Music content analysis in MP3 compressed domain

Nowadays more and more audio contents are stored in compressed formats. Especially MP3 music has become very popular with the availability of powerful computation and wide bandwidth connectivity. So that, this chapter will be devoted to present techniques and algorithms, dealing with compressed audio, aimed at content analysis. Since content analysis in compressed domain is an innovative field of applications, the literature review will be extended to methods that extract music content from MP3, even if the algorithms are not focused on music information retrieval. In this chapter we focus on a number of different algorithms dealing with common tasks of the MIR field such as tempo induction, tempo tracking, and automatic music synchronization. We will present an overview of the MusicXML, and IEEE1599 language to represent score and synchronization results, because we have decided to use those formats to represent the score in our synchronization algorithm. The chapter will end showing applications, conclusions, and future works in the field of direct content analysis in compressed domain.