In the design of security systems, and in particular of video surveillance systems, it is necessary to correctly size the resources for the transport, processing and storage of data. This need derives from the management of multimedia streams, which, despite the compression algorithms available on the market, have a significant “weight” by nature.
Although each plant has its own specific needs for network infrastructures and storing systems, it is possible to indicate some rules that are generally valid:
- if the available data transport network has a limited or unstable band, it is always suggested to provide a recording directly on the camera or via a local registration node. In such cases, the recording flow should be of the best quality possible (main-stream) and it is also suggested to provide a lower quality flow (resolution, FPS) for live viewing in the Operating Room (sub-stream)
- if the registration happens only in the Operating Room, the video flow must also be of the mainstream type
- when it is compatible with privacy and there is the possibility to protect the recordings from any illegitimate export it is always suggested to adopt recording systems, even if this happens locally on SD
- the use of event recording (e.g. on motion detection) is suggested only if there is the possibility of recording also the previous events, in order to have sufficient evidentiary material
However, even considering these guidelines, the sizing of hardware resources for information processing and storage systems can be complex.
In particular, the complexity is given by the characteristics of the scene shot; indeed, the compression algorithms are more effective when the scene variations are minimized. For example, a camera that monitors a parking lot will develop a smaller size of data (transport and storage) than a camera that monitors the inside of a railway station.
Elements such as the contemporaneity in the number of flows, their quality and the FPS should also be considered in assessing the band of the transport network.
Moreover, in order not to have situations of insufficient resources, sizing must always be based on the maximum peak of system use and processing load.
Prassel is available for its Partners to support the Design of Security & Safety systems that use the ViMS software suite.