"One" advantage of Digital 8

[Sillyname]

For some reason she squeals when she goes over speed bumps...

[mynx]

Not to continue a heated arguement, but I have learned that the major difference between DV and miniDV is miniDV has a much higher dropout rate. This is do to the much smaller tape. So its very likely true that D8 has a lower dropout rate. Wether or not you can see this I don't know. It may be corrected by the circuitry. I don't have any hard numbers and doubt that any would ever be released to the public.

[Dr Mordrid]

Well...that's not really the case.

There is no difference between DV and miniDV from the tape standpoint, both are 6.3mm ME tape on 21.7mm drums. The differences lie in tape length, transport speed and a difference in the track pitch used.

Also, even though the D8 tapes are larger they are moving through the tape mechanism at double their design speed (that used by 8mm & Hi8), which also happens to be ~52.5% faster than DV/miniDV is transported. Here's the rundown;

8MM: 14.345 mm/s
Hi8: 14.345 mm/s
DV: 18.81 mm/sec
D8: 28.7 mm/sec

Dr. Mordrid

[Brian Ellis]

Mynx

Can you provide any supportive scientific evidence for this hypothesis? I suspect it may simply be one of those commercially generated falsehoods told by a dealer trying desperately to sell off his quota stock of D8s. Being a confirmed sceptic and seeing no reason why it should be (rather the contrary) and not having seen any drop-outs in practice with 3 years' fairly intensive experience of mini-DV, please permit me to revert to my former statement CODSWALLOP, until proof to the contrary.

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Brian (the terrible)

[mynx]

Brian Ellis: I am a camcorder repair technician. I can verify you will never "see" a dropout in any digital tape format. After the tape is read the picture is stored into memory then sent out as video. If a dropout occurs the memory for that pixel will stay at its previous value. This can be verified easily. When you scan there are spurious blocks of video that appear. This is where the new data was lost so the last data still remains. This also is very obvious with a dirty head were you get alternating bands of new video vs a memory picture. The requirement for testing these camcorders is to view a moving scene or we can never find the problem. A bad heads can produce a perfect still picture.
Dr. Mordrid: I'll verfy this with a friend that works at a TV station, but I had read otherwise. I don't remember where so, if I'm wrong I stand corrected.

[Patrick]

The argument that never dies...

...even though the D8 tapes are larger they are moving through the tape mechanism at double their design speed (that used by 8mm & Hi8), which also happens to be ~52.5% faster than DV/miniDV is transported.

Doc, we've been down this road before. I'd like to see some evidence that 8mm tapes have a "design speed" and that they are somehow incapable of recording and playing back at twice the speed they are used at in 8mm and Hi8 units. Are you trying to suggest that these tapes don't have the durability to be rewound or fast-forwarded in 8mm or Hi8 equipment? I think not. I also don't understand why you appear to suggest that it is somehow a negative thing to have a faster recording and playback speed. Perhaps it isn't as necessary in the digital domain, but with any analog recordings, it is always preferential to record at faster speeds in order to maintain the highest quality. Do we at least agree on that?

I suspect it may simply be one of those commercially generated falsehoods told by a dealer trying desperately to sell off his quota stock of MiniDVs.

Oh, sorry Brian, did I not get the quote quite right?

mynx, I've seen the symptoms you've described during playback of a friend's digital tape. There was "freezing" of the video in certain spots. Apparently this is a digital dropout. Interestingly enough, this was a tape recorded with a Sony VX1000 MiniDV camcorder. I have never seen this occur yet with a Digital8 tape. I'm not saying it won't occur, just that I've never witnessed it yet. (I'm in the unique position of being able to see video footage from all kinds of camcorders because of my involvement in an amateur video production club.)

I say we give that round to the Digital8 camp...

[Pooh]

ding ding, round 3


Pooh

let's keep it friendly guys

[paulw]

It's Monday. Gee how the weekends go.

Brian.

Thanx for the Sleeping Policeman. Yes we do have them in the "antipodean" areas. depends upon the city you live in. Called "speed humps" here.

[Brian Ellis]

Sorry, thought a 'speed hump' just occurred in the cheapest red light districts

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Brian (the terrible)

[This message has been edited by Brian Ellis (edited 11 September 2000).]

