A method of decoding video data using quantized coefficient components and inter prediction information can include extracting quantized coefficient components and inter prediction information from a received bit stream; applying an inverse scan pattern to the quantized coefficient components to generate a quantized block having a size of a transform unit; generating a quantization parameter per quantization unit which is a unit for deriving a quantization parameter and inverse-quantizing the quantized block to generate a transformed block; generating a residual block by inverse-transforming the transformed block; deriving motion information and generating a prediction block; and generating a reconstructed block by using the residual block and the prediction block.