding unit by asymmetric partitioning, the spatial merge candidate block corresponding to a first prediction unit partitioned from the current coding unit by the asymmetric partitioning is set as unavailable, and wherein a temporal merge candidate block is determined depending on a position of the current prediction unit within a largest coding unit, LCU, wherein a first temporal merge candidate block is a right-below corner block of a block (i) having the same size and (ii) same location of the current prediction unit and (ii) being located within a temporal merge candidate picture, and wherein if the first temporal candidate block belongs to a lower LCU, the first temporal candidate block is set as unavailable, wherein the quantization parameter is derived per quantization unit by using a differential quantization parameter and a quantization parameter predictor, wherein a minimum size of the quantization unit is adjusted per picture, and wherein a reference picture index of the temporal merge candidate is set as 0. constructing a merge candidate list using available spatial and temporal merge candidate blocks; setting motion information of a merge candidate block on the merge candidate list corresponding to a merge index as motion information of a current prediction unit; generating a predicted block of the current prediction unit using the motion information, wherein if a motion vector in the motion information indicates a pixel position, the predicted block is generated by copying a block of a reference picture specified by the motion vector and if the motion vector indicates a sub-pixel position, the predicted block is generated by interpolating pixels of the reference picture; generating a transformed block by inverse-quantizing a block of quantized coefficients using a quantization parameter; generating a residual block by inverse-transforming the transformed block; and generating a reconstructed block using the predicted block and the residual block, wherein when the current prediction unit is a second prediction unit partitioned from a current coding unit by asymmetric partitioning, the spatial merge candidate block corresponding to a first prediction unit partitioned from the current coding unit by the asymmetric partitioning is set as unavailable, and wherein a temporal merge candidate block is determined depending on a position of the current prediction unit within a largest coding unit, LCU, wherein a first temporal merge candidate block is a right-below corner block of a block (i) having the same size and (ii) same location of the current prediction unit and (ii) being located within a temporal merge candidate picture, and wherein if the first temporal candidate block belongs to a lower LCU, the first temporal candidate block is set as unavailable, wherein the quantization parameter is derived per quantization unit by using a differential quantization parameter and a quantization parameter predictor, wherein a minimum size of the quantization unit is adjusted per picture, and wherein a reference picture index of the temporal merge candidate is set as 0.