Audio Thumbnailing Using MPEG-7 Low Level Audio Descriptors

In this paper we present an audio thumbnailing technique based on audio segmentation by similarity search. The segmentation is performed on MPEG-7 low level audio feature descriptors as a growing source of multimedia meta data. Especially for database applications or audio-on-demand services this technique could be very helpful, because there is no need to have access to the probably copyright protected original audio material. The result of the similarity search is a matrix which contains off-diagonal stripes representing similar regions, which are usually the refrains of a song and thus a very suitable segment to be used as audio thumbnail. Using the a priori knowledge that we search off-diagonal stripes which must represent several seconds of audio data and that the adjustment of the stripes must be characteristically, we implemented a filter to enhance the structure of the similarity matrix and to extract a relevant segment as a audio thumbnail.