Visualizing Hip-Hop Melodies (2016)

One of the most educational and interesting explainer videos I've ever seen is Vox's "Rapping, Deconstructed". Please consider this required watching, even if you have no interest in hip-hop music: https://www.youtube.com/watch?v=QWveXdj6oZU

After you watch that, I suspect you'll hear this Kendrick Lamar track with new ears: https://www.youtube.com/watch?v=_ZTYgq4EoRo

I know that while I am still very much a jazz/rock person, those videos expanded my perception of what was musically possible. No hyperbole on my end.

(This isn't related to hip-hop or melodies.)

I have absolute pitch; I can tell the pitch of any musical note I hear without any reference at all. I can also produce any pitch within my vocal or whistling range without a reference. This all comes completely naturally to me, and I don't have to think about it. Listening to this rap song, I noticed something strange.

The article talks about the melody of the song, but the rapper isn't singing. Of course, his rapping voice still has a pitch but it's actually not obvious to me what note he's "singing". If I listen very hard, I can still pick out the pitches of his notes (like how he centers on D). However, it is much much harder for me to tell the pitch of a speaking voice (or rapping voice) than a singing voice. This leads me to believe that there is a separate, functionally discrete part of my brain dedicated to processing music.

It also perhaps explains why I don't like rap music that much; it feels like my brain processes it as though it is spoken word rather than music, creating a somewhat strange and unmusical experience.

This is really cool -- I know I tend to enjoy certain songs that share certain characteristic flows, this would be a fun way to sort of "quantify" and organize a music library. I wonder if Spotify uses a technique like this as a heuristic for their song suggestions.

Is there an open source alternative for Melodyne?