 Many times, he or she will use a camera and camera operator to take live video feeds of the dancing crowd and superimpose them on a video of something else to give a novel effect.A top end mixer option is the Pioneer SVM-1000, which has preview screens, switchers, video FX, and audio FX, all in a four-channel mixer.A standard setup can be the Pioneer DJM-800 with a VSW-1 Switch and a three-screen monitor.