Video-over-IP is a technology with great future potential. However, it is also a great opportunity for the energetic, smooth-talking salesperson to convince customers to buy video-over-IP systems that produce images of half the quality of conventional CCTV systems at many times the price.
A harsh statement? Yes, but it is essentially true for today's market. Video-over-IP does give the salesperson something to enthuse about but the question must also be asked: Does it at this stage help the customer? There is a need to be absolutely sure that the technology will in fact do what the customer wants it to do.
It has to be considered that no two Internet Protocol systems are exactly alike and that Video-over-IP is not the keyword. Rather, the keyword remains picture quality that will lead to suspect identification and arrest and the capability to provide and store visual evidence that will stand up in court.
If the application does not demand images of high quality then undoubtedly video-over-IP technology will in some instances be a perfectly good or even the best solution available. On the other hand there will be applications where it falls far short of being the best solution. The point I am trying to make is that customers should not fall into the trap of getting caught up in the eager salesperson's hype and see just the positives without regard for the negatives.
The pros and cons
There are points for and against the video-over-IP technology. Among the major negatives are:
* Limited bandwidth takes compression to the extreme and results in poor image quality.
* The effect of latency in IP-based systems on PTZ or dome control means that fine control is almost impossible because of the delay in camera response, particularly over high focal lengths.
* Systems based on video-over-IP tend to centralise storage so that the user becomes vulnerable to a single point of failure.
The positives include the ability to use common computer technology, which is reducing in price while increasing in performance, and redundant storage systems such as RAID; a single cable can be used to deal with command, control and feedback; a future advantage could be that it will relieve the industry of the PAL standard. It should improve our ability to move away from PAL to HDTV, which is a huge opportunity; and in applications where high definition detail is not required, video-over-IP could share an existing network LAN or WAN.
There is little doubt that the Internet Protocol is likely to play a major role in CCTV security surveillance systems of the future, especially once improvements to systems have been implemented. But for the time being the use of IP to transmit video images should be exercised with great caution.
Know the limits
Organisations wanting to implement video-over-IP technology now need to bear in mind its limitations. If the user is able to achieve the required picture quality at competitive cost then there is absolutely no reason why the system should not be implemented.
IP is useful in small and relatively non-critical systems but I do not believe it is yet robust enough for critical surveillance solutions. Its use also pre-supposes that CCTV system installers have the ability to install high bandwidth networks. This requires confirmation because CCTV installers are knowledgeable about CCTV and network installers are knowledgeable about data, but right now, the conclusion has to be that neither is yet skilled enough for video-over-IP.
While IP is good for non-realtime transfer of large video files it raises serious concerns for realtime video transmission. Security is another concern as firewalls are adversely affected by multimedia traffic. They cause delays so users either turn firewall ports off or have to install and open many more new ports.
It is likely that there will be many digital advantages in the future, such as digital zooming without loss of fidelity, digital panning and tilting to reduce the cost of lenses and the direct control of cameras leading to increased system sophistication. It is also likely that higher resolution and larger image displays on LCD or OLED will become the norm instead of CRT.
There will also be room for hybrid solutions where IP technology would be advantageous in certain aspects of a total surveillance system application. Video-over-IP will be useful when the system needs to be accessed over a network for remote viewing or to allow remote service calls. For this the system would have to be on IP but not the cameras. While IP is standardised, the systems are not so it does mean that specific software will be needed to address specific cameras.
Dr Bennie Coetzer is joint managing director of Thales Advanced Engineering; he can be contacted on 011 465 4312.
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