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Following a Pianist's Paces Exploring the Information Revealed by Tempo Changes A class project for ISE575b, Spring 2006 |
This project develops a program that allows users to visualize the relations between tempo changes, loudness, and musical scores of real performances in audio recordings. Tempo change is the most obvious and recognizable feature that can be observed in expressive performances. Many of previous studies indicate that performers use tempo changes for various musical ideas and information. For instances, the boundary of phrases is usually emphasized by acceleration in the beginning and deceleration at the end. However, extracting correct tempo changes is a difficult task, which limits the number of pieces tested in previous researches. To solve this problem, one of the key characteristics of this project is that users can manually input tempo changes, so that any audio recordings can be analyzed. The program also provides the loudness information of audio and the score information from a MIDI file. Users can easily observe the relations between tempo changes, loudness, and score (phrase structure) through the program graphic interface. It can also be used as a tool for MIDI and audio alignment.
This program is a stand-alone, platform independent software developed in Java. The interface contains four parts: control panel, MIDI panel, audio panel, and tempo panel.
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Control Panel The control panel (the most upper part) controls opening a MIDI/audio file, playing the audio recording, and recording the tempo changes inputted by users. It also shows the information of playing time and current tempo. MIDI Panel When a MIDI file is opened, the MIDI panel draws the first four bars of notes in score. The representation is not a formal score because detecting note duration and pitch spelling are beyond the scope of this project. However, the ˇ§dot-likeˇ¨ visualization allow users to easily detect phrase boundaries by looking for the repeated or different patterns. Audio Panel The audio panel contains two parts. The upper part shows the amplitude of audio wave. The lower part is a progress bar, identifying how long the audio has been played and which part of the wave is played at the moment. Tempo Panel The tempo panel tracks the tempo changes entered by users. The information is aligned with audio wave, which makes it easier to reveal the relation between tempo changes and loudness dynamics. |
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Open Files
Click the ˇ§Open a MIDIˇKˇ¨ button to open a MIDI file. Click the ˇ§Open an AudioˇKˇ¨ button to load a corresponding audio recording.
Play/Reset Buttons
Click the ˇ§Playˇ¨ button for previewing the loudness of audio. Users can practice extracting tempo changes at the same time.
Beat
To input the tempo changes, left click mouse in the area of MIDI Panel. When the left button of the mouse is clicked, the ˇ§Beatˇ¨ button will turn green as confirmation.
Record Button
The tempo changes are recorded when users are ˇ§tappingˇ¨ (left-clicking the mouse) as audio is played. The most recent beat calculated in bpm (beats per minute) is show in the text area right next to the ˇ§Beatˇ¨ button.
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Chopin Prelude No .1 in C major, performed by Evgeny Kissin.
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Chopin Ballade No. 3 in A major (first 80s), performed by Evgeny Kissin.
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Program: PianistPaces.jar
Sound examples: Chopin Prelude No. 1 in audio and in MIDI
chinghuc@usc.edu