Last Updated 25 March 1998
UNDER
CONSTRUCTION
HELP WANTED!
The DV FUD BUSTER
Edited by Tony
Sutorius
Last Updated 25 March
1998
Contents
This guide is an attempt (well, lets say the beginning of an attempt) to combat a few of the more easily rebutted lumps of intellectual excrement that continue to clutter discussion of DV video. The information here comes from various sources, principally the excellent DigVid-L and DV-L mailing lists. Some of the information is credited to its original source, but in many cases this has not been possible... if in doubt, assume credit belongs with someone else. Thanks, guys!
Now, it is possible that some errors have crept in, so caveat emptor. PLEASE contact the editor if you spot anything incorrect or misleading. If something stays on here for a while, though, its been read by lots of people who really do know the answers, and they haven't alerted me to any problems. So, it just might be TRUE!
And a note for the gurus... I’d welcome any suggestions (and ESPECIALLY contributions) for new FUD that needs debunking... next time you get a bee in your bonnet, please put pen to paper and write us a “FUD Buster” section dealing to it. Together maybe we can constitute a little prick in the big bag of hot air that is, sadly, eclipsing the happiness of DV users everywhere... (ever been inspired by being described as a "little prick" before?!).
As editor, I’ll try to ensure everything here is as
accurate as possible, and fix anything that is shown to be wrong.
Information here is subject to informal “peer review”
from the wide range of experts in various areas who visitg this
website. Please help me de-FUD the FUD Buster!
BALANCE That exalted journalistic property which you may or may not find herein. To assist the unwary, any comments here that are definitely just my dumb old opinion are marked thusly.
DV Get a life, mate!
FUD Think “useless drivel”. Add your favourite “F” word. Or, for the less hysterical of adjective, Adam Wilt proposes the more traditional "Fear, Uncertainty and Doubt".
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By the way, if you're interested in New Zealand you should
definitely check out this
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FUD: DV isn't a professional format
Yeah, well... if you owned a hundred grand worth of Beta-SP gear, how keen would you be to see the competition shooting with $3000 camcorders and getting similar results?
DV is a format that has, despite the best efforts of its manufacturers to prevent it , gained widespread use in professional applications, ranging from wedding videos to broadcast documentaries. In my book that makes it a “professional format” in every sense that matters. While it's true that current equipment is somewhat lacking in the features that professionals need, like proper timecode, many of us are using it anyway because it lets us do things the old formats didn't, achieving very good quality for very low cost (compared to conventional pro gear).
OK, so a VX1000 or EZ1 won't produce pictures that look as
good as what comes out of a late-model Beta-SP model... but hell,
they only have 1/3 inch CCDs, and fairly shitty lenses. But they
really are close. And they really are cheap. This equipment is
allowing filmmakers around the world to make films that they
couldn't make before. I’d say that’s why traditionally
less technically oriented professional video people (like me, a
director/producer) are taking such an interest... this new
technology represents more than just a change of formats. Its a
change in how we can work, and what we can make. From a programme
maker's point of view, equipment doesn't have to offer the very
best possible technical specs to be the very best choice.
FUD: DV isn't “broadcast quality”
Ah, philosophy. If a tree falls in the forest but no-one hears it fall, does a bear shit in the woods? If DV is a widely used documentary and news television format around the world, is it ipso facto “broadcast quality"?
As anyone considering buying video equipment will know, there
is virtually not a single camera or format that someone,
somewhere will not describe as “broadcast quality”, and
that someone else will not violently disagree about. So, I can't
very well make a definitive statement. Put it this way... plenty
of broadcasters seem quite happy to broadcast the stuff. Draw
your own conclusions!
FUD: Nah mate, you’re confused! DVCAM and DVCPRO are the professional formats, DV is just a home format!
Well, this is a real old chestnut. Actually, there is SOME truth in this suggestion for DVCPRO... I’ll come back to that later. Meantime, some facts.
First, DVCAM. This is Sony’s “professional” version of DV, and many dealers and Sony reps make vague references to its inherent superiority. Fact is, though, the actual image data going to tape in a DVCAM camcorder like the 200 is THE SAME as what goes to tape in an equivalent DV camcorder (in this case the VX-1000 or VX-9000). That’s right, the same. Identical.
