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  #21  
10-14-2021, 01:58 AM
latreche34 latreche34 is offline
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Black tape doesn't necessarily mean metal, Metal is a very special formulation and the playback/recording machine has to have a special tape equalization in terms of recording and playback currents, erasure current, bias frequency... etc. You can't use the same VCR to playback normal tapes and metal tapes without having to switch from metal to normal and vise versa just like in an audio tape recorder. Besides metal formulation wouldn't work for Hi-Fi depth recording and linear audio anyway. Wondered why ED Beta VCR's have a switch for Super Beta and ED beta? It's for that purpose.

Even metal formulations are not created equal, tape stock is not interchangeable across a lot of consumer and pro formats. I learned that by experimenting with these types of tape formulations and put them in different cassettes. For instance I tried VXA data tapes in a D8 camcorder and I couldn't get a useful recording, Even in a Hi8 camcorder I got chroma rainbows and a lot of luma noise. I put a digital Betacam tape into D-VHS and S-VHS cassette shells and I couldn't get a digital recording, in S-VHS mode the recording was very messy, The same tape produced noisy recordings in ED Beta mode. So tape equalization is very important.

https://www.youtube.com/@Capturing-Memories/videos
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  #22  
10-14-2021, 02:31 AM
RobustReviews RobustReviews is offline
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Quote:
Originally Posted by latreche34 View Post
Black tape doesn't necessarily mean metal, Metal is a very special formulation and the playback/recording machine has to have a special tape equalization in terms of recording and playback currents, erasure current, bias frequency... etc. You can't use the same VCR to playback normal tapes and metal tapes without having to switch from metal to normal and vise versa just like in an audio tape recorder. Besides metal formulation wouldn't work for Hi-Fi depth recording and linear audio anyway. Wondered why ED Beta VCR's have a switch for Super Beta and ED beta? It's for that purpose.

Even metal formulations are not created equal, tape stock is not interchangeable across a lot of consumer and pro formats. I learned that by experimenting with these types of tape formulations and put them in different cassettes. For instance I tried VXA data tapes in a D8 camcorder and I couldn't get a useful recording, Even in a Hi8 camcorder I got chroma rainbows and a lot of luma noise. I put a digital Betacam tape into D-VHS and S-VHS cassette shells and I couldn't get a digital recording, in S-VHS mode the recording was very messy, The same tape produced noisy recordings in ED Beta mode. So tape equalization is very important.
**Nods sagely**

Tape stock is a subject close to my heart, it's a very complicated topic and you're dead right here. Good point on ED Beta, this totally changes the bias and level of the recording - this is why it's not always a "good, better, best" paradigm between different tape formulations, they each have a special role and different requirements. cf. Betacam and BetacamSP.

I've not thought about depth-multiplexing though, that's an interesting consideration, that doesn't work in PAL territories as Betamax HiFi is depth-multiplexed in PAL regions akin to VHS, Betamax PAL and Betamax NTSC are quite different beasts whereas VHS is a much more uniform system.

The Korea thing wanders in to SKC (or a Saehan shell), but this isn't a forensic examination of tapes or climates, but I'm reasonably confident in my remarks on this, but ultimately it's just conjecture.

What I can say with near certainty is that BASF tape from the early 1980s is likely to be heavily chromed, the UK market example before me has all the hallmarks of a heavily chromed tape stock, chrome tape is known to degrade badly in certain climates and would delaminate or shed after time.

Another thing I might experiment with in downtime is audio, my hypothesis being that chrome formulation VHS cassettes have noticeably less noisy linear audio compared to usual doped ferric forumations?
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  #23  
10-14-2021, 07:49 AM
NJRoadfan NJRoadfan is offline
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Looking at Ray's Betamax site, BASF appears to have made chrome Betamax blanks: http://www.betainfoguide.net/basf.jpg
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  #24  
12-01-2021, 04:57 AM
RobustReviews RobustReviews is offline
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Just to follow up, I currently have a stack of BASF EU market VHS tapes here.

They all absolutely 'stink' of wax crayons, so much so that you notice it as soon as you open the box.

The tape stock looks identical and smells exactly the same as V2000 tape stock.
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  #25  
12-15-2021, 02:55 PM
Niknik Niknik is offline
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Magnetic retentivity: The ability to retain the generated magnetization in a magnetic material when the magnetizing force is removed is called the magnetic retentivity of that material. ... It is the capacity of a substance to retain magnetism after a magnetizing force is removed.

There is no such thing as perfect retentivity. ALL materials will eventually lose their magnetic charge.

Short answer to your question: Yes, magnetic video recordings will eventually fade away in storage. The question as to how long before it is unusable is almost entirely dependent on the materials used in the manufacture of the tape. I say "almost" as the subsequent storage of the tape will have some impact, but I find that since most tapes aren't stored in a hot attic, and are instead kept in a climate controlled home or business, that is rarely an issue.

