Frame inserts due to audio sync correction?
 

Moved from original thread, was OT there. -LS

I was under the impression (although I could be wrong) that the occasional (like you say 1-2 an hour) inserts can be due to audio sync correction - that's something I have a memory of reading somewhere years ago though, I can't vouch for if it's true or not. I've never had an issue dropping the odd frame personally.

Of course a LOTC condition will send the capture potty anyway, so it's quite a flexible thing that needs to be taken in context. I had one this afternoon that dropped several hundred frames due to tape damage...

Drops and inserts can have several causes, both source and capture side.

What remains true/constant is that it creates either (1) desync, or (2) choppy lost data. Those are the only choices.

I don't know what "LOTC" means, but dropping frames in masse is either (a) lack of frame sync TBC, (b) I/O errors on the capture system. Again, there are only two reasons here. I know you operate with out any TBCs (which I find unacceptable for pro work, but we'll sideline that discussion here), and this is the consequence.

Inserts can be an attempt to correct for sync, but only if set as such. Audio skew is generally maintained by altering the clock speed. But that can have unacceptable issues as well, be it "chipmunk" or "Barry White" audio. You can attempt to constrain the audio clock*, but the outcome may be more drops and inserts. It's a delicate balance, and the reason why quality VCRs, capture cards, and TBCs, are so important to a workflow.

(It cannot be locked, only constrained. See also, a reason why "audio lock" is nonsense. Noting the main reason is because no such function exists, that Canopus-origin non-eixstant "feature" is the byproduct of marketing idiots not understanding specs, and munging the term. Those crappy Canopus DV boxes can, and do, drop frames and lose audio sync.)

"Dropping the odd frame" is more often on the capture system side. You have an I/O lag due to not reformatting the capture drives enough, or at all. The time it takes to seek an open block results in drops. See also why capturing to SSD can be bad, as it's non-contiguous in nature. And yet, sometimes it is indeed the source, even with TBC. It doesn't even have to be "bad" (visually) source, merely bad (signal) source.

I do agree, I don't sweat over 2-3 drops per hour, but assuming the capture is no more than an hour. If you cram a 6-hour tape in, and it drops "only" 3 per hour, you'll have audio skew that's noticeable off by the end of that 6 hours. Not so much with inserts, but you'll have duped frames. Rarely is it a single drop here, single drop there, but 2-3 at once, noticeable stutter in the video.

In this thread:
- VC500 not great
- Hi8/Video is drop-happy, so this is expected behavior
- good VCR for VHS (awful for DV)

Where the hell did you get that from?
I think you owe me an apology!
I certainly do not, nor have ever operated any transfers without a TBC, evidence or apology please.
For heavens sake man, I've even posted pictures on here of some of our capture racks and setups.
I'll await an apology.

In at least one thread, in recent past weeks, you were arguing against TBCs.
This is one of those threads: http://www.digitalfaq.com/forum/news...html#post79138

If you do use TBCs, great, <phew> :hot: ... I'm really glad to hear this! :congrats:

But why argue needing TBCs? The goal here is helping others get quality conversions, not appeasing the low-knowledge or cheapskate users of society, reinforcing their wrong ideas on why TBCs matter and are required. They need to be educated, not coddled.

You can get more nuances on what works, and what doesn't, and what sorta works+doesn't. Indeed, it is shades of gray. But most of those are money-driven debates, not quality-driven. I distinguish TBCs, I don't lump them all together in a single category. TBC is a wide term.

So let's now return to your question...

You're getting drops and inserts. It always comes back to the hardware:

- Which TBCs? Type, brand, model.
- Details on capture cards, and capture systems.

I'm not necessarily asking you for this info, but rather giving you the questions you need to ask, in order to resolve dropped/inserted frames issues. For example, some items, like DVD recorders, are not TBCs, and are a likely source for the errors. It usually happens in-device (silent, not reported), but not always.

Anyway, your understanding of drops/insert is correct thus far, it was just a bit incomplete.

No, you've raised a sleight against my professional character, you don't just gloss it over - you made that assertion on the grounds of no evidence and thought you'd get away with it.

You haven't.

We've noticed you change the subject or accuse others of being 'off topic' as soon as some of your nonsense is pointed out.

I suggest you re-read some of your own past posts, and take those into the context of the thread, and with the other replies it was generating (not just mine, but others). It was anti-TBC. And this question, in this thread, is rooted in TBC usage, type of TBC used.

"sleight against my professional character" --- shall we have 20 paces at dawn? :laugh:

I'm trying to steer the conversation back to drops/insert, audios, TBCs.

I think you've taken "I don't use any of the kit recommended on here" to mean I do not use any quality equipment.

I'm stunned, I've certainly never argued against using them, I'll await evidence. I've told people in the first instance not to get too hung up on explicit differences when they're asking broad questions, but I've never, ever advised against using them.

I will not have somebody who's not got a 'scooby' about what I do, or how I do it telling me I do not use a TBC when I demonstrably have about 20 of them!

Because you've been proved wrong - it's what you usually do.

It's very simple - "Sorry RR, yeah I misunderstood something - I'll edit" rather than doubling-down on something that's clearly not true.

Sure, that seems to be the case. I'm glad to read that you use TBCs. :congrats:

But you still have to watch what's written. Again, the context of the thread turned anti-TBC, and you weren't helping to clarify the necessity of TBCs. This statement was made: "I don't use a TBC of any kind". And your response was "if it is visually pleasing to the person who's watching it, then it's on balance probably a good job." That's just ... no.

British slang has all the cool words. Scooby-doobie-doo! :D

What are the type, brand, model? Again, I'm not necessarily asking you, but it's the question that's needed to troubleshoot drop/insert. Because a TBC isn't just a TBC. Wide term, lots of variables, especially when it comes to interactions with consumer analog videotape sources.

Still - how did you draw from that I do not use a TBC?

I'm still waiting here, you've made the clear accusation that I do not use them for professional work, I have countered, and you're still trying to make out that you're correct.

Seriously, you're wrong here china (as you seem so fond of our parlance) - maybe it's time to have a word and cut out the porkies?

I am? You said you're using TBCs. Excellent. Misunderstanding sorted. The end. Let's move on.

Or let's just end it there.

Because, again, I'm not necessarily interested in threadjacking this topic (any more than it already is, at least). If you want to look deeper at your frame drop/insert issue, to see the root cause, then start a thread for it. We can go over the gear in use, known flaws with any of it. Or perhaps it really is a problem tape, something to be sorted there.

This is uselessunderstanding's thread, so comments should be somewhat germane to his posts.

It's very simple.

"Sorry, that wasn't correct, I could not know that to be true" would have been a more than reasonable reply.

A very simple apology and a retraction, that's all I ask.

You can't just go around making unfounded accusations about my business, then try and 'white knight' for your own posts. It's quite transparent.

Like I say, the smartest thing would be to just withdraw something that you now know not to be true.

No. I suggest you just let it end there.