| 摘要 |
There is provided a quantization bit rate expansion method and a quantization bit rate expansion device that make it possible to noticeably enhance sound quality by expanding the quantization bit rate of a digital audio signal through simple processing. The quantization bit rate expansion device includes a flat period detection unit that detects a flat period from the audio signal, a pattern determination unit that determines a profile pattern of the flat period according to a positive or negative sign of a preceding difference value immediately preceding the flat period and a positive or negative sign of a subsequent difference value immediately subsequent to the flat period, a waveform estimation unit that estimates a detailed waveform according to the profile pattern a ratio of the preceding difference value to the subsequent difference value, and a sample value determination unit that determines, based on the detailed waveform, sample values for respective sampling times of the flat period by means of a quantization bit rate that is larger than the quantization bit rate of the audio signal. |
