RETUNE is a real-time multi-pitch modification tool. It enables pitches belonging to the same pitch class to be shifted to any other pitch class. For example, all C notes in audio signal can be shifted to C#. In other words, RETUNE can be used to transform the key of any input audio signal to any other key.
Since each pitch class can be mapped to any other pitch class, mappings not only include major and minor input and output keys, but other scales, such as church modes or pentatonic scales. RETUNE does this in real-time, and likewise, the pitch mapping can be modified online during processing.
In addition to mapping individual pitches, RETUNE can correct each pitch by mapping notes to the nearest semitone, thereby eliminating inaccurate intonation. The API provides control over various parameters such as the sensitivity of the pitch detection, the detection of transients, and the smoothing of the pitch contour.