1. Mapping MIDI to the Spiral Array: Disambiguating Pitch Spelling Elaine CHEW Yun-Ching CHEN

2. MIDI Pitch Structure pitch spelling chord ident. key-finding Time Structure beat tracking meter induction segmentation style recognition pattern processing Applications automatic transcription computer analysis of music categorization / retrieval expressive performance Motivation Pitch Spelling using the Spiral Array 2/8

3. Pitch Spelling Each pitch read from the MIDI file will correspond to two or three letter names. Rowspelling1(index)spelling2(index)spelling3(index) 0B#(12)C(0)Dbb(-12) 1C#(7)Db(-5)B##(19) 2C##(14)D(2)Ebb(-10) 3D#(9)Eb(-3)Fbb(-15) 4D##(16)E(4)Fb(-8) 5E#(11)F(-1)Gbb(-13) 6E##(18)F#(6)Gb(-6) 7F##(13)G(1)Abb(-11) 8G#(8)Ab(-4) 9G##(15)A(3)Bbb(-9) 10A#(10)Bb(-2)Cbb(-14) 11A##(17)B(5)Cb(-7) * (index) refers to index of pitch in Spiral Array. Pitch Spelling using the Spiral Array 3/8

4. Illustrative Examples Opening bars of Beethoven’s Piano Sonata, Op.109 Bars 25 ½ - 33 ½ of Beethoven’s Piano Sonata, Op.109 Default { B, G, Bb, Eb, Ab, Db, Gb, Cb } Spelling 1 (initialize c.e. at C major) { B, G, Bb, Eb, Ab, Db, Gb, Cb } Spelling 2 (initialize c.e. at g# minor) { B, F#, C#, G#, D#, A#, E#,F## } Pitch Spelling using the Spiral Array 4/8

5. Literature Review Interval Optimization Approach - Automatic Pitch Spelling: From Numbers to Sharps and Flats Emilios Cambouropoulos (2001) Evaluated on 8 complete piano sonatas by Mozart and had a success rate of 96.2% Preference Rule Approach - The Cognition of Basic Musical Structure, David Temperley (2002) Many possible interpretations are considered; Each rule expresses an opinion as to how well it is satisfied by a given interpretation, and Opinions are combined to yield the preferred analysis. Evaluated on Kostka-Payne corpus and had success rate 98.8% Pitch Spelling using the Spiral Array 5/8

6. Our Method c.e. acts as proxy for key context Select spelling closest to c.e. Bb A# c.e. Pitch Spelling using the Spiral Array 6/8

7. Results Piecenotescorrect spelling% correct Beethoven Op.79 (3rd movement) 1375137499.93 Beethoven Op.109 (1st movement) 1516144395.18 TOTAL2891281797.44 Pitch Spelling using the Spiral Array 7/8

8. Discussion Types of Errors: Algorithm’s ignorance of linear motion Insufficient sensitivity to key changes Linear motion in Op.109 resulting in spelling error in bar 10 (circled). Spelling error (circled) in bar 20 of Op.79 because the c.e. had not yet detected the E minor context. Pitch Spelling using the Spiral Array 8/8