Avid Technology Pro Tools SYNC HD, Manual

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Pro Tools | SYNC HD Guide 32
LTC can also be generated as an interpolation of
Absolute code. This is how timecode DAT ma-
chines, DA-88s, and many digital VTRs work.
LTC is delivered to the SYNC HD as a series of
audio pulses, regardless of how it is stored or gen-
erated.
LTC can be used simultaneously as a positional
reference and a clock reference.
To set LTC as the SYNC HD positional reference
from Pro Tools:

In the
SYNC Setup
section of the Session Setup
window, choose
LTC
from the
Positional Refer-
ence
pop-up menu.
To set LTC as the SYNC HD positional reference
using the front panel controls:

Press the Positional Reference switch to select
LTC.
Make sure you select the appropriate clock refer-
ence, sample rate, frame rate, and freewheel dura-
tion. Also make sure the LTC signal is routed prop-
erly to the SYNC HD LTC In connector.
Freewheel Duration
Freewheel duration (timecode freewheel) config-
ures the SYNC HD for the maximum number of
frames (from 4 to 40 frames, in increments of 4) it
should continue generating if timecode drops out
or is otherwise interrupted. Freewheel settings are
ignored when the SYNC HD is in Internal/Gener-
ate mode.
Example of Timecode Freewheel
In a 30 fps Pro Tools session, if Freewheel Dura-
tion/Timecode Freewheel is 28 frames, the
SYNC HD will continue to generate until either
the incoming timecode signal is restored, or until
28 frames elapse, whichever occurs first.
To set the freewheel duration using Pro Tools:

In the
Timecode Settings
section of the Session
Setup window, enter a number of frames for
timecode
Freewheel
.
SYNC HD accepts Freewheel duration values
from 4 to 40 frames, in increments of 4 frames, but
Pro Tools allows duration values from 1 to 120
frames (for MTC readers). If you enter a Free-
wheel duration value lower than 4, the SYNC HD
will automatically set to 4; if you enter a Freewheel
value greater than 40, the SYNC HD will automat-
ically set to 40.
To set the freewheel duration using the front panel
controls:
1
Press Set, and use the Up and Down switches to
display Freewheel Length (“FrEE LEn”).
2
Press Set to display freewheel duration choices.
3
Press the Up or Down switches to scroll through
available choices (from “4 Fr” or four frames, to
“40 Fr” or 40 frames).
4
Press Set.
VITC and Positional Reference
Because VITC is timecode information that is em-
bedded as part of the video signal, VITC can be
read when the VTR is paused or crawling slowly.
When working with Pro Tools, this means that
VITC can be used for Auto-Spotting clips to par-
ticular video frames.
The Positional Reference setting you choose
remains set, session to session, until it is
changed again.