DigiDesign SYNC HD, Manual

Page: 59 / 103

Chapter 4: Using SYNC HD 53
VITC Generation/Regeneration
When you use the SYNC HD to regenerate or
generate VITC, you’ll be inserting VITC into an
existing video signal. The input is derived ac-
cording to the following rule.
VITC Video Source Rule
Since the SYNC HD has two video inputs
(“Video In” and “Video Ref In”), the following
rule describes which of these two signals VITC is
applied to.
‹
If the Positional Reference is set to Generate
and the Clock Reference is set to either of the
two video inputs, then VITC will be applied to
the video signal at the Video Ref In connector
and fed to the Video Out connector.
‹
Under all other combinations of Positional
Reference and Clock Reference, VITC will be ap-
plied to the video signal at the Video In connec-
tor and fed to the Video Out connector.
In addition, the SYNC HD will not insert new
VITC while reading VITC from an external
source. This is a safety feature to prevent the loss
of existing VITC in the video stream. VITC is
never inserted when the Positional Reference is
set to VITC or Auto Switch LTC/VITC.
Example Video Input Configuration
One common situation is transferring video
from a source VTR (or a nonlinear video editing
system) to a destination VTR (or a nonlinear
video editing system). The video source signal is
connected to one of the SYNC HD video input
connectors according to the VITC Video Source
rule.
The SYNC HD Video Out signal is connected to
the destination device. The SYNC HD is then
able to stripe the second VTR’s videotape with
VITC. (At the same time, you might also want to
insert a window burn. See “Window Dub Dis-
play Options” on page 58.)
To prevent destruction of the original VITC
code, the SYNC HD will not re-apply (regener-
ate) VITC onto the same video stream from
which it is reading VITC.
LTC
If you want to use LTC as a positional
source, do not select Auto Switch LTC/VITC.
External
In order for the SYNC HD to regenerate
VITC based on an external positional reference,
you’ll need to select both a clock reference and a
positional reference.
To regenerate VITC based on an external
positional reference from Pro Tools:
1
Ensure that the SYNC HD is connected in-line
with a video source and video destination.
2
Ensure that VITC Insertion Enabled is selected
in the Synchronization page of the Peripherals
dialog.
3
If necessary, choose the line pair from the
VITC Generate Lines pop-up menu in the in the
Synchronization page of the Peripherals dialog.
4
In the SYNC Setup section of the Session Setup
window, select valid clock and positional refer-
ences, and ensure that you have selected the ap-
propriate video format (NTSC or PAL,
depending on your project). For instructions,
see “Video Format/System” on page 63.
Unlike LTC, the SYNC HD can regenerate
VITC with both forward and reverse time
code addresses.