[Frank Marshall]

We know these "sleeping policemen" as "silent coppers" in Australia; they're common in country towns. Rather than plain speed bumps/humps, these are steel, button-shaped pikes about a foot in diameter and a good six inches high. They're typically bolted into the middle of roads at approaches to intersections to deter drivers from cutting corners. It's a nasty business as they're difficult to see at night, even if they are painted yellow... I've never seen a hit but I'd imagine it would be quite spectacular.

[This message has been edited by Frank Marshall (edited 12 September 2000).]

[Sillyname]

Just gotta pick on you Frank...

But you wouldn't happen to be "the" Frank Marshall of Kathleen Kennedy/Steven Spilberg fame, would you?

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Deep is not the root word of depression.

[Brian Ellis]

To restart the serious debate, I came across the following today. This was on the Canon site and, as they make both Mini-DV and Hi-8, I suppose they should know. My apologies for not re-formatting the text.


The digital video standard uses an entirely new
tape structure and formulation. Although there
are some similarities with certain Hi-8 tapes,
digital video tape is superior, made to last
longer, and better able to stand up to repeated
use without failure. Because of the way the
internal mechanisms of digital video equipment
work with the tape, digital video tape is stronger
than Hi-8 tapes, and much stronger than VHS
tapes.

DVC tape is an advanced form of metal
evaporated (ME) tape. While ME-type Hi-8 tape
is the best in that format, the ME tape used in
digital video is superior. The magnetic layer is
double coated to give higher output and less
noise. A hard layer of carbon is placed over the
magnetic portion of the tape to give maximum
protection and prevent the tape from wearing
out over long periods of use. It's the same idea
as applying black topping to a driveway; the
black topping helps protect the underlying
surface, helps prevent damage to it. As well, a
new type of back coating is applied to the tape,
reducing friction, providing more stable tape
movement, and reducing jitter.

Digital video could not work without DVC ME
tape. It allows the recording of a large amount of
data, with higher output and lower noise, and
protects the data with a protective coating and
friction reduction. Digital video would be
impractical without this new tape formulation.

Comparing tape widths: VHS tape is 1/2-inch
(12.7 mm) wide, 8 mm tape is 8 mm (slightly
less than 1/3-inch) wide, and DVC tape is 6.35
mm (1/4-inch) wide.

5.7 Handling precautions
The precautions for handling digital video tape
are not that much different from any tape
product (video or audio). The main ones are:

Day to day

1.Do not touch the tape
2.Always put the cassette in its case
3.Do not subject the tape to shock or impact
(dropping it)
4.Do not expose the tape to strong
magnetic fields
5.Do not leave in a car (because of the
heat, cold, vibration)
6.Do not use the tape if it has gotten wet or
has had anything spilled on it
7.If the cassette is cold, let it warm up for at
least 2 hours before using
8.Do not store the cassette in hot, humid or
dusty locations
9.Do not leave the cassette in the DV
recorder
10.Never disassemble the cassette

Long term storage

Follow the Day to Day rules plus

1.Always store the tape vertically, tape
rewound, and the tape in its case
2.If you are storing for a long time,
occasionally fast forward and rewind the
tape.

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Brian (the terrible)

[Grigory]

Digital video could not work without DVC ME
tape .

Sounds well, but... D8 works on regular tapes. I have found one single frame dropout for 1.5 years: it was in the beginning of clip, within 10 frames from pressing START button. The droppped part of image was substituted by previous field. The sea level was broken in this frame, because the camcorder was moving up. The reason of dropout was probably not perfect tape motion at the start. I used this piece once again - there was no tape defect.
All other tapes did not show any dropped fragments.
I use TDK EHG video 8 tapes and BASF HiFi video 8 tapes.
Once I read somewhere that most manufacturers are probably making all regular 8 tapes in the same way as Hi8 MP, because one production line is cheaper than two. That is why nearly all high quality 8 mm tapes and VHS-c tapes work fine as Hi or S tapes, if you take care about the holes...

The conclusion: although I am not taking special care about the tape storage, but just use them in cold, wet, hot, dusty, salty, rainy environment, they can reproduce DV video well for 1.5 years after 5-10 passes through the camcorder and in the points where the PAUSE was used until the shutdown. Well, miniDV tapes as DV storage have longer history, so D8 users cannot say anything about long term durability - let us see.

Grigory

[Sillyname]

---------------------------------------------
Digital video could not work without DVC ME
tape.
---------------------------------------------

What a goofy statement...

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Deep is not the root word of depression.

[Sillyname]

Grigory, you beat me to it!