Recording from a VCR

[mtamilia]

Hello
I am wondering if someone has same problem as myself.
Capturing video from a VHS VCR results in 50% frame loss and scattering video.

I usually use VDub under XP as a capture application and I capture signals coming from my VCR through the composite link. I use a Pinnacle PCTV Studio card with Conexant chipset. This has an S-video input but my VCR has no S-video out, so I cannot use better than composite.

What surprises me is the fact that if I capture live broadcast from the tuner built in the VCR at 352x288 they are very fine, zero frame loss. If I play and capture a VHS tape, half of the frames are lost. I capture "blind" using HuffyUV, CPU load is seldom over 50%, so it cannot be overloading.

I tried the following:

changed the VCR: no better result
increasing/decreasing capture resolution: no better result
changing capture application: same result, frame losses

It happens with every tape I have, heavily used and old, and brand new.
I think my capture card simply cannot get the low-quality VHS signal in a decent way. But I hear of other people actually successfully capturing and the card I have is a very popular device indeed.

Has someone any suggestion on how to overcome this? or should I simply give up?
Is there any way to "tweak" the chipset for the purpose?

Thanks a lot/Ciao

[AngusMacGyver]

Hello!
It seems you are having problems with any driver. If you can, try to capture under windows 98. I don't know Pinnacle PC TV. But I own a DC10+ that I can't use under xp with virtualdub.

I hope this help you.

Rafael Nunes

[drdy111956]

I am also capping under XP with a BT878 card in VD. Never had any frame drop issues before from any source ( Win 98SE, 650Mh ) although based on the system I would cap blind for 704x480. Now moved under XP 2.4GH , and find that I can capture fine TV , commercial VCR , SP mode VCR recording, but when I try to record from home analogue camcorder tapes, the frame drop rate is 50 %!!!! ( using WIN TV drivers)

[willy_annand]

I too am experienceing the same thing in WinXP using VirtualDub. I can capture with Adobe Premiere 6.5, MGI VideoWave 5, AVI_IO, BUT not with VirtualDub. With the others I get an average of 1 frame dropped every minute or two. With VirtualDub, I get about 30-35% frame dropping.

I have tried to Cap of both my ASUS V7700 deluxe Video card and a Winnov AV PCI capture card.

[hardwork12]

You seem experience with Vitualdub so I doubt this is the problem but let me say it anyway.

Are you sure the FPS capture rate is not at the default of 15 rather than the 29.97 needed for NTSC (not sure for PAL). I made this mistake and got 50% frame loss and it drove me nuts. Once I matched the FPS in capture to the FPS of the source problem gone.

Just thought.

[xed]

This is a very common problem. It is almost certainly due to the fact that you are getting problems with the sync signal recorded on your camcorder's videotape.
The reason why you can capture with zero dropped frames direct from broadcast TV is that broadcast TV contains a nice strong perfectly undistroted vertical blanking interval signal. This is the signal that synchronizes the interlaced frames which scan across your TV screen.
VCRs, however, record this sync signal on magnetic tape, and that creates problems. Tape has dropouts. It shrinks and stretches with age. The sync signal degrades.
As a result the VBI information can be distorted or missing on some video frames. Since your capture card needs this info to know when one interlaced frame has been captured, corruption of this sync information results in dropped frames due to buffer overrun in your capture card.
The only known way to solve this problem is to use a time base corrector.
A TBC will regenerate the corrupted sync signal.
Many digital camcorders have built-in TBCs, so recording toa digital camcorder and capturing that way will work. Or you can use a standalone TBC. They tend to be expensive.
The fact that video capture cards cannot reliably capture from many types of videotape playback devices without a TBC inserted in between thecomposite out of the VCR and the composite input of hte capture card is one of the dirty little secrets of video capturing. Nobody talks about it, but it's part of life.
If you own a newer VCR, it may have a TBC built in (my VCR does). If your camcorder is an analog model, it almost certainly does not have a TBC built in.
That probably explains why you can capture from your VHS VCR but not from your camcorder.
Try a TBC or a fly in the video from your camcorder into a friends digital camcorder and then capture from the digital camcorder by firewire. Those are your only real options.
The fact that you capture fine from your VCR but not your camcorder is the giveaway. It has nothing to do with driver problems. If that were the case, you'd be having dropped frames whatever the source you captured from.

[Heavensent]

I THINK I KNOW WHAT YOUR PROBLEM IS.
YOU ARE CAPTURING AT 29.97 FS
IF YOU TRY 25 FS YOUR PROBLEM WILL GO AWAY.
I DONT KNOW WHY , JUST TRY IT.
I HAVE PCTV PRO AND I HAD A PROBLEM USING 29.97,
WHEN I CAPTURE IN 25 FS - NO PROBLEM AT ALL.

[mtamilia]

Thanks to everybody, I forgot to include some information:
capture is at 25 fps since I want to make a PAL video.
I tried other two capturers but same results happening.
I had same problems under Win2K, not only XP, so it cannot be the driver.

I appreciate all of your help, it seems that Xed has an explanation who's right. I do not have a digital camcorder so I'll see what the cost of getting a TBC is, but usually these things are not cheap at all.

Grazie/Ciao