Sync issues in Virtualdub

[techmot]

Just managed to get a version of Virtualdub working smoothly in capturing from my VHS recorder, however, I noticed there's a noticeable amount of audio of sync and I;ve heard this is a common problem with Virtualdub. Why is this programme so highly recommended as a capture programme when the audio is out of sync and none of the other programmes I've used seem to have this problem?.

[DB83]

You were told, and more than once, for a start to turn off audio preview (ie de-slect 'enable audio playback')


You can also experiment with the 'timing' settings from the Capture menu (these would vary from system to system)


And also re-read all the other suggestions re system resources. Choice of video codec can also be critical.

[Skiller]

Lack of passthrough device or TBC is ought to cause sync issues – even if everything else is setup correctly.
You cannot connect a VCR to an USB capture device and expect it work flawlessly for capturing analog tapes. It just doesn't work and it wastes your time.

[techmot]

Lack of passthrough device or TBC is ought to cause sync issues – even if everything else is setup correctly.
You cannot connect a VCR to an USB capture device and expect it work flawlessly for capturing analog tapes. It just doesn't work and it wastes your time.

If that's the reason then why don't I get this problem with Corel Video Capture?. Aside from it occasionally displaying the copy protected message whenever it feels like it, I dont get the audio out of sync, so why with VDub?. And what other codecs am I expected to use?. The audio isn't out of sync that much just slightly but still noticeable.

[DB83]

I would guess that Corel captures in mpeg2. So that is quite low in CPU resources etc.


But we have not mind-readers. We can only help if we know all the facts. One of which would be the codec you are using. If your CPU is maxing then there are going to be sync issues. You were also told how to help with that.


A TBC is not essential (I do not have one but just an 'unofficial' one aka ADVC300) but it steadies the signal to assist with audio-sync.

[Skiller]

The audio isn't out of sync that much just slightly but still noticeable.

Doesn't matter if you ask me. It's either perfectly in sync or it may be out of sync by hours and is a bad capture anyhow.

If that's the reason then why don't I get this problem with Corel Video Capture?

Lucky coincidence.

A TBC is not essential

Not always, but with a non-Firewire capture device, signal dropouts such as – especially – between recordings on a tape (the "snow") are going to cause massive frame inserts and thus make VirtualDub having to compensate by trying to re-sync the audio on the fly. You can actually see this if you enable the Timing Graph in VD and watch it while capturing. It takes minutes for it to catch up again and during this time the audio is typically off by some hundreds of milliseconds. This is exactly the kind of sync issue any passthrough device or TBC does aid and there is no way around it when using a USB capture device (unless maybe you manage to capture in segments and capture only perfectly stable signals).
Firewire devices such as the ADVC family or Sony MiniDV or Digital8 camcorders with analog-in are immune to this; the audio will always be in sync.

[lordsmurf]

Firewire devices such as the ADVC family or Sony MiniDV or Digital8 camcorders with analog-in are immune to this; the audio will always be in sync.

Not true.
It can, and does, just as easily lose sync.
There's nothing special about Firewire. It's just a comm port/method like USB, AGP, PCI, etc.

[Skiller]

Cannot confirm. I digitized an entire collection of Hi8 with my Sony MiniDV in passthrough (analog -> DV/Firewire), just straight from the analog Hi8 camcorder (no TBC) into the Sony – no sync issues even after the most damaged parts of a tape you can imagine. There was nothing that could bring audio sync out of whack.

It's not because of Firewire itself, yes, it's not magic, but because these devices are tied to the DV standard which mandates small packages of video and audio (interleaving) there is much less chance of things getting out of sync.

[techmot]

The audio isn't out of sync that much just slightly but still noticeable.

Doesn't matter if you ask me. It's either perfectly in sync or it may be out of sync by hours and is a bad capture anyhow.

If that's the reason then why don't I get this problem with Corel Video Capture?

Lucky coincidence.

A TBC is not essential

Not always, but with a non-Firewire capture device, signal dropouts such as – especially – between recordings on a tape (the "snow") are going to cause massive frame inserts and thus make VirtualDub having to compensate by trying to re-sync the audio on the fly. You can actually see this if you enable the Timing Graph in VD and watch it while capturing. It takes minutes for it to catch up again and during this time the audio is typically off by some hundreds of milliseconds. This is exactly the kind of sync issue any passthrough device or TBC does aid and there is no way around it when using a USB capture device (unless maybe you manage to capture in segments and capture only perfectly stable signals).
Firewire devices such as the ADVC family or Sony MiniDV or Digital8 camcorders with analog-in are immune to this; the audio will always be in sync.

