This web-page accompanies the paper
Klapuri, A., "A method for visualizing the pitch content of polyphonic music signals," in Proc. 10th Int. Society for Music Information Retrieval Conf. (ISMIR 2009), Kobe, Japan, 2009.
In the examples below, the above-cited method was used to calculate the pitch content visualization that was rendered on the staves. Musical key was estimated using  and bar lines using . The input audio signals are taken from the RWC Genre database  and the reference notes (plotted with circles) are from the corresponding MIDI files in the RWC database. It should be noted that the reference MIDI is not 100% accurate either.
 Ryynänen, M. and Klapuri, A., " Automatic Transcription of Melody, Bass Line, and Chords in Polyphonic Music," Computer Music Journal, 32(3), Fall 2008.
 Klapuri, A., Eronen, A., Astola, J., " Analysis of the meter of acoustic musical signals ," IEEE Trans. Audio, Speech, and Language Processing, 14(1), 2006.
 Masataka Goto, Hiroki Hashiguchi, Takuichi Nishimura, and Ryuichi Oka: RWC Music Database: Music Genre Database and Musical Instrument Sound Database, Proceedings of the 4th International Conference on Music Information Retrieval (ISMIR 2003), pp.229-230, October 2003.