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Answerman - Why Aren't Master Tape Formats Used Everywhere?


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mgosdin



Joined: 17 Jul 2011
Posts: 1184
Location: Kissimmee, Florida, USA
PostPosted: Fri Nov 24, 2017 12:16 pm Reply with quote
I've walked into one of the local thrift stores and found that they had a Pro Betacam for sale, they didn't know what it was worth and neither did I. The $500 they had it marked at probably was less than the parted out value of the machine. With everyone dumping physical media there is a glut of DVD's & CD's available which makes for happy times for collectors like me. I keep copies of Music and Video on multiple redundant hard drives with a regular schedule of cycling them out every two years.

Mark Gosdin
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samuelp



Joined: 25 Nov 2007
Posts: 1990
Location: Tokyo, Japan
PostPosted: Fri Nov 24, 2017 12:37 pm Reply with quote
One other thing to keep in mind that the question person might not have realized:
All modern tape formats are digital, not analogue. Digibeta and onward are pure digital formats internally, and are basically just very specialized versions of digital tape backup technology....
HDCam for example internally stores the video in a variant of Mpeg 4 (xvid) which is near lossless, and HDCam SR internally stores the video in a variant of h.264... (both at exceedingly high/near lossless bitrates though) Although the internal storage format is proprietary information so it's not possible to rip the raw bits from the tape... you have to play it on a compatible deck where it gets output over SDI connections in a raw lossless format.

So the practical difference between using digital files and tape is almost 100% workflow, not quality. The advantages to tape are the same as they are for using tape for generic digital backup... shelf-life, stability, and density. Shelf-life and stability are not so much better than bluray/dvd, and density doesn't really matter for consumers, so all the benefits of tape were useless at the consumer level.
Even at the pro level the only thing keeping tape going is legacy workflows and that it's still a slightly easier way of archiving.
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MarshalBanana



Joined: 31 Aug 2014
Posts: 2319
PostPosted: Fri Nov 24, 2017 2:58 pm Reply with quote
samuelp wrote:
One other thing to keep in mind that the question person might not have realized:
All modern tape formats are digital, not analogue. Digibeta and onward are pure digital formats internally, and are basically just very specialized versions of digital tape backup technology....
You can digital tapes, so is that like an actual tape, that has binary code stored on it. Is it like those old punch cards from the early days of computing.
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EricJ2



Joined: 01 Feb 2014
Posts: 3360
PostPosted: Fri Nov 24, 2017 3:07 pm Reply with quote
Quote:
Surely, you're not really wanting to go back to using tape to watch video, do you? As a format on which to enjoy a program, it's hard to even imagine going back to tape. Tape doesn't support menus or removable subtitles. They can take forever to shuttle around to find a scene you're looking for. They wear out, drop out, get eaten by dirty machines, and have to be rewound. A modestly strong magnet can erase them. They're heavy and expensive, and take up a lot of room on a shelf. They cost a lot of money to ship.


I was going to say "Remember when you saw your very first DVD?", and then realized...most probably wouldn't. Shocked That would be at least 1997, and anyone under the age of 20 would assume they had always been there.
(Causing other historical/sentimental misinterpretations, like that VHS had been "unfairly mistreated" by the new format the way vinyl-LP suffered from CD's, or that it was "ready for a comeback".)
Growing up on the 00's customer-weariness of new format wars, like Blu-vs-DVD, or "How to ruin Blu3D's sales", or "Did we even know what 4K was before we got excited about it?", it's hard to appreciate a technology that actually DID blow the previous one away with frustrated viewers in a fair fight.

I remember the birth of DVD, I remember every single one of the above-mentioned problems--who went out and bought a rewinder-machine, just so they wouldn't have to burn out their VCR Being Kind And Rewinding after every Blockbuster tape?--and I especially remember how the birth of DVD jumpstarted anime fandom:
Disks ended the Sub-Dub Wars by offering both, you could rent disks by mail, and digital files meant the old purple-cassette trading industry for fansubs was now suddenly a lot easier. You were actually afraid to play your Ghibli-movie fansub VHS's, since you knew that any tape's days were numbered to a certain number of playings, and panicked when the "gray hairs" of tracking-static started to show.
I didn't even notice it looked better until I dug out a forgotten old VHS tape from twenty years ago.

As for why tape is still used professionally, that's a fair question answered, even if most editing is now done digitally rather than on the moviolas.
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epicwizard



Joined: 03 Jul 2014
Posts: 419
Location: Ashburn, VA
PostPosted: Fri Nov 24, 2017 5:03 pm Reply with quote
Very interesting article. However, I feel like this part of Vandeilo's question wasn't fully answered:
Quote:
Why is it that such tapes aren't used for playback at the consumer level? I don't really see much of a reason why you couldn't just edit the video correctly for home playback (removing time of black screen and the like) and duplicate and mass produce tapes containing that information, which would be played back on VCR-like devices designed to read and interpret that data?

