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What is a DVR (Digital Video Recorder)?
A digital video recorder (DVR) is basically a computer that allows you to save images to a hard drive.
The technology is continuing to progress and DVR systems are becoming faster and less expensive. A DVR will also take the place of a Time Lapse VCR, Quad and Multiplexer.
This reduces the overall cost of a video security system.
The main advantages to a DVR are that it typically has a better picture than a VCR and you don't need to maintain it with new tapes and less time to review.
How is DVR better than VCR?
A VCR has a low resolution level. This causes the pictures to be grainy, and the video tapes degrade and decompose over time.
With a DVR you don't need to change tapes or touch the system at all for long periods of time. The only moving part is the hard drive and if a part breaks, you can easily replace it.
DVR vs. VCR
| Item |
Analog |
Digital |
| Recording |
Analog Image |
High Resolution Image |
| Recording Media |
VCR Tape (Frequent Change) |
High Quantity Hard Disk |
| Continuous Recording |
Image Quality gets worse when recorded for a long time |
Unlimited Reuse |
| Image Search |
Takes long time to go through |
Search within one second |
| Image Quality |
Low Image Quality |
High Image Quality |
| System Maintenance |
Need have space to store tapes |
No maintenance is required |
| Image Transmission Function |
No function |
Transmission possible |
| Cost for Maintenance |
Recorded Tape, Head change for VTR and its following cost to maintain |
No cost for maintenance |
| Detection Area |
To a distance where cable can reach |
No distance limitation |
| Print |
Separate equipment is needed |
Output of High quality screen image, remote output and transmission, internally installed |
| Recording |
Record without any option |
Record by Sensor (Eliminate unnecessary recording) |
What should I look for in a DVR?
There are several important things to look at when buying a DVR.
The first is the interface. Is it easy to operate? Does it look as though someone put thought into how the operator uses it? The second would be the reliability of the system.
They also use up resources that may cause the system to lockup if not maintained. Our systems offer a reset everyday at a time specified by you to eliminate this problem. Also, on some of our boards a watchdog wire is connected to Reset on the computer.
This way if communication is lost with the video board ( it locks up) the computer will automatically reboot itself. Another thing to look at is the frames per second (fps). This relates to how many pictures it will take in a second. Real time recording would be about 14 fps on each camera. Only the most expensive systems over $10,000.00 would even come close to this. The technology is just not there yet. But 3 fps and up on each camera is very acceptable.
You can see a clear picture even though it does have some hesitation in the recording. Motion picture quality is 24 FPS, and our DVR System can record up to 30 FPS, per camera.
What is the best camera to use with a DVR?
Most cameras are analog and must be converted to a digital picture.
Any standard camera will give you a nice picture because again, the technology can not take any real advantage in picture quality at this time.
How do I see pictures from a remote site?
You can dial-in on a modem which is slow but can display 1 or 2 frames every 5 seconds. Better is a DSL or cable modem connection which can generally display 1 frame per second.
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