Encoding method, encoding apparatus, and program

A coding apparatus, comprising:

• a partitioner configured to partition a first block having a predetermined size in an original image into a group of second blocks each being a block serving as a unit for coding, by quad tree, ternary tree, or binary tree;
• and
• a predictor configured to predict movement for each of the second blocks,
• wherein the partitioner includes a first sub-partitioner and a second sub-partitioner,
• the first sub-partitioner partitions a whole of the first block by any one of the quad tree, the ternary tree, or the binary tree,
• the second sub-partitioner further partitions, by any one of the quad tree, the ternary tree, or the binary tree not selected in the first sub-partitioner, parts of the first block partitioned, to generate the second blocks, and
• the predicting includes executing accurate prediction processing for each of the second blocks by progressively increasing the kinds of multiple reference lines to three as a final stage of the partitioning is approaching,
• wherein each of the partitioner, the first sub-partitioner and the second sub-partitioner is implemented by:
• i) computer executable instructions executed by at least one processor,
• ii) at least one circuit or
• iii) a combination of computer executable instructions executed by at least one processor and at least one circuit.