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In April 1994 the video industry agreed the specification for the digital video cassette format. This month the first DVC camcorders go on sale in Japan, Rick Maybury has been looking at the first pre-production machines



It seems a long time ago now but it has been only been 18 months since fifty of the world’s leading consumer electronics manufacturers announced that they had agreed upon the specifications for the digital video cassette (DVC) format. DVC has had a remarkably short and untroubled gestation period, with hardly any controversy, or public bickering between the parties involved, which probably explains why it has taken such a relatively short time for product to move from the drawing board, into the shops.


The products in question are three DVC camcorders, from Matsushita and Sony. Matsushita, Panasonic’s parent company, were first off the block with an announcement on August 1st this year, that they planned to start marketing their machine, the NV-DJ1, on September 1st. A little over three weeks later, on August 24th to be precise, Sony unveiled two machines -- Digital Handycams DCR-VX700 and DCR-VX1000 -- that would go on sale in Japan in September, and in Europe a month later.



We’ve covered the DVC format in some detail in past issues, but it doesn’t hurt to run over the basics again, particularly now that we’ve got something tangible to talk about. DVC owes it’s existence to the fact that the VHS format is approaching to the end of its projected 25-year life cycle. Don’t worry, VCRs and tapes will be around for another ten years at least , but the progress towards digital recording and transmission systems is now unstoppable, and poor old VHS is simply not suited for the digital age. JVC, who originally developed VHS, and have more to loose than most, have come up with an upgrade that gives the format digital capability, with the recently announced D-VHS system, but this will surely only prolong the agony.


The VCR industry has seen it coming for a long time; proposals for a domestic digital video recording format were circulating ten years ago but the search for a replacement for VHS began in earnest in 1986 with several companies independently developing domestic digital VCRs. Not wishing to repeat the format wars of the early eighties discussions began in 1990 about standardisation and this culminated in ten companies forming the HD Digital VCR Conference in July 1993.


Back then the situation must have seemed fairly straightforward. VHS would slowly die off, to be replaced by the new digital system, but just over a two years ago an almighty fly started wading around the ointment, in size 12 boots! It’s DVD or the digital video disc, which at the moment consists of two competing systems, each capable of cramming a couple of movies, with multi-channels digital soundtracks, on a single 12cm disc. Discussions are now underway to avoid yet another damaging format battle, but that’s another story...


From the industry point of view DVD is a far better medium than tape for carrying pre-recorded material. Discs can be produced quickly and cheaply, they’re robust, convenient, and all systems to date have backwards compatibility with audio CD and various other optical disc formats. The technology also exists, that will allows DVD systems to record, as well as playback video, and this has raised a number of important issues, that have had a knock-on effect on the future direction of DVC.


The trouble is digital recording systems like DVC or DVD have the potential to make almost identical copies or ‘clones’ of other recordings, so no more whiskery pirate movies, and that concerns the software industry. The copyright issue is a massive headache for VCR manufacturers, who would love to go ahead and build DVC video recorders, but without agreements on copy-protection and copy prevention technologies, there can be no pre-recorded software for DVC. No software means VCRs wouldn’t have a cat in hell’s chance of selling as a replacement for VHS.  Rather than wait the industry has decided to press on with DVC camcorders, and hope the copyright issues will get sorted out sometime in the near future, unless of course recordable DVD comes along to muddy the waters even further!



So much for the history lesson, but what about the technology? Two other reasons why DVC has come to fruition so quickly is that it’s not dependant on any radical new technologies. DVC tape is 6.5 mm wide, it’s an advanced dual-layer metal evaporated (ME) formulation, similar to that used in Hi8 cassettes. There’s two types of DVC cassette, the standard size is just a little larger than an audio cassette, containing enough tape for up to four and a half hours recording time. Mini DV cassettes are meant for camcorders, mechanically they’re similar to 8mm cassettes and they have up to an hour’s worth of tape. DVC cassettes also contain small (1.5 kilobyte) microchip memory, that stores data relating to the dates and times of recordings, plus index marks for fast track access on pre-recorded tapes. A set of contacts on the backside of the cassette mates with connectors inside the deck mechanism.


DVC tape deck mechanisms are very similar in design and layout to VHS and 8mm, though obviously they’re a lot smaller. The only major difference in fact is the speed of the spinning head drum, which revolves at 9000 rpm, that’s around five times faster than VHS, and is necessary to cram in the huge amounts of digital information need for high quality video recordings, around 11 gigabytes in the case of a 1-hour Mini DV cassette, or 50 gigabytes on a standard DVC tape. The digital data is lightly compressed (5:1), and read or recorded on the tape at a rate of 25 megabits per second. As the information going on to the tape is in the form of numbers, error correction systems ensure that DVC decks are better able to cope with knocks and bumps during recording and playback.


DVC uses a digital component recording system, which basically means video information is broken down into three elements, relating to the colour and brightness of the recorded image, processed, compressed and then recorded using 8-bit quantisation techniques, not dissimilar to digital audio on a CD in fact. Frames are individually compressed (unlike MPEG compression systems, which work on the differences between frames), so no data is lost. All this adds up to a recording system that is theoretically capable of resolving 500 or more horizontal lines, which is only slightly less than professional or broadcast video equipment and close to the display capabilities of most domestic television receivers.


We mustn’t forget audio facilities. The DVC format has two audio configurations. In both cases the soundtrack is recorded digitally, using a PCM (pulse-code modulation) system. Stereo 1 uses 12-bit/32kHz quantisation for 4 ‘mid-fi’ audio channels, Stereo 2 is a 16-bit/48kHz system, for 2 very high quality audio channels.



