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Re: Digi beta

Hi Graham,

I know exactly what you mean. This colour shift problem between
stop and run exists since Digital Betacam was born. It causes trouble
especially during colour grading with a Digi-Beta as main or reference
source of a digital colour processor.

The fact is that "stop" on a Digi-Beta-VTR is not a legal working 
condition, even if switched to "PB" and a picture can be seen on the 
SDI video output in "stop". To see the true picture, "jog" should be 
active without turning the wheel (or step one frame for- or backwards 
with the remote-/edit-/telecine-controller). Please note that the still
timer will set the VTR back to "stop" again, also current controller
do so after "preroll", "cue" or things like these.

As this is all a little boring, I've worked out a soluton for this 
problem some time ago:
Use the Digi-Beta-Framestore to override the discussion above. Set 
position 906 of the extended user menu to enable, this function is 
named "stop freeze control". If you do so, the VTR keeps the last 
field or frame frozen when hitting "stop", the picture looks exactly 
the same as in "play" or "jog", no colour shift any more. Please note
that you can do also full frame resolution in stop (if position 121
"DT mode" is set to "frame") and the picture remains also after
the VTR has unthreaded the tape (standby off, but tape in). Here you
can save running hours of your head drum, because there is no need
any more to keep it running to get a still image (decrease your still 
time, if you want).

I hope this helps to "bypass" your green/magenta colour shift, it has 
nothing to do with MSB/LSB or SDI video path, that's all o.k.!

Stefan Sedlmeier
Engineering Manager
ARRI TV-Produktionsservice GmbH  Tuerkenstr. 95  D-80799 Muenchen
Phone +49 89 3809-1876  Fax +49 89 3809-1549  Email ssedlmeier at arri.de

  HDTV discussion thread is at http://www.alegria.com/telecine/hdtv.txt
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