Skefis – a Symbolic (midi) Key Finding System

SKeFiS is a symbolic (Musical Instrument Digital Interface) key finding system that incorporates pitch spelling, key finding, and a cumulative window strategy for determining key. After selection of the window to be considered, key recognition is considered a compound process: one of first determining the spelling of the pitches from numeric pitch information (MIDI), then extracting key from the pitch name information. By combining pitch spelling and key finding, we not only get the pitch class number of the tonic of the key, but also its letter name, and an appropriate key signature for the piece. The window size (length of music) is determined from the test data provided by the contest organizers. Figure 1 depicts the key finding process from MIDI input to key output, including the length parameter selection based on the sample test data provided. The compound process of pitch spelling and key finding is embedded in the system and outlined by dashed boxes.