( DAT, DVD, DVC)
by Gerald McMullon 31st July 1996
I have not welcomed the digital revolution with open arms inspite of or because of knowing more than most the ultimate advantages that are inheritant in digital media.
Although it is not time to write off analogue recording it will soon become impossible to purchase top quality cassette recorders. Nakamichi, the acknowledged leaders, have stopped hi-fi manufacturing to concentrate upon computer peripherals. Although decks with Dolby S have dropped in price so have DAT recorders (the Sony TCD-D7 is being advertised for £400). It is hard to justify continued expense on high end cassette systems when DAT is now at the same price. Is the new micro-DAT Sony NT-2 going to replace existing DAT systems or compete with mini-disc?
Video requires the new 4.7Gb capacity CD format, DVD <http://www-eu.philips.com/pkm/laseroptics/news/dvd_top.htm>. This format will be used by the computer industry and could also be used for audio CDs. With this capacity direct to disk recording in 8 tracks could be controlled from a personal computer costing between £1500 and £2000. Raid systems, where drives are connected in parallel could increase this capacity. Blank DVD for recording on will be available within the next 3 years. DAT still has the advantage of wiping off a recording, re-cueing and resuming. CD-R will always be write once. However 1.7Gb optical cartridges are available for computer systems now, as are sound cards that accept digital input from CD and DAT players. With a good analogue to digital converter you can record about 3 hours of CD quality audio. Cartridges are about £60 each. The master created could then be transferred to CD-R at £5 for a blank.
Will the new DVD specification allow a 2" disc to store 70 minutes of audio CD and how would that hit DCC, mini-disc, DAT and mini-DAT? It will be interesting to see if Sony will release a mini-disc version of DVD.
There are advantages of being able to collect music, video, photo albums all on a 5 inch CD size disk, it is even possible to mix video, audio, photographs, text and graphics all on one disk. It is only software to get it played back!
There remains a problem with pre-recorded DVD. I wonder if audio CDs would have broken into the record market if there was a different format in the US and several incompatible formats in Europe. I fail to understand the fuss. Why shouldn't US releases be made available in Europe; just as albums are now. I often send 'home video' recordings to friends in India and China but can't to relatives and friends in the US without the expense of getting it transferred from PAL to NTSC. DVD and DVC could allow us to send (our own and commercially available) videos without concern over the TV standards.
If international standards can't be agreed I hope these formats will fail. Unfortunately, just as it became impossible to buy music on LPs we may find that all video releases will be on DVD only and tapes for 8mm, Hi8 and S-VHS will be difficult to obtaining forcing us to migrate to DVC or Digital-VHS <http://www.jvc-victor.co.jp/dvhs-e.html>. Standard VHS will become unavailable as soon as the 'high-end' of the market becomes established and the price for units dropped. And then, within 10 years, they will invent another format and force everybody to change again!
When CD came out I decided not to get into CDs until portables, in-car systems, computer programs and the inclusion of information (text and graphics) along side the audio were widely available. New 'improved' models where being produced several times per year; particularly with DACs (digital to analogue converters) and that 16 bit 4 times over sampling became 18 bits 8 times over sampling, 1 bit streams and now 20 bits. The original CD format has now several variations and I still cannot plug a normal CD-player into my computer or plug my computer CD drive directly into my hi-fi system. A CD-R (recordable CD) drive for a computer systems are available for as little as £400 (requiring a computer of some £1500-2000) but recordable CD-R for hi-fi is not affordable (what ever happened to Meridian's CD-R system?). Unfortunately all the promises of the 'CD format' written about over 10 years ago still have not been made available. By now I had expected to be able to link my computer up to a CD player and be presented with a list of tracks, artist information, writers, composer, tempo, even a music score as well as lyrics. I also expected LCD panels on CD players to display this information.
Now we have a new format DVD (digital video disc). It is likely that new DVD player will play back CD Audio and Kodak Photo CD and, maybe, the 'short lived' CD-I/CD-V formats (presumably now redundant). However CD-R (recordable) systems for these 4.7Gb CDs will not be available for another 2-3 years.
The format battles seem doomed to continue with the consumer being worse off; forever backing the wrong format.
Remember the ELCASSETTE (spelling?) where quarter inch tape was placed in a quality cartridge mechanism that recorded at a faster speed than compact cassette. Lack of pre-recorded material was claimed as a reason for it failure.