I suppose you're right about Corel having a low CPU usage when capturing in MPEG2 rather than in avi, I guess that would affect the syncing. To be honest I dont have a big problem with MPEG2 capture as I can't see much difference in quality; for just analogue VHS capturing it's good enough for me, the only issue with Corel is the annoying copy protected message which will appear for no reason at random times, even when the image isn't jumping (which usually what causes this to happen, or so I thought). I left a tape capturing for about an hour and 40 mins only to come back and find Corel had stopped the recording with the "this tape is copy protected" message, and yet the tape is just a recording from a TV broadcast, no copy protection on it. I'm guessing any commercial paid software like that will have this macrovision system on it.

As for codecs in Vdub which will eliminate the sync problem, what do you recommend?. I'm guessing they need to be installed first?.

[lollo]

but because these devices are tied to the DV standard which mandates small packages of video and audio (interleaving) there is much less chance of things getting out of sync.

I do not think is because that, because avi files by nature have the same architecture.

https://virtualdub.org/blog2/entry_025.html:
Audio and video data are broken into blocks and mixed together; each video frame has its own chunk, but audio data is organized in small packets. This is the "interleaved" part of the file.

However, I ignore what the size of the single audio/video packet in avi and in dv spec. Do you know it?

Back to the original question, in Windows 10 sometimes VirtualDub has synch issues with certain cards. If the asynch cause is not a high number of dropped frames, AmarecTV can solve.

DVD-R pass-thorugh is not always requested capturing from tapes in good conditions and using a S-VHS VCR with lineTBC. In my case I almost never use it, not needed and not transparent, but that's my case. About asynch aspects, it only helps when there are gaps between recorded segments, as noted by Skiller, but is not solving an asynch issue for a continuous stable signal: for example I experimented an asynch issue with Windows 10, Hauppauge USB-Live 2 and VirtualDub. ES-15 did not solve it, AmarecTV did it. YMMV!

[Skiller]

As for codecs in Vdub which will eliminate the sync problem, what do you recommend?. I'm guessing they need to be installed first?.

HuffYUV is recommended and for audio don't use any codec at all (choose uncompressed PCM).

I do not think is because that, because avi files by nature have the same architecture.

Right, AVI inherently does that – but it's the capture software that puts the data into an AVI container after receiving the data via USB. The raw data is not transferred via USB in this exact packaged manner that the resulting AVI has, unlike DV/Firewire. In other words: it's too late to have an effect on sync.

However, I ignore what the size of the single audio/video packet in avi and in dv spec. Do you know it?

No, never cared about it. Seems to make not much of a difference.


I don't have any experience with Windows 10 for capturing. I capture on XP, so indeed, YMMV.

[DB83]

As for codecs in Vdub which will eliminate the sync problem, what do you recommend?. I'm guessing they need to be installed first?.

This has also been covered in your other topics. But it would equally help if you answered the questions asked and not just the same ones in multiple topics.


Now we have two additional topics the content of which could have been covered in your original topic. All this achieves is confusion.

[lollo]

Right, AVI inherently does that – but it's the capture software that puts the data into an AVI container after receiving the data via USB. The raw data is not transferred via USB in this exact packaged manner that the resulting AVI has, unlike DV/Firewire. In other words: it's too late to have an effect on sync.

Good point! In this case the video and audio stream in the capture cards we use are digitized and kept separate at the output of the A/D chip and then "aligned" by the capture software, while in the DV devices the output of the A/D conversion, whatever chipset is used, already provide an "aligned" stream, thus synchronous. I will do some research on that, it is very likely the reason why in DV captures are (almost) always in synch, while other devices are not; lordsmurf will disagree with us about this

I don't have any experience with Windows 10 for capturing. I capture on XP, so indeed, YMMV.

Yes, but usage of DVD-R passthorugh effect is not depending on OS, and is not blindly mandatory. However, as we said, our mileage may vary!

To the OP: is difficult to follow you across several posts and with the small info you give. We'll be happy to help you, but please follow DB83 and dellsam34 recommendations!

