US 12,289,468 B2
Prediction image generation apparatus, video decoding apparatus, video coding apparatus, and prediction image generation method
Yukinobu Yasugi, Sakai (JP); Eiichi Sasaki, Sakai (JP); Tomohiro Ikai, Sakai (JP); and Tomoko Aono, Sakai (JP)
Assigned to SHARP KABUSHIKI KAISHA, Sakai (JP)
Filed by Sharp Kabushiki Kaisha, Osaka (JP)
Filed on Feb. 9, 2024, as Appl. No. 18/437,897.
Application 18/437,897 is a continuation of application No. 18/207,730, filed on Jun. 9, 2023, granted, now 11,979,604.
Application 18/207,730 is a continuation of application No. 17/867,736, filed on Jul. 19, 2022, granted, now 11,722,696, issued on Aug. 8, 2023.
Application 17/867,736 is a continuation of application No. 17/413,677, granted, now 11,451,825, issued on Sep. 20, 2022, previously published as PCT/JP2019/049451, filed on Dec. 17, 2019.
Claims priority of application No. 2018-238526 (JP), filed on Dec. 20, 2018.
Prior Publication US 2024/0187646 A1, Jun. 6, 2024
Int. Cl. H04N 19/593 (2014.01); H04N 19/105 (2014.01); H04N 19/186 (2014.01); H04N 19/80 (2014.01)
CPC H04N 19/593 (2014.11) [H04N 19/105 (2014.11); H04N 19/186 (2014.11); H04N 19/80 (2014.11)] 3 Claims
OG exemplary drawing
 
1. A prediction image generation apparatus for generating a prediction image based on an intra prediction parameter including a Cross-Component Linear Model (CCLM) prediction mode, the prediction image generation apparatus comprising:
a CCLM prediction parameter derivation circuitry that derives (i) a first Cross-Component Linear Model (CCLM) prediction parameter and (ii) a second Cross-Component Linear Model (CCLM) prediction parameter; and
a CCLM prediction filter circuitry that derives the prediction image by adding a value of the second CCLM prediction parameter to a value obtained by right-shifting a product of a luminance value and a value of the first CCLM prediction parameter by a first shift value,
wherein
the first CCLM prediction parameter is derived by right shifting a first variable by a second shift value,
the first variable is a sum of (i) a second variable and (ii) a value of a rounding parameter,
the rounding parameter is a value obtained by right shifting a value based on a chrominance difference value to one bit,
the second variable is a product of (i) the chrominance difference value and (ii) a result of a bit-wise “or” of (a) a value in a reference table defined by using an index and (b) an offset value equal to 8,
the second shift value is a value obtained by converting a logarithmic value of the chrominance difference value into an integer, and is derived without being based on a luminance value,
the first shift value is a value obtained by adjusting an initial value by (i) the second shift value and (ii) a value obtained by adjusting a logarithmic value of a luminance difference value by the index, and
the index is an index for referring to the reference table, and is a value obtained by shifting the luminance difference value by the logarithmic value.