For a while, I’ve thought that someone should set up an Internet site to let you find the name of a piece of music you’ve heard. Apparently I just wasn’t looking hard enough – today, I stumbled across Musipedia.org, a kind of Wikipedia for music.
My plan was that the site would allow you to enter the tune on some sort of virtual keyboard, ignoring tempo and paying attention only to the relative up and down frequency differences. It turns out that Denys Parsons proposed a similar but more robust system for encoding tunes in his 1975 book, The Directory of Tunes and Musical Themes. This is now known as the Parsons Code.
Using it is pretty straightforward – just type an asterisk for the first note, then for each following note, type U if it goes up, D for Down, or R if it repeats the previous note. With three possibilities for each letter, a short sequence of just 20 notes can record more tha three billion distinct tunes. It is also not affected by errors in pitch or timing.
Once you have the Parsons Code for your tune (or at least a brief snippet), you just need a big database to search against – which is where Musipedia comes in. They only have about 30,000 tunes so far, but over time I expect this to grow. Certainly, it had no problems identifying Rossini’s William Tell Overture and Puccini’s Gianni Schicchi – Oh, mio babbino caro.