A Digital Video Recorder (DVR) is a device that records video in a digital format to a disk drive. DVRs made specifically for CCTV Security Surveillance System applications record video signals from security cameras. The information, once captured, can be stored and able to be viewed multiple times. Many DVRs are designed to record audio as well. DVRs provide features and services, such as searching video by time/date or camera, that surpass the simple recording of video images. A DVR also offers control over quality and frame rate or overwrite security footage that is deemed no longer crucial, allowing disk space use to be maximized. In some DVR security systems, remote control and access to security footage is possible by connecting the DVR to either the internet or a LAN network. Some of the latest security digital video recorders include video analytics software and firmware, enabling functionality such as following suspects or objects throughout your surveillance system to the detection of abandoned objects.

Security DVRs may be categorized as being either PC based or embedded. A PC based DVR's architecture consists of a PC with operating system and a video capture card designed to capture video. An embedded DVR is designed as a single unit with its operating system and software contained in the firmware or read only memory