TBC and dropped frames... (solved)

[Cole]

I have had a couple of captures recently with dropped frames, but it has not been the capture program that is at fault (WinDV in this case reporting no dropped frames).

I then wondered, could this be the TBC in my JVC HR-S7965 that is 'compensating' for a bad dropout or picture faults on the video, or is it simply that the VCR needs cleaning (which will be done).

The first time I noticed this was when I captured some commerical VHS that had not been looked after very well. When I got the tapes, they were left without having been fully rewound. In the instance that I discovered the missing frames and went back to the orgininal VHS, I found that there were picture problems (scrolling lines) but on the second capture, no frames were dropped!

However, this has also happened on a couple of recent clean i.e. looked after tapes.

Possibly this may be more 'Capture' than 'Restoration', but the advice that the TBC may cause dropped frames is what I am really asking about.

Many thanks for any help.

[lordsmurf]

Cole
*My Video Set Up
*VHS Output Comparison

Nice couple of pages there.

[Cole]

Cole
*My Video Set Up
*VHS Output Comparison

Nice couple of pages there.

Thank you, Lordsmurf. I really appreciate that.

It is always nice to receive positive feedback, but when it comes from one of Videohelp's experts...

[vhelp]

They would really have to of been bad frames in your VHS.

* Did you try capturing without the TBC ??
* Also, did you use your advc-50 card on this ??

I've never experienced any dropped frames in my advc-100
captures, except for when I had bad timings w/ the card
catching up with the hd, due to hd cache over flows or
something like that. This usually happens when I have
used up most of my system resources, and go straight
to capturing.., but is mostly due to random glitches
in the chain somewheres. Usually, a CANCEL and RESTART
of the capture process cures this for me.

Sometimes a change in any system components can cause
a change in capture performance or stability. For example,
if you instaled a software that molested your DX; DMS; or
DS; or other driver setup somewheres on never-never land
of devices and things. Just because you reinstalled a
given driver or DMA or DX/DS does not mean everything
else will *still* be the same later. Sometimes, its
days or weeks before you find this out, only to forget
that some time previously, you installed or reinstalled
something.

-->

-vhelp 3422

[Cole]

Yes, they were captured with the Canopus ADVC-50, which is why I believe that the frame drops originate from the VCR's TBC.

I have not tried capturing with the TBC off in this instance as I had only just discovered the issue with the last few capures (when watching the resultant DVD ).

They would really have to of been bad frames in your VHS.

In the most recent incidents where dropped frames occur this was not the case, which makes me inclined to go down the 'dirty' VCR avenue first, as thinking about it, recently my recordings on the JVC-7965 had begun to give drop outs about the same time as the dropped frame issue began.

One of my recent recordings had a really bad drop out of about two/three seconds long, but my very last recording (over this last weekend) seemed to be really clean. This makes me think that I may have picked up some dirt from the old VHS that I mentioned in my first post and the that large dropout is where the dirt may have been dislodged (is that feasible?).

I will give the VCR a clean (and will do so after every poorly kept VHS used) and hopefully this will no longer be a problem. Will report back if it is...

Thanks vhelp.

[vhelp]

I have a theory of my own regarding this mysterious "glitches"
showing up on my tapes when I least expect it, when I shouldn't.

My theory is like this ...

Somewhere inside the VCR unit, the tape is becoming too magnetically
contaminated and/or collects some magnetic dirt, and this dirt
gets pasted onto the tape area, and shows up as "glitches" like
your drop-outs. Or.., read on..

Another thing to consider is this ...

Something happended to the tape while it was loading/unloading
and the machenism stretched it, thereby distorting the original
work.

If the above did happend, then any number of "glitches" could
show up in whatever form possible. Currently, in your case,
it seems to have come up in the form of "drop-outs".

After a completed run with a vhs tape ...

Fast forward to the end of the tape, *and then stop there*
and remove it from the vcr. There's a reason to this method
of madness. If user FW the tape to end, and stop, and then put
back in storage (shelf) ..then, the next time user goes to use
it for a project, the user will RW the tape after it has wormed
up. Why ? Well, IMO, this will loosen it up for a cleaner capture
project. Any chance of tape area becoming sticky-like, will
have been undone during the immediate (room-temperature-ready) RW,
and a smoother capture will result in less "glitches", like
stickyness or whatever.
.
If user FW and then RW the tape in one step, and then follow it
to storage/shelf, the next time user goes to give it another run
inside a VCR, it will most probably suffer some stickyness to
other tape areas. And during the capturing phase, these sticky
areas will become "glitches" in the final capture.
.
I believe it is better, when you are finished with a given vhs
tape, that you FW it only, and put back to storage. Then at a
later date, should you require work on this same tape, you can
proceed with the above process (and below) for the best performance

Ok.., so then, after FW 'ing the tape (above) ...

