DVR vs NVR: Choosing a Recorder

Every surveillance quote starts with the recorder, because the recorder decides the cable, the cameras and how power reaches them. The DVR vs NVR question comes down to one thing: where video is turned into data, at the recorder or at the camera. This guide covers how each one works, where a hybrid unit fits, and how to pick for a retrofit or a new build.

How a DVR works

A digital video recorder takes the signal from each camera over coaxial cable and does the compression and recording itself. The NIST hosted Digital Video Quality Handbook describes the DVR as the recorder “commonly associated with analog video sources in the physical security industry.” Each camera lands on its own BNC input, so the back panel fixes the channel count.

Camera power is a separate job. The same handbook notes that cameras not powered over Ethernet, which includes every analog camera, usually take 12 VDC or 24 VAC. Most runs therefore use siamese cable with coax and a power pair in one jacket, fed from a power supply at the head end. The coax side follows the rules in our RG6 vs RG59 comparison for camera runs.

Current DVRs accept HD over coax formats as well as legacy analog, which lifts resolution well above the old standard definition picture without touching the cable. The formats are not interchangeable, so match each camera’s output to what the recorder supports.

How an NVR works

A network video recorder stores streams from IP cameras. The handbook defines it as a type of DVR “commonly associated with digital video sources that stream IP video.” Each IP camera has its own processor, compresses its video and sends it as network packets, so the recorder mostly stores, indexes and serves footage.

Cameras connect over Category cable to a PoE switch or to PoE ports built into the NVR. One cable carries data and power, and each run is limited to the 100 meter Ethernet channel. Sizing that power is its own task, covered in how to plan a PoE budget for IP cameras.

Because the cameras sit on a network, an NVR can record cameras across a building or campus that are not wired to it directly, as long as the network has the bandwidth.

DVR vs NVR side by side

Analog vs IP security cameras on the job

Analog vs IP security cameras is really a question about the building. If good coax already reaches every camera location, HD over coax cameras on a DVR can upgrade the picture with no new pulls, which matters in finished ceilings and occupied spaces. The handbook also notes analog systems suit small “closed” systems where remote access is not required.

IP cameras earn their keep when you are pulling new cable anyway. They offer more resolution choices, onboard analytics on many models, and one cable per camera instead of coax plus power. Before deciding, check these points:

• Condition of the existing coax. Test it before promising anything over it.
• Ceiling access, and the labor to pull new Category cable.
• Distance from each camera to the closet. Past 100 meters an IP design needs a switch or extender.
• Whether the owner wants remote viewing or ties to access control.

Where a hybrid video recorder fits

A hybrid video recorder accepts coax cameras and IP cameras on one unit. It is the usual answer for a phased upgrade: keep working analog cameras on the BNC inputs, add IP cameras on the network side, and replace coax cameras as they fail or as the budget allows.

Check how many IP channels a hybrid unit really supports, because many reserve only a few. The other path is an encoder, which the handbook says converts “video from analog cameras into multiple video streams that may be accepted by NVRs.” That lets a site move to an NVR now and retire analog cameras later.

Storage and retention

Both recorder types write to hard drives, and drive capacity sets how many days of video the site keeps. On an NVR the bitrate is set at each camera, so resolution, frame rate and codec drive storage directly. The handbook notes H.264 can cut file size “by more than 80 percent” compared with Motion JPEG.

Agree on retention with the owner before quoting, size drives with headroom, and use drives rated for continuous writing. Larger NVRs add drive bays and RAID support, so one failed drive need not cost footage.

Network security for recorders

An NVR puts cameras on a network, and any DVR with remote viewing is on one too. CISA and NSA list security cameras among devices that commonly contain default credentials attackers can use. Treat every recorder and camera as a network device:

• Change default passwords before the system joins the customer network.
• Keep cameras on the NVR’s own PoE ports or a separate VLAN.
• Avoid open port forwarding for remote viewing.
• Update recorder and camera firmware at handover and on service calls.

How to choose a recorder for the job

1. Survey the cable. Sound coax and an owner who wants minimal disruption point to a DVR or hybrid unit.
2. Count channels for today and for the next expansion, then add spares.
3. On new builds or open ceilings, run Category cable and go NVR.
4. On mixed sites, use a hybrid recorder or an NVR with encoders.
5. Confirm the PoE budget and storage before ordering.

Where to buy recorders and cameras

Bursma Distributing, established in 1947, sells only to dealers, installers and integrators. DVRs, NVRs and hybrid units are in the video recorders category, next to wired security cameras and wireless cameras in the Security, Surveillance and Control division. PoE switches are in network switches, and coax, siamese and Category cable in bulk wire.

Dealers see their own pricing and stock in Shop Online after logging in. New to Bursma? Open a dealer account, or call the Wyoming, Michigan branch at 616-831-0080 or the Columbus, Ohio branch at 614-299-9040.

Frequently asked questions