The Time Machine
Disks offer many advantages. So why do we still use tape-based camcorders?
What do the Marx Brothers and John Lennon’s widow have to do with the technology of videography? Perhaps not much — yet. But, although scientists have yet to prove it, it could well be the case that an onosecond is shorter than either a harposecond or a grouchosecond. And this year could be one of the last in which onoseconds are associated with camcorders.
In the United States, we tend to measure distances in inches, feet, yards, and miles, even though most of the rest of the world uses meters. Yards are comparable in size to meters, but miles and inches are not. To deal with larger and smaller distances, the metric system offers prefixes. A kilometer, a thousand meters, approaches the length of a mile; a centimeter, a hundredth of a meter, is a substantial fraction of an inch.
Throughout the world — even here — the second is the basic unit of time, and it takes the same prefixes. Consider videography.
The optical principles of the camera were described over a millennium ago. That’s almost 32 billion seconds, or, to use the metric prefix, 32 gigaseconds.
The word television was coined in 1900, more than a century, or about 3.2 gigaseconds, ago. The camcorder was introduced in 1981, a little over a score of years ago, or roughly 700 megaseconds (million seconds).
Sony introduced Digital Betacam, the first component-digital camcorder format, a decade, or roughly 316 megaseconds, ago. The camcorder format with the smallest videotape cassette, MicroMV, was introduced about 20 months (some 52 megaseconds) ago.
Like those of other American-standard camcorders, each frame from a MicroMV image lasts about 33 milliseconds (thousandths of a second). Each scanning line lasts about 64 microseconds (millionths of a second). A single digital-component picture element (pixel), sampled according to International Telecommunications Union recommendation BT.601 (the basic digital-component video standard), lasts just about 74 nanoseconds (billionths of a second). A single wave of the light that entered a camera lens to create that pixel might take just 1.33 femtoseconds (thousandths of trillionths of a second) to go through its cycle.
The metric system offers pico- between nano- and femto- to represent trillionths, and, beyond femto-, atto- to represent millionths of trillionths. A parsec is a vast astronomical distance that would take light in a vacuum more than three years to traverse; an attoparsec is a little over an inch. We measure tape speeds in the U.S. in inches per second; almost the same figures would apply to attoparsecs per microfortnight.
A need for prefixes beyond even millionths of trillionths led the 19th General Conference on Weights and Measures to add more in 1990. Atto- is the prefix representing a thousand to the negative sixth power, so the committee considered using the Latin septo- to represent the negative seventh power (billionths of trillionths) and octo- for the negative eighth.
Unfortunately, someone might think an octosecond is eight seconds or an eighth of a second rather than a trillionth of a trillionth of a second, and the resulting abbreviations were also thought confusing (ss, for example, for septosecond), so the prefixes were modified slightly. A billionth of a trillionth is zepto-; yocto- is a trillionth of a trillionth. That way, future prefix abbreviations can work their way backwards through the alphabet.
The scientists at the 19th General Conference seem to have thought of everything — except the Marx Brothers. Zepto- is pretty close to Zeppo. By 1993, harpo- was suggested (humorously) as the prefix representing a thousand to the negative ninth power and groucho- as the one for the negative tenth. If chico- and gummo- came next, quantities as small as trillionths of trillionths of trillionths could be easily described.
One gummosecond, therefore, would be a time interval so short that, if you had a trillion of them, they’d still take up only 0.000000000000000000000001 seconds. Some, however, would argue that an onosecond is even shorter. An onosecond is typically defined as the amount of time between hitting the Enter key on a computer and realizing that you didn’t really want to do that (“Oh, no!”).
A broader definition would take in other regrettable actions or even inactions. In videography, an example of the first might be erasing an irreplaceable tape; an example of the second might be neglecting to hit record in the first place, though it might not be directly related to neglect.
Consider a news crew covering a three-hour political event. Perhaps the agenda says that the big speech won’t occur until the last hour, and a copy of the speech shows that its highlight won’t occur until the last five minutes.
It would be silly to start recording at the beginning of the event. Camcorder tapes don’t last for three hours. Even if they did, an editor would have to wade through hours of useless material to get to the speech highlight. Common practice in news coverage is for tapes to roll just before the highlight, with perhaps a few other tidbits here and there.
If at this particular event, however, the top politician suddenly has a pang of emotion, grabs the microphone ahead of schedule, and blurts out the sentence of a lifetime, chances are that all the news crews present would race for their record buttons and reach them at least one onosecond too late. The only hope would be a time machine that could whisk the news crews back to a moment before the great revelation, when they could hit record and get it all.
Fortunately, such a time machine exists. The only question is why more videographers don’t use it.
Some people say the writer Jules Verne anticipated video recording in The Mysterious Island in 1874. Even if true, that shouldn’t come as too much of a surprise. Both motion-picture toys and photography were common by then, and the idea of combining the two had been proposed by well-known scientists at least as early as 1849. The same year The Mysterious Island was published, Verne’s fellow countryman, the astronomer Jules Janssen, built what some consider the first movie camera.
Verne (A Journey to the Center of the Earth, Twenty Thousand Leagues under the Sea) is sometimes confused with H. G. Wells ( The Invisible Man, The War of the Worlds), who also began writing science fiction in the 19th century. Wells may have been the first to envision human control of time, beginning in his Time Traveler stories and then in his 1895 novel, The Time Machine.”
