7 June 2010 1 Comment

DVR, Quad Processor, or Switcher – Differences and Preferences

DVR, Quad Processor, or Switcher – Differences and Preferences

by Jennifer Spears
Security System Design Engineer

I thought we’d get back to basics for a minute and discuss the options available when you have more than one surveillance camera at your business. I’m going to be talking about 3 different pieces of equipment. I’ll be talking about them in feature order from least to most, and also some extra goodies they can be used for.

First a disclaimer…These items will all be discussed assuming they have BNC video inputs. There are different kinds of video connections for different kinds of cameras. Some are directly compatible, some can be adapted, and some should be placed in the garbage and never thought of again.

Now down to the good stuff.

1. Switcher – This device is most commonly a 4 or 8 input box that can be plugged directly into a 110V

Meaning it has a standard connection that plugs into the wall, and it can see from 1 up to 8 cameras sequentially. A switcher does just what the name implies. It shows the cameras full screen and can switch from one to the next to the next. You can turn off unused camera inputs, so the empty screens won’t show at all.

A dwell time is settable for these boxes normally from 1 to 5 seconds. That is the amount of time a picture will remain on screen, before it changes to the next one.

These devices have NO recording capabilities at all – just viewing. Such as on a boat when you’re just using several cameras as back up assistance but you don’t need to record any of them.

Switchers are also great for providing extra duties, but normally not on their own. You can use them with multiple location monitors in conjunction with DVRs. Such as the front of a convenience store when the clerks need to be able to see several cameras full screen, but you don’t want the DVR out in the open. Even in a second office of a self storage facility.

You can also use these to show customers that they are safe, or the flip side – they are being watched. Two examples of this, is a customer seeing themselves on a monitor at a pharmacy counter, or in a grocery store when you are waiting to check out. If they aren’t doing anything wrong they will feel protected with eyes in the sky, and if someone shows up to do you harm – hopefully they will mind their P’s and Q’s and go down the street and leave your business alone.

You will use a standard BNC monitor with these devices, or you can normally adapt them to work with the Audio/Video (A/V) input on most TVs.

One extra ability these boxes can be used for is if you need just one extra camera on a 16 channel DVR. Don’t want to spend another $500 for a 4 channel DVR, when you need only one – no fear! Just connect your two least important cameras to the switcher, and then connect the switcher into the 16th video input on your DVR, and you can switch between 16 and 17. This could save you some money, or get you out of a pinch, but it will also eliminate your ability to record via motion detection on your DVR, because a DVR looks for pixel changes on the screen. Each time the picture changes, the DVR will see it as motion and begin recording. This will result in that channel recording full time.

2. Quad Processor – These boxes are the next step up from switchers. What is really great about them, is that some models can take 4 cameras, but others can actually take up to 8 cameras and switch back and forth between two 4 camera (quad) views. Many of these use a regular 12V DC power supply, instead of direct 110V. If you order a quad, as they are normally referred to, just make sure that it comes with the necessary power transformer or pigtail to connect to existing power.

Quads have all the same functions and features as a switcher does. But a quad can also show you up to 8 cameras on a split screen. One camera will show in each quadrant. Many of these devices offer choices of viewing a single camera, a single camera with one or two picture-in-picture (PIP) insets, two cameras, 4 cameras, 8 cameras, or other functions, depending on the brand and model of Quad Processor. Keep in mind though that most Quad Processors have real time views in Quad mode, but may exhibit jerkiness, or slow frame rates when in 8 camera mode.
Most will come with a remote control so they are very easy to operate.

The examples used for the switcher can also be performed by the quad processor as well, but you’ll just be able to see more cameras simultaneously. These work well at larger offices, warehouses, parking lots, etc. that need to be able to view specific cameras – at multiple locations.

Quads are also commonly used in conjunction with a DVR to provide selected views to a remote monitor. This is handy for almost any business, such as a restaurant that needs to see the outdoor cameras by the back door before venturing out at night, or at any business that needs to feed certain camera views to specific areas or employees.

Again this device has no recording capability.

3. Digital Video Recorder (DVR) – (Not the PC-based version, but a Stand-Alone unit, sometimes referred to as Embedded or purpose-built version) Now for the big boy in the industry! This box is a stand alone, souped-up version of a time lapse VCR mated with a very stable, hack-proof multiplexer and recording processor.

Now before you ask – NO it is not a PC based recorder. Some do not use a keyboard, but most of them can use a VGA style monitor and even a USB mouse. The software for the unit itself resides on the processor chip on the motherboard. So if a hard drive goes down, instead of replacing it and then having to reinstall all of the operating system and software on it, and then being forced to set up the system from scratch – purpose-built DVRs allow you to simply replace the hard drive, format it, and you are back up and running immediately. Besides the rock-solid stability, this is one of the tangible advantages of going with a Stand Alone DVR.

These devices have a hard drive or multiple hard drives inside that the video is recorded to. These systems can be set up to record all the time, or when motion is detected, or when another event is detected. Better still, each camera can be set to record by any of these methods – on a camera by camera basis. In other words, one camera can be recording full-time, while another can be set to only record upon motion.

Most DVR’s will have multiple monitor outputs, audio capabilities, sensor/relay input and output options, and even pass-thru connectors for each camera that can send feeds to other devices, such as a switcher or quad processor.

DVRs compress the video coming from your cameras before it is placed on the hard drive. It saves on space, but the better models don’t alter the quality of the video enough for the naked eye to see it. There are two main compression methods that currently offer the best picture along with the smallest file sizes – MPEG4 and H.264. These compression methods are normally proprietary to each DVR manufacturer and some need special software to view the cameras remotely or to watch copies of backed up footage from the system itself. Each method has different advantages and I’m only touching on this right now. I will cover more on compression methods in a future article.

Depending on the features you are looking for on a system, it is best to purchase a system from a manufacturer. They designed it, built it, and know their equipment better than any retailer. Most DVR manufacturers make several different varieties, so you need to make sure you talk to a sales person or design engineer that can ask you the right questions, determine what you need, and pair you with the correct system. One with everything you need, but not one that has so many extra features that will confuse you or that you’ll never use.

Most DVR systems will have different capabilities on how to make a copy of footage from the DVR. Some only have USB stick capabilities, others can use a CD or DVD drive, and many have all, or a combination of these options. Again find a company that can make it easy and recommend which one is right for you and your business.

DVRs, at least the ones worth their salt, are remotely accessible and remotely controllable. This means you can connect to them either on the same network at the location, or if you set up your network correctly, offsite through the internet. As long as you have high speed internet access, DSL or cable modem, and someone that can set it all up – that is all you need.
Most DVR’s feature private video feeds that are password-protected, and DO NOT charge you a monthly fee for you to be able to access YOUR system.

The right supplier will assist you in getting your DVR system up on the internet and remotely. This is one of the hardest things to accomplish, and the one thing most customers call in frustrated about. It is just hard, and if you don’t connect to your network and routing system on a day to day basis, you’re almost guaranteed to have to ask for help.

I did not discuss multiplexers here, because DVR’s have dropped in price so much over the last few years, that a good DVR is now cheaper than a multiplexer – and the DVR has a built-in multiplexer included.

So, whether you need to simply view cameras and don’t need to record them, or you need to view and record – a switcher, quad processor, DVR, or sometimes two or more of these devices used together – will fit the bill.

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One Response to “DVR, Quad Processor, or Switcher – Differences and Preferences”

  1. Jack Gregas 28 September 2010 at 9:10 pm #

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