BYTE SIZED
D. W. Leitner on the next wave of digital video equipment
- Digital Video (VERSATILE) Disks -- DVD
Apple's FireWire
DV and FireWire: How Good Is It?
DV Camcorders: Consumer and Professional
The Demise of Analog Video
Cross consumer Hi8 and top-shelf professional D1, and what do you get? As Paul Simon once sang, days of miracle and wonder. Not that the recently introduced DAT-like consumer DV format (Digital Video) is a panacea. The camcorders are pricey, units are scarce and accompanying playback decks and edit systems are not yet ready for prime time. But for Sony, Panasonic, JVC, Thomson, Philips, Hitachi, Toshiba, Sharp, Mitsubishi, Sanyo, and 45 other companies who finalized the format in December 1994, marketing digital component video production to the masses is crossing the Rubicon into the commodification of what's been, up until now, the jewel in the crown of high-end production. And there's no turning back.
Last year, for instance, sales of DSS (Digital Satellite System) geared to U.S. consumers took off like a rocket. Eighteen-inch satellite dishes and tv-top receivers for reception of compressed digital MPEG-2 signals from DirecTV and USSB were the fastest selling new products in the history of consumer electronics. Faster than VCRs, CD players, Walkmans, you name it.
If the public's love affair with clean, pristine digital images accompanied by CD-quality audio has finally begun in earnest, this year, coincidentally or not, is shaping up as a watershed for digital video in general - a veritable dam burst, if you will, of new devices and directions.
Digital Video (VERSATILE) Disks -- DVD
1996 will witness the inauguration of prerecorded films on CD-sized Digital Versatile Disks or "DVDs" (you and I will call them Digital Video Disks). DVDs not only doom VHS but also CD-ROMs as we know them for the mere reason that single-sided DVDs store 8.5 gigabytes compared to the puny 680 megabytes of CDs while manufacturing costs are the same.
Then there's the one-two punch of DV and FireWire.
In the flush of excitement over the first consumer digital video camcorders from Sony and Panasonic (described below), the larger significance of DV has been overlooked. The agreed upon DV standard represents more than just a 6.35mm metal tape format and family of cassettes. DV is a totally new real-time compression algorithm with an inexpensive double chip set to encapsulate the necessary compression/decompression technology. Since DV's 5:1 compression scheme is optimized for both camcorder and nonlinear editing, DV poses a direct challenge to the Motion JPEG standard widely used today in all nonlinear systems. The chip set's low cost ensures DV's presence in many devices, including upcoming video boards for PCs.
back to top
Apple's FireWire
There's more. For a couple of years Apple Computer has touted the potential of a hot new technology to replace the thick 25-pin and 50-pin SCSI (Small Computer System Interface) cables that connect hard drives to computers. No slackers in multimedia, Apple has sought to standardize a new IN/OUT high-speed serial bus technology that would be small, cheap, and lightning fast in the transfer of copious amounts of data needed for real-time exchanges of large QuickTime files and compressed video.
Internationally standardized as IEEE 1394 (Institute of Electrical and Electronics Engineers) and trademarked FireWire by Apple, the new interconnect technology debuted a few months ago - .If you look closely in the lower right corner at the rear of either of the new Sony DV camcorders, the one-chip DCR-VX700 or three-chip DCR-VX1000, you'll see a little connector half the size of a modular telephone jack marked "DV Out." Don't let size fool you.
Containing only six fine wires, FireWire looks fragile next to a SCSI cable, but it's bi-directional with simultaneous signals flowing over each single wire, and it supports up to 63 daisychained devices (compared to SCSI's eight), eliminating conflicts by automatically assigning the devices IDs (no termination required) and distributing up to 60 watts of power to those which are "hot-pluggable," sans power cords. FireWire hosts multiple computers too.
How fiery is it? Your modem probably does 14.4 Kbps (kilobits/second) over a common telephone line. SCSI permits a maximum sustained data rate of five Mbps (megabits/second), about 350 times faster. The current supercharged SCSI-2 Fast/Wide standard with huge 68-pin or 80-pin connectors maxes out at 20 Mbps, while a newer protocol, Ultra SCSI, doubles that. FireWire, however, currently achieves one of three rates - 100, 200, or 400 Mbps - with 800 and 1,600 Mbps expected in 1997. Sony's DV camcorders output only 100 Mbps, 7,000 times faster than your 14.4 Kbps modem.
