US 11,683,494 B2
Moving image coding device and method using chrominance format and intra-frame prediction mode
Yukinobu Yasugi, Sakai (JP); and Tomohiro Ikai, Sakai (JP)
Assigned to SHARP KABUSHIKI KAISHA, Sakai (JP); and FG Innovation Company Limited, Tuen Mun (HK)
Appl. No. 17/299,980
Filed by SHARP KABUSHIKI KAISHA, Sakai (JP); and FG Innovation Company Limited, Tuen Mun (HK)
PCT Filed Dec. 3, 2019, PCT No. PCT/JP2019/047252
§ 371(c)(1), (2) Date Jun. 4, 2021,
PCT Pub. No. WO2020/116455, PCT Pub. Date Jun. 11, 2020.
Claims priority of application No. JP2018-230200 (JP), filed on Dec. 7, 2018.
Prior Publication US 2021/0377538 A1, Dec. 2, 2021
Int. Cl. H04N 19/132 (2014.01); H04N 19/159 (2014.01); H04N 19/186 (2014.01); H04N 19/46 (2014.01)
CPC H04N 19/132 (2014.11) [H04N 19/159 (2014.11); H04N 19/186 (2014.11); H04N 19/46 (2014.11)] 9 Claims
OG exemplary drawing
 
1. A moving image decoding device for generating a prediction image by using an intra-frame prediction mode, the moving image decoding device comprising:
at least one processor; and
at least one storage device coupled to the at least one processor and storing computer- executable instructions which, when executed by the at least one processor, cause the moving image decoding device to:
derive a first parameter and a second parameter by using a sampled luminance value downsampled according to a chrominance format and the intra-frame prediction mode; and
derive the prediction image by using the first parameter and the second parameter, wherein:
the first parameter is derived by
deriving a logarithmic value of a luminance difference value,
deriving a first value by right-shifting a second value related to the luminance difference value by the logarithmic value, and
using a third value acquired by multiplying a fourth value by a chrominance difference value, wherein the fourth value is determined from a reference table by using the first value, and
the second parameter is derived by using the first parameter.