Ready to learn some more? Good! Last time we talked about the things to think about when buying cameras, and we even took some shortcuts. This time, we’ll cover a little bit about the technology and some specs you should look at, as well as talking a little about storage.
Going Analog in the Digital Age
A few years ago, the surveillance industry pivoted toward IP (Internet Protocol) video after users had spent decades building out analog infrastructure in the form of wiring and storage systems. Analog video used the same sort of signal system that wired television transmission did, hence the term Closed Circuit Television (CCTV). Every surveillance camera was essentially sending a TV transmission to a monitor and/or recording device on a closed circuit. IP, or network, cameras work the same way a web cam does. They send and receive signals over the Internet or a local network instead of the old coaxial cables used by analog systems. IP cameras could transmit video in higher definition, and web interfaces added functionalities like pan/tilt/zoom control without the need for a specialized, often expensive, control board. Remote viewing of individual cameras became simpler. It looked like analog systems would be going away.
Recently, though, analog has been making something of a comeback. A few manufacturers continued to build and sell cameras for use in legacy installations so customers could replace devices that were damaged or failed without needing to replace entire systems. And there were plenty of them out there. Hybrid video recorders capable of recording from both analog and networked devices hit the market, allowing for piecemeal upgrades, one device at a time. And then HD Analog protocols caught on in the market. These cameras can send HD video, 1080p being the highest quality generally available at the time of this writing, over coaxial cable.
Why would anyone want to use analog cameras? There are two good reasons: cost and cables. HD analog devices tend to cost less, sometimes significantly, than equivalent IP devices. This reason can make them attractive on its own. The second is for those legacy installations mentioned earlier. If a company has a campus-wide system in place, it can be extremely costly to remove the coaxial wiring that already exists and then replace it with network cabling, on top of purchasing all new cameras. There’s also a perception that CCTV is inherently more secure than IP systems. This isn’t necessarily the case, because most video recorders are still connected to the Internet, or at least as capable of it as network devices. Network systems can be just as secure by keeping them on a LAN and off the larger Internet.
Which is better? You’ll have to decide for yourself, but lacking pre-existing infrastructure, the advantages of IP cameras in versatility and control will likely make them a better choice.
Wi-Fi? Why Not?
Wireless video transmission has been in use for years. It started in analog cameras using open analog transmission, which wasn’t secure, then moved to digital transmission, in which a camera and receiver would be paired. Wi-Fi has become the preferred method of wireless communication, thanks to its wide adoption and user familiarity. It’s generally more secure than older technology, but has a shorter range. Thanks to things like Wi-Fi repeaters, though, they’re a viable option in a lot of installations.
Wi-Fi cameras are often referred to as “wireless,” which can be misleading. A wireless camera will still require power, which will almost always require a wire of some sort. Wireless just means video is transmitted wirelessly.
Don’t Get the Jitters
Frame rate, measured in frames per second (fps), can be overlooked, but is an important spec to keep in mind. It’s a measure of how many individual frames the camera transmits, or records, every second. The human eye is generally capable of perceiving about 30 images in a second, so 30 fps is often referred to as real-time recording. Higher frame rates can be useful in recording objects moving at high speeds. If you’re monitoring the entryway of a parking lot, for example, you want to capture at the highest frame rate possible.
Many cameras have customizable frame rates. To conserve bandwidth and storage space, you can dial them down. By sending only 15 fps over the network, you’re using half the bandwidth. This is a perfectly viable solution in many situations—but weigh the consequences. Lower frame rate video can be “jittery,” and fast-moving objects will appear blurry.
Keeping and Controlling
A lot of IP cameras have onboard storage capabilities and built-in analytics functions, like motion detection or line crossing, which used to require a separate device. This means that they can function on their own. This doesn’t mean that they should be. SD card recording, the most common media cameras use, is limited, and you don’t want to have to go out and retrieve the card if there’s ever a problem.
You’ll probably want a Network Video Recorder (NVR), the successor to the DVR, which had a similar purpose. NVRs record and store video. The number of cameras an NVR can support is expressed as channels, one per camera. They store video to an HDD or SSD the same way a computer stores data, but surveillance drives themselves are specially designed for stability and constant up-time.
An NVR can add more than just storage to your surveillance system. It can offer control functions for your camera, letting you pan and tilt, activate heaters or fans, or zoom in on multiple cameras through a single interface. Additionally, they can add a bevy of post-recording analytics features to your system.
In large-scale installations, above 24 cameras or so, a server running network video software (NVS) will take the place of an NVR. NVS programs are available for smaller installations, and they may make sense for you if you have custom needs that a dedicated recorder with built-in firmware can’t meet. Many will back up data to a NAS (Network Attached Storage) device, or over the Internet to a virtual server in the cloud.
Breakdown, or TL;DR
Wow! That was a lot of information! And we didn’t even talk about a lot of specs, features, or options. So, let’s break this down for the folks who scrolled down to see how long this was.
Your choice of camera/s will be based on where you’re installing it/them. This will help you decide on form factor, weather resistance, light sensitivity, and resolution. Then, decide how you want to view and store your video. Assuming you don’t have existing infrastructure, you’ll probably want a network camera. So, do you want to record to an NVR, another dedicated device, or cloud storage.
Answer those questions and you’ve got a good start. If you need help, the B&H team is available to help you. There’s a lot to wade through on our website and every situation is different. We’ll help you put together a system that suits your needs.
Click here if you missed The Basics, the first of this two-part series.
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