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Re: TLC Editing with drop frame time code



At 10:30 PM 3/17/97 -0800, Claudius Neal wrote:
>I have a session that requires the A frames at the edit with drop frame
>time code. The hole punch on the film is on the A frame and the TLC is
>editing in A frame mode. What I'm finding is that the sequence on the
>tape will not reference to a 00 or 05 frame consistantly. I'm told that
>its possible to make the TLC edit on a 00 or 05 and keep the 2/3
>sequence. Is this possible and if so how can I do it?


The TLC A Frame Mode was designed by a group of vendors and facilities with
specific rules to simplify the transfer process.  These rules include
non-drop frame code and only using timecode values ending in "0" or "5" for
the SMPTE A frames.  This worked well since starting with timecode value of
"00:00:00:00", all A frames happen every 5 video frames.  In drop-frame,
however, this is only valid until the first minute where two frames are
dropped from the number list.  In the TLC A Frame mode, the TLC will
correctly mark A frames in drop-frame timecode but the numbers will not
always be "0" and "5".  It is basically every 5 frames starting with frame
"0".  The A frame mode was not designed nor intended to be used with
drop-frame timecode.  While it is sometimes possible to "trick" the A Frame
mode to do this depending upon your application, it might be better to use
one of the other TLC modes to get the desired end result.

You may, however, accomplish what you want in a variety of ways depending
upon what TLC version and software version you are using.  If you are
transferring the entire roll and wish to use drop frame timecode starting
at 1;00;00;00, for instance, simply use the "2:3" mode in the TLC2 and mark
the SYNC POINT at this frame.  If you are using a "Classic" TLC system, you
may write a simple macro which simulates a 2:3 sync point at the same
timecode (drop or non-drop).  This macro only has a few keystrokes and
produces the same results as the GANG MARK SYNC POINT, except the first
film frame is a SMPTE A instead of a SMPTE B.

Set the desired film and VTR Edit In Points as you would for your first
edit (the film punch at 1;00;00;00 for example).  Perform the following
keystrokes instead of "Gang Mark Sync Point":

	FILM-A
	TRIM IN
	-+1 <ENTER>		; use the minus "-" and "+" keys here to trim a negative film
frame.
	VTR-A
	TRIM IN
	-1.1 <ENTER>		; note the ".1" uses the FIELD key.
				; Perform this for all recorders in the macro
	GANG MARK SYNC POINT
				; marks the actual 3:2 sync point here
	GANG TRIM IN
	+1 <ENTER>		; sets you back to your original Edit In Point

At this point you have a SMPTE A frame defined at the desired edit in
point.  This will work in both drop and non-drop timecode.  If you are
using drop-frame timecode and pass the first dropped minute, your SMPTE A
frames will not lie on "0" or "5" frame values.  This system will work
well, however, if transferring the entire reel and not stopping.  Even if
you do stop, you may perform pick up edits using the GANG keys, but may not
happen on the A frames.

If you are trying to do "selects" in drop-frame and every take must happen
on a "0" or "5", you could repeat the above macro for each edit.  You will
probably be "breaking" the SMPTE sequence at the edit point.  This may or
may not be a problem for the end user, but be aware of this behavior.

Remember the "0" and "5" timecode numbering scheme was designed to simplify
the process.  If transferring entire reels while only logging the first
event for each reel, it should not be necessary to use the TLC A frame
mode.  Using the above method you should be able to edit any film frame to
any timecode regardless of type and still maintain the A Frame at the punch.

Regards, Gary Adams, TLC Product Manager, da Vinci Systems



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