A DVR takes an analog video signal and digitizes it in the box. An NVR takes video the camera has already digitized and sent over a network. That one difference sets the cable, the camera, the resolution and what the system can do about a person in the frame, so it is worth understanding before anyone quotes a camera count.
A DVR
A digital video recorder connects to analog cameras over coaxial cable, one run per camera, with power on a paired conductor or a separate supply. Modern analog is high definition — the HD-over-coax formats carry 1080p and beyond — but the camera is a sensor and nothing more: the recorder does the encoding, the motion detection and the storage. The strength of a DVR is the cable. Coax runs a long way, and a building that already has it in the ceiling from an older system can be brought up to HD by swapping the cameras and the recorder without opening a wall.
An NVR
A network video recorder connects to IP cameras over ordinary Ethernet cable. Most NVRs carry power over the same cable, so each camera is one Cat5e or Cat6 run to the recorder and nothing else. The camera does the work: it encodes its own video, often at 4K, runs its own analytics — a person crossing a line, a vehicle in a lane, a face at a doorway — and the recorder stores what it is sent. A single run is limited to roughly 300 feet before a switch or an extender is needed, which is a real constraint in a warehouse and no constraint at all in a store.
Which a new installation gets
An NVR, nearly every time, for four reasons.
- Resolution. IP cameras at 4K are ordinary now; analog tops out lower and the picture softens over a long coax run. When the point of the system is to read a face or a plate, that gap is the whole case.
- One cable. Power and video over one Ethernet run, terminated with a standard connector, on cable an electrician or a network contractor already understands.
- Analytics in the camera. Detection that ignores a swaying tree and flags a person means fewer false alerts on your phone, and because it is done at the camera the recorder does not have to be replaced to get it.
- The building's future. Ethernet in the ceiling serves access control readers, intercoms and wireless access points as well as cameras. Coax serves cameras.
The exception is an existing coax installation in a building where running new cable is expensive — hard ceilings, finished walls, a leased space where the landlord limits what can be opened. There, an HD-over-coax DVR with new cameras is a sound upgrade, and we recommend it when it is. Hybrid recorders that take both coax and IP cameras let a system move over one camera at a time.
Remote viewing
Both kinds offer it, and on a current recorder it works the same way: an app on your phone, live view and playback, alerts from motion or from the camera's analytics, and clips you can export. The difference is under the hood. Older recorders required opening a port on your router to the internet, which is how a great many cameras ended up publicly visible; current recorders connect outward to the manufacturer's relay service, so nothing is opened inbound. Either way the recorder needs a wired connection to your network, and your internet upload speed sets how many streams you can watch at once from outside. If the building's internet is poor, viewing from home will be too, and no recorder fixes that.
Storage and the rest
Both record to internal hard drives, and both keep footage for a period set by how many cameras, at what resolution and frame rate, on how large a drive — a week to a month is typical for a small business. Both should sit somewhere locked, because the recorder walking out of the building is the footage walking out of the building.
The third option is worth knowing about: cameras that record only to a cloud subscription with no recorder at all. Simplest to run, priced per camera per month for as long as you keep them, and dependent entirely on the internet connection. For two cameras on a small shop it can be the right answer; for twelve across a warehouse it rarely is.
We design around what the building has and what you need to see, and put the camera count, the cable runs and the recorder in a free written estimate. The walkthrough is same-day when the schedule allows.