How does Shazam work?

[caesar]

I know we have superb digital experts here, so I was wondering if anyone has any idea how Shazam, the song identifying app, works.

Thanks in advance

 

[Steve Williams]

It is remarkable. Have you looked at Soundhog

 

[Bruce B]

I know we have superb digital experts here, so I was wondering if anyone has any idea how Shazam, the song identifying app, works.

Thanks in advance

Every song has a digital pattern/fingerprint.

 

[amirm]

The way it works is that it has a database of songs each with an "acoustic fingerprint." It is called that because the fingerprint needs to be how we hear a song. A simple fingerprint of say, what the bits look like will not survive compression, transmission, pick up by a phone's noisy mic, etc. So the songs go through various transformations to attempt to extract their true audible characteristics irrespective of the actual bits. There is a trade off here with respect to how much of the song is needed and how much computing resources are used. The more lax, the more chances of false hits. The less lax, the more requirement for resources.

So process wise, the sample is extracted (e.g. recording your phone's mic), it is usually normalized to get rid of volume differences and then the processing performed to extract the fingerprint. The finger print is a set of "vectors" (values) that can then be compared to the library in the cloud database. Once a hit is found, it is displayed.

 

[Keith_W]

I have found that Shazam doesn't work too well with classical music. With two different versions of a particular piece - say, Beethoven's 9th ... Shazam won't be able to tell you who the conductor was.

 

[Bruce B]

I have found that Shazam doesn't work too well with classical music.

SoundHound doesn't work that well either with Classical.