At a later date in time, ..when one is planning on doing some vhs
work, what they could do is turn on the vcr and let it worm up for
1/2 hr or so, and then put in a vhs tape in the unit and then let
that tape worm up to the vcr's temperature. Following that, you
would proceed to RW the tape to the beginning, and begin your
capture process.

-->

Just how much this is all worth in trueth, is subjective at best.
But, its worth considering, when contemplating restoration
techniques, etc.

-vhelp 3427

[Cole]

If user FW and then RW the tape in one step, and then follow it
to storage/shelf, the next time user goes to give it another run
inside a VCR, it will most probably suffer some stickyness to
other tape areas. And during the capturing phase, these sticky
areas will become "glitches" in the final capture.

That is interesting as I believed that if a tape has not been played for a while, FW and then RW will 'loosen' the tape and thus give it a better 'transport' in the VCR when playing back.

Interestingly enough, FWing and RWing is exactly what I did for all of the tapes that I had problems with. The original offending VHS tapes when I got them, where stored at some halfway point...

..when one is planning on doing some vhs
work, what they could do is turn on the vcr and let it worm up for
1/2 hr or so, and then put in a vhs tape in the unit and then let
that tape worm up to the vcr's temperature.

This reminds me of my very first VCR (Fisher in 1985: Top Loader, non-hi fi, remote control on a five metre cable plugged into the front... ) that had a LED which came on if there was any condensation inside the machine.

You may have something there, as my JVC isn't on all the time and I only turn it on for VHS capture. Maybe half an hour is a bit long as my JVC is by no means stored in a cold room, but maybe I shouldn't go staight into insert tape and play immediately.

Still, I bought a non abrasive VCR cleaning cassette and will make a start with that...

[Cole]

Oh dear! This issue has reared its ugly head again. Since posting last time on this subject, I have had two tapes that have caused jumped frames and picture freezes.

They have both been pre-recorded tapes (i.e. commercial) and both aprox. released in 1996, but of different origin (i.e. one company is BBC Video and the other BMG).

To solve the issue with the first tape, I used a Panasonic NV-HV61 which played the VHS perfectly and gave me a perfect recording, but the picture reporduction of this VCR is no-where near as good as the JVC HR-S7965.

I am faced with this again; I have a tape which refuses to play properly regardless of how the settings are.

As for the settings: I can't use the TBC with this tape as it is causing tearing at the top of the picture (the tape also has Macrovision). I can't use the video stabaliser as it causes dropouts on the soundtrack, and whether the BEST picture is on or not, makes no difference.

Using a cleaning tape doesn't seem to help either (unless this is an occasion where I need to open the top of the video and give it a really good clean out). Having said that, it seems odd that this is happening on certain tapes and not all, if this is a clean-head issue.

Any further advice on this will be appreciated.

[davideck]

It sounds like you are in need of a DataVideo TBC.
It provides an uninterrupted sync signal at its output independent of any disturbances in the video input.
The JVC internal TBC, unfortunately, does not do this.

[Cole]

The capture problem still happens with the TBC in the JVC is turned off as well. Is there a different method of signal output from the JVC than an ordinary VCR?

I looked up the DataVideo TBC. Interesting, but currently, a little to rich for my pocket

FWIW, I have captured two off-air recordings since the tape which is causing the issue, and they captured with no problems at all.

[Dragonsf]

Intersting thing, as I have the same problem: Same tape could be captured some month ago, but now has some quirks, I don't understand: Audio is occasionally interrupted with no signal (length around 1 ms) and video is sometimes accelerated (looks like dropped frames, but there aren't any- can be checked with VDub). I tried WinDV and DVIO with the same issues. After converting to DVD the same problems playing back (on PC and standalone).
The only things, that was changed were the graphic card (both with the same driver). And a defective DV codec (GSpot told me, it was defective). As I learned, that a codec doesn't play any role during capturing - without dropped frames BTW), how could such things influence capturing?
I capture from JVC S-VHS with ADVC 300.CPU load was 20% all the time.

[davideck]

The capture problem still happens with the TBC in the JVC is turned off as well.

That makes sense. The JVC TBC does not fix this problem, but it isn't causing it, either.

