VHS capture with ADVC100 - Locked or unlocked audio

[mustardman]

My VHS sources are from video camera, and hence are quite unstable with regard to the real frame rate. I use PAL, so the ideal frame rate would be 25fps, but I imagine that would vary probably 1/2 a fps as the camera is wobbled about.

I want to minimise frame drops, and I have noted (using locked audio) that the occasional frame is dropped for no reason. That is, the signal is good, and a re-capture of the "bad" section will always get the missing frame. I can not be sure, but I am pretty certain this happens with longer captures, and not with short ones.

I assume that the ADVC drops (or even repeats) a frame so that the variable incoming frame rate remains locked to the audio.

So... would un-locked audio (even though the sync may drift out) not cause these dropped/repeated frames??? Anyone had any experience with this??

PS: I have not seen any frame duplicates, only dropped frames.

[echooff]

I also capture from a vhs camera and never experience frame drops unless I try to multitask while capturing. Perhaps you have something running in the background.

[Swan]

Originally posted by mustardman
So... would un-locked audio (even though the sync may drift out) not cause these dropped/repeated frames??? Anyone had any experience with this??


Tha ADVC-100 seems to have problems with some tapes, I've noticed too. I've read on Canopus's forums that the problem may be related to the audio signal as well as the video, i.e. the ADVC demands both a stable video *and* stable audio signal. A TV is much "sloppier", so a tape that looks OK on the TV coming from the VCR, may actually have unstable sync signals and this shows up when you capture it with the ADVC, which is picky.

I've experienced dropped frames a few times when capturing from VCR and it's been on retail tapes, not tapes I've recorded myself. Setting the dip switch to Unlocked Audio helped, and audio and video stayed in sync. The recording I did this on was 45 minutes long, so I think that proves that although the audio and video is not locked, they're still synchronized inside the ADVC when the analog to digital conversion is made and so, the data stream from the ADVC is in sync, always.

I personally planned to capture a lot of VHS, so I solved the VHS-occasional-dropping-frame-problem by buying a Time Base Corrector, namely a Datavideo TBC-1000. Using that device, I can set the ADVC to Locked Audio, even on those problematic tapes.

/Maria