I still can't understand how that feature works. They stated that everything is done locally on the device, so privacy is not an issue. But how can they host a huge catalog of songs fingerprints without blowing the storage? Are they only saving the top charts?
It's definitely not just the top charts. Notably it has picked up when someone near me was playing Chopin on a piano as well as the occasional KPop tune my girlfriend is listening to.
My guess is it supplements the data with songs from your Google Music and youtube history.
They only store a catalog of the most popular songs. (Where 'most popular' is determined by your geographical location). This catalog is periodically updated.
I think the Pareto principal kicks in hard here. If it stores the top 20,000 songs as the other comments suggest then I expect that would include the vast majority of music you’d come across.
at 3.3kb it's only about 64mb to store 20,000 songs. If they periodically update that (in the background, on wifi, etc) you'd likely never know. It's basically noise when OS updates are multi-gb.
According to a friend who works at Google, they only store a catalog of ~20k popular songs that updates periodically. Fingerprints are small, so an archive of that size isn't too big.
