4.2

Video to be played on traditional NTSC or PAL
televisions is stored using an interlaced frame
rate. Each frame is actually made up of two
half-frames called fields. Each field contains
half the frame lines; the odd (or upper) field
contains lines 1, 3, 5, 7, 9 and so on, and the
even (or lower) field contains lines 2, 4, 6, 8,
10, and so on. When the video is played back,
the TV displays the fields in an alternating
pattern, which creates an effective illusion of
smooth movement. Viewing interlaced video
on a computer screen that displays both fields
simultaneously may reveal a combing effect.
You can deinterlace, or remove the fields from
an interlaced video clip, by converting it to a
interlaced video