interlaced video question for you XV experts

[Billy Biggs]

Benjamin Herrenschmidt (benh at kernel.crashing.org):

> Which field comes first in a frame is different between PAL and NTSC
> if my memory is correct. 

  AFAIK, this is a convention and it depends on how it is being stored,
and has nothing to do with the actual output (you have a 4-field and
8-field sequence for the colour carrier in NTSC and PAL respectively,
but in digital video you don't usually care about that).

  In MPEG-2 there is a flag called "top_field_first" which indicates the
parity for each encoded frame.

  -Billy