In fact, there are only three differences between DV and DVCAM.
First, the physical width of tracks on DVCAM tapes is wider (15nm compared to 10nm). Sony claims that this makes the format less prone to dropouts, and that it can be more accurately edited in linear tape machines. While both of these seem reasonable in theory, in practice the sorts of problems Sony suggest should plague DV machines have NOT been widely reported. My own experience is that the "dropout issue" in particular is actually complete non-issue. Your mileage may vary, of course, but bear this in mind. Also, consider whether linear tape editing is really how people are likely to use DV... the future is non-linear, right?
Second, the wider track width means that DVCAM recorders go through tape at 150% the rate DV does, though the tape is physically the same. A 60 minute DV tape goes 40 minutes in a DVCAM recorder.
The third difference between DV and DVCAM is the very first thing you'll hear from your Sony sales rep and relates to audio, specifically the way that it is synchronized to pictures. DVCAM equipment uses “locked” audio, where audio is directly associated with individual image frames. DV uses “unlocked” audio, where audio sync is controlled by a crystal oscillator, and in theory could drift slightly over very long shots, leading to a loss of sync, especially in editing. Once again, this sounds reasonable. Once again, there have been few if any reports of any problems actually presenting themselves with DV. In the hundreds of hours I've shot and edited, sound has NEVER slipped out of sync. Not once. Nada. Anyone out there seen it happen?
Adam Wilt, keeper of the DV FAQ, adds the following to the locked/unlocked audio issue...
So, are Sony's sales drones making up stories, or what? Well, until recently the locked/unlocked audio issue in particular prevented lossless digital “firewire” dubs between DV and DVCAM equipment, thereby maintaining a fairly wide and fairly artificial gap between their “professional” gear and their cheaper but virtually identical “amateur” gear. This has now largely gone away with the discovery of an undocumented function in DVCAM equipment that allows them to talk to DV gear. Why was this feature kept a secret by Sony? Hey, that sort of FUD is out of my league... draw your own conclusions!
Now, DVCPRO. This is Panasonic's “professional” version of DV. Unlike Sony, Panasonic are making their format “open”, available to other manufacturers. This strategy is showing signs of paying dividends, with major players like CBS investing heavily in the format, signalling confidence in its long-term viability.
Unlike DVCAM, DVCPRO offers some really significant enhancements over DV.
First, it has an analogue audio track on it, so that when it’s edited on a linear machine you can hear the sound whirring by while you’re spooling. This is kinda useful and, frankly, makes the edit suite a far cooler place to bring clients or potential girlfriends.
Second, DVCPRO tape has a different formulation from DV (any manufacturer) and DVCAM. Now, I’m NO kind of expert on tape formulation. Luckily my Australian colleague Merv Partridge is. Here’s what he says on the subject of “MP” Metal Particle tape (DVCPRO) versus “ME” Metal Evaporated tape (DV and DVCAM, all manufacturers):-
ME = cleaner picture [not relevant to digital formats, presumably -ed] but don't reuse tapes for pro work and never rock and roll for (linear) editing (except maybe a final cut) unless you want dropouts cos the ME surface comes off the backing more easily. i.e. the pro recommendation was use ME for shooting then dub to Betacam or something else for linear based edit decisions and maybe final cut.
Third, DVCPRO studio decks can (with an optional board) replay
DVCAM tapes as well as their standard DV and DVCPRO, and
output any to SDI (Serial Digital Interface, a older professional
4:2:2 digital transmission protocol). While neither of
these may be all THAT important in itself, they do demonstrate Panasonic's serious
commitment to creating a ubiquitous and open format -
a philosophy that Sony is, erm, less obviously enthusiastic
about.
Fourth, and maybe most important, DVCPRO is clearly winning the race for professional acceptance, as measured by major broadcasters committing to it. CBS, NBC, BBC etc etc etc can’t ALL be wrong, right? I’m picking that DVCAM may well become the 8-Track of DV formats… we don’t need three, and Sony’s continuing insistence on keeping all the DV’s as far away as possible from their more lucrative “professional” formats like Beta-SX won’t do DVCAM any good longterm.