[techmot]

Right, AVI inherently does that – but it's the capture software that puts the data into an AVI container after receiving the data via USB. The raw data is not transferred via USB in this exact packaged manner that the resulting AVI has, unlike DV/Firewire. In other words: it's too late to have an effect on sync.

Good point! In this case the video and audio stream in the capture cards we use are digitized and kept separate at the output of the A/D chip and then "aligned" by the capture software, while in the DV devices the output of the A/D conversion, whatever chipset is used, already provide an "aligned" stream, thus synchronous. I will do some research on that, it is very likely the reason why in DV captures are (almost) always in synch, while other devices are not; lordsmurf will disagree with us about this

I don't have any experience with Windows 10 for capturing. I capture on XP, so indeed, YMMV.

Yes, but usage of DVD-R passthorugh effect is not depending on OS, and is not blindly mandatory. However, as we said, our mileage may vary!

To the OP: is difficult to follow you across several posts and with the small info you give. We'll be happy to help you, but please follow DB83 and dellsam34 recommendations!

I know my repeated posts are a real pain but I'm struggling to understand the issues I'm having with capturing, far too technical for a layman such as myself to understand the ins and outs of video compression and syncing issues, I would just like to capture my videos as easily as possible with the limitations I've got, but like I said I'm constantly encountering so many problems with different capture programmes; if it's not copy protected messages popping up for no reason it's some other problem. As I've probably said before my best bet is to buy a decent spec PC with a proper capture card installed and not the crappy USB capture device I'm using.

[lollo]

with a proper capture card installed and not the crappy USB capture device I'm using

Don't know what you are using, but together with a high end S-VHS VCR with lineTBC or a good VCR with a DVD-R pass-thrugh, a recommended capture card is the first step. All the rest comes after...

[DB83]

We do not expect you to understand the complexities of video compression etc.


Imagine you went to the doctor, told him you had a headache and expected an instant diagnosis.


So all we ask is basic information. If you do not know how to determine that information you just ask and not ignore the question.

[Skiller]

Good point! In this case the video and audio stream in the capture cards we use are digitized and kept separate at the output of the A/D chip and then "aligned" by the capture software, while in the DV devices the output of the A/D conversion, whatever chipset is used, already provide an "aligned" stream, thus synchronous.

Yes, I think so too. My experience does confirm this.

As I've probably said before my best bet is to buy a decent spec PC with a proper capture card installed and not the crappy USB capture device I'm using.

A PC is more versatile than a laptop for capturing but this is not a task that requires a beefy PC. Heck, you could capture perfectly fine with a 20 year old Pentium III on Windows XP as long as the hard drive is reasonably sized.

[techmot]

Good point! In this case the video and audio stream in the capture cards we use are digitized and kept separate at the output of the A/D chip and then "aligned" by the capture software, while in the DV devices the output of the A/D conversion, whatever chipset is used, already provide an "aligned" stream, thus synchronous.

Yes, I think so too. My experience does confirm this.

As I've probably said before my best bet is to buy a decent spec PC with a proper capture card installed and not the crappy USB capture device I'm using.

A PC is more versatile than a laptop for capturing but this is not a task that requires a beefy PC. Heck, you could capture perfectly fine with a 20 year old Pentium III on Windows XP as long as the hard drive is reasonably sized.

I still have my old desktop PC running on Windows XP which I used to have a video capture card installed, though I think I uninstalled it and removed it from the back years ago and it probably won't work now; without checking I can't remember what make it was, maybe an Happauge. Very rarely did any video capturing on it, though the PC is very slow, and even booting up takes ages. I've been thinking of getting rid and selling it, whether it's worth anything I've no idea as I doubt anyone uses XP anymore. The Dell CRT monitor I had it hooked up to after the original monitor it came with packed in is over 20 years old and still works perfectly. Been using the same monitor for the past few years connected to my other (now broken) laptop via the VGA connection, a rare thing to see on a laptop nowadays I would imagine. The desktop I have isn't a Pentium processor, I think it's just a Duron.

[Skiller]

Very rarely did any video capturing on it, though the PC is very slow, and even booting up takes ages.

