Short answer
A DVR is the recorder for analog (coaxial cable) cameras and converts the picture to digital itself. An NVR is the recorder for IP cameras and records the picture that comes from the camera in digital form over the network. Your cameras decide which one you buy; if you want to use both together, a hybrid recorder (XVR) is chosen.
How does a DVR work?
A DVR (digital video recorder) takes the picture coming from analog cameras over coaxial cable, converts it to digital, compresses it and writes it to disk. Here the cameras only produce the picture; the recorder does the heavy part of the work. Each camera is connected to a separate BNC input on the back of the device.
Unlike older devices, new DVRs support HD analog technologies such as AHD, TVI and CVI. For this reason, using an old DVR with an HD analog camera is often not possible. If you are changing the camera, check that the DVR supports that camera's technology and resolution.
A DVR's channel count is fixed: 4, 8, 16 and so on. When the channels are full, adding a new camera needs a larger device or a second DVR.
There is usually also a network port on the back of the DVR. This port is not for the cameras; it is for connecting the device to the modem to watch from a phone and make remote settings.
How does an NVR work?
An NVR (network video recorder) takes the digital picture sent by IP cameras over the network and writes it to disk. The work of compressing the picture is done in the camera. With an NVR, the cameras do not need to be in the same place; it is enough for them to be on the same local network. This way, cameras on different floors of the building can record to a single NVR through the switch on that floor.
Some NVRs have PoE ports on the back. IP cameras plugged into these ports get both their power and their connection from a single cable, and no separate switch is needed. It is a practical solution for small businesses and homes. As the number of cameras grows or when the cameras are spread out, separate PoE switches are used.
Besides the NVR's channel count, there is also an input bandwidth. This value shows how much data per second the device can take in and record. If the total data of high-resolution cameras exceeds this value, the device forces the channels down to lower quality.
When does a hybrid recorder (XVR) make sense?
Hybrid devices record both analog and IP cameras at the same time. They suit people who want to keep an old analog system working and add IP cameras at new points. While the coaxial cameras in a school building keep working, IP cameras can be added to a newly built gym.
How many IP channels a hybrid device supports varies from model to model and is generally fewer than the number of analog channels. On some models, the number of IP channels can be increased by turning off analog channels. Before buying, settle how many IP cameras you will connect and at what resolution you will record.
Expert note: A hybrid device is a transition solution. If the analog cameras reach the end of their life and IP cameras will take their place, choose a model with enough IP channels from day one so you do not run short of channels later.
What to look at when choosing a recorder
Whether it is a DVR or an NVR, check these values in the datasheet. They determine how much the system can grow later and how many days of recording it can keep.
- Channel count: room for today's number of cameras plus a few cameras to be added later.
- Number of disk bays and each bay's largest supported disk capacity.
- Highest supported camera resolution and, on an NVR, the total input bandwidth.
- H.265 compression support: longer recordings fit on the same disk.
- Number of PoE ports and total PoE power (on NVRs with PoE).
- ONVIF compatibility: so that IP cameras of different brands can be connected.
- Human and vehicle detection, and being able to search by them.
Disk choice and recording security
A disk fitted in a recorder works under a different load from a computer disk. It writes without a break all day and often sits in a closed, hot cabinet. For this reason, disks that manufacturers make for security recording systems, designed for continuous writing, are preferred.
In devices with more than one disk bay, recordings are written to the disks in turn, or they can be distributed using a method called RAID so that the recording is not lost even if one disk fails. RAID is not on every device, and a shorter recording time is obtained from the same disk capacity. This option should be considered if losing the recordings would have serious consequences.
Do not put the recorder on a shelf anyone can reach. A thief tries to take the recorder first, not the camera. A locked cabinet or a separate room matters as much for protecting recordings as the choice of camera.
Power outage and temperature
If the recorder shuts down in a sudden power outage, it both stops recording and can damage the disk. Connecting the recorder and the PoE switch to a UPSkeeps the system up in short outages and lets it shut down properly in a long outage. In an analog system, the camera adapters also need to be powered from the same UPS.
In Şanlıurfa’s summers, a recorder sitting in a closet with no ventilation gets very hot. Heat is one of the main factors that shorten disk life. Putting the device in a ventilated cabinet or a cool room, and cleaning the dust out of its fans, are simple but effective measures.
Which one should I buy?
If your cameras are analog, you buy a DVR; if they are IP, you buy an NVR. If you are building a system from scratch, the choice is really a camera choice; we explain this in detail in our article comparing IP and analog cameras. If you want to keep a mixed system running for a while longer, a hybrid device acts as a bridge.
When choosing a recorder, also consider how easy it is to use. Rewinding and searching footage, exporting an incident, and viewing from a phone are everyday tasks. A device with a confusing interface makes it hard to find the footage when an incident happens. If possible, see the device’s interface and mobile app before you buy.
If remote viewing will be turned on, make sure the device’s software is still being updated by the manufacturer. Change the factory password on day one, and create separate users with view-only permission for the people who will do the viewing. Recordings are personal data under Law No. 6698 KVKK , so you also need to limit who can access which recording.
During the site survey, Desa Bilişim checks whether your existing recorder is compatible with the new cameras, and if it needs to be replaced, states the reason in writing.
Frequently asked
Can I connect an IP camera to a DVR?
A standard DVR does not accept IP cameras. Hybrid recorders (XVR) can also record a certain number of IP cameras. If you will use only IP cameras, you need to choose an NVR.
Can an IP camera of a different brand be connected to an NVR?
If both devices support the ONVIF standard, picture and recording generally work. Advanced features such as human detection often work fully only with a camera of the same brand.
Does a camera record without a recorder?
Many IP cameras can record to a memory card inside them. Because the card is small, and because the recording is gone when the camera is stolen, a recorder is preferred as the lasting solution.
Is your recorder suitable for the new cameras?
We will review your current device’s model and your camera plan, and recommend a compatible recording solution with a written quote.
