A method can include decoding residual signals to generate quantized coefficient components; determining an inverse scan pattern and generating a quantized block using the inverse scan pattern; deriving a quantization parameter and inversely quantizing the quantized block using the quantization parameter to generate a transformed block; and inversely transforming the transformed block to generate a residual block, in which when the quantization parameter is a chroma quantization parameter, the chroma quantization parameter is generated using a luma quantization parameter and an offset parameter indicating a relationship between the luma quantization parameter and the chroma quantization parameter, the luma quantization parameter is derived using a differential quantization parameter and a quantization parameter predictor, and the differential quantization parameter is generated by entropy decoding, and parameters are set according to certain conditions.