DVR

A digital video recorder, commonly abbreviated DVR, is an electronic device that records video in a digital format to a storage medium, typically a hard disk drive or solid-state drive. DVRs are used in two broad contexts: home entertainment systems for time-shifting television programming and security surveillance systems.

In consumer television applications, a DVR connects to a television (and often to one or more tuners or set-top boxes) to capture broadcast or streamed content. It records programs to storage, supports scheduling and automatic recording, allows pausing and rewinding live TV, and may provide apps or interfaces for playback, guide data, and streaming to mobile devices.

In security applications, a DVR receives video from cameras via coaxial cables or network links in hybrid systems. It digitizes (if needed), compresses, and stores footage on disks, often with multiple channels (4, 8, 16 or more). Features commonly include motion detection, event-based recording, search by time or camera, and remote viewing through web browsers or mobile apps. Some models support RAID storage and export of video to USB or network shares.

DVRs differ from network video recorders (NVRs). DVRs traditionally process and encode video on the device from analog or SD streams, while NVRs generally handle digital streams from IP cameras, with encoding performed by the cameras themselves or in the network. Hybrid devices can manage both.

The concept emerged in the late 1990s as digital recording replaced videotape in broadcast and surveillance applications, evolving with increased compression efficiency (MPEG, H.264/HEVC) and integration with consumer electronics and cloud services.