Apparatus of decoding video data

Abstract

An image coding method can include generating a prediction block using an intra prediction mode; generating a prediction block using motion information; transforming residual signals generated using an original block and the prediction block to generate a transformed block; quantizing the transformed block using a quantization parameter to generate a quantized block; determining a scan pattern and applying the scan pattern to the quantized block to generate one-dimensional coefficient information; and entropy-coding the one-dimensional coefficient information, in which the residual signals are transformed in transform unit, a transform type used for transforming the residual signals of luma component is determined by a prediction mode and a size of the transform unit, and a transform type used for transforming the residual signals of chroma components is a DCT-based integer transform, and the quantization parameter is a luma quantization parameter, and a differential quantization parameter is generated by subtracting a quantization parameter predictor from the quantization parameter, and is entropy-coded.