For the last couple weeks, we have been suggesting solutions to a few common issues that the administrator of a network based VMS system will face. These issues are divided into 2 elements: hardware/software and the human element. Today we will discuss the impact of adding video cameras to your system and what that does to your existing bandwidth and storage.
The person or department within a company that is responsible for managing the growth and stability of a VMS must take into consideration the changing requirements for bandwidth and storage as cameras are added. Security systems are increasingly taxed with supporting higher and higher megapixel cameras, and the demand that those cameras put on a system’s network and storage capacity can increases exponentially.
Additional bandwidth is necessary to transmit high resolution video as well as to store that data for the specific timeframe required by the company. An example of what is expected is highlighted in one of our recent projects in Fort Myers, Florida: Each of the popular 180 degree megapixel camera used in this project actually contains three 4K cameras, pointing in different directions. Just one 4k camera equals 9 megapixels , which in turn equals an amazing amount of data being pushed through a network. This makes both bandwidth and storage a significant challenges for the engineers of the Fort Myers installation.
Several things can be done immediately to mitigate the huge amount of bandwidth and storage required. For example, a camera can be set to record video at a lower frame rate. While 30FPS was long the gold standard in the days of standard definition video, user’s of today’s megapixel cameras are most often willing to accept a lower recording frame rate, such as 7FPS. While the video may be a bit choppy, the higher level of detail captured in each frame makes it this compromise well worthwhile.
Another solution is to take advantage of motion activated recording, whereby cameras record at a very low frame rate until a motion sensor triggers them to record at a higher FPS.
In terms of calculating bandwidth and storage needs, there are other factors that also affect demand. Cameras that are positioned in locations with a lot of activity will generate higher data transmission rates and larger recorded file sizes than those in areas of low activity, even if they are set to record at the same FPS and resolution. But, how does that administrator determine all the parameters necessary to accurately and cost effectively make those buying decisions?
Very simply – use the Sentry VMS System Configuration Estimator created by IPVideo Corporation. The number of cameras can be entered for several different types of cameras to develop a complete system design. Default parameters are automatically provided for FPS (frames per second), Recording Hours and Motion Percentage (if motion detection is used). These values may be adjusted by the user to match the system being considered. The Image Size values for H.264 compression are averages for streams with moderate to light motion. If the user expects heavy motion, these sizes may be increased by 50%. Click “Update” to recalculate your design, “Reset” to return ALL values to defaults, or “Print” to create a hard copy of your design. Printing your results to a PDF is a convenient way to document them.