Patent ID: 8923634

Claim:
A decoding method for decoding last position information indicating a horizontal position and a vertical position of a last non-zero coefficient in a predetermined order within a current block to be decoded, the current block being included in a picture and including a plurality of coefficients, the decoding method comprising: obtaining a bitstream including a first partial signal, a second partial signal, a third partial signal, and a fourth partial signal, in this order; performing first arithmetic decoding on the first partial signal and the third partial signal respectively to obtain a decoded first partial signal and a decoded third partial signal, the first arithmetic decoding being context adaptive arithmetic decoding using a variable probability that is updated based on decoded last position information of a decoded block different from the current block; performing second arithmetic decoding on the second partial signal and the fourth partial signal respectively to obtain a decoded second partial signal and a decoded fourth partial signal, the second arithmetic decoding being bypass decoding using a fixed probability; deriving a horizontal component of the last position information indicating the horizontal position of the non-zero coefficient from the decoded first partial signal and the decoded third partial signal; and deriving a vertical component of the last position information indicating the vertical position of the non-zero coefficient from the decoded second partial signal and the decoded fourth partial signal.