VirtualDub video significantly shorter than audio?
 

Hi there!

New to the forums and coming with you to a bit of an oddity that I am currently in and I'm a bit confused on why this happened or what I should do next.

I just finally made a switch to trying to use VirtualDub instead of my older method after doing some research.

What I currently have now is a Panasonic NV-SV1 VCR on S-Video/RCA that's going through a Pinnacle 710 USB.

I've never used VirtualDub prior to this so I spent a long time figuring out how to set it up/get it working on my Win 10 machine which was a headache in itself but I got it working to a point where I could capture a few test clips with relative success.

So I figured I would give it a full run today by recording one of my 6 hour blanks to give it a true test to see how things come along. Throughout the day as I was watching it along with doing work, I could see it capturing just fine with 0 frames dropped or no signs of errors as far as I could tell.

After the 6 hours came to an end, I hit "Esc" on the capture and was ready to see how it came out in the actual file! It was then that I felt like I got punched in the gut as I saw the audio was crazily out of sync and I wasn't sure why. Figuring this maybe was just my media player acting up as it sometimes doesn't like huge files being played, I tried another and alas it was still there.

Curiously, I brought it back into VirtualDub to check the file information, and that is where I was met with this information (see attached photo for visual evidence):
Video
Duration:5 h 55 min
Audio
Duration:6 h 10 min (this is the correct length of the recording and what was showed when I ended the capture)

Needless to say I was deflated realizing that the entire tape is offsync by nearly 15 min and I'll have to try it again.

But, I'm not what I did wrong or if there's anything I'm doing wrong, which is why I have come here for help. If anyone has any ideas of what I can try to get this fixed so I don't have to go through this again, I would appreciate it.

Some more info:

• I am on a Windows 10 machine. 22H2 to be exact and with Windows Update turned off so no chance of moving to 11.
• My computer has a high level Ryzen CPU, 64GB of Ram, and I was recording onto a 7200 RPM HDD that had 1.5 TB free so I'd like to think spec wise I'm safe from it being that but let me know if I'm wrong.
• I am using the VirtualDub 1.9.11 download from here, but I am using I believe a newer HuffYUV that I got from Github
• Relooking at the test files, it also looked like they were desynced, but in a much more shorter distance (12-13ms difference). My guess is though becuase they were short files it didn't have the time to desync so it just compounded from the longer recording.
• The only other thing besides the settings I can think that could cause an issue is that the Pinnacle USB is being connected to my computer via a USB Hub rather than directly on the machine. I didn't think it would be an issue because my older setup using a Hauppauge PVR and recording via M2TS was done through that USB Hub and never had an issue.

Never uncheck the top two boxes in the VirtualDub timing settings. All that accomplishes is to effectively disable dropped frames reporting, so you have no idea what is happening. It reported "0", but only because reporting was essentially disabled. There's a lot of bad guides out there.

Re-capture some video, with those properly checked, and let's see what the drop/inserts look like.

Lack of frame TBC is surely the root cause here, but let's go ahead and troubleshoot the entire path if you want. (But you can skip to the end, that's going to be it. TBC needed. No, line TBC in a VCR is not frame TBC. And no, a DVD recorder is not a frame TBC.)

If we assume that's the correct 710-USB -- though it probably isn't -- then those can be "more resilient" to frame loss. But if the tapes are bad -- and understand that bad-signal tapes can still "look fine" (the non-visual matter, no the visual) -- the nothing is that resilient. Frame TBC required.

Hi there smurf! Pleasure to meet you and let me add in some additional stuff if that's okay! I'm still learning a lot of this stuff so I apologize if I get any of this wrong.

Settings
Thanks for letting me know about that! I think the guide I read was on videohelp along with some here and I guessed I crossed some patterns. I'll make sure to get those turned back on! Besides that, was there anything else that you saw in my settings that was blatantly wrong or off?

I'll get those checked.

The pinnacle
Is there a wrong 710 one to get? I had gotten that one based on some recommendations I had seen from you in other posts. The one I have for reference looks like this one:
https://www.ebay.com/itm/204966412166

The TBC
Thank you for clearing that up a bit! I did want to note that this machine does have a TBC (and maybe a frame one?) I got the recommendation from one of these old deter posts

https://www.digitalfaq.com/forum/mar...shed-vcrs.html

And i know you're not the biggest fan of ebay, but I did find this one through a seller that had a lot of detailed pictures and talked about what he did internally to make sure it works.
https://www.ebay.com/itm/204898405546

But if it comes down to that, I may have to start saving up for a tbc then.

