Patent ID: 9723316
Date: 2017-08-01
CPC Classifications: H04N

Claim:
1. An image decoding device comprising: an intra prediction unit for, when a coding mode for a coding block is an intra coding mode, carrying out an intra-frame prediction process on each of processing blocks to generate a prediction image, each of the processing blocks being the coding block or a sub-block obtained by dividing the coding block, wherein, when an intra prediction parameter indicates a horizontal prediction process and a size of the processing block is less than a predetermined size, said intra prediction unit adds a value to a signal value of a pixel adjacent to left of said processing block and outputs a result of the addition as a predicted value of said prediction image, the value being proportional to an amount of change in a horizontal direction of signal values of pixels adjacent to top of said processing block, and when the intra prediction parameter indicates the horizontal prediction process and the size of the processing block is greater than or equal to the predetermined size, said intra prediction unit outputs the signal value of the pixel adjacent to left of the processing block as the predicted value of the prediction image.