rave.dj is a site that allows you to create mash-ups or mixes of multiple songs automatically. They are closed-source and it can only be operated through their website.
Are there any existing open-source alternatives to this? I have a project I'd like to implement it into, but if one doesn't exist I'll develop my own one (I have a pretty good idea as to how it operates).
It doesn't have to do additional functions, such as also creating a mash-up for each song's corresponding music video, but it should be able the create coherent mash-ups of at least 2 songs.
Edit: Any license is fine for me, my project is personal and non-commercial.