Users can sing, whistle or play a few notes on a musical instrument into their PC's microphone. The key to the software is its ability to digitise your ditty and then extract a sequence of pitch and timing data that can be usefully compared with actual musical pieces. The idea is that after you've entered your tune, the search engine scours a database of tunes, looking for matching pitch and timing information.
Timing is a non-precise parameter.
Even a pianist cannot play a piece the same way twice. Our algorithm has been designed to accommodate this fuzziness. But there's another problem. At the moment there aren't any databases of relevant musical information. He predicts that scholars will use it to compare compositions, and lawyers to settle copyright battles.