AV sync problems with new frame TBC?
 

Hello everyone!

I recently bought a new Frame TBC model Cypress CTB-100 and since then, the audio and video are desynchronized after an hour. Before adding this Frame TBC to my setup, the audio wasn't desynchronized from the video.

I have thought that it is a problem of the timing configuration or as the audio doesn't go through the Frame TBC and the Frame TBC has to process the image, it can cause an A/V desynchronization.

This is my setup: JVC HR-S3900U > Panasonic DMR-ES15 > Cypress CTB-100 > ATI TV Wonder HD 600 USB > Windows XP > VirtualDub 1.9.11 (HuffYUV). All using high quality S-Video and RCA cables.

I attached my timing configuration, my setup and video sample.

This is my computer:

Intel Core 2 Duo E6700 2.66GHz
Kingston KVR66702N5/1G DDR2-667 CL5
AsRock 775Dual-VSTA
ATI Radeon 9250
Western Digital 40GB IDE (OS)
Seagate 1TB HDD CMR SATA (Captures)

Thanks!

Timing looks good, just make sure to tick the two "Drop frames/Insert frames" at the top. That way if things get congested, it will at least tell you on the ticker on the side.

If anything, should you get reported dropped inserted frames, you can rewind from a specific point and then stitch them together in Avisynth to the frame (which should be used anyway if you're going to clean these up later for final delivery).

Hope this helps!

If I mark that options, what will change in the capture?

By having both of them disabled, you're putting dependence on the capture card to maintain sync, so when there's errors, the capture card's default go-to is to screw up the sync.

Which in turn, you won't know unless you have these tickers enabled in VD, so the software handles sync instead.

Your recommendation is that I check both options and try capturing again?

Yea, give it a go and see how that turns out

What is the reasoning behind adding the Cypress CTB-100 since you didn't have any problem without it?

Thanks. When I do, is there anything I need to watch out for while capturing?

Overlay or preview?

Thanks!

Disabling/unchecking the first two options merely disables detection, nothing more. Bad.

So, what could be the solution or the cause of this problem?

Thanks for your answer.

The TBC may be defective. Likely, in fact. I'd need to see extensive photos of inside and out.

Here you have all the pictures attached of the TBC.

Does it work better if you enable "sync audio to video...."? I've always gotten drift if it's set to "do not resync".

Also as latreche34 noted, any specifici issue that caused you to add the frame TBC? The output from the ES15 should be stable already.

Could you tell me all the options that you recommend for the timing tab?

Thanks!

Why do you add questions instead of answering the questions from people trying to help you?

Sorry, I use the Frame TBC to clean the signal as indicated in this forum.

Confirmed, this is a defective model. It actually causes the errors it is supposed to remove.

To me, this is a somewhat silly question. It's like asking why a car needs gas, or why you need to eat. TBC is an essential. Sure, to try to save money, you can pour whiskey in the gas tank, or eat Twinkies, but it's not suggested, there are consequences. ES10/15 alone is not fully filtering, the output can be "gappy" in terms of frame release differences, as it's just a plain frame sync, not a TBC frame sync that rebuild frame timing.

To quote an article:
.. and that's it.

A frame sync TBC, on the other hand, ingests the signal, strips and replaces as needed, and releases it in a timed 29.97 or 25 fps basis. Not just randomly. The "gappy" nature of frames is a reason that causes dropped frames. And dropped frames often thus cause audio sync flaws.

Now a flawed Cypress chipset processes badly, and induces more errors, often merely amplifying problems that already exist. So if you're getting audio sync or drops, using a flawed Cypress, the root cause is the tapes suck. Of course, almost all VHS tapes suck, so that's not unexpected. The Es10/15 made it look pretty, removed wiggles, removed tearing, but the frame timing flaws are left 100% intact.

While I can appreciate the desire to "go cheap", and use a ES10/15 type recorder as a TBC(ish) stand-in, this is why I always state that it has limits, warts, imperfections, add issues to the workflow. It's not a TBC replacement. Be careful of suggesting that it can replace a TBC, or that a TBC is not needed at all.

Had this been a good TBC model, it would have been a great add to solidify your workflow.

So, has no use? Dammit.

That's your point of view, and I do not agree. In my experience and with my material I do not need a frameTBC. Introducing it will cause a degradation because additional element in the chain, and zero benefit.

Of course in other cases you need it, but it is not always mandatory. Nothing to see with gas and food.

And my impression is that OP did not need a frameTBC neither, he just blindly followed a generic suggestion.
But that's just my speculation, I do not know his captures. That's why also latreche34 and hodgey asked the same question!

I'm pretty sure the OP is miss informed about how a frame TBC work, Cleaning a signal is not actually a technical word nor that's what's actually happening. The frame TBC does not clean the VBI signal, it replaces it completely with a new digitized one. If the signal from the tape is good, leave it alone. The frame TBC has no effect on the picture quality and should not have, Its main function is to stabilize the frame and avoid audio drift. From the OP's samples the frames are as stable as they can be and he already stated that he did not have an audio drift without the frame TBC.