[Terribledactyl]

I don't think this problem is bound by absolute frequency resolution, the tightest distance between two notes on a typical piano is ~2hz and if you assume a doubling between octaves you're at <90 notes. The temporal changes and relative chord progressions probably give more info.

[Despoisj]

Thanks for your insights! I agree that log/mel spectrograms could be even more detailed and effective, and could be used with the SoX patch discussed here https://sourceforge.net/p/sox/feature-requests/176/.