Patent ID: 9369718
Filing Date: 2016-06-14
CPC Classification: H04N

Claim Text:
1. A decoding method for decoding a coded picture included in a coded stream, comprising: obtaining, from a header of the coded stream, a plurality of quantization parameter sets each including a quantization scaling matrix and a quantization offset matrix; parsing an identifier for identifying a quantization parameter set from a header of the coded picture included in the coded stream; selecting at least one quantization parameter set from among the plurality of quantization parameter sets, based on the parsed identifier; parsing a first flag from the header of the coded picture, and determining whether the parsed first flag has a predetermined value; parsing a second flag from the header of the coded picture, and determining whether the parsed second flag has the predetermined value; generating a new quantization scaling matrix from another quantization scaling matrix and a first update parameter when the first flag has the predetermined value, the first update parameter being a parameter indicating an amount of change from the another quantization scaling matrix; generating a new quantization offset matrix from another quantization offset matrix and a second update parameter when the second flag has the predetermined value, the second update parameter being a parameter indicating an amount of change from the another quantization offset matrix; and decoding the coded picture by inversely quantizing the coded picture using (i-i) the generated new quantization scaling matrix when the first flag has the predetermined value and (i-ii) a quantization scaling matrix included in the selected quantization parameter set when the first flag does not have the predetermined value, and using (ii-i) the generated new quantization offset matrix when the second flag has the predetermined value and (ii-ii) a quantization offset matrix included in the selected quantization parameter set when the second flag does not have the predetermined value, wherein in said generating the new quantization scaling matrix, the new quantization scaling matrix is generated by (i) obtaining a quantization scaling matrix previously decoded and included in the coded stream, (ii) parsing the first update parameter from the header of the coded picture, and (iii) adding the first update parameter to the quantization scaling matrix previously decoded and included in the coded stream, and in said generating the new quantization offset matrix, the new quantization offset matrix is generated by (i) obtaining a quantization offset matrix previously decoded and included in the coded stream, (ii) parsing the second update parameter from the header of the coded picture, and (iii) adding the second update parameter to the quantization offset matrix previously decoded and included in the coded stream.