| 摘要 |
PROBLEM TO BE SOLVED: To efficiently create a bit stream with good sound quality by properly suppressing pre-echo while holding coding efficiency. SOLUTION: An audio signal coding device includes an attack detector (2) for detecting rapid amplitude change in an audio input signal as attack detection information; a filter bank (6) for converting the audio input signal of a time region in a processing object frame into a frequency spectrum in accordance with conversion block length; a group determination part (7) for grouping a frequency spectrum, on the basis of the attack detection information into groups of a smaller number than a block number when frequency conversion is performed in block length in which the filter bank part is short; and a quantization part (9) for quantizing the frequency spectrum grouped in accordance with determined bit ration. COPYRIGHT: (C)2006,JPO&NCIPI
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