Hi8/Digital8 digital conversion options?

[lordsmurf]

Quote:

Originally Posted by radiokom

Well, audio delay is about 3-5 sec from start to end within 3h. At start there is only hiss (similar to audio tape hiss), after video start and then audio with delay. And when video stops (after 3h) audio stops the same 3-5 sec later. Hard to imagine this is because of dropping frames.

P.S. It is constant audio delay.

In the analog ingest realm, true constant audio is often still caused by initial frame dropping. Sometimes by divergence in the workflow path (such as not routing audio through ES10/15).

If a mere audio shift exists, it can be adjusted in VirtualDub, by +/-ms. In fact, if this shift fails at sync, it proves in-recording sporatic dropped frames.

Given this discussion is about BM cards, I'm not convinced your experience as simple shift. BM cards dropping frames is a known known.

[aramkolt]

Audio shift is a real thing (could be looked at as video delay), and basically guaranteed if you're using a frame TBC since it buffers a frame or two which results in at least a 1/30th - 2/30th second of a delay, but it should be fairly constant throughout the capture. A few of the Snell and Wilcox TBCs will actually display what how much the video is being delayed through it live and it doesn't change much.

I've had a theory about the best way to know what your specific audio delay is in a certain chain would be to use a linear time code generator which visually burns in/overlays a generated timecode on each frame and also creates timecode audio. From there, you'd just run a stable source through it like a DVD player or pattern generator and capture both audio and video and then compare the decoded timecode audio to what is seen burned into the frame. The difference between the two at any given point is the video delay of that chain. Feeding it an unstable source shouldn't change the delay, but the benefit of using it here is that no frames should be dropped that would have the visual timecode burnt in.

The key with dropped frames though is that the audio should get further and further out of sync the longer the capture goes and will get more out of sync randomly, so in other words, if the video is 1 second ahead 15 minutes into the capture, it could be 5 seconds ahead at 30 minutes into the same capture if a bunch more frames were dropped between the 15m and 30m mark.

The different capture solutions compensate for dropped frames differently, so you might not get the audio sync problem with certain sets of preferences (even without a frame TBC) with some capture apps/configurations. Frames may still be dropped though.

[radiokom]

Never had such a problem with PCI express BM cards, only particular USB. All was tested on the same PC with the same VCR and the same video tape. For capture and edit I use Adobe Premiere 6 where it is really not a problem to sync audio to video after capture. When I noticed USB version does not work as it should I simply stopped to use it. I have no experience with dropping frames by BM. At least Premiere capture log do not show something extreme. Yes, there are dropped frames sometimes, with damaged tape especially, but this is understandable.

P.S. I still have this card somewhere (I never try to sell someone something what is not working for me) so it would be possible to make some tests again if I will find it.

[lordsmurf]

Quote:

Originally Posted by aramkolt

Audio shift is a real thing (could be looked at as video delay), and basically guaranteed if you're using a frame TBC since it buffers a frame or two which results in at least a 1/30th - 2/30th second of a delay,

No, not that long. The frame delay is one field to one frame, so 1/59.94 to 1/29.97 (or PAL 1/50 to 1/25).

For 29.97fps, 1 frame equates to about 35ms. (Or PAL 40ms.)

Human perception doesn't start to notice audio divergence until you exceed 100ms, approaching 200ms. (FYI, AI chatbots give lower numbers, but AI chatbot are "artificial idiots". I sometimes run facts by chatbots, to see if they're accurate or crap.)

In effect, offset at this tiny ms is imperceptible.

This also assumes the source is 100% correct, which it never is. There will always be some % of lag, from the beginning, simply because of physics. Light travels faster than sound.

Quote:

Originally Posted by radiokom

For capture and edit I use Adobe Premiere 6 where it is really not a problem to sync audio to video after capture.

Do you simply drag the audio timeline over a by a few frames? Or do you do more? If more, then it's not a static/constant delay.

Quote:

Yes, there are dropped frames sometimes, with damaged tape especially, but this is understandable.

A good TBC generally won't allow drops here either. All tapes have some % of slop, as consumer formats were chaos on mylar. That is where dropped frames come from.

[radiokom]

Quote:

Originally Posted by lordsmurf

Do you simply drag the audio timeline over a by a few frames? Or do you do more? If more, then it's not a static/constant delay.

