Glossary
NVR vs DVR vs VMS: what is the difference?
Definition
A DVR (digital video recorder) records analog cameras, converting their signal into digital video. An NVR (network video recorder) records IP cameras, which encode video themselves and stream it over the network. A VMS (video management system) is software that manages many cameras and recorders, often across sites, with shared users, alarms, search and evidence export.
NVR vs DVR vs VMS explained
DVRs and NVRs are recording appliances, usually tied to one location and often managed one box at a time. A VMS is the management layer above them: it can record directly from cameras or work alongside existing recorders.
Many organizations run a mix: older analog cameras on DVRs, newer IP cameras on NVRs, and a VMS to bring them into one view.
OrionAlerts
How OrionAlerts handles it
OrionAlerts does not require existing recorders to be removed. The Nebula OS device layer connects supported IP cameras and recorders through ONVIF, RTSP and vendor SDKs, so an NVR can keep recording while OrionAlerts adds video management, AI video analytics, camera health monitoring, asset records and AMC workflows. Support for each recorder model is confirmed during solution design.
Explore Video Management System (VMS)FAQ
NVR vs DVR vs VMS: common questions
Can a DVR record IP cameras?
A traditional DVR cannot; it only accepts analog camera inputs. Hybrid DVRs, often sold as XVRs, accept HD-analog cameras plus a limited number of IP cameras, which helps when an estate is migrated gradually. For an all-IP system, an NVR or a VMS recording to its own server is the usual choice.
Do I need an NVR if I have a VMS?
Not always. Many VMS platforms record directly from IP cameras to their own servers and storage, so a separate NVR is optional. Keeping existing NVRs can still make sense when they work well, are already paid for, or hold footage that must be retained. The right answer depends on the estate and the design.
Does OrionAlerts work with existing NVRs?
Yes, where the recorder is supported. OrionAlerts connects IP cameras and recorders through ONVIF, RTSP and vendor SDKs, so existing NVRs can stay in place and keep recording. Older or analog cameras are evaluated individually to find a suitable stream or integration path, and each model is confirmed during solution design.
Related terms
Video management system (VMS)
Software that connects cameras and recorders so operators can view live video, record, play back and export footage from one place.
Read moreONVIF
An open industry standard that lets IP cameras, recorders and video software from different manufacturers discover and work with each other.
Read moreRTSP (Real Time Streaming Protocol)
A network protocol used to set up and control live video streams from IP cameras and recorders.
Read moreCamera health monitoring
Continuous checks that cameras, recorders, storage and network links are online, streaming and recording, with alerts when they are not.
Read more
See it on your own cameras
Book a walkthrough of OrionAlerts on Nebula OS, from camera connection to alerts on the dashboard, mobile app and email.