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Most revolutions only become apparent long after the event but it’s fairly obvious that the security industry is in the midst of a quite extraordinary one right now, arguably the biggest and most important period of change since the development of the surveillance video camera more than fifty years ago. The technology in question is digital video recording, which is poised to supersede analogue tape as the recording medium of choice for video footage. It hasn’t happened yet though, nor are all analogue video tape recorders about to be rendered obsolete, but it is becoming abundantly clear that VHS, which has been around in one form or another for almost a quarter of a century, is approaching the end of its life cycle.


Unfortunately, for installers specifiers and indeed everyone in the surveillance business the future isn’t as clear-cut as we’d all like it to be and there are several pretenders to the VHS throne. The first indications that analogue tape’s days were numbered came in the early 1990’s with the arrival of the first fixed hard disc recording systems, more recently several tape-based digital formats have emerged including DVC from Sony and D-VHS developed by JVC, and there are a number of recordable disc systems in contention, such as DVD and Video MiniDisc. However, hard disc systems have continued to be refined, helped along by major advances in digital video processing techniques and massive reductions in the cost of high-capacity PC type disc drives.


The only significant drawback to recording digital video on a hard disc is that unlike tape cassettes or recordable magneto-optical discs, it is not a removable medium and doesn’t lend itself easily to archiving. Data on the disc has to be continually overwritten so in order to store or backup recordings they have to be transferred to another storage medium.  Nevertheless, it’s not an insoluble problem, which brings us neatly to the GYYR DVMS 400 ‘Digital Detective’. It’s one of a family of products that GYYR has added to its range following the acquisition late last year of Canadian based Digital Processing Systems Inc.


The DVMS-400 is a ‘one-box’ solution for small to medium scale installations, it comprises a digital video recorder with built-in 4-channel multiplexer/quad and motion detection facilities with a text input – for connection to ATMs tills etc – on each channel. The video recorder section operates from 50 fields/sec real time to 0.05 field/sec (1 field every 20 seconds) time lapse mode, maximum resolution is 720 x 576 per frame which is equivalent to well over 500-lines. Needless to say recording times depends on a number of factors, including the capacity of the hard disc drive or drives, the number of connected cameras, compression ratio, recording intervals and whether or not it is set to record audio as well, however, to give you an idea of what’s possible, with the system set to 100% time lapse mode and maximum compression of 35:1, 4-cameras connected and recording speed at 5 fps, the standard 18Gb drive in our review sample can record for up to 22.38 hours, before stopping, or recycling. At the slowest recording speed (0.05 fps) recording time on a 4-camera set-up leaps to 1807 hours, or a little over 10 days.


Recording capacity can be easily extended, the system supports up to 7 SCSI disc drives (2-internal). Archiving is not a problem either since recordings can be downloaded to analogue tape at pre programmed intervals and it can be used with various removable digital recording media, including Iomega Jaz and DVD-ROM, for archiving and backup. A 5.25-inch drive bay with a hinged front panel cover is built into the case for precisely that purpose.


The quad splitter generates a standard 2 x 2 display, alternatively the monitor output can be a sequenced to show a single camera with variable dwell time (0 – 60) seconds per camera. Operating mode and recording times can be programmed to occur at specific times, or on a daily or weekly basis moreover the calendar function can be configured to take into account up to ten holiday periods. Alarm options include protected pre-event recording (2 seconds to 1 hour), it has 4 external alarm inputs, for triggering a protected event recording (i.e. it will not be overwritten), or it can be activated by a motion sensor associated with each camera channel (maximum 19 x 13 activity grid with 4 zones, variable trigger size and sensitivity). Alarm events are automatically logged and recordings can be searched by text content, date and time or event. Time and date information is burnt into the recording, along with coded image authentication data, to prevent tampering.


The DVMS-400 can be remotely controlled and images monitored by a PC, or via a network, using an optional PC Card modem or network adaptor that plugs into a standard PCMCIA socket on the back of the machine. All operations are controlled using a password-protected colour graphical user interface (a fancy menu-driven on-screen display to you and me…), which also provides context sensitive on-line help (the help info is related to whatever mode or function you or the operator is currently using) and all programmed settings are stored in a non-volatile memory, in case of power loss.


Externally there’s not much to see, it is a big black box with a fairly standard array of sockets on the back panel. A bank of BNC sockets carries video inputs from the cameras, loop-throughs and the monitor output. A set of five mini DIN sockets is included for Y/C (S-Video) camera inputs and a monitor output. Audio input and output plus external VCR control signals are handled by three phono sockets and five 9-pin D-Sub connects are used for text insertion and remote RS-232 control/communications. A single high-density 50-pin socket is provided for external SCSI drives and the previously mentioned PCMCIA card slot. Alarm connections are made via a 9-pin push-fit terminal plug and socket.


