Dropped frames/sound sync - ATI USB 600
 

Hi all,

I've been noticing increasing frequency of dropped frames - stuttering video - in my captures recently. Is this something that could develop over time as either of my core hardware pieces starts to play up, I wonder? I'm using an ATI USB 600 along with a Panasonic NS-HS950 (which has the TBC turned on) and, separately, a 1T-TBC-DL timebase corrector.

I have played with the Timing settings of VirtualDub like crazy to try to see if that makes a difference. Either the sound gets badly out of sync - and more out of sync as the recording progresses - or there are skipped frames in the original capture, giving my final videos a stuttering appearance.

I have also tried AmaRec, given that some here have said it works well with the ATI USB 600. It captures fine but drops frames all the way - anywhere up to about 25 dropped frames in 10 minutes of video.

I'm confused as hell, really, because I thought that having at least one TBC - in my case two, an internal VHS one *and* an external one - would pretty much eradicate dropped frames and make the sound sync pretty reliable. And yet that doesn't seem to be the case.

Has anyone any suggestions or advice? I'm at my wit's end, really. What I thought was a pretty unbreakable capture workflow is back in tatters, right at its earliest point...

I'll post a couple of examples here shortly so people can see what I mean.

Kind regards to all,

Discy

Hi i do not know if this help but maybe good to see if something in the background messing with the capture

DPC Latency Checker you can download it from here https://www.thesycon.de/eng/latency_check.shtml


maybe check that hard drive is not on PIO mode you can see more here about that https://techlogon.com/how-to-fix-har...k-in-pio-mode/

Want to update on this. I've tried this now in two different machines - one a sacrificial old laptop that has been working fine up to now and the other a modern Dell XPS - and am getting precisely the same result, in both AmaRec and VirtualDub. In the latter, I have the timing settings with all attempts at correction switched off - because that is the recommended configuration for a capture device that combines audio/video, such as the ATI USB 600. But while the sound is in sync at the start of the vid, by 10 mins in it's drifting and by 25 minutes it appears to be the thick end of half a second out of sync.

I'm at my wits end. I have a couple of hundred VHS tapes backed up to convert and right now, I have no reliable way of actually capturing them. Has anyone any idea why the ATI might have suddenly decided to start bleeding sound sync in this way?

Kind regards to all,

Discy

You both didn't mention what Windows you are running. If you read through the many posts on this forum you will find Windows XP is strongly recommended. I have spent many months getting my workflow just right so that VirtualDub has zero jitter and no dropped or inserted frames. Maybe someday I will post my findings. But for now a few (maybe not so obvious) suggestions.

1. Windows XP fixes a lot of issues. In my case very light pops in the audio and all kinds of frustrating things in VirtualDub - although mostly cosmetic with monitoring the video before or during capture.

2. The real fix for your issue may simply be that you can not monitor the audio during capture. If you have "enable audio playback" checked uncheck it. That one caused me all kinds of problems. Seems safe enough. It is not.

3. As a last resort try monitoring nothing during capture. In my case I like the volume meter, the histogram, using compression. Turn them all off and see if you get better results. Specifically Video / No Display (don't use Overlay, don't use Preview).

If you try #2 and #3 then I'm out of ideas but I can tell you for certain both of these made a difference for me on different hardware I've tested. And I've tested a lot of different laptops. Yes, desktops are preferred but I think I finally got a reliable setup. Again, if everything stays working as it seems to be I'll post soon on the technical details.

Okay, so I had a spare old PC which will take an XP installation so I've done that. It's still hit and miss, frankly. My benchmark tape is fine, but others are out of sync - even with the TBC on the Panasonic VHS deck switched on and the additional TBC between it and the ATI switched on.

Is that just how it is? I'm desperate to avoid stuttering dropped frames, so I guess the trade-off for that is that sound will go out of sync and I have to correct it every time in post-production?

Regards to all,

Discy

and... just to confirm when you capture with Virtual Dub you do not have "enable audio playback" unchecked? That was the killer in my case.

What kind of CPU is in the XP system? I found anything newer than a Core 2 Duo (circa 2010) would cause video issues although not audio sync issues.

One last thought, is there any chance you made a setting change in Virtual Dub? A few times I've re-downloaded the 1.9.11 bundle from this forum to be sure I had a completely clean install.

It's an i5-4210M processor.

I do not have audio playback enabled.

Clean install of XP and clean VirtualDub as taken from this very forum. Along with Huffyuv 32-bit, non multithreaded.

XP shouldn't be trying to do Windows Updates but make sure you have the network disconnected just in case.

You also have the Video / No Display (not Overlay or Preview) setting?

I'm running low on ideas although in the many (laptop) configs I tried I found only PRE i3/i5/i7 systems worked 100% reliably. Again, not out of sync audio. Hard to know if you might have an ATI600, TBC or PC problem. I can only go on my limited experience. Sorry.

I have Overlay on. I guess I could try some based on No Display and see if that makes any difference.

Listen, thanks so much for trying to help me.

Regards,

Discy

Easy enough to test. I use an old Sony TV for "watching" as I capture and No Display in VDub just to be safe.

Another variable to eliminate when troubleshooting: capture without audio and see whether you get dropped frames.

Thanks for your help and advice on this. I have spent the thick end of two weeks playing around with various installs, three computers and multiple settings, particularly under timing.

Here's are my conclusions - noted here in case anyone else find its useful in future.

Going back to Windows XP did initially seem to make a difference for me, but it wasn't conclusive.
With that in mind, I have reverted back to Windows 7 32-bit on my sacrificial capture laptop, as before.
I then experimented with No display, Overlay and Preview. These made no difference to me.
I have followed Lord Smurf's advice elsewhere in this forum and installed Catalyst Center. This allows me to preview playback of a video to see if the sound is in sync there.
What *does* appear to make a big difference for me is the choice of compression. I was using Huffyuv median before and the sound was out of sync; now I have switched to Huffyuv left (less compression but faster and less CPU load) and I have now captured four hours from a previously troublesome tape without losing any sync at all.

My timing settings for the ATI USB 600 are as follows:
Drop frames and Insert null frames both DESELECTED.
Resync mode set to DO NOT RESYNC.
Correct video timing for fewer drops/inserts SELECTED.
Everything else DESELECTED.

Don't know if this is something anyone else has encountered but I thought I'd record my findings here in the hope that someone else might find my struggles useful.

Regards to all, and thanks again for your help and advice,

Discy