Apparatus for decoding motion information in merge mode

An apparatus for decoding motion information in merge mode, comprising:

• a merge mode motion information decoding unit configured to decode motion information using available spatial and temporal merge candidates when a motion information encoding mode of a current block indicates a merge mode;
• a prediction block generation unit configured to generate a prediction block of the current block using the decoded motion information;
• and
• a residual block decoding unit configured to generate a quantization block by inversely scanning residual signals, inversely quantize the quantization block using a quantization parameter, and generate a residual block by inversely transforming the inverse-quantized block,
• wherein when the current block is not adjacent to a lower boundary of a largest coding unit, a motion vector of a first merge candidate block is determined as a motion vector of the temporal merge candidate if the motion vector of the first merge candidate block is available and a motion vector of a second merge candidate block is determined as the motion vector of the temporal merge candidate if the motion vector of the first merge candidate block is unavailable.