chromaprint

Well sure, a songs database is important. But song databases like https://acoustid.org/ exist, which let you look up songs that share the same audio "fingerprint" (https://github.com/acoustid/chromaprint). You need the full track to make that fingerprint. Shazam can take only a tiny snippet, and can guess quite accurately just from that snippet. By comparison to AcoustID, which is also a song database (with an entirely different purpose) we can say that the "main ingredient" is Shazam's system for identifying songs from short snippets.

I recently ported [Chromaprint](https://github.com/acoustid/chromaprint/) to Zig. If there's interest I would be happy to extract it into a separately maintained package. For now it lives [here](https://codeberg.org/andrewrk/player/src/branch/main/player/...). I also did a [semi-related talk about this](https://www.youtube.com/watch?v=SCLrNqc9jdE). For context, Acoustid is a MusicBrainz-adjacent service for figuring out the MusicBrainz ID of a song based on the sonic content alone, even if it has been distorted or compressed. Chromaprint is the logic for computing an Acoustid given a song as input.