When we listen to an mp3---or a CD track, a mix tape, a record, even a wax cylinder---we're conjuring up the sound of a past performance. Now there's a new computer program that does the reverse, sort of: It takes an audio file and creates a piano-playing cartoon, using sound (or related bits of information) to animate a performance anew. The fingers of an expert pianist look relaxed as they tickle the ivories, never seeming overexerted or out of place. The computer program is designed to work on the same principle: It "listens to" a midi file and decides how the cartoon should finger each chord in order to put out the least possible effort. In addition to telling the active fingers which keys to press down, it also decides what to do with the idle fingers so that they are optimally relaxed and poised to play their next notes. Looking this at ease is a lot of work. Right now, the program creates an animated character to accompany a disembodied music file, but the UC Davis computer scientists behind the program think that it could help real-world musicians become more relaxed and therefore, more virtuosic. Would-be piano stars could use a motion-capture camera to record their practice, then compare the data to the program's ultra-relaxed formula for playing the same song to see whether their hands are in the best possible position. To play the piano better, the researchers suggest, it may help to chill out and watch some cartoons. [via New Scientist]