Weird problem I'm encountering and I'd like to see if anyone has any thoughts.

First my setup:

I've got a JVC S-VHS VCR outputting either live CATV or taped video video analog audio and video cables to a Canopus ADVC-100. The Canopus, of course, coverts to firewire and connects to PC. PC is a P4 2.4 GHz, 512 DDR400 RAM, with 120 GB 7200RPM 8 MB cache drive (used only for A/V capture), running WinXP Pro (all patched, etc).

The project:

Recording ~3 hr baseball games to S-VHS. Select clips and highlights from game and dump them individually to PC as DV-AVI. Ditch the rest of the game and reuse tape (maybe once a week?).

The problem:

I'm getting a couple inconsistent jitter effects and audio "popping" and noise when capturing anything from tape. Specifically the video "jumps" every now and then just like it's losing, say, 2-10 frames. There is also this jitter sort of thing where the little score bar gizmo (that appears at the top or bottom of sporting events you see on tv) is sort of shifting up and down by a pixel or two regularly. As far as the audio is concerned, the sound level sounds fine, but there's this static/noise/popping that happens frequently. The video and audio problems are inconsistent. Some times they occur, sometimes they do not. If I dump a segment of the video to DV-AVI and it has problems, then do it again, the problems will be similar but not the exact same.

What I tried:

I've captured in Premiere, WinXP's Movie Maker, and some trial versions of other capturing software, such as PowerVCR. The video/audio problems occur when capturing to any of these and, just as before, are present but inconcsistent. None of the apps report any drops frames, etc, etc. I've also tried different cables, as well as swapping out the Canopus for a borrowed Dazzle DV bridge device, and get the same problems.

Okay, so I'm thinking dropped frames, perhaps a problem with the computer, etc. But...here's the kicker for all that:

Stop the tape and just capture live CATV and it's flawless. No jitter, no noise, etc. I've tested this multiple times and get the same result on different devices and capturing apps. Also, I should mention that the tape in general looks/sounds fine on a tv. Still though, it's got to be something to do with this tape or VCR. I've tried different tapes and get the same result. The list of possible problems seems very short, but tough to overcome.

My only alternative to this (money being the limitin factor, of course), is to just capture every game live straight to the computer. I would rather not do this, though, as it's obviously going to make massive, cumbersome video files, eat lots of harddrive space, and makes the computer unusable for ~3 hours during every game.

I'm really stuck here. Anyone have any thoughts?