DVRs (Digital Video Recorders)
DVRs have replaced the VHS tape video recorder.
DVRs are the most important part of your security camera system. They have the hardware and software to, among other things, control recording, playback and remote viewing of your system.
There are 4,8,16,24 or 32 channel systems. This means you can connect, record and control 4,8,16,24 or 32 cameras at once.Features to look for:
You should expect a DVR to have the following:H264 video compression (explained later)
A mouse
A remote
A VGA out connection for a monitor
Other 'video out' connections
An HDMI out connection on higher definition DVRs
Audio in and out connections if required
Remotely viewable on Internet and Smartphone
Several USB ports
Dual Streaming To Record and Transmit At Different Qualities
Most of the better digital video recorders have Dual Streaming. This is where the DVR can be recording at a very high quality and transmit at a lower quality and data volume to your Smartphone or Internet browser. The ISPs and Smartphones could not cope with the amount of data some of these recorders are capable of handling.
Viewing On PCs and Macs
Most digital video recorders can only be viewed on a PC because they need an Activex (small program) to work in Internet Explorer. These are Microsoft Activexs and so will not work on an Apple Mac.
Change Settings Using Your PC
You can remotely alter the settings in a DVR and view recorded files with a PC and Internet Explorer. You can view the cameras on Smartphones but cannot change any settings or view recorded files.
Use Features As a Security System
Most digital video recorders have features which can turn them into complete security systems. You can connect Infra red and other sensors to them and they also have 'Alarm out' connections so sirens and flashing lights, or anything else can be hooked up to them.
They all have motion detect which means if activity is detected the DVR will take whatever action it has been programmed to do.
All digital video recorders have inbuilt calendars and clocks so recording, alarming and other features can be set up to occur when you need them.
When an alarm situation occurs they will E-mail up to 3 addresses.
Digital Video Recorders with 3G.
Some DVRs have a 3G phone module which means they can connect directly to the internet without going through a wired broadband connection. Unfortunately these are only available at present on 16 channel models or mobile (for car truck) DVRs. Hopefully by the end of 2013, 4 and 8 channel models will also have them.
Thinking about HDD Storage
DRVs have the same type of hard drive(s) (HDD) as a computer to record CCTV video for future playback and reference.
High quality video recording takes a lot of hard drive space, so it is important to think about how long you need to hold recorded data and consider some of the factors affecting storage capacity.
Domestic and Business Requirements Are Different
In a domestic situation, you tend to know quite quickly if you have had a security problem, possibly within 1 day, so you could do with quite a small hard drive.
A business may not realise for several weeks a stock item has gone missing so would need a larger hard drive.
Video Compression, Recording Quality, Camera Numbers and Picture Size All Affect Storage Capacity
A major influence on the amount of storage needed is the video compression type the recorder uses. Video compression is exactly that. The video data is compressed to as small a file as possible.
Any DVR you buy now should be H264 compression. Older types were JPEG compression and MPEG compression, which used up to 5 times the storage of H264.
The video compression also affects how fast and how much video data you will remotely receive through your Smartphone or internet browser. H264 is the best format at present.
Another factor affecting the storage needed is the quality of the video being recorded. All DVRs ask in their setup 'how good do you want to record, POOR, GOOD, VERY GOOD, EXCELLENT' or similar.
Also affecting storage is the number of cameras and their quality which will be connected to the DVR.
And still another factor affecting stored data is the SIZE (resolution) of the picture being recorded.
Common sizes pictures can be recorded at:
D1 (720X 576 pixels)
4CIF (704 X 576 pixels)
CIF (352 X 288 pixels)
QCIF (176 X144 pixels)
The more pixels the better the picture.
Most 4 channel DVRs are D1. Eight channel have some or all channels D1 and until recently most 16 channel digital video recorders were CIF. Now the trend is to have all channels D1 - with the corresponding stack of hard drives to cope with the data storage requirements.
If someone tells you a small hard drive will last 3 months you should ask "at what recording quality and resolution?"
With an all channel D1 recording DVR and high quality cameras you have the best possible quality...and it is very good quality...before going to the next step which is High Definition.
We have DVR DIY kits that come complete with everything you need to install a powerful security system.
We can install your system for you if you prefer.
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