field ident

[DrP]

Bit away from desktop video, but are there any analogue video wizzards reading? I have a question for you!

I need to know for sure if the sync serrations for the odd field has the extra serration or is it the even field.

[Brian Ellis]

Sorry, don't understand your question. Could you please rephrase it?

If you have a vertical line moving across the screen, each field has 288 (PAL) or 240 (NTSC) vertical pixels, so that you have the same number of pixels displaced (or serrations) whether the line is moving to the left or right.

For most (not all) analogue captures, use upper field first. For DV, use lower filed first.

[DrP]

Analogue video indicates which field is which by adding an extra serration (short transitions at the hsync rate) in vsync. I can't remember if field 1 is signalled by the extra serration or if its field 2. A fair bit of googling turns up lots of info about it, but not anything definite.