TBC Help - Worse results with than without?!?

[oswaldt]

Looking for some help or actually an explanation of why I would be getting worse results on certain tapes using a TBC versus without. The tapes are 15-20 years old and when run through the TBC (AVT8710) I get a "hockey stick" effect at the top. I grabbed a picture from another post that exactly illustrates the problem.

My setup is as follows Panasonic AG-3200 VCR -> AVT8710 -> Canopus/Grass Valley ADVC-300 -> MacPro via Firewire. With the AVT8710 I get a pronounced effect (probably the top 1/5 is "bent over"). With it removed I only get a few lines at the top "bent over". I also have another tape that I cannot use the 8710 on. It doesn't seem to be able to track the picture (horizontal and vertical hold - remeber those - get all fouled up). Without the TBC, the tape plays fine...

Any ideas?

(Long time lurker, first time poster)

[oswaldt]

Having trouble getting the image attached...

[lordsmurf]

Panasonic ES10 would clear that right up. It needs a special kind of sync filter run over it.

[Alan69]

A timebase corrector is good at fixing the specific problems it's good at. Different problems or things outside of its range simply won't get fixed.

If you are safe enough around electronics to not touch power supplies and get yourself electrocuted and this tape is important enough, there should be an easy fix. Get a 'don't care' VCR that plays this tape where it looks about the same. Take off the top cover, you should see two guide posts, one on either side of the round video head drum. While playing this tape, use a screwdriver to slightly screw the left guide post a little up and then a little down until you get this to play correctly. The left post affects the top and the right post affects the bottom, this should require a slight turning of the left post to fix.

While recording the tape runs across the video drum and the video heads record their stripes at an angle. One VCR is different from the next, even though there is supposed to be an exact standard, VCRs are often aligned a little off from one to the next or become so over time. Looks like this tape is coming into the drum at a slightly different angle than how it was recorded, adjusting that left post slightly should correct for it.

Don't do this to your good VCR, without a reference tape and equipment you'll never get it aligned exactly as it was, so you'll have problems with other tapes that you didn't before. Get a $25 used VCR that comes close to playing this tape like that, and tweak it instead.

Since it looks like an actual physical misalignment of the tape, the video frame is really being read off the tape like that, very far off. A TBC can only do so much electronically, if it's actually being fed that's very far out it can be difficult to work with.

There are other problems that can mimic this, so this isn't 100% guaranteed to fix it. But 90% or more of the time this will be the problem on a tape looking like this, so likely just doing this will let you make a good copy.

[oswaldt]

That makes sense. I am electronically inclined but am probably not going to mess around with VCR guts for these tapes. I'll just capture without the TBC and crop out the "bent over" part. Good information for future use though, I'm going to have to pick up a cheapo VCR to experiment with...

Any ideas on why the TBC created so much trouble with the other tape (looks like horizontal and vertical hold were totally off with TBC on, steady picture with TBC off)?

[lordsmurf]

I don't think it has anything to do with the VCR not caring. It's a sync issue, and digital devices are sticklers for proper sync.

[SmokieStover]

That makes sense. I am electronically inclined but am probably not going to mess around with VCR guts for these tapes. I'll just capture without the TBC and crop out the "bent over" part.

Burn to DVD first. Looks like the bent vertical lines fall in the overscan area.

[deuce8pro]

Panasonic ES10 would clear that right up. It needs a special kind of sync filter run over it.

I've found this to be untrue.
The Panasonic ES10 doesnt correct the tearing issue in pass through.

[lordsmurf]

Panasonic ES10 would clear that right up. It needs a special kind of sync filter run over it.

I've found this to be untrue.The Panasonic ES10 doesnt correct the tearing issue in pass through.

I've never seen a tape that could not be repaired with this method, unless it was a multi-generational copy, and the error was deeply embedded into the image, not just an error present in the signal. Even a few generations down, the errors can be fixed. It works well with more than tearing, it can correct in-frame wavy lines and an error that I can only describe as a still puddle when a little pebble is thrown into it. That watery look on screen. The ES10 fixes it. I have a test clip I need to upload sometime.

