Stutter with TBC on

[agisthos]

The JVC TBC/NR feature is great and has stabilized and fixed unwatchable VHS home video.

But in my very brief learning doing this I have already come across a commercial production video (PAL) that has serious stutter at dozens of random points throughout when TBC is enabled. This stutter is NOT there when captured normally with TBC OFF.

See both 15sec examples...
https://mega.nz/folder/HN9iUZiQ#-n9WWmPwAc3Iw19w95LcBA

So its obvious that TBC is causing this. Can this stutter or shaking be removed when doing conversion/restoration?
Please don't tell me the JVC 'Video Stabilization' setting will fix this, as the HR7600 I purchased does not have that feature *slaps head*

You may say why not just capture with TBC off? Well when its working the TBC setting gives a more stable and better picture, and it also fixes the bend/warp that is at the top third of the picture. Maybe the VCR can be adjusted/aligned to get rid of that bend (tape back tension?) but I have never adjusted a VCR yet.

[orsetto]

Unfortunately these JVC TBC/DNR circuits do indeed go haywire when confronted with the occasional weird tape (and if you have really bad luck, more than a few tapes). The line TBC+DNR generally helps correct visual issues quite nicely, but every now and then it exaggerates underlying flaws into more visible jitter/jump problems (typically triggered by second or third generation dupe tapes and certain original camcorder tapes). When this occurs, all you can do to stop the jumping is turn off the TBC/DNR, which makes these premium VCRs no better (and sometimes worse) players than some less-expensive decks for some types of tapes.

Those of us with a great many tapes to transfer end up spending money on a variety of different VCRs and workarounds to cope with different contingencies. When you encounter the "JVC TBC causes jumpy jitters" issue, there are other methods you can try at varying costs. The easiest (but most hideously expensive) alternative is switching to the Panasonic AG1980 VCR. It has similar TBC/DNR correction performance to the JVC system but is implemented in a different manner: the Panasonic circuit operation is just different enough that it often successfully works on tapes that jitter and jump under the JVC circuit design. The Panasonic has a slightly different look to its TBC/DNR: some people prefer the JVC, some prefer the Panasonic, but realistically we have to use whichever one allows capturing the tape best despite preference.

If the Panasonic AG1980 is out of budget or also shows jumpiness like JVC, you can try passing the signal of your JVC (or any other VCR) thru the inputs and outputs of a Panasonic ES10 or ES15 dvd recorder. These old dvd recorders have their own proprietary signal correction circuits that can repair problems the VCR internal TBC/DNR mishandles. You connect the outputs of your VCR to the inputs of the recorder, and outputs of the recorder to inputs of your capture device. There are nuances involved, if interested search for threads with the terms "Panasonic DVD recorder capture passthru". These recorders are relatively inexpensive compared to other options, esp if the un-needed dvd drive is defective.

[agisthos]

Right, I had read that the JVC TBC can have stutter, so what I am seeing here is that exact thing? Because I am so new to this, this is what I am trying to determine, that it's not a fault in the player itself.
This is only the 4th tape I am playing with, and a commercial tape, so perhaps this issue will come up more than infrequently.

Rather than putting it through a ES10/15, will one of the external TBC boxes fix this you think? I guess we do not know until it's tried.

btw Orsetto I really got a kick out of reading your posts from 2012, about your history with VHS.

[orsetto]

External TBC does not usually fix this: the external TBC is a different "kind" of TBC from the one built into VCRs. The jumping is a bad interaction between a certain kind of problematic tape and the type of TBC built into these VCRs. Its more common with JVC VCRs and the Mitsubishi DVHS than with the Panasonic 1980, but I've experienced it a few times with the 1980 as well. The only reliable workaround is to turn off the TBC (JVCs with the stabilizer feature automatically disable TBC when you use the stabilizer).

