QUANTIZATION BIT NUMBER EXPANDING METHOD AND QUANTIZATION BIT NUMBER EXPANDING DEVICE

摘要

PPROBLEM 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. PSOLUTION: 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. PCOPYRIGHT: (C)2011,JPO&INPIT