I am curious though and maybe you can help me understand because I Def want to learn.

The prior setup I had was a Samsung VR-357 (I know dvd/vhs bad but best I could get for free at the time while I saved up) connected to a Happauage PVR and using Happauage Capture to make m2ts files. I had done a lot of those with not one real desync issue. Is it just because of something inside that machine or just because of the way that capture program worked to get the footage versus virtualdub?

Thanks in advance!!

https://www.digitalfaq.com/forum/vid...-tape-set.html

I would completely disable the wifi adapters.

Windows 10 is the bottleneck. The specs don’t really matter for capture. It’s a single core task. It will help you in hybrid during post though.

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

https://www.digitalfaq.com/forum/vid...ure-stops.html

https://www.digitalfaq.com/forum/vid...time-base.html

Thanks Gary for the response and feedback as well! Going to take a look at these tomorrow and big thanks for sharing all of these! I really appreciate the response and will also reply back if I have any additional questions :)

Welcome. :)

Yes, there are "right" (correct) and "wrong" (incorrect) cards. Not just the 710, or just Pinnacle, but many (sadly most) other cards makers as well. The model # is left the same for SKU (sales) reasons, even if the internals are different (sometimes vastly different).

So is your exact card right or wrong? No idea. The seller didn't know either. Blind leading blind.

Imagine wanting a sporty racing car. You settle on a Dodge Charger Hellcat. But you just buy "a Dodge" from eBay, site unseen (ie, the internal 710 board is not shown). When it arrives, you learn that you bought an Astro van.

An external frame TBC is not an internal line TBC. No more than a dog is a cat, or a cat is a dog.

It's really not about being "a fan" of eBay, as I enjoyed buying/selling there (toys/toons/games/comics, not video gear) immensely in the 90s into 00s. But things have changed since then. For video gear, it's a wasteland of lies and idiocy, where 80-90%+ of videeo gear is garbage (and that is not an exaggeration, but literally a measured % from multiple tests from multiple people, with sample sizes of up to 100 units). But even a broken clock is correct twice, so good buys happen. Just not often. This site has more horror/failure stories than success stories.

Yep. It's just a tool for a task. I saved up to buy a pressure washer and a steam cleaner, because we need to detail the car. (Same tools also useful to clean the sidewalks of algae, and the bathtub tile grout.) This really isn't any different. Tools for tasks, tools for projects. If you buy a quality tool, you can buy it, use it, then resell it. If you buy crap, it's yours forever, sunk cost, wasted money.

TBCs aren't sexy tech toys, but boring tools, like microwave and washing machines. You buy it because you need it, no other reason.

Video can work in two different ways.

The method suggested for analog video ingest/capture is essentially a graceful Olympic runner in a race, constantly moving at a steady clip, until the race is over. This method errs on the side of accuracy, to extract all video and audio, every detail available. Now, this is not "overkill", but rather "attention to detail". You are, after all, dealing with decades-old media that is pretty mediocre to poor (when at its best) compared to modern HD/4K/8K video. Not just the resolution, but the bit depth, color retention, etc. So you want the best possible extraction, without loosing more data. Because we've all seen how bad lossy "potato quality" video is, desyned video, etc..

The method used to broadcast/stream video is a klutz, constantly tripping over his own feet. But he always gets up, keeps moving. Sometimes the person behind him kicks him in the ass to keep him moving forward, hurry it up, keep up the pace. This method of video just stumbles over boogers, embeds it into the quality. It usually doesn't "lose sync" because it simply drops audio samples when video frames are lost. Though other methods exist to gloss over errors, and hope nobody notices.

"Not noticing" these problems is easy in a tiny preview window, or a phone -- but not at all on modern 40/50/60/70/80" HDTVs.

It's essentially the difference between program streams, and transport streams. Not entirely, but this does come into play. .mt2s is a transport files, usually MPEG.

That second method is also used by many DVD recorders, because those were designed for the ignorant masses. Same for many of the low-end video cards, namely the "PVR" styled cards. When you start to measure frame-by-frame accuracy, view audio waveforms, you see the "magic" of how these low-end videos "work". (And "work" is arguable. It may not lose sync, but it still looks like crap in most cases.)

It's about quality/integrity, vs. so-called "good enough" (translation: not good) video.

Thanks for the warm welcome!


Ah okay that makes sense! Is there anything I can do to test and see if it's good or bad just from the outside appearance or would I have to really dig in and tear it apart? I'm assuming the latter, but might as well ask!