FireWire, or more properly, IEEE 1394, is part of the DV standard embraced by the 55-company DV consortium. Officially designated "DV Interface," it specifies throughput protocols for digital audio, digital video, control and auxiliary data over a single IEEE 1394 cable with a standard DV connector. IEEE 1394 is also emerging as a general multimedia interface for scanners, digital still cameras, and VCRs, and is poised to replace MIDI with it's capacity for simultaneous multiple streams of digital audio and MIDI-style control codes.
Expect FireWire video boards later this year and Macs with built-in FireWire ports by year's end. In the meantime fantasize about directly downloading your DV camcorder into your Mac and clicking the Adobe Premiere icon. "Look Ma, no digitizing."
back to top
DV and FireWire: How Good Is It?
For consumers, DV and FireWire remove the last vestiges of analog signals. But to what end? How good is it? In fact, DV is true component digital video - not quasi-component like Y/C or S-Video - recorded at 4:1:1, eight-bits, 5:1 compression, with two to four channels of 12-bit/32kHz digital audio, or two channels of 16-bit/48KHz that exceed CD-quality, depending upon camcorder design.
(Quick Techie note: computers output simple RGB signals - red, green, blue - but for reasons of history and bandwidth conservation, video rearranges RGB into three "component" signals: one luminance and two chrominance.Component digital video signals are described by numbers that look like "4:2:2." 4:2:2 refers to the digital sampling rates of, respectively, the luminance signal and the two chrominance signals. Basically, 4 represents full sampling and reproduction of the original signal, 2 equals a sampling at half the full rate, and 1, a quarter rate.
Digital component video for compositing and effects is sometimes 4:4:4, but its conventional high water mark is D1, which is 4:2:2. The 4:2:2 standard, incidentally, was created in 1982. D1 was born in 1985. Both, counting technology years, are long in the tooth.)
DV, being 4:1:1, samples its luminance signal at full rate. As a result, DV's picture sharpness - solely a function of luminance - equals D1 and Digital Betacam, both of which are 4:2:2. DV and Digital Betacam formats, for instance, are rated both at 500 lines of horizontal resolution (NTSC's transmission limit is 334). Further, despite its 1/4 chrominance sampling, DV's chrominance bandwidth, 1.5 MHz, matches Betacam and Betacam SP. Does that mean consumer DV outperforms professional Betacam SP? Do the math again.
What's more, like all digital audio and video formats, DV has built-in error correction. Drop outs? Digitally masked. Generational degradation? Each copy a clone of its parent. Digital video mercifully obsoletes these and other prevailing analog maladies.
back to top
DV Camcorders: Consumer and Professional
To date, Panasonic, Sony, and JVC have introduced consumer DV camcorders (some wearing a "prosumer" fig leaf), while Panasonic and Sony have introduced rival professional versions of the format, respectively DVCPRO and DVCAM.
Three-chip consumer DV camcorders from Panasonic and Sony, the AG-EZ1U and DCR-VX1000, feature high-resolution color viewfinders, 10x optical and 20x digital zooms, 1/3" CCDs with 410,000 pixels, image stabilization (I prefer Sony's optical Variable Prism system to Panasonic's digital compensation), timecode (proprietary drop-code for Sony, SMPTE for Panasonic), and street prices between $3,500 and $4,000.
About $1,000 less are Sony's one-chip DCR-VX700 (410,000 pixels), which otherwise resembles the DCR-VX1000, and JVC's one-chip GR-DV1 (570,000 pixels), which resembles... an overgrown Zippo. Self-styled "world's smallest camcorder," the JVC GR-DV1 is 1-11/16" x 5-13/16" x 3-1/2" and 1.1 lbs. with tape and battery - smaller than a Betacam cassette. Holding it upright like a cigarette lighter, you practically expect a flame when back-cocking the sliding electronic color viewfinder to put it in standby. It even has a docking station to create slo-mo and other digital effects in playback. Maxwell Smart, eat your heart out.
Such Lilliputian dimensions are made possible by the matchbox size of the Mini DV cassette, available in 30 min. ($20) and 60 min. ($25) lengths. The Standard DV cassette, about 3" x 5", not yet available, holds over four hours. All DV cassettes have an embedded ID chip that tells the camcorder the tape's type, thickness, and grade, but some DV cassettes, such as Sony's, feature a larger 4Kb memory chip. Sony DV camcorders read and write to "cassette memory" a "table of contents" of dates and times of video and Photo Mode recordings (the DV format provides for the taking of high-quality digital stills).
Outstanding DV issues include fears of political grandstanding by copyright protection watchdogs, which could hobble or even scuttle DV - and the conflict between the rival professional designs, in both senses, of Sony and Panasonic.
