Register
Login
This is a trade and distribution website only. We supply goods only to trade and distribution customers. Retail customers please call 0115 714 9990 for a list of our resellers.

DVR Recording Resolution explained

UNDERSTANDING DIGITAL RECORDING

In easy to understand language a Digital Video Recorder (DVR) usually grabs television from a CCTV camera working in television lines (TVL). TVL is known in the trade as an analogue signal and needs to be converted into a digital format so it can be stored on a hard drive built into unit. It is the job of the DVR to take the analogue picture convert it to digital and store it for later viewing.

A Digital recording is made up of individual tiny squares called pixels, many thousands of them are formed each second to build a continuously changing picture.

The quality of a recording is determined by a number of different factors but in the main, the most important factor is the number of pixels that are created in a single frame.

A frame in simple terms is one photograph so it follows that the number of pixels that are created in each photograph determines the quality. Therefore, the higher the number of pixels created the better the quality. The name the industry uses for all this is RESOLUTION.

DVRs on the market today are able to record at higher resolution, faster, i.e more frames every second. Typically, even entry level DVRs should now be able to record 25 frames per second for each camera. 25 frames per second (fps) is known as real time (television)
What is CIF resolution?

It is a standard recording size and is considered medium resolution. In the diagram (left) we show that each frame consists of 352 squares (pixels) formulating a row and there are 288 rows each containing the same number of squares (pixels).
What is D1 resolution?

Like the above this is also a standard recording resolution but this is known to be high resolution as it contains 724 squares (pixels) in a row and there are 576 rows each containing the same number of squares (pixels). D1 is the very best resolution that can be achieved when grabbing television from a TVL CCTV camera.
What to look for:

Ensure any DVR that you purchase today has the minimum capability of recording 25 fps at CIF resolution and 6 fps at D1 and note the higher the D1 fps recording ability, the more advanced and expensive the product.
Click here to go back to previous page