Abstract: Audio has become an important digital media transmitted over the network. Retrieval of the audio information from a huge audio database has become an important research topic. From the present situation and the trend in audio information retrieval, we describe and summarize concepts and methods of modern audio information retrieval. Specifically, some key techniques and approaches on contentbased audio information retrieval are discussed.

Key words: audio classification, audio information retrieval
, audio segmentation, auditory perceptual feature