As your VCR plays back a tape, it may occasionally experience a dropout around the vertical sync region. This can confuse your capture device, causing it to add or drop a frame as it tries to resync to the input. The results will vary from tape to tape, and may even vary each time you try to capture a particular tape.

The DataVideo TBC puts a stop to all this by ALWAYS providing a clean uninterrupted sync signal at its output, even while it resynchronizes to its input. The capture device never sees a disturbance.

It's a shame that the JVC TBC doesn't do the same thing; I suspect it would have been an easy feature to include.

I was struggling with audio/video sync issues on my home videos that would accumulate during a capture as the tape played through dropouts and blank regions. These issues were completely eliminated by my TBC-3000. It was money well spent...

[Dragonsf]

With correct TBC, the MacroVison CP would have been defeated with the JVC.

[vhelp]

@ Cole

(sorry for the long and boring post) ...

Your whole problem is MACROVISION. Plain and simple. MV effects pretty
much everything.. including TBC's. And just because a TBC is a TBC does
not mean that it will cure everything - it won't. As experience has
shown. I know it has, with me. Anyways.

The moment you take out an MV recorded tape, everything is wonderful
again. Put back in your MV tape, and havic is recond.

Curling is a big deal to me. Even my tbc [tbc-100] does not cure it.
Sure, it will strip most of the signal out and re-condition it with
new signals. But, that's about it.

Your VCR is pumping out MV signals to your output connectors. It has to.
Because that is a part of the contract w/ MV in order to deal with the
big-wigs. So, every current VCR you see out there is MV switched in
"always-on" mode.

Now, it is up to your capture device to "ignore" this (or, these) strange
signals that the tape/vcr is pumping out.

Thus, for instance, most if not all, BTxxx capture card will capture a
given MV source w/out problems. Nice and clean. My ATI-TV Wonder VE
card captures beautifully.. except for the Line Noise from the internal
working machinices. But throw in a brand/make capture card that serves
the devil, MACROVISION, and you have all kinds of problems.. like yours.

In my experience capturing from VCR and TBC's, I have found that when
the source tape has MV, the VCR and TBC can play tug-a-war with ea. other.
And, even resorting to the VCR's options, such as Stabilizer and Video
Calibration will have "adverse" affects on capturing, when the capture
card/device serves MV only. Non-MV has no problems.

And, even if you can get your TBC to produce clean and stable video, the
chances of your video frames showing "jittering" is a good chance that
your source will NOT be IVTC 'able. I suffer from this, if I use my
TBC-100 and my VCR together and my capture card is my ATI-Rage Fury Pro
or ADVC-100 (with MV enabled) unfortunately.

My VCR is the JVC S-VHS HR-S3910U

When you throw in an hardware capture device like the ADVC-100 and enable
the MV ignore feature, it captures perfect and CLEAN avi's.

I choose to stay with DV (my advc) and ignore the 411 issues that follow
it, because most of the 411 issues (ie, chroma noise; blocks; etc) are
the result of odd Sampling from the MPEG used; or from coded MPEG's that
are using MPEG-1 sampling inside MPEG-2, for instance, etc.

I have yet to see a clean source from from a capture card. That is why
I use DV as my portal to capture.. it's beautifully clean.

-vhelp 3610

[davideck]

Cole - I was addressing your issues of frame dropping. I missed the bit about Macrovision.
The Datavideo TBC helps with that too...

[Cole]

Thanks for all the help and advice everyone.

When you throw in an hardware capture device like the ADVC-100 and enable the MV ignore feature, it captures perfect and CLEAN avi's.

The capture device I am using is still the ADVC-50 and I have removed the sixth jumper switch to defeat MV. I do agree with the DV route for VHS captures and I have had such sucesses over the last couple of years with the 50 and am very pleased with it. When I discovered the MV "hack" in the ADVC-50 I was over the moon and captured several commercial MV tapes with no problems.

However this issue, that I am having, has definitly co-incided with my purchase of the JVC HR-S7965. Thankfully, not that many, but on the odd occasion such as this it does get a bit frustrating that one has to rely on "older" set ups to achieve the capture.

As your VCR plays back a tape, it may occasionally experience a dropout around the vertical sync region. This can confuse your capture device, causing it to add or drop a frame as it tries to resync to the input. The results will vary from tape to tape, and may even vary each time you try to capture a particular tape.

Yes, the tape's picture drops or freezes at different places. So this seems to follow. I have previously had tapes that have dropped a frame once during the whole playback or in the case of the tape that prompted me to post yesterday, was so bad as to give the appearance of the tape being unplayable.