I suspect what Vandeilo was trying to ask there was why weren't high quality tapes (specifically the ones used for TV broadcasts) used for home media releases back in the day, while low quality VHS tapes, which were prone to showing really bad picture quality as well as producing weird buzzing sounds (unless if it's the VCR doing that and not the VHS tape?), were used for home media releases instead?

Also, Answerman,
Quote:
Tapes are still a bit more reliable than a hard drive (except in that they can easily have a tiny drop-out that's easy to miss -- whereas a bum hard drive will probably take out the entire file).

I'm a little bit confused at the part that I put in bold. What exactly do you mean by tapes can easily have "a tiny drop-out that's easy to miss"?
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Nilrem



Joined: 06 Dec 2003
Posts: 93
PostPosted: Fri Nov 24, 2017 6:19 pm Reply with quote
epicwizard from my understanding you can lose part of the picture on a frame due to damage to the magnetic tape, if the damage is small enough it might not be visible unless you are looking at every frame one at a time if it's an analogue tape, or the error correction on a digital tape couldn't catch it.

The likes of the BBC and ITV in the UK used to QC every new tape they received (at least in the early days) and grade it to avoid that sort of issue, then used to do something similar every time the tape was reused, I think they used to do a blanking run, then noise check/damage run - apparently a job the techs didn't like as it was boring but required full attention (I believe it was somewhat automated later).
To complicate things further because they were aware of the wear issue, tapes could be reused only a handful of times for something like mastering (or recording from camera), or national output and then might only be used to do regional output or daily news after a few uses as they were no longer up to scratch for jobs that required best quality.
To assist with this every tape had a form in it's case with it's history.

From reading and talking to some of the technical people on another forum, including those who used to maintain the machines it wasn't uncommon for the playback and recording heads to have a very finite lifespan even with dedicated trained personal running and maintaining them (some manufacturers gave a certificate if the heads lasted X hours before being replaced or refurbished as it was so rare).

Things improved over time, but that was the sort of situation the professionals faced, despite them taking very good care of the machines.

With regards to tape use at home, cost would be the answer I suspect.
Broadcast quality media and hardware is far more expensive than home quality.

[edit]
Edited to try and make it a bit more coherent, it's been a long day.


Last edited by Nilrem on Fri Nov 24, 2017 9:02 pm; edited 1 time in total
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fuuma_monou



Joined: 26 Dec 2005
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Location: Quezon City, Philippines
PostPosted: Fri Nov 24, 2017 8:52 pm Reply with quote
Nilrem wrote:
With regards to tape use at home, cost would be the answer I suspect.
Broadcast quality media and hardware is far more expensive than home quality.


Also, VCRs, with relatively low quality, were the subject of anti-piracy hysteria. I don't think the studios would want consumers to have access to the master tapes.
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Nilrem



Joined: 06 Dec 2003
Posts: 93
PostPosted: Fri Nov 24, 2017 9:06 pm Reply with quote
That's very true, although even just using the same style of tapes and recorders, without being quite master quality would probably have been a big improvement.

IIRC one of the compromises to get longer running times (and cheaper production) on home cassettes was a significantly thinner grade of the tape than on professional level equipment which meant it was more prone to stretching and other physical damage.
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Hiroki not Takuya



Joined: 17 Apr 2012
Posts: 752
PostPosted: Fri Nov 24, 2017 9:19 pm Reply with quote
epicwizard wrote:
... What exactly do you mean by tapes can easily have "a tiny drop-out that's easy to miss"?
As was pointed out, the tapes in question are digital in format while VHS was analog but both suffer from the pitfalls of magnetic material coated plastic tape passing over a pulse transformer head, if the material comes out of intimate (~few microns height) contact with the head, the magnetic pulses fail to magnetize the section of the tape above and you have a "dropout".

This can vary in intensity and duration depending on the electro-mechanical disturbance that caused it from making the "1's" magnetization less intense than they are supposed to be to be missing entirely. In the former case, the faulty area of data may be readable for a while but fade with time (as will happen to all the magnetic tape data eventually) if not cause outright errors and in the later case will cause an error or just make a spot of missing data.

However, these effects tend to be masked by Mpeg compression and other information coding schemes which are designed to detect errors and in some cases correct for them until they become too numerous. The software may not flag said errors unless the operator is looking specifically for such so they are "invisible". Video has so much data that is presented so quickly that as much as ~1% of the data could be corrupt (uncorrectable) before it becomes "visually noticeable". Mpeg is designed to be robust in that if a whole frame of the right type is corrupt, it will copy the last good frame over in it's place which again will not be "visually noticeable" and may not get flagged.