So much for the generalities, time to look at those camcorders. We’ll begin with two Sony models, because they were the first ones we actually managed to get our hands on. They’re the DCR-VX700 and DCR-VX1000 and if all goes well they will go on sale in Europe this October. Prices have still to be confirmed but back of an envelope conversions from yen to pounds suggests the VX700 could cost somewhere in the region of £2-2,500, and the VX1000 £3000 or thereabouts. Both machines bear a passing resemblance to the VX1 (especially the VX1000), incidentally the VX1, is being discontinued, you’ll understand why once you’ve read this...


The VX700 is pitched at top-end users and enthusiasts; it has a single CCD image sensor, 10x zoom (20x digital), colour viewfinder and a range of digital effects, including still-frame recording  and scene-change/overlap.  It’s powered by a large Lithium-Ion battery, shooting weight is 1.4kg and is fitted with a standard AV output sockets (S-Video and composite).


The VX1000 is a far more serious machine, that will appeal to professionals and possibly even broadcast users. It has 3-CCD image sensors, for pin-sharp colours, improved low-light performance and lower noise levels. It also a 10x zoom with 20x digital mode, colour viewfinder, still frame record and scene-change/overlap facilities. Additional creative facilities include a switchable ND (neutral density) filter, manual exposure controls plus Stereo 1 and Stereo 2 recording. It’s fitted with a standard digital AV output interface connector or ‘jack’ which carries raw digital data, this is for making copies on digital VCRs, or interfacing with PCs.  It’s powered by the same high-capacity Lithium-ion battery, and all-up weight is around 1.6kg.


Panasonic’s NV-DJ1 is a strange-looking beast, at first glance it’s not clear which end you’re supposed to look into... That’s because they’ve given it a large lens with 3-CCD image sensors at one end, and a 0.7-inch colour viewfinder screen, with a big sportsfinder type eyepiece at the other. Like the Sony machines it has a 10x zoom, with 20 digital mode, a fairly routine assortment of manual and automatic exposure functions, plus a high-performance still or snapshot recording facility, and the standard digital AV jack connector. Price and launch date have still to be confirmed but Panasonic hope to have NTSC spec machine in Japanese shops from September 1st, and Europe (or at least Germany), by next summer. The quoted Japanese yen price translates to £1850, but don’t read too much into that.


All three machines are compatible with existing VCR formats, and have standard analogue composite video and S-Video output sockets. This means you can record from DVC to VHS or 8mm, though there will be a substantial reduction in picture quality as existing formats cannot handle the increased amount of picture information.



We’ve recently had the opportunity to try pre-production NTSC versions of all three models and the initial impressions were very favourable, especially picture quality, which in all cases was stunning with bags of detail and pin-sharp colours. Recordings are virtually indistinguishable from broadcast pictures, but we’ll refrain from saying too much, until we’ve had a chance to see pukka PAL machines.


So far so good, and not too many surprises, nasty or otherwise, but a couple of points have come to light. The least controversial one is the still recording facility on all three machines. That’s significant because unlike VHS-C and  Hi8 camcorders with the same facility, the still frame on a DVC machine is rock solid and is composed of two picture fields, not one, so the image contains twice as much detail. Video prints taken from these machines (using a suitable video printer), look almost as good as conventional still photographs.


The other, less endearing feature is the lack of standardisation when it comes to editing, one of  the format’s strongest features. DVC should have been a golden opportunity to bury the editing hatchet and come out with a common edit control protocols, but no, the Sony machines have Control L/LANC sockets, and Panasonic have fitted 5/11-pin connectors to theirs. The good news is that this means both machines can be used with existing edit control systems, and early adopters won’t have to fork out for new editing equipment as well, but in an ideal world Matsushita should have bit the bullet and gone for Control L. Of the two this system is better suited to the digital format and currently has the largest user-base of editing equipment.  


But what about the future? Well, there’s a glimmer of light at the end of the tunnel. The digital AV interface jack fitted to these machines carries digital data, which includes a time-code for each frame, so there’s the possibility of highly accurate digital editing systems. Our guess is that they’ll be PC-based as the one box can be used to control the video decks, process video and audio, and display the images.


It’s going to take a while for the new format to have an impact on the mass camcorder market but we’d guess that one of the first effects will be to kill top-end Hi8 and S-VHS-C stone dead. It will probably be at least another three years before we get sensibly-priced (i.e. sub £1000) DVC camcorders and palmcorders, though prices could fall quickly if the take up rate is higher than expected. DVC has arrived, and on the evidence so far it’s looking very good indeed. Look out for the very first hands-on test of a PAL production machines, possibly within the next couple of months.




* high picture quality, almost up to professional and broadcast standards

* excellent audio quality, comparable with CD and DAT

* 2 or 4-channel PCM audio tracks

* virtually no quality losses during dubbing or editing

* no-wear playback, negligible deterioration after repeated tape play

* high-quality still frame, comparable with photographic prints

* potential for faster, more accurate editing

* potential for PC control and image processing

* small, compact ‘smart’ cassette with on-board microchip memory

* stable, bump-resistant recording technology




* it’s expensive, the cheapest machines are likely to cost around £2500 at launch

* tapes will be dearer too, reckon on between £10 to £15 in the early days

* DVC spells the end for top-end Hi8, Sony are already deleting the VX1

* no change with edit control and time-code incompatibility

* formats have been known to fail and early adopters run risks

* homedeck VCRs still some time away

* zero pre-recorded software

* digital editing systems still a distant prospect

* it may be a while before cheaper palmcorders are developed

* DVC camcorders are likely to be in short supply, until production gets going



Ó R. Maybury 1995 2808





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