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Re: "Dirt Boxes" DVNR




Craig Nichols asked;
    >> concerning dirt and scratch removal with the Digital Vision DVNR or the
BTS
    >> MNR-11.  Now that more people have perhaps seen, and or used both
systems,
    >>what is the general opinion about the merits or shortcomings of either
box?

We use fully configured DVNR 4x4's and we, like everyone else, did extensive
comparisons
between these and the MNR11 before making our choice. At the time we thought
that the
DVNR had the edge on the MNR in terms of dealing with black & white transients
with its
ASC option whilst the temporal / recursive filtering was about equal. The
stability option
on the DVNR and the true 4x4 processing were the real deciding factors although
now
nearly all our critical stabilization is performed at a compositing station!

Because most of the material we work with is new we have never really pushed the

ASC but when playing with our test damaged film and tape its effectiveness is
always
a compromise between improvement and the further deterioration of the image via
the
introduction of motion disturbance. It is at this point that the integration of
any box with 
the telecine suite controller becomes important as it is always necessary to pre
- programme
intensive improvements into the Pogle independently of colour correction etc. 

To open the discussion further this compromise between filtering and motion
detection
is equally as relevant for recursive / temporal filtering so it has been very
interesting for 
us this past week as we have loaded one of the DVNRs with the new ANR option and

have been putting the old and new head to head.  The difference is astounding.
The new
boards allow you to push the filtering to a level that hits say blue light
exposure / grain
noise and remove it whilst not producing motion lag or any image retention.
Recording 
the output of the same material passing through both boxes at the same time
proved that
the original boards were producing artifacts at luminance / chroma levels of
around 4 /5
whilst the ANR was artifact free at levels of 10 / 11 and could be pushed to the
eye right 
up to the 13>14 mark. More importantly for good quality sources where neither
unit was
being pushed the new boards were felt to be subjectively cleaner and more
effective by all
of the people here.

The ANR also lets you boost or fade the luminance reduction in colour selectable
picture
areas. You can only choose one colour at a time and there are 12 options ie 3
Primary and
3 Secondary TV colours with 30 degree shift combinations. Whilst this seems a
bit restrictive
as we are all used to isolating colour on the basis of hue, saturation and
luminance values,
at least it may help with adding colour to overex'ed blue skys, and it will also
be interesting
to see how it helps blue screen work by either boosting or maybe fading the
reduction to 
give harder edges. The ANR can also be more closely optimized to your film type
by setting 
where, in terms of black & white, the increased reduction takes place although
this is a four
level preset and on the average picture it was quite hard to subjectively asses
the differences.

All of the above adds another level of complexity to the operation of the DVNR
and makes it 
even more important that your controller can display the data in a logical way.
On the Pogle
the new options are selected in the DVNR set up window and once turned on the
new buttons
appear in the normal control window and are activated by point & click. 

There is apparently a new static scratch concealment filter due soon ( NAB??)
which we will
also look at but the line between the cost of these updates and the selling of
them to our
clients is being fast approached. Whilst the ANR is justified in that it will be
of benefit to all 
the work passing through our rooms it will push the cost of each fully optioned
DV box up
considerably and these costs, at least in London, can't always be added into the
rate card.
The occasional bad camera / processing scratch that we get can be removed
perhaps
more cost effectively in Flame /Henry /Advance than for us to invest in more
real time 
"dirt " removal tools. Having said that if the same improvements were made to
the ASC option
as have been made to the recursive filter then the box ought to be totally
suitable for all
real time cleanup operations.

Seamus O'Kane. 
VTR Ltd London.