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Posted by MovieStuff on 04/29/06 03:24
> Derek Gee wrote:
> I have seen problems when using NLE editors to interpolate film speed. For
> example, 16mm film shot at 16-18 fps was transferred at 24fps. Using two
> different brands of NLE editor software to bring the rate back down close to
> original shooting speed left all kinds of weird visible artifacts. Please
> explain how your interpolation works differently from the NLE software.
I think the problem you are describing starts with the film being
transferred at the wrong speed. If, for example, you have 15fps footage
and you transfer it, instead, at 24fps on a Rank, then it already has
pulldown frames built in, which are difficult to remove and will
definately produce some weirrrrrd artifacts if you try to change the
playback speed back to 15fps after transfer using any sort of speed
change software. But, if you ask the Rank operator to simply transfer
at 15fps (or actually 14.97) to begin with, then the Rank will
automatically use a different pulldown pattern that puts each film
frame neatly on two consecutive video frames. Or, you could ask the
Rank operator to transfer at 30fps (29.97) and end up with each film
frame on an independent frame of video, which is really ideal because
then you can apply ANY speed change you want without the types of
pulldown artifacts you are describing.
Likewise, with the WorkPrinter and Sniper units, each frame of film
exists on an independent frame of video with no interlaced motion
artifacts within each frame. In other words, even though a standard
interlaced NTSC or PAL camera is being used to capture each frame,
nothing moves during the first and second field scans because the frame
is held stationary during exposure, so the computer will end up seeing
those two fields together as a single, progressive scan frame. As such,
you can then apply any pulldown pattern necessary to create the speed
desired, just a Rank does.
For instance, if you need 15fps, then CineCap will just double every
video frame. If you need the classic 2-3 pulldown, then it will create
an interpolated frame pattern, just as the Rank uses. If you need
18fps, then it will create yet a different pattern. But what you can
NOT do is apply, say, a 15fps pulldown pattern to footage that has
already been altered to 24fps with a 2-3 pulldown pattern. THAT appears
to be the problem you are describing above, where you have footage that
was shot at 16fps but was inadvertantly transferred at 24fps, then run
through NLE software (which is never the greatest for speed changes,
anyway) to try and bring back down to 16fps. You can do it but you
would need to first use software of some kind to remove the pulldown
frames from the 24fps footage, render that out, then use that new
pulldown-free footage to convert to 15fps (or 16fps, if needed).
So the problem you are describing isn't a problem with the CineCap
software, because the CineCap software is depending on you having total
frame discretion, where the initial captured file has one film frame
per video frame. Even though NLE systems typically do a poor job of
telecine speed changes compared to CineCap, any NLE system will do a
much better job if you remove any pre-existing pulldown frames before
applying a new speed change pattern. Likewise, if you try to use
CineCap software on film that already has a pulldown pattern in it,
then it is going to look very, very funky. :)
> > More specifically, regarding the qualitative difference
> > between our units and a Rank, please see the comparison done in PC
> > magazine where footage was sent to us and to a lab with a Rank Turbo:
> >
> > http://www.moviestuff.tv/whats_new.html#Sniper%20vs%20Rank%20in%20PC%20Magazine
>
> A favorable comparison, but in the still photo above, the Rank transfer has
> better shadow detail and more pleasing flesh tones.
Certainly not $249,000 worth of shadow detail. And if you look at the
last photo, the Sniper still is clearly better, with the Rank transfer
washed out with lousy color. But in truth, the results are so close
that operator input probably accounts for more of a difference than the
technology used.
>
> The big problem with the Moviestuff products is the inability to transfer
> sound films.
Agreed. We have not concentrated on sound units because the demand has
mainly been for silent film footage. However, we have been pestered so
much by archive houses that we are actually about to release some new
sound units that will allow frame accurate transfers with perfect,
frame accurate lip-synch. We're pretty excited about it. They should be
very popular.
Roger
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