The difference in resolution between the two devices has been narrowed by advancements in analog high definition over the last five years. You will probably find that security systems based on DVRs are priced lower than NVR systems. An appealing value of DVR systems is the lower price point, but what are the tradeoffs? We need to break down each of the components of a DVR device to address this.
Camera Type – Analog
Analog surveillance cameras, better known as CCTV cameras, must be the cameras a DVR system uses. The camera is responsible for much of the cost savings found by the use of a DVR device. Although in your home surveillance system, you can mix and match cameras, there is less versatility in the type of cameras you can use for DVR systems.
The analog cameras in a DVR system stream an analog signal to the recorder, which then processes the images. Compared to an NVR device, the benefit of this scheme is the reduced complexity required of the camera.
Cable – Coaxial BNC Cable
Via a coaxial BNC cable, the camera attaches to the DVR recorder. Although the use of coaxial cable does not seem necessary, there are some limitations to it:
- As the coaxial cable does not provide the camera with power, two cables are actually used in one cover, a power and video cable. Each end is separated by cables to provide separate functions. As such, near a power outlet, you will need to mount your DVR recorder.
- Coaxial cables’ size and rigidity can make installation more difficult. The diameter of the coaxial cable is wider than that of Ethernet cables used in NVR systems, which can make running cables in small spaces more difficult. Coaxial cables appear to be more rigid as well, compounding this problem.
- However, you can use the same cable to link your new device if your property has existing coaxial connections to a previous protection system.
- The audio is not supported by normal coax cables. A variant that needs an additional RCA connection, but a DVR has a limited number of audio input ports even with these, so that only a small number of cameras can capture audio.
- After around 90m, the picture quality on the coaxial cable will begin to deteriorate, which may restrict the ability to expand the security presence outward. Lower quality cable, at shorter lengths, can result in signal loss.
DVR recorders rely on a hardware chipset known as an AD encoder to process the streaming of raw data from the camera into readable video recordings.
When it comes to the recorder, DVR systems have numerous specifications as well. Specifically, the user has to connect every camera directly to the recorder in a DVR device. The NVR system, by contrast, only allows each camera to connect to the same network. In a DVR system, the recorder also doesn’t supply the cameras with electricity. In order to allow cameras to operate, each camera link will need a splitter that supplies power.
Flexibility of framework
In terms of camera form and mounting choices, DVR protection systems are less versatile than their NVR counterparts. Whereas NVR-based systems can incorporate both wired and wireless security cameras, only wired security cameras can be used for DVR systems. There are also less flexible mounting solutions for DVR systems, since coaxial cable routing can be more difficult in tight situations and each camera needs a power outlet.
Production of Image & Audio
As we’ve discussed, the cameras relay analog video directly to the recorder through the coax cable in DVR systems and images are processed at the level of the recorder. Compared to NVR systems, the analog signal results in a lower quality picture. Often, coaxial cables do not send an audio signal natively, and DVR recorders typically have a small number of ports for audio input.