Video-a ss is t-sy stem – ARRI ARRIFLEX 416 User Manual
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From the first film frame, two video fields are derived, the
second film frame, three video fields are derived, from the
next film frame, two video fields and so on.
The White Line flag works as follows:
Every time, the video field corresponds to a new film frame,
the letter will change either from A to B or B to A and the
number will be set to 1. As long as no new film frame is
taken, the video fields are counted, beginning from 1.
Consequently A2 is the first repetition of A1. B2 would be
the first repetition of B1, B3 would be the second
repetition. On every A1 or B1, the selected video line will
get set to video signal white, indicating that only these
video frames correlate one-to-one to film frames. The
duplicated video fields are not marked.
In spite of the fact that the name Pull-Down comes from
the working practice in the NTSC systems, where on a
telecine the film is running on 23.976 fps and gets
converted to 29.97 fps, the definition of Pull-Down
information on the IVS can also be applied to PAL and to
film speeds other than 23.976 fps.
Note:
The insertion of White Line flags is only done,
when timecode is actually recorded on film. If
there is no timecode recording, for example
because the camera is not running on a time-
code speed, no White Line flag is sent out.
Note:
The White Line has priority over VITC lines. If
the same line is selected for White Line as well
as for VITC, White Line will appear.
Video-A
ss
is
t-Sy
stem