A Digital Video Recorder(DVR) is designed to record video signals from closed-circuit cameras for detection and documentation. DVR’s have evolved into sophisticated devices that exceed the simple recording of images of VCRs. You may search for an event by time, date, and camera, instead of watching all the video for a particular event. There are many variables including the frame rate, hard drive, and number of cameras. As a DVR records it records over the oldest data first, allowing you to always have the newest data. DVRs usually fit into 2 categories PC-based or Embedded. A PC-based DVR has been modified to Surveillancecapture the images, and an embedded DVR is designed as a digital video recorder.
A Network Video Recorder(NVR) is used in IP (Internet Protocol) Video Surveillance and uses a software program that records video in a digital format to a hard drive, or other storage device. The NVR uses a network instead of a traditional direct connection to the camera. Video on a DVR is encoded and processed at the DVR, whereas video on a NVR is encoded and processed at the camera itself, then streamed to the NVR for storage and viewing.