Video coding apparatus

A video coding apparatus comprising:

• a block dividing section that divides each of frames of a video signal into a plurality of blocks;
• an intraprediction section that generates prediction signals by a plurality of intra prediction modes for each of the blocks divided by the block dividing section;
• an interprediction section that generates prediction signals by a plurality of interprediction modes for each of the blocks divided by the block dividing section;
• and
• a prediction mode determination section that selects an optimum prediction mode from among the plurality of intraprediction modes and the plurality of interprediction modes, the prediction mode determination section comprising:
• an interprediction mode determination section that selects a first prediction mode candidate from among the plurality of the interprediction modes;
• a candidate limiting section that that determines a picture type of a picture to which a macroblock subjected to a coding belongs and selects, when the determined picture type is a P-picture, a group of candidates from among the plurality of the intraprediction modes to be either one of (1) intraprediction modes using a DCT block size that is the same with a DCT block size used in the first prediction mode candidate or (2) intraprediction modes using a block size that is the same or smaller than a block size used in the first prection mode candidate;
• an intraprediction mode determination section that selects a second prediction mode candidate from among the group of candidates selected by the candidate limiting section;
• and
• an intra-inter-prediction mode determination section that selects one of the first prediction mode candidate and the second prediction mode candidate as the optimum prediction mode.