The CCTV Blog

There are a lot of variables that affect what you see on the monitor when viewing video playback files from a CCTV security camera system. Frames per second (FPS) are usually one of the first and main considerations when making a system purchase, but there are a few things you should know before running out and buying a surveillance system that simply boasts “30FPS!”.

Frame rate is defined by how many still images per second are being displayed, and affects how smooth a video appears. If you have a low frame rate of say 7 FPS, you are going to see images that appear to jerk through motion. In some cases, this slightly jerky video is acceptable, but, if you are going for maximum clarity and detail, it may not be. As the FPS increases, so does the smoothness of the video. The maximum FPS you are going to see in the surveillance industry is 30 FPS, which is about the same number that the human eye can register. Most people will not be able to tell the difference in 30 and 15 FPS, though, because they both produce relatively smooth video. Check out our FPS Comparison Video for a side-by-side comparison of 3, 8, 15 and 30 frames per second.

On most digital video recorder (DVR) systems, whenever you pump up one setting, you are going to lose something in another area. DVRs that advertise 30 FPS per channel are basing that figure on a set image size. For instance, if you get a GeoVision GV800 card that has 30 FPS per channel, that number is based on an image size of 320×240 pixels. On that Geo card, if you increase the recording resolution from 320×240 pixels to 640×480 pixels, your FPS per channel will drop by about half. You would then be viewing recorded video at about 15 FPS. If you increase the resolution again, to 720×480 pixels, the FPS will drop again by about half, leaving you with about 7 FPS, which may be undesirable.

Some of the newer, high end DVR cards are now using hardware to compensate for the loss of frame rate when increasing image size. These are not, however, inexpensive systems. The GeoVision GV-1480A capture card, for example, will allow you to increase the image size to 720×480 and lose only 1 or 2 FPS.

The technology is continuing to advance, and hopefully we will see more affordable, real time recording solutions in the near future. Until then, you have to look at your application, determine what level of detail and clarity you need, and go from there. Remember to always check the maximum FPS per channel and at what resolution that records at. It may be hard to make out subjects at 320×240 or 640×480 pixels, especially at 7 FPS, so if you want a truly effective security camera system, you probably want to up your expectations on pricing, etc, and go ahead and spend the extra money to be truly protected.

If you have had experiences where buying higher quality equipment has saved you in the long run, or visa-versa, please let us! Real world applications provide the true value that allows people to make educated decisions about future projects and purchases, and we really appreciate them.