Intra-prediction mode determination method, intra-prediction mode determination device, and storage medium for storing intra-prediction mode determination program

Abstract

An intra-prediction mode determination device is applied in a video coding device that recursively divides input video blocks into small blocks to perform coding by intra-prediction or inter-frame prediction, and includes a prediction mode selection unit and a number of bins adjustment unit that are provided in correspondence to only one of possible sizes of the small blocks. The prediction mode selection unit evaluates, with respect to each of the small blocks, the coding cost of a plurality of prediction mode candidates on the basis of a residual corresponding to the prediction mode candidates and the number of bins allocated to the prediction mode candidates, and selects an intra-prediction mode from the plurality of prediction mode candidates. The number of bins adjustment unit, when the prediction mode selection unit evaluates the coding cost, increases the number of bins corresponding to a specific prediction mode candidate.