When I attempted to capture previous tapes where this issue occured, the JVC had the problems, but the Panasonic didn't. However the Panasonic doesn't have any menu settings for picture control. I can only surmise from this that the JVC is therefore a more sensitive machine/is giving out a more sensitive signal, which as you say is giving the ADVC-50 a hard time.

The MV seems to be a part of this, as this had never happened with any off air tapes.

At some point, I may see what the output looks like to a normal televison from the JVC, which will tell me once and for all if this is an issue with the capture device's problem or an issue with the JVC.

Would the cheaper Datavideo TBC-1000 also do the job (although this is pretty expensive too)?

[davideck]

...the tape's picture drops...

Could you describe this a little more? What does this look like?

At some point, I may see what the output looks like to a normal televison from the JVC, which will tell me once and for all if this is an issue with the capture device's problem or an issue with the JVC.

That would be a good test.
If your problem is only MV related, then the TV picture should be stable.
If the TV picture is jumping around, then a TBC might not help.

Would the cheaper Datavideo TBC-1000 also do the job (although this is pretty expensive too)?

The TBC-100, TBC-1000, and TBC-3000 all use the same TBC core.
The TBC-3000 is esentially two TBC-100s with proc amp adjustments and synchronized outputs.

[Cole]

I may have not used the right description; drops in this instance doesn't mean anything like jittering up and down; sorry about that!

What happens is that the picture freezes momentarily and then jumps on; a bit like having a few frames removed from a film.

Other times the picture freezes for quite a while. It may move to the next frame after a few seconds, or on occasion catches up to the current outputed frame. On other occasions, it just freezes and doesn't move on at all. However, at this point, I have turned off the operation as the capture has become pointless.

[lordsmurf]

It sounds to me like the capture device is the picky one being the problem.

[vhelp]

- Just to rule out ADVC attributes and MV ...

I was wondering how much trouble it would be to run a test
scenario but with a BTxxx card in the chain of things.
I am wondering what your MV handle'age would be w/ MV tapes
and a BTxxx card and your VCR (w/ various options settings
for ea. capture) and reviewed results thereof.

I would say that the JVC brand VCR you are using is causing
the freeze up and sync issues. Not because it is bad, but
because it is more in tune with MACROVISION signals and your
TBC chain.

It is obvsious that you won't experience the same issues when
used in older vcr equip which serve less in MV and so forth.

Cole, in my chain of events, using my JVC (older generation of
todays JVC models, which in my opinion, is the same as mine,
but with new lables associated w/ catch-phrases, etc. yada yada)
when I use a MV'less capture device, and I turn on the DISPLAY
(TIP: I use as a guage for phenomina.. ie, your issues, for one)
and capture, I use the capture's video window to show me what is
actually going on during the capture stage. You can't use your
TV for a guage, because your tv is receiving a different or
modified signal, and is not the same as what your capture card
is receiving. Thus, two different outcomes that you will never
be able to finger with any definative resolutions. As I was
saying..
And I watch and observes my video window during capturing, and
I note the DISPLAY text as it captures. As I do so, I quickly
go into options/settings (whatever it is on your given VCR) and
adjust option settings, and review results of the video window
and the DISPLAY text during capturing.

I do this (the above) for a reason..

A) for a technique (as I am now sharing with you all here - officially) and
B) to note any odd phenomina like.. ie, text bobbing up and down, etc.

When I see the DISPLAY text bob up/down, this is an immediate
indicator to me that I will have problems with my Field Order inside
my AVI during the video processing stage. An example of findings
from this ex. phenomina would be incorrect Fields causing my IVTC
process to fail or give unpredictable results.

The above is just an example of what I go through in my experiences.

The other TIP, when working with tapes that consists of MV, is that
you have to realize that there are many flavors of MV. And you can
not re-use the same setup in a previous tape process, if the tape
is of different video content.. ie, one tape is Commercial, and the
other tape is a recorded Commercial, for instance.. or a totally
different Commercial tape/movie. Course, two same movies with the
same puchase of such two tapes would result in the same symtoms..
course.

So I was thinking, as a test, to play around w/ other capture cards /
devices and run a battery of scenarious of tests with them.
The reason I suggested this is because I have just recently gone
through this process w/ my setup in these last passing weeks. So, I
know what the outcome you are expected to conclude as well. In any
case, it is good experience, and will give you more scares to boast
about :P

Well, the weekend is almost here. You should have lots of fun, starting
today. So, have fun

From the Video Workstation of,
-vhelp 3611

[Cole]

Well, after a bit of experimentation, I am now convinced that the problem is to do with the following:

The ADVC-50 is definitly having some issues with the JVC's signal with this tape (TBC on or off), as normal television playback had no problems at all.

