I. Introduction
When listening to music, people spontaneously tap their fingers or feet according to the music's periodic structure. Dancing with music is a human nature to express meaning of music or to show people's emotion. In recent years, hip-hop culture drives the development of street dance, and learning to dance has deeply attracted young people. Due to popularity of street dance and ease of video capturing, many dancers record their dances and share them on the web. However, quality of these videos, especially the audio tracks accompanying with the videos, is generally low. Moreover, to promote dance competitions or TV shows, music videos are elaborately produced by experts who have ample knowledge on choreography, music rhythm, and video editing. It is never an easy task for amateur dancers who want to share or preserve their performances for entertainment or education purposes.