| 摘要 |
PROBLEM TO BE SOLVED: To provide an encoding device which can easily prevent pre-echo and post-echo even in the case of the existence of an attack part or a release part in the head of a block though having a constitution which makes blocks of a digital audio signal to perform spectrum conversion. SOLUTION: A current processing block is divided into sub-blocks e0 to e7, and a sub-block, where the maximum value of a signal A1 is varied from the just preceding sub-block by a prescribed value or more in the current processing block, is discriminated as an attack part, and a gain G1 corresponding to the variation is given to the current processing block and the preceding processing block to perform the gain control. In the case of a signal A2 of which the maximum value does not vary a prescribed value or more in the current processing block, the sub-block e0 is discriminated as an attack part when the maximum value of the sub-block e0 is varied from the maximum value of the preceding processing block by the prescribed value or more and a gain G2 corresponding to the variation is given only for gain correction. Then spectrum conversion is performed by MDCT(modified discrete cosine transform). |