I have some high quality VHS tapes that I recorded back in the late 80's that still look almost as good as new and I have some lower quality tapes (purchased videos) from just over 20 years ago that have suffered significant loss. Fortunately I had the foresight to use nothing but high quality tapes for my own personal home video recordings back in the 80's and early 90's. Having remastered and archived them again (for the 3rd time now) within the last year or so (using a JVC D-VHS deck, DVDO processor, and Colossus II Capture Card) I noticed that they still hold up, but I wouldn't wait too long to convert yours to digital. Every tick of the clock brings them closer to death.

Last edited by Niknik; 12-15-2021 at 03:12 PM.
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  #26  
12-15-2021, 03:46 PM
latreche34 latreche34 is offline
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Quote:
Originally Posted by RobustReviews View Post
Another thing I might experiment with in downtime is audio, my hypothesis being that chrome formulation VHS cassettes have noticeably less noisy linear audio compared to usual doped ferric forumations?
I've always wondered if VHS tape works for audio recording in a 1/2 R2R machine at 15 ips, I don't have 1/2 R2R deck to test with, I suppose I could try it on my Sony R2R deck that can only go up to 7.5 ips if I find a way to slice the tape in half to make 1/4 inch tape. I know for a fact that people tried it for compact audio cassettes and the results were mediocre, 15 ips might work.
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  #27  
12-15-2021, 08:22 PM
dpalomaki dpalomaki is offline
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A T-120 VHS tape has about 246 m (roughly 800 feet of tape) or about 1600 feet split.
At 15 ips that is about 21 minutes of recording.

I suspect recording bias setting for video tape used as audio would have to be changed, as might equalization curves. And you could enjoy all the blessings of analog audio tape recording.

Below is a listing for a film splitter. Wonder if they would make a version that can split 1/2" video tape (12.7mm) to 1/2"? (I have not used it so I have no idea as to whether or not it would work.)
https://www.etsy.com/listing/266829907/film-slitter-to-cut-any-roll-film

While precise width is not very critical for film it can be for audio tape due to the narrow track widths once you go below full track heads on 1/4" tape. Width variations can cause variation is track alignment on the heads.
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  #28  
12-16-2021, 10:54 AM
RobustReviews RobustReviews is offline
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Videotape does make especially poor audio recording tape, I've never researched the precise reason but some especially low quality (the derided Type 0) tapes often used slit video tape. Whether metal or chomed videotape stock works I don't know, it would be an interesting experiment. We have a 1/2" multitrack machine somewhere in the storeroom (I think) so I might have a fiddle one day.

Definitely, the bias and curves as dpalomaki points out would need recalibrating.
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  #29  
12-16-2021, 03:24 PM
timtape timtape is offline
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We'd need to specify the ways in which the audio quality would be inferior using VCR tape on say a 7.5/15ips open reel analog audio recorder.

A fundamental difference between the two is the thickness of the tape. A typical VHS tape has a thinner plastic base tape and perhaps a thinner magnetic coating, for overall a much thinner tape than Standard open reel tape. The former increases print through (pre and post echoes especially over time) and the physical robustness of the tape such as resistance to stretching and creasing. The thickness of the magnetic layer affects the low frequency response because the lows penetrate deeper into the layer than the highs.

These differences were known once the different length open reel audio tapes such as Standard Play, Long Play, Double Play, Triple Play etc came onto the market some time in the 50's or 60's.
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  #30  
12-16-2021, 03:53 PM
latreche34 latreche34 is offline
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Yes the major concern is the magnetic layer thickness, Thin layer gets saturated quickly by the magnetic head but if the transport speed increased it may prevent the tape from being exposed for too long to the magnetic field, That with some equalization tweaking it should probably give decent results. I know for a fact Betacam SP analog tracks are recorded on a similar tape but with higher speed 4 ips, In most cases Betacam employs a Dolby C NR system but I listened to some tapes without NR and they sounded pretty darn good, So with 7.5 or 15 ips I believe Dolby NR is no longer needed.

https://www.youtube.com/@Capturing-Memories/videos
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  #31  
12-16-2021, 04:32 PM
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Quote:
Originally Posted by latreche34 View Post
Yes the major concern is the magnetic layer thickness, Thin layer gets saturated quickly by the magnetic head but if the transport speed increased it may prevent the tape from being exposed for too long to the magnetic field, That with some equalization tweaking it should probably give decent results. I know for a fact Betacam SP analog tracks are recorded on a similar tape but with higher speed 4 ips, In most cases Betacam employs a Dolby C NR system but I listened to some tapes without NR and they sounded pretty darn good, So with 7.5 or 15 ips I believe Dolby NR is no longer needed.
Film thickness and coercivity are quite different topics, you're broadly right; but with the broadest of brushstrokes.