Heh, I can already hear the lawyers sharpening
their pencils…
FUD: Sony tapes are better and worth the extra money because they have a little chip in them that records lots of important information, like white balance mode, shutter speed, timecode, date, time and stuff like that
I’m sick of this piece of misinformation. It sticks, because on the face of it it seems a reasonable proposition, and because it is often repeated by people who really should know better (like guys who sell a lot of Sony tapes!). But it’s WRONG WRONG WRONG!
All sorts of useful information IS stored on DV tapes, including white balance mode, exposure setting, shutter speed, time and date. This information is stored right on tape, as an integral part of the DV datastream. In other words, any DV tape stores it, chip or no chip.
There is a memory chip in some Sony DV tapes (chipless Sonys are also available). In standard Sony DV camcorders this chip stores the location on tape of the first shot on any given date, and the location on tape of any “photos” you’ve taken. These might be useful pieces of information for someone out there, but in shooting and editing over 200 hours of material on our VX-1000 I’ve never used it once.
Still don’t believe it? Well, consider this: All that
useful settings data is stored for each and every frame shot. On
a 60 minute NTSC tape that’s over 108,000 frames (90,000 for
PAL). On a 4KB memory chip? Don’t think so....
FUD: Well then, the chip stores something to do with marking shots “good” or “bad” for editing
Nope. You’re thinking of Sony’s
high-end dockable DVCAM cameras like the DSR-130. DVCAM tapes
from Sony come with a larger
16KB chip in them, designed to allow shooters to mark shots
“good” or “no good” in the field, so editing
is accelerated. Cool, eh? Unfortunately, this facility exists
only on the laptop tape edit suite, the ES7 “Edit
Station”. Did I say "exists"? Apparently it
doesn't actually work yet, but ANY DAY NOW. Really.
What you lookin' at?
FUD: OK smart guy, Sony tapes are better because of their superior chemistry
There's quite a bit of confusion about this. There's a discussion about the relative merits of ME and MP tape in the "DV Format Family" section above. Just remember, ALL standard DV tapes are "Metal Evaporated", regardless of manufacturer. So are all DVCAM tapes. Only DVCPRO tapes are "Metal Particle". So on this score at least there is no difference between different brands of standard DV tape.
Personally, I’ve used almost exclusively Panasonic DV tape, and had virtually perfect performance. Some people report excessive dropouts from them, but I’ve seen literally two or three from two or three hundred tapes (waaaaaay better than Beta-SP, in my experience). And, being digital, any tape that doesn’t drop out will produce identical video quality.
One interesting note from our friends over at AOL’s video SIG has come up (sorry, I’m not sure who wrote it):-
Their advice: Don't try to re-invent the wheel -- use Sony tape in Sony equipment, and Panasonic tape in Panasonic equipment.
This post is a little confused in thinking that Panasonic and Sony tapes are MP and ME respectively - they're not, as explained above. However, there are several reports of problems with mixing tapes from the two manufacturers because of conflicting chemicals used in lubricant coatings on the tape surface. It seems both manufacturers, I'm sure inadvertently, have created a poisoned chalice for anyone silly enough to dally with the competition's consumables...
It has been pointed out that the conclusion drawn by the Sony techs above is, well, a bit dubious... a better one might be to choose one or the other formulations, and use that exclusively in any DV equipment, whether Sony or Panasonic.
A personal observation… in the
last week I’ve seen two cases in which older VX1000s seemed
to react badly to having “different” tapes put into
them… that is, Panasonics into a machine usually used with Sonys, or visa-versa. This seemed to cause severe
dropouts, and in one case even audible screeching from the tape
transport. In both cases the problem disappeared when the
“right” brand was used, and in both cases the use of a
cleaning tape seemed to make no difference. Others have reported
similar experiences.
THE END (for now, anyway... write some more!)
Now that some of the larger lumps of FUD have been squelched underfoot, I suggest you look at the rest of this site, the DV FAQ and DV Central for more information about working with DV digital video!