Wiping the OS and installing XP on a fresh partition should help a lot with this. It's because over the years of everyday use the OS accumulates too much garbage which slows it down.
Actually that old PC may be suitable for capturing. Do you know what speed that Duron processor runs at? If it's above 1000 MHz that's good enough. 512 MB of RAM would be ideal (256 MB is about the minimum with XP).
If the motherboard has an AGP port for the GPU (most likely has) you could consider getting an ATI All-in-Wonder which is an excellent capture card (even Lordsmurf recommends it).

If that Dell CRT you are talking about is a Sony copy (Trinitron), then it is among the best PC CRTs ever made. I'm sitting here writing this on my trusty Dell P991 CRT.

[techmot]

Very rarely did any video capturing on it, though the PC is very slow, and even booting up takes ages.

Wiping the OS and installing XP on a fresh partition should help a lot with this. It's because over the years of everyday use the OS accumulates too much garbage which slows it down.
Actually that old PC may be suitable for capturing. Do you know what speed that Duron processor runs at? If it's above 1000 MHz that's good enough. 512 MB of RAM would be ideal (256 MB is about the minimum with XP).
If the motherboard has an AGP port for the GPU (most likely has) you could consider getting an ATI All-in-Wonder which is an excellent capture card (even Lordsmurf recommends it).

If that Dell CRT you are talking about is a Sony copy (Trinitron), then it is among the best PC CRTs ever made. I'm sitting here writing this on my trusty Dell P991 CRT.

I've just had a go at booting the old desk top and it's not as slow as I previously thought, probably because I've removed most of the programmes from it aside from the required ones. The Dell monitor it's linked up to is a D1028LR, manufactured in November 1998. No idea if it's a Sony Trinitron model as it doesn't say, but to be still working after over 20 years is remarkable, but likely because much of its early life prior to me getting it from a guy I used to know it was rarely used in the place he worked at which had about 20 other identical machines in a computer suite. I suppose if something doesn't get used much than the life expectancy of it will probably last abit longer, and being a Dell monitor probably has helped.

The tower isn't Dell though having been built by a local computer shop in about 2003 using a mainboard, and over the years I've added a CD and DVD writer to it plus it once had a fresh fan installed by someone I used to know who had a knack for computers. The spec is:
Windows XP Home Edition version 2
Service Pack 3

Computer:
AMD Duron processor
1.29GHz 368 MB RAM

NTFS: used space: 19.0GB Free space: 95.5GB

[Skiller]

You absolutely could capture with this looking at the specs.

Free space: 95.5GB ist not great but enough for about 2.5 hours of HuffYUV capture. And if that PC is conneced it to your LAN you could transfer the raw captures to a modern machine for further processing/encoding and free up space for the next capture (it's not going to be fast with, probably, a 100 MBit LAN interface but it's pretty convenient).
Or you could add a used IDE HDD for only a few bucks.

[Brad]

I would expect frame drops capturing to that old 120GB system drive. But with a secondary hard drive, those specs are better than what I used to capture with in the early 2000s.

[techmot]

I would expect frame drops capturing to that old 120GB system drive. But with a secondary hard drive, those specs are better than what I used to capture with in the early 2000s.

How do I install a codec into Virtualdub? do I copy the file into the Vdub folder and then open up the compressions settings?. The codec that's available and set as default is YU2, and the audio is set to uncompressed PCM. As for sync issues, but would it help to capture to an external HDD?.

I think an easy solution of getting round the audio sync issue is to import the captured file into a good editing programme (like Adobe Premiere), unlink the audio and video in the timeline and manually line up the audio with the video so it matches. I just did this with a 30 min video I captured in Vdub, saved as an AVI to avoid anymore loss and the outputted file audio matched up. Not much of a hassle if you know how to use the programmes, and I'm sure there's probably more simple ways of re-syncing the audio. Didn't take too long to encoded it either.

[DB83]

Again !!!!!! (And I am losing patience with this) for the LAST time explain what codec you are using.


Codecs do not need to be explicitly 'imported' in to vdub. If you have downloaded and followed the download instructions that codec is automatically made available to vdub. Windows takes care of the actual linkage.


The compression settings show what codecs are installed and available. No installed codecs = pure uncompressed video (which is equally true if you did not select another codec from the list that you should see)


The exception to that is that vdub2 includes codecs fired by ffpeg as opposed to stand-alone FULL/'installed' codecs.