Betacam SP sound is very good (even on the relatively slower PAL speed) and was more than good enough for broadcast television even in markets like the UK where we switched to digital* stereo for television broadcasts in late 80s with most but the cheapest sets decoding it by the mid-90s. Betacam SP was more than good enough for this and our system (various others were used across Europe and Japan I believe) were near CD quality so would show up defects. However if you closely monitor Betacam SP it still does 'hiss' and whilst through obvious format improvements and companding it does eliminate most tape noise, it's not absent. It's far better than linear VHS/Betamax/V2000 though and is arguably more pleasant sounding than PCM or MPEG audio streams from the 1990s.

One of my businesses did an awful lot of experimentation with audio on various videotape formats so I can probably dig out some old reports if you want to see the numbers that we found. Betacam SP was a high-quality system though, I'm not denigrating it, but the hiss is still intrusive with focused listening.





*NICAM or 'Near Instantaneous Companded Audio Multiplex' - it's a slippery topic.
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  #32  
12-16-2021, 05:13 PM
timtape timtape is offline
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The main problem I heard with Betacam Dolby C audio was Dolby mistracking artifacts, often audible on news footage possibly due to misalignments between the camera deck and the studio playback deck, then perhaps compounded by the tracking errors being baked into copies. Companding NR came at a price: higher standards of maintenance (including cleanliness) and alignment. Of course Betacam SP hissed but compared to the mistracking problems it was minor.
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  #33  
12-28-2021, 07:20 PM
timtape timtape is offline
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Quote:
Originally Posted by latreche34 View Post
No, S-VHS is not metal and so does D-VHS because it's based on S-VHS formulation, I recorded D-VHS HD MPEG-2 @ 25MB/s on a S-VHS tape by just adding the extra hole required for D-VHS recognition, not a single glitch. Hi8 and D8 are metal because they record an equivalent S-VHS signal or better on half the size tape, high density formulation was needed.
I found the reference to S-VHS tape being a Metal formulation. It is in the IASA TC 06 C Standards paper. Its reference is Beeching 2001 p.56.

It's barely mentioned but it does mention the Metal formulation in passing:

"Older S-VHS machines will switch into normal VHS recording mode when detecting
an oxide rather than metal tape. However, JVC later produced the SVHS-ET system
(Beeching: 2001, p. 56), which allowed certain machines to make S-VHS recordings on
standard tapes, further complicating playback for archivists."

I'm trying to locate the Beeching paper.
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  #34  
12-28-2021, 08:51 PM
dpalomaki dpalomaki is offline
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Quote:
...Older S-VHS machines will switch into normal VHS recording mode when detecting
an oxide rather than metal tape....
Hmmm. Conventional wisdom was that the machines detected the hole in the cassette that denoted S-VHS. If based on detecting the tape formulation then making the hole in the cassette would NOT have worked. And detection would likely have required a record/play cycle to verify tape type every time it was inserted.

S-VHS can be recognized on playback by the frequency of the luma carrier recorded on tape.

In the late 1980s or early 1990s one of the consumer/prosumer oriented audio/video magazines did a fairly technical review of video tape comparing around 5 or 6 characteristics for several popular brands. But sadly I do not recall which mag it was.
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  #35  
12-28-2021, 09:33 PM
timtape timtape is offline
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Quote:
Originally Posted by dpalomaki View Post
Hmmm. Conventional wisdom was that the machines detected the hole in the cassette that denoted S-VHS.
The hole in the S-VHS tape and the sensor for it in S-VHS decks are more than "conventional wisdom". They are facts. In front of me is a Sony S-VHS cassette with the extra hole. Next to me is a Panasonic S-VHS recorder with the pin to sense such a hole, indicating a cassette containing a tape optimised for S-VHS recording.

Quote:
Originally Posted by dpalomaki View Post
If based on detecting the tape formulation then making the hole in the cassette would NOT have worked. And detection would likely have required a record/play cycle to verify tape type every time it was inserted.
A similar tape identification system was used extensively on later compact audio cassettes. The record lock out tab feature was extended to extra holes in the case for detection of Cr02 or Metal cassette tapes, automatically adjusting the deck's record bias, record EQ and playback EQ, but only on decks equipped with the sensors. Of course it was an indirect system and relied on the hole matching the tape, which it would from the factory unless somebody later opened the case and swapped tapes!

Quote:
Originally Posted by dpalomaki View Post
S-VHS can be recognized on playback by the frequency of the luma carrier recorded on tape.
Yes the frequency would denote that it was recorded in a S-VHS recorder in S-VHS recording mode. It wouldnt necessarily indicate the tape type. The higher frequency luma carrier could have been recorded onto a VHS tape and produced a picture, just as it is possible to record traditional audio onto a Type I cassette with bias and EQ settings not matched to the tape. We get a result but it's not ideal. Just because a result is possible on a tape doesnt mean it is the best result possible for that tape.

The Beeching text referred to is:

"Video and Camcorder servicing and technology, Steve Beeching, Newnes, 2001"

I see there is a copy in our state reference library.

Last edited by timtape; 12-28-2021 at 09:50 PM.
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