Memories remain fresh of the fierce '80s debate on digital home recording that almost torpedoed DAT and inspired Congress to take legal action and impose compensatory tariffs on consumer digital recorders and recording media. DV manufacturers know the MPAA's Jack Valenti lurks in the wings. What else explains the absence of analog inputs on any of the new DV camcorders, or digital inputs/outputs altogether on Panasonic's and JVC's? By contrast Sony's implementation of FireWire for digital input/output appears bold. However a tiny footnote at the bottom of Sony spec sheets warns: "Recording to and from the Digital Video Cassette Recorder may be limited by a copy management system."
The first professional ENG version of DV surfaced a year ago at the 1995 National Association of Broadcasters Convention when Panasonic, joined by BTS, announced DVCPRO. Panasonic showcased working models of a fully featured ENG camcorder, the AJ-D700, and studio record deck, the AJ-D750. Promised was an upcoming compact field recorder, laptop edit system, and high-speed player for "streaming" DVCPRO tapes at 4x record speed to a nonlinear editing system-the first appearance of high-speed digital video downloading, considered a must for new digital video formats.
Why a professional version of DV at all? 1) DV's tiny video tracks, 10 microns wide, are too thin for reliable editing accuracy, 2) DV timecode, as specified in the DV standard, is purportedly accurate only to +/- 1 frame, unacceptable to professionals, and 3) professional tape and cassettes require robustness and tighter manufacturing tolerances.
Panasonic's DVPRO widens the recorded tracks to 18 microns, adds SMPTE timecode yet retains "upwardly compatible" with DV. DV cassettes, in other words, play on DVPRO machines, but not vice versa. DVPRO utilizes medium-size DV cassettes that record a maximum of 63 minutes and standard cassettes for 123 minutes.
Enter Sony, gloves off. At this year's NAB in April, Sony debuts DVCAM, with enlarged 15 micron tracks, yet total compatibility with consumer DV. DVCAM mini-cassettes yield 40 minutes, standard cassettes 184 minutes. (DVPRO and DVCAM camcorders primarily use the larger "standard" cassette.)
DVCAM cassettes incorporate 16Kb chips, four times more memory than consumer DV cassettes. Why? "ClipLink." ClipLink enables a videographer using a Sony DSR-200 one-piece DVCAM camcorder or two-piece DSR-130 to select, while still on location, best takes for later downloading at four times speed to Sony's new ES-7 nonlinear EditStation, thereby reducing transfer time and necessary disk space. Needless to say, the DSR-200's digital in/out is FireWire, and the ES-7 EditStation's compression, DV.
In addition to premiering DVCAM camcorders, cassettes, decks, players and nonlinear EditStations at April's NAB, Sony is introducing... yet another component digital format! Intended for news and other fast-paced broadcasting, Betacam SX is 4:2:2, 8-bits, 10:1 compression, and incorporates an altogether different original compression scheme, "4:2:2 Studio Profile." The clutch of new products surrounding Betacam SX includes Betacam-style camcorders, players, recorders, and nonlinear systems for 4x downloading, offlining, onlining, and live editing. Included, as well, is the world's first Digital Video Hybrid Recorder, a tape drive and video-capable hard disk combined into one unit.
Where does all this leave last year's compressed (2:1) component 1/2" format, Digital Betacam? Or classic component D1, for that matter? Or composite D2, 1/2" composite D-3 (there is no D-4... in Japanese lore, "4" evokes death), 1/2" uncompressed component D-5, Ampex's component DCT, or... JVC's new Digital-S, tossed into the swollen ring this April at NAB? An economical editing format meant to look and feel like S-VHS, Digital-S recycles the familiar VHS cassette once again, this time to house 104 minutes of component digital video recorded at 4:2:2, 8-bits, 3.3:1 compression, with 2 channels of 48KHz, 16-bit CD-quality audio.
back to top
The Demise of Analog Video
Rumors of the demise of analog video - video as we've known it - are no longer exaggerated. However gird yourself for a more complex world. The days of connecting 3/4" decks to a Sony 450 controller and starting to edit - akin to "plug and play" in the Macintosh world - are over. With the proliferation of digital standards, platforms, interfaces, drivers, connectors, etc., all orchestrated by software we don't see or understand, the dreary task of interfacing digital video devices from different manufacturers will likely approach frustration thresholds traditionally associated with adding boards and peripherals to DOS computers. Even days of miracle and wonder come at a price.
VOD CALENDAR
See the VOD Calendar →
