Interlaced scanning of interlaced video fields compared with
progressive scanning of noninterlaced video frame.
A.
For interlaced video, entire upper field is drawn to
screen first, from top to bottom, in one pass.
B.
Next,
entire lower field is drawn to screen, from top to bottom, in one
pass.
C.
For noninterlaced video,
entire frame is drawn to screen, from top to bottom, in one pass.