| 摘要 |
A data transform apparatus transforms four integer data D0-D3 into one DC coefficient Y0 and three AC coefficients Y1-Y3 as lossless-Hadamard transform coefficients. A first calculation unit group adds date D0 to respective data D1 to D3. A first shifter shifts data D0 1 bit to the left. A second calculation unit group subtracts three data calculated by the first calculation unit group from output of the shifter. A second shifter halves a calculation result of the second calculation unit group by shifting the subtraction result 1 bit to the right, and executes round processing for truncating a fractional part of the halved data. A sign inverter inverts the sign of output from the second shifter, and outputs it as DC coefficient. A third calculation unit group subtracts output from the sign inverter from output of the first calculation unit group, and outputs these data as AC coefficients.
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