A Brief History of Surveillance Video Recording Technology
You will quickly learn that all DVR’s and surveillance solutions are not alike. Quality, performance and reliability vary widely. It’s not what the manufacturers and installers do tell you, rather what they omit. The object of this guide is to make sure the products and solutions you specify meet your required overall objectives.
Prior to the digital age surveillance video was recorded on videocassette recorders (VCR’s). Since videocassettes don’t store more then several hours of video on a traditional VCR, time lapse recorders were used. The time lapse recorder may record a single frame of video each second or even less, instead of 30 frames per second, which is live motion. With a single frame of video being recorded you only had to change the tape once every 4-5 days. The only problem there was:
- someone had to remember to change the tape when it ran out
- since only a single frame or less was recorded many times you missed details of an incident
- since the tape was recorded over and over the video quality became poor very quickly
- tapes would break and jam
- machines wore out quickly
- you had to go to the location to see the tape and could not do it remotely
Since you only wanted one video cassette recorder, the question was how am I going to record multiple cameras? After all, if I need 16 cameras was I going to have to buy 16 time lapse recorders? The answer was no. A piece of hardware known as a multiplexer or a quad was used, which would take all the video images and put them all on a single screen.
The quad or the multiplexer was a box with multiple video inputs on one side and a single video output on the other side. The problem there is imagine how small the images are and trying to see what happened, when an image takes up 1/16th of a screen; with no way to blow them up; good luck!
DVR technology for security began in the early-to-mid 90’s with mechanical-type devices. They typically were operated by remote controllers and buttons or dials on the DVR box itself. Easy to operate, their functions and keys were similar to a device users were already familiar with; the VCR. Unfortunately, due to technological limitations, early DVR’s were not reliable, had limited features, offered poor quality video recording and were not powerful enough or designed properly to provide solutions that could address managing large amounts of cameras and video. Customers required more capable and reliable systems, which resulted in the introduction of PC-based DVR’s.
The PC-based DVR brought enhanced features and were programmable, but the early models were plagued by inherent reliability problems and still did not have the requisite robustness in order to manage anything of substantial size.
Today, both PC based and non-PC based DVR’s and related solutions are much improved over their early predecessors. Considerable advances in digital video technology and equipment have opened as many doors to users as they present challenges and quality issues for manufacturers.
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