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Cantar-X User Manual v2.44 (r14) 2013 March 21
p.46
p.46
On location
To later reunite images and sounds,
a common TC must
be stamped
on both:
1
Select an
AutoSlate
channel in AUDIO/TC.13, the clap-
stick sound is detected and the matching TC is inserted into
the sound report; this TC, keyed by the editor on the image
of the clapstick, will then be used as if the camera was
timecoded. This is the simplest and most accurate method
ever invented. You can also use a Smart-Slate (the recorder
sends its TC to a display filmed at the head or tail of each
take), but this is not as accurate as the AutoSlate.
2
Send the camera's 'Video-TC' to the recorder set in
'Ext. Clock' mode and 'record-slaved' by LTC breaks (p.21).
This method can't work on multi-camera shoots, and relies
upon a cable or radio transmitter.
3
Install an Audio-TC generator (Ambient or Denecke) with
tri-level sync to replace the camera's internal Video-TC with
an external Free-Run Audio-TC identical to the recorder's TC.
This method is not applicable to all video cameras; it doesn't
let the camera generate a continuous Video-TC, something
necessary to some editing systems. It will work perfectly the
day all video-cameras and NLEs are designed for it.
4
Record the TC of the audio recorder on one audio track
of the camera(s), preferably "A3" (on a two-track consumer
camera, record audio on A1 and TC on A2, listen to the
A1 audio with a mono-jack). The TC can be sent by cable
(clumsy but cheap), by radio (beware the interferences) or
locally delivered by a generator such as a GMT (p.56)
attached to each camera (use a line input; turn 'OFF' the
automatic-gain if you use a mic-input).
Method-4 works on
all kinds of cameras, gives total freedom of movement for
multi-camera shooting, and leaves the continuous Record-
Run Video-TC (different in each camera) untouched. This is
of great value when it comes to batch digitize videotapes
under the 'Optimize for Speed' mode.
In the edit suite
This tutorial is dealing with on-location 'Method-4' only.
When using a multi-track recorder, the common practice is
to deliver six ISO tracks and a mixdown on two extra tracks.
This mixdown is also sent through Line-out or Digi-out to the
camera's A1 A2 audio tracks to let the Director immediately
verify the last take and to later look at the day's rushes.
Because of a MediaComposer limitation which forces the
editor to make a preliminary choice between using or not
the camera recorded mixdown,
the successive states of the post-chain must constantly deal
with this duality.
A- Import audio
• editing with the Cantar ISO tracks
Demanding editors work with all of the ISO tracks (including
the mixdown) to insert wild tracks or emphasize the pres-
ence of an audio event left unheard within the mixdown.
In this case the video material should be imported under
the
V A3
mode, not V A1 A2 A3 which would import the
camera recorded mixdown, thus preventing later import and
Autosync of the ISO tracks.
Once editing is done, the Audio-EDL 'TC sorting' will be
done with
Filetags
, the assistant editor must put them in the
Avid 'soundroll' column prior to the import.
• editing with the camera recorded mixdown
If the editor prefers to work with the camera recorded mix-
down, the import must be done under
V A1 A2 A3
: the
audio is coming from A1 A2 and the Audio-TC from A3.
Once editing is done, the Audio-EDL 'TC sorting' will be
done with '
TapeIDs
', the assistant editor must put them in the
Avid 'soundroll' column prior to the import.
B- Extract TC
During the import digitization, Avid MediaComposer/
XPressPro and Apple FCP w/ AUX-TC-FCP can extract the
Audio-TC from A3 (or from A2 on a two-track only consumer
camera). The Audio-TC, correlated to the Video-TC, doesn't
occupy an audio track of the NLE system. It will be used to
'Autosync' imported ISO tracks and to construct the Audio-
EDL (Edit Decision List). Read the 'PostChain':
http://www.aaton.com/documentation/
C- Differentiate TCs
• editing with the Cantar
ISO
tracks
No problem here: each audio file carries its own
filetag
in
which it is impossible to find two identical TC(h).
• editing with the camera mixdown
There are no 'filetags' in the camera recorded mixdown,
the only link with the Cantar ISO tracks is the Audio-TC.
But because the CMX Audio-EDLs generated by NLE
systems don't carry the Audio-TC(d) date, the Audio-TC(h)
every day shows the same working hours: it can't offer a
solid 'auto-conform' path from the edited mixdown to the
original Cantar ISO tracks; the only way is the 'TapeRef
solution'.
TUTORIAL
CAMERA SYNC [1]
