There are many factors that need to be taken in to account when choosing the right digital video recorder. To begin with, you will need to consider how many channels you will be needing. Every channel is a camera input and just about every DVR comes with 4, 8, 9, or 16 channels. There are some that only come with a single input, but for the purpose of this discussion let’s assume that you are looking for a multi-camera set up.
With the basic four channel setup, you can cover enough area by choosing wider angled cameras, however, you may want to cover more area so choosing an eight channel recorder will enable you to do this. One reason for doing this would be because perhaps there are too many blind spots in your four camera setup. A general rule of thumb in determining how many cameras are required is by walking around the areas that you want covered as this will give you a rough idea. In saying that, while having more channels might greatly benefit you or your business, having too many can create problems too. If you are only wanting to keep an eye on a small area, such as an office, you may not need more than four cameras so buying a digital video recorder with eight or more channels would be a waste of money.
Furthermore, the size of the hard drive will be a factor. While it is almost impossible to say how much time you can record with any hard drive, you can pretty much estimate that at maximum settings on a typical DVR you get one hour per channel per gigabyte. So with an eight channel recorder you are using eight gigabytes per hour on the highest setting and so on. However if you lower the resolution, record only on motion, or lower the frame rate you can increase recording time to a week or even a month before it’ll start recording over itself. An advantage of motion detection recording is that you won’t have to waste time watching hours of useless footage to see if something occurred or not. It’ll give you the time and date stamp of when something important occurred allowing you to go to the event, whether ir be a flying bird or someone that is scoping out your business.
The next factor that you need to consider is network-ability. A lot of the current recorders are set up to be accessed remotely so you might want to think about whether you want to be able to view your cameras from another office, at home or perform remote backups. By doing this you won’t need to purchase additional monitors to view all of your cameras, instead, each PC workstation is able to access it on their computers.
Moving on to audio, some cameras have built-in microphones or you can opt to use external microphones for those that don’t. This all depends on whether your DVR handles audio. Most will be able to support anywhere from 1-4 channels of audio, which is in correlation to that specific camera i.e. channel one video is linked to channel one audio and so on. Next we will be looking at how video is offloaded. DVRs will often have built-in CD or DVD burners and other will use a USB port to offload to a flash drive. Unfortunately with current capacities available in flash drive, this has rendered the CD/DVR option obsolete when it comes to DVR reporting.
Something else to consider when choosing your digital video recorder is the IPS or Images Per Second and is usually given as the combined total for all of the channels. When you are looking for a DVR you will probably notice them noting as having, for example, 120 IPS for an eight channel recorder. By dividing the number of channels by the IPS you will have a maximum recording rate of 15 IPS or half speed. One thing to be aware of is that advertisers may try to confuse you with Live View Images versus Recorded Images. Just remember that you are not skipping or losing time, you are recording less frames each second. The disadvantage of this is that it makes the video less fluid, but you will save on hard drive pace and increase recording time. In saying that, Real Time DVRs are more expensive and unnecessary.