US 12,081,799 B2
Encoding device, decoding device and program
Shunsuke Iwamura, Tokyo (JP); Shimpei Nemoto, Tokyo (JP); and Atsuro Ichigaya, Tokyo (JP)
Assigned to NIPPON HOSO KYOKAI, Tokyo (JP)
Filed by NIPPON HOSO KYOKAI, Tokyo (JP)
Filed on Jun. 24, 2022, as Appl. No. 17/849,233.
Application 17/849,233 is a continuation of application No. PCT/JP2020/048304, filed on Dec. 23, 2020.
Claims priority of application No. 2019-235621 (JP), filed on Dec. 26, 2019.
Prior Publication US 2022/0329863 A1, Oct. 13, 2022
Int. Cl. H04N 19/61 (2014.01)
CPC H04N 19/61 (2014.11) 10 Claims
OG exemplary drawing
 
1. An encoding device that performs an encoding process in units of blocks into which images constituted by luminance signals and chrominance signals are divided, the encoding device comprising:
a predictor configured to predict a target chrominance block which is an encoding target block of the chrominance signals and generate a prediction chrominance block;
a residual generator configured to generate a chrominance prediction residual indicating a difference between the target chrominance block and the prediction chrominance block; and
a transformer configured to apply a transform process to the chrominance prediction residual and generate transform coefficients, wherein
the transformer includes:
a transform candidate specifier configured to specify, according to a signal format, transform type candidates applicable to the transform process; and
a transform type determiner configured to:
determine a transform type applied to the transform process of a reference luminance block, that is a luminance block corresponding to a position of the target chrominance block, as the transform type to be applied to the transform process when the transform type candidates include the transform type applied to the transform process of the reference luminance block; and
determine a predetermined transform type as the transform type to be applied to the transform process when the transform type candidates do not include the transform type applied to the transform process of the reference luminance block.