IMAGE ENCODING METHOD, IMAGE DECODING METHOD, IMAGE ENCODING DEVICE, IMAGE DECODING DEVICE, AND IMAGE ENCODING AND DECODING DEVICE Russian patent published in 2024 - IPC H04N7/00 H04N19/10 

FIELD: image encoding and decoding.

SUBSTANCE: image encoding method includes: performing arithmetic encoding on a first flag (greater1_flag) that indicates whether the absolute value of a target coefficient in the target coefficient block is greater than 1 (S701); and performing arithmetic encoding on a second flag (greater2_flag) that indicates whether the absolute value is greater than 2 (S702). In the first flag arithmetic coding and the second flag arithmetic coding, it is determined whether the immediately preceding coefficient block that was encoded immediately before the target coefficient block includes a coefficient having an absolute value greater than a threshold value (S711). Based on the result of the determination, appropriate contexts are selected for use in arithmetic coding on the first and second flags (S712).

EFFECT: reducing the amount of processing while simultaneously suppressing the deterioration in encoding efficiency.

17 cl, 64 dwg