Image encoding method and image encoding apparatus

An image encoding method, comprising:

• dividing a current picture to be encoded into a plurality of processing blocks;
• and
• selecting, for each of the plurality of processing blocks, one of intra prediction modes specified by a predetermined coding standard, and performing intra prediction according to the selected intra prediction mode,
• wherein the intra prediction modes include a lower-left reference mode in which a processing block located at lower left of a current processing block to be processed is referred to and a non lower-left reference mode in which a processing block located at lower left of a current processing block to be processed is not referred to,
• the plurality of processing blocks include a first processing block and a second processing block located at upper right of the first processing block,
• the predetermined coding standard defines that information on the second processing block is written into a bitstream after information on the first processing block, and
• in the selecting and performing intra prediction, (i) intra prediction is performed on the second processing block according to the non lower-left reference mode, and subsequently, (ii) intra prediction is performed on the first processing block according to the intra prediction mode selected from among the intra prediction modes.

An image encoding apparatus, comprising:

• a dividing unit configured to divide a current picture to be encoded into a plurality of processing blocks;
• and
• an intra prediction unit configured to select, for each of the plurality of processing blocks, one of intra prediction modes specified by a predetermined coding standard, and perform intra prediction according to the selected intra prediction mode,
• wherein the intra prediction modes include a lower-left reference mode in which a processing block located at lower left of a current processing block to be processed is referred to and a non lower-left reference mode in which a processing block located at lower left of a current processing block to be processed is not referred to,
• the plurality of processing blocks include a first processing block and a second processing block located at upper right of the first processing block,
• the predetermined coding standard defines that information on the second processing block is written into a bitstream after information on the first processing block, and
• the intra prediction unit is configured to (i) perform intra prediction on the second processing block according to the non lower-left reference mode, and subsequently, (ii) perform intra prediction on the first processing block according to the intra prediction mode selected from among the intra prediction modes.