Industry View

The CCTV Project Planner

CCTV implementations face a lack of product standardization, a confusing bidding process, and a limiting market structure. Here is expert guidance on critical considerations about bandwidth, frame rate, image quality and more

By Jason Cowling

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Even though compression methods are strong, the organic nature of individual images cannot be measured and will vary. Even the most basic DVR's will feature most of the bandwidth control methods I mentioned above. So, again, be flexible in your expectations of bandwidth consumption. A good rule of hand is to budget for 20 percent more bandwidth consumption than you need. Even more important is monitoring consumption after the system goes online, and continuing to reduce your data streams by adjusting for the activity levels, light trends, and other factors influencing your individual cameras.

How Good Do My Images Need To Look?

Another way of helping with bandwidth consumption, and an area to think about prior to implementation is image quality. Image quality is primarily quantified through FPS (Frames Per Second). Even basic camera systems can control frames per second at the individual camera level. Also, FPS can be tied to alarm activities, so you can immediately record in high resolution when an alarm event is taking place. When thinking about your individual cameras, consider what you are looking to capture. If it's something intermittent, you can drastically reduce bandwidth consumption by managing FPS in relation to events. Many recorders also offer pre and post-alarm-event recording features that capture high resolution (high FPS) images both before and after the alarm event. This helps you to capture the entire occurrence, while at the same time saving bandwidth between events. Again, and as with bandwidth management, the real dialing-in of a CCTV system takes place after it's online, be sure to continue managing your system after it's online and you'll be rewarded with increased security and reduced bandwidth consumption.

How Long Do I Need To Store Captured Images?

Storage of CCTV data is something that gets overlooked. Remember that after this data is recorded it's going to quickly pile up and need to be either dumped or relocated to another storage medium. Even a one terabyte hard drive is going to fill up quickly enough with just a few cameras.

Most businesses won't need to store data for more than two weeks. If you take into consideration how many cameras you're implementing, what data you need to save, and to what extent you'll need to use it once it's archived, you can form an idea of the storage space and storage technique you need. If you only need to save your archived video for a period of 1-2 weeks and you have a relatively small amount of cameras (remember this is organic), you can likely specify a DVR that will hold all that data, and then rewrite itself after a two week period. You can also push data to a storage server, offload it onto tape if offsite storage is required, or burn it onto DVD. Make sure you strictly regiment whatever storage program you decide on; too often ROSI is lost because of failure to closely monitor, store, and protect CCTV archives. For IT professionals, CCTV data should be treated with the principles of Availability, Integrity, and Confidentiality that govern IT data security.