Patent ID: 9712824
Date: 2017-07-18
CPC Classifications: H04N

Claim:
1. A method of inversely quantizing a quantized block, the method comprising: restoring a differential quantization parameter; generating a quantization parameter predictor; generating a quantization parameter using the differential quantization parameter and the quantization parameter predictor; and inversely quantizing the quantized block using the quantization parameter and a quantization matrix, wherein the differential quantization parameter is restored using a bin string indicating an absolute value of the differential quantization parameter and a bin indicating a sign of the differential quantization parameter, 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 two available quantization parameters determined according to a predetermined order, the quantization parameter is restored per quantization unit, and a minimum size of the quantization unit is adjusted by a picture parameter set, if the quantization matrix is a user-defined quantization matrix, the quantization matrix is restored by using an inverse DPCM (differential pulse code modulation), and the quantized block is generated by inversely scanning significant flags, coefficient signs and coefficient levels according to an inverse scan pattern which is selected based on an intra prediction mode and a size of a transform unit.