Today, of course, we have plenty of machines that can record video. And today, of course, if someone has come up with a machine by means of which a human being can travel backward and forward in time at will — the sort of time machine in the Wells novel — then it is a well-guarded secret. As far as videography is concerned, however, there are time machines.
Perhaps it would be best to start at the beginning. That could be June 27, 1922, when Boris Rtcheouloff filed an application for a Russian patent for a videotape recorder. Alas, the invention was unworkable, and neither magnetic tape nor video yet existed. It wouldn’t be until 1956 that the first videotape recorder would be sold.
Video, in the form of a recognizable image of a face, was first seen in 1925, the same year that the first workable form of video recording was proposed at Bell Telephone Laboratories. It involved recording images on film, transmitting them electronically, and then recording them on film again at the far end.
John Logie Baird, the inventor who came up with that first recognizable video image in 1925, came up with another form of video recording. His initial video signals were so lacking in detail that they had no more frequency range than audio signals. So Baird simply recorded them on phonograph disks. A highlight of the Hollywood Post Alliance Technology Retreat in February was the playback of images from such a 1927 videodisc recording.
Even less well known is the patent application Baird filed in 1927 for a magnetic videodisc recording system and one of its uses. It was to be able to record at one rate and play back at another, suggesting faster-than-real-time transfer speeds.
Although a patent application for a color video recorder based on optical-disk technology was submitted as early as 1929, it would be some time before a videodisc recorder would be sold. In 1965, a company called MVR demonstrated a magnetic-disk-based video recorder that could capture up to 20 seconds of electronic moving images, with the ability to play back any portion instantly. CBS, which began using fast-processed film recordings for slow motion replays in football games in 1962, started using the MVR VDR-210CF on the air within a month of the demonstration.
The disk recorder continually recorded video. When it was stopped, the previous 20 seconds were available for replay. It was, in effect, a solution to the onosecond problem of neglecting to hit the record button in time — but only if the desired sequence lasted no more than 20 seconds.
MVR added slow-motion playback in 1967, and Ampex added color, reverse, and another ten seconds later the same year. Now the onosecond problem could be eliminated for events that lasted as long as half-a-minute, if one had a large disk recorder handy.
Fortunately, size wasn’t much of an issue at the time. The CMX 600, the first disk-based non-linear editing system, introduced in 1971, increased capacity to almost half an hour by dropping back to black-&-white, reducing detail resolution, and using six disk drives, each about the size of a dishwasher.
Why would editors be willing to use such a low-quality, gigantic device? It provided essentially instantaneous access to any point in the stored material, something we take for granted today but that was almost as unheard of even in 1988 (the year before Avid) as it was a century earlier, in 1888, when Oberlin Smith wrote of a recording system “that if some small portion of the record near the middle has to be repeated there is a good deal of unwinding to get at it.”
The known advantages of videodisc recording by 1971, therefore, included random-access (CMX), continuous recording (MVR), variable-speed motion (Ampex), and even faster-than-real-time transfer (Baird). There were disadvantages of size, quality, and cost, but those were traditionally taken care of with time. The first videotape recorder, in 1956, was huge and expensive and produced poor-quality black-&-white images; by 1971, there was a color, tabletop unit designed for home use.
Perhaps the advent of the camcorder in 1981 killed research into improved disk recorders. It’s one thing to imagine the size of a half-hour recorder dropping from six dishwashers to three or even one; it’s quite another to imagine it dropping to something weighing just a few pounds attached to a shoulder-mounted camera.
Nevertheless, that’s exactly what Avid and Ikegami introduced with the first disk-based camcorder (CamCutter/Editcam) in 1995. It used a magnetic disk-drive pack that cost $2500 — quite a lot compared to any camcorder tape — but it allowed instant non-linear editing, continuous “loop” recording to eliminate the onosecond problem, the ability to edit in the camera, and more. It was not a runaway success.
Hitachi and NEC introduced optical-disk-based camcorders a few years later. The disk cost was dramatically lower than that of the Avid/Ikegami product, but those disk-based camcorders didn’t take the industry by storm either. Neither did a smaller, lighter Editcam II.
This month, Sony is introducing another optical-disk-based camcorder, this time using a blue-laser recording system. Blue light (remember the 1.33 femtosecond period?) has a smaller wavelength than red light, allowing greater disk capacity. With essentially transparent 50-million-bit-per-second MPEG-2 coding, the disk holds 45 minutes of material; with DV-type coding, it holds 90.
In either case, the system records both high-quality and “proxy” video simultaneously. The low-rate proxy images can be sent from the field at 30-times-normal speed so editing can commence even before the disk gets back. Editing is also possible in the camera. And the onosecond problem can be eliminated through loop recording.
If not even it begins to take off, it may be time to check elsewhere for the problem. Perhaps exposed to bizarre prefixes (picofarads, nanoseconds, megabits, gigahertz, and terrabytes) for so long, videographers now have trouble dealing with simple concepts. In audio, for example, there are microphones and megaphones. If you think a trillion of the former equal one of the latter, seek professional help.