All DVR systems are not created equally. There are $10,000 economy Hyundai's, $100,000 luxury Mercedes and everything in between. It all depends on your needs and requirements. This is one of the reasons for the extreme differences in DVR pricing. It's what's under the hood that you pay for, but unfortunately without a Consumer's Guide to DVR's, it's difficult at best, for the user to understand the difference, until it's too late. You can buy a blender for the home for $25.00 but it is not the same as the $250.00 one at a restaurant. One is a consumer product the other commercial.
As part of your CCTV shopping preparations, decide how much quality you need out of your recorder. You need to decide how "good" the recorded picture needs to be, either for your own use later or possibly to use in court.
The size of the hard drive will dictate how much you can record. On the low end, an 80-gigabyte (GB) hard drive will store about five to eight days of full-motion video from one camera. Most of the time you will not be recording full motion, so this is much more than it might seem. For most businesses, spending a little extra to get 120 or 240 GB is a worthwhile investment. Units expand up to 1.2 terabytes (1,200 GB), which can store many cameras' worth of data for long periods of time.
You will also need to consider how many cameras you want to connect to the DVR. Keep your future expansion needs in mind - buying a higher-grade model to get more inputs and more storage space can save you considerable money in the future. The DVR will also function as a multiplexer, putting up to 16 cameras on one display and allowing operators to call up any one image for closer inspection.
One thing you need to be careful about when analyzing specifications of a DVR with respect to "frames" or "images" per second is:
- The total number of frames/images per second for the entire card to be spread across all cameras (cumulative total).
- The total number of frames for each individual channel
- The maximum frame capacity of the hardware not taking into account software switching, simultaneous functions, etc. (rated hardware capacity)
- Display speed
- Recording speed
- A combination of all of the above
There are an infinite number of ways of presenting these numbers, many of which are misleading.
Remember that 30 frames per second is real-time / real motion video, but that is for a single video stream. So if you want to record 4 cameras simultaneous, all in real-time/real motion video, you need 120 frames per second and its full unshared resources.
To drill down even further you have to question at what resolution is the real time image being displayed. Many systems can only record real-time if the resolution is lowered. The frame rate issue is a very tricky one. The fact is the speeds that manufacturers quote are usually the “maximum” obtainable, meaning under ideal conditions, and does not take into account anything else the PC, software, or video card might be doing. In other words it's like the MPG sticker on your new car – good luck trying to get that mileage; maybe downhill in neutral with a strong tailwind.
- First select the fps (frames per second) that you wish to be displayed/recorded for each camera. We recommend a minimum of 5fps for basic security applications. 30fps is optimal and is the normal frame rate for watching TV images from camcorders, VCR's, DVD's, etc.
O.K. 1-3fps - Slow Time Lapse Video
Good: 5-7fps - Time Lapse Video
Better: 10-15fps - Near Full Motion Video
Best: 30fps - Full Motion Video
- Second determine the number of cameras that you will need. Keep in mind that if you wish to add more cameras in the future, you will need to have extra inputs available.
- Third make sure that the system software has all of the features that you require and need in order to successfully operate your new system.
In order to make choosing a system easier for you. We have created a Frames Per Second (FPS) Demo for you to view. Simply select the link at the top of the page. This way you understand how your system will preform depending on the number of cameras you choose and the total number of Frames Per Second of the DVR System.
Glossary of Terms & Technical Specifications
Choosing A Digital Video Recorder
Frames per second Demonstration
Live Remote View Demonstration
Choosing A Surveillance Camera
