Are field A and field B from the same point in time?

[twentworth]

Simple question. Hopefully a simple answer?

When capturing, are the two fields of a standard NTSC video frame taken at the same point in time, or does field B come after field A?

[sitlet]

i believe that field a and field b make up one frame, so they should be at the same point in time. field a is the odd lines, and field b is the even lines. put the two together and you have one frame.

[lordsmurf]

They are weaved together. Not side by side, not at the same time.

And much like pulling a thread out of clothes, not having all the field can destroy the video.

[twentworth]

Is it correct to say that all of field A is recorded before any of field B is recorded?

[lordsmurf]

Is it correct to say that all of field A is recorded before any of field B is recorded?

No, it's not.
Some start at A. Some start at B.
My ATI card starts at A. My DVD recorder starts at B.

[twentworth]

Well, yes, I'm aware that A and B can be reversed. My question really goes to whether one is recorded before the other, or whether a frame is "taken" and then electronically split into the two fields.

[FOO]

If it comes from a camcorder or a television camera
the fields will be from different points in time. If it comes from
a Film transfer , fields will be from a frame and simultaneous.

[twentworth]

If it comes from a camcorder or a television camera the fields will be from different points in time. If it comes from a Film transfer, fields will be from a frame and simultaneous.

Thanks, I think I understand. However, I don't think you're example of a film transfer is entirely correct. Using this as an example: http://www.doom9.org/images/pulldownB.gif note that the second and third video frames do not have identical fields.

[FOO]

You are just being arbitrarily argumentative.
How about a PAL film.
Any idiot knows that pulldown causes mismatched field pairs.

...and the link didn't work

...and "you're" translates to "you are" not "your"

[kitty]

Me thinks they would be 1/60 of a second off for NTSC, 1/50 of a second for PAL.

[FOO]

If the PAL came from film they would be zero off
2 fields are made from a film frame that was captured at one instant.
the fields will be simultaneous in time.