A Digital Video Recorder (DVR) records video to local storage devices, most commonly a hard drive. DVR can record analog video sources on-site or capture video from a digital source. DVRs can be connected to analog cameras via coaxial cables, enabling them to be accessed remotely. DVRs offer enhanced functionality like the ability to search recordings for events, or sort by time and date. DVRs can be configured to automatically replace older footage once storage becomes full.
DVR Hardware Features
- Mountable in a server rack
- Can include multiple source inputs (coaxial/optical)
- External monitor output
- I/O connection for tilt pan zoom (PTZ) camera
- Event notification from security devices
- Notification for connectivity issues
DVR Software Features
- Image capture by the user or triggered by an event
- Set resolution of recording by the user or by an event
- H.264 Video compression for higher resolution at lower bandwidth
- Video analytics such as dwell time, the direction of movement, and motion tracking
- Alarm, event, and time search functions
- Multi-channel audio recordings
- Archived footage
DVRs are limited to the physical number of input channels and are not upgradable. This makes them best suited for small businesses or home security systems. Network Video Recording (NVR) is a cloud-based video surveillance recording solution that can be upgraded at any time. Analog limitations mean DVR record is much lower quality than a network solution and also the video is always stored locally versus in the cloud.
Digital Video Recorders (DVR) advantages include:
- Analog systems are low cost and not technical
- Simple to operate
- Low data consumption since data is stored locally
Digital Video Recorders (DVR) disadvantages include:
- Lower resolutions, frame rates compared to network recording
- Requires local wiring and connectivity
- Installation can be complex with multiple cameras and locations
- Separate power supply required
- Not suitable for use with IP camera
- Only some models are capable of recording audio
With the cost of storage and cloud-based services coming down, NVRs have replaced analog DVRs for today’s security surveillance systems.