The Panasonic ES10/ES15 workaround relies on the circuit in the recorder to repair the signal instead of the TBC/DNR in the VCR (although you can try both simultaneously as well). These dvd recorders have a circuit somewhat similar to the VCR TBC/DNR: it isn't as clean or nice at fixing noise or color bleeding, but its much beefier at repairing judders, tearing and flagging. This is different from a dedicated external TBC box, which only repairs "invisible" signal flaws that cause timing errors, dropped frames and audio lipsync drift.

A JVC vcr with TBC/DNR cures a lot of ills, but occasionally you'll hit a tape that needs another or different tool. You've said this is a "commercial tape" - if so, it may be protected. Protected tapes can interact weirdly with VCR TBC, they typically do require an external TBC to properly remove the protection interference. Other commercial tapes that aren't protected can have other mastering issues that trigger the vcr TBC to judder.

[agisthos]

Is there any way to adjust the internal of the VCR to straighten the slight vertical warp/curve at the top of the picture when TBC is off? I read this has something to do with tape tension. My cheapie Panasonic VCR from early 00's can output a straight picture, but its nowhere near as good quality as the HR7600.

[orsetto]

Is there any way to adjust the internal of the VCR to straighten the slight vertical warp/curve at the top of the picture when TBC is off?

In theory yes, but it isn't worth the risk of damaging the VCR with a misalignment. Some here report doing this with inexpensive "disposable" VCRs like your Panasonic, to help in playing some very off-spec tapes. But its inadvisable to do on an expensive JVC TBC/DNR model like the 7600, esp if the 7600 seems to work just fine for you otherwise with most typical tapes.

Repeating what I said earlier: if the "commercial tape" giving you trouble is a Hollywood movie tape, chances are its protected with a badly-applied protection signal. Poorly applied protection can cause warp/curve at top of frame with JVC TBC turned off, and trigger judder if the JVC TBC is turned on to get rid of the warp/curve. A known issue that happens when JVC and Mitsubishi VCRs play certain difficult tapes with their TBC/DNR active. Thats why the TBC/DNR has an "off" button: most tapes benefit from it, but a few annoying ones don't.

[agisthos]

OK thanks for all this. I do however find the warp/curl is there with all tapes when TBC is off, even home recorded, that's why I was researching how to adjust the VCR for this. But the HR7600 I got is immaculate and looks to be almost unused and working in all other respects, so perhaps best not to mess with it.

Just found a mint Panasonic ES10 (is that better than the ES15?) here in Australia for about 170 USD.

In all the reading up I have done about these external frame sync devices, I am surprised that newer capture cards do not do this as well in hardware during capture, as the processing headroom on newer low power chips would be 20x that as found on those old boxes from the 90's.

[orsetto]

Strangely enough, the ES10 is the most powerful device ever made for correcting VHS warps, jumps, distortion and whatnot: even multi-thousand-dollar pro hardware can't equal what it does. The ES15 is also good but not quite that level, the ES20 slightly less than the ES15. Any of these will simulate the effect of the TBC in a JVC vcr, while adding additional capability to repair defects the JVC cannot handle by itself. The difference lies in the VCR TBC/DNR having the advantage of direct coupling to the video heads, which gives you nicer clearer colors than you can get from the Panasonic passthru alternative. Different strokes for different tapes: use whatever compromise works best.

The dirty little stupid secret paradox of capture cards and USB sticks is few to none of them were actually designed/intended with VHS capture in mind: they were engineered with the fantasy premise that their primary use would be capturing super clean stable video from a TV tuner. Probably because VHS is such a terrible unstable source that guaranteeing perfect VHS capture would require a much larger more expensive device incorporating assorted stabilization circuits, which would make the things less appealing to the typical Amazon shopper. Hence all the additional nonsense we have to put up with like exotic VCRs, Panasonic ES10s, DataVideo TBCs, etc.

If your 7600 is giving you a warping flagging frame top on all tapes with its TBC turned off, thats unusual and a red flag that either your tapes or this 7600 are seriously out of spec. Warping/curving typically happens only with some duped tapes, some commercial tapes, and some types of original camcorder tape. It should not be happening with every single tape you load in your 7600: if thats the case, the TBC judder might be induced by the 7600 itself adding too many playback errors that overload its TBC. In that case your 7600 would need to be serviced by a technician with proper tools: I would be uneasy attempting DIY alignment on this model. The 7600 incorporates the problematic JVC Dynamic Drum feature, which may or may not be contributing to your warping symptoms.

