Search for music by drawing a picture of it
I've spent the weekend hacking on a project at Music Hack Day Montreal. For my hack I created an application with the catchy title "Search for music by drawing a picture of it". The hack lets you draw the loudness profile for a song and the app will search through the Million Song Data Set to find the closest match. You can then listen to the song in Spotify (if the song is in the Spotify collection).
Coding a project in 24 hours is all about compromise. I had some ideas that I wanted to explore to make the matching better (dynamic time warping) and the lookup faster (LSH). But since I actually wanted to finish my hack I've saved those improvements for another day. The simple matching approach (Euclidean distance between normalized vectors) works surprisingly well. The linear search through a million loudness vectors takes about 20 seconds, too long for a web app, this can be made palatable with a little Ajax .
The hack day has been great fun, kudos to the Montreal team for putting it all together.