A key decision in designing your video surveillance security system is to decide how you will store the video footage your cameras recorded. DVR, NVR, cloud, embedded, VMS, windows-based server, Linux based server, analog cameras, analog HD cameras, IP cameras, network cameras.... I am tiring myself out as I name all the different types of video surveillance and security cameras systems available. What do these terms all mean and why are they important to you?
We’ve been in the physical security industry for over 15 years and it seems like every year things get more complex. New technology emerges, old technology changes, and there is a fit for each one in different scenarios.
First, you need to understand how your cameras record. This is the best place to start because it sets the stage for the rest of your system. All recorders perform the same function but differ in how they record and type of cameras they use.
DVR = Digital Video Recorder
This term came out in the early 2000’s and it was the replacement to the VCR. Prior to DVR’s, cameras connected to a VCR and tapes needed to be changed every 12-24 hours. In order to have extended periods of video footage, you needed endless amounts of tapes. The DVR allowed you to record onto a hard drive and when the drive was full it would re-record over the oldest data always leaving you with a set amount of recording days (typically 20-30 days). DVR’s are still around today, and the term is used very loosely, especially by people who have been in the industry for a while. They come in 4, 8, 16, 32, and even 64 channels. When they came out, the most common cameras were analog cameras and in simple terms this basically meant that the camera needed to plug directly into the DVR via coaxial cable and into a power supply via a low voltage power cable. The maximum resolution that you could achieve at the time was VGA or 640x480 or 0.3 megapixel. Digital Video Recorders process the video at the recorder, use analog cameras and is typically a wired system.
Windows based DVR vs Embedded DVR
When the first digital video recorders came out, it was basically a video capture card – that allowed you to physically plug in a set number of cameras i.e. 4, 8, 16, 32 – installed into a computer running Microsoft Windows. You would install the recording software and voila you would have what we refer to as a Windows based DVR. Shortly after the invention of the DVR we started to see what was referred to as embedded DVRs. An embedded DVR looked very similar to a common household DVD player. A black box which had a set number of inputs on the back, 4,8,16, etc., but they did not run on Windows. These recorders ran Linux which made them a simpler device and lacked the features of a Windows based DVR. The main difference between the two was the feature set, embedded lacked the power required to have features beyond simple motion-based recording and video playback. Systems with large numbers of cameras (20+) would more often require a Windows based DVR.
NVR = Network Video Recorder
This term started to appear in the early 2000’s as well but became the norm by 2008 and more so after 2010. The main purpose of an NVR is to record IP cameras over a network. Although the first IP camera was released in 1996, it wasn’t until 10-12 years later, around 2008, that IP cameras started to take over. An IP camera no longer required you to run a cable from the camera directly to the recorder. You can plug an IP camera into a network switch and then record it anywhere on the network using recording software. Typically, the software would sit on a dedicated Windows based computer (or server), the server would be on the same network, and you could find the camera using its IP address in order to setup and record streams from that camera. When NVRs came out, you would need to purchase a camera license (or software license) for each camera that you wanted to record. The software is often referred to as a VMS or Video Management Software. NVR systems encode and process the video data at the camera, then stream it to the NVR recorder which is used for storage and remote viewing.
VMS = Video Management Software
The early NVRs almost always came equipped with a Video Management Software or VMS. VMS providers such as Milestone and Genetec, the pioneers in Video Management Software, focused mainly on developing their platform. VMSs were and still are, arguably, the most powerful and feature rich way to build a security camera system. If you want to record anything more than 20 cameras at one site, with higher than 3MP resolution for each camera, you should strongly consider a Video Management Software.
A few advantages of a video management software are:
1. Higher variety of camera manufacturers to choose from to add to your system
2. Stronger integration with other building automation systems such as access control, alarm systems, etc.
3. More advanced search/save or live monitoring functionality, especially with large numbers of cameras
4. Advanced user management options
5. Strong fail-over & redundancy options
6. Network friendly tools to help you manage video traffic
The VMS providers spend a lot of money making sure their software is secure, up to date, able to record with the major security camera manufacturers, can integrate with other security products, and that their software is running smoothly. With a VMS you can expect better camera integration, faster and better compression/storage settings, and easier management settings.
Shortly after the introduction of the NVR and VMS, the embedded NVR started hitting the market. Like the embedded DVRs, this was a DVD player look alike. They came, and still come with, less features compared to a video management software, and most often run on Linux. These “boxes” are generally limited in hard drive space and more importantly camera count. The biggest difference between the embedded DVR and embedded NVR is the deceiving specifications for the camera counts. When you move into IP cameras and require an NVR to record your cameras, it can get quite complicated on how to choose a recorder. The embedded recorder manufacturers will often refer to their units as 4, 8, 16, or 32 channel recorders. The problem is that IP cameras can come in 1MP, 2MP, 3MP.... all the way up to 8, 16 and 29MP. The manufacturer will say “can record upto... X MP” but what they do not advertise is that the higher the megapixel the lower the count of cameras that can be recorded. With an embedded DVR, it was straight forward because the resolution was low and almost always consistent (VGA being the highest). So, when you purchase a 16-channel embedded DVR you could record 16 analog cameras. However, with an NVR you need to pay attention to bandwidth and throughput. There is a calculation that you would need to run which involves: Number of cameras, resolution per camera, projected amount of motion per camera, camera compression, number of people viewing the cameras at once and how many cameras they will be viewing, If you’re not careful you can easily overshoot or undershoot the type of NVR you are purchasing.
Analog HD (AHD) Recorder
The arrival of IP cameras pretty much killed the analog video surveillance market. Just when everyone thought it was dead, manufacturers came out with analog HD. In simple terms, Analog HD refers to cameras that connect directly to the DVR using an analog signal. You cannot put cameras on a network and record them, you must run a cable from the camera directly to the DVR. The DVR can be networked for remote viewing, but unlike IP cameras which can sit anywhere on your network, analog HD cameras need to run back to the DVR. This was a huge benefit because now you can keep your existing analog infrastructure (cable, power supply, etc.) and just change the cameras to an HD camera (upto 8MP now). You still need to be careful with throughput on the DVR but you do not need to move into an IP camera system, with an NVR, in order to get HD cameras. These systems tend to be slightly cheaper and are usually a perfect fit for smaller systems of upto 16 cameras (even though larger systems are available)
The difference between all these systems come down to the cost, how the data is transmitted, and type of cameras. NVR and VMS systems tend to have better picture quality, as well as easier installation and increased flexibility. However, they also tend to be quite a bit more expensive than comparable DVR systems. For businesses looking for a relatively straightforward security system, a DVR system will most likely be sufficient, especially if your property is already wired for a coaxial cable from an existing security system. At the end of the day, the deciding factor will be based on the specific security needs of your property.
The video surveillance market has evolved significantly from the early days of VCRs to the emerging AI cloud era. Understanding each component of your video surveillance system is essential in evaluating security systems. To learn more about the other basic components of a video surveillance system click here.
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