Have you checked these tapes in other VCRs? If you don't get the warping/flagging with the same tapes in other non-TBC VCRs, I would suspect your 7600 needs an overhaul. Despite their potential for high performance, this generation of JVCs can be irritatingly flaky ("mint" appearance often conceals a malfunctioning deck: I've had a few that were defective out of the box bought brand new at the time they were current). Buying a premium second-hand VCR today can be very tricky: many need servicing.

[agisthos]

I did come across those vids of flagging/waving at the top of the picture. Nothing like that, its just the picture vertically curves slightly leftwards near the top. Its nothing too serious but noticeable the us OCD guys.

The problem is finding a VCR tech in my city of 1 million. Those guys are all retired now. I cannot even get my audiophile amp recapped right now, as both techs I used to use have retired.

The 7600EK/EU does not have the dynamic drum (or it has it but its not listed as a feature on the unit). Some other PAL 7600 series models do, like the 7600AM.

[lordsmurf]

The ES15 is also good but not quite that level,

ES15 is almost the same as ES10. ES10 slightly stronger.

the ES20 slightly less

No. The ES20 is entirely different, almost inert, does nothing.

nicer clearer colors than you can get from the Panasonic passthru alternative.

The ES10/15 has all sorts of side effects, and I've discussed those many times at length at multiple sites. So only use it when the net effect is better video. It's not advised as a general always-use TBC (but some try, and make it a poor man's TBC, to varying effectiveness).

The dirty little stupid secret paradox of capture cards and USB sticks is few to none of them were actually designed/intended with VHS capture in mind: they were engineered with the fantasy premise that their primary use would be capturing super clean stable video from a TV tuner.

Yep. Although many folks did use it for the tuner, early one, not VHS tapes. That came later.

Probably because VHS is such a terrible unstable source that guaranteeing perfect VHS capture would require a much larger more expensive device incorporating assorted stabilization circuits, which would make the things less appealing to the typical Amazon shopper. Hence all the additional nonsense we have to put up with like exotic VCRs, Panasonic ES10s, DataVideo TBCs, etc.

Yep.

If your 7600 is giving you a warping flagging frame top on all tapes with its TBC turned off, thats unusual and a red flag that either your tapes or this 7600 are seriously out of spec.

Misaligned, needs realignment. Can be easy, can be hard. This very minute, I'm screwing around with a stubborn deck. It's frustrating.

I did come across those vids of flagging/waving at the top of the picture. Nothing like that, its just the picture vertically curves slightly leftwards near the top.

"Serious" or not, that's what it is -- tearing. ES10/15 is the workaround for those exact bad tapes. Disable JVC TBC on those, use ES10/15, and done.

Its nothing too serious but noticeable the us OCD guys.

Everybody sees those obvious errors. Most don't like it, even if they say nothing.

[orsetto]

The problem is finding a VCR tech in my city of 1 million. Those guys are all retired now. I cannot even get my audiophile amp recapped right now, as both techs I used to use have retired.

Yeah, I sympathize, its the same here in the states: the repair situation has gotten pretty dire as more and more people become interested in "obsolete" tech like VCRs, vintage stereo components, and film cameras. Most of the remaining qualified techs were set to retire ten years ago, then got flooded with so much new business they couldn't give up the income. A large percentage are in their 70s or even 80s now, with insanely long wait lists and no apprentices in the wings to replace them at the workbench. About five-ten years from now we're gonna be in a world of pain when our turntables, amps, tape decks, VCRs, Hasselblads and Leicas need repair: all we'll have to fall back on is DIY guided by dodgy youTube tutorials. I've slowly stocked up with as many functional backups as I can afford: the day the last item breaks I'll go back to passing the time reading books in a comfy chair.