Orthogonal transform method, orthogonal transform apparatus, encoding method, encoding apparatus, inverse orthogonal transform method, inverse orthogonal transform apparatus, decoding method, and decoding apparatus.

摘要

In a four-by-four orthogonal transform mode, an input data buffer(33) enters a first half of entered eight pieces of pixel data, i.e., "x0A", "x1A", "x2A", and "x3A", into each of the first to fourth multiply-and-accumulation (MAC) operation circuit(34a)-(34d)s, while feeding a second half of the entered eight pieces of pixel data, i.e., "x0B", "x1B", "x2B", and "x3B", into each of the fifth to eighth MAC operation circuit(34e)-(34h)s. In an eight-by-eight orthogonal transform mode, the input data buffer(33) feeds entered eight pieces of pixel data into each of the first to eighth MAC operation circuit(34a)-(34h)s. Since the input data buffer(33) receives the eight pieces of pixel data in each of the four-by-four and eight-by-eight orthogonal transform modes, an orthogonal transform circuit(100) is activated once in each of the four-by-four and eight-by-eight orthogonal transform modes. In both of the four-by-four and eight-by-eight orthogonal transform modes, the same first to eighth MAC operation circuit(34a)-(34h)s are used to produce the orthogonal transform coefficient data. This feature inhibits an increase in hardware area. <IMAGE>