[vhelp]

Evening guys.

You know.. i've seen this problem in the past. Now, I know that this same problem has been
discussed countless of times before, here. But it still persists, I guess. Anyway.

My commercial vhs tape of the movie, "Jeepers Creepers" would do this when my setup was
for capturing this movie to my HDD. My equipment (at the time) was the following:

VCR: JVC S-VHS HR-S3910U
Capture card: (pci) DC10Plus
Capture card: (agp) ATI Rage Fury Pro
Capture cad: (firewire) Canopus ADVC-100
TBC: tbc-100
Connectors: composite (RCA) and s-video

I should point out that during that time period with this same 'flagging' issue, (the op refered to
it as a 'hockey stick' ) I was testing many other capture cards. The two listed above were
my primary cards at the time of the last tests. This was a couple of years ago, and at that
time period, we carried on with several discussions on VCR everything. It was fun time, back
then. Anyway.

In my experience with this 'flagging' on my vhs movie, 'Jeepers Creepers' and the above equip
setup, I could not get rid of it. It was a stubbern bastard. And, when incorporating my TBC
into the mix, it actually made the 'flagging' worse!! I recall mentioning that in prev discussions
over here. But, I did get rid of this issue (with this particular tape) by using my ADVC-100.

What exactly causes it is not quite clear.. but it was determined that this is a product of the
vhs tape's macrovision signal embeded in the videos recording to tape. And, when the vcr
and/or external "capture" (or, recording) equipment comes into contact with this jamming signal,
(depending on the capture/recording equipments macrovision receptor and rules) the video
output's quality would be affected in some way or another. Some equipment would exhibit
the Color fade; or Flagging; or Jittery video; ect. etc. But the results varied form equipment
to equpment, etc.., and depending on the equipment, it could be: good; fair/poor; or bad;

Now, when something like this happens, you have to take a step back to Anlyize and Review
what is in front of you.. your equipment; age of each; source tape; condition of it; your equip.
built-in macrovsion circuitry ready-ness; etc etc etc. You have to realize what you have in
front of you. Are you looking at a pre-record of an event that you recorded many years ago,
or are you using someone else's recorded tape that could have been a commercial tape that
was recorded (or dubbed) by another vcr. These are some of the things that are part of the
missing puzzle, and we are trying to piece them back together, piece by piece. Know what I
mean ? Anyway.. as I was saying..

If you have something that is exhiting the signs of 'flagging', then its prob either of two conditions.
macrovision; or poorly recorded/aged/equipment/tape source. But as a sub-division, there is
also (when utilizing the computer equipment) the capture card driver support. Most ATI products
are servents of macrovision, and contain inside their drivers the support for macrovision rules.
That means that whenever a video source sync signal (or whatever it is called that contain the
macrovision jamming signal) is sensed, the conditions or rules set up by macrovision are applied
and the jamming signals results are produced at the capture software's video preview window.
And, the results will vary from card maker to card maker because of this. Then there are the
other sub-division to this nonsense, where the capture card or video card has hardware built-in
that serve macrovision in real time. Hay, don't forget.. there is the new servent, DRM. Be on
the lookout for anything with 'drm' embeded or '.ms' at the end, though this is mostly being
used in HD type sources -- the future is being run by Dumb Retarded Morans

If it is macrovision, then you have to debug which vcr and capture card or recording equipment
would produce the least 'flagging' if any. As I said earlier, my ADVC-100 completely removed
(not that it removed it, but because of its built-in electroncis responsible for receiving and
outputing the video signal) the 'flagging' from the video output as it was received by my pc's
capture card, (the advc-100, that is) and my capture software's preview window.

Beside my advc-100, about the best way you can get rid of this is by using an old generation
capture card, like the old ATI TV Wonder VE or other vfw generic. The Hauppauge WinTV-GO
is another good card that did not serve the beast, macrovision -- mileage will vary.

lordsmurf, you could try the 'jeepers creepers' vhs tape. It has this exact issue of
the flagging, curling, whatever you want to call it, I'm game My advc-100 cures this.
If what you say about the Panasonic ES10 curing this is true, than the two equipment have a
similar feature built-in. But finding out EXACTLY What is this and What is causing it is also
very important.. at least we can suggest the proper tools to remove or cure or reduce it.

