IP megapixel, HD-SDI, and 960H solutions are gaining more traction as the pursuit of HD presses on. However, both manufacturers and installers, who relied on network products, have great hesitations in adopting HD-SDI and 960H cameras.
IP megapixel, HD-SDI, and 960H solutions are gaining more traction as the pursuit of HD presses on. However, both manufacturers and installers, who relied on network products, have great hesitations in adopting HD-SDI and 960H cameras. Hybrid approaches to answer integration questions will be explained below.
Integration of IP, HD-SDI, and Analog systems
When HD-SDI solutions were first introduced in the security industry, people were discussing the pros and cons of HD-SDI and IP applications. The fact is these solutions were designed to enhance image resolutions. With the same built purpose, those products should be able to coexist in the infrastructure.
If it is an environment with coax cabling, there are a couple ways to install IP megapixel, HD-SDI, and analog cameras together. For example, by adding in Security Link Over Coax (SLOC) transmitters and receivers at the back side of network cameras, a hybrid approach is created, enabling cost-effective migration while combining the best features of analog and digital video. Since SLOC units (at the Transmit and Receive end-points) support both CVBS and IP at both ends, they are able to deliver TCP/IP digital signal over coax. This approach not only solves the cabling issues of IP cameras, but also eliminates significant modification for existing analog systems. With existing coaxial cables, received SDI signals can be sent to HD-SDI DVRs or video matrix switchers directly, allowing IP and SDI systems co-exist.
If the existing infrastructure is based on TCP/IP network architecture, where network cameras are the main focus, non-IP cameras such as HD-SDI and 960H cameras would need a transmission and conversion approach. There are two ways to convert HD-SDI signals into those signals that can be used by TCP/IP networks. One way is to adopt HD-SDI DVRs to collect the digital signals from all of the HD-SDI cameras and to generate TCP/IP signals for network routing. Then, users can manage the video data of HD-SDI cameras or perform fast remote manipulation of PTZ controlling with central management software (CMS) or the graphic user interface of these DVRs.
Another way is to use SDI digital video servers (DVS) to encode the signals from HD-SDI cameras to TCP/IP signals. Individual HD-SDI video streams then become IP signals, which support routing for network surveillance functions. Similarly, signals from 960H cameras can be collected through DVRs which generate signals for IP routing and surveillance. Taking advantage of DVS to encode video signals into TCP/IP signals in order to transport video streams over the network.
To Reach Maximum Transmission Range
One of the important transmission issues is the maximum range for coax-based analog signals vs. CAT5-based Ethernet IP communications. Some may criticize that HD-SDI signals have a major drawback; they support shorter distance than IP solutions. Fiber optic communications ease these concerns as they are widely used in large-scale security applications. Coax links can deliver HD-SDI signals in real-time over point-to-point cable up to 200 meters for standard-grade cable and up to 500 meters with a signal booster.
For the longer distance transmission of network system, it is commonplace to use fiber optic devices to transfer one or more HD-SDI or analog video streams over fiber optic transmission, which supports wavelength-division multiplexing technologies (WDM/DWDM/CWDM) to meet one-way or bidirectional transmission of multi-channel HD-SDI signals with a maximum distance from 30 to 70 kilometers.
Challenges in Shared Storage
HD images are able to be stored in embedded SDI DVRs and NVRs. However, HD-SDI has standard resolutions of 720P or 1080P at 25 or 30 fps, and the size of converted data is about 1.485Gbps. Storing such raw data requires huge costs. A more practical way is to take approaches such as network compression, D1 recording for general scenes, and HD recording for events to save storage footprints. Therefore, users can get benefits from both HD image recording and smooth latency-free real-time image sources. The numbers of DVRs and configurations of IP or HD-SDI recording can be defined based on the fact that resolutions of 720P or 1080P at 30 fps produce 400 to 650 MB of video data per hour, which means one channel of video data requires 350 to 500 GB of storage capacity per month.
Video Management
Many suppliers are introducing networked video platform to route the video data encoded by HD-SDI matrix switchers or HD-DVRs and to enhance integrated IP surveillance systems with VMS or NVRs to perform alarm triggering, information gathering and centralized administration. Such platform features strong data management capabilities to perform central management, indexing, searching, content analysis, and alarm noticing.
The front end installation can combine coax cables with fiber optics devices to transfer all captured signals to the control center, where those collected signals are routed to multiple screens and HD-SDI DVRs with networked feature for real-time monitoring or management. This system not only meets the requirements of network IP surveillance, but also enables quick and convenient configurations for different sites and resolution formats. Another aproach is to adopt video encoders to convert signals and transmit them to HD NVR/NAS/SAN for storage and management.
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