Name that tune

Ever heard a song on the radio that you liked but missed its name? A new technology called audio fingerprinting from Philips will help jog your memory Ð if you have a mobile phone that is.

All you do is hold your phone to radio's speaker for a few seconds while the song is played. The music is turned into a set of numbers, and sent to a database that matches it with the identifying code of virtually every song ever made. Within seconds, a text message naming the song, artist and album appears on the phone's screen.

Audio fingerprinting breaks down a musical piece into segments of 10 milliseconds and measures the energy of 33 frequency bands in each segment. The energies are transformed into a code and sent to a huge database at the other end.

Searching a large database is like finding the proverbial needle in a haystack. Instead of searching for the complete three seconds of code, the technology tries to match a small part of it. The preliminary results are then compared with the full fingerprint, which leads to the result you want in milliseconds.

Apart from just music recognition, the technology lends itself to a number of other applications. It can also be used to maintain personal music archives by either correcting metadata (e.g. providing a uniform artist/title format) or enhancing metadata (e.g. genre classification).

Audio fingerprinting can be used to build broadcast monitoring systems for copyright verification, commercial verification and people metering. Most existing systems have a large manual ingredient.

While testing is underway, there date has been set for its commercial release, so you'll just have to sit by the phone and hope your memory improves when that elusive song comes on.