-vhelp 4475

:P *~*!*~*!~* HaPpY HoLiDaYs *~*!*~*!~*

[davideck]

Looking for some help or actually an explanation of why I would be getting worse results on certain tapes using a TBC versus without. ... With the AVT8710 I get a pronounced effect (probably the top 1/5 is "bent over"). With it removed I only get a few lines at the top "bent over". I also have another tape that I cannot use the 8710 on. It doesn't seem to be able to track the picture (horizontal and vertical hold - remeber those - get all fouled up). Without the TBC, the tape plays fine...

Any ideas?

You are correct. The AVT8710 cannot track the error in the picture. It reacts too slowly to rapid timebase deviations. This looks to be a large amplitude and rather high frequency timebase error that is beyond the correction capability of many TBC systems.

The ability to reduce, eliminate, or even exacerbate this error depends upon the sampling clock derived for the A/D conversion in the TBC or Capture device. If the system can track the error, then it can remove it. If not, then it ends up looking the same or even worse.

Yours is a more extreme case of the kind of timebase error that was documented in this thread;
https://forum.videohelp.com/topic289311-60.html#1450793

[vhelp]

Ahh, davideck, nice of you to recapture an old discussion from the day

Actaully, I did have an observational point to question over on that thread. I should prob
bring up my thoughts over on that thread though, even if its a little aged now.

And actually, I would like another test to be considered because it is based on one of the
older posts pictorial demo'ed in one of the responses and relates to a thought I had then,
(but forgotten) and now, because I remember it now

I'll post there, but mainly in hopes that the test could be done. You see, I don't think
that I can run it, but I think that one of the other members can. Perhaps some of the
readers on this thread can.

So, let me try and compose my thoughts as best I can remember them then, and now,
and see what I can throw up on that topic, over there.

So until then..

-vhelp 4478

:P *~*!*~*!~* HaPpY HoLiDaYs *~*!*~*!~*

[lordsmurf]

I once had a Young Adventures of Indiana Jones retail tape with Macrovision on it so bad that it neither played well on tv, nor converted well. It was the tape itself. I tracked down another copy, and the new one was fine.

So considering the age of the tape, along with secondary factors like Macrovision, can reveal compounded issues that cannot be fixed.

[deuce8pro]

Panasonic ES10 would clear that right up. It needs a special kind of sync filter run over it.

I've found this to be untrue.The Panasonic ES10 doesnt correct the tearing issue in pass through.

I've never seen a tape that could not be repaired with this method, unless it was a multi-generational copy, and the error was deeply embedded into the image, not just an error present in the signal. Even a few generations down, the errors can be fixed. It works well with more than tearing, it can correct in-frame wavy lines and an error that I can only describe as a still puddle when a little pebble is thrown into it. That watery look on screen. The ES10 fixes it. I have a test clip I need to upload sometime.

I dont know what results you're getting but it didnt correct the issue of tearing for me and I use JVC SVHS decks. It does correct some jitter but not all of it and sometimes it adds what looks like a drop out in the picture at times. Overall, I think its incorrect to say it corrects tearing.

[lordsmurf]

You're the only person to ever say this, so I would have to suggest your machine is broken.

[deuce8pro]

You're the only person to ever say this, so I would have to suggest your machine is broken.

I am the only person saying it.
I read the reviews on this site saying that it corrected this issue. It doesnt correct it.
In fact, I dont think even a $500 TBC would correct the flagging issue.
I'm disappointed but then again, its the fault of the format.

[Dr_Layne]

I've run into these flagging errors on tapes before as well, but never on a commercially porduced tape. Only on multi generation video tapes. I have had some luck with removing the flagging on some tapes, but those I could not remove it on, I just masked it in Vdub.

A_L