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Digital video recording is rapidly coming of age though the current diversity of technologies does put specifiers and installers in something of a quandary as to the relative benefits and disadvantages of each system, and which one – if any – will eventually prevail. Thus far the choice is between fixed hard disc systems, tape (DVC and D-VHS) and recordable DVD (digital video/versatile disc).


Historically fixed disc systems were the first to appear, from the mid 1990s onwards, capitalising on the huge increases in speed and capacity of PC type hard disc drives and on-going developments in digital video processing and compression systems. The downside of hard-disc recording is the need for separate backup or archiving facilities as data on the hard disc is normally overwritten when the disc is full. Tape based systems have the advantage of using a relatively familiar recording media – i.e. removable tape cassettes – which are comparatively cheap and flexible and can be easily archived, and this is likely to be a key selling point for recordable DVD, though it’s still very early days with this particular format.


The DPS Watson is a state of the art hard disc digital video recorder from Canadian based Digital Processing Systems Inc., (the DPS Security Division was recently acquired by GYYR). Watson, presumably named after Sherlock Holmes’ erstwhile companion, is a single channel real-time/time-lapse machine that can effectively replace an analogue tape machine in most applications and installations. The headline features are recording times of up to 960 hours in time-lapse mode, using the standard 28Gb hard disc drive. It supports up to 7 SCSI-2 drives (2 internal, the rest external). Recording speeds can be adjusted from 1 field every 20 seconds (0.05 field/sec) to real time PAL at 50 fields/sec, audio recording is possible at all speeds. Resolution is 720 x 486 per frame which is equivalent to well over 500-lines.


Replay speed is variable using a front-panel mounted jog/shuttle dial. It has one alarm input and a video loss alarm, plus a motion detection system with editable detection grid. System status and alarm events are automatically logged and it has a calendar function for setting recording times on a daily or weekly basis. Watson is compatible with most multiplexers and a text insertion facility allows it to record ASCII data from devices like cash registers and ATMs. Date and time information can be burned into the recording and advanced search facilities can locate sequences by time/date, event or text entry.


The operating system uses a sophisticated password protected graphical on-screen display system – with context sensitive on-line Help -- recorded data is electronically watermarked to prevent tampering. Watson can be remotely controlled and images monitored using a suitable multimedia PC and optional software (minimum spec 166 MMX Pentium with 32Mb RAM). Handy extras include the possibility of a network or remote dial-up connection to update the software using its PC card slot. It supports a wide range of storage devices, including Jaz and Zip drives; our review sample was fitted with a Panasonic DVD-RAM drive. 


From the outside it looks fairly similar to a time-lapse VCR. On the back panel there’s the PCMCIA (PC-Card) slot, D-Sub connectors for a hard-wired keypad remote, a serial port for text insertion data, a SCSI port for external drives and a row of video and audio input and output sockets. The video options are composite (BNC) and S-Video (mini DIN), audio connections are handled by a pair of phono/RCA sockets. Alarm connections are via a plug-in terminal block.


On the left side of the front panel there’s a drop down flap covering the two 5.25 inch drive bays. In the middle there’s a row of buttons for function selection and password entry. To the right of that there’s a four way cursor control for the on-screen display and on the far side is the aforementioned jog/shuttle dial. Inside there’s one large and densely populated PCB and a PC type enclosed power supply module with built-in cooling fan. The disc drives are stacked on the left hand side.


After boot up the machine defaults to recording mode; to change mode or access the on-screen display it is first necessary to input a user name/number and four-digit PIN. Recording stops in all cases, which is a disadvantage if, for example you simply want to monitor disc usage. Menu displays are easy to navigate using the cursor buttons, but rather restrictive as it is not possible to quickly exit or move between other functions without having to re-enter the user number/name and PIN every time, and this can become quite tedious.


