Last article we talked about the very most basic features of a camera that you should be looking for and now we’re going to talk about the heart of a home security system- the home security camera DVR! DVR stands for digital video recorder, which really means, a machine that organizes all your surveillance information for you and files it away for your use when you feel compelled to really want it. Often with home security systems we spend so much time thinking about the cameras and motion detectors we over look the essential parts of the system like the DVR. Let’s spend a little time today talking about the DVR and it’s basic features.
If the camera is the eyes of the system the DVR is the brain, it makes all the decisions about what to do with the information that you are gathering through 24-hour surveillance. The DVR really provides two main services that you are going to need to pay attention to as you look to buy your system:
- Displaying the footage that you watch through a live stream.
- Compressing and recording that footage.
There are different features of the DVR that allow you to enjoy the quality of the aforementioned capabilities and these are what we’ll explore in this article.
PC Based or Stand Alone
Your security system will function based upon the DVR machine operating it, these machines can be either PC based or stand-alone devices. The difference between PC and stand-alone DVRs manifests in the kind of machine driving the operating system of the DVR. In a PC tower a computer has been devoted to running programs that provide you with your surveillance display, your compression and recording. In a stand-alone device you’re going to have actual hardware performing the processes. PC towers are more compatible with the integration of other programs such as facial recognition, but they’re more easily hacked and if something goes wrong internally you can lose everything. A stand-alone device enjoys the security of functioning mechanically, this means if you have hard-drive failure you only lose footage since the actual processes are run by the hardware itself. Additionally stand-alone systems are more durable and harder to hack.
Resolution and Compression
Resolution of a DVR is connected to the information it is receiving from the camera. You want to make sure that you get a camera that is compatible with the DVR you choose to use. There are two different resolutions you want to think about as you select your DVR. The first is the resolution of display the second is the resolution of recording.
When it comes to displaying footage nearly every camera and DVR can run real-time footage in HD resolutions of 720p or 1080p so don’t settle for less than that. The DVR simply has to be able to think and process the footage for display. But when it comes to the actual preservation of that footage you’re getting into different topics. For the DVR to record anything and have enough space to continue recording for a long time it is required to COMPRESS the information found in the thousands of frames of footage.
Compression can be explained as a matter of discarding redundancies. When the DVR starts compression it literally searches through every frame, finds the redundancies or the spots where nothing changes from frame to frame and throws it away. This of course costs you quality in resolution when you want to review the footage later. You want a DVR that will be able to search the frames, discard the redundancies and still keep your footage fairly high in resolution, the best compression rates are H.264. The good news is there are systems available to you today that actually have the ability to record images in 1080p- that’s cinema quality! Whether or not you actually need an image that good, if a DVR can do that you’re certain to find a machine that provides you with a quality image even in review right?
Looking for a DVR and camera system is mostly a matter of finding what works for you. Analog, IP wireless, HD-SDI, there are many different options for broadcasting, but if you understand what a DVR offers and what features a camera should have you can weed out what you don’t want and then search until you find the best!