Is the field order sometimes reversed at the start of a capture?

[arnie.d]

I capture my old analoge home movies with a Canopus ADVC55. The DV avis it produces are always BFF (as I understand is the standard for DV). I'm assuming the video is interlaced. So I'm wondering, when I start a capture and the first field that enters the capture device is a TF, will the field order be reversed to produce a BFF avi? Or does the capture device start capturing at the first BF that enter the device?

[JohnnyMalaria]

No, it isn't possible.

DV doesn't record separate fields in the conventional way. It merely compresses the entire frame as a whole. There is a flag in the metadata that specifies what kind of field order is used. The only way the field order could get reversed is if that single bit that specifies it was corrupt. It's highly unlikely, though, since the flag appears multiple times during one frame.

Do you get this problem recording through the camera or from an external source (e.g., a VHS recorder) or both?

[arnie.d]

I don't have this problem as far as I know. Someone else on a different forum with a PDI Deluxe card and JVC 9911U S-VHS wrote:

When I do multiple captures of the same scene, the field order seems to be random initiated (<- my guess anyway). To explain: in viewing the resulting supposed almost identical captures in VirtualDub, half of my captures of the scene will have cut x be a clean "progressive" style cut from one shot to the other while the other half of the captures of the same scene will have that same cut interlaced. (I also notice that one style is always a scanline lower than the other.) I basically understand what is happening I think. At each starting of the capturing, the capture card is kicking in on either the top field or the bottom at its start, resulting in two different looking types of captures in the end, right? But I ask...
a) Is one of the two results more "correct" than the other? (I would assume that the one shifted down a scanline might be the "wrong" one if there is such a thing)
b) Is there a way to have all the captures turn out the same in this regard, a setting in VDub or something? (I am wanting to do to multiple captures and carry out the "averaging" technique with Avisynth, but as it is I have to throw out half my captures because averaging both of these together will create a mess as I want to keep things interlaced).

So I was wondering if that was possible for my DV device also, since it is standard BFF.