There are two setup options, ‘Quick’ and ‘Normal’. The Quick setup screen covers audio on/off, what happens when the disc is full (stop or overwrite), recording mode (2-hour real time to 960 hours time-lapse in 24 steps), disc-full action (bleep on/off), clock setup, multiplexer input setup and disc format. The Normal menu goes into much more detail, with sub menus for the clock, calendar timer, events log, disc management, installation, reports log and password change. The Install menu covers the most ground with more sub menus for setting event and pre-event recording, video input (including camera ID/title setup), text insertion, multiplexer setup, time-lapse settings, alarm configuration and motion detector setup.


Routine playback operations are fairly straightforward. After entering the play mode there’s a choice of  ‘Play’ or ‘Time-Lapse’. Play mode displays a list of recorded clips, selection is made using the cursor button or the jog dial, playback is initially at normal speed but speed and direction can be varied using the jog/shuttle. During replay an inset box shows replay mode and speed, clip time and date and a button to archive the clip. The status display can be moved to any of the four corners of the screen during replay in case it obscures important picture detail. There is a facility to add a date/time display to the image, it can be re-positioned to other areas of the screen and move it incrementally. Unfortunately this feature, like several others, is buried deep in the installation menu; backtracking out of a set of sub menus to check the results of a change can be hard work and the constant need to input user IDs adds to the time taken to get the system up and running.



The obvious question has to be, how does digital picture performance compare with tape? It all depends on the compression setting, quality is unaffected by recording mode and real-time recordings look identical to 960-hour time lapse at the same compression settings. At the highest compression level of 35:1, which gives the greatest disc capacity, it’s worse than whiskery old VHS, and that’s on a bad day with a worn tape. The image is very soft and heavily defaced by processing artefacts. A mid-range setting of 20:1 is well into the VHS to S-VHS ballpark, but with noticeable lower noise levels. On the lowest setting of 10:1 image quality is excellent, comparable with tape-based digital recording media, the picture is crisp with very little noise, colours are accurate but a bit flat, lacking the vibrancy of the best analogue recording systems, which are usually much better at resolving shades and subtle graduations.


However, what really sets Watson apart from just about every other type of video recording system -- tape and optical disc -- is the ability to instantly change speed and direction during replay, with no picture break up. It is most impressive being able to jog backwards and forwards through a sequence, with no delay and no disruption to the picture.


The audio recording facility is a welcome bonus but it has to be said that the quality is poor. The bandwidth is quite narrow but it’s fine for speech and incidental sounds. However, the really good news is that it works at all recording speeds, including 960 hour time-lapse, which is something no analogue VCR is capable of.



There’s much to like about Watson but it does have a couple of rough edges. The biggest one is the operating system, which is visually attractive and superficially easy to navigate, but ultimately clumsily implemented. It’s basically very annoying; it’s no great hardship during installation -- which should be a one-off operation -- but it spills over into routine operations and getting the unit to do simple things, like playback a recording is not as intuitive as it should be. Functionally Watson doesn’t add significantly to what’s already available from top-of the line analogue time-lapse VCRs but video performance is potentially excellent and whilst audio quality isn’t much to write home about it is a very welcome extra. Watson moves digital recording technology another step closer to the mainstream market and is yet another nail in the VHS coffin.



Video inputs               1 (composite & S-Video)

Video outputs             1 (composite & S-Video)

Audio in/out                mono line level        

Resolution                  720 x 576 pixels (>500 lines)

Recording rate     1 field/20 secs  – 50 fields/sec

Compression              10:1 to 34:1 variable

Disc capacity              28Gb standard, expandable (max 7 SCSI-2 drives)

Archive media            various (test sample DVD-RAM)


Power supply              230 VAC 50Hz

Weight                        7.7 kg

Dimensions                 431 x 406 x 122 mm





Product design             9

Build quality                           8

Ruggedness                            8



General functions                     8

CCTV functions                     7         

Ease of use                             7

Instructions                            7

Manuf. support                        ?         

Performance                           9

Video quality                          9



Ó R. Maybury 2000 0604



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