There is a dilemma with advances in technology. It is the cost of incorporating the new technology when earlier technology still seems to work. In the field of CCTV advances in digital recording and storage systems is forcing many to face the expense of replacing analog recording and storage. Where Video Cassette Recorders were once the rule, they are now being phased out by Digital Video Recorders as prices continue to fall and storage capacity continues to rise. That is not to say that VCRs do not still have a place in the surveillance industry, just that there are fewer places that DVRs are not the better option. Because VCRs are so inexpensive today and so many people are comfortable with their use, they can still be a viable option for some end users. It's difficult to imagine though, large, complex CCTV installations that would today incorporate an analog-based VCR surveillance system with its complex system of tape storage and retrieval. However, in instances of a single camera and budget restraints, the VCR is still a viable option. Analog videotape is fragile, can wear very easily and deterioration occurs with each recording or with each generation of copying. It is also slow to retrieve an event on tape even with time and date or alarm search modes. These are not issues with digital recording. Video Cassettes big advantage remains to be the prevalence of VHS machines in police stations and court rooms. The proliferation of different digital units makes it difficult for the authorities to support them all but as advances are made this issue will be addressed as well. The two most common reasons for choosing digital over video recorders are quality of the recordings and the ease of search and retrieval of events.

An industrial VCR can be set to record with small intervals between images to compress 24 hours of recording on a three-hour tape, as opposed to the continuous recording of a domestic unit. This however creates a strobe light effect when playing it back which may not be acceptable in some situations. Many end users are content with a 24-hour recording capability although some VCRs are feature-rich enough to provide 168 hour and 960 hour recordings. Customers that require recording over weekends and similarly extended periods value these options.

The greatest weakness of the VCR is poor tape management. A stock of high quality tapes must be stored and handled correctly as well as replaced daily. Such shortcomings are not the fault of the storage system itself but rather the operation. Over using a tape is in itself results in poor recordings which are not such an issue with digital recorders. Maintaining a VCR based system can be time consuming compared to that of a digital based system.

A DVR records images onto an internal hard disk, ensuring high quality, clean, undistorted reproduction. Ease of search and retrieval of an event as related to time and date or alarm. Some products allow search for motion in a camera while still recording.

DVRs are either PC based units running either Linux or Windows or Black Box units that use proprietary operating systems and have a conventional CCTV interface to the user.

As the hard disk capacity of DVR systems continues to rise, the initial high cost of a hard disk compared with a VCR tape is no longer a major issue to end user adoption of Digital Video Recorders. Users with very large storage requirements, such as banks and other financial institutions, can incorporate groups of hard drives to provide the ideal solution, capable of archiving months of easy-to-search footage or one month of higher rate recording.

The industry is obviously moving forward with digital recording and its many advantages over analog tape; i.e.: their ease of use, search functionality, network compatibility, picture quality, the security of the image and the opportunity to break free of the limit of recording a maximum of 25 frames per second. Digital recording is the ideal solution in diverse situations such as retail, banking commercial offices and industrial facilities. To date it is unsurpassed in providing evidential image quality required by police forces worldwide and the ease with which archived images may be retrieved has made DVR immediately popular with the security industry and end user. It is the obvious choice for any new prestigious installation, but also offers the perfect upgrade route for one using a VCR with or without a multiplexer. And now with “Pre-Event� recording available, (the capture of lead-in views to an event), something unavailable on VCRs, there is yet one more reason to make the advance.

Partly due to the high processing power required to handle large volumes of CCTV images, the security industry is one of the last industrial sectors to latch onto PCs. High processing power has only recently become available on an affordable PC. However, since PCs are so common place many end users are having little difficulty in making the transition. Embedded software in DVR units is sufficiently sophisticated for an operator with limited PC knowledge to grasp it with ease. Simple operational controls and familiar looking drop down menus ease the learning curve as well.

A DVR really comes into its own when a rapid recall of archive image is required. Instead of investing hours retrieving an image capture, archived footage can be searched and an image retrieved in a matter of seconds. Other features unavailable on VCR are fast forward and reverse play, giving even further functionality.

The single most important advantage however, is network compatibility, which gives users the option of remote monitoring, control and access to archived images. Every communications network that supports the IP protocol is accommodated including Ethernet (LAN and WAN). Care must be taken however, to be certain that control of images accessible across a network are secured and protected from tampering. This is possible by using digital watermarking compression technology. A far cry from the physical security required to protect VHS tapes.

As with approaching any new technology for the first time, there is new terminology to understand. Training is therefore necessary, and many companies such as 2Mcctv, offer suitable courses to equip installers with the technical and product knowledge they need.

As with approaching analog systems, consider first the requirements of the installation. What am I as the end user wishing to accomplish. Is storage necessary? What would be the purpose of storing images (security, staff management)? What volume of images needs to be recorded and archived from how many cameras? Can the staff be relied upon to manage either an analog system or digital system? And, do the images need to be archived off site or accessed from elsewhere?

Whereas analog is ideal for small, single site, cost conscious installations where deterrence is the primary requirement and staff can be relied upon to keep up with tape management, digital is the preferred solution wherever the recording of high quality images is essential. Connectivity to a network, integration to other systems such as ATMs, and size and complexity of the installation are also determining factors as well as high recording capacity.

In reality, the storage device is only one aspect of a much larger installation. Storage options must consider the whole system and all its complexities before a decision should be made.