ATI 600 USB audio desync with frame TBC?

[TwistedSystem]

Following on from my previous post about inserted frames, which is now resolved, I'm having some new issues.

I'd just like to thank everyone for their help so far, as I think I'm very close to being able to capture my tapes now!

Here's my workflow again:
Sony CCD-TRV87E (DNR and TBC turned on) out via S-Video into a green AVT-8710 TBC into an ATI 600 USB (drivers obtained from here) into a Windows XP 32bit desktop PC (integral edition). I'm using the VirtualDub version obtained from here, with Huffyuv. OS is running on a 2TB Sata HDD, capturing onto a separate 2TB Sata HDD. All S-Video cables are brand new and decent quality.

I'm having two slighlty different issues. One is that I'm sometimes getting dropped frames. It seems a bit random though, like I'll start a capture and get around 1 dropped frame a minute, but after trying a few times, I suddenly get no dropped frames for the whole capture. Do TBCs need to warm up? Maybe the capacitors in it are starting to go?

Which leads me onto my second issue. Even when I get a capture with zero dropped frames, the audio and video very slowly drift out of sync. My test tape captures for about an hour and by the end of it, the video is about 400ms behind the audio. It starts in sync though, so this isn't a constant offset. In my timing settings, I have it set to not resync the audio/video, which I obviously can switch on, but I don't understand how it's going out of sync given the ATI 600 capture both audio and video. Is this just an expected limitation with these kinds of captures?

[lordsmurf]

Quote:

Originally Posted by TwistedSystem

Even when I get a capture with zero dropped frames, the audio and video very slowly drift out of sync.

You've likely set up VirtualDub incorrectly, and it's simply not reporting drops.

Screen cap you timing settings, post it here.

A lot of really bad newbie-written guides tell you to uncheck boxes that should not ever be unchecked.

[TwistedSystem]

I have seen the guide you're referring to, but I also saw your post saying they should always be left checked, so I haven't disabled drops/inserts in any of my tests.
Here are my timing settings:
Timings.png
I also saw this post of yours which said to disable Force audio clock and I've performed the suggested audio level hack (although I've not really got as far as checking the audio levels properly yet).
I should also point out that I don't have audio playback enabled while capturing, which I know can cause a lot of issues.

I did wonder if VirtualDub was somehow mis-reporting drops though, as I was quite surprised to find I'd suddenly dropped zero frames, but I've read that with a good TBC you should always get zero drops, so I'm not exactly sure...

I'm also using the latest Windows XP integral edition and I've tried to stop as many unnecessary services as possible. The network adapter is also disabled, so I think it's sufficently de-crapified unless there's a specific integral build version that's recommended over the latest one.

[aramkolt]

Personally, I'd at least have the OS/Boot drive on an SSD rather than a HDD, HDD is fine for the separate capture drive though. Technically it should work the way you have it, but the system will be a lot faster with an OS SSD.

Would probably base your settings on this tutorial or at least trying that combo if you haven't already:
https://www.youtube.com/watch?v=pKYNqZdqawc

Looks like where you differ is audio resync where looks like he uses resample audio option instead.

The "right" settings should keep audio in sync, but be aware it might drop and insert frames to keep the audio in sync. An external Frame TBC may do that also to some degree (and we are just unaware as they don't report statistics), but probably is a less likely to drop a frame as they should have a forgiving "frame buffer" since that's basically all a frame TBC is - store a frame or two on a rolling basis in memory and then release them at a digitally-precise rate, first in, first out.

[TwistedSystem]

An SSD is actually a bad choice for Windows XP, as it doesn't have TRIM and is overkill anyway considering that this system is literally only being used for captures.

It may be that this kind of thing is unavoidable without some kind of correction, but I don't want to resort to that until I've exhausted all other possibilties. I'm still a newbie at this, but I'm trying to keep things as close as possible to what's recommended here so I can rule out the obvious things, like not having a TBC (which is the response to most of the posts on here with any kind of dropped frame or sync issues).
Also every capture card/system may require slightly different settings, so I've based my settings on posts which specifically refer to the card I'm using.
If my settings look fine for my workflow, then I need some advice on how to troubleshoot my problem.
I've managed to get two separate captures which both had zero dropped frames and both have, seemingly, the same amout of audio/video desync (about 400ms). Could this be something about the tape I'm using? I've not tried any other tapes yet as I'm trying to resolve all my issues first. I don't want to be messing around like this with the tapes I actually care about.