Cyberwatch Security Communication Systems, Inc.

Video Recodring Systems


Network Video Recoding (NVR): Network Video Recording Systems or "NVR" are software based recording systems that run on servers or embedded appliances. This system software receives the multiple streams of the network videos from different video imaging systems, either IP camera or video encoder/server systems and stores the video frames on a local hard diver or a storage attached network systems.

Generally the NVR systems remain in the same subnet where the Imaging systems are located. In some applications, however, complex networking topologies require that the NVR and Imaging systems exist on different networks. In this condition,  great care in the design of the CCTV network is required in order to provide proper quality of service and delivery of the video to the terminating points (PCs and PDAs) where the video will be decoded and displayed.

 The NVR systems generally have the video decoding modules where the streaming video is decoded and displayed to the end user. The current trend in the digital CCTV industry has been towards open system architectures. In this setup, the NVR systems are designed with a variety of decoder modules and have compatibility with different video compression profiles as well as various camera manufacturers.

The diagram above shows a typical deployment of a NVR system with IP based imaging systems. An Ethernet backbone, which is basically a Local Area Network (LAN), is established with a combination of Layer-3 and Layer-2 switches. IP address assignments and possible local URLs are assigned to the IP imaging devices, local monitoring station and termination services.

 NVR receives the control messages for authentication of the user and devices on the network and grants access to view the camera, or issues PTZ (Pan/Tilt/Zoom) commands to the cameras. The NVR also needs to be able to push the IP video to particular terminating points and monitoring stations at the request of properly authorized operators. The connection from the NVR to camera for recording and view of the video streams at the NVR console can be assigned to the specific IP address ports designated by the camera manufacturers. The remote view of the video streams and the function of sending control commands to the PTZ can be on the IP address port-80 and can be handled using HTTP transports.

A Router/VPN/Gateway should be integrated to this CCTV network in order to provide remotes access capabilities to the CCTV over the Internet and Wide Area Networks (WANs). The remote access can be established via Secure Socket Layer (SSL) appliance which provides a secured connection over the IP address port-80 and is suitable for remote client access via web browsers.


Digital Video Recording (DVR) :

Digital Video Recording systems are appliances which can take multiple Composite Video (CV) signals in NTSC or PAL formats. The DVR system then converts and compresses the video to digital format, and archives it to a local or network storage system. The DVR systems have bundled NIC (Network Interface Card) and TCP/IP networking stack capabilities where the video can be accessed remotely over the IP networks either in a browser interface or by client in a view station at termination of the video streams.

DVR systems are the entry points for storage capacity of any Digital CCTV installations. There are also hybrid solutions available where the functionality of the DVR and NVR systems are combined. In these platforms the appliance has input ports for the CV video in addition to the Network Interface that can accept video streams from the IP imaging systems. These installations are appropriate where the legacy system is leveraged with new IP system installation.

In selection of Hybrid DVR/NVR system, a great deal of care and diligence must be exercised to make sure the appliance has adequate CPU utilization available for managing the DVR archives and processing the IP streams. This is especially critical when the appliance is supporting multiple compression profiles and may need to decode these streams for display on the console as well.


Please contact Cyberwatch regarding your design and applications, and the best solutions provided in the Digital CCTV industry.


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