Dropped frames high when capturing VHS but ok with TV

[chrisgw3]

I'm trying to capture from VHS using a Win TV/GO,VirtualDub and HuffyUV. I have my VCR connected to the composite in on the TV card.
In VirtualDub I have the source set to 'Composite In', so I am always using the signal from the VCR (one benefit of this is that I can get Stereo rather than just mono from the card's tuner).
With the VCR in stop mode (i.e. just the TV signal being output from the VCR to capture card) I can capture at 352x288 PAL at 25fps with no dropped frames. Everything fine.
However, when I play the VCR and capture from the tape, the dropped frames increases to about 30%. In both cases CPU usage is lowish (25%). I have defragged my drive and killed all background tasks.
If I reduce the capture resolution to 320x240 then all is ok, no dropped frames.
Can anyone explain? I guess it's something to do with the signal quality. I believe VHS resolution maxes out at about 250 lines.
I' like to capture at 352x288 as I want to burn to VCD.


Thanks in anticipation,


Chris

[deadpac]

I have a similar situation right now. (Almost, but not quite)

I can capture from Digi Cable over OTA with an Antenna hooked up to the coaxial input on my TV Tuner Card at any resolution, anywhere from 352x240 to 720x480 [haven't tested the limits on my cap resolution just yet, 720x480 is playing it safe] [Cocky because of the Koolance Water Rig OC'ing an p4 1.6gz running at 2.4ghz ($80 American for a 2.4ghz 8) )]

Anyways basically I can capture at any resolution with the Antenna/Cable input on my TV Tuner card, so no problem here.

But whenever I try to capture from the Composite input on my card from a vcr [tried a 4head, 6head (yes 6head) and S-VHS) I drop A LOT of frames at resolutions such as 320x240 and 352x240 and even odd dimensions such as 60x80 and I still drop like 80% of frames. But after a lot of trial and error I found out that capturing from the composite input on my tuner card requires a high resolution of 680x480 or greater as the minimum resolution. Can you believe that a minimum resolution that most people can't even achieve as their max. [Please don't ring in about your rig,box,comp,etc.... I can beat you with any of my OC'd rigs or Dualies, BRING IT 3Koolance Water Towers, 4EXTREME-AIR cooled rigs with fan size minimum of 92mm and 120mm [minimum of 5 fans in the air cooled rigs and 3 in the H2O rigs]

"It's freakin Quasimoto in my ear, and you laugh" -Billy Bob Thorton in Bandits

This was all in WinXP pro.

When I set up a Windows 98 and Windows 2000 partitions same computer, I found that I was able to capture an any resolution from either the coax or composite [antenna and vcr]

What OS are you running, try running Windows 98 [tv-tuner card driver friendly OS] and if that doesn't work try Windows 2000 [not so frienldy driver OS]

Yes, installing OS's would be a pain in the arse for something as simple as capturing video, but hey that's how I solved my problem. Maybe something as simple as upgrading your drivers might do the trick for either your TV tuner or Direct Media drivers or even your Video-card, but when all else fails try the o'le OS switch trick, wich isn't all that unusual in these parts [desktop video enthusiasts].

"AHHHH, FOR THE LOVE OF GOD, does no one else hear that ringing,................Tinnitus, which is what they call it, which is what I've got" -Billy Bob from Bandits

[jamba]

You guessed it right - it's the signal quality of the quality of the VHS tape itself. I suggest you do the following:

1) Clean the VHS heads.
2) Clean the RCA connectors on both the VHS player as well as the cable itself.

However, if your tape is really bad then you cannot really expect a capture without dropping frames.

Good luck and hope this helps.

[kwag]

Go here:
http://btwincap.sourceforge.net

For no more dropped frames!

[chrisgw3]

Many thanks for the replies.

BTW deadpac, I'm running WinME and don't intend to change - quite happy with captures from other sources.

One thing I didn't mention was that captures were also ok at 352x288 with analogue input from a miniDV camcorder.... so yes, it all points to the quality - although when playing the tape it looks fine on a 14inch tv..... TVs are more forgiving I suppose.

Can anyone offer an explanation (to a relative newbie) why the input quality matters - I mean, if you encode a poor audio source to MP3, all the noise (crackles, pops, hiss) gets encoded too. Why does video capture not just capture all the imperfections at 25fps rather than dropping frames? Any why will it capture poor quality source at 320x240 at 25fps but not at 352x288?

Is it possible to deduce anything about the signal quality from those 'jitter' statistics in VDub?

Kwag - I did briefly try the btwincap driver but it didn't make any difference to the VHS tape capture. I uninstalled it because I believe the Hauppauge WinTV2000 app requires a Vfw driver. Is there any way round this - to use the btwincap WDM driver in VirtualDub and still have the WinTV2000 app working?

So many new things to learn!....Thanks all,

Chris

[Stile]

Please, try capture with resolution 384x284 and let me know the result. I also have many dropped frames on 352x288 and when I capture with 384x284 (I can't have 384x288) I have no droped frames. I have Hauppauge WinTV PCI and capture is from VHS.

[chrisgw3]

Thanks, Stile, I'll try that and post the outcome.

[chrisgw3]

Brilliant....... 384x288 works like a dream ..... no dropped frames. I wouldn't have imagined that increasing the res would result in fewer dropped frames! Curious as to why that should be.... can anyone explain?

Many thanks Stile.

Chris.