US 11,689,731 B2
Image decoding apparatus and image coding apparatus that involves bi-prediction
Tomonori Hashimoto, Sakai (JP); Tomohiro Ikai, Sakai (JP); Takeshi Chujoh, Sakai (JP); and Eiichi Sasaki, Sakai (JP)
Assigned to SHARP KABUSHIKI KAISHA, Sakai (JP)
Appl. No. 17/276,535
Filed by Sharp Kabushiki Kaisha, Sakai (JP); and FG Innovation Company Limited, New Territories (HK)
PCT Filed Sep. 20, 2019, PCT No. PCT/JP2019/037107
§ 371(c)(1), (2) Date Mar. 16, 2021,
PCT Pub. No. WO2020/059877, PCT Pub. Date Mar. 26, 2020.
Claims priority of application No. 2018-177818 (JP), filed on Sep. 21, 2018.
Prior Publication US 2022/0038720 A1, Feb. 3, 2022
Int. Cl. H04N 19/182 (2014.01); H04N 19/105 (2014.01)
CPC H04N 19/182 (2014.11) [H04N 19/105 (2014.11)] 3 Claims
OG exemplary drawing
 
1. An image decoding apparatus for performing image decoding processing with reference to a prediction image, the image decoding apparatus comprising:
a parameter decoding circuit configured to decode a reference picture indices refldxL0 and refldxL1 for each coding unit (CU) from coded data, and decode a plurality of weight information for each slice header from the coded data; and
a prediction image generation circuit configured to generate a bi-prediction image by using first weight coefficients of a first prediction or second weight coefficients of a second prediction,
wherein the prediction image generation circuit derives variables LumaWeightL0 and LumaWeightL1 based on the weight information, and derives the first weight coefficients of the first prediction equal to LumaWeightL0[refldxL0] and LumaWeightL1[refldxL1],
the prediction image generation circuit derives a Generalized bi-prediction index gbiIndex for each CU, derives a first one of the second weight coefficients of the second prediction equal to gbwTable[gbiIndex], and derives a second one of second weight coefficients based on the first one of the second weight coefficients, the gbiIndex indicates one of elements of the gbwTable, and the gbwTable is a table not decoded from the coded data,
in a case that the first prediction is on, the second prediction is on, and the Generalized bi-prediction index is equal to a predetermined value, the prediction image generation circuit generates the bi-prediction image by using the first weight coefficients of the first prediction, and
in a case that the first prediction is on, the second prediction is on, and the Generalized bi-prediction index is not equal to the predetermined value, the prediction image generation circuit generates the bi-prediction image by using the second weight coefficients of the second prediction.