Digital Recorders

Digital Video Recording

Have you been thinking about getting a digital video recorder (DVR) but not sure just how the system works?

Maybe you think this technology is changing too rapidly and it's not worth buying - maybe you think DVRs will become the next 9-track player. Well, technology is certainly changing rapidly but DVRs are here to stay.

A Digital Video Recorder is very similar to the VCR – just with a lot of exciting extras that make is very user friendly!  Basically, a DVR is a hard drive with a few special functions.  (just like your computer)  The hard drive resides in a box with a computer board, memory, and a central processing unit. On the back of the box are a series of jacks. These jacks allow the hard drive to receive input through a coax cable (from your cameras.)

The DVR then records the input received from the cameras and saves it to the hard drive.  When you decide you want to watch what the cameras have recorded – you access the hard drive and send the signal via cables to your monitor.

Because the DVR is very similar to a computer – the amount of memory that the DVR has, is important in every application.  A larger hard drive will allow for longer recording. 

Digital Video Recording

Most DVR’s can record at least a week of video surveillance with 4 cameras – then after the week – the DVR will record over the information automatically.  The larger the hard drive space on the DVR – the longer recording time is available.

Unlike a VCR because all the recording on a DVR is done to a hard drive – you do not have to watch hours of video to see what happened at 5:00 PM, July 1, 2005!  You can pause, rewind, or fast forward through the video, quickly and effortlessly.  The DVR records all activity with a time and date stamp – which means it is very easy to locate when you are looking for something.

The other great thing about a DVR is that you can also connect to the internet.  Using a static IP address, you can view the video that the cameras take from home, from another office, or from a holiday in Mexico!  You can watch what is going on 24 hours a day! 

Connecting the DVR to the Internet also allows for the DVR to sound an alarm when something happens at the location the DVR is set up in.  The DVR can send you notification via email – it can also work with your security system and trigger a traditional alarm device. 

You can schedule the DVR to choose specific times of the days of the week to record data.

Digital Video Recording

             Office                   Showroom                  Warehouse

The DVR allows a person to Export Video – if you have Internet Capability – you can export the image or video to another location – or, if you require it – you can print the image with date and time information.

Some Digital Video Systems come with very few options while others have many.  You can get a DVR that does not have the ability to go onto the Internet, while a high end DVR will have the ability burn a CD – just like your computer to take the information with you.

Benefits of a Digital Video Recorder

• Viewable from anywhere in the world (if desired)
• Crystal Clear Video
• High resolution
• High frame rates
• No expensive multiplexer required
• No tapes to wear out
• No tapes to change (automatic recycling of storage space)
• Able to trigger alarm zones
• Able to send email notification which includes snapshot
• Fast Forward & Rewind are INSTANT
• Records to industry-standard MPEG4 format - play back on any modern computer and many newer DVD players
• Can be scaled up to be used for webcasting/netcasting events over the Internet to hundreds or even thousands of viewers
• Advanced P/T/Z Camera Control
• Practically-unlimited expansion of recording time (basic package provides several thousand hours' worth of storage - 300:1 compression)
• Can be configured to require password!!

Digital Video Recording

A Digital Video System works only as well as the cameras you have on it.  Some people pick Black and White Cameras, while others prefer Color Cameras – and then for applications at night – people pick Infrared Cameras.

Color cameras generally require higher levels of lighting than their monochromatic (B/W) counterparts. Color produces a more natural, richer image than black and white and may keep the operator's interest for longer periods of time. It also makes it easier to detect subjects.

For example, with a color system a viewer can easily distinguish a red car from a green one, while on a black and white system both cars would appear a similar shade of grey.

In retail applications, a color system can help security personnel identify shoplifters and their clothing more easily and convincingly. Color accuracy is extremely important in gambling casinos, where hundreds of dollars can ride on the ability to recognize the difference between maroon chips and red ones. 

While the use of color cameras is growing, black and white cameras continue to offer some distinct advantages. Black and white cameras are better suited for extremely low light situations. The ability to capture good quality images in low light situations increase the cost of both black and white and color cameras. Before purchasing cameras, you should consider the crossover points between lighting costs and camera costs. It's possible that low-light cameras will cost less than paying to increase the lighting level of a parking lot!

The main performance factors are:

The Type and Quality of the Imaging Chip in the camera
CCTV surveillance cameras produce images using CMOS or CCD (Charge Couple Device) chips. Tiny, very low price CCTV cameras usually use CMOS technology, produce poor quality images and have very poor light sensitivity. Higher quality CCTV cameras use CCD technology. The size of the CCD chip is normally 1/4", 1/3" or 1/2". As a rule of thumb, the larger the size, the higher the quality of the image produced and the higher the price. However, higher density 1/4" and 1/3" CCD chips can now produce as good an image as many 1/3" or 1/2" chips.

The Make of the CCD chip in the camera
Not all CCD chips are equal, even with the same specifications. Quality varies by manufacturer. Panasonic and Sony are generally recognized as producers of the best CCD chips. All CCTV cameras supplied by Certified Alarms use CCD chips from these two manufacturers.

Number of TV Lines
The number of TV lines in the camera image is a measure of picture resolution (sharpness). The larger the number of TV lines, the better the resolution and hence, overall picture quality. Over 400 TV Lines is generally considered good resolution while over 500 TV lines is considered high resolution

Light Sensitivity
Sensitivity ratings are generally given in "lux" (a light level measurement). The lower the lux number, the lower the light levels at which the CCTV camera will produce an acceptable image. In other words, the lower the lux level rating, the more light sensitive the camera. B/W cameras generally have lower lux level ratings than color cameras (i.e. B/W cameras will produce acceptable images in lower light conditions than color cameras). 0.003 Lux of light (the equivalent of the amount of light available on a starlit but moonless night).

Digital Video Recorders vary in price, hard drive space and installation difficulty - please call for prices.

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