Why no sync issues without using TBC?

[JaviBonus]

Hello everyone! I have been visiting this forum since two or three months ago after register and I have to say a BIG THANK YOU to all the amazing people here helping every noob (like me)

My question is about TBC and synch issues. I have read that many people have those issues with a config similar to mine but I'm not using a TBC, why does this happen?

My config is this:

Funai 17A-600 -(Scart)- Samsung DVD-SH897 -(HDMI)- Hagibis USB3.0 Video Capture Card -(USB)- Laptop

Is it possible that the DVD is synching something or....? I have digitized many kind of tapes, old ones, LP, EP, domestic, commercial... 0 synch issues (lots of chroma noise issues tought, specially digitizing South Park episode, those plain colors are brutal, but that will be a different question )

(Yes, I know that it's a sh*tty setup... I hope i could improve it soon or later but it's hard to get affordable tech where I live )

-- merged --

I don't know how to edit the first post: "since two or three months ago before register ". My bad, english is not my main language and I still have issues with "after" and "before"

[aramkolt]

Short answer is that different capture cards tolerate time base errors to different degrees before they'll actually drop frames and the second part is that the DVD recorder likely stabilizes the signal to a large degree as it converts the signal to HDMI as it is expecting potentially unstable inputs.

[lordsmurf]

Welcome.

Quote:

Originally Posted by JaviBonus

My config is this:
Funai 17A-600 -(Scart)- Samsung DVD-SH897 -(HDMI)- Hagibis USB3.0 Video Capture Card -(USB)- Laptop
Is it possible that the DVD is synching something or....?

With that workflow, you have no idea what is going on, and therefore cannot make the statement that no frames are being dropped/inserted.

By converting to HDMI, you're digitizing the video inside a cheap DVD recorder. You have no way to monitor if frames are being dropped or inserted.

The cheap HDMI "capture" card is merely transferring and re-containerizing the file. (Almost identical to how you "capture" DV, which is merely transferring the digital DV data stream from tape to computer file.)

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(Yes, I know that it's a sh*tty setup... I hope i could improve it soon or later but it's hard to get affordable tech where I live )

In terms of terrible setups, you could do worse. So I guess there's that.

Unlike NTSC, PAL has some allowances for passing "non-standard" (to HD) SD resolutions over HDMI. But it's very recorder specific. I don't know off-hand how that exact recorder handles interlace/AR/scaling, and would have to see samples.

Quote:

My bad, english is not my main language and I still have issues with "after" and "before"

You're doing fine.

Quote:

Originally Posted by aramkolt

Short answer is that different capture cards tolerate time base errors to different degrees before they'll actually drop frames and the second part is that the DVD recorder likely stabilizes the signal to a large degree as it converts the signal to HDMI as it is expecting potentially unstable inputs.

Nope, not it, not this time.

[JaviBonus]

Quoting lordsmurf as a teenager would speak to her favourite pop star

Quote:

Originally Posted by lordsmurf

Welcome.


With that workflow, you have no idea what is going on, and therefore cannot make the statement that no frames are being dropped/inserted.

By converting to HDMI, you're digitizing the video inside a cheap DVD recorder. You have no way to monitor if frames are being dropped or inserted.

The cheap HDMI "capture" card is merely transferring and re-containerizing the file. (Almost identical to how you "capture" DV, which is merely transferring the digital DV data stream from tape to computer file.)

With "no synch" issues I mean that after digitizing a 2 hours vhs (i.e.) sound and image are still synched, that means that everything about synching is ok, isn't it? I have watched the entire file and there is no video jumps, slowdowns, failure on sound, whatever :?

Quote:

Originally Posted by lordsmurf

In terms of terrible setups, you could do worse. So I guess there's that.

Unlike NTSC, PAL has some allowances for passing "non-standard" (to HD) SD resolutions over HDMI. But it's very recorder specific. I don't know off-hand how that exact recorder handles interlace/AR/scaling, and would have to see samples.

About the samples... well, I'm starting a youtube channel with a friend soon. When we publish our first videos I could provide lots of real samples. I suppose the better is to check them "un-encoded" so here you have one. It's taken from a 27 years old tape with 0 care in its storaging. As i said before, the areas with plain red, blue or green colors look awful. I imagine it's because of the mistreated tape, plus not having a tbc, plus a cranky player and a deficient set up but!... it's what i have now

I don't want to share a short sample but as attaching rules say something about not hotlinking images I'll attach a short one. If I can provide a longer one using a link to my GDrive, just tell me

btw... I didn't say that I use OBS because I really admire you and the job you do here and I don't want you to hate me that soon Don't hit me, I CAN'T make vDub work better than OBS, really can't, I'm a computer person, I read forums, googled diferent options, tried 2425 setups and configs but what vDub gives me has the same quality that OBS results but with triple the effort

[lordsmurf]

Quote:

Originally Posted by JaviBonus

Quoting lordsmurf as a teenager would speak to her favourite pop star

Quote:

With "no synch" issues I mean that after digitizing a 2 hours vhs (i.e.) sound and image are still synched, that means that everything about synching is ok, isn't it? I have watched the entire file and there is no video jumps, slowdowns, failure on sound, whatever :?

It really depends on the capture settings. You can "not lose sync", but yet have other errors, from attempting to compensate for dropped/inserted* frames. For example, audio can also be dropped. Or audio can be attenuated (chipmunk or "Barry White"). So on a cursory glance, everything can appear in sync. But on full content watch, errors are obvious. (*Noting that inserts are a method to compensate for drops, but are rarely flawless inserted.)

Other times, it does fully depends on content and playback hardware. Yes, some % of the time can evade dropped/inserted frames, but I'd not bet money on it. The odds are like lottery scratchers. Some winners, tons of losers.

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About the samples... well, I'm starting a youtube channel with a friend soon. When we publish our first videos I could provide lots of real samples.

Sounds good.

Quote:

I don't want to share a short sample but as attaching rules say something about not hotlinking images I'll attach a short one. If I can provide a longer one using a link to my GDrive, just tell me

Attach the short, then PM me link to longer version (Google Drive).
Also Youtube is fine, that's not hotlinking.

EDIT: Alright, downloaded sample, looked. Given the content, sync is not easy to detect. Even the line TBC in a good JVC/Panasonic S-VHS VCR, or even a mere ES10/15 type, would go a long way to making that video look vastly better. It has timing wiggle and chroma noise. Those are the ugliest playback issues of VHS (aside from sync), and are so easy to correct.

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Don't hit me,

Never.

Quote:

I CAN'T make vDub work better than OBS, really can't, I'm a computer person, I read forums, googled diferent options, tried 2425 setups and configs but what vDub gives me has the same quality that OBS results but with triple the effort

Does you system have an Nvidia card?
Cards from the past 5-6 years, in certain setups, smiply do not play nice. (Some laptop cards were bad in the mid 2010s, so this is nothing new.) The Nvidia drivers are to blame, those try to "own" the system too much. Nvidia cards simply do not play nice with other hardware. Great stock (NVDA 10x'd since 2022!), but the graphics cards still suck for video capture users.

Other options, if not that. But it's a common problem.