DETEXI® Network Video Management System
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— Setting up IP-Surveillance System – Hardware Considerations — Network Considerations —
Hardware Considerations
Network Considerations
Network considerations include asking the following questions. Answering these questions will help you determine how to integrate the IP Video Surveillance System with the current network —
  • What kind of bandwidth is available on the current network?
  • How many cameras will be in the system?
  • How many clients will be there viewing the camera feeds?
  • Where will the clients be in relation to the network — local to the network, or remote?

In a simple configuration with the right conditions, a few-camera system can be placed directly into the available corporate network without affecting the other priorities of the network or compromising the performance of the surveillance system. A configuration such as this typically would assume that only a few cameras are necessary, with only a few clients located inside the network. The more cameras, clients and external clients in the system, the more bandwidth required by the system.
Although it entails more planning, setup and in some cases, more hardware, the preferred configuration is to create a secondary security network to run in parallel with the corporate network.
This configuration allows the IP Video Surveillance System to do its job without pulling resources from the corporate network and vice versa.
This also allows for more strict security policies to be implemented on the security network if desired.
— Setting up IP-Surveillance System – Hardware Considerations — Storage Considerations —
Hardware Considerations
Storage Considerations
There are several major factors to consider when determining how much storage will be necessary for the IP Video Surveillance System —
  • Number of cameras;
  • Hours per day the camera will be recording;
  • How long the data must be stored;
  • Record activity and motion level;
  • Other parameters such as frame rate, compression, image quality and complexity.
The three main variables when calculating storage use over a period of time are image resolution, compression, and frame rate. However, one must also consider the complexity of the scene to be recorded —
  • An example of a simple scene would be an IP camera recording a room with mostly white walls and not much going on, versus a complex scene with a lot of colors and details.
  • This basically means that the more complex the scene, the larger the image size.

Another consideration that will directly affect that amount of memory used is the type of recording for your system: constant recording or only when motion occurs. If recording only on motion, then the motion level or percentage of time there is motion must be considered. Once a camera’s storage use is calculated for a moment in time, it can then be multiplied by the number of cameras and the time data must be stored to determine the total storage necessary for the system. Use simulation-based storage calculator available to make these calculations easier.

— Setting up IP-Surveillance System – Hardware Considerations — Processor Considerations —
Hardware Considerations
Processor Considerations
When deciding how recording with take place (always or on motion), processor power required for the Network Video Recorder (NVR) should be part of the consideration in addition to storage requirements. Many things come into play when determining processor demand —
  • Motion sensing method (if applicable);
  • How many cameras are in the system and recording;
  • How many clients will be accessing the system at any given time.

When deciding the type of motion sensing to use, one must be aware of the tradeoffs between storage and processor demand. There are often different options for motion sensing which affect the processor in different ways. The two basic types of motion sensing are —
  • Soft motion sensing through image analysis within the NVR;
  • Hard motion sensing via physical inputs on the camera.
Soft Motion Sensing
Soft motion sensing requires less hardware because no input devices (motion sensors, light beams, door contacts, etc.) are needed. However, more demand is put on the processor in this case as the processor must constantly analyze the image frames to determine if there is motion.
Region specific soft motion sensing only analyzes specified regions of the image frames to look for motion which may cut down on processor and storage demand.
Hard Motion Sensing
Hard motion sensing will also use less storage. This option will also demand less processor work since the motion sensing is processed externally within the camera. The processor simply needs to monitor the input on the camera and store the images only when the input is triggered. The disadvantage of this option is the requirement, setup, and configuration of extra hardware.
Hard motion sensing may not be as flexible, since soft motion sensing may allow for easy configuration changes or additional features like sensitivity thresholds and regions of interest.
The Number of Cameras
The number of cameras in the system not only impacts the network that the system is on, but also the processor demanded by the NVR. Camera count per NVR server is a major consideration.
For a system with more than 50 cameras, it is often necessary to distribute the load across multiple NVR servers — NVR Domain.
This will vary with systems since the processor load per camera will depend upon the record activity and motion sensing.