Mixxx is an open source DJ tool designed for both professional and semi-professional users. It is free and runs on all major desktop operating systems. Furthermore, Mixxx has a number of key features to help the DJ in the live mix: Beat estimation, parallel visual displays, and support for many DJ input controllers. Mixxx reads most popular sound formats, including MP3, Ogg Vorbis, Wave and Aiff. It can be controlled through the GUI and with external controllers including MIDI devices, joysticks and more.