[peterkos]

Well, that's the thing -- when listening to any song, even if you know the pitches, it is impossible to know if there are accidentals or not depending on the phrase. If a 10-bar phrase modulates in bars 2-5, and you listen to bars 2-5, you may conclude the piece is in key X when it's just a modulation from the overall key of Y. This also implies the piece follows western common practice, or is even tonal in the first place. The difficulty of categorizing music is its ambiguity :)

[acmj]

The blog post criticizes existing software for their inaccuracy, but that is not their problem. The key signature of a particular passage may deviate from the overall key. I also wonder how they evaluate accuracy shown in [1] and what is the human accuracy in comparison.

[1] https://www.reddit.com/r/DJs/comments/hwlzyt/key_detection_c...