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OVERVIEW
bypassed, and the next frame number is substituted by the generator.
If the number of consecutive jam bypass errors exceeds 5, the last
valid reader time is jammed into the generator again. In the absence
of valid reader data within the last 5 frames, the generator continues to
increment normally until valid reader code resumes. At this time it will
be re-jammed to the reader, thus repairing large drop outs on the
reader tape.
EDGE NUMBER: The manufacturers of motion picture film stock print a frame
identifying number along the edge of the film, during the
manufacturing process.
NUMBERS, occur at one foot, or half foot intervals, hence they have
also become known as footage numbers. The film frames between
the edge numbers are identified by interpolation from one edge
number to the next.
Traditionally, these numbers have been only human-readable. The
task of properly identifying the correct number is somewhat tedious,
and prone to error, so much care must be taken in establishing the
reference frame's number.
KEYKODE: Machine readable bar-coded edge numbers introduced by Eastman
Kodak in 1988, and subsequently standardized for all film
manufacturers by the Society of Motion Picture and Television
Engineers. AGFA refers to it as BAR Code, and FUJI as MR Code.
For the sake of consistency throughout this manual we shall refer to it
as KeyKode.
KEY INFO: The part of the KeyKode number that does not fit into the user bits of
time code.
manufacturer ID, the film emulsion letter, and the first four prefix digits.
When using the 4025's "full KeyKode" modes, the complete KeyKode
information is encoded into a secondary VITC line pair.
PREFIX: The edge numbers are usually composed of a group of digits that remain
constant throughout the length of the roll, and a count number, which
increments every foot or half foot. The constant numbers, are referred
to as the prefix. The count numbers are referred to as the footage
number.
2/3 PULLDOWN: Film is typically viewed at 24 frames per second (fps) while
NTSC video is viewed at 30 fps. To compensate for this difference in
the frame rates, telecines use a 2/3 pulldown. Since each video frame
is comprised of two video fields, video is viewed at 60 fields per
second. Telecines can transfer 24 film frames to 60 video fields (30
video frames). The resulting ratio is 24:60 or 2:5, which means 2 film
frames every 5 video fields.
frames is transferred to 2 video fields, the following film frame is
transferred to 3 video fields, and so on.
GEN LOCK: In order to ensure that the timecode to video relationship is fixed,
according to SMPTE/EBU specifications, a video reference must be
supplied to the 4025 Film Footage Encoder. Normally, the gen lock
signal is the program video out from the telecine, onto which the
vertical interval time code (VITC) is being applied. When VITC is not
being used, the gen lock signal is usually the colour black system
reference to which the telecine is itself genlocked.
Model 4025 Film Footage Encoder Manual
These numbers, also known as KEY
The Key Info data normally consists of the film
The 2/3 implies that one of the film
The gen lock
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