Mobile phones name that tune
Making a hash of music
Philips has developed an m-commerce app which lets mobile phone users identify and buy a song playing on the radio.
It works like this: dial a service provider, put your handset near the source of the music for a few seconds and then receive the track title - with an offer to buy - via text message.
Developed by CryptoTec, a division of Philips Digital Networks (part of the company's consumer electronics group), the system uses a technique called Waveform Matching (also known as hashing or fingerprinting) to identify the tune.
Each track is given a unique fingerprint which can be stored in a database and cross-referenced with the sample sent in. CryptoTec gets this fingerprint by chopping up the song into 33 narrow frequency bands and measuring the energy in each band. The measurements are converted into hash codes which can be compared against the sample sent in from your mobile, matched and the answer dispatched back to you, reports New Scientist.
It doesn't help you if you hum along merrily to the song, realise the DJ hasn't named it and then scramble to put your phone next to the speaker... Unless you're listening to Virgin Radio (chances are it will play the tune again...and again...and again).
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