If the data is unencoded, a few milliseconds of missing or "errored" data will never be noticed. It takes massive, continuing errors to cause video decompression breakdown to interrupt the output stream.
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epicwizard



Joined: 03 Jul 2014
Posts: 419
Location: Ashburn, VA
PostPosted: Sat Nov 25, 2017 12:24 am Reply with quote
Thanks for the answers, Nilrem and Hiroki not Takuya!
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Sakagami Tomoyo



Joined: 06 Dec 2008
Posts: 610
Location: Melbourne, VIC, Australia
PostPosted: Sat Nov 25, 2017 1:12 am Reply with quote
EricJ2 wrote:
(Causing other historical/sentimental misinterpretations, like that VHS had been "unfairly mistreated" by the new format the way vinyl-LP suffered from CD's, or that it was "ready for a comeback".)

How was vinyl "unfairly mistreated" by CD? CD is straight up a better format, dubious claims of vinyl being a more accurate sound reproduction aside. ("Sounds better" is a slightly different thing; some of vinyl's flaws alter the sound in a way that sounds pleasant, which leads some people to think it sounds better and therefore is more accurate.)

EricJ2 wrote:
and I especially remember how the birth of DVD jumpstarted anime fandom:
Disks ended the Sub-Dub Wars by offering both, you could rent disks by mail, and digital files meant the old purple-cassette trading industry for fansubs was now suddenly a lot easier.

DVD certainly helped the anime fandom grow quickly, but it was already a sizable enough thing in the VHS era that it was possible to rent anime tapes in video libraries in regional Australia. (Not many, mind you, but any at all is still remarkable.)
But arguably it's less DVDs and more digital fansubs that really grew the anime fandom, and they have more to do with the rise of broadband internet than they do DVDs. Sure "offline file sharing" did happen and DVDs were used for that, but in the early days blank DVDs were expensive, and by the time prices came down enough, the internet was fast and cheap enough to still be a better option most of the time.
"Home DVD release as source for fansub, digital or otherwise" also wasn't really much of a thing. There were a handful in the tail end of the VHS era that were genlocked in the traditional manner but sourced from DVD rather than the usual Laserdisc. Digitally ripping DVDs was the best source for OVAs in the digital fansub era, but digital fansubs of TV anime were basically all captured from broadcast.
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CR85747



Joined: 13 Oct 2014
Posts: 65
PostPosted: Sat Nov 25, 2017 3:42 am Reply with quote
Is this a repeat column?
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Mohawk52



Joined: 16 Oct 2003
Posts: 8104
Location: England, UK
PostPosted: Sat Nov 25, 2017 5:31 am Reply with quote
The 2011 East Japan earthquake and tsunami was the final nail in coffin for broadcast tape as the factory that made most if not all of the kind used in broadcast and professional industries was literally scourered down to the concrete floor. It was what pushed the broadcast facility where I worked into developing digital media storage and retreaval systems for production, editing, and distribution with massive storage hard drive arrays, in short, going "tapeless".
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configspace



Joined: 16 Aug 2008
Posts: 3290
PostPosted: Sat Nov 25, 2017 10:05 am Reply with quote
Tapes were just a die hard old habit Japan held onto. It makes no sense to use tapes in modern times and even over a decade ago, when the format on the tape is digital and is edited and processed on a computer anyways. Discs are just plain better from all perspectives like random seeking and last longer. Even if hard drives have random reliability issues, modern drives are fast enough to make convenient backups of and one can always use checksums per file to ensure validity rather than human inspection. Whereas tapes undergo gradual degradation in storage and worsening degradation per usage and you can't store other custom metadata like checksums per episode in tape. For consumer physical deliverables of very large data, until the next BD format, I'd say solid-state media like SD cards or usb flash drives would be better.
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Macross_1



Joined: 25 Nov 2017
Posts: 4
PostPosted: Sat Nov 25, 2017 6:45 pm Reply with quote
Why not use M-DISC (Millennial Disc). They are non organic based and will last approximately a 1000 years. They basically work like a record player in that it etches into the disk. The only thing to fear would be fire or snapping one in half, for most part anyways. I back up a lot of my stuff onto them. They are not cheap but worth it for precious data protection.

On a side note,

As for VHS/BATAMAX I do miss it sometimes. I wish I hadn't broke my Hitachi Ultravision VHS player. Skipping commercials long before digital data. I still have and use my JVC from '82 or something like like. Works like the day it was built. Solid Steel construction. I still have my full run of Robotech as well, every tape. To me it's like my comic books, sure digital makes it super easy to store, read and access any part of them but there is nothing like the smell of an old comic to bring back good memories. This is something the millennial will never truly understand. We truly are in the "disposable" age. How many digital pictures have you made into hard copy lately? Ahhh nostalgia Razz
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