Apple Cinema Tools 4 - Manual (Page 130)

What Is Field Dominance?
The field dominance of a captured clip is determined by the telecine hardware and is
usually not configurable by the user. Video frames are composed of two fields; one field
consists of all the even lines of the video, and the other field consists of all the odd lines.
At the telecine, the two fields are scanned at different times, which means that the film
frame can advance between the time that the first field is scanned and the time that
the second field is scanned.
• When only one field is captured: Field 1 dominance means that only field 1 is captured,
and field 2 dominance means that only field 2 is captured.
• When both fields are captured: Field 1 dominance means that each captured frame is
digitized from two video fields, but field 1 occurs earlier.
Note: With field 1 dominance, the two video fields digitized into each captured frame
should have the same timecode address, because SMPTE timecode is specified as
beginning on field 1. Field 2 dominance, when both fields are captured, means that
field 2 occurs earlier and that the captured frame contains video fields with two different
timecode values.
About A Frames
If your video has window burn, the easiest way to locate an “A” frame is to look at the
key number in the video frame, which typically has a letter after it indicating the frame
type. This letter is called the frame type indicator. A frames include any frame with a frame
type indicator that begins with “A,” including an AA (also known as A1A2), AB (also known
as A2B1), A1, or A2 frame. When you view the video a frame at a time, the frame type
indicator for an A frame shows an “A” and the frame number is solid (not flickering
between two frames).
The frame type indicator
in the window burn tells
you this is an A frame.
130 Chapter 8 Preparing the Source Clips for Editing