Video and audio was (1) the same length and (2) perfectly "in sync" if synchronized manually in Premiere after capture.
So it is simply audio delay, not "out of sync" completely.
But audio delay was 3-5 seconds for particular record. So if it was 3sec, then 3sec from beginning to the end. If 5 - the same. I didn't have the health to look into any reason for this, especially when Blackmagic itself couldn't even tell its dealer (my friend) anything relevant, except "try to restart the computer."

[lordsmurf]

Quote:

Originally Posted by radiokom

Blackmagic itself couldn't even tell its dealer (my friend) anything relevant, except "try to restart the computer."

Old version of same advice = "Did you try to hit it or kick it?"

[radiokom]

Quote:

Originally Posted by lordsmurf

Old version of same advice = "Did you try to hit it or kick it?"

Aha! I remember those tube TV when this method worked (sometimes, until a certain point)

I thought that the card might be cursed, and I thought that I should call a priest (it was not clear which one, there are many of them and you never know or it will turn out worse).

But then my friend suggested to leave it alone and use the cards that work, so as not to accidentally release a demon from this one as a result of exorcism, not understanding where it will end up!

Quote:

Originally Posted by lordsmurf

A good TBC generally won't allow drops here either. All tapes have some % of slop, as consumer formats were chaos on mylar. That is where dropped frames come from.

Chemical degradation of tape with age is one thing. But there are still lot of people who found somewhere in attic their marriage tapes from 80s together with VCR. And what they are doing? You know it, I am sure! They connect this VCR to something, turn on and try to play tape. And it works! And it depends if suspicions something is wrong appears within 1 minute, 3 minutes or later, in result tape is damaged 1, 3 or more minutes from beginning. And in this case there are no TBC what could help so dropped frames are common.

[lordsmurf]

Quote:

Originally Posted by radiokom

But there are still lot of people who found somewhere in attic their marriage tapes from 80s together with VCR. ... They connect this VCR to something, turn on and try to play tape. And it works!

"Works' is no the word I'd use. The tape gives an output, but the output looks like ass.

Quote:

dropped frames are common.

It doesn't have to be that way. This is why TBC exist.

[radiokom]

Quote:

Originally Posted by lordsmurf

It doesn't have to be that way. This is why TBC exist.

This is the thing I should learn more about. In my experience, if tape is seriously mechanically damaged by transport (because of tape skew etc.) some dropped frames (at least in capture log) exist along with, of course, distorted image.

[Gary34]

I went from a shuttle and a composite VCR to a 1980p ag, Pinnacle card and a frame TBC. When I used a regular VCR with the shuttle it dropped a bunch of frames. When I replaced the regular VCR with the 1980p ag it dropped way less but still dropped.

When I got my Pinnacle card I hooked it up to a regular VCR with no TBC and noticed it handled the signal way better than the shuttle. It dropped too but not as bad. With my frame TBC in the workflow I get no drops.

Yesterday I had a VHS-C SLP tape that squealed when I played it and the tracking was awful. I captured once then thought maybe a transplant would help so I transplanted it to a full size cassette and captured again then as a last resort I put it in my composite cheap deck and messed with the guides and it didn’t track well no matter what but I had no dropped frames and no bouncing around when capturing. I never did capture with my composite deck I just saw how it wasn’t helping with the tracking in my CRT and decided not to do that capture. Only when it was on my CRT with the composite deck did the picture bounce around. I’ll peace together the two captures because that is one of the more important tapes I have. Or maybe I’ll just use the one after the transplant. It has like 66 lines at the bottom and top I can crop to hide the bad tracking lines because it was shot with a VHS widescreen look. It’s not perfect but I was happy with it because I feel like a lot of transfer methods couldn’t of got that footage with no drops and the picture being really steady like that or maybe couldn’t of got it at all.

[radiokom]

In this case is one question about VHS tapes (if they squealed). Analog audio tape squealing is commonly caused by one of 2 factors - SSS (sticky shed syndrome) or lubricant dried out (mostly cassette tapes, this is why sometimes Studer A80QC is the only way to reproduce cassette tapes). SSS can be cured by baking or in dehydrator (food dehydrator works . But some cassette tapes (mostly Ampex) sometimes can be played back only after additional lubrication with silicone oil (and after wind out on spool and on Studer A80QC). Terrible precedure, but if it is unique recording, no way. So what kind of degradation cause squealing of video tapes?

[Gary34]

Maybe squealing was the wrong word. It made this noise.

[aramkolt]

Squealing is usually sticky shed on U-Matic/VHS/Betamax also, but I've yet to encounter it in person on anything other than U-Matic though.