IMAGE CODING METHOD, IMAGE DECODING METHOD, IMAGE CODING DEVICE, IMAGE DECODING DEVICE AND IMAGE CODING AND DECODING DEVICE Russian patent published in 2023 - IPC H03M7/40 H04N19/169 

FIELD: computer technology.

SUBSTANCE: computer technology for decoding images. The technical result consists in reducing the amount of processing while simultaneously suppressing the deterioration in decoding efficiency. The technical result is achieved by selecting a first context to be used in arithmetic decoding of a first target coefficient flag in a target coefficient block, wherein the selection of a context to be used in arithmetic encoding of the first flag is based at least in part on the result of determining whether the immediately preceding block of coefficients is a coefficient having an absolute value greater than the threshold value; arithmetic decoding the first flag using the first context; selecting a second context to be used in arithmetic decoding of a second target coefficient flag in the target coefficient block, wherein selecting a context to be used in arithmetic decoding of the second flag is based at least in part on the result of determining whether the immediately preceding coefficient block includes a coefficient having an absolute value greater than said threshold value, and arithmetic decoding the second flag using the second context; and the threshold value is 1.

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

17 cl, 63 dwg