| 摘要 |
PROBLEM TO BE SOLVED: To provide a quantization bit number expanding method capable of significantly improving sound quality, by expanding the quantization bit number of a digital audio signal, with simple processing. SOLUTION: A quantization bit number expanding device includes: a flat section detection unit for detecting a flat section from an audio signal; a pattern determination unit for determining a shape pattern of the flat section depending on whether a preceding difference value just before the flat section, and a following difference value just after the flat section are positive or negative; a waveform estimation unit for estimating a detailed waveform of the flat section, based on the shape pattern and a ratio of the preceding difference value/the following difference value; and a sample value determination unit for determining a sample value of each sample time of the flat section with the large quantization bit number based on the detailed waveform. COPYRIGHT: (C)2011,JPO&INPIT
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