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Re: DVNR



In a message dated 98-06-25 16:05:32 EDT, Barry Newman wrote:

<< Some of the many thousands of people who are connected with the various
aspects of the motion picture industry rarely go to a  theater or view their
work on home video so don't really know the fate of their work. >>

<< I don't work in the telecine area but that doesn't mean that I don't have
an eye to recognise what DVNR is and what destructive results it is capable
of. >>

Mr. Newman,

In the first part of your posting, you admonish some of us poor types who work
on films and videos but then don't have any idea what the end results of our
work look like because we don't go movies or watch television in our free
time.  There actually are some people like that in this business, but they are
few and far between.  The majority of us know only too well what our stuff
looks like on cable, broadcast, or home video, and we're usually the first to
bemoan the fact that theatrical projection has been reduced to an automated
vending machine business rather than the skilled trade it once was.

You say you have an eye "to recognize what DVNR is and the results it is
capable of."  Really?  What "is" DVNR, and what are its "results?"  I helped
test some of the first prototype Noise Reducers the Digital Vision company
(that's what DVNR stands for) brought over to this country, and have been
taking care of a production unit for a couple of years now.  I can tell you
how much painstaking work went into engineering those units, and I can tell
you that when they are working properly--which is almost always--what you see
are crystal-clear, noise free, and sharp pictures, about as good as film ever
gets on a video screen.  

When we say the DVNR has to be used sparingly and carefully, what we mean is
that it was designed with a lot of power so it can cope with really poor
images.  Just like a car that can be driven over the speed limit and thereby
earn you a ticket, if you push a video noise reducer or image enhancer too
far, it does too much work on the images, causing artifacts.  These have
actually been used in some cases (music videos, for example), but we generally
try not to let that happen since it compromises the original pictures.  

Which brings me to another point.  An actual Digital Vision noise reducer is
an extremely complicated and costly piece of equipment.  Consequently, about
the only place you find them is in color correcting suites, usually under the
control of a colorist who is expected to be knowledgeable in their operation.
These are not things that are routinely found in tape duplicating facilities
or laserdisk pressing plants.  To say that DVNR is being done downstream
(after it leaves "our" control) and this is ruining home video doesn't really
make a whole lot of sense when you stop and think about it.  Why would anybody
pay a colorist to transfer film to video, presumably passing it through a DVNR
or some other brand of noise reducer before it gets to tape, then do all the
other steps in video post production, and then go to the trouble and expense
of putting the material through a DVNR again?  

Video technology has come a long way in a very short time.  In particular,
video compression is now common in all the newer professional and semi-pro
tape formats such as DCT, Digital Betacam, Betacam SX, DV, DVCam, and DVCPro.
Many nonlinear editing systems are also based on compression.  And there's
going to be a lot more coming down the road: both DVD and the American and
European digital TV broadcast standards rely on compression. No video
compression scheme yet developed is 100% perfect; they all are capable of
putting artifacts into the picture under some circumstances.  I think it is
far more likely that many of the problems noted at the start of this thread
are because some of this new compression technology is still in its infancy,
and not due to one particular piece of equipment that is long established and
well regarded in the industry.

Best regards,
Christopher Bacon


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