| 摘要 |
PROBLEM TO BE SOLVED: To encode data without duplicating information so as to improve coding efficiency, and decode the coded data. SOLUTION: A coding unit 15-1 of a CPU 15 performs entropy coding of the quantized data in the descending order of importance of each frequency band, and deletes all MDCT coefficient of frequency band when a total code amount of the coded data exceeds a target code amount. The coding unit 15-1 sets a presence flag to 1 in order so as not to encode the MDCT coefficient of the frequency band. The envelope value of the frequency band becomes 0 so that the coding unit 15-1 prevents duplication of information by encoding only the recalculated envelope value without coding the presence flag. A decoding unit 15-2 decodes the encoded data by setting 0 in the MDCT coefficient of the frequency band whose envelope value has become 0. COPYRIGHT: (C)2009,JPO&INPIT
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