With an intermediate stabaliser/Macrovision defeat item (I tried a Datavideo VP260 which I got for about £7 on ebay) had an adverse effect: the tearing at the top of the screen which was something near a sixth of the entire picture, with red and green blotches appearing under this tearing, but oddly, the tearing only started about fifteen minutes into the tape and not from the beginning.

I have then got out the Pannasonic NV-HV61, connected this to the ADVC-50 and as before, a perfect capture (although not as clean a picture as the JVC would have provided) which was the way I dealt with the previous tapes that have had this problem.

Therefore, I would surmise that the JVC's signal is more sensitive and involved as the Panasonic: rather like years ago where a hi-fi record deck would reproduce more noise on a poorly kept vinyl album, than would a cheap nail-for-a-stylus record player. The ADVC-50 must be having issues with this.

Save for spending a lot of money on a Datavideo TBC, the only thing I can do about this is to just see how my captures come out and if they are jumpy, it's back to the Panny!



Edit: It seems I spoke too soon. The Panasonic capture although much much better, was by far from perfect. The recording started dropping frames someway into the video, but they were the 'snipped' frames only (momentary freeze and then the jump to current) and no complete freezes. Seems a Datavideo TBC may be the only trusty way to go as this tape is really giving the ADVC-50 a very hard time.

[Cole]

Further update: I have taken the plunge and ordered a Datavideo TBC-100. I hope to report back as to how this had helped (please let it help: £235 is alot of money when you've just been made redundant! )

[vhelp]

I have the tbc-100 [not the -1000 model]. The 100 looks like a
pci card (though it is not) and has no contact on the edges.

The power is drawn from a free connector (those white power plugs
from your power supply in the case - whatever they are called)

A word of warning ...

When you first get it, be VERY CAREFUL of plugginn (inserting) the
white power plug end into the female end the tbc-100 board. If you
are not CAREFUL, you will pry it off the i/o board, and it will be
permanent. I suffered from this casulty. I didn't realize how
sensitive it was, as it is *hooked* onto the i/o board. Anyways.

For now, on my tbc-100 i/o board, the female connector just hangs
on the wires that are soldered onto the i/o board. But, when I
use it, I am VERY CAREFUL of inserting it.. otherwise

Please don't make the same mistake as I did

I hope everything works out for you in this situation. Good luck

-vhelp 3621

[Cole]

Thanks for the heads up vhelp.

Got the TBC-100 from here http://www.holdan.co.uk/acatalog/TBC_100_PCI_Style_TBC.html

I understood that the PCI card took power from a PCI slot, but with a close look at the picture, it may not be the case.

I won't get the device until Tuesday at the earliest, but I will be very careful in installing it.

[Cole]

Maybe a bit premature on coming back on this one, but I took delivery of a Datavideo TBC-100 today and installed it. The first tape I captured was the one that had been giving me all the trouble.

Not one dropped frame or freeze. There was still an issue with tearing or rather a fuzzy bar accross the top of the screen, but this was dealt with in the encode process where I cropped this off (mostly in the overscan area anyway).

Thanks to every one for any help or suggestions. It has been greatly appreciated.



P.S. @vhelp I was careful when I installed it and I didn't break anything

[gammer]

There was still an issue with tearing or rather a fuzzy bar accross the top of the screen, but this was dealt with in the encode process where I cropped this off (mostly in the overscan area anyway).

I recently had an issue like this on a Holywood VHS tape running through a Leitch VT2500 TBC.
If I did't use the TBC then the video was un-watchable. But if I ran the video through the TBC it was watchable except for a blurry tear band accross the top of the video. I too found that it was covered up by the overscan area.
This is the first time I ran into this problem; one thing to note: is that the tape I was using had been heavily used and was very old. Not sure if that had anything to do with it or not?? Probably though.
I think I read on Lordsmurf's page that this tear line is a rare issue with TBC's on certain tapes. I could be wrong though.
In my case I tried several different VHS players but all yielded the same results.

[Cole]

I think in my instance, it wasn't the TBC causing the tearing. I don't think it actually was tearing though, but some reaction with Macrovision on this tape. At any rate, the tape itself had some serious problems, which in turn caused me loads.