What is -exactly- the difference between a tv- and a VHS-sig

[JeroenH]

Hi Guys,

I have a bit of a problem, when I capture from a tv signal, everything works great, avg. fps remains at a steady 25.00xxx, hardly any dropped frames. Maybe 2~4 an hour.
But... now I want to capture from a VHS-tape, which is in a bad shape. I think the tape is physically damaged in a few places. When a damaged part plays, VDub starts dropping frames like mad. Why is this? It thought it didn't matter what was IN the picture, as long as there IS a picture? Or is this some sync issue?
After a few of these 'frame-dropping' scenes, audio is badly out of sync

This is my setup:

HP Vectra VE
P2/400
192 Mb
1x 6 Gb IDE (windows + software)
1x 9 Gb U/W SCSI (for captured avis)
Adaptec 2940 U/W SCSI card
BT484 capture card (Pinnacle PCTV Pro)
Creative SB128 sound card

This combo is fast enough to capture 384x288/44.1xSTx16 movies from a tv-signal, but bad VHS-tapes mess thing up, and even good tapes have slightly more dropped frames than movies captured from tv.

I don't think I will ever capture this damaged tape correctly, but I just would like to know the why....

Thanx in advance for any info

Jeroen

[Feslmogh]

There is really not much difference. The reason your tape capture is dropping frames is due to a weak signal from the old tape. If the capture has trouble reading that frame it drops it and waits for a better signal. A newer tape should give better captures for you.
Your signal from the tv is constant enough for the capture board to get good frame captures.

Anyone has a better answer? Did I answer right?

<font size=-1>[ This Message was edited by: Feslmogh on 2001-08-09 15:41:05 ]</font>

[Freddie100]

Seems about right Feslmogh.