The front panel is split into three sections; on the far left is the hinged cover for the optional removable media disc drive (Jaz, DVD-ROM etc), in the middle there are two rows of buttons and a four-way cursor, for mode, display and camera selection, accessing the on-screen display and entering a PIN, which is necessary for all actions (we’ll come back to that in a moment) and on the far right is a large jog/shuttle dial, for controlling replay speed and direction.



Having so many functions and configuration possibilities obviously doesn’t help and this can make installation a long drawn out process, though it’s a small price to pay for so much flexibility. However, familiarisation and a read-through of the manual is highly recommended, installing one of these for the first time has the potential to be a fraught business!


It’s clear a considerable amount of effort has been put into the look and layout of the on-screen displays, though perhaps a little more attention should have been paid to functionality and ergonomics. The need to enter a PIN code for every action seems excessive. Apparently simple functions, like playing back a recording, or switching between camera views or quad display during playback is made more difficult by the structure of the control system, which is not at all intuitive and demands that the instruction book be close at hand at all times. Not that the manual is necessarily much help, it’s awkwardly laid out and finding seemingly straightforward items of information can be a real chore. Eventually we suspect most operators will become accustomed to its strange ways but it could have been made a lot easier to use. The presentation is clear enough, with menu selections laid out as large coloured blocks, but moving around inside a menu, or navigating from one menu to another requires a great deal of patience.



Thus far you may be forgiven for wondering what, if any, advantage digital video recording has over analogue tape; the answer is immediately obvious during playback. Unlike tape, which is a ‘linear’ medium, recordings on a hard disc can be accessed almost instantaneously; moreover moving around within a recording or sequence is much easier, with no disruption to the picture or delay when changing speed or direction using the jog/shuttle dial. There’s no jitter either, images still or moving, are rock solid and colours are reasonably natural looking though subtle shades are not always rendered as well as they might, but the most obvious benefit is picture clarity. In terms of resolution, at the lowest compression setting the picture is clearly sharper than analogue recording systems, even high performance Super VHS. But the real difference is the almost complete lack of noise. Edges and fine detail look crisper and recordings have the potential to yield much more useful information, both in terms of detail, and the ease with which they can be analysed.


The only minor niggle is the previously mentioned convoluted control system. For example during playback to do something fairly routine like change from a quad view to a single screen -- to study a recording in more detail -- can involve up to 12 button presses. Allied to that is a general difficulty in moving between clips or events, which also involves a lot of too-ing and fro-ing between menus and pressing buttons. In the end we found it was actually easier to make notes and write down times, which rather makes nonsense of having such a sophisticated display and event logging system.


As we indicated earlier audio recording is possible, and what’s more in all recording modes but in order to enable the facility you have to negotiate a series of menus and screens showing legal disclaimers, you need to keep your wits about you as the menus are contrived to make you hit the ‘cancel’ button every time... Audio recording eats into the overall recording time though by only a relatively modest amount. It probably comes as no surprise to learn that the quality is not exactly hi-fi, but it is more than adequate for capturing incidental sounds and even speech, given a well-placed or sensitive enough microphone. Even so, it’s impressive to hear real-time audio during a time lapse recording, and that’s a trick not even the best analogue time-lapse VCRs can manage, though one or two can record muffle sound in 12 hour recording modes.



There’s clearly nothing wrong with the technology and digital video recording can show fuzzy old analogue VHS a very clean pair of heels when it comes to picture quality and playback flexibility. However, rather than emulating the way a tape-based VCR works or adopting the kind of conventions that we are all familiar with, the designers seem to have gone off at a tangent and developed a control system that comes across as unfriendly and difficult to use. A digital recording device doesn’t have to pretend to be a VCR, but since the basic function is the same, it shouldn’t be so wildly different either. There are plenty of good examples of how it can be done, including PC based video editing packages and a new generation of stand-alone digital recording devices, which succeed in making what is after all a fairly complicated concept, appear accessible and unthreatening. The DVMS-400 is an impressive piece of kit and it establishes a number of benchmarks for what will undoubtedly follow but during this early stage of the technology’s development it seems like a good idea for designers and manufacturers to remember that not all end-users, operators and customers are qualified space shuttle pilots…



Design and design features                      ****

Circuitry and components                ****

Ease of installation and wiring            ****

Range and variety of functions            ****

Accompanying instructions              ***                            

Technical advice and backup            ??    

Value for money                         ??                           



ă R. Maybury 2000 0505




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