Patent ID: 9699458
Date: 2017-07-04
CPC Classifications: H04N

Claim:
1. An image decoding method that decodes an image by performing prediction processing, comprising: a prediction mode selection step, which selects one of a plurality of prediction modes for the prediction processing; and a prediction step, which performs the prediction processing of the prediction mode selected at the prediction mode selection step, wherein the prediction modes selectable at the prediction mode selection step include: a first intra prediction mode in which first reference pixels are generated employing pixels within a decoded block adjacent to one of left and upper sides of a target block to be decoded, and prediction pixels are generated through computation employing values of decoded second reference pixels adjacent to one of the upper and left sides of the target block to be decoded which is a different side from the first reference pixels and values of the first reference pixels; a second intra prediction mode which is different from the first intra prediction mode and in which prediction pixels are generated employing values of the decoded pixels adjacent to the target block to be decoded; and an inter prediction mode that performs inter prediction processing, and wherein there is a state in the first intra prediction mode in which calculation processing of values of the prediction pixels employing the computation is feasible for any pixels excepting all boundary pixels located at a right end of the target block to be decoded within the target block to be decoded.