Nice work! I have built a similar system for an ios app called Pacemaker DJ, it might be worth checking out for comparison/inspiration. I learned a couple of lessons from that project:<p>- some music is super easy to mix (minimal house) while others are basically impossible (punk rock)<p>- vocals in two tracks simultaneously always sounds bad/annoying. I ended up including a vocal detector in the algo.<p>- incompatible musical keys can sound really bad in some cases, in other cases just fine. I think it depends on the saliency of the notes, among other things.<p>- very few care about nice long beatmix transitions apart from djs. IME djing is mainly about playing good music and keeping a flow/vibe.