REVERSE QUANTIZATION DEVICE, AUDIO DECODER, IMAGE DECODER, REVERSE QUANTIZATION METHOD AND REVERSE QUANTIZATION PROGRAM

摘要

PROBLEM TO BE SOLVED: To provide a reverse quantization device with small circuit scale and small operation error.

SOLUTION: Reverse quantization processing for inputting a scale factor index Scf, bit allocation Ba and a quantization code X and outputting a reverse quantization value Y is performed by reducing frequency of multiplication by using bit shift processing. Even when the multiplication is performed only once, an error to be generated in a single multiplication is suppressed to be small not only by taking out a part of integer power of 2 as first shift quantity S1 from the scale factor index but taking out a part of the integer power of 2 as second shift quantity S2 from the bit allocation Ba and a reference value R and replacing multiplication processing to the quantization code X with the bit shift processing as much as possible.

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