[tig] RE: I'm worried and angry

mhafner at imdb.com mhafner
Mon Oct 20 10:15:01 BST 2003


Hello,

#I don't know what a "PO" house is.

It was a typo. I meant mastering facility/post production house.
It was DVD/HD mastering related though, not DI.

#But unless it was a high end facility, dealing with
#high end long form product (which you're likely to find only in Los Angeles
#or New York), it wouldn't provide you with the perspective I think you need.

One of the resasons I'm here is to get (more of) that perspective.

#If you had come in here asking questions, and
#proposing that you saw something during a screening that seemed to be an
#indication of a problem, technical or otherwise, you would likely have
#gotten a very different reception.

If you look at my first posting about this you will see that I did not
accuse anyone of being responsible beyond having participated in the
creation of the look of the print. I merely stated facts and gave a 
diagnosis of the technical cause of the problem I saw, based on my
experience with DNR. Then I asked for explanations how something like
that can happen. I'm not a politician and I could have been 'nicer',
but as you know by now, the whole experience had a strong emotional
impact on me. 

#I might see a scene in a
#movie that appears inordinately grainy, but if I talk to the
#cinematographer, I'm not going to start out by saying "that sceen looked
#like crap." I'm probably going to say "Did you intend for this scene to look
#grainy, or were there some problems that you had to deal with?". Sometimes,
#presentation is everything.

Sure. Only in the case of "Seabiscuit" I would have to ask: Did you intend
for this film to look grainy or were there some problems that you had to deal
with in 95% of the film? (Sounds silly, doesn't it? But the film is grain
reduced throughout).

#And the answer to your question about aperture correction is that when
#transferring to NTSC or PAL, the image is essentially being "downconverted"
#because the telecine is seeing much more resolution than the video system is
#capable of.

There is EE on most HD transfers too.

#When it's downconverted, it is usually a bit "soft" when
#displayed on an NTSC or PAL monitor.

That's up to the sharpness of the HD transfer and the quality of the
downconversion filter, where you need to find a good balance between
aliasing and loss of sharpness. As in digital audio, best results require
quite some oversampling followed by downconversion (in the telecine for
direct HD and SD, and for SD from HD where HD is already oversampled
relative to SD).

#Thus the use of some mild aperture
#correction to put some sharpness back.

As long as it's mild it's ok. But when people walk around with haloes
it's no longer mild. Not to mention that the high frequency boosting
causes problems with MPEG encoders just like DNR. It's a very typical
scenario for a technical chain where the elements are not working
optimally together, one trying to fix what the other did not do right
and making things often even worse in the process.

#It is a matter of opinion as to how much aperture correction is
#necessary on any given image, but if it were "turned off" you would be
#seeing an image that is simply too soft, especially when displayed on
#consumer monitors.

Yes, the real reason for appearance of (sometimes hideous) EE on DVD is that
the picture is 'optimized' for small screens watched from a safe distance
by people that can not be trusted to use the built in sharpness control of
the set if things don't look crisp enough from their position. Forget about
the other people with high quality sets or people with projectors that
will see a big image, sitting only ~1.5-3 screen heights away.
Again there is a fitting audio analogy. Do you frequency boost your CDs
so they sound 'best' in the car and on the ghettoblaster or on your mid to
high end hifi? When CD came out it was often the former, now, thank God,
it's usually the latter.

> I agree that the final decision is surely the client's since he pays.
#You are still missing the point.
#Money has nothing to do with it.  IT'S THE CLIENT'S PROJECT, NOT YOURS

Agreed, but see the doctor example. It's the patient's leg as well.
How do you stop your client from hurting himself in an area where he's
not the expert but you are? And most DOPs and directors are not experts 
in digital image processing and its tools. They are learning now to deal
with these developments.
cheers
						Michel Hafner






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