Audio sync Encoding with VS7

[Grenge]

I have been capturing some video from video tape to my PC via a Winfast TV 2000XP Deluxe TV card. Then I open the files in Video Studio 7 to trim and re-encode at a lower bitrate to have the files at the right size ready for when I burn them to a DVD in DVD Movie Factory 2.5.

Occasionally when I am re encoding the files 1 in every 10-15 will go out of sync, but the original file from the capture isn't out of sync, and the only way I can fix it is to re-capture the files and re-encode again. If I try to re-encode the original file a second time, it goes out of sync again. It seems to go out of sync in a specific spot (ie a slight pop in the audio and it is out of sync) but doesn't go any further out of sync.
Another strange thing that happened is I once captured 1.5 hours of video, then I split the files into 3 separate 30 min files with MPEG2VCR and encoded them with VS7. The first file went out of sync but the second two didn't.
Could something on the tape be causing this or just some glitch in the PC at the time of capture.

[rcb]

Most likely your rig is dropping a chunk of frames while capturing.

Many things can cause such, but look for background tasks (tsr's, anti-virus) interference, multi-tasking, instant messaging, etc.

Monitor your CPU load during capture.. if it's constanlty being loaded over 50-60%, doesn't take much of another simultaneous demand to cause a momentary choke.

[Grenge]

I usually shut down my virus and firewall before I capture. I will check other programs running in the background as well.

Do you think I should unplug all USB devices connected as well? I have a scanner, printer and web cam connected (although the webcam is new and wasn't connected when the problem first arose)