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JVSG, the Joint Video Surveillance Group, have developed a great software tool which helps you to calculate the bandwidth needed for network CCTV cameras.

This is one of the major concerns expressed (typically by IT Managers) when people suggest adding video cameras to their network.

The software can calculate the bandwidth requirements for cameras with all the common resolution specifications and allows you to calculate the effects of varying resolution, frame rates, numbers of cameras, the video compression standard (H.264, MPEG4, MJPEG) etc.

You can even estimate the impact of varying amounts of motion activity in the scene.

See below for more information on the settable parameters, or click the image above to visit their website.

You can download and run a FREE 45-day evaluation copy of this software from their website, and if you decide to buy it’s just £39 to licence the software for continued use.

• Resolution – Camera resolution in pixels. You can select resolution from the drop-down list. The list contains most popular PAL and NTSC camera resolutions (like 352×288 CIF PAL, 704×576 4 CIF PAL) as well as some typical network cameras resolutions (like 640×480) including megapixel resolutions (1280×1024, 1600×1200), HD and full HD resolutions (1920×1080) as well as others.
• Compression – Video compression. You can choose from MPEG4, H.264, four levels of Motion JPEG (MJPG) compression (from Low to High) and “RAW Data”. If you use Motion JPEG you can use different JPEG compression levels. If you use low MJPEG compression (level 10) you get best quality of picture and about 10 times lower frame size. If you use Medium MJPEG compression (level 20) you usually obtain a good picture quality and an optimal Quality/Frame Size ratio. With a JPEG level of more than 50 your picture becomes bad for video surveillance purpose.
• FPS – Frames Per Second. Typical FPS for video surveillance system is from 5 to 15 frames per second. In some applications (like CCTV in casino) it is required to use higher speed values (25-60 FPS). Alternative name for FPS is IPS (Images Per Second).
• Days – Required length of video archive in days (24 hours). Used for storage space calculation.
• Cameras – Number of cameras in your CCTV installation with the same parameters.
• Recording % – Estimated motion recording activity. 100% for constant recording. This parameter is used to calculate disk storage space in case the video is recorded on a schedule or on a motion detector.
• Image Complexity – Frames from some CCTV cameras are more detailed and have a higher frame size.
• Motion % – Motion activity (100% for constant activity). This parameter is used for MPEG4 and H.264 bandwidth estimation.

Lux levels are quoted by all IP camera manufacturers to indicate the low light level capabilities of their cameras.

The problem is that the lux scale means nothing to most of us, and we are often asked to give an indication of just what is meant by 1.0 lux or 0.01 lux.

Somehow, us saying “quite dark” or “very dark” never seemed very satisfactory!

We checked with Wikipedia:

The lux (symbol: lx) is the SI unit of illuminance and luminous emittance. It is used in photometry as a measure of the apparent intensity of light hitting or passing through a surface. It is analogous to the radiometric unit watts per square meter, but with the power at each wavelength weighted according to the luminosity function, a standardized model of human brightness perception. In English, “lux” is used in both singular and plural.

That’s that cleared up then! 😉

We don’t really think that the information on the Wikipedia page is quite what our CCTV camera enquirers are looking for, so we’ve created our own lookup lux chart with indicative pictograms to give you a visual representation of relative lux light levels.

Click the link to view the chart as a pdf – Lux Light Level Chart.

We hope that’s helpful?

You might also be interested in our article on IRE and Lux Levels.

If there’s any other CCTV terminology that we can de-mystify for you then please feel free to get in touch and let us know. You can use the comments below or visit our IP CCTV Forum.