Digital Video Recorders (DVRs) record one or more video feeds to disk for later playback. Commonly, the video feeds are composite video from CCTV (closed circuit TV) video cameras. Stand-alone DVRs usually record analog cameras. A PC-Based DVR is a computer with, sometimes, additional hardware installed. They can record analog cameras like the standalone DVRs (thus the extra hardware), and some record IP (network) cameras over their existing network interface.