Modul8 is described as 'VJ is a revolutionary MacOS X application designed for real time video mixing and compositing. It has been designed for VJ and live performers'. There are more than 10 alternatives to Modul8 for Windows, Mac and Linux. The best alternative is Vidiot, which is both free and Open Source. Other great apps like Modul8 are Isadora (Paid), Resolume Avenue (Paid), VDMX (Paid) and LiVES (Free, Open Source).