And you were already asked to provide a mediainfo report (text mode) of the video - not here but elsewhere - which you have conveniently ignored. So how are we to assist -diagnose- when we simply do not have all the facts before us.

[Skiller]

I'm with DB83 on this. If you want help, you need to answer the questions we ask and not ignore them.

I think an easy solution of getting round the audio sync issue is to import the captured file into a good editing programme (like Adobe Premiere), unlink the audio and video in the timeline and manually line up the audio with the video so it matches.

If that works for you but to me that seems like beating a dead horse.

[dellsam34]

I think an easy solution of getting round the audio sync issue is to import the captured file into a good editing programme (like Adobe Premiere), unlink the audio and video in the timeline and manually line up the audio with the video so it matches. I just did this with a 30 min video I captured in Vdub, saved as an AVI to avoid anymore loss and the outputted file audio matched up. Not much of a hassle if you know how to use the programmes, and I'm sure there's probably more simple ways of re-syncing the audio. Didn't take too long to encoded it either.

If you are suggesting your own solutions then why bother posting threads that you don't answer to, For a very problematic tape? yes, a way of capture? no.

[techmot]

I'm with DB83 on this. If you want help, you need to answer the questions we ask and not ignore them.

I think an easy solution of getting round the audio sync issue is to import the captured file into a good editing programme (like Adobe Premiere), unlink the audio and video in the timeline and manually line up the audio with the video so it matches.

If that works for you but to me that seems like beating a dead horse.

Then what other solution do you have?. Is there a programme that can re-sync the audio?.

[dellsam34]

Yes, and it has been suggested numerous times in your posts:

1- Disable audio preview in vdub
2- Use a DVD recorder as a pass-through

[lordsmurf]

Mix of accurate and wrong info in this thread...

A TBC is not essential

Not correct whatsoever.

(I do not have one but just an 'unofficial' one aka ADVC300)

If you think a TBC does nothing, but your only experience is a ADVC-300, I'm not surprised. The ADVC-300 "TBC" is an inept laughable POS that does minimal to nothing. You need to see an actual TBC in action, both line and frame, not a low quality DV box.

for audio don't use any codec at all (choose uncompressed PCM).

Technically that is a codec, simply one already installed and available in VirtualDub. All audio and video must have a codec, even "uncompressed" (audio and video) is a codec with options (YUY2, 48kHz, etc)

Lack of passthrough device or TBC is ought to cause sync issues – even if everything else is setup correctly.
You cannot connect a VCR to an USB capture device and expect it work flawlessly for capturing analog tapes. It just doesn't work and it wastes your time.

Correct.

It's not because of Firewire itself, yes, it's not magic, but because these devices are tied to the DV standard which mandates small packages of video and audio (interleaving) there is much less chance of things getting out of sync.

The DV standard (DV25 consumer DV) isn't magic. Those devices can, and do, drop frames. The interleaving has nothing to do with video frames being lost, with audio being retained (ie, sync issues).

Don't know what you are using, but together with a high end S-VHS VCR with lineTBC or a good VCR with a DVD-R pass-thrugh, a recommended capture card is the first step. All the rest comes after...

There really isn't a "first step". All are important for quality, or capturing at all. I'd rather have a JVC S-VHS with line TBC, and a DataVideo/Cypress frame TBC, and an Easycap (yuck, Easycrap, barf). As opposed to a crummy old VCR, no TBC, and the best ATI AIW capture card. Because the latter will be pure problems. Both of those situations would suck, however, either the Easycap, or the non-TBC/JVC.

As I've probably said before my best bet is to buy a decent spec PC with a proper capture card installed and not the crappy USB capture device I'm using.

That won't fix much, if anything. The issue is the video hardware, not the computer.

As for codecs in Vdub which will eliminate the sync problem, what do you recommend?.

Codecs will not correct bad incoming signal. But a good codec won't cause the I/O and CPU to drag. Use Huffyuv.

I don't have any experience with Windows 10 for capturing.

It's pretty terrible, and very limiting.

1- Disable audio preview in vdub

Some cards are fine in audio preview.
Some actually require audio preview.
Some just need settings tweaks (usually timing settings) to work fine.
Others are a pure no-go, no preview ever.

[dellsam34]

His poblems are with audio preview enabled (regardless whether it is the cause or not), he never confirmed he disabled it in none of his multiple threads to eliminate that possibility.