Selecting the right DVR

Number of Channels

When selecting a DVR the main consideration is the number of inputs (cameras) that can be connected and recorded. DVR either come in 4 Channel, 8 Channel or 16 Channel. Most also come with the ability to record audio from a microphone as well.

Recording Quality

Quality is also important because if your recorded video is not clearly captured it is useless when trying to identify identifying characteristics such as people’s faces. Record quality is made up of two components the resolution and the frame rate.

Resolution is how many pixels (px) of video is recorded – the more pixels the better the detail the video recorded has. There are 6 main categories of resolution. See the table below for details.

Name

Pixels (height x width)

D1

704 x 476

4CIF

704 x 576

2CIF

704 x 288

DCIF

528 x 384

CIF

352 x 288

QCIF

176 x 144

 Frame Rate is how many frames per second are recorded. The human eye can see 25 fps (Frames Per Second). If the video is recorded at 25 fps then it will play smoothly just like you are watching TV. If you lower the frame rate then the video becomes less smooth and similarly to the movements that a robot would make.

Number of days captured – HDD Size

Just like a DVD or a VHS video tape there is a certain amount of video that can be recorded before you run out. Most DVRs have a recycle mode so that when it runs out of space it deletes the oldest recording and writes the new video there. The bigger the hard disk drive (HDD) that the DVR has the more space it has and there for the more days you will get recorded. The minimum number of days that we recommend to be recorded is seven (one week)

Other DVR  features

Depending on your individual requirements you should also consider the following features when purchasing your DVR.

Network – Can you view live or recorded video from the DVR from within your LAN (local area network) or via the Internet?

Mobile Devices – Can you view the live or recorded video from your mobile device such as an iPhone or Windows Mobile Device?