So, after tinkering with a BUNCH of settings in the capture window (see picture) I FINALLY got it to actually give me an output that is not desynced or delayed from what I can tell which I was glad to see.

Only real negative I saw is that there's a fair share of insert frames happening which I'm not too jazzed about but I'm assuming at this point only a TBC will fix that or the tape was just also off since there were certain parts of the tape where inserted frames happened often and then some sections where it was rare to see it tick up. Shared the results of the hour recording as well here picture wise.

The only dropped frame I got was upon starting the capture which leads into another question that maybe you can help me out with. Is there anyway to have the capture start before I hit play on the device or something similar?

I've noticed when I press F6 to start a capture, I usually have to wait like a few seconds as it shows nothing on the screen, then a picture does show up but its a bit choppy in the FPS department, and then once it finally gets to the correct framerate on the output, then the recording starts. I'm wondering if there's a setting or anything I can do to correct that.


Yeah, I'll chalk that up to me misinforming myself while reading the TBC FAQ. I just misunderstood it at first and after re-reading this morning and a bit last night, it makes a lot more sense to me now :)


Fair enough! I can understand the woes of getting a bad batch of equipment from eBay (dealing with a sound card return as we speak haha), but I usually always try to get one from someone who at least seems reputable or provides enough evidence that I feel confident that I know what they're doing.


Tis' true. Only real qualm is that the TBCs that are worth getting is at least $1000 if not more. I can understand the need for it, but it's a hard pill to swallow and will still take some time to start saving up for because I sadly don't have the money tree I was promised nor a stack of just TBC Rainy Day cash haha! I am curious, in the meantime, would it be worth trying to use my Samsung players as a passthru? There's a chance this is a silly idea, but figured if it DOES have at least a mid TBC for now while I save up, it's better than NO TBC.


Really appreciate the words here and the understanding of it all and how these recordings and transfers work. I've done a little bit of video work here and there but nowhere in depth as others have here and its been a joy to sit and learn about these things since I was mostly just skating by and was okay with my PVR output. But, I'm ready to take it to the next level!

Thanks again in advance :D

Some sellers are traps for new people. https://www.digitalfaq.com/forum/vid...-ebay-vcr.html

One piece you kind of left off is how long the tape actually was. My guess is the tape length matched the audio length. The video length being shorter suggests a lot of dropped frames. As an example, if you had a 10 minute VHS and half the frames were dropped, when you go to play back the captured frames at the appropriate frame rate, you'll be out of frames to play in 5 minutes. Audio doesn't really ever get dropped because lack of audio is just silence and periods of silence are not skipped over during playback like dropped frames are. You could unplug your audio cables from the VCR after 1 minute of capture while continuing to capture audio and video, then plug the audio cables back in for the last minute of capture and the audio should still be in sync by the end of the video.

Depending on the frame TBC, some will output either the last frame of good video if you unplug the incoming video signal or many will just output black frames. I haven't done a bunch of testing, but I can say that the For.A FA-310 just outputs black burst when incoming video is disconnected. The capture card would see that as black video frames and it would continue to capture those. So with an appropriate TBC, you should be able to disconnect the incoming video signal whenever you want and it will continue to feed something to your capture card to preserve the "silence" or "lack of signal" of there being frame dropouts or even complete video loss. This is what makes it so that the audio never gets out of sync with the video.

You'll likely still run into sync issues if for some reason that frames dropped aren't followed up with an equal number of frames inserted in virtual dub to compensate. With a good TBC, you shouldn't really have any frame drops at all though.

Oops my apologies! I did make a note of that within the original post, but it was in a parentheses after the audio length and I should've been more clear on that. The length of the first recording I did was 6 hours and 10 minutes and you are correct that the audio length was the correct length of the recording and the video was 15 minutes shorter than it was supposed to be.

Ah okay good to know! I think the 0 I ended up seeing was due to having some timing settings turned off to help me identify them. But also weirdly enough after turning some of them on, I would still only get maybe 1 dropped frame but yet the timing was still wildly off with the video getting lost. Wasn't until I think the 8th test I ran this morning that I finally got a pair of settings that didn't do that.

Ooh interesting! I'll have to keep that in mind for sure and thanks for that insight! Just goes to show how much I still need to learn heh, but that's good for later reference should I run into this desync again. I'm going to try another full scan tomorrow with the settings I posted about earlier that did work as intended and hope for the best while I continue to save up for a good TBC.

Thanks for this link as well and a good read. Definitely something I'll need to be more wary of down the line.