The TLC was designed originally for Newt Bellis and Mark Miller of Unitel
Video,
who contributed ideas. Unitel’s Paul Chapman, a Rank Cintel expert, contributed
a lot of design insight and hands-on help…and cheerfully fixed Unitel’s
Rank
MK-IIIC each time we blew it up.
The "generation loss" of signal quality of analog recorders was the original
impetus for TLC. Accurate and repeatable edit control during the telecine
transfer
process avoided the then-existing requirement to re-edit transferred material.
By
the mid-80’s, digital transports dominated telecine bays; TLC remained
desirable
due to time savings and creative latitude which by then had come to be
expected
in telecine operations.
Originally based on the CPM operating system with application code written
entirely in the Forth programming language, and using five 4 MHz 8-bit
Z-80
CPUs, each with 4K bytes RAM and 32K bytes of fixed code storage in EPROM.
8-inch floppies stored session settings and the most recent (single!) edit.
TLC could
synchronize up to two Rank Cintel or Bosch telecine transports via custom
control
modifications, and up to four VTRs or ATRs (typically a Nagra) under serial
Sony/SMPTE RS-422 "9-pin" control. For mix effects, TLC coordinated a Grass
Valley 100 switcher. NTSC transfers were field accurate, with correct 3:2
pulldown handling at the edit points; PAL and variable film speeds were
supported. TLC computed necessary audio pitch correction ratios.
In the mid-80’s, CPM was retired and the TLC was modified to run under
a
proprietary real-time kernel, again written in Forth. The Z-80’s were replaced
by
Hitachi’s "super Z-80" chip-the "fast" HD-64180 (8 MHz), supporting deeper
RAM
(32K) and EPROM (512K) space. 5.25" floppies replaced the 8", and it became
possible to save the entire edit decision list to diskette for the first
time.
From 1981 until 1994, over 200 TLC systems were installed, predominantly
in
Hollywood, New York, London, and Sydney. During this period, Jim Lindelien
designed and promulgated the FLEx (Film Log EDL exchange) protocol, to
address industry demand for 3:2/field-accurate edit decision information
captured
by the TLC, and useful to other "downstream" editorial devices and processes.
Support for real-time capture and editing using Kodak’s Keycode and Aaton’s
film
edge timecode technologies were added soon after. TLC capture of Keycode
edge
numbers and their relationship to video time code facilitated automatic
conformation of negative cutting, to match the edited master videotape.
Avid,
Evertz, and many other vendors adopted TLC’s FLEx data in support of this
goal.
In 1994, intense competition arose between DaVinci Systems (then a unit
of
Dynatech) and Corporate Communications Consultants, both manufacturers
of
telecine color correctors and both TLC resellers. To gain exclusivity,
DaVinci
wholly acquired the TLC product line from Time Logic in October 1994. Gary
Adams joined DaVinci at that time. For DaVinci, Jim Lindelien redesigned
the
TLC to synchronize up to six VTRs, and ported the design to Prolog Inc.’s
25 MHz
16-bit Intel 386 STD-bus computers running MS-DOS. This version was called
"TLC2."
DaVinci simultaneously migrated TLC to a single printed circuit card, for
direct
plug-in into their color correctors. TLC continues to be sold as of this
writing, with
more than 900 systems installed since the DaVinci acquisition. An early
project to
port TLC’s Forth code to C was abandoned. For many years, Gary Adams has
maintained and extended TLC’s Forth sources to add support for new transports
and editorial features.
-Jim Lindelien
November 2002
