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From two to three (VITC lines)
Alan Lambshead/Evertz Telecine Support wrote to the TIG:
> Every time I hear about 3-Line VITC it is referred to as an AATON
> For the record Randy and all:
> The 3 - line VITC standard was co-developed by Evertz, AATON, AVID
> and Lightworks and is based on the original Evertz 4025 2-line
> VITC format (which has one line for timecodes, and one line for
Further to your remarks, I hasten to confirm that 3Line VITC is not an
AATON standard; it is based on a merging of two different systems, one of
which is indeed 4025 2-Line VITC (see addendum below).
Given that Aaton offered 3LineVITC in all its KEYLINKs back in OCT 93,
that Lightworks was exploiting Keylink 3LineVITC inserted tapes
as of SEPT 94, and that the Evertz-designed Avid Media Reader
started handling 3LineVITC in NOV 96 only...
3LineVITC -- by default -- appeared to be an 'AATON' feature
for a full three years.
During these years Aaton was left alone to promote 3lineVITC, while
Evertz continued with its 2LineVitc. It is thus quite natural that video
engineers, colorists and editors tend now to associate 3LineVITC to
our name; this is no doubt why Randy correctly wrote:
> Aaton introduced and Evertz now supports the 3 line system,
> which allows room for other information to be encoded as well.
We are happy to see 3Line VITC is no longer a standard exploited by
a couple of European manufacturers, but is now a Recommended Practice
for film to video data transfer.
Features of 3Line VITC:
- The first VITC line (Video TC + Video reel#) remains compatible with
standard VITC readers
- The second VITC line (Keycode) is to be used by negative cutters
as a safety belt in case something went wrong in EDL handling.
- The third VITC line (Audio TC) is used for on-the-fly audio sync
with precision LTC can't offer.
- Common practice: NTSC line# 16-17-18; PAL line# 19-20-21.
The 3LineVitc system has been so successful that many customers have
asked AATON to provide a *fourth line* option which will allow
recording of: start of takes, RGB transfer points, scene & take,
facility ID, title, etc. We call that Keylink option 3LineVitc[+].
Nothing stands still in the film/video industry, nor does it at Aaton.
LARGE ADDENDUM to give Caesar what belongs to Caesar...
(and for the record, if you prefer).
The twice-the-same 2LineVitc was, and to date remains, an Evertz
system (two for video TC, two for Keycode).
Since 1984, Aaton has been, and remains, the defender of in-camera
AudioTC (AatonCode). Considering the playback quality of VTRs and
the sophistication of current VITC readers, Aaton proposed, as of JAN 93:
1- not to repeat the same information twice to leave the
vertical interval free for more data recording,
2- to insert a line devoted to AudioTC between the two 'normal'
lines (say 17, between 16-18). Hence the original name: 3rd Line VITC.
In MAY 93, during the Montreux Symposium, Avid engineers organized
a meeting with Aaton and Evertz to settle on a single VITC system.
In SEPT 93 Aaton/Evertz came to an agreement merging their two systems
under the 3Line Vitc name.
In OCT 93 Aaton retrofitted all its Keylinks (software v5.12)
and its Sorter (VITC reader/post burner) to make them 3LineVITC
In MAY 94, modifications were requested by Lightworks and Evertz.
In JUNE 94 Aaton sent a 3Line VITC draft to the SMPTE adhoc
committee; it was agreed that the Ontario based Evertz
-- closer to SMPTE venues -- would be the 3LineVITC defender.
In NOV 94, Lightworks offered a 3LineVitc capable software
(Lightworks hardware already read normal VITC), and the system was
'put into practice' mainly in England where the concentration of Keylinks
(85% facilities equipped) and Lightworks was the highest.
In the meantime Avid had asked both Aaton and Evertz to develop a
3lineVITC reader; Evertz won the bid and developed the Avid Media Reader
which -- for reasons I don't know -- read only the Evertz
'twice-the-same-two-lines' for a good while.
In NOV 96, the Evertz designed AMR finally read 3LineVITC.
In JAN 97, Alan Lambshead wrote:
> Every time I hear about 3-Line VITC
> it is referred to as an AATON standard.
A note in closing: 3Line VITC has many other applications outside
the telecine world. For example, both Panavision and Aaton use it
to insert film camera related data (such as start-stop, speed,
AatonCode etc.) into the video signal of their video-assists.
The 3rd line makes it easy to post-sync the sound of the main audio
recorder to the video-assist images.
Jean-Pierre Beauviala jpb at aaton.com www.aaton.com