V2000 (Video 2000 from Philips <http://www.philips.com/>and Grundig <http://www.grundig.com/>) has completely disappeared, inspite of a rumour of a new limited edition from Grundig due to demand from owners of V2000 collections. At least beta format users can, currently, buy ENG (electronic news gathering) equipment and so can continue to playback their beta tapes.
Laservision, although still available as Laserdisc (with digital sound track) <http://www-eu.philips.com/sv/newtech/ld.html> was not supported with sufficient number of film releases. In Cambridge Laservision players and discs were available for rental. Even the films that were available were sold at much higher prices than Video tape versions. Lack of the ability to record on it has been claimed as the main reason for failure. You can't recorded on CDs, or LPs before them but at least we don't have different standards of records (33 and 45rpm having been available from the 50s world wide) and all audio CDs run at the same speed.
Digital recording requirements were originally meet at an affordable price by PCM (pulse code modulation) units but using different sampling rates. There was a 13 bit PCM unit for the Sony Beta format F1 video recorder. The inferior 8 bit PCM was included in the 8mm video format; last seen in the VCC6000 camcorder and EVS9000 editing deck. One Sony standard 8mm deck even had an option of recording six separate PCM tracks giving 24 hours of digital audio on one 8mm tape. This feature was dropped so as not to interfere with the sales of DAT recorders. None of these units had digital input or output sockets.
DAT uses a different tape format to 8mm video. There may be a good reason for this, but I doubt it. Not all DAT recorders/players sample at the same frequency as CD recordings so the information is not immediately transferable to CDs. Audio has less data requirements than video and both DAT and 8mm are used as backup formats for computer systems. A digital video system utilising the 8mm tape format (or DAT) would have been an obvious choice, but DVC choose yet another format. Possibly for the same reason that Sony has announced a micro-DAT recorder that uses postage stamp sized tapes - to reduce further the size of portable systems. This seems to be why Sony have marketed stereo micro-cassette systems in Japan and introduced the mini-disc and 3 inch CD player. The rival to mini-disc DCC (digital compact cassette) at least allows a machine capable of playing the compact cassettes and the new DCC to be manufactured. Mini-disc has the advantage of having mass produced pre-recorded discs like CDs, having partially manufactured and partial read/write sections (to add your own notes and preference, useful for computer programs but also with an interactive audio disc) and a fully recordable disc. The down side is that both mini-disc and DCC selectively loose audio information to reduce the data requirements with the assumption that 'some' frequencies are 'not heard' or masked by higher sound levels and can be ignored. This is similar to the argument that 16 bit CD recording was optimal. But today many professional musicians use 20-bit recording.
In computer data terms the mini-disc holds 160 megabytes (1Mb=160x1024x1024bytes), more with compression. Variations of the 3.5" floppy disk hold over 230Mb and new data cartridges store 1.3gigabytes (1Gb=1000Mb). DAT stores 4Gb and 8mm over 8Gb. Read/write optical drives now store 1.7Gb with 4.7Gb available soon. A typical 60-74minutes CD of music has about 640Mb of un-compressed data. 1.3Gb optical cartridges (650Mb each side) can store an entire audio CD on each side. Cartridges however are very expensive at £59 each, compared to a write once CD-R blank at £5-6 each.
The format wars in data storage for computers include more choices than the famous Beta/VHS/V2000 battle of the early to mid 80s. The 'weakest' standard of VHS won the video wars, but left a little room for 8mm as the camcorder format marginal winner. Where-as VHS looks likely to continue for a while 8mm, particularly Hi8 will disappear. The successor to the Sony VCC6000 the VX1 had no PCM sound track, and the Sony DCR-VX700/1000 <http://www.sel.sony.com/SEL/consumer/camcorder/digital.html> uses a different cassette format. So if your old Sony VCC5000 wears out or is damaged your replacement choices are not good:-
The digital battles will see any victor overthrown in a shorter period of time than winners of previous format battles..
Old 78s had been around for over 50 years before vinyl records took off in the mid-50s and lasted until about 1990. Getting albums on LPs since then has often proved impossible. CDs have been commonly available for little over 10 years and will be lucky to see through to the end of the decade (century/ millennium). Infact it is distinctly possible that none of the current formats will survive much beyond then. 4Gb ROM/RAM chips could be available in quantity and at the equivalent cost of pressing CDs today (£0.40).
DVC has adopted a 12 bit PCM system to allow for audio dubbing. Better than the 8 bit system used with 8mm and Hi8 top models, but not up to CD quality. Recording at 16-bit (as available on JVC GR-DV1 <http://www.jvc-victor.co.jp/welcome.html>) prevents audio dubbing on the same tape. A choice of 8bit/16bit at sampling rates of 11, 22 and 44 KHz as in computer based recording systems would have been better, with 16bit 44 KHz being of CD quality.
Two sizes of DVC has been announced in the press (up to 60 minutes for camcorders and up to 4 hours for decks). This is a similar system to that adopted by JVC in VHS and VHS -C where an adapter is required on some decks to play the VHS-C tapes. In addition to this some DVC tapes include a memory chip to store recording information. A Sony 60 minute tape costs about £20 and a 180 minutes tape costs nearly £50.
The two Sony DVC camcorders (<http://www.sel.sony.com/SEL/consumer/camcorder/digital.html>) have been universally praised in the press, but users on the Internet newsgroups complain about a host of problems with the quality of the image and lack of consistency of recording. These are first models of a new format and as everyone knows - don't buy first models. The second generation will have got most of the bugs ironed out. The JVC GR-DV1 has been praised for it's recordings, compact size and innovated design.
I have been unable to find out technical details on the digital output from these camcorders, not that there is much to digitally connect to. Sony never responded to my queries. In the same way that Sony never provided a digital output to the PCM sound tracks in camcorders such as the VCC5000 and 6000 and decks EVS1000 and EVS9000 (not even separate FM and PCM input/outputs) will we ever get direct digital I/O on a camcorder? This is needed for connection to computers. The IEEE 1394 (ISO 1394) (<http://www.jvc-victor.co.jp/ dvhsie-e.html,> <http://www.skipstone.com/info.html> or Firewire is available on the Sony DHR-1000 DV Edit Deck at £3300. This provides direct digital input and output and hence no loss in copying. The Sony DCVX700 has digital outputs, but apparently 16-bit audio recording and playback is a compromise the full benefits of the DVC format are not realised with this camcorder. The Sony 3CCD DCVX1000 and JVC GR-DV1 have better audio specification. Reports indicate that the 3CCD Panasonic NVDX1E is not as good as the JVC GR-DV1, although the picture quality is slightly better.
The current video capture cards available for personal computers are still primitive. The excellent mico-DC20 enables high quality capture using MJPEG compression (not MPEG) to 768x576 (full PAL size) and the resultant edited material can be output using S-connectors. I have experience of the £1200+VAT Videologic Mediaspace that allowed images up to 1024x768 to be recorded direct to disk. Videologic's own YVU format gave the best quality, but it was far from Super-VHS/Hi8 quality. On the positive side there was at least no drop out and no tape related faults.
Getting information of add-on cards to computers is very difficult. I phoned and wrote to several manufacturers and suppliers of multimedia systems with three simple requirements:-
As a typical computer has up to 7 slots of which four may be taken for Super VGA graphics card, SCSI interface, ethernet and fax/modem that leaves three slots for :-
If CD-R and or scanners are added then a dual SCSI adapter or a second SCSI card may be required.
With DVC it should be possible to connect to a computer using the new high speed data protocol. This has been designed for multimedia (audio, video and graphics) and is capable of higher transfer rates (Firewire or IEEE 1394 standard) than any of the current I/O standards (serial, parallel, IDE, Ethernet or SCSI). Transfer of camcorder video to computer should be faster than normal play back time. No conversion is required from analogue to digital (as will current Hi8 and S-VHS) and no additional compression is needed (such as MJPEG or MPEG). Such a card for a PC should be a fraction of the cost of the micro-DC20 or similar cards from FAST (<http://www.kardengroup.com/fast.htm>), Videologic and others. And, as no conversion is required, the resulting 'capture' video will be the original. The same card could provide digital input from a DAT or CD player and output to a hi-fi DAC or DAT recorder. As editing would be in the digital domain the six cards required above could be reduced to one with two plug-in daughter cards (MJPEG and MPEG compression). However I guess these cards will retail at thousands of pounds.
After editing, adding titles, etc. the video can be dumped to DVC (via a digital connector) or to a recordable version of DVD (as many copies as you need). The DVD should be capable of being viewed on any compatible computer system (most) as it is no longer dependant upon TV format standards. The output, the copy created, will be as good as the alterations (titles) that have been made with all unaltered sequencing being identical to the original (no conversions having been made). The nth generation being as good as the original is every camcorder user's dream.
This new wonder domestic digital format is still not good enough - Sony have announced a professional format with a track width 5 micrometers wider than the domestic version and the shoulder mounted camcorders will record three hours of footage on a standard DVCAM cassette (<http://www.mitl.research.panasonic.com/nabsite/dvcpro/dvcpro.html>). At least high speed editing decks and edit stations based upon PCs running Windows 95 and NT have been announced at the same time. Another cassette size, another data rate, another format.
I wonder why fractal compression of video has not been adopted. M-JPEG is motion JPEG (the loosy compression standard for still photographs). MPEG takes this a stage further by only storing the difference between frames with periodically including a complete frame. This is why MPEG has higher compression than MJPEG and why more processing power is needed. Fractal compression rates are in excess of 100:1 (10 times greater than with MJPEG and MPEG). Also they require less processing power to decompress than compress. Fractuals work on mathematical formulae and decompression forms the image in progressive stages of resolution. More like bringing an image into sharper focus. The more processing power the greater the resolution achievable in real time. Playback systems are cheaper than recorders.
Besides a sizeable collection of LPs and compact cassettes, I have hundreds of V2000 2x4 tapes and hundreds of Hi8 HME120 comprising mainly of Science fiction and comedy TV programs, and a fair number of movies. The 1984 V2000's picture quality is as good as my newer JVC S-VHS using standard tapes but I record mainly using S-VHS and Hi8. The drop out and tape faults on the V2000 are less than with the 'repaired' (new video head) Sony EVS1000 or the brand new Sony EVS9000. Transferring my V2000 collection would take over 1 year (24 hours per day, 365 days per year). With the Hi8 collection and few VHS tapes I would have something like 2 years of continuous playback to transfer at an original cost of about £21000. With DVC costing about £18 for a 60 minute tape that means spending out £200,000 on new cassettes! Practically and financially an impossible task.
Are collections going to be made redundant by the hyped Internet and super hi-way? I am sure that if video upon demand takes off then so will audio upon demand and programmes (television and radio) upon demand along with interactive multimedia computer programs. Ethernet and disk drives are typically capable of 10 Mbits per second (68 minutes to transfer 4.7Gb DVD) with 100 Mb per second becoming more common. however, the fastest afford telephone line at the moment is ISDN which delivers up to 64 Kilobits per second (182 hours to transfer the 4.7Gb DVD). With multi-channel telecommunications and improved transfer rates it is technically possible to use a portable communicator (mobile phone with steroids) to dial up a selection of music (film, book, program, etc.) from anywhere in the world, whilst out walking or driving or from the comforts of your own home. The entire resources of the television boardcasters, radio stations, publishers, museums and libraries could be made available for a royalty, provider and a transfer fee. No personal collections required, no pirated copies... Except... Since the 'owners' of such material refuse to allow the same film format to be distributed in North American as the rest of the world and want to further divide the European Community up there is no hope of getting any agreement for the foreseeable future.
If such Internet services of entertainment upon demand where brought about people would still want to take still photographs and record movies and write letters. But perhaps all these could and would be stored on or transferred to their domestic computer system and hence become a personal service provider also accessible from anywhere in the world.
At least, having gone digital, conversions to a new formats is a simple matter of software, system capacity and processing time.
Canon's main European Headquarters <http://www.europe.canon.com/corpinfo/>
Grundig Home Page <http://www.grundig.com/>)
Welcome to JVC home page! <http://www.jvcservice.com/>, <http://www.jvc-victor.co.jp/>
Panasonic Home Page <http://www.mitl.research.panasonic.com/>
Philips Home Page <http://www.philips.com/>
Welcome to Sony Electronics Inc. <http://www.SEL.sony.com/>
SCART Connector <http://www.netstorage.com/kjack/ scart.html>
S-Video Connector <http://www.netstorage.com/kjack/ svideo.html>
Skipstone - the IEEE-1394 Serial Bus Experts <http://www.skipstone.com/>
The GFG home page
Last updated 31st July 1996