Best Virtualdub capture timing options with TBC?

[denfin]

My workflow is:

JVC HR S8600->Datavideo 1000 TBC->Tevion ATI 600 USB

What may exactly be the best options in Virtualdub in the "Capture Timing options" window to get the right audio sync? Sorry if this probably have been asked before but I still feel a bit confused what settings I should use, these are the settings I have right now:

settings.png

Anything I should change?

And also, do I need to plug in the audio through the TBC for the sync? Or can I hook it up directly to the USB capture device and bypass the TBC? Will there be any difference hooking it up directly VS through the TBC? Just wondering cus will make my setup less cluttered if I can just use one RCA stereo audio cable instead of two.

[Gary34]

https://www.digitalfaq.com/forum/vid...-settings.html

The audio needs to go from your VCR to your capture card. Never through your TBC. Only when using a pannasonic dmr es 15 or some kind of frame sync should you run your audio through it instead running it from your VCR to your card.

[denfin]

Okay thanks! I hook the audio up directly then! And guess I have the settings right looking at that post there, except that "force audio clock" thing so I unckecked that. But hm, I still seem to have some sync issues, like just a constant sync issue, not cus of dropped frames and such, I did capture a tape with Virtualdub, and then I captured the same tape with my JVC DVD recorder, and imported the two captures with a video editing program, and I can see the audio captured with Virtual dub has like a 5 frame delay comprared to the JVC DVD capture, and it's a bit noticable when just playing the Virtualdub file and looking at it too, the mouth movements don't sync up for example, any ideas what I may do wrong?

[Gary34]

We had a thread that was kind of similar a little while ago. https://www.digitalfaq.com/forum/vid...g-default.html

[denfin]

Hm wait still a bit unsure what I need to do? sorry! I use Windows 7 btw if that helps.

[Gary34]

On the forum go to guides, then digital video guides, then capture AVI with an ATI All-In-Womder card, then ATI hacks from our forum, then click on if you’re using the ATI 600 series card and they might have some information for you.

[denfin]

Don't seem to find the exact issue I got, cus seems to be consistent and already 5 frames out of sync right at the start. But hm yeah, I try to copy a complete 4 hour tape now and see if it goes more badly out of sync at the end or something or if it is consistent and about 5 frames wrong all the time.

[Gary34]

I just thought about it and this is an ATI 600 USB clone. It may not be the same as far as some of the hacks since it’s a clone and not a rebadge. I was trying to help but I’m kind of new myself so maybe it would be a good idea to wait for someone else’s input on this one. I’m not sure on this one.

[Gary34]

You would be more likely to get help with this if the title was Vdub timing settings Tevion (ATI 600 clone) or something like that. Then add some tags. It would also be easier for other people having the same issue to find later.

[denfin]

Aha yeah, but not sure I can see an option to edit the title? But I copied a whole 4 hour tape now to test, and it is like about 5 frames audio delay through the whole tape it seems, cus I had a look near the end and it was the same delay, so it's consistent at least. Guess I can just move the audio 5 frames afterwards, but yeah just kinda annoying to have to do an extra step. And also, what does the Sync "Current error" thing mean at the bottom? You can see in the screenshot, it goes up and down a little bit all the time I noticed, is that normal? I did have 0 frame drop and inserts on the whole 4 hour tape at least, so the TBC is doing it's thing tho it seems. sync current error.jpg

[lordsmurf]

+/- few ms is normal. Nothing is perfect 0, not even the audio as stored on the tape.

[denfin]

Okay thanks, good to know that at least!

[malfc]

Thank you for asking this - I have the same issue and I would love to know some other way to make everything align more smoothly.

My solution is not practical: After rendering to mp4 with trim settings you're happy with, drop the file into Audacity (after enabling the FFmpeg import/export library). In Audacity, apply some noise reduction or any other audio corrections before saving it as a FLAC file. Then, I have to render the project again in VirtualDub2 with the same settings except select "Audio from another file" and choose the FLAC that was just created. As long as the trim or length of the audio file are unaltered, it should have the same length as before.

Then (the part I absolutely hate the most) go into the project code (I use avisynth code) or whatever controls the trim settings and adjust the first frame so that the rest of the video aligns with the audio. Usually I have to cut out the first 3-5 frames, save, and drop the project file it into VirtualDub2. I have to watch it in a few different spots until the sync looks about the same as the original (or in many cases, closer than the original). I'm always guessing with this and usually have to re-adjust the first frame and re-save the project file several times before I'm happy with the sync. I honestly hate it and imo it's the single most tedious thing about this process - especially since I have not yet figured out a way to accurately recognize how many frames separate the video/audio. (Toggling between the images of the flac audio and the original audio makes no difference because its sync was wrong to begin with.)

And once that's done "save video" again with the same file name replacing the previous mp4.

[traal]

Avisynth lets you DelayAudio with negative numbers, so once you measure the audio delay of your TBC, you can add one line into your scripts. How to measure it:

1. From the VCR, connect one audio channel to the TBC and then from the TBC to the capture card.
2. Connect the other channel directly to the capture card.
3. Capture a short scene that contains a sharp noise (to assist in aligning the channels).
4. Export the audio to Audacity.
5. Measure the time difference of that sharp noise between the two channels.
6. Reconnect both channels directly into the capture card.
7. Add the DelayAudio line into your Avisynth scripts after AviSource() but before Trim().

Then just export the audio as normal, do your corrections (I always normalize the audio) and then remux the audio back into the video (I use MkvToolNix GUI).

[malfc]

When the TBC has no audio input/output I think you just have to guess.

It also doesn't account for different tapes often sync'ing in their own special ways but I guess that's a different issue.

I have a feeling there's a more efficient way to handle this issue than the solution I posted earlier so feel free to help me on this.

I also have a follow-up issue:

I use these exact timing settings except I don't select "Force audio clock when playback is enabled." And my most recent dub acted very differently from ones I've done in the past. It's a 6-hour tape - once it's done, I noticed the sync is still fluctuating throughout. It starts very slightly delayed - about 0.1 seconds, moves into an aligned sync in the 2nd hour, then hastened between 0.1 and 0.2 seconds until the final hour of the tape. Then it's correctly aligned again for about 10 minutes before getting delayed more and more throughout the last hour - 0.2 seconds, 0.5 seconds, 0.7 seconds - by the end of the tape, the delay exceeds a full second. This has never happened before and I'm not sure what I did wrong.

My understanding is that the audio should be adjusted throughout so that the timing stays aligned. Is there another reason why this would happen?

[malfc]

what does the Sync "Current error" thing mean at the bottom?

I noticed this a day or 2 ago. I'm somewhat guessing, but I think when you select "sync audio to video by resampling the audio to a faster or slower rate" - the "sync" box says how much virtualdub has slowed down or sped up the audio in that section. In a tape I dubbed yesterday, it looked like the current error number was farther from zero in the first 45 seconds and during abrupt transitions (hitting the pause button during taping or between different broadcasts) when it's more likely to display noise. And eventually it adjusts back to zero.

Add the DelayAudio line into your Avisynth scripts after AviSource() but before Trim().
This helped a lot. thank you!

[lordsmurf]

Current error = any offset, any desync of audio from video. You really will not notice issues until about 100-200ms, so 1-5ms if literally nothing to worry about. You need to understand that the audio and video on the analog videotape is not perfect either.

The problem with speeding up/down audio is that dropped frames are glossed over. The audio sssslllooooowwwwwsss ddddoooowwwwn -- R SDS P (or speeds up) --- without any indication. You make more problems than just letting it drop or have tiny ms offset. Not worth it.

There are a lot of VirtualDub "options" that should not be user-accessible.

[ThumperStrauss]

I was getting the same symptom as OP but with SVHS > ES15 > AIW9600xt + TurtleBeach sound card. The cause was that i sent audio directly to sound card bypassing ES15 pass through. The audio got to the computer faster than the video and right from the start. Sounds like your issue. I don’t have TBC-1000. I read the comments that one shouldn’t pass audio through TBC1000. I wonder why that is the advice. Because it seems to me that the problem you are describing would be solved if the audio and video follow the same route into your capture card.

As for solutions to this problem, I would drop the AVI file into virtual dub and then use the audio settings to delay the audio. It always breaks my brain to try to figure out how much to adjust the audio backwards or forwards a little bit or a lot in order to get everything synchronized. I recommend that you watch the adjusted video in VLC and MPC to make sure that they are both showing the same level of synchronization as I think I have had issues where it looked good on one, but not on the other and then my brain truly exploded and I may have even wept.

[Gary34]

Quote:

As for solutions to this problem, I would drop the AVI file into virtual dub and then use the audio settings to delay the audio.

His delay is unnoticeable. https://www.digitalfaq.com/forum/video-capture/12810-tbc-1000-channel.html
It’s different than an ES15. https://www.digitalfaq.com/forum/vcr-repair/13348-panasonic-dmr-es10.html

[aramkolt]

This is not probably an ideal way of fixing your situation, but just to throw out an idea - there are "audio delay" hardware devices that will add a fixed amount of delay to your audio that you could use. Most TBCs will induce at least 2 frames of delay, but usually the delay isn't enough to cause noticeable audio sync issues. This only will work if your audio is ahead of the video and if it's a fixed amount ahead of the video throughout the tape.

If the video slowly gets more and more ahead of the video, I would think that's more of an indication of cumulative dropped frames.

I did like the idea that Traal put forward about actually measuring how much video delay the TBC is adding - I think the easiest way to do that would be two CRTs showing the signal on either side of the TBC (input and output). For the input side, ideally you'd use a source with two outputs so that one can go to a CRT and one can go to the TBC. The other CRT would be connected to the output of the TBC. Then you'd just play something with quick scene transitions or go from playing a dark scene and press "stop" to bring up the blue screen while filming both CRT's in the same video frame using something like a smartphone. You can then look back at the video taken of both CRTs and subtract how much quicker the input side was to display the blue screen than the output side was and that's the delay time that the TBC is adding. Your audio should be ahead by that much.

Main reason to use a hardware audio delay would be for conversion processes that you want to do in one step, or if you are very annoyed by previewing the raw file with those sync issues.