what would be really cool if audacity could listen to music and transcribe it to notes, a little bit like shown here:
Automatic audio transcription is extremely difficult for computers.
I agree that it would be a nice feature, but I’m also aware that it would be a very big project requiring a huge amount of development work. There’s already some features that can help (such as “track spectrogram view”, and in particular the “Pitch (EAC)” algorithm), but going from there to fully automatic note transcription of polyphonic music is a long and difficult journey. Currently none of the Audacity developers are working in this area.
I can log your interest in this feature, but developing such features will take years, even for a team of professional developers working on this and nothing else.
if audacity could listen to music and transcribe it to notes
This is a cousin to the request that Audacity “convert” music into MIDI.
It would, but it’s not likely to happen because it’s insanely hard for any software to “listen” to music and tell accurately what the notes are. That’s what you have to do for either of these jobs.
Matt Thibeault in the YouTube video says he’s not interested in directly converting pitches to piano notes as much as he wants to: “Use my ear and my eye to compare the notes that I do know with the ones that I don’t know.”
So he’s using his eyes and ears as the analysis engine, not trying to force the software to do it. You can use the Audacity analysis tools to dig out one or two notes, but I suspect that’s not what most people want. Most people want a fully formed MIDI song or completely formatted printed music.
Even software designed to do that doesn’t do that very well.