network video recorder (NVR)

There are several approaches to storing video. The analog recording videorecorder, personal video recorder( PVR), digital video recorder( DVR), and the network video recorder (NVR), which also exists as a network-based personal video recorder( NPVR).

Network Video Recorders record digital video data streams that are transmitted over IP networks. To do this, the camera signals are digitized, compressed and packetized, and transmitted using IP protocols. Unlike digital video recorders, which must be located near the camera, NVRs are location-independent and store the digital video data stream transmitted using IP protocols. NVR recorders are powerful personal computers with Serial ATA( SATA), USB and eSATA interfaces and correspondingly large hard disks that may well have several terabytes( TB). They are connected to the local network and can simultaneously record several digitized video signals from video cameras or IP cameras. The recording of the data streams in MPEG-4 is done on hard disk.

Multi-channel Network Video Recorder (NVR) VioStor, Photo: i-o-c.de

NVRs are often connected as a cluster, which allows some NVRs to record while others play back what is recorded. Users who have access to the NVRs can dial them up via the local area network or even wide area networks and retrieve video streams. NVR clusters are often redundant, mirroring video data to other hard drives. If one NVR recorder fails, another can take over recording. This redundancy means that no video data is lost.

NVRs are used for recording and playback of video data, but also for video surveillance of buildings, facilities and living spaces.