Patent ID: 10623732

Abstract:
An apparatus for encoding an image in intra prediction can include an intra prediction unit generating a prediction block using an intra prediction mode; a transform unit transforming residual signals generated using an original block and the prediction block to generate a transformed block; a quantization unit determining a quantization parameter and quantizing the transformed block using a quantization matrix and the quantization parameter to generate a quantized block; a scanning unit determining a scan pattern and applying the scan pattern to the quantized block to generate one-dimensional coefficient information; and an entropy coding unit entropy-coding the one-dimensional coefficient information and the intra prediction mode, in which the residual signals are transformed in a transform unit, DST-based integer transforms are used for transforming the residual signals if the size of the transform unit is smaller than a predetermined size, and DCT-based transforms are used if the size of the transform unit is equal to or larger than the predetermined size, a differential quantization parameter is generated by subtracting a quantization parameter predictor from the quantization parameter, and is entropy-coded, and if two or more quantization parameters are available among a left quantization parameter, an above quantization parameter and a previous quantization parameter of a current coding unit, the quantization parameter predictor is generated using first two available quantization parameters among the left quantization parameter, the above quantization parameter and the previous quantization parameter, and if only one quantization parameter is available, the available quantization parameter is set as the quantization parameter predictor.