Audio decoder and audio decoding method

摘要

First determiner 121 provisionally determines whether a current processing unit is a stationary noise region based on a determination result on stationary characteristics of a decoded signal. Based on the provisional determination result and a determination result on periodicity of the decoded signal, second determiner 124 further determines whether the current processing unit is a stationary noise region, whereby a decoded signal including a stationary speech signal such as a stationary vowel is distinguished from a stationary